THE  LIBRARY 

OF 

THE  UNIVERSITY 

OF  CALIFORNIA 

LOS  ANGELES 


THE    SCIENCE   AND    PRACTICE    OF 
DENTAL   SURGERY 


PUBLISHED    BY   THE  JOINT   COMMITTEE   OF 

HENRY  FROWDE  and   HODDER   &   STOUGHTON 

AT    THE     OXFORD     PRESS     WAREHOUSE,     FALCON     SQUARE 

LONDON,    E.C. 


THE 

SCIENCE  AND  PRACTICE 


OF 


DENTAL  SURGERY 


F.DITFl)  BY 

NORMAN     G.    BENNETT 

M.A.,  M.B.,  B.C.  (Cantab.),  L.D.S.  (Eng.) 

,.>,,  ynv   T,.  sr    (KORCE'S   HOSPH  \1.  AND    IHH   KnV.M,   DENTAL   HOSPITAL.  LONDON  ;    MEMBER  OK  THE 
"""•  "i'^rr^AM^^^N    DENIAL  SVR.ERV.    ROVAL  COLLECT  OE  S.R.EO.S   OE   EN.LANO 


WITH  AN  APPENDIX  ON 

DENT./^L   JURISPRUDENCE 

P.  B.    HENDERSON,   B.A.  (Oxon.) 

>i„lidtor  of  Ibr  Siipifrnt  Court 


iriTH   MNE   HiWDKED   AND    MSETY-THREE   lEllSTRATinSS 


NEW  YORK 

WILLIAM     WOOD     AND    COMPANY 

M  D  C  C  C  1"  X  1  \' 


g^wMMj 


wu 


PKEFACE  ^ 

In  sul)mitting  this  work  to  my  colleagues  in  the  Dental  Profession,  I  feel  that  a  few  intro- 
ductory remarks  may  not  be  out  of  place.  Dental  Surgery  has  advanced  so  rapidly  within  recent 
years,  both  in  the  many  branches  of  science  on  which  it  is  based  and  in  the  intricacies  of  manipu- 
lative procedure,  that  the  production  of  a  new  comprehensive  work  by  a  single  WTiter  has  become 
almost  an  impossibility.  Certain  defects  are  usually  associated  with,  if  not  necessarily  inherent 
in,  a  work  by  many  writers,  and  one  object  that  I  have  had  in  mind,  from  the  commencement  of 
the  long  period  during  which  the  work  has  been  as  continuously  in  hand  as  the  demands  of  other 
duties  permitted,  has  been  to  eliminate  these  defects  as  far  as  jiossible.  I  have  endeavoured  to 
impart  unity  of  conception  and  style  to  the  whole,  and  to  prevent  overlappino-  except  where  it 
seemed  permissible  that  a  particular  subject  .should  be  presented  from  different  points  of  view- 
Cross-references  have  been  liberally  inserted.  Another  object  that  I  have  had  in  view  has  been 
to  combine  the  scientific  with  the  practical,  for  neither  is  of  much  value  to  the  practitioner 
without  the  other,  and  in  a  work  of  this  kind  it  is  desirable  that  their  nnitual  interdependence 
should  be  brought  prominently  before  the  reader.  The  work  does  not  represent  any  particular 
school  of  thought  ;  the  contributors  belong  not  only  to  the  United  Kingdom  but  to  the  most 
distant  parts  of  the  Dominions  beyond  the  Seas,  and  an  effort  has  been  made  to  include  everytliinw 
in  pathology  or  practice,  from  whatever  country  or  source,  that  might  be  of  value  to  the  modern 
practitioner.  Obsolete  theories  in  pathology  or  abandoned  metliods  of  treatment  have  been 
omitted,  or  only  briefly  referred  to  where  their  historical  interest  is  great. 

In  all  these  objects  I  have  been  well  supported  by  my  contriljutors,  and  I  wish  to  take  this 
opportunity  of  thanking  them  most  sincerely  for  the  careful  way  in  which  they  have  considered  the 
principles  laid  down,  and  written  their  chapters  in  conformity  with  the  scheme  that  I  outlined- 
and  also  for  allowing  me  so  much  freedom  in  making  such  alterations  as  I  thought  necessary  in 
the  interest  of  uniformity. 

I  venture  to  think  that  they  have  produced  excellent  woik,  and  managed  to  combine  "eneral 
knowledge  derived  from  the  work  of  others  with  the  subtle  touch  of  individual  experience  without 
which  discussion  on  problems  of  aetiology  and  descriptions  of  manipulative  procedure  have  little 
value.  The  Appendix  on  Dental  Jurisprudence  will  perhaps  afford  my  colleagues  useful  information 
on  matters  of  importance  in  their  relations  with  the  State,  the  public,  and  their  fellows. 

It  is  hoped  that  the  bracketed  numbers  in  the  text  referring  to  the  Biljliographies  at  the  ends 
of  the  chapters  will  be  useful  to  those  desiring  fuller  information  on  any  particular  aspects  of  a 
subject  than  is  po.ssible  in  the  available  space  of  a  text-book.  The  illustrations  must  be  allowed 
to  speak  for  themselves,  but  I  may  say  that  they  have  been  inserted  solely  with  a  view  to  the  elucida- 
tion of  the  text,  or  as  a  better  alternative  to  more  lengthy  descriptive  writing,  and  not  for  mere 
decorative  effect. 

The  chapters  on  Abnormalities  of  Position  have  been  written  by  Mr.  Harold  Chapman  and 
myself,  and  although  we  are  each  responsible  for  our  own  f)arts — he  for  tlie  practical  details  of 
treatment,  and  I  for  the  jiroljlems  of  aetiology  and  classification  and  the  broad  principles  of 
treatment — nevertheless  the  two  parts  have  been  wTitten  in  close  collaboration,  even  to  the  extent 
of  transferring  portions  of  text  already  wTitten  from  one  part  to  the  other  when  it  seemed  desirable. 
In  the  part  dealing  with  the  Mechanics  of  Tooth  Movement  I  have  approached  the  subject 
from  the  purely  scientific  side,  instead  of  dealing  with  it  merely  from  an  empirical  standpoint. 
The  movements  of  teeth  due  to  the  application  of  forces  are  subject  to  the  same  creneral  laws  as 
govern  the  movements  of  other  bodies,  and  a  consideration  of  mechanical  problems  is  necessary 
for  a  proper  understanding  of  them.  My  own  knowledge  of  mathematics  would  have  been  insufticient 
to  ensure  lucidity  or  correctness,  but  I  have  had  the  great  advantage  of  the  assistance  of  mv  brother 
Mr.  G.  T.  Bennett,  M.A.,  F.R.S.,  Fellow  and  Mathematical  Lecturer  of  Emmanuel  College' 
Cambridge.  We  have  endeavoured  to  write  this  part  in  such  a  way  as  not  to  assume  more  than 
an  elementary  knowledge  of  mechanics  on  the  part  of  the  reader,  and  we  hope  that  it  will  be  found 
intelligible.    It  is  perhaps  unfortunate  that  the  subject  is  necessarily  a  mathematical  one,  if  treated 


vi  PREFACE 

iu  a  scientific  manner;  and  although  this  point  of  view  may  seem  somewhat  remote  from  the 
practical  details  of  application,  I  wish  to  emphasize  the  fact  that  the  successful  adoption  of 
the  latter  is  more  dependent  on  theoretical  knowledge  than  is  generally  believed  to  be  the  case. 
I  may  at  least  state  with  confidence  that  the  truth  of  the  laws  enunciated  is  indisputable. 

The  matter  of  terminology  has  been  a  source  of  some  difficulty.  Many  dental  \\  ords  in  common 
use  are  incorrect  etymologically  or  in  their  strict  meaning,  and  it  is  much  to  be  desired  that  an 
authoritative  Committee  on  Dental  Nomenclature  should  consider  the  whole  subject.  Until  this 
has  been  done  it  seems  unmse  to  make  many  changes.  However,  such  accepted  alterations  in 
anatomical  nomenclature  as  occur  in  comiection  with  dental  science  have  been  adopted,  and  certain 
terms  employed  in  the  chapters  on  Orthodontics  need  explanation.  Among  the  former  the  more 
important  are  the  following  : — 

Ectoderm         .        .        .   instead  of  Epiblast. 

Mesoderm         .        .        .  ,,  Mesoblast. 

Entoderm         .        .        .  ,,  Hypoblast 

Spinal  Medulla        .        .  ,,  Spinal  Cord. 

Stomatodaeum        .        .  ,,  Stomodaeum 

Mandible  .        .        .        .  ,,  Inferior  Maxilla 

Mandibular  Fossa   .        .  ,,  Glenoid  Fossa 

Lymph  Vessel  .       .        .  ,,  Lymphatic 

Lymph  Gland  .        .        .  ,,  Lymphatic  Gland 

Inferior  Alveolar  Canal  .  ,,  Inferior  Dental  Canal 

Inferior  Alveolar  Nerve  .  ,,  Inferior  Dental  Nerve 

Mandibular  Foramen     .  ,,  Mental  Foramen 

Inter -articular  Meniscus  ,,  Inter-articular  Cartilage 

Maxillary  Sinus       .        .  ,,  Antrum 

Mandibular  Articulation  ,,  Temporo-mandibular  Articulation 

Medial       ....  ,,  Mesial 

Auditory  Tube        .        .  ,,  Eustachian  Tube 

Some  of  these  are  in  current  use.  The  one  that  occurs  most  frequently  is  ''  medial  "  for 
"  mesial  ".  "  Mesial  "  and  "  proximal  "  are  used  in  different  senses  in  contradistinction  from 
"  distal  ".  '■  Proximal  "  and  "  distal  "  are  words  of  Latin  origin,  whereas  "  mesial  "  is  Greek, 
and  it  is  obvious  that  the  Latin  form  "  medial  "  is  the  more  correct.  We  still  have  the  other  Latin 
form  "  median  ",  meaning  at  the  centre,  as  distinguished  from  "  medial  ",  toimrds  the  centre.  To 
indicate  the  surfaces  of  teeth  normally  in  contact,  the  word  "  approximal  "  has  been  generally 
used  and  the  words  "  interstitial  "  and  "  proximal  "  avoided.  The  objections  to  the  former  are 
oljvious,  and  the  use  of  the  latter  invites  confusion  with  the  meaning  of  the  word  when  used  in 
contradistinction  from  ''  distal  ". 

It  has  seemed  necessary  to  modify  some  of  the  terms  used  in  Orthodontics  or  the  meanings  of 
them,  and  in  some  cases  to  coin  new  ones.  "  Protrusion  "  and  "  retrusion  "  are  used  with  their 
usual  significance  to  indicate  a  forward  or  backward  position  of  the  teeth,  especially  the  anterior 
teeth.  But  it  is  now  well  understood  that  such  forward  or  backward  position  may  involve  the  whole 
tooth,  or  only  the  crown ;  in  other  words  tlie  tootli  may  be  completely  out  of  place  or  only  tilted. 
For  the  latter  I  have  used  the  terms  "  proclinatio7i  "  and  "  retrochnation  ",  suggested  by  Dr.  Sim 
Wallace,  on  the  analogy  of  inclination,  and  for  the  former  I  have  ventured  to  coin  the  terms  "  pre- 
placement  "  and  "  postplacement  "  on  the  analogy  of  "  displacement  ".  For  forward  and  backward 
positions  of  the  jaws  themselves  the  anthropological  terms  "  prognathism  "  and  "  retrognathism  " 
are  used.  It  may  be  undesirable  to  use  these  with  a  pathological  or  semi-pathological  significance, 
but  it  is  convenient  in  distinguishing  between  malpo.sition  of  the  teeth  alone  and  abnormalities 
involving  the  bones  themselves.  "Imbrication"  is  used  to  indicate  overlapping,  especially  of 
the  lower  incisors,  due  to  insufficient  space.  My  use  of  the  term  "  occlusion  "  and  its  congeners 
I  have  endeavoured  to  explain  and  justify  in  the  text  itself.  The  words  '"  open  bite  "  and  "  close 
bite  "  have  been  deliberately  retained.  Tliey  may  be  colloquial,  but  they  are  not  on  that  account 
the  less  scientific  or  clear  in  their  meaning,  and  I  do  not  consider  that  any  of  the  terms  that  have 
been  proposed  as  substitutes  have  any  advantage  over  them  on  either  of  those  grounds. 

"  Pre-normal  occlusion  "  and  "  post-normal  occlusion  "  are  used  with  their  generally  accepted 
meaning,  which  is  perfectly  clear.  I  regret,  however,  that  they  have  the  defect  of  being  not  merely 
descriptive  terms  but  of  connoting  a  diagnostic  conclusion.  It  is  always  necessary  in  using  them  to 
say  which  jaw  is  referred  to.  For  example,  the  condition  in  which  the  medial  two-thirds  of  the 
first  lower  molar  occludes  with  the  upper,  instead  of  the  distal  two-thirds  of  the  lower  occluding  with 


PREFACE  vii 

the  upper,  as  normally,  is  perfectly  well  kno\\7i.  This  condition  obviously  may  be  due  to  mal- 
position of  either  tooth,  i.e.  it  may  be  post-normal  lower  or  pre-normal  upper.  It  is  much  to  be 
desired  that  a  term  should  be  invented  to  indicate  simply  the  relationship,  without  further  diagnostic 
conclusion. 

The  word  "bow"  has  been  used  throughout  instead  of  wire  "arch".  The  latter  term  is 
obviously  likely  to  lead  to  confusion  with  "  dental  arch  ",  and  moreover  is  incorrect,  because  the 
appliance  is  not  used  to  support  anji:hing.  The  term  "  bow  "  simply  indicates  a  curved  piece  of  wire 
adapted  to  the  "  dental  arch  ".  "  Ligature  "has  been  used  generally  for  all  forms  of  attachment — 
whether  wire,  silk,  or  otherwise — of  the  teeth  to  the  bow. 

In  a  work  of  this  kind  many  minds  are  employed,  and  I  have  pleasure  in  expressing  my  indebted- 
ness to  many  kind  helpers  besides  my  contributors.  Mr.  F.  G.  H.  Armin  rendered  valuable  assist- 
ance in  the  early  stages  by  bibUographical  researches,  which  assisted  the  contributors  in  their  wTiting 
and  formed  the  basis  of  the  Bibliographies  at  the  ends  of  the  chapters.  Mr.  E.  L.  Fickhng  is  respon- 
sible for  the  Contents  pages  and  Index,  and  has  given  me  great  help  by  his  careful  reading  of  the 
proof-sheets.  Mr.  J.  F.  Gow  has  kindly  performed  a  similar  oflSce  with  many  of  the  final  proofs. 
The  illustrations  in  the  chapter  on  Abnormalities  of  Size,  Form,  and  Structure  are  from  drawings 
by  Mr.  W.  H.  Dye,  formerly  House  Surgeon  at  the  Royal  Dental  Hospital.  I  am  obliged  to 
Dr.  Harold  Austen  for  looking  over  the  various  prescriptions  occurring  tliroughout  the  book 
to  ensure  correctness  and  uniformity  of  style. 

Li  connection  with  my  chapters  on  Orthodontics  I  have  pleasure  in  recording  the  assistance  given 
me  by  friends  whose  names  appear  under  the  figures  of  models,  etc.,  that  they  have  kindly  lent, 
particularly  Mr.  J.  H.  Badcock,  Mr.  Harold  Chapman,  Mi-.  George  Northcroft,  and  Mr.  J.  E.  Spiller. 
The  figures  under  which  my  name  appears  are  from  photographs  taken  by  Mr.  George  Payne  of 
patients  under  my  care,  or  of  material  prepared  by  myself,  and  I  am  indebted  to  successive 
House  Surgeons  in  the  Children's  Department  of  the  Royal  Dental  Hospital  for  their  help  in 
this  matter,  namely,  Mr.  G.  T.  Yonge,  Mr.  H.  D.  Stephens,  Mr.  T.  C.  Kidner.Mr.  A.  Lawrey,  and 
Mr.  A.  L.  Packham. 

I  wish  to  express  my  thanks  to  the  Royal  Society  of  Medicine,  Sir  W.  Ai-buthnot  Lane, 
Dr.  E.  H.  Angle,  Dr.  C.  S.  Case ;  the  Editorial  Committee  and  Editors  of  the  British  Dental  Jourrial  ; 
Mr.  Ai'thur  Underwood,  the  Editor,  and  Messrs.  Segg  &  Co.,  the  publishers,  of  the  British  Journal 
of  Dental  Science;  Dr.  G.  V.  Black  and  the  Medico-Dental  Pubhshing  Co.,  Chicago,  the  pubhshers 
of  his  work  on  Operative  Dentistry :  Messrs.  Appleton  &  Co. ,  of  New  York,  the  publishers  of  Kingsley 's 
Oral  Deformities  ;•  and  to  Messrs.  Rauhe,  for  permission  to  reproduce  illustrations. 

To  Mr.  W.  Rushton,  the  Editor  of  the  Dental  Record,  and  to  the  Dental  Manufacturing  Company, 
I  am  obliged  for  the  free  use  of  blocks  from  that  journal  and  from  the  Company's  catalogue.  To 
Messrs.  Claudius  Ash,  Sons  &  Co.,  I  am  likewise  indebted  for  blocks  from  Aslts  Quarterly  (now 
AsVs  Monthly)  and  from  their  Catalogue.  To  Messrs.  John  Wright  &  Sons,  Ltd.,  of  Bri.stol,  I  am 
indebted  for  the  loan  of  a  block  from  an  article  of  my  own  in  Pye's  Surgical  Handicraft ;  to  Messrs. 
Plucknett,  Mayer  &  Meltzer,  and  W.  Watson  &  Sons,  for  the  use  of  blocks  or  electros  from  their 
catalogues  ;    and  to  Mr.  Frederick  Rose  for  an  electro. 

I  wish  to  express  my  thanks  to  Dr.  E.  C.  Kirk  for  his  cordial  co-operation  in  obtaining  for  me 
electros  from  the  Dental  Cosmos,  and  the  Text-hook  of  Operative  Dentistry,  and  in  getting  permission 
for  me  to  use  them  from  the  various  writers  whose  names  appear  under  these  figures ;  to  the  S.  S. 
\\'hite  Dental  Manufacturing  Company  for  the  supply  of  these  electros  and  others  from  their  Cata- 
logue ;  and  to  Mr.  Henry  Kimpton,  the  English  publisher  of  the  Text-hook  of  Operative  Dentistry, 
for  permission  to  reproduce.  My  thanks  are  due  to  Dr.  Ottolengui,  the  Editor  of  Items  of  Interest, 
and  to  the  Consolidated  Dental  Manufacturing  Company,  the  publishers,  for  the  supply  of  electros 
from  this  journal,  and  to  the  wTiters  whose  names  appear  beneath  the  figures  for  permission  to 
use  them  ;  and  also  to  Messrs.  Adlard  &  Co.,  Bale,  Sons  &  Danielsson,  J.  &  A.  Churchill  &  Co., 
and  H.  K.  Lewis,  for  the  supply  of  electros. 

I  am  greatly  obliged  to  Prof.  Arthur  Keith,  Curator  of  the  Museum  of  the  Royal  College  of 
Surgeons  of  England,  for  allowing  me  to  reproduce  illustrations  from  his  works,  and  especially 
for  permission  to  photograph  specimens  in  the  Museum. 

Mr.  Garrett  and  Mr.  Cray,  the  librarians  of  Messrs.  Ash's  Library,  and  Mr.  Yarrow  of  the  Dental 
Manufacturing  Company  have  given  me  every  possible  assistance  in  the  verification  of  references 
and  other  matters. 

The  artists  employed  on  the  work,  Mr.  Sydney  A.  Sewell  and  Miss  Ethel  Wright,  have  been 
successful  in  carrying  out  the  wishes  of  myself  and  my  contributors,  and  Mr.  Frank  Butterworth 
has  rendered  valuable  assistance  in  photograpliing  specimens  and  preparing  photographs  for 
reproduction. 


viii  PREFACE 

To  tlie  publishers,  Messrs.  Fro%\de  and  Hodder  &  Stoughton,  and  to  their  Medical  Editor, 
Mr.  J.  Keogli  Murphy,  I  am  greatly  indebted  for  much  sympathetic  treatment,  and  especially  for 
the  consideration  they  gave  to  my  opinions  on  various  questions  as  the  work  progressed. 

Certain  details  of  orthography,  syntax,  and  punctuation  to  be  found  in  this  book  are  perhaps 
somewliat  unusual  :  my  authorities  are  cliiefly  The  Concise  Oxford  Dictionary ,  The  Kind's  English, 
and  Rules  for  Compositors  and  Readers  at  the  University  Press,  Oxford,  by  Horace  Hart ;  and  my 
thanks  are  due  to  Messrs.  Richard  Clay  &  Sons,  the  printers,  for  carefully  carrying  out  my 
instructions. 

Last,  but  by  no  means  least,  I  wsli  to  say  that  the  pubUcation  of  this  work  \\ould  scarcely 
have  been  possible  without  the  wilhng  help  of  my  secretary.  Miss  E.  Messer.  In  addition  to  much 
other  onerous  work,  she  has  been  largely  responsible  for  the  correctness  of  the  Bibliographies  and 
references  in  the  text,  lias  proved  a  most  careful  and  efficient  proof-reader,  and  has  in  every  way  and 
at  all  times  done  all  that  was  possible  to  reheve  my  work  as  Editor  and  Contributor. 

NoKMAN  G.  Bennett. 
London,  IF. 

March  1914. 


TABLE  OF  CONTENTS 


CHAPTER  I 


Development  of  the  Jaws  and  Teeth  before  Birth 
Development  of  the  Visceral  Arches 
Development  of  the  Teeth        .... 
Ossification  and  Growth  of  tlie  Jaws 

Development  of  the  Jaws  .\nd  Teeth  after  Birth 
First  Dentition. — Eruption  of  the  Teetli 
Theories  .... 

Dates  .... 

Diseases  associated 
Development  of  the  Jaws  and  Teetli 
Absorption  of  the  Teeth 
Second  Dentition. — Eruption  of  the  Teeth 
Development  of  the  Jaws  and  Teeth 


CHAPTER  II 

Affections  assocl\ted  w- ith  the  Third  Mandibular  Molar 
Anatomical  Relations      ...... 

The  State  of  Eruption  of  tlie  Tootli 

Mode  and  Sjinptoms  of  Infection      .... 

Treatment  ....... 


PAGE 

1 

1 

U 

12 

15 
15 
15 
18 
19 
23 
27 
.  28 
29 


33 
33 
34 
34 
37 


CHAPTER  III 


Abnormalities  of  Size,  Number,  Form,  and  Structure 
Abnormalities  of  the  Permanent  Teeth 

Size 

Number 

Absence 
Excess    . 

Form    . 

Maxillary  Teeth 

Mandibular  Teeth 
Abnormalities  of  the  Deciduous  Teeth 

Size       .... 

Number 

Form 

Gemination 
Abnormalities  of  Structure     . 

Hypoplasia  of  Malnutrition 

Hypoplasia  of  Local  Origin 

Hypoplasia,  Congenital 


38 
38 
38 
38 
39 
40 
40 
41 
42 
43 
43 
43 
45 
45 
46 
47 
48 
49 


CHAPTER   IV 

ABNORM-ALrriES    OF    POSITION    OF   THE    TEETH    AND    ABNORMAL   DEVELOPMENT    OF  THE    ASSOCIATED    PaRTS 

Occlusion 

(Jrowth  of  the  .Jaws 

Aetiological  FacU)rs 

Heredity 

Environment 

Pathological  Influences 


52 
52 
55 
68 
68 
75 
75 


X  CONTENTS 

CHAPTER  V 

PAQE 

Abnobmautdes  of  Position  (continued)        ............        82 

Classification  ...............82 

Consideration  of  Different  Types      ............       84 

Causation. 

Principles  of  Treatment. 
Deciduous  Dentition  Abnormalities  .  .  .  .  .  .  .  .  ■  .  .135 

CHAPTER  VI 

ABNORMAiiTiES  OF  POSITION  (continued)         ............      143 

Diagnosis       ..........•..•••      143 

General  Objects  of  Treatment         ............      145 

Estimation  of  Arch  ..........■■•■      145 

Extraction  and  Mechanical  Treatment       ...........      147 

Complications  caused  by  Caries         .  .  .  .  .  •  •  •  •  •  •  .148 

Age  for  Mechanical  Treatment  ............      149 

Principles  of  Retention  .  .  .  .  .  .  •  •  •  •  •  .150 

Mechanics  and  Physiology  of  Tooth  Movement         .  .  .  .  ■  •  ■  •  .150 

Anchorage       .,..,......••■■      154 

Reciprocal  Action    ..............      156 

Preliminaries  of  Treatment       .............      159 

Care  of  the  Mouth  and  Appliances    .  .  .  .  .  .  .  •  .  .  ■  .160 

Surgical  Treatment  ..............      161 

CHAPTER  VII 

Abnobmauties  OF  Position — Treatment .      167 

Treatment  by  Means  of  Appliances  .  .  .  .  .  .  .  .  .  •  .167 

Tooth  Movement  ...,......,,..      181 

Major  Tooth  Movements  ............      183 

CHAPTER   VIII 

Abnormaiities  of  Position — Treatment  (continued)  .........     204 

Individual  Tooth  Movements  ............      204 

Treatment  by  Appliances. 


CHAPTER 

Abnormalities  of  Position — Treatment  (continued) 
The  Head-gear  and  Traction  Bar     . 
The  Movement  of  the  Roots  of  Teeth 
Force  as  Regards  the  Movement  of  Teeth 
Technique  of  Orthodontics 
The  Construction  of  Appliances 


IX 


216 
216 
217 
221 
222 
225 


CHAPTER 

Abnobmauties  of  Position — Treatment  (continued) 

Retention  ....... 

The  Treatment  of  Particular  Cases 


227 
227 
239 


CHAPTER   XI 

Saliva   and   CALCtTLus        ...............  247 

Constitution  of  the  Saliva  in  Health  and  Disease        .........  248 

Chemiotaxis  ...............  249 

Calculus  or  Tartar  ..............  250 

Calculus  in  Salivary  Ducts  and  Glands       ...........  253 

Discolorations  of  Teeth  due  to  External  Deposit         .........  254 


CONTENTS 
CHAPTER  XII 


Thk  Bacteria  of  the  JIouth 
Cocci 
BacUli 
Spirilla 
Streptothricao 
Blastomyces 
Leptothricae 


XI 


PAGE 

256 
269 
266 
273 

277 
278 
280 


CHAPTER   XIII 

The  Aetiology  of  Dental  Caries    .........•■••  282 

Chemistry     ..........•••-•■  282 

Diet 285 

Civilization  ........■••■•••■  287 

Race  ........■■■•■■■■  288 

The  Chemical  Constitution  of  the  Teeth  .......•■■  289 

The  Influence  of  the  Saliva  291 

Susceptibility  and  Immunity  ........•■■•  292 

Relative  Liability  of  Diiferent  Teeth  to  Caries   .......•■•  293 


CHAPTER   XIV 

The  Pathology  of  Dental  Caries  ............  295 

Microscopical  Phenomena  .........•••  296 

Micro-organisms     ........•••■•■■  299 

"Arrested"  Caries  ...........•■•  302 

Caries  in  Unusual  Situations  ............  303 


CHAPTER   XV 

The  Pathology  of  Erosion,  Attrition,  and  Abrasion 


304 


CHAPTER   XVI 

Diseases  of  the  Dental  Pulp    ..............     306 

Aetiology       ................      306 

Hyperaemia  .  .  .  .  .  .  .  .  .  .  •  •  .312 

Inflammation  ...........••■•      313 

Retrogressive  Changes  in  the  Pulp    .  .  .  •  •  •  •  •  •  •  •  .316 

The  Degenerations  ,..........••      317 

Calcification  or  Calcareous  Infiltration        ..........      318 

Necrosis  and  Putrefaction         ............      320 


CHAPTER  XVII 


The  Dental  Operating  Room    . 

Its  Appointments  and  Hygiene 


322 
322 


CHAPTER   XVIII 

Oral  Hygiene  and  Prev'entive  Treatment  of  Dental  Caries 
Natural  Means  of  Cleansing     ..... 

Artificial  Moans  of  Cleansing    ..... 

Periodical  Cleansing        ...... 

Treatment  ........ 


328 
329 
330 
333 
334 


Xll 


CONTENTS 


CHAPTER   XIX 

Treatment  of  Cavities  in  the  Teeth  by  Filung 
Examination  of  the  Mouth  and  Teeth 
Exclusion  of  SaKva        .... 

Separation     ...... 

General  Principles  of  Cavity  Preparation  . 
Sensitive  Dentine  and  the  Avoidance  of  Pain 
Objects  and  Intentions  of  Tooth  Restoration 
Filling  Materials 

Gold 

Tin 

Amalgams 

Cements 

Inlays     . 

Gutta-percha 
The  Appropriate  Filling  in  Cavities  of  Various  Degrees  in  Different  Teeth  at  Different  Ages 


PAGE 

336 
336 
337 
343 
344 
346 
348 
356 
356 
357 
357 
359 
360 
360 
361 


CHAPTER   XX 


Antiseptic  Technique  in  Dental  Surgery 
Dressings  and  Temporary  Fillings     . 


363 
368 


CHAPTER   XXI 


The  Manipulation  of  Gold 


370 


CHAPTER  XXII 


Filling  with  Foil     ...... 

Suitable  Cavities     ..... 

Unsuitable  Cavities  .... 

Special  Requirements  in  the  Form  of  Cavities 
Hints  on  working  Gold 


374 
374 
375 
375 
380 


CHAPTER   XXIII 


Plastic  Fillings        .  .  . 

Dental  Amalgams 
Osteo-plastic  Cements 
Gutta-percha  Compoimds 


386 
386 
397 
401 


CHAPTER  XXIV 


PoRCEL.iiN  Inlays 

Cavity  Preparation 

Making  of  Inlays    . 

Making  of  a  Fused  Inlay 

Retention 

Fixing  of  the  Inlay 


404 
405 
408 
414 
419 
420 


CHAPTER  XXV 


Gold  Inlays     ........... 

422 

Suitable  Cavities               ........ 

424 

Obtaining  the  Wax  Model         ....... 

430 

Methods  of  Casting  under  Pressui'e   ...... 

432 

Retention       .......... 

433 

Insertion  and  Cementation      ....... 

433 

CONTENTS 
CHAPTER   XXVI 


DiAONOSIS    OF   THE    CaUSE    OF    PaIN 

Odontalgia  and  Neuralgia 
Aids  to  Diagnosis 
Head's  Areas 


XIU 


PAGE 

435 
436 
443 

444 


CHAPTER   XXVII 

Treatment  of  the  Dental  Pulp       ......... 

Management  wlien  almost  exposed  ....... 

Devitalization         ........... 

Conditions  requiring  Devitalization  of  the  Dental  Pulp       .... 

Removal  of  Pulps  .......... 

Management  of  Root-canals  of  Teeth  having  Dead  Pulps     .... 

Devitalization  and  Management  of  Pulp  and  Root-canals  of  Deciduous  Teetli 
Filling  Root-canals         .  ......... 

Selection  of  Materials        ......... 


451 
451 
454 
461 
465 
471 
474 
474 
478 


CHAPTER   XXVIII 


The  Treatment  of  Children  and  Chtldren's  Teeth 
Prevention  of  Dental  Disease   . 
Treatment     ...... 


483 
483 

484 


CHAPTER   XXIX 


Diseases  of  the  Periodontal  Membrane 
Anatomy 

Acute  Local  Periodontitis 
Chronic  Local  Periodontitis 
Productive  Periodontitis 
Anchylosis 

Rarefying  Periodontitis 
Necrosis  of  Teeth 
General  Periodontitis 


487 
487 
488 
491 
492 
495 
497 
499 
500 


CHAPTER   XXX 


Diseases  of  the  Periodontal  Membrane  (continued) 
Chronic  Suppurative  Periodontitis    . 


502 
502 


CHAPTER   XXXI 


Dental  Electro-therapeutics 
Apparatus 
Cataphoresis 
Ionic  Medication     . 
Treatment 


514 
514 
519 
519 
520 


CHAPTER   XXXII 


Injuries  of  the  Teeth  due  to  Violence 

Concussion    .  .          .          .          . 

Dislocation    .  .          .          .          . 

Fracture         .  .           .           .           . 


524 
524 
524 

526 


XIV 


CONTENTS 


CHAPTER   XXXIII 

PAGE 

The  Mechanical  Stresses  of  Mastication        ...........  529 

In  Normal  Arches  and  under  Normal  Conditions       .........  529 

Under  Abnormal  Conditions     .............  531 

In  Relation  to  Bridge-work     .............  534 


CHAPTERS   XXXIV  to   XXXVI 


Artificial  Crowns    ...... 

General  Considerations   .... 

Roots  suitable  for  Crowns 

Principles  of  Crowning    .... 

Various  Types  of  Crowns  considered  in  Detail 

Replacing  Porcelain  Facings    . 

Partial  Crowns       ..... 

Fixing  Crowns       ..... 


537 
537 
539 
540 
559 
590 
596 
597 


CHAPTERS   XXXVII   to   XXXIX 


Bbidqe-work    ....... 

Selection  of  Cases  and  General  Considerations 
Impressions  ....... 

Description  of  Making  a  Fixed  Bridge 
Descrip'^ion  of  Making  a  Removable  Bridge 
Abutments  for  Removable  Bridges 
Saddle  Bridges 
Pressure- Casting     . 
Cementing  of  Bridges 
Repairing  Bridges 
Porcelain  Bridges  . 
Cast  Sectional  Bridges 


602 
602 
606 
608 
617 
620 
623 
625 
626 
626 
628 
631 


CHAPTER   XL 


Extraction  of  Teeth        ........ 

640 

General  Principles             ....... 

641 

The  Operation        ........ 

642 

Difficulties     ......... 

655 

Accidents       ......... 

657 

Sequels          ......... 

658 

CHAPTER  XLI 


Local  Anaesthesia 


664 


CHAPTER   XLII 


Alveolar  Abscess     ...... 

Course  and  Pathology     .... 

Clinical  Course  and  Signs  of  Acute  Abscess 
Clinical  Course  and  Signs  of  Chronic  Abscess 
Rarer  Forms  of  Chronic  Abscess 
Treatment     ...... 

Sequelae    ...... 


671 
671 
672 
673 
674 
674 
676 


CONTENTS 
CHAPTER   XLIII 


XV 


PAQB 

Empyema  of  the  Maxillary 

Sinus     ....... 

678 

Dental  Causes 

678 

Traumatic  Causes 

. 

679 

Acute  Inflammation 

680 

Clironic  Empyema 

. 

682 

CHAPTER   XLIV 

Necrosis  of  the  Jaw       ...............  687 

Causes  ................  687 

Treatment 689 


CHAPTER   XLV 


Fractures  of  the  Jaws 

Mandible 

Causes 

Signs  and  Symptoms 

Displacement 

Complications 

Treatment 

Maxilla 
Dislocation  of  the  Mandible 


690 
690 
690 
691 
691 
692 
692 
698 
699 


CHAPTER  XLVI 

Oral  Sepsis       .................      701 

Diseases  associated  with  Chronic  Septic  Processes  in  the  Mouth   .......      702 

CHAPTER   XLVII 

Dental  Radiography  ...............      712 

Film  Radiograplis  in  the  Mouth       .  .  .  .  .  .  .  .  .'.  .  .713 

Stereoscopes  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .714 

Diagnosis  by  means  of  X-rays  .  .  .  .  .  .  .  .  .  .  .  .716 

CHAPTER   XLVIII 

Reflex  Affections  Due  to  Diseased  Teeth      ...........      727 


CHAPTER  XLIX 

Diseases  of  the  Mucous  Membrane  of  the  Mouth — Immobility  of  the  Mandible 


736 


CHAPTER  L 

Odontomes        .................  740 

Classification           ...............  741 

Diagnosis       ................  762 

CHAPTER  LI 

Actinomycosis  or  Streptothricosis   ...........'..  767 

Course,  Pathology,  and  Symptoms              ...........  767 

Treatment     ................  770 


APPENDIX 


Dental  Jurisprudence      .... 
The  Dentist  and  the  State 
The  Dentist  and  the  Lay  Public      . 
The  Dentist  and  his  Fellow  Practitioners 

Index      ........ 


771 
771 

777 
782 

787 


CONTEIBUTORS 

A.  W.  W.  BAKER,  A.B.,  M.D.,  M.Ch.  Dub.,  F.R.C.S.I.,  L.D.S.I.,  M.Dent.  Sc.  Dub.  (hon.  causa)  ; 
Consulting  Dentist,  Royal  Victoria  Eye  and  Ear  Hospital;  Dentist,  Incorporated  Dental 
Hospital,  Ireland ;  University  Examiner  in  Dental  Surgery,  Trinity  College,  Dublin ;  late 
Examiner  in  Dental  Surgery,  R. C.S.I. 

Diagnosis  of  the  Cause  of  Pain Chapter  XXVI,  pp.  435-50 

H.  BALDWIN,  M.R.C.S.,  L.D.S.  Eng.  ;    late  Assistant  Dental  Surgeon,  Royal  Dental  Hospital, 

London. 

Artificial  Crowns Chapters  XXXIV— XXXVI,  pp.  537-601 

NORMAN  G.  BENNETT,  M.A.,  M.B.,  B.C.  Cantab.,  L.D.S.  Eng.  ;    Dental  Surgeon,  St.  George's 
Hospital  and  Royal  Dental  Hospital,  London  ;  Member  of  the  Board  of  Examiners  in  Dental 
Surgery,  R.C.S.  Eng. ;  late  External  Examiner  in  Dentistry,  University  of  Birmingham. 
Abnormalities  of  Position  of  the  Teeth,  and  Abnormal  Development  of  the  Associated  Parts 

Chapters  IV— VI,  pp.  52-166 
Fractures  and  Dislocation  of  the  Jaws Chapter  XLV,  pp.  690-700 

G.  G.  CAMPION,  L.D.S.  Eng.  ;    Dental  Surgeon,  Dental  Hospital  of  Manchester;    Lecturer  on 

Orthoilontics,  ^'l(•toria  L^niversitv  of  Manchester. 

The  Mechanical  Stresses  of  Mastication,  jointly  with  C.  H.  PRESTON  {see  below) 

Chapter  XXXIII,  pp.  529-36 

HAROLD  CHAPMAN,  L.D.S.  Eng.,  D.D.S.  Penn. ;  Dental  Surgeon,  London  Hospital,  and  Lecturer 
on  Udunto-prosupic  Orthopaedics,  London  Hospital  Dental  School. 

Treatment  of  Abnormalities  of  Position  of  the  Teeth       .         .         .       Chapters  VII — X,  pp.  167-246 

C.  A.  CLARK,  L.D.S.I.  ;  Radiographer,  Royal  Dental  Hospital,  and  National  Dental  Hospital, 
London. 

Dental  Radiography Chapter  XL VI,  pp.  712-26 

FRANK  COLEMAN,  L.R.C.P.  Lond.,  M.R.C.S.,  L.D.S.  Eng.  ;  Assistant  Dental  Surgeon,  St. 
l)arthol(jnie\v's  llos])ital  and  Royal  Dental  Hospital,  London. 

The  Development  of  the  Jaws  and  Teeth       .......     Chapter  I,  pp.  1 — 32 

STANLEY  COLYER,  M.D.,  M.R.C.P.  Lond. 

Oral  Sepsis Chapter  XL VI,  pp.  701-11 

E.   B.   DOWSETT,  L.R.C.P.   Lond.,  M.R.C.S.,   L.D.S.   Eng.  ;    Assistant  Dental  Surgeon,   Guy's 

lliis|iitai.  and  Demonstrator  of  Dental  Histology,  Guy's  Hospital  Dental  School. 

Oral  Hygiene  and  Preventive  Treatment  of  Dental  Caries         .         .         .   Chapter  XVIII,  pp.  328-35 

DOUGLAS  P.  GABELL,  L.R.C.P.  Lond.,  M.R.C.S.,  L.D.S.  Eng.  ;  Dental  Sui'geon  and  Lecturer  on 
Dnital  .Mechanics,  Royal  Dental  Hospital,  London:  late  External  Examiner  in  Dentistry, 
Victoria  University  of  Manchester, 

Abnormalities  of  Size,  Number,  Form,  and  Structure  of  the  Teeth,  jointly  with  A.  LANDON 

WHITEHOUSE  {see  ielow) Chapter  III,  pp.  38-51 


xviii  CONTRIBUTORS 

KENNETH  W.  GOADBY,  L.R.C.P.  Lond.,  M.R.C.S.,  L.D.S.  Eng.,  D.P.H.  Cantab.  ;  Pathologist 
and  Lecturer  on  Bacteriology,  National  Dental  Hospital ;  Dental  Surgeon,  Seamen's  Hospital 
Society,  and  Lecturer  on  Oral  Hygiene,  London  School  of  Tropical  Medicine;  John  Tomes 
Prizeman,  Erasmus  Wilson  Lecturer,  and  Hunterian  Professor,  R.C.S.  Eng. 

The  Bacteria  of  the  Mouth Chapter  XII,  pp.  256-81 

W.  C.  GOWAN,  D.D.S.  Chicago,  L.D.S.  Ontario. 

Filling  with  Foil Chapter  XXII,  pp.  374-85 

Gold  Inlays Chapter  XXV,  pp.  422-34 

WILLIAM  GUY,  L.R.C.P.,  F.R.C.S.,  L.D.S.  Edin.,  F.R.S.E.  ;  Consulting  Dental  Surgeon,  Royal 
Infirmary,  Edinburgh ;  Dean,  and  Lecturer  on  Dental  Anatomy  and  Physiology  and  Dental 
Histology,  Edinburgh  Dental  Hospital ;    Examiner  in  Dentistry,  R.C.S.  Edin. 

Extraction  of  Teeth Chapter  XL,  pp.  640-63 

P.  B.  HENDERSON,  B.A.  Oxon  ;   Solicitor  of  the  Supreme  Court. 
Dental  Jurisprudence Appendix,  pp.  771-86 

W.  ARCHER  HODGSON,  L.D.S.  Eng.  ;  Demonstrator  of  Practical  Dentistry,  Guy's  Ho.spital 
Dental  School. 

Diseases  of  the  Periodontal  Membrane  (Chronic  Suppurative  Periodontitis)     Chapter  XXX,  pp.  502-13 

A.  HOPEWELL-SMITH,  L.R.C.P.  Lend.,  M.R.C.S.,  L.D.S.  Eng.  ;  Dental  Surgeon  and  Lecturer 
on  Dental  Anatomy  and  Physiology,  Royal  Dental  Hospital,  London ;  John  Tomes  Prize- 
man, R.C.S.  Eng. ;  External  Examiner  in  Dentistry,  Universities  of  Leeds  and  Liverpool ; 
late  External  Examiner  in  Dentistry,  University  of  Birmingham. 

The  Pathology  of  Dental  Caries Chapter  XIV,  pp.  295-303 

The  Pathology  of  Erosion,  Abrasion  and  Attrition           ....  Chapter  XV,  pp.  304-5 

Diseases  of  the  Dental  Pulp Chapter  XVI,  pp.  306-21 

MONTAGU  F.  HOPSON,  L.D.S.  Eng.  ;  Dental  Surgeon,  Guy's  Hospital,  and  Lecturer  on  Dental 
Anatomy  and  Physiology,  Guy's  Hospital  Dental  Scliool ;  Member  of  the  Board  of  Ex- 
aminers in  Dental  Surgery,  R.C.S.  Eng. ;  External  Examiner  in  Dentistry,  University  of 
Birmingham. 

Plastic  Fillings Chapter  XXIII,  pp.  386^03 

Injuries  of  the  Teeth  due  to  Violence    ......  Chapter  XXXII,  pp.  524-8 

EDWIN  HOUGHTON,  L.D.S.I. 
Cast  Sectional  Bridge-work Chapter  XXXIX,  pp.  631-9 

W.  WARWICK  JAMES,  L.R.C.P.  Lond.,  F.R.C.S.,  L.D.S.  Eng.  ;  Assistant  Dental  Surgeon,  Middle- 
sex Hospital ;  Assistant  Dental  Surgeon  and  Lecturer  on  Operative  Dental  Surgery,  Royal 
Dental  Hospital,  London. 

Serious  Affections  Associated  with  the  Third  Mandibular  Molar        .         .         .     Chapter  II,  pp.  33-7 

Odontomes  Chapter  L,  pp.  740-66 

Actinomycosis Chapter  LI,  pp.  767-70 

GEORGE  NORTHCROFT,  L.D.S.  Eng.,  D.D.S.  Mich.  ;  Dental  Surgeon,  London  Hospital,  and 
Lecturer  uu  Ojn.Tative  Dental  Surgery,  London  Hospital  Dental  School. 

The  Treatment  of  Children  and  Children's  Teeth     ....  Chapter  XXVIII,  pp.  483-6 


CONTRIBUTORS  xix 

J.  B.  PARFITT,  L.R.C.P.  Lond.,  M.R.C.S.,  L.D.S.  Eng.  ;    Dental  Surgeon,  Guy's  Hospital,  and 

Lecturer  on  Operative  Dental  Surgery,  Guy's  Hospital  Dental  School. 

The  Denial  Operating  Room,  Its  Appointments  and  Hygiene    .  Chapter  XVII,  pp.  322-7 

The  Manipulation  of  Gold Chapter  XXI,  pp.  370-3 

Porcelain  Inlays Chapter  XXIV,  pp.  404-21 

J.  LEWIN  PAYNE,  L.R.C.P.  Lend.,  IM.R.C.S.,  L.D.S.  Eng.  ;  Assistant  Dental  Surgeon,  Guy's 
Hospital,  and  Lecturer  on  Dental  Mechanics,  Guy's  Hospital  Dental  School. 

Diseases  of  the  Periodontal  Membrane Chapter  XXIX,  pp.  487-501 

FRANK  J.  PEARCE,  L.D.S.  Eng..  D.D.S.  Penn.  ;   Assistant  Dental  Surgeon,  Guy's  Hospital,  and 

Demonstrator  of  Practical  Dental  Metallurgy,  Guy's  Hospital  Dental  School. 

Local  Anaesthesia      ..........       Chapter  XLI,  pp.  664-70 

H.  PERCY  PICKERILL,  M.D.,  B.Ch.,  M.D.S.  Birm.,  L.D.S.  Eng.  ;  Professor  of  Dentistry  and 
Director  of  Dental  School,  University  of  Otago ;  Hon.  Stomatologist,  Dunedin  Hospital ; 
Cartwright  Prizeman,  R.C.S.  Eng. ;  Examiner  in  Dental  Surgery,  LTniversity  of  New  Zealand. 

Antiseptic  Technique  in  Dental  Surgery — Dressings  and  Temporary  Fillings 

Chapter  XX,  pp.  363-9 
Reflex  Affections  due  to  Diseased  Teeth Chapter  XLVIII,  pp.  727-35 

G.  PATON  POLLITT,  L.D.S.  Eng.,  D.D.S.  Penn.  ;  Dental  Surgeon,  London  Hospital,  and  Lecturer 
on  Operative  Dental  Prosthesis,  London  Hospital  Dental  School. 

Bridge-work Chapters  XXXVII  and  XXXVIII,  pp.  602^0 

C.  H.  PRESTON,  M.D.,  B.S.  Lond.,  B.Sc.  Vict.,  L.R.C.P.  Lond.,  F.R.C.S.,  L.D.S.  Eng.  ;  Surgeon 
aud  Tutor,  Victoria  Dental  Hospital,  Manchester;  Lecturer  on  Dental  Anatomy,  Victoria 
University  of  Manchester. 

Saliva  and  Calculus Chapter  XI,  pp.  247-55 

The  Mechanical  Stresses  of  Mastication,  jointly  with  G.  G.  CAMPION  (see  above) 

Chapter  XXXIII,  pp.  529-36 

W.  G.  T.  STORY,  M.B.,  B.A.O.,  B.Ch.,  D.P.H.  Dub.,  L.D.S.I.  ;  Dental  Surgeon,  Dental  Hospital 
of  Ireland;   Examiner  in  Dental  Surgery,  R.C.S. I. 

Treatment  of  Cavities  in  the  Teeth  by  Filling Chapter  XIX,  pp.  348-62 

ERNEST  STURRIDGE,  L.D.S.  Eng.,  D.D.S.  N.Y. 

Dental  Electro-Therapeutics Chapter  XXXI,  pp.  514-23 

HERBERT  TILLEY,  M.D.,  B.S.  Lond.,  F.R.C.S.  Eng.  ;  Surgeon,  Ear  and  Throat  Department, 
University  College  Hospital;  Lecturer  on  the  Diseases  of  the  Ear,  Nose,  and  Throat,  Royal 
Army  iledical  College ;   Larjiigologist,  Radium  Institute. 

Empyema  of  the  Maxillary  Sinus Chapter  XLIII,  pp.  678-86 

J.  G.  TURNER,  L.R.C.P.  Lond.,  F.R.C.S.,  L.D.S.  Eng.  ;    Dental  Surgeon  and  Lecturer  on  Dental 
Surgery,  Royal  Dental  Hospital,  London. 

Alveolar  Abscess Chapter  XLII,  pp.  671-7 

Necrosis  of  the  Jaws Chapter  XLIV,  pp.  687-9 

Diseases  of  the  Mucous  Membrane  of  the  Mouth — Immobility  of  the  Mandible 

Chapter  XLIX,  pp.  736-9 

J.  SIM  WALLACE,  M.D.,  CM.,  D.Sc,  Glas.,  L.D.S.  Eng. ;   Dental  Surgeon,  West  End  Hospital 

for  Nervous  Diseases. 

The  Aetiology  of  Dental  Caries Chapter  XIII,  pp.  282-94 


XX  CONTRIBUTORS 

A.  E.  WEBSTER,  M.D.,  D.D.S.  Chicago,  L.D.S.  Ontario;   Professor  of  Operative  Dentistry  in  the 

School  of  the  Royal  College  of  Dental  Surgeons  of  Ontario. 

Treatment  of  the  Dental  Pulp Chapter  XXVII,  pp.  451-82 

A.  LANDON  WHITEHOUSE,  L.R.C.P.  Lond.,  M.R.C.S.,  L.D.S.  Eng.  ;  Dental  Surgeon,  Royal 
Waterloo  Hospital  for  Women  and  Children ;  Assistant  Dental  Surgeon,  Royal  Dental 
Hospital,  London. 

Abnormalities  of  Size,  Number,  Form  and  Structure  of  the  Teeth,  jointly  with  DOUGLAS  P. 

GABELL  {see  above) Chapter  III,  pji.  38-51 

J.  A.  WOODS,  M.D.S.  Liver.,  L.D.S.  Eng.  ;  Hon.  Dental  Surgeon,  Dental  Hospital,  Liverpool ; 
Lecturer  on  Dental  Anatomy  and  Physiology  and  Demonstrator  of  Dental  Histology,  and 
Internal  Examiner,  University  of  Liverpool;  External  Examiner  in  Dentistry,  Victoria 
University  of  Manchester. 

Treatment  of  Cavities  in  the  Teeth  by  Filling Chapter  XIX,  pp.  336-48 


CHAPTER    I 


THE  DEVELOPMENT  OF  THE  JAWS  AND  TEETH 


A.  DEVELOPMENT  OF  THE  JAWS  AND 
TEETH  BEFORE  BIRTH 

1.  Development  of  the  Visceral  Arches. — The 
period  of  human  crestatioii  has  been  arbitrarily 
divided  into  three  stages — 

(1)  Tlie  pre-embryo- 

nic,  or  stage  of 
the  zygote, 
comprising  the 
fii'st  two  weeks 
of  develop- 
ment. 

(2)  The  stage  of  tlie 

embryo,  ex- 
tending from 
the  end  of  tlie 
second  week  to 
the  end  of  tlie 
second  month, 
during     Mhicli 


During  the  third  period,  or  stage  of  the  foetus, 
the  earliest  indications  of  tooth  formation 
appear ;  while  during  the  second  period  the 
earliest  indications  of  a  mouth  can  be  detected, 
together  with  the  subsequent  changes  that 
lead  to  the  formation  of  the  jaws.     The  first 


Fig. 


-Showing  segmentation  of  the  fertiUzed  oviun  or  zygote  in  the  rabbit 
(from  Cunningham). 


time  the  zygote     ^'  Division  into  two  segments;    B,  Division  into  four  segments;   C,   Division  into 
•'S  .  severalsegments  (morula) ;   P,  Polar  bodies  (minute  portions  of  the  egg  substance, 


begins  to 
assume  definite 
human  characteristics 

V 


VM- 


Nll 


Fig.  1. — Tlie  ovimi  with  its  coverings  partly  shown 
(from  Cunningham).     (Diagrammatic.) 

C,  Corona  radiata  ;  G,  Granular  layer ;  Z,  Oolemma  (Zona 
pellucida);  VJI,  Vitelline  membrane;  V,  Vitellus 
or  yolk ;  NM,  Nuclear  membrane ;  GV  Nucleus 
(Germinal  vesicle) ;  GS,  Nucleolus  (Germinal  spot). 

(3)  The  stage  of  the  foetus,  which  includes  the 
remainder  of  the  term  of  intra-uterine 
existence. 
1 


containing  nucleus  and  yolk,  budded  off  from  the  zygote). 

period,  or  stage  of  the  zygote,  is  not  directly 
concerned  in  tooth  or  jaw  formation,  but  only 
in  the  preparation  for  such,  by  a  laying  down 
of  the  '■  ground-work  "'  and  differentiation  of 
the  ceUs  into  ectodermic,  mesodermic,  and 
entodermic,  from  which  are  evolved  the  axial 
and  ajipendicular  skeleton  with  the  contained 
viscera. 

The  development  of  the  teeth  camiot  be 
rendered  intelligible  unless  it  is  preceded  by  an 
outline  of  the  development  of  the  jaws  as  a 
whole.  The  earliest  indication  of  a  mouth 
can  be  detected  at  the  twelfth  day  of  intra- 
uterine life ;  before  this  the  zygote  has  passed 
through  the  stage  of  the  ovum  (see  Fig.  1) 
with  its  fertilization  and  segmentation  followed 
by  its  morula  and  vesicular  forms  (see  Figs. 
2,  3),  the  development  of  the  embryonic 
area  (see  Pig.  4),  and  the  commencement 
of  differentiation  of  its  cells  into  ectoderm, 
mesoderm,  and  entoderm  (see  Figs.  5,  6,  7). 
The  primitive  mouth  or  stomatodaeuni,  as 
it  is  then  termed,  consists  of  superimposed 
layers  of  ectoderm  and  entoderm  (oral  plate), 
situated  in  a  depression  (oral  pit)  bounded 
by  two  prominences.  The  prominence  in  front 
of  the  oral  plate  is  produced  by  an  enlarge- 
ment of  the  cephalic  or  head  end  of  the  neural 


tube  to  form  the  cerebral  vesicles,  and  the 
prominence  behind  the  oral  plate  arises  from 
the  development  of  the  visceral  arches  (see 
Fig.  8).  The  oral  pit,  stomatodaeum,  or  future 
mouth,  becomes  deejDened  by  the  growth  of 
these  prominences  and  by  the  downward  folding 
of  the  anterior  prominence  or  fore-brain  vesicle ; 
so  that  the  stomatodaeum  comes  to  occupy  a 


its  floor  is  formed  by  the  oral  plate,  or  meeting 
of  the  surface  ectoderm  with  the  entoderm  of 
the  primitive  fore-gut  (see  Figs.  5,  8).  The 
oral  plate,  whicli  is  later  known  as  the  bucco- 
pharyngeal membrane,  forms  a  partition  between 
the  primitive  oral  cavity,  or  stomatodaeum, 
and  the  fore-gut,  and  disappears  about  the 
third    week,    thus    bringing    the    mouth    into 


A 


Trophoblast. 


B 


Trophobla&t. 

Amniotic 
ectoderm. 

-j^ —  Ectomesoderm, 

-lA Embryonic 

entoderm. 
.Extra-embryo- 
nic entoderm. 

Primary 
mesoderm. 


Amnion  cavity. 

Primitive 
alimentary  canal 
Extra-embryonic 
coelom. 


D 


plasmodial  trophoblast. 

Cellular  trophoblast. 
Amniotic  ectoderm. 


Embryonic 
ectomesoderm 

Embryonic  entoderm. 

Extra-embryonic 
entoderm. 

Primary  mesoderm. 


Plasmodial  trophoblast. 

Cellular  trophoblast. 

Amniotic  ectoderm. 

Embryonic 
ectomesoderm. 
i;inbryonic  entoderm 

.Extra-embryonic 
entoderm. 

Primary  mesoderm. 


Fig.  3. — Differentiation  of  the  morula  and  the 
formation  of  the  amnion,  yolk,  and  coelomic 
cavities  (after  Cunningham). 

A,  Showing  outer  layer  of  cells  (trophoblast),  and 

inner  mass  of  cells,  which  have  now  separ- 
ated into  three  groups,  viz.  ectoderm,  ento- 
derm, and  primary  mesoderm.     The  darker 

shaded   cells    of   the   inner  mass   are   those  i^'   -  - 

from  which  the  embryo  will  be  formed. 
In  some  mammals  a  cavity  (segmentation 
cavity)  replaces  the  space  occupied  by  the  cells  of  the  primary  mesoderm. 

B,  Showing  further  differentiation  of  the  cells  of  the  inner  mass.     The  primary  mesoderm  has  proliferated  still 

further,  and  now  separates  the  cells  of  the  inner  mass  from  the   outer  layer  of  cells  (trophoblast)  except 
in  the  embryonic  region  of  the  zygote. 

C,  Showing   the   ectomesodermal   and    entodermal   portions   of   the   inner  mass   assuming  the  form  of  hoUow 

vesicles  owing  to  the  formation  of  cavities  in  their  substance.     The  darker  shaded  cells  of   the  vesicles 
where  they  he  in  apposition  indicate  the  situation  at  which  the  embryo  will  be  formed. 

D.'Showing  enlargement  of  the  vesicles  to  form  respectively  the  amnion  cavity  and  the  yolk  sac,  from  the 
latter  of  which  the  aUiuentary  canal  is  separated  off.  The  appearance  of  the  extra-embryonic  coelom  in 
the  primary  mesoderm  around  the  embryonic  area  is  indicated.  The  coelomic  cavity  increases  in  size 
at  the  expense  of  the  primary  mesoderm  until  the  latter  merely  forms  a  thin  layer  lining  the  trophoblast  and 
covering  the  extra-embryonic  portions  of  the  ectomesodermal  and  entodermal  vesicles.  In  the  human 
subject  a  small  portion  of  primary  mesoderm  surroimds  both  vesicles. 


position  in  front  of,  and  below,  the  bhnd  end 
of  the  primitive  fore-gut  (see  Figs.  5,   9). 

The  prominence  behind  the  oral  pit  is  further 
increased  by  the  development  of  the  heart,  on 
the  ventral  side  of  the  fore-gut  (see  Figs.  5,  8). 
Thus  the  oral  pit  is  at  first  bounded  in  front 
(cephalad)  by  the  prominence  of  the  fore-brain 
vesicle,  and  beliind  (caudad)  by  the  prominence 
formed  by  the  heart  and  the  visceral  arches,  and 


communication  with  the  upper  end  of  the  alimen- 
tary canal  (fore-gut),  and  with  the  respiratory 
passage,  which  develops  as  an  ofishoot  from 
the  fore-gut  (see  Fig.  8).  The  position  of  the 
bucco -pharyngeal  membrane  may  be  repre- 
sented in  the  adult  by  an  oblique  plane  extending 
from  the  roof  of  the  pharynx  to  the  front  of  the 
tongue  (see  Figs.  9,  24). 
During  the  third  week,  the  naso -frontal  or 


median  nasal  process  appears  as  a  thickening  on 
the  ventral  wall  of  the  fore-brain  vesicle  (see 
Fig.  11,  I  and  II);    growing   downwards  and 


Fig.  4. — Shuwiug  upper  pole  (i.  e.  embryonic  region)  of  the  blastodermic  vesicle 

in  a  ferret  (from  Cunningham).     {Diagrammatic.) 
A,  Surface  view.     B  and  C,  Transverse  sections  through  the  blastoderm  in  the 

region  of  lines  b  and  c  respectively. 
E,  Embryonic  area ;    P,  Primitive  streak ;    N,  Neural  groove ;  M,  Mesoderm  ; 

NO,  Notochord  ;  EP,  Ectoderm ;  H,  Entoderm. 

forwards  from  either  side  of  this  central  pro- 
minence are  the  lateral  nasal  processes.  The 
median  and  lateral  nasal  processes  together  now 
form  the  upper  boundary  of  the  oral  jjit,  the 
fissure  between  these 
prominences  forming  the 
nasal     pit,     or     future 

anterior  iiarLs.    The  oral  ^lu 

pit  is  bounded  below 
by  the  mandibular  pro- 
cesses and  laterally  by 
the  maxillary  processes, 
both  of  which  arise 
from  the  first  visceral 
arch.  The  fissure  be- 
tween the  maxiOary  and 
mandibular  processes 
forms  the  future  mouth, 
and  that  between  the 
maxillary  and  lateral 
nasal  processes  the  naso- 
orbital  sulcus,  or  future 
lacrimal  duct. 

During  the  fifth  week 
the  mandibular  pro- 
cesses unite  ventrally  to 
form  the  mandibular 
arch,  and  a  week  later 


process  are  formed  the  central  portions  of  the 
pre-maxillae  (endognathia),  or  that  portion 
carrying  the  central  incisor  teeth,  a  correspond- 
ing portion  of  the  upper 
lip,  and  the  septum  and 
bridge  of  the  nose.  From 
each  lateral  nasal  process 
are  formed  tlie  lateral  por- 
tion of  the  pre-maxilla 
(mesognathion),  or  that  por- 
tion carrying  the  lateral 
incisor  tooth,  a  correspond- 
ing portion  of  the  upper 
lip  (except  its  free  margin), 
and  the  ala  of  the  nose. 
These  processes,  with  the 
naso-frontal  process,  form 
the  OS  incisivum  (Albrecht) 
and  complete  the  anterior 
nares.  The  incisive  bone, 
according  to  Kolliker,  is 
formed  entirely  from  the 
naso-frontal  process. 

The  greater  portion  of 
the  maxiUa,  containing  the 
remaining  teeth  (exognathion),  results  from  a 
metamorphosis  of  the  maxillary  process.  The 
maxillary  process  likewise  forms  the  zygomatic 
and  palatine  bones,  a  corresponding  portion  of 

SpC 


-.EC 


BP 


SpM 


Soli 


Fig.  5. — Longitudinal  section  of  a  developing  ovum  about  the  end  of  the  second 
week  (from  Cunningham).  The  folding  off  of  the  embryo  has  commenced,  and 
the  downward  bend  of  the  head  fold  has  invaginated  the  amniotic  area. 
The  tail  fold  is  partly  formed,  and  the  primitive  alimentary  canal,  closed 
in  front  by  the  bucco-pharyngeal  membrane  and  behind  by  the  cloacal 
membrane,  is  distinguishable ;  it  communicates  freely  with  the  yolk  sac  by 
a  wide  umbilical  aperture, 
^t,";^!,  "+.ri.ra  -^hZc."~\^^  C,  Coelom;  EN,  Entoderm;  SoM,  Somatic  mesoderm;  EC,  Ectoderm;  M,  Moso- 
umon    takes     piace     oe-  derm ;  SpM,  Splanchnic  mesoderm  ;   BP,  Buoco-pharyngeal  membrane ;  PA. 

tween  the  naso-frontal,  ~        ■  ■        '     .r,    .__:_.■_  r_ij  .  ^»t,  t,:j  u..„:„.  c„,.    c.,:.,„i  — j.,ii~ . 

lateral  nasal,  and  maxil- 
lary  processes,    but    in 
such    a   way    that    the 
lateral  nasal  processes  fall 
share  in  the  formation  of 


Placental  area;  AF,  Amniotic  fold;  MB,  ilid-brain;  SpC,  Spinal  medulla; 
N,  Notochord ;  RS,  Rhomboidal  sinus ;  PS,  Primitive  streak ;  CM,  Cloacal 
membrane ;  H,  Heart. 


short  and  take  no 
the  free   margin  of 


the  lips  (see  Fig.    12).    From  the  naso-frontal 


the  lips  and  cheek,  and  by  means  of  its 
internal  or  lateral  prominence  the  future  palate 
(except  that  formed  by  the  pre-maxiUa),  thus 


closing  off  the  mouth  from  the  nose  (see  Fig.  13). 
The  mandibular  processes  form  the  mandible, 
the  lower  lip,  and  the  chin. 

The   fusion   of  the   internal   prominences  of 


Fig.  6. — Transverse  section  of  the  embryonic  area  of  the  oviun  of  a  sheep 
at  the  end  of  the  second  week  (after  Bonnet). 

pcj.  Primitive  groove ;  ps.  Primitive  streali ;  e.  Ectoderm ;  m.  Mesoderm ; 
pm.  Parietal  mesoderm;  c,  C'oelom  or  primitive  body  cavity;  vm. 
Visceral  mesoderm ;    h,  Entoderm ;    am.  Amnion  fold. 

the  maxillary  processes  commences  anteriorly 
at  the  eighth  week  and  is  completed  at  the 
eleventh  week. 

Failure  of  union  of  the  internal  maxillary 
prominences  results  in  a  cleft 
palate,  varying  in  extent 
from  a  bifid  uvula  to  a  cleft 
extending  to  the  anterior 
palatine  foramen,  or  junction 
of  the  maxiUae  and  pre- 
niaxillae.  If  the  naso-frontal 
process  on  tlie  medial  aspect 
and  the  lateral  nasal  and 
maxillary  processes  on  the 
lateral  aspect  also  fail  to 
coalesce,  the  cleft  will  extend 
forwards  to  one  or  other  side 
of  the  median  plane,  be- 
tween tlie  segments  of  the 
pre-maxilla  (?'.  e.  meso-  and 
endo-gnathion),  and  thus 
open  into  the  nostril.  The 
alveolar  portion  of  the  cleft 
will  pass  between  the  central 
and  lateral  incisor  teeth,  as 
these  are  developed  in  the 
endognathion  and  mesogna- 
thion  respectively  (see  Fig. 
14). 

The  discrepancy  in  opinion 
that  has  arisen  with  respect 
to   the  position   of  the   alveolar   cleft  may   be 
explained  by  the  occa.sional  development  of  a 
supenuimerary  tooth  in  the  endognathion  seg- 
ment and  the  absence  of  tooth  formation  in 


the  mesognathion  segment  (see  Fig.  15),  so 
tltat  the  supernumerary  tooth  is  mistaken  for 
the  lateral  incisor  and  the  cleft  is  consequently 
stated  to  pass  between  the  lateral  incisor  and 
canine.  Now  if  in  addition 
to  the  supernumerary  tooth 
a  lateral  incisor  is  formed  in 
the  lateral  nasal  process,  the 
latter  tooth  is  then  ingeni- 
ously called  a  pre-canine,  to 
avoid  designating  both  teeth 
as  lateral  incisors.  In  other 
words,  it  is  the  development 
of  the  teeth  that  is  subject 
to  variation  and  rarely  the 
position  of  the  cleft,  so  that 
when  the  teeth  are  normally 
developed  the  alveolar  cleft 
passes  between  the  central 
and  lateral  incisors. 

A   simple    or    incomplete 
hare-lip  results  from  failure 
of  union  of  the  naso-frontal 
and  maxillary  processes.    If 
this  failure  of  union  extends 
to  the  lateral  nasal  process, 
the  cleft   will   then   involve  the    alveolus   and 
open  into  the  nostril — a  condition  known  as  an 
alveolar  or  complete  hare-lip  and  usually  asso- 
ciated with  a  cleft  palate. 


■'"!/. 


Fio.  7. — Transverse  section  of  a  sheep-embryo  between  the  second  and  third 
weeks  (after  Bonnet). 
Medullary  or  primitive  groove ;  m.  Mesoderm ;  h.  Entoderm ;  pm. 
Parietal  mesoderm ;  vm.  Visceral  mesoderm ;  pe.  Primitive  endocardium  ; 
hp.  Heart  plates ;  ppc,  Pleuro-pericardial  cavity ;  pp.  Pericardial 
plates ;  c,  C'oelom ;  am.  Amnion.  The  Notochord  is  formed  from  tlie 
entoderm  in  the  region  of  the  medullary  groove. 

Coalescence  of  the  palatine  portions  of  the  naso- 
frontal, lateral  nasal,  and  maxillary  processes 
commences  at  the  anterior  palatine  foramen  and 
extends  both  forwards  and  backwards  from  this 


point,  the  lip  and  tlie  uvnla  being  the  last  parts 
to  unite ;  so  that  a  cleft  lip  or  cleft  uvula  may 
exist  without  the  involvement  of  the  jaw, 
whereas  the  reverse  condition  would  be  im- 
possible for  developmental  reasons. 

Failure  of  union  of  the  naso-frontal  and  lateral 
nasal  processes  medially  \\ith  the  maxillary 
process  laterally  gives  rise  to  what  is  known  as 
an  oblique  facial  cleft  (naso-orbital).  This  cleft 
commences  below  at  the  usual  situation  of  a 
hare-lip,  but  extends  upwards  around  the  base 
of  the  nose  to  the  iimer  canthus  of  the  eye,  and 


frontal  process,  and  the  same  condition  of  the 
lower  lip  from  non-union  of  the  mandil)ular 
proces.ses  (see  Fig.  11,  II). 

The  lower  jaw  results  from  a  metamorphosis 
of  the  mandibular  processes,  which  fuse  in  the 
middle  line  at  about  the  thirty-fifth  day.  At 
this  period  the  oral  margin  of  (lie  jaw  ])rescnts 
two  parallel  ridges,  the  outer  and  larger  ridge 


Fig.  8. — Showing  tlio  stomatodaeum  and  primltivo 
pliaryiix  of  a  third  week  embryo  in  sagittal  section 
(after  His). 

FB,  Fore-brain  ;  NF,  Naso-frontal  process  ;  MX.  Maxil- 
lary process ;  MD,  Jlandibiilar  process  ;  H,  Heart ; 
A,  Aorta;  1,  2,  3,  4,  Upper  four  visceral  arches; 
VC,  Visceral  clefts  (second  and  third) ;  P.  Pharynx  ; 
S,  Stomatodaeum;  OP,  Oral  plate;  DS,  Dorsum 
sellae  ;  0,  Oesophagus ;  L,  Lung  bud ;  PB-,  Buccal 
portion  of  hypophysis  cerebri ;  SP,  Sessel's  pouch. 

wiU  involve  the  soft  tissues  alone,  or  in  addition 
the  bone,  according  to  the  extent  of  non-union. 
Deficient  or  excessive  union  between  the  maxil- 
lary and  mandibidar  processes  produces  the 
conditions  known  as  macro-  and  micro-stoma 
respectively.  A  median  cleft  of  the  upper  or 
lower  lip  may  occur,  and  may  or  may  not 
involve  the  subjacent  bone  according  to  the 
extent  of  non-union.  Clefts  of  the  upper  or 
lower  lip  in  the  median  line  are  rare  deformities, 
more  especially  the  latter.  A  median  cleft  of 
the  upper  lip  would  arise  through  non-union 
of  the  globular  or  lateral  tubercles  on  the  naso- 


cu 


Fig.  9. — -Vertical  section  through  the  head  of  a  rat 
embryo  (from  Cunningham).  Ectoderm  is  repre- 
sented in  black,  mesoderm  stippled,  and  entoderm 
striated. 

T,  Tongue ;  H,  Heart ;  N,  Nasal  Cavity ;  CH,  Cerebral 
hemisphere ;  TH,  Thalamenccphalon ;  P,  Pineal 
body;  MB,  Mid-brain;  HB,  Hind-brain;  PBS 
Cerebral  part  of  hypophysis  cerebri;  PB'-,  Buccal 
part  of  hypophysis  cerebri;  AT,  Atlas;  EP,  Epi- 
stropheus; SG,  Spinal  ganglion;  BCA,  Basi-cranial 
axis;  FG,  Fore-gut;  A,  Amnion;  BP,  Bucco- 
pharyngeal membrane;  NF,  Naso-frontal  process; 
MD,  Mandibular  process;  S,  Stomatodaeum. 


developing  into  the  future  lip,  while  tlie  inner 
and  smaller  forms  the  gum  (see  Fig.  13). 
Incomplete  separation  of  the  oral  margin  of  the 
primitive  jaw  to  form  the  lips  and  gums  gives 
rise  to  the  condition  known  as  atresia  of  the 
lips  and  gums,  a  rare  malformation  except  in 
its  slight  forms,  in  which  it  occurs  in  association 
with  a  complete  hare-lip.  A  thick  fraenum 
labii  is  a  less  marked  degree  of  this  condition. 
The  mandible  at  an  early  period  consists 
entirely  of  Meckel's  cartilage,  embedded  in 
embryonic  tissue;  at  an  earher  .stage  it  con- 
sisted of  mesoderm  enclosed  between  the  snrface 
ectoderm  and  the  entoderm  of  the  fore-gut.  the 
entire  structure  being  known  as  a  visceral  arch 
(see  Fig.  1(5).  Growing  into  each  of  the  five 
visceral    arches    is    an    artery    (visceral    arch 


6 


vessel)  arising  from  the  truncus  arteriosus  of 
the  primitive  heart  (see  Fig.  10).  The  visceral 
arch  vessel  supplying  the  first  and  second 
arches  is  derived  from  the  external  carotid 
artery.  The  nerve  of  supply  to  the  first  visceral 
arch  {i.  e.  the  mandibular  nerve)  is  derived  from 
the  first  cephalic  ganghon,a  segment  of  the  neural 


Fig.  10. — Hiiman  embryo  of  about  three  weeks, 
showing  the  visceral  arclies  and  clefts  (after  Quain). 

S,  StomatodEieum ;  O,  Olfactory  depression ;  CV, 
Cerebral  vesicles ;  H,  Heart ;  TA,  Truncus  arteri- 
osus ;  A^,  Aortic  branch  of  first  visceral  arch ; 
VC,  Visceral  cleft  (first) ;  OV,  Otic  vesicle ;  JV, 
Jugular  vein ;  CV,  Cardinal  vein ;  DC,  Duct  of 
Cuvier ;  W,  Vitelline  vein  ;  UV,  tj mbUical  vein ; 
UA,  Umbilical  artery;  All,  Allantois;  P,  Placenta; 
PS,  Primitive  mesodermal  somite ;  nf,  Naso-frontal 
process ;  »i.  Maxillary  process ;  md,  Mandibular 
process. 

crest  or  ectodermic  tliickening  of  the  medullary 
groove,  the  earliest  representative  of  a  central 
nervous  system  in  the  embryo  (see  Figs.  6,  7). 

The  mcsodermic  tissue  of  the  visceral  arches 
becomes  differentiated  into  connective  tissue, 
and  this  constitutes  the  membranous  stage  of  the 
Jaw,  the  remaining  mesoderroic  tissue  forming 


the  muscular  and  connective  tissues  around  the 
jaw  (see  Fig.  17).  Cartilage  develops  in  each 
of  the  visceral  arches ;  the  cartilaginous  bar  of 


MX 


Fig.  11. — I.  Lateral  aspect  of  the  head  of  a  human 
embryo  about  a  month  old,  showing  the  olfactory 
pit  and  the  visceral  arches  and  clefts  (from  His). 
Olfactory  pit;  E,  Eye;  MX,  Maxillary  process; 
MX),  Mandibular  process ;  H,  Hyoid  arch ;  OV, 
Otic  vesicle ;  P,  Prosencephalon ;  T,  Thalamen- 
cephalon ;  M,  Mesencephalon. 


OP, 


II.  Front  aspect  of  the  head  of  hiunan  embryo 
about  five  weeks  old,  showing  the  globular  pro- 
cesses arising  from  the  naso-frontal  process,  the 
olfactory  pit  between  the  naso-frontal  (globular 
process)  and  lateral  nasal  process,  the  naso-lacrimal 
sulcus  between  the  lateral  nasal  and  maxil- 
lary process.  The  approximation  of  the  naso- 
frontal, lateral  nasal  and  maxillary  processes  is 
indicated  and  the  lateral  nasal  process  failing  to 
share  in  the  formation  of  the  free  margin  of  the  lip. 
(from  His). 

NF,  Naso-frontal  process ;  G,  Globular  process ;  LN, 
Lateral  nasal  process ;  MX,  Maxillary  process ; 
MD,  Mandibular  process ;  HA,  Hyoid  arch ;  H, 
Heart ;  E,  Eye ;  P,  Prosencephalon  or  fore-brain ; 
OP,  Olfactory  pit. 

the  first  visceral  arch  (mandibular)  being  known 

as  Meckel's  cartilage,  and  that  of  the  second 

visceral  arch  (stylo-hyoid)  as  Reichert's  cartilage. 

The  second  visceral  arch  is  represented  by  the 


stapes,  stylo-hyoid  process,  stylo-hyoid  ligament, 
and  the  lesser  cornua  of  the  liyoid  bone.     The 

third  arch  (thyreo- 
hyoid)  is  represented 
by  the  body  of  the 
hyoid  bone  and  its 
greater  cornua.  The 
fourth  and  fifth 
arches  fuse,  and  to- 
gether form  a  por- 
tion of  the  larynx 
(see  Fig.  18).  The 
intermediate  tissues 
of  the  neck  are 
formed  from  meso- 
dermic  tissue  invad- 
ing between  the  vis- 
ceral arches. 

The     tongue      de- 
FiG.  12.— Head  of  a  hunian    velops  from  the  walls 

embryo  about  two  months    of    the    pharynx,    its 

old,  showing  fusion  of  the  anterior  portion  from 
naso-frontal  process  (glo-   a     central     tubercle 

bular)  with  the  lateral 
nasal  and  maxillary  pro- 
cesses to  form  tlie  anterior 
nares  and  the  upper  hp 
(from  His). 

AN,  Anterior  nares ;  NF, 
Naso-frontal  process  (glo- 
bular) ;  MX,  Maxillary  pro- 
cess ;  MD,  Mandibular 
process. 


MX 


UD 


(tuberculum  impar) 
arising  between  the 
first  and  second  vis- 
ceral arches,  and 
from  two  lateral 
tubercles  arising  from 
the  ventral  extremi- 
ties of  the  mandibular 
arches ;  its  posterior 
portion  from  the  copula  or  united  ventral  ends 
of  the  hyoid  arches  (see  Pig.  16).    The  V-shaped 

AN' 


the  foramen  caecum  representing  the  apex  of 
their  junction.  The  buccal  portion  of  the  tongue 
contains  the  papillae  (including  the  vallate)  and 
is  concerned  vnth  mastication ;  the  pharyngeal 
portion  contains  glandular  and  lymph  tissue  and 
is  concerned  with  deglutition.  The  salivary 
glands  develop  as  ingrowths  from  the  oral  ecto- 
derm between  the  sixth  and  eighth  weeks. 


Fig.  14. — Diagram  showing  the  position  of  the  alveolar 

and  palatine  clefts  in  hare-lip  and  cleft  palate  (after 

Rose  and  Carless). 
»',  i-,  c,  m',  m'.  Deciduous  teeth ;    eg,  Endognathion  ; 

mg,    Mesognatliion    (represented    too    extensive) ; 

exg,  Exognathion.      The  centre  bone  behind   the 

endognathion  is  the  vomer. 

The  four  visceral,  or  branchial,  clefts  form 
deep  transverse  depressions  partly  encirchng 
the  front  part  of  the  fore-gut.  These  clefts 
probably  never  exist  as  pervious  channels  in 
man,  but  only  as  ectodermic  and  entodermic 
evaginations    from   the    surface   ectoderm  and 


pharyngeal 

EV 


entoderm 


MX 


LD 


respectively.  At  the 
bottom  of  these  clefts 
the  two  membranes  are 
in  contact  and  consti- 
tute what  is  known  as 
the  closing  membrane 
(see  Fig.  16).  In  the 
lower  vertebrates  the 
closing  membrane  dis- 
appears (see  Fig.  19), 
and  the  margins  of  the 
clefts  become  vascular- 
ized for  respiratory 
purposes  (gill  slits).  The 
visceral   clefts    (except 

Fig.  13. — I.     Head  of  liuman  embryo  about  two  and  a  half  months  old  (from  His),      the     first)     become    ob- 

The  labio-dental  groove  is  weU-formed  and  the  line  of  the  common  tooth-band  is  visible   literatcd     by    a    nieso- 

on  tlie  alveolar  prominence.     The  palatal  plates  of  the  naso-frontal,  lateral  nasal    (Jpj-jjjjc      invasion       be- 

and  maxillary  processes  are  commencing  to  grow  inwards  to  close  off  the  nasal  +1      I        ,.0     f  tUa 

from  the  buccal  cavity.  tween  tue  la>  ers  01  tue 

AN,  Anterior  Nares;    E,  Eye;    NF,  Nasofrontal  process;     MX,  Maxillary  process;    closing  membrane  (i.e. 

PP,  Palatal  process  or  palate ;    PD,  Hypophysial  depression.  ectoderm      and      entO- 

II.     Transverse  section  of  an  embryo  after  the  fusion  of  the  palatine  processes  with    derm).      This    invading 

each  other  and  with  the  nasal  septum  (ethrao-vomerine  plate)  to  close  off  the  nasal    mesoderm      is      merely 

from  the  oral  cavity.  ^     represented  in  the  first 

M,  Mouth ;    T,  Tongue ;   LD,  Labio-dental  sulcus ;  DG,  Dental  germ ;   MC,  Meckel's   YJggprf^I     cleft    bv    the 

cartilage;   J,  Jacobson's  organ ;   NC,  Nasal  cavity ;  EV,  Ethmo-vomrrine  plate.  V.         .  '  c  t.u 

^  '     '  b     •        >  J .        .  t-  connective  tissue  01  the 

line  of  union  of  the  two  main  portions  is  indi-    I    tympanum  (substantia  propria) ;  and  but  for  this 
cated  in  the  adult  organ  by  the  vallate  papillae,    1    connective  tissue  and  its  enclosing  membranes 


8 


the  cleft  would  be  pervious.  Should  this  meso- 
dermic  invasion  fail  to  take  place,  a  branchial 
fistula  results,  which  may  be  rendered  pervious 
if  the  closing  membrane  subsequently  ruirtures, 
or  be  blind  externally  or  internally,  accorcUng 
to  the  stage  of  niesodermic  development. 


Fig.  15.  —  Diagram  showing  the  relation  of  the 
teeth  to  tlie  oral  clefts.  The  left  side  of  the 
diagram  represents  the  normal  arrangement  of 
the  teeth  and  the  right  side,  a  condition  frequently 
present  in  complete  hare-lip. 

nf,  Naso-frontal  process;  In,  Lateral  nasal  process; 
mx.  Maxillary  process;  md.  Mandibular  process; 
1^,  1-,  C,  P',  V',  M',  M^,  M^,  the  Permanent  teeth ; 
S,' Supernumerary  tooth.  Note  absence  of  lateral 
incisor  on  right  side  of  diagram. 

The  visceral  clefts  are  botnided  above  and 
below  by  the  rounded  bars  of  tissue  known  as 
the  vnsceral  arches  (Fig.  16). 

The  first  visceral  or  branchial  cleft  normally 


EP      L 

Fig.  16. — Showing  the  front  wall  or  floor  of  pharynx 
in  a  human  embryo  at  the  fourth  week  {after  Hist. ) 

1,  2,  3,  4,  5,  The  five  visceral  arches ;  MD,  Mandibular 
or  first  arch ;  HA,  Hyoid  or  second  arch ;  T, 
Region  of  trimk;  CM,  Cleft  membrane  (first); 
E,  Ectoderm;  H,  Entoderm;  TI,  Tubercuhuii 
impar,  which  forms  part  of  the  anterior  portion  of 
tongue ;  LT,  Lateral  tubercles ;  FC,  Foramen 
caecvun ;  PT,  Posterior  or  pharyngeal  portion  >  f 
tongue  (copula);  EP,  Epiglottis;  L,  Larynx;  SP, 
Sinus  praecervicalis  (formed  by  a  sinking  in  of 
the  lower  arches  and  clefts  and  the  more  rapid 
growth  of  the  second  arch),  the  sinus  or  fossa  is 
subsequently  obliterated  by  the  coalescence  of  its 
margins  (HA  and  T). 

persists,  and  is  represented  by  the  external  ear, 
the  middle  ear,  and  the  auditory  tube ;  the  ex- 
ternal ear  representing  tlie  ectodermic  evagina- 
tion  of  this  cleft,  and  the  auditory  tube  and 
the  middle  ear  representing  the  entodermic 
evagination.     This  explains  why  the  external 


ear  (ectodermic  development)  is  lined  by  skin, 
and  the  auditory  tube  and  middle  ear  (ento- 
dermic development)  by  mucous  membrane. 

The  remaining  visceral  clefts  disappear,  except 
small  portions  of  their  imier  parts,  which  form 
respectively  the  fossa  of  Rosenmiiller  (a  recess 


Fig.  17. — Schematic  section  of  a  visceral  arch  (after 
Keith). 

CM,  Cleft  membrane;  E,  Ectoderm;  H,  Entoderm; 
N,  A,  V,  Nervous,  arterial,  and  venous  supply  of  a 
visceral  arch ;  M,  Muscle ;  C,  Cartilage.  The 
remainder  of  the  mesoderm  develops  into  the 
connective  tissues. 

behind  the  auditory  tube),  the  piriform  fossa, 
and  rudiments  of  the  thymus  and  thyreoid 
glands. 

During    the    fourth    week    the    membranous 
cranium  undergoes  a  cartilaginous  stage,  \\hich 


1, 


Fig.  18. — Showing  the  destination  of  the  cartilaginous 
visceral  arches  (after  Keith). 
2,  3,  4,  5,  The  five  visceral  arches;  MC,  Meckel's 
Cartilage;  M,  Malleus;  In.,  Incus;  S,  Stapes 
(tympano-hyal);  SP,  Stylo-hyoid  process  (stylo- 
hyal) ;  SHL,  Stylo-hyoid  ligament  (epi-hyal) ; 
LCH,  Lesser  cornu  of  hyoid  bone  (cerato-hyalj ;  B, 
and  GCH,  Body  and  greater  cornu  of  hyoid  Ijone 
(thyreo-hyal) ;  Th.,  Thyreoid  cartilage  formed  by 
the  fourth  and  fifth  arches;  T,  Tongue;  TR,  Tym- 
panic ring. 

is  imperfect  in  the  head  of  the  skeleton  of  man 
and  the  higher  vertebrates.  Cartilaginous  cover- 
ings are  provided  for  the  organs  of  smell,  sight, 
and  hearing  (see  Fig.  20),  and  a  cartilaginous 
visceral  skeleton  delineates  the   mandible,  the 


bones  of  the  middle  ear,  the  styloid  process, 
and  the  hyoid  bone  (see  Figs.  21,  22).  An 
imperfect  cartilaginous  capside  is  formed  around 
the  base  of  the  brain,  but  the  vault  remains 
membranous  (see  Fig.  23). 


The  cartilages  of  the  nose  are  derived  from 
the  septal  and  ethmoidal  cartilages,  themselves 
derivatives  of  the  trabeculae  cranii  (see  Fig.  20). 
The  pterygo -palatine  cartilage,  which  forms 
the  primitive  support  of  the  maxillary  process. 


A, 


AAO 
Fig.   19. — Showing  tlie  position  of  the  lieart  and  tlie 
relation   of   tlie   aortic   arclies   to   the   visceral   or 
gill-clefts  in  a  tish  (after  Gegenbaur). 
Auricle ;     V,    Ventricle ;     BA,    Bulbus    arteriosus ; 
VA,  Ventral  aorta ;   DA,  Dorsal  aorta ;    C,  Carotid 
artery;    AA^,  Artery  of  first  or  mandibular  arch; 
AA=^,  Artery  of  fifth  arch;    AA«,  Artery  of  sixth 
arch;    GC,  Gill-cleft;    E,  Eye;    NP,  Nasal  pit. 
The  sixth  arch  shown  hi  the  diagram  does  not  become 
differentiated  from  the  body  wall. 
I 


SHL 


GH 


Fig.   20. — Showing  the  cartilaginous  eranivun  at  an  early  stage  of 

development  (after  Wiedersheim). 
Diagram    I. — N,    Notochord ;      P.cti,    Parachordal    cartilages;     Tr., 

Trabeculae  cranii;  p,  Hypothysis  cerebri;  0,V,  A,  Situations  of 

olfactory,  visual,  and  auditory  organs. 
Diagram  II  (a  few-  days  later). — b.  Basilar  cartilage ;  na.  Nasal  septum  ; 

Eth,  Ethmoidal  cartilage  surrounding  (O)  olfactory  organ;   o.n.. 

Foramina  for  olfactory  nerve  fibres. 
The  commencement  of  formation  of  the  lens  by  a  dipping  in  of  the 

ectoderm  is  showii  and  the  cupping  of  the  optic  stalk  (retina)  to 

receive  this  invagination. 
1* 


Fig.  21. — Head  and  neck  of  a  luunan  foetus  four  and  a 
half  months  old  showing  the  visceral  skeleton 
exposed  (after  KSlliker). 

Md,  Mandible;  MG,  Meckel's  Cartilage;  M,  Malleus; 
I,  Incus;  S,  Stapes;  TR,  Tympanic  ring;  SP, 
Styloid  process;  SGM,  Stylo -glossus  muscle; 
SHL,  Stylo-hyoid  ligament;  LH,  Lesser  comu  of 
hyoid  bone ;  GH,  CJreater  cornu  of  hyoid  bone ;  MH, 
Mylo-hyoid  muscle;   SMM,  Stemo-mastoid  muscle. 

extends  to  the  proximal  end  of 
Meckel's  cartilage;  at  this  situation 
it  undergoes  ossification  in  birds  and 
reptiles,  forming  the  quadrate  bone. 
The  destination  of  the  quadrate 
bone  in  mammals  is  uncertain ; 
Gadow  believes  that  it  becomes  the 
tympanic  ring  (see  Fig.  22). 

Chondrification  commences  in  the 
visceral  arches  during  the  fourth 
week  and  is  visible  up  to  the 
seventh  month ;  at  this  period 
Meckers  cartilage  disappears,  ex- 
cept its  distal  extremity  \\'hich 
ossifies  and  forms  a  small  portion 
of  tlie  mandible  near  the  symphysis. 
Small  pendulous  tags  of  skin  con- 
taining a  nodule  of  cartilage  are  not 
infrequently  seen  below  and  in  front 
of  the  ear;  these  represent  small 
portions  of  persisting  cartilage  from 
the  first  visceral  arcii,  and  are  known 
as  accessor^'  auricles.  Similar  tags 
may  occur  in  the  neck  associated 
witli  the  branchial  clefts  and  are 
then  known  as  cervical  auricles. 


10 


The  proximal  extremity  of  Meckel's  cartilage 
persists  as  the  malleus  and,  possibly,  the  incus ; 
there  is,  however,  some  doubt  as  to  whether  the 


SHP 


Fig.  22. — Sho%viiig  the  parts  formed  from  tlie  cartilages 
of  the  maxillary  and  mandibular  processes  in  the 
human  skull  (after  Keith). 

mx,  Maxilla;  md,  Mandible;  MC,  Meckel's  Cartilage; 
C,  Condyle  of  jaw;  SML,  Spheno-mandibular 
ligament ;  AO,  Auditory  ossicles ;  TR,  Tympanic 
ring  (?  quadrate  bone) :  SHP,  Stylo-hyoid  process  ; 
P,  Palate ;   IP,  Internal  pterygoid. 

incus  may  not  belong  to  the  second  arch  or  to 
both  arclies  (see  Figs.  21,  22).  The  spheno- 
mandibular  ligament  of  the  mandible  probably 

AF 


(23).  Portions  of  the  condyle,  coronoid  process, 
and  symphysis  of  the  mandible,  are  formed  from 
cartilage,  but  are  ossified  from  the  surrounding 

LL 


DL 


EBD 


MD 


Flo.  23. — The  cranium  at  birth,  showmg  the  bones  that 
are  formed  in  membrane  and  those  formed  in 
cartilage  (stippled). 

F,  Frontal ;  P,  Parietal ;  O,  Occipital  (showing  inter- 
parietal portion  formed  in  membrane) ;  T, 
Temporal  (petro-mastoid  portion  formed  in 
cartilage) ;  TR,  Tympanic  ring ;  S,  Sphenoid ; 
MD,  Mandible  (symphysis  developed  in  cartilage) ; 
AF,  Anterior  fontanelle ;  PF,  Posterior  fontanelle ; 
W,  Wormian  bone  developed  in  membrane  in 
region  of  a-sterion  ;  there  is  a  similar  ossific  develop- 
ment shown  in  the  pterion  region  (epipteric  bone). 

represents  the  fibrous  sheath  of  the  intermediate 
portion  of  Meckel's  cartilage,  and  the  inter- 
articular  meniscus  of  the  mandibular  joint  is 
believed  to  be  also  a  remnant  of  this  structure 


Fig.  24. — Section  through  the  lip  and  mandible  of 
a  third  month  foetus,  showing  the  downgrowth 
of  oral  epitheliiun  to  form  the  dental  lamina 
(diagrammatic). 

LL,  Lower  lip  ;  LD,  Labio-dental  groove ;  T,  Tongue  ; 
E,  Ectoderm ;  BP,  Position  of  bucco-pharyngeal 
membrane  ;  DL,  Dental  lamina ;  EBD,  Enamel- 
bud  of  a  deciduous  tooth ;  EBP,  Enamel-bud  of 
a  permanent  tooth ;  EC,  Enamel-cells ;  DP, 
Dental  papilla ;  DS,  Dental  sac ;  B,  Bone  of 
jaw;  MC,  Meckel's  cartilage. 

membrane  bone.    Thus  the  mandible  develops 
eliiefly  from  intra-membranous  ossification. 

The  maxillary  process  continues  as  a  mem- 
branous structure  ^  until  the  seventh  or  eighth 
week,  when  ossification  commences  from  an 
uncertain  number  of  centres.  The  pre-maxil- 
lary  segments  result  from  an  ossification  in 
membrane  of  jDart  of  the  naso-frontal  and 
lateral  nasal  processes,  the  remaining  portion 
of  these  processes  entering  into  the  formation  of 
the  upper  lip  and  nose,  as  previously  mentioned. 
This  brief  outline  of  the  development  of  the 
visceral  arches  extends  to  the  period  at  which 
the  first  indication  of  tooth  formation  appears. 
The  origin  and  development  of  the  visceral 
arches  is  so  much  involved  in  the  morphology 
of  the  body  as  a  whole  that  there  is  some  difficulty 
in  abstracting  those  portions  oidy  which  liave  a 
direct  bearing  on  the  development  of  the  jaws. 
Tlie  reader  is  referred  to  Keith's  Human 
Embryology  and  Morphology,  or  the  section  on 

'  A  cartilaginous  bar  (the  palato-pterygoid)  is 
present  in  the  maxillary  process  of  some  of  the  lower 
animals. 


11 


cmbryoloiiv     in     Cumiingham's     Text-book     of 
Anatomi/.   ior  more  general  information. 

2.  Development  of  the  Teeth. — During  the  sixth 
week  of  intra -uterine  life  an  ingro\\  th  of  ectoderm 
into  the  substance  of  the  first  visceral  arch 
takes  place  in  a  situation  corresponding  to  the 
futiu'e  alveolar  border  of  the  ja«'  (see  Fig.  24). 
This  ectodermic  ingrowth  {tooth-band  or  zahn- 
leiste)  forms  a  continuous  lamina  and  becomes 
specialized  in  certain  parts,  where  teeth  are  to 
be  formed ;  and  in  these  positions  the  lamina 

LL 


REG 


MV 


Fig.  25. — Section  through  tho  lip  and  mandible  of  a 
six  months  foetus,  to  show  the  stage  of  tooth 
development  in  the  incisor  region.  (Diagram- 
matic.) 

LL,  Lower  lip ;  A,  Alveolar  ridge ;  LD,  Labio-dental 
groove;  E,  Ectoderm;  T,  Tongue;  DL,  Dental 
lamina ;  DS,  Dental  sac  (showing  its  two  layers) 
enclosing  the  deciduous  tooth-germ ;  EEC, 
External  enamel-celLs ;  REO,  Reticuliun  of  enamel- 
organ  ;  lEC,  Internal  enamel-celLs  (araeloblasts) ; 
E,  Enamel;  D,  Dentine;  O,  Odontoblasts; 
DP,  Dental  papilla ;  B,  Bone  of  jaw ;  ME,  Muscle 
fibres ;  MN,  Mandibular  nerve ;  MA,  Mandibular 
artery ;  MV,  Mandibular  veins  (venae  comites) ; 
MC,  Meckel's  cartilage. 

thickens,  so  as  to  appear  on  section  club-shaped, 
and  later  flask-shaped,  the  neck  of  the  "  flask  " 
retaining  its  comiection  with  the  epithelial 
lamina.  This  ectodermic  thickening  in  the  region 
of  tooth  formation  is  known  as  the  enamel- 
organ,  and  is  invariably  formed  on  the  outer  or 
labial  aspect  of  the  tooth-band.  Persistence  j 
of  portions  of  this  ectodermic  lamina,  either  in 
the  region  of  tooth  formation  or  elsewhere,  is 
believai  to  be  the  origin  of  multUocular  cystic 


epithelial  tumours,  dental  and  dentigerous  cysts, 
and  possibly  in  some  cases  of  epitheliomata. 

About  the  same  period,  or  a  week  or  two  later, 
the  mesodermie  tissue  m  the  neighbourhood  of 
the  enamel-organ  rises  up  in  a  papilla-like  form 
and  invagmates  the  enamel-organ,  so  that  the 
latter  a.ssumes  the  shape  of  a  bell.  This  special- 
ization of  the  mesoderm,  known  as  the  dental 
papilla,  takes  the  shape  of  the  tooth  it  represents. 
The  base  or  periphery  of  the  dental  papilla 
expands  and  encircles  the  tooth-germ,  giving 
rise  to   its   follicle  (see  Fig.  25).     Tomes  (32), 


APF 


PM  X 


MUMX 


PPF 


Fig.  26. — Showing  the  hard  palate  at  about  the  ago 
of  six  (modified  from  Keith). 

i',  i',  c,  m^,  in'-.  The  deciduoiui  teeth  ;  E,  Endognathion  ; 
M,  Mesognathion ;  PMX,  Palatine  process  of 
maxilla;  PP,  Palatine  process  of  palate;  APF, 
Anterior  palatine  fossa  (line  indicates  position  of 
foramina  of  Stenson) ;  SF,  Foramina  of  Scarpa 
lying  in  median  suture ;  PPF,  Posterior  palatine 
foramen ;  OF,  Gubeniacular  foramen  (showing  a 
lateral  incisor  in  its  crypt) ;  M'MX,  Crypt  for  first 
permanent  molar. 

however,  believes  that  the  portion  of  mesoderm 
forming  the  tooth-follicle  ma}'  be  a  spontaneous 
specialization  of  cells,  and  not  an  extension  from 
the  mesoderm  forming  the  dental  papilla. 

An  aperture  exists  in  the  bone  covering  the 
foUicle  for  the  passage  of  the  giibeniaculum,  a 
fibrous  structure  comiecting  the  tooth-sac  with 
the  overlying  gum  tissue  and  at  one  time 
believed  to  play  an  important  part  in  the 
eruption  of  the  teeth.  The  foramina  seen  in 
the  dried  skull  behind  the  upper  deciduous 
incisor  teeth  are  supposed  to  rej)resent  the 
persistence  of  these  apertures  after  ossification 
has  set  in  (see  Fig.  26). 

Successional  teeth  are  formed  about  the 
fifth  month  of  intra-uterine  life;  the  enamel- 
organ  from  specialization  of  cells  arising  from 
the  continued  growth  of  tiie  free  end  of  the 
tooth-band,  and  the  dentine  papilla,  as  before, 
from  the  mesoderm  in  the  neighbourhood  of 
the  enamel-organ.  An  exception  occurs  in  the 
case  of  the  permanent  molars,  all  of  which  arise 


12 


from  a  continuation  of  the  same  tooth -band  as 
that  which  gave  rise  to  the  second  deciduous 
molar ;  the  lateral  end  of  this  tooth -band  grows 
more  deeply  into  the  mesoderm  of  the  ja\\%  thus 
losing  its  continuity  with  the  surface  ectoderm. 
The  origin  of  supernumerary  teeth  can  be 
explained  by  an  adventitious  formation  of  an 
enamel-organ  from  the  tooth-band;  and  the 
reason  for  their  more  common  appearance  in 
the  region  of  the  clefts  may  be  the  fact  that 
the  tissues  are  apt  to  be  disturbed  in  these 
regions,  and  foreign  epithelium  may  be  included, 
which  takes  on  an  aberrant  growth  (e.  g.  the 
mid-line  and  cleft  dermoids). 


;5f    yea~ 

6  morithh 

,      Birth... 

ythmth  {before  birth 

iti-mt\[bi>lore  birth 


year 

qIK  year 

I  i'^  year 

f^^vQar 

Fig.  27. — Showmg  the  amount  of  calcification  the  deciduous  and 
permanent  teeth  have  undergone  at  various  ages.  The  deciduous 
teeth  are  represented  in  the  upper  part  of  the  iUustration. 

Theories  as  to  the  development  of  the  per- 
manent teeth-germs  are — 

(1)  Tomes  (32)  beheves  that  the  permanent 
teeth  grow  from  the  tooth-band  near  the 
neck  of  the  enamel-organ  of  the  deciduous 
teeth. 

(2)  Baume  is  of  the  opinion  that  the  per- 
manent teeth  develop  from  the  remains  of 
the  primitive  inflection,  without  having  any 
direct  connection  with  the  deciduous  teeth- 
germs. 

(3)  Rose  takes  the  view  that  the  deciduous 
and  permanent  teeth-germs  originate  from 
a  common  tooth-band  (zahnleiste),  but  ari.se 
independently  of  one  another,  the  mesoderm 
invaginating  the  ectodermic  tooth-band  and 
so  receiving  its  cap  of  enamel. 

The  enamel,  or  adamant,  is  formed  from  the 
enamel-organ,  and  chiefly  from  that  part  of  it 
which  is  applied  to  the  dental  papilla  (internal 
enamel-cells),  deposition  taking  place  from  within 
outwards.  The  dentine,  or  ivory,  is  formed  from 
those  cells  which  line  the  periphery  of  the  papilla 
(odontoblasts),  but  probably  not  by  their  direct 
calcification,  deposition  proceeding  from  without 
inwards.  The  dental  sac,  or  follicle,  is  divisible 
into  two  layers;  by  calcification  of  its  inner  or 


looser  layer  the  cementum,  or  substantia  ossia,  is 
formed,  while  from  its  outer  layer,  together  with 
the  surrounding  mesoderm,  arises  the  periosteum 
of  the  tooth-socket  (periodontal  membrane). 

Calcification  («.  e.  of  enamel  and  dentine)  of 
the  deciduous  incisors  commences  about  the 
seventeenth  week  of  intra-uterine  life,  and  of 
the  deciduous  molars  a  few  days  later  (see 
Fig.  27).  Calcification  of  the  cementum  is 
comparable  to  membranous  ossification  of  bone  ; 
it  occurs  later  than  that  of  the  enamel  and 
dentine,  the  cementum  not  being  formed  until 
those  tissues  are  completed,  and  often  not  being 
itself  completed  for  a  year  or  more  after  the  tooth 
has  erupted.  At  birth,  calcification 
~-,  has    involved    the    crowns    of    the 

deciduous  incisors  and  the  cusps  of 
the  canines  and  molars. 

Models  showing  the  formation  of 
the  tooth-germ  and  the  relation 
of  its  ectodermic  and  mesodermic 
elements  can  be  prepared  by  em- 
ploying Born's  (26)  method,  which 
is  briefly  as  follows — 

Serial  sections  of  the  tissue  are 

cut  with  an  automatic  microtome, 

and    every    fifth    section    or   so    is 

photographed  and  magnified  to  the 

extent  required.     The  outline  of  the 

enlarged  photograph  is  transferred 

to   wa.x   sheets    bearing    a   defimte 

relation  in  thickness  to  that  of  the 

section,  and  the  object  carved  out. 

The  cut  out  wax  sheets  are  placed  serially  in 

position  and  fixed  together  by  melting  tlie  wax 

with  a  hot  spatula,  thus  producing  a  wax  model 

of  the  original  object  photographed.     The  model 

may  then  be  coloured,  so  that  the  different  parts 

are  clearly  shown. 

3.  Ossification  and  Growth  of  the  Jaws. — It  has 
already  been  briefly  explained  liow  the  jaws, 
first  consisting  of  mesoderm,  rapidly  pass  through 
a  membranous  and  a  cartilaginous  stage.  It 
has  also  been  mentioned  that  in  the  mandible 
the  cartilaginous  bar,  known  as  Meckel's  carti- 
lage, disappears,  except  its  anterior  end,  which 
undergoes  direct  ossification  to  form  part  of  the 
symphysis  of  the  jaw.  The  remaining  portion 
of  Meckel's  cartilage  is  absorbed  and  replaced 
by  membrane,  in  which  one  or  more  centres  of 
ossification  appear. 

The  pterygo-palatine  cartilaginous  bar  of  the 
maxillary  process  serves  merely  as  scaffolding 
around  which  the  ossific  centres  develop,  and 
it  is  entirely  absorbed. 

The  maxilla  develops  from  one  centre, 
appearing  m  the  region  of  the  canine  tooth- 
germ  during  the  second  month  of  intra-uterine 
life.  An  infra- vomerine  centre  is  described  by 
Ramband  and  Renault  between  the  incisive 
and  palatine  portions  of  the  maxilla.     Albrecht 


13 


<and  Warinski  (10)  describe  the  development  of 
the  pre-maxilla  from  two  centres,  and  this  is 
borne  out  Ijy  cases  of  cleft  palate,  where  the 


Fig.  28. — Skull  at  the  age  of  four  luonths  (intra-uterine). 
'Museum  of  the  Royal  College  of  Sun/eons  oj  England. ) 

fissure  usually  passes  between  the  central  and 
lateral  incisors,  i.  e.  between  the  endognathion 
and  me.sognathion  segments  of  that  bone.     Mall 


Fig.  29. — Skull  at  the  age  of  five  months  (intra- 
uterine). (Museum  of  the  Royal  College  oj  Surgeons 
oj  England.) 

describes  the  development  of  the  pre-maxilla 
from  one  centre  of  ossification.  The  truth 
probably  lies  between  these  two  assertions,  viz. 


Fig.  30. — Skull  at  the  age  of  six  months  (intra-uterine). 
{Museum  oj  the  Royal  College  oj  Surgeons  oj  England. ) 

that  there  are  undoubtedly  two  centres  in  some 
cases,  but  whether  this  is  constantly  so  is  open 
to  discussion. 

There  seems  to  be  no  justification  for  the  old 
view,    perpetuated    by    Bland-Sutton  (2),  that 


there  are  six  separate  centres  of  ossification 
homologous  with  the  elements  of  the  reptihan 
jaw;  and  tlie  more  recent  work  of  Fawcett  (12) 
and  Low  (24)  in  this  country,  and  of  Bardeleben 
and  others  in  Germany,  seems  to  have  shown 
conclusively  that  the  mandiljle  is  develo])ed  in 


Fig.  31. — Skull  at  the  age  of  seven  montiis  (intra 
uterine).  Museum  oj  the  Royal  College  oj  Surgeons 
oj  England). 

membrane  as  a  single  element  at  the  sixth  week, 
but  that  the  ossa  mentalia  may  be  developed 
as  separate  bones  from  a  single  centre  of  ossi- 
fication in  the  region  of  the  sympliysis.  This 
research    has   been   founded   on    sections   and 


Fig.  32. — Skull  at  the  age  of  eight  months  (uitra- 
uterine).  (Museum  oj  the  Royal  College  oj  Surgeons 
oj  England.) 

1  cconstructions,  and  has  smce  been   confirmed 
by  J.  T.  Carter  (3). 

The  remains  of  Meckel's  cartilage,  or  rather 
its  morphological  representative,  can  be  traced 
in  the  malleus,  and  possibly  in  the  spheno-mandi- 
bular  ligament  of  the  jaw.     Fawcett  regards  this 


14 


ligament  as  an  independent  element,  from  the 
fact  that  it  is  well  developed  at  the  time  that 
Meckel's  cartilage  is  also  well  developed  and 
the  two  structures  can  be  separately  identified. 
The  adult  jaw  acquires  a  secondary  articulation 
in  the  mandibular  joint,  produced  by  the  de- 
velopment of  the  condyloid  jjrocess  from  the 
posterior  part  of  the  jaw,   and  thus  replacing 


Fig.  33. — Skull  at  birth,  showing  the  outer  alveolar 
plate  removed  to  expose  the  deciduous  teeth  in 
their  crypts.  (Odonlological  Museum,  Royal 
College  of  Surgeons  of  England.) 

the  primitive  articulation  between  the  mandi- 
bular and  the  palato-c[uadratum  of  the  lower 
vertebrates  (see  Fig.  22). 

Ossification  commences  near  the  mandibidar 
foramen  and  rapidly  extends,  so  that  by  the 
fourth  month  a  large  portion  of  the  mandible 
has  undergone  ossification,  and  the  maxilla  and 


Fig.  34.  Mandible  at  butli,  .showing  its  separate  halves 
united  by  fibrous  tissue  in  the  region  of  the  sym- 
physis (from  Tomes). 

pre-maxilla  are  almost  entirely  remodelled  in 
bone,  the  incisive  fissure  between  these  bones 
alone  persisting.  At  this  period  an  average  skull 
measures  one  and  a  half  inches  in  length,  an  inch 
in  breadth,  and  about  the  same  in  depth,  except 
that  posteriorlv  the  depth  is  rather  greater  (see 
Fig.  28). 

The  mandible  is  represented  by  two  frail 
troughs  of  bone  together  forming  a  horseshoe- 
shaped  arch,  the  extremities  of  which  are  opened 


out  and  everted.  The  coronoid  and  condyloid 
processes  are  distinguishable,  and  separated 
from  those  on  the  opposite  side  by  nearly  an 
inch.  The  crypts  for  the  various  deciduous 
teeth  are  indicated  by  indentations,  more 
pronounced  toward.s  the  front  of  the  bone. 
The  mylo-hyoid  groove  is  strongly  marked. 

The '  maxilla  consists  of  two  smooth  and 
slender  crescentic  bones,  and  exhibits  the 
partly  formed  crypts  for  the  deciduous  teeth. 
The  maxillae  form  the  greater  part  of  the 
hard   palate   and  enter  into   the   formation   of 


Fig.    35. — Maxilla   and   mandible   at  birth 

have  been  removed  from  the  jaws  on  one  side  to 
show  the  extent  to  which  they  are  calcified, 
(two-thirds  life  size). 

i',  i'-,  c,  »i',  nt~,  the  deciduous  teeth  removed  from  their 

respective  alveoli. 
A  bristle  (B)  is  shown  occupying  the  mandibular  canal 

(from  Tomes). 

the  oral,  nasal,  and  orbital  cavities.  The 
palate  is  smooth,  flat,  and  crescentic,  and 
limited  around  its  periphery  by  a  ridge  (alveolar) 
containing  the  crypts  of  the  deciduous  teeth 
The  anterior  palatine  foramen  is  situated  in  a 
relatively  forward  position  and  is  widely  open. 
The  entire  palate  falls  within  the  arch  formed 
by  the  mandible,  and  so  is  open  to  inspection 
from  the  under  surface  of  the  skull. 

In  the  fifth  month  the  pre-maxillae  and 
maxillae  fuse,  but  for  many  years  after  birth 
the  incisive  fissure  can  be  traced  on  the  oral 
surface  in  the  dried  skull  (.see  Fig.  29).  The 
measurements  of  the  skull  have  increased  about 
half-an-inch,  and  the  condyles  are  separated  by 
a  full  inch.  Calcification  of  the  deciduous  teeth 
commences  about  this  period  (see  Fig.  27). 


15 


At  the  sixth  month  Meckel's  cartilage  begins 
to  degenerate.  The  skull  has  increased  in  size, 
more  especially  in  its  length,  which  now  measures 
three  inches  (see  Fig.  30). 

At  the  seventh  month  the  development  of 
the  parietal  tuberosities  gives  greater  breadth 
to  the  skull  (see  Fig.  31).  Traces  of  calcification 
can  be  detected  in  all  the  deciduous  teeth  (see 
Fig.  27). 

At  the  eighth  month  the  skull  has  increased 
as  a  whole  and  begins  to  assume  the  appearance 
that  it  has  at  birth  (see  Fig.  32). 

At  the  ninth  month,  or  birth,  an  average 
child  measures  twenty  inches  in  length,  and 
weighs  seven  pounds.  The  length,  breadth, 
and  depth  of  the  skull  are  respectively  4J", 
3",  and  3i",  and  the  condyles  are  2J"  apart 
(see  Fig.  33).  The  mandible  appears  as  a 
shallow  trough  of  bone  with  bulgings  corre- 
sponding to  the  situations  of  the  enclosed 
deciduous  teeth.  The  two  halves  of  the  man- 
dible are  united  at  the  symphysis  by  fibrous 
tissue,  bony  union  not  occurring  until  the  first 
or  second  year  after  birth  (see  Fig.  34).  The 
condyloid  process  is  rounded  and  nearly  on 
a  horizontal  level  with  the  alveolar  border ; 
the  entire  body  of  the  jaw  is  thin  and  trans- 
lucent in  parts ;  the  basal  element  hardly 
exists,  so  that  the  mandibular  foramen  is  nearly 
on  a  level  «ith  the  lower  margin  of  the 
jaw.  The  orifice  of  the  mandibular  foramen 
is  below  and  behind  the  crypt  of  the  first 
permanent  molar.  The  crypt  for  this  tooth 
extends  into  the  ascending  ramus,  and  the 
antero-internal  cusjj  of  the  contained  tooth  has 
commenced  to  calcify.  The  coronoid,  condyloid, 
and  angular  processes  are  equidistant  from  one 
another.  The  condyloid  process  forms  an  obtuse 
angle  (175  °)  with  the  body  of  the  mandible. 

The  maxilla  at  birth  is  an  irregular  shaped 
bone,  and  the  main  mass,  known  as  its  body, 
supports  two  raised  tables  of  bone  forming 
portions  of  the  floor  of  the  nose  and  of  the 
orbit  (see  Fig.  35).  The  periphery  of  the  body 
of  the  maxilla  is  limited  by  a  raised  ridge 
(alveolar)  containing  the  unerupted  teeth.  Pro- 
jecting upwards,  outwards,  and  inwards  from 
the  body  of  the  bone  are  respectively  the  frontal, 
zygomatic,  and  palatine  processes. 

The  maxillary  sinus  at  birth  is  an  oval- 
shaped  cavity  half  an  inch  in  length,  and  situ- 
ated between  the  orbit  and  the  alveolar  portion 
of  the  jaw ;  previous  to  this  it  was  visible  in 
the  third  month  of  intra-uterine  life  as  a  recess 
formed  by  an  evagination  between  the  future 
middle  and  inferior  conchae.  Duplication  of 
this  primitive  recess  or  pouch  sometimes  occurs, 
which  possibly  accounts  for  the  duplication  of  the 
ostium  maxillare  of  the  adult  snius  (28),  i.  e. 
the  two  pouches  fuse  distally,  leaving  the  two 
points  of  evagination  as  the  adult  ostia.     Tlie 


infra-orbital  foramen  lies  open  in  the  floor  of 
the  orbit  directly  above  the  tooth-sockets. 
The  incisor  teeth  lie  directly  under  the  floor 
of  the  nose,  and  the  molars  under  tlie  floor  of 
the  orbit,  while  the  canine  teeth  are  inter- 
mediate in  position  and  situated  in  the  base  of 
the  nasal  process. 

At  birth,  the  greater  portion  of  the  crowns  of 
the  deciduous  incisors  are  calcified,  not  much 
more  than  the  cusps  of  the  canines,  and  only 
the  masticating  surfaces  of  the  molars  (see 
Figs.  27,  35).  Besides  the  deciduous  dentition, 
representatives  of  twenty-four  of  the  germs  of 
the  permanent  teeth  are  present,  and  those  of 
the  first  permanent  molar  have  commenced  to 
calcify.  Under  ordinary  conditions  calcification 
progresses  graduallj'  and  uniformlj',  and  towards 
the  end  of  the  seventh  month  the  earliest  teeth, 
generally  the  lower  incisors,  erupt,  and  dentition 
or  teething  is  said  to  have  commenced  (see 
Fig.  37). 

B.  DEVELOPMENT  OF  THE  JAWS  AND  TEETH 
AFTER  BIRTH 

I.  THE  FIRST  DENTITION 
1.  Eruption  of  the  Teeth. — Even  at  the  present 
day  the  cause  of  the  eruption  of  tlie  teeth  is 
not  clearly  understood,  and  the  theories  so  far 
advanced  do  not  satisfactorily  explain  its 
mechanism.  Possibly  several  factors  are  com- 
bined in  this  vital  process,  and  the  tendency  at 
present  has  been  to  advance  a  theory  depending 
solely  on  one  factor  for  explaining  the  \\'hole 
process. 

(a)  Tlieories  of  Eruption  of  the  Teeth. — The 
earliest  of  these  theories  accounted  for  the 
process  by  assuming  that  the  teeth  rise  up  from 
their  sockets  in  consequence  of  a  deposition  of 
lime  salts  at  the  ends  of  their  roots ;  or,  in  other 
words,  that  the  eniption  of  the  teeth  is  due  to 
their  elongation.  This  view  presupposes  that 
the  ends  of  their  roots  occupy  the  same  position 
throughout  eruption.  The  objections  to  such  a 
theory,  apart  from  this  assumption,  are  found 
in  the  following  facts  :  Teeth  with  stunted  or 
imperfectly  formed  roots  are  not  infrequently 
erupted,  whereas  teeth  having  well-formed  roots 
may  remain  embedded  in  the  jaw  during 
a  lifetime,  or  only  erupt  late  in  life  and 
without  any  additional  calcification  hav^ing 
taken  place  in  the  meanwhile.  A  further 
argument  against  this  view  is  the  disproportion 
between  the  distance  a  tooth  travels  in  the 
process  of  eruption  and  the  depth  of  the 
tissue  added  to  its  root  during  a  like  period. 
Tomes,  referring  to  comparative  anatomy,  re- 
marks :  "  The  tooth  of  a  crocodile  moves 
upwards,  tooth-pulp  and  all,  obviously  impelled 
by  something  different  from  mere  elongation ; 
and  my  ov\-n  researches  upon  the  development 


16 


and  succession  of  reptilian  teeth  clearly  show 
that  a  force  quite  independent  of  an  increase 
in  their  length  shifts  the  position  of  and 
'  erupts  '  successive  teetli." 

Another  view  attributes  the  process  to  a 
growth  of  bone  at  the  lower  portion  of  the  tooth 
socket.  There  is  no  evidence  in  favour  of  this 
view,  and  it  camiot  be  shown  that  there  is  a 
greater  development  of  bone  taking  place  during 
tooth  eruption  at  the  apex  of  a  socket  than  at 
other  parts  of  the  maxilla. 

A  third  view,  advanced  by  the  wTiter's  father 
(7),  regarded  the  eruption  of  the  teeth  as  due  to 
the  general  growth  and  advance  of  the  bone 
towards  the  surface,  carrying  with  it  the  con- 
tained teeth ;  and  likened  the  process  to  the 
shedding  of  the  epithelium.  The  exfoliation 
of  teeth,  roots,  and  sequestra  was  mentioned  in 
support  of  this  view,  and  the  term  "  bone- 
currents  "  introduced  to  explain  the  process. 
This  opinion  was  first  expressed  in  a  course  of 
lectures  delivered  at  St.  Bartholomew's  Hospital 
in  1867,  and  published  subsequently,  but 
certainly  not  until  an  almost  similar  view  had 
been  expressed  in  an  admirable  paper  in  the 
Vierteljahrsschrift,  by  Robert  Baume  (1). 

Thornton  Carter  believes  that  the  cause  of 
eruption  is  to  be  found  in  the  disproportionate 
growth  occurring  in  the  tissues  forming  the  tooth 
and  the  tissues  surrounding  the  tooth.  He 
states  his  case  as  follows — 

"  The  principal  factor  in  the  eruption  of  the 
teeth  is  to  be  found  in  disproportionate  growth 
of  the  various  tissues  in  the  immediate  vicinity 
of  the  forming  tooth.  For  any  organ  to  move 
there  must  be  growth,  and  for  there  to  be  growth 
there  must  be  rapid  cellular  proliferation. 
With  cessation  of  this  proliferation  the  tissue 
assumes  its  adult  histological  structure  and 
henceforth  is  little  adapted  for  change  of  form 
as  distinct  from  mere  increase  in  bulk. 

"  When  growth  is  slow  in  one  part  and  there 
is  rapid  growth  in  adjoining  tissues,  it  will  cause 
movement  in  the  more  rigid  tissue. 

"  In  the  case  of  a  tooth  there  is  at  first  rapid 
proliferation  of  cells  to  form  the  tooth  ;  in  the 
meantime  the  cells  forming  the  tooth-sac  have 
assumed  their  adult  structure,  and  the  tooth 
is  swung  up  in  a  sac  of  connective  tissue  con- 
tinuous with  the  deeper  fibres  of  the  oral  mucous 
membrane  by  means  of  the  so-called  '  guber- 
naculum  ' ;  this  gubernaculum  from  its  structure 
can  exercise  no  traction  in  itself,  it  is  merely 
sessile. 

"  At  this  period,  if  a  section  of  a  developing 
tooth  be  examined,  it  will  be  seen  that  the 
tooth  is  lying  in  a  bony  crypt  invested  by 
the  tooth-sac,  which  is  composed  of  fibrous  tissue 
poor  in  cellular  elements  except  where  in  con- 
tact with  the  tooth,  and  has  little  if  any  attach- 


ment to  the  sides  of  the  bony  crypt.  At  that 
point,  however,  where  the  gubernaculum  passes 
through  the  roof  of  the  crjrpt  to  blend  with  the 
fibres  of  the  mucous  membrane  it  also  has  a 
close  comiection  with  the  margin  of  the  bone. 
It  will  be  seen  that  the  bone  at  this  part  is 
growing  rapidly,  the  nuclear  changes  associated 
with  cell  division  being  remarkably  active. 
This  rapid  development  in  one  part,  taking  place 
under  tissues  which  from  their  poorness  in 
cellular  elements  are  no  longer  capable  of  rapid 
growth,  leads  to  a  change  of  position  and  gradual 
emergence  of  the  tooth  from  its  crypt  and 
'  onwards  until  it  reaches  its  functional  position." 

Warwick  James  (22)  has  recently  advanced 
the  view  that  the  epithelium  derived  from  the 
tooth-band  and  enamel -organ,  which  extends 
from  the  oral  surface  of  the  jaw  to  the  enamel- 
cap  of  the  developing  tooth,  may  be  the  guiding 
force  that  directs  the  tooth  to  the  point  at 
which  it  should  erupt.  This  view  is  supported 
by  the  fact  that  previous  to  eruption  the  tissues 
overlying  the  tooth  contain  large  quantities  of 
epithelium  arranged  in  cords  or  columns,  and 
i  Warwick  James  has  showii  by  means  of  serial 
I  transverse  sections  that  these  columns  are 
continuous  from  the  surface  epithelium  to  the 
cap  of  the  epithelium  overlying  the  crown  of  the 
erupting  tooth.  The  cells  of  these  epithelial 
;  columns  show  various  stages  of  rarefaction 
or  degeneration,  more  pronouncedly  in  the 
region  of  the  advancing  tooth,  and  apparently 
serve  the  purpose  of  lessening  the  resistance 
to  the  force  that  propels  the  tooth  into  its 
alignment. 

These  columns  or  coils,  on  reaching  the  surface 
of  the  jaw,  appear  to  open  out  in  association 
with  the  growth  of  the  surrounding  tissues,  and 
the  tooth  is  thus  brought  nearer  to  the  surface ; 
or,  should  they  become  distended  with  fluid 
before  reaching  the  surface,  may  be  the  origin 
of  the  small  cystic  swellings  occasionally  found 
over  erupting  teeth.  The  directing  force  of 
eruption,  both  of  the  deciduous  and  permanent 
teeth,  might  well  be  explained  by  the  presence 
of  these  columns  of  cells,  and  their  branchings 
would  likewise  account  for  a  tooth  taking  an 
aberrant  course  or  even  failing  to  erupt. 

The  degeneration  or  absorption  of  tissue, 
whether  of  ectodermic,  mesodermic,  or  ento- 
dermic  origin,  is  a  prominent  factor  in  the 
development  of  the  body  as  a  whole.  The 
formation  of  the  lip  furrow  is  an  example  of 
mesodermic  absorption ;  whereas  the  patency  of 
the  mouth  and  anus  is  brought  about  by  absorp- 
tion of  ectodermic  and  entodermic  structures, 
to  allow  the  oral  and  anal  pits  to  communicate 
with  the  fore-  and  hind-gut  respectively. 

The  action  of  the  liquor  foUiculi  in  direct- 
ing   the  ovum  towards    the   periphery  of  the 


17 


AM 


ovary  occurs  as  a  somewhat  parallel  instance 
of  what  may  be  accomplished  by  the  fluid  col- 
lecting in  front  of  an  erupting  tooth,  although 
in  neither  instance  is  it  an  explanation  of  the 
propelling  force.  Warwick  James  gives  as  an 
analogy  the  development  of  a  hair,  which  is 
preceded  in  its  eruption  Ijy  a  fatty  degeneration 
of  the  column  of  the  ectodermic  cells  filling  its 
follicle. 

The  writer  (8)  recently  had  a  case  that  some- 
what bears  out  Warwick  James's  theory  of 
eruption ;  the  subject  was  a  boy,  aged  about 
twelve  years,  who  had  a  dentigerous  cyst  of  the 
mandible  about  the  size  of  a  hen's  egg  in  con- 
nection with  his  second  permanent  molar ;  the 
latter  tooth  was  in  position  for  erupting,  and 
over  its  crown  there  was  a  small  bluish  tense 
cyst,  apparently  not  connected  with  the  deeper 
cyst  of  the  jaw,  but  representing  the  degenerated 
(cystic)  epithelium  over  the  erupting  tooth. 
Thus  the  changes  described  by  Warwick  James 
in  the  epithelium  over  the  erupting  tooth  had 
taken  place  to  an  excessive  degree,  but  had 
been  ineffectual  in  aiding  eruption  owing  to 
some  disturbance  in  the 
propelling  force  brought 
about  by  the  cystic  con- 
dition of  the  body  of 
the  jaw. 

(b)  Normal  Eruption 
of  the  Teeth.— Most  of 
the  mammalia  possess 
teeth,  and  these  organs 
assume  different  forms 
and  shapes  according  to 
the  purposes  for  which 
they  are  designed.  In 
some,  certain  teeth,  usu- 
ally those  towards  the 
front  of  the  mouth,  are 
developed  to  an  enorm- 
ous extent  for  the  ]5ur- 
pose  of  defence  and  as 
weapons  of  offence ;  in 
others  the  teeth  are 
sharp  and  chisel-edged 
for  cutting  or  biting 
through  the  hard  pro- 
tective coverings  of 
animal  and  vegetable 
fibre  ;  others  again  pos- 
sess broad  uneven  sur- 
faces for  crushing  or 
masticating  food,  pre- 
paratory to  its  being 
acted  upon  by  the  oral, 
gastric,  and  intestinal 
juices.  The  food  of 
man  requires  both  cutting  and  crushing,  and 
he  is  supplied  with  teeth  designed  to  serve  both 
these  purposes.     The  teeth  of  man  also  serve 


TR 


AM 


Fig.  36.— Thp  chief  tyyes 
of  the  mandibular  articu- 
lation (after  Keith). 

A,  Carnivorous ;  B,  Omni- 
vorous ;  C,  Herbivorous ; 
C,  Condyle;  IM,  Inter- 
articular  meniscus;  PG, 
Post-glenoid  spine;  AM, 
Acoustic  meatus ;  TR, 
Tympanic  ring ;  M,  Mas- 
toid ;    PM,  Paramastoid. 


as   adjuncts  in  vocalization   and   in   articulate 
speech. 

The  mandibular  joint  is  likewise  adapted  to  the 
functions  that  it  subserves  in  the  shape  and 
formation  of  its  articular  surfaces ;  thus,  in  the 
carnivora,  where  a  hinge  action  alone  is  required, 
the  condyles  are  long  in  their  transverse  dia- 
meters, and  set  in  deep  mandibular  fossae 
bounded  in  front  and  behind  by  strong  but- 
tresses ;  in  the  herbivora,  the  condyle  is  rounded, 
the  mandibular  fossa  shallow  and  extensive,  and 
the  ascending  ramus  of  the  jaw  long,  thus 
allowing  of  gUding  movement.  In  man  and  the 
omnivora,  the  articulation  combines  the  char- 
acters of  the  above  tjqjes ;  the  condyle  is  ovoid 
in  shape  with  its  long  diameter  nearly  transverse, 
and  the  mandibtilar  fossa  is  intermediate  in 
depth.  The  hinge  movement  in  the  joint  occurs 
between  the  inter-articular  meniscus  and  the 
condyle,  and  the  gliding  movement  between 
the  inter-articular  meniscus  and  the  skull  (see 
Fig.  36). 

Previous  to  the  eruption  of  the  first,  or 
deciduous,  teeth  the  outline  of  their  forms  can 
be  discerned  more  or  less  distinctly  beneath  the 
gums.  Soon  after  birth  a  slight  flat  elevation 
can  usually  be  felt,  and  sometimes  seen,  in  the 
incisor  region  on  the  outer  aspect  of  the  alveolus. 
Later  these  flat  elevations  appear  white  and  be- 
come more  firm,  until  the  mucous  membrane 
over  the  erupting  tooth  is  so  stretched  that  the 
crown  of  the  tooth  is  plainly  visible  througli  the 
transparent  structure.  The  sudden  subsidence 
of  the  mucous  membrane  after  its  penetration  by 
the  erupting  tooth  is  apt  to  give  the  impression 
that  eruj)tion  took  place  some  days  previously. 
The  deciduous  molars  produce  uneven  elevations 
on  the  surface  of  the  alveolus,  which  gradually 
assume  the  form  of  the  crown  of  the  erupting 
tooth.  The  mouth  of  the  infant  at  this  period 
is  moist,  owing  to  excessive  secretion  of  saliva, 
due  probably  to  the  physiological  irritation  of 
commencement  of  teething,  or  to  the  activity 
of  growth  that  is  taking  place  in  the  salivary 
glands  at  this  period  in  preparation  for  carbo- 
hydrate digestion. 

Man,  of  all  animals  the  most  dependent  upon 
his  own  species,  is  not,  as  a  rule,  furnished  with 
any  teeth  until  after  the  sixth  month  of  hi.s  exist  - 
ence,  and  the  process  has  seldom  terminated 
before  manhood  is  attained.  During  the  period 
between  birth  and  the  time  •when  he  possesses 
a  sufficient  number  of  teeth  to  render  him 
independent  of  his  mother,  he  is  supplied  witli 
a  food  containing  in  solution  or  cnuilsion  all 
the  constituents  necessary  for  nourishing  and 
developing  the  tissues. 

In  a  healthy  iirfant  a  lower  central  incisor 
usually  makes  its  appearance  about  the  end 
of  the  .seventh  month,  and  is  joined  by  its 
fellow  within  a  week  or  .so  later.     Then  follow 


18 


the  upper  central  and  lateral  incisors.  The 
lateral  incisors  of  the  mandible  are  next  in 
succession,  after  the  corresponding  teeth  of  the 
maxUla  have  been  erupted  some  two  months. 
The  lateral  incisors  of  both  jaws  erupt  behind 
the  plane  of  the  central  incisors  and  canines. 
About  the  twelfth  month  the  first  molars 
appear  at  some  little  distance  from  the  lateral 
incisors,  the  space  thus  formed  being  occupied 
some  six  months  later  by  the  canines,  the  next  in 
order  to  appear.  After  a  similar  interval  the 
second  molars,  the  last  teeth  of  the  decidu- 
ous dentition,  take  up  a  position  in  the  dental 
arch  posterior  to  the  first  molars,  thus  com- 
pleting at  about  the  age  of  two  years  the  first 
dentition,  which  is  said  (and  in  the  opinion  of 
the  writer  correctly)  to  commence  earlier  and 
terminate  sooner  in  girls  than  in  boys.  The 
teeth  are  thus  seen  to  erupt  to  some  extent  in 
groups,  with  intervals  of  two  to  four  months. 
The  dates  at  which  the  individual  teeth  erupt 
are  subject  to  a  variation  within  what  may  be 
termed  the  normal. 

The  following  table,  although  only  approxim- 
ately correct,  is  sufficiently  near  the  truth  to 
serve  all  practical  purposes,  and  is  easy  to 
memorize — 


Teeth. 

Date  of 
Eruption. 

DcKATiON  or 
Eruption. 

CentraIincisors|'°^'^''| 
I  upper  J 

Lateral  incisors  (;'PPp^;j 

First  molars 
Canines 
Second  molars 

8th  month. 

10th  month. 

12th  month. 
18th  month. 
24tli  month. 

1  to  2  weeks. 

1  to  2  months. 

1  to  2  months 

2  to  3  months. 

3  to  4  months. 

Frequently  the  upper  lateral  incisors  erupt 
simultaneously  with,  or  soon  after,  the  upper 
central  incisors ;  and  the  lower  lateral  incisors 
are  closely  followed  by  the  first  molars ;  so  that 
an  interval  results  between  the  eruption  of  these 
two  groups  of  teeth. 

(c)  Pathological  Eruption  of  the  Teeth. — The 
order  and  dates  of  eruption  of  the  deciduous 
teeth  in  the  process  of  teething  are  subject 
to  great  variation.  Besides  a  slight  variation 
according  to  sex  there  is  a  more  pronounced 
racial  and  geographical  variation.  Breast- 
fed children  cut  their  teeth  earlier  than 
those  that  are  bottle-fed.  Cautley  thinks  the 
explanation  of  this  may  be  that  the  salts  in 
the  human  milk  are  more  reachly  assimilated 
than  those  in  the  cooked  milk  of  other  animals. 
Premature  teething  (dentitio  praecox)  or  delayed 
teething  (dentitio  tarda)  may  be  a  family  trait. 
Still  (30,  p.  5)  refers  to  a  family  in  which  a  boy 
cut  a   ower  incisor  when  fourteen  days  old  and 


a  second  incisor  a  week  later ;  his  brother  was 
born  with  a  lower  incisor.  In  another  case  that 
he  mentions  one  girl  had  two  lower  incisors  erupt 
at  six  weeks  old,  and  her  sister  got  her  first  tooth 
at  the  age  of  four  months.  A  similar  hereditary 
di.sposition  to  early  eruption  came  under  the 
notice  of  the  writer  a  few  years  ago.  An 
infant  a  month  old  presented  a  fully  erupted 
lower  incisor;  at  birth  two  lower  incisors 
had  been  present,  but  one  of  these  had  been 
removed.  A  sister  of  this  child  was  also 
born  with  two  lower  incisor  teeth ;  and  the 
father  of  these  children  likewise  had  two  lower 
teeth  present  at  birth.  The  eight  remaining 
children  had  no  noticeable  derangement  in  their 
dates  of  eruption. 

An  early  commencement  of  teething  does  not 
necessarily  imply  an  early  completion ;  one  or 
more  teeth  may  be  erupted  at,  or  soon  after, 
birth,  while  the  remaining  teeth  follow  at  the 
usual  periods ;  or  the  first  teeth  may  be  cut  at 
the  usual  time  and  the  subsequent  ones  delayed. 
The  writer's  father  (7)  met  with  several  instances 
where  teeth  were  present  at  birth,  and  a  few 
cases  where  teething  was  delayed  until  after 
the  second  year.  Haller  (19),  in  his  Elements 
of  Physiology,  records  nineteen  instances  of 
infants  born  with  one  or  more  teeth  fully  erupted  ; 
and  Crump  quotes  the  case  of  a  child  who  had  a 
complete  dentition  at  birth. 

Teeth  present  at  birth  are  liable  to  interfere 
with  suckling,  to  injure  the  nipples,  or  cause 
ulceration  of  the  mucous  membrane  of  the 
mouth.  The  use  of  a  shield  wiU.  prevent  injury 
to  the  nipples,  but  should  the  teeth  be  loose 
or  badly  formed  they  should  be  removed. 

James  and  Pitts  (21)  record  a  case  in  which 
all  the  first  permanent  molars  were  erupted  at 
the  age  of  four,  and  a  year  later  the  four  central 
incisors  were  also  present.  They  mention 
sixteen  cases  in  which  the  first  molars  erupted 
before  the  age  of  five,  two  beuig  the  subjects 
of  marked  rickets. 

It  is  said  that  the  effect  of  rickets  is  to  delay  the 
eniption  of  the  teeth,  besides  causing  irregularity 
in  its  periods.  The  first  statement,  however,  in 
the  case  of  the  permanent  teeth,  is  not  borne  out 
by  the  researches  of  James  and  Pitts  (21).  The 
amount  of  derangement  will  depend  upon  the 
date  of  origin  of  the  disease.  According  to 
Still  syphilis  does  not  interfere  with  the  eruption 
of  the  teeth,  unless,  as  happens  so  frequently,  it 
is  associated  with  rickets.  Still  gives  no  support 
to  the  generally  accepted  view  that  syphilis 
conduces  to  premature  teething.  In  mentally 
deficient  children  the  teeth  are  often  late  in 
appearing  and  irregular  in  their  order  of  erup- 
tion. J.  G.  Turner  (37)  found  the  permanent 
teeth  late  in  appearing,  and  their  predecessors 
retained  beyond  their  normal  period,  in  certain 
cases  of  cretinism ;  and  Still  refers  to  a  case  of 


19 


Mongolian  imbecility  in  which  the  teeth  were 
both  late  in  appearing  and  irregular  in  their 
order  of  eruption.  He  found  the  same  defects 
in  a  microcephalic  idiot. 

H.  W.  Trewby  (35)  records  the  case  of  a  child, 
aged  twelve  years,  in  whom  all  the  deciduous 
molars  were  retained  except  the  fir.st  lower, 
which  had  been  replaced  by  their  successors. 
There  was  no  history  or  appearance  of  rickets, 
nor  any  other  apparent  cause  for  the  retarded 
eruption  of  the  permanent  teeth.  The  decidu- 
ous teeth  were  well  spaced,  and  on  subsequent 
extraction  their  roots  were  found  to  be  entirely 
absorbed.  A.  B.  Gibson  (15)  relates  an  instance 
in  which  none  of  the  permanent  teeth  and  only 
seven  of  the  deciduous  teeth  had  erupted  in  a 
woman  of  twenty-four  years.  Teething  com- 
menced at  the  age  of  eight  months,  but  an 
interval  of  t^^'o  years  followed  before  the  next 
tooth  in  succession  appeared.  Marshall  (25) 
refers  to  the  case  of  a  strong  powerful  man 
who  liad  no  teeth  up  to  the  age  of  seventeen ; 
four  teeth  then  erupted  in  the  lower  jaw,  but  no 
others  followed  ;  the  jaws  of  tliis  man  were  small 
and  undeveloped.  His  son's  dentition  com- 
prised only  four  lower  incisor  teeth.  Choquet 
(ti)  reports  a  case  in  which  a  lateral  incisor  tooth 
erupted  at  the  age  of  forty.  A.  \V.  W.  Baker 
records  the  case  of  a  man,  aged  eighty,  in  whose 
jaw  a  tooth  in  the  third  lower  molar  region 
presented  under  the  gum  ;  a  second  lower  pre- 
molar on  the  opposite  side  of  the  ]aw  had  erupted 
only  seven  years  previously.  Boxalli  and  Baumes 
have  each  reported  cases  in  which  old  age  was 
readied  without  the  appearance  of  a  tooth. 
Only  since  the  development  of  radiography  has 
it  been  possible  to  determine  definitely  the 
presence  or  absence  of  teeth  in  the  jaw. 

In  general,  it  may  be  stated  that  conditions 
leading  to  imperfect  mental  development  like- 
wise affect  the  physical  development  of  the  child, 
and  hence  are  seen  deformed  jaws  and  abnormal 
development  of  the  teeth  co-existing  with  con- 
ditions such  as  cretinism  and  other  forms  of 
idiocy.  Delayed  eruption  appears  to  be  espe- 
cially associated  with  conditions  of  mental 
aberrancy,  and  this  might  be  expected,  for  the 
brain  and  teeth  are  largely  ectodermic  structures 
and  so  liable  to  the  same  tissue  disturbances. 

(rf)  Diseases  Associated  icith  Teething. — In- 
fants weak  and  delicate  from  birtli  often  pass 
through  the  process  of  teething  without  difficulty, 
whilst  fine  and  apparently  strong  ones  may  suffer 
severely.  Under  ordinary  circumstances  the 
teeth  appear  one  after  another  at  the  usual  times, 
and  in  the  order  named,  with  so  little  apparent 
disturbance  to  the  individual  that  their  presence 
may  be  only  accidentally  discovered ;  oc- 
casionally, however,  the  child  for  some  time 
previous  to  the  eruption  of  each  group,  becomes 
restless  and   fretful,   has  an  increased   flow   of 


saliva,  and  may  be  noticed  to  press  his  knuckle 
against  the  gums.  The  child  often  sleeps  badly 
at  night  and  awakes  suddenly  with  a  cry.  K 
the  mouth  is  examined  the  gums  will  be  seen  to 
be  somewhat  swollen  and  more  than  nor- 
mally injected  \\ith  blood,  and  a  thermometer 
will  show  tliat  their  temperature  is  raised. 

AVhen  the  teeth  of  the  group  are  aU  erupted 
the  symptoms  for  the  time  usuallj'  disappear. 
An  aphthous  ulceration  of  the  gums,  tongue, 
and  cheek  is  not  uncommonly  associated  with 
the  hot,  tense,  injected,  and  tumid  gums ;  the 
patches  often  assume  a  greyish -white  colour. 
When  this  condition  occurs  over  an  erupting 
tooth,  it  has  been  given  the  name  of  "  odontitis 
infantum  ". 

In  other  cases  the  condition  of  things  is  .still 
less  favourable,  and  for  some  time  previous  to 
the  eruption  of  each  tooth  or  group  the  child 
becomes  fretful  and  irritable,  plucking  at  his 
clothing  and  hair,  or  tossing  in  his  bed ;  the 
gums  appear  hot,  and  a  transient  rise  of  tempera- 
ture at  night  is  not  uncommon.  The  child 
becomes  feverish  and  thirsty,  and,  as  West  (39) 
points  out,  will  suck  greedily  at  the  breast  and 
then  vomit  a  portion  from  the  more  than 
satisfied  stomach.  The  rubbing  of  the  gums, 
evidently  grateful  to  the  patient  in  the  slighter 
cases,  now  causes  discomfort,  and  for  this  reason 
the  infant  relinquishes  the  breast  and  may 
suddenly  cry  and  struggle. 

No  doubt  in  the  past  the  evil  effects  of  teeth- 
ing on  the  health  of  the  child  were  exaggerated 
in  their  importance,  and  diseases  occurring 
simultaneously  with  the  eruption  of  the  teeth 
were  in  many  cases  wrongly  ascribed  to  this 
as  their  cause.  On  the  other  hand,  teeth- 
ing is  undoubtedly  a  direct  or  predisposing 
cause  of  certain  ailments  in  children.  Hippo- 
crates (460-361  B.C.)  observed  the  association  of 
fever,  convulsions,  and  diarrhoea  with  teething, 
and  stated  that  children  teethe  more  easily 
when  they  have  loose  bowels  (14). 

Still's  (30,  p.  6)  opinion  may  well  be  quoted 
in  this  connection  :  "  Teething  as  an  explana- 
tion of  symptoms  is  too  often  a  cloak  for 
ignorance,  but  I  would  protest  against  the 
tendency  nowadays  to  assume  that  because 
dentition  is  a  physiological  process,  therefore 
it  is  incapable  of  di.sturbing  health ;  pregnancy 
is  a  physiological  process,  but  I  suppose  no 
one  would  deny  that  pregnancy  ma\'  disturb 
the  health  in  many  ways.  It  has  been  said 
that  teething  produces  nothing  but  teeth.  I 
venture  to  think  that  there  is  more  wit  than 
truth  in  this;  and,  at  the  risk  of  being  con- 
sidered old-fashioned  and  unscientific,  I  shall 
mention  some  of  the  disorders  to  which  in  my 
opinion  teething  may  give  rise.  I  admit  the 
difficulty  of  proof  :  we  all  know  that  coincidences 
are  apt  to  be  mistaken  for  cause  and  effect,  but 


20 


I  am  not  inclined  to  disregard  the  accumulated 
experience  of  generations  of  skilled  observers, 
who  afiirm  without  hesitation  that  dentition 
may  cause  disturbances  of  health.  How  it 
causes  these  disturbances  may  be  doubtful; 
knowing  how  profoundly  nervous  influence  can 
modify  the  functions  of  most  organs  in  the  body, 
I  see  nothing  improbable  in  the  supposition  that 
some  of  the  disorders  produced  by  dentition  may 
be  due  to  reflex  nervous  disturbance  ;  and  I  am, 
therefore,  the  more  inclined  to  think  so  when  I 
see,  as  I  sometimes  do,  an  infant  who  has 
become  '  nervous',  with  occasional  twitching, 
rolling  his  eyes  up,  and  giving  a  short,  sharp  cry, 
and  clearly  being  on  the  verge  of  convulsions, 
whilst  the  gum  is  swollen  and  tense  over  a  comin2 
tooth.  If  such  excitabiUty  of  the  nervous 
system  can  be  produced,  as  I  think  it  undoubt- 
edly can,  by  dentition,  I  see  no  reason  why  the 
transient  bronchial  catarrh,  or  the  shght  loose- 
ness of  the  bowels,  which  recur  in  some  infants 
with  the  eruption  of  the  teeth,  may  not  be  due 
to  nervous  influence." 

Still  regards  teething  as  a  trial  to  weakly 
children  predisposed  to  nervous  disorders,  but 
does  not  consider  teething  by  itself  a  cause  of 
neurosis,  such  as  epilepsy  and  petit  mal. 
Spratling  (29)  is  of  opinion  that  pathological 
teething  may  be  a  determining  cause  of  epilepsy 
in  children  of  a  neuropathic  predisposition. 
Still  believes  that  petit  mal  is  occasionally 
aggravated  by  teething.  He  considers  that 
skin  eruptions,  such  as  lichen  urticatus  and 
eczema,  are  probably  only  associated  coii- 
ditions,  or  that  the  former  is  indirectly 
connected  with  teething  through  digestive 
disturbances.  Head-nodding  (spasmus  nutans) 
with  nystagmus  is,  according  to  Still,  frequently 
coincident  in  on.set  and  cessation  with  teething, 
and  exaggerated  by  fresh  eruption  of  teeth. 
Coryza,  the  symptoms  of  which  are  watering  of 
the  eyes,  running  from  the  nose,  sneezing,  and 
coughing,  may  herald  the  eruption  of  each 
tooth  (16).  Still  has  noted  attacks  of  vomit- 
ing occurring  with  the  eruption  of  each  tooth, 
which  could  not  be  ascribed  to  any  other  cause, 
and  mentions  loss  of  appetite,  failure  to  gain 
weight,  or  a  diminution  in  the  rate  of  gain, 
as  conditions  that  may  be  due  to  dental 
irritation. 

There  is  some  doubt  whether  dribbling  of 
saliva  is  due  to  the  irritation  of  teething  or  to 
the  physiological  activity  of  the  salivary  glands 
owing  to  their  rapid  development  at  this 
period. 

A  form  of  idiopathic  salivation,  which  is 
intermittent  in  character  and  affected  by 
psychic  influences,  may  set  in  during  teething  ; 
the  dribbling  will  sometimes  continue  both 
night  and  day,  saturating  the  infant's  clothing. 
The  cause  of  this  may  be  that  the  infant  fails 


to  acquire  the  habit  of  swallowing  its  saliva, 
or  that  hypersecretion  is  maintained  beyond 
the  usual  age.  This  condition  tends  to  abate 
with  the  growth  of  the  child  and  is  to  some 
extent  amenable  to  drugs.  H.  Moon  drew 
attention  to  peculiarities  in  the  character  of 
the  saliva  in  various  digestive  and  other 
ailments. 

Edmund  Cautley  (5)  considers  that  rickets  is 
the  cause  of  many  of  the  ailments  ascribed  to 
teething,  and  regards  the  latter  as  only  an 
indirect  cau.se. 

Infants  with  swollen  and  tender  gums  are 
apt  to  bolt  their  food  ;  this  produces  irritability 
and  fretfulness,  often  wrongly  ascribed  to  hunger 
by  those  in  charge  who  give  the  child  more 
food.  The  large  quantity  of  food  in  the 
stomach,  and  the  diminislied  secretion  of  the 
digestive  juices  during  the  febrile  state,  probably 
together  contribute  to  the  diarrhoea,  or  appear 
a  more  likely  cause  than  any  influence  from 
eruption  of  teeth.  The  motions  have  the  so- 
called  chopped  spinach  appearance,  as  when 
mercury  has  been  administered. 

The  febrile  state  induced  by  painful  eruption 
renders  the  child  rather  more  liable  than  usual 
to  bronchitis,  or  wiU  aggravate  this  condition 
if  already  present.  Still  (30,  Y).  9)  remarks 
that  bronchitis  and  diarrhoea  may  be  traceable 
to  nervous  influences,  and  mentions  hi  support 
of  this  view  the  bronchial  catarrh  of  the 
asthmatic  child,  and  the  lienteric  diarrhoea  to 
which  Trousseau  gave  the  name  of  "  nervous 
diarrhoea  ",  both  admittedly  dependent  upon 
nervous  influence.  Cautley  (4)  thinks  that 
teething  may  act  as  an  exciting  cause,  in 
the  presence  of  rickets,  of  gastro-enteritis, 
catarrhal  affections  of  the  respiratory  tract, 
and  convulsions.  He  regards  the  eruption  of 
the  deciduous  canine  as  being  most  often 
associated  in  point  of  time  with  convulsions 
in  children,  but  likewise  states  that  fits  more 
commonly  occur  before  the  onset  of  teeth- 
ing. The  period  of  teething  is  that  at  which 
the  influence  of  rickets  is  most  marked,  and 
unsuitable  feeding  a  connnon  error,  both 
of  which  are  contributory  factors  to  gastro- 
intestinal disturbance,  and,  consequently,  con- 
vulsions from  intestinal  toxaemia.  Cautley  (4) 
doubts  whether  convulsions  in  infants  are  ever 
directly  due  to  reflex  dental  disturbances,  but 
mentions  that  in  a  few  cases  of  retraction  of 
the  head  no  other  explanation  was  forthcoming ; 
he  noted  that  the  eruption  of  the  molar  teeth 
was  more  often  associated  with  this  latter 
condition.  He  states  that  malnutrition  and 
reflex  irritation  predispose  to  pavor,  habit 
spasm,    tremor,    and   chorea. 

Malnutrition,  fevers,  the  exhibition  of  drugs, 
and  other  causes  of  stomatitis,  will  affect  the 
permanent  teeth,  if  these  disorders  occur  at  the 


21 


time    of    their    calcification.     Hypoplasia   pro- 
duced in  this  way  is  described  in  Chapter  III. 

Robert  Hutchison  (20)  considers  that  teeth- 
ing may  aggravate  bronchitis  and  diarrhoea  in 
children,  if  it  is  not  a  direct  cause  of  these 
ailments,  and  gives  instances  of  infants  who 
regularly  have  an  attack  of  bronchitis  or 
enteritis  as  each  tooth  appears.  Congestion 
of  the  bronchial  tubes  and  intestine,  induced 
by  ii'ritation  of  the  gums,  produces  impairment 
of  health,  and  predisposes  to  the  occurrence  of 
bronchitis  and  diarrhoea. 

Hutchison  has  noted  the  fact  that  facial 
eczema  is  apt  to  assume  an  acute  and  inflam- 
matory character  with  the  eruption  of  each 
tooth,  and  regards  this  as  probably  a  reflex  | 
process  induced  through  trigeminal  irritation. 
During  the  eruption  of  the  deciduous  teeth, 
cutaneous  eruptions  are  not  uncommon,  the  [ 
most  frequent  and  troublesome,  after  the  [ 
fugitive  and  less  important  erytliematous  raslies, 
being  eczema,  impetigo,  herpes,  and  lichen 
urticatus.  How  far  these  rashes  are  directly 
connected  with  teething,  or  merely  accidental 
at  this  period,  is  difficult  to  determine.  Impetigo 
has  been  frequently  noted  to  occur  on  the  erup- 
tion of  several  successional  teeth  ;  whilst  herpetic 
vesicles  commonly  appear  in  the  nerve  distribu- 
tion of  referred  dental  pain.  Urticaria  is  fre- 
quently associated  with  toxic  absorption  from 
the  alimentary  canal,  and  an  inflamed  mucous 
membrane  may  be  directly  or  indirectly  a  cause 
of  this  toxaemia. 

Urban  Pritchard  (27)  regards  dental  irritation 
as  a  factor  in  otalgia  and  in  suppurative  otitis 
media,  in  the  latter  both  in  its  causation  and 
in  maintaining  the  inflammatory  condition  by 
rendering  the  reparative  process  less  vigor- 
ous; Still  also  believes  that  the  comiection 
between  otorrhoea  and  teetliing  is  by  exten- 
sion of  the  catarrh  from  the  gums  to  the 
Eustachian  tube,  and  so  to  the  middle  ear. 
Both  these  authorities  ignore  the  reflex  nervous 
theory  as  a  cause  of  these  inflammatory  ear 
conditions. 

Leonard  Guthrie  (18)  considers  that  neglect 
of  oral  hygiene  is  often  responsible  for  painful 
teething,  the  tender  and  inflamed  gums  over 
the  erupting  teeth  being  further  injured  by  the 
child  biting  hard  and  dirty  objects,  or  by  those 
in  attendance  using  coarse  towels  and  imclean 
tooth-brushes.  He  rejects  the  reflex  theory, 
which  attributes  disorders  coincident  with 
teething  to  trigeminal  irritation,  on  the  ground 
that  a  child's  teeth  may  erupt  normally  while 
he  is  suffering  from  pneumonia,  meningitis,  or 
any  other  serious  illness.  If  the  gums  are 
unhealthy  or  inflamed,  pyrexia  will  result,  and 
this  may  predispose  the  child  to  catarrh  in  other 
parts ;  but  probably  the  tender  and  inflamed  gums 
are  as  frequently  a  complication  as  a  cause  of 


coincident  disorders.  The  only  condition  that 
can  be  regarded  as  a  reflex  disturbance  depend- 
ing upon  dental  irritation  is  trismus  oi  the 
muscles  of  the  mandible,  but  even  this  rarely,  if 
ever,  occurs  in  the  absence  of  inflammation,  so 
that  a  mechanical  factor  is  also  present.  The 
contraction  of  the  masseters  and  other  muscles 
of  mastication  may,  however,  be  a  true  reflex 
in  the  early  stage  of  dental  irritation,  serving 
to  protect  from  injury  the  underlying  inflamed 
gums,  much  in  the  same  way  as  the  abdominal 
muscles  contract  over  an  inflamed  vermiform 
appendix,  gall-bladder,  or  other  abdominal 
organ.  J.  G.  Turner  (38)  takes  a  view  similar 
to  Guthrie,  and  believes  that  painful  eruption 
is  largely  due  to  want  of  oral  cleanliness, 
and  states  that  teething  troubles  disappear 
in  proportion  as  cleanliness  of  the  feeding 
apparatus  is  regarded.  His  conclusions  are 
that  there  is  no  definite  evidence  of  teething 
causing  trouble,  and  no  microscopical  appear- 
ances supporting  the  view  that  tension  is  a 
cause. 

H.  A.  T.  Fairbank  (11)  describes  a  case  in 
^\■hich  symmetrical  swellings  appeared  over  the 
erupting  deciduous  lower  incisors  in  a  child 
aged  eight  months.  The  cystic  fluid  contained 
epithelial  cells,  granular  masses,  red  blood  cells, 
and  mucus ;  and  the  cyst  wall  showed  a  thick  epi- 
thelial lining,  the  j)eripheral  cells,  /.  e.  those 
in  contact  with  the  fibrous  layer  of  the  follicle, 
presenting  the  typical  columnar  arrangement  of 
the  enamel-organ.  Fairbanlc  considers  the  origin 
of  these  cysts  to  be  similar  to  that  of  the  denti- 
gerous  cyst,  and  suggests  the  name  of  "  super- 
ficial traumatic  dentigerous  cyst ",  as  explaining 
their  origin  and  pathology.  Turner  has  described 
the  microscopical  appearance  of  the  small  cystic 
swellings  over  erupting  teeth,  and  states  that 
these  are  lined  with  epithelium  of  many  layers 
in  thickness,  the  peripheral  cells  being  spheroidal 
and  those  on  the  cyst  side  stellate ;  in  fact,  their 
structure  coincides  ■«  ith  that  of  an  early  dental 
cyst.  He  believes  that  these  cysts  arise  from  the 
epithelium  of  the  enamel-organ  or  other  portions 
of  the  tooth-band. 

Cases  recorded  as  meningitis  probably  owe 
their  origin  to  the  grouping  of  such  symp- 
toms as  convulsive  twitchings,  strabismus,  and 
head-retraction,  which  are  not  uncommonly 
associated  with  teething. 

Cervical  adenitis  is  common  in  young  children 
owing  to  then.-  liability  to  catarrh  of  the  buccal 
and  naso-pharyngeal  cavities,  ^^^lile  attached 
to  a  large  Children's  Hospital,  the  writer 
systematically  examined  the  tissues  of  the  neck 
for  lymphatic  hyperplasia,  with  the  result  that 
he  found  the  lymph  glands  almost  invariably 
palpable  in  children  up  to  the  age  of  six  or 
eight  years,  whether  carious  teeth  were  present 
or  not.      Palpability  of  the  Ijmiph   glands  in 


22 


young  children  does  not  necessarily  mean 
disease  of  these  tissues,  any  more  than  the 
enlargement  of  the  spleen  or  thymus  in  child- 
hood is  indicative  of  disease  ;  but  softening  of 
their  structure,  or  tenderness  on  palpation, 
sliould  be  regarded  witli  suspicion. 

The  various  conditions  that  have  been 
ascribed  to  teething  may  be  summarized  as 
follows,  but  such  a  classification  is  not  founded 
on  a  pathological  basis,  as  these  ailments  in 
many  cases  have  but  a  remote  and  doubtful 
connection  with  teething. 


(1)  Alimentary  System. 
Salivation. 

j  Simple. 
Stomatitis^  Aphthous. 

[ulcerative. 
Eruption  cysts. 
Trismus  of  the  jaws. 
Otitis  media. 
Gastro-enteritis. 
Enteritis. 

Malnutrition  (rickets). 
Intestinal  toxaemia. 
Diarrhoea. 
Constipation. 
Vomiting. 
Adenitis  (cervical). 

(2)  Bespiratory  System. 
Bronchitis. 

Cough. 

Shortness  of  breath. 


(3)  Nervous  System. 
Sleeplessness. 
Screaming     attacks 

(pavor). 
Irritability. 
Convulsions. 
Head-rolling. 
Head-retraction. 
Epilepsy. 
Petit  mal. 
Habit-spasm. 
Tremor. 
Chorea. 
Strabismus. 
Meningitis. 

(4)  Cutaneous  System. 

Facial  eczema. 

Erythema. 

Impetigo. 

Herbes. 

Lichen  urticatus. 


(5)   Urinary  System. 
Polyuria. 
Anuria. 
Dysuria 

Whilst  there  is  no  speciiic  for  teething,  much 
may  be  done  to  allay  its  symptoms,  care  being 
taken,  however,  that  they  are  not  wrongly 
ascribed  to  this  cause,  when  in  reality  another 
and  more  serious  origin  is  present.  Processes 
are  physiological  only  when  normally  performed, 
and  may  become  pathological  by  surgical  inter- 
ference "or  when  natural  means  are  frustrated. 
vSo  long  as  the  former  conditions  are  maintained, 
the  less  nature  is  interfered  with  the  better. 
When  groups  of  teeth  are  being  erupted,  it  is 
advisable  to  avoid  weaning,  or  other  important 
alterations  in  the  child's  diet;  exposure  to 
changes  in  temperature  by  alteration  in  cloth- 
ing must  be  guarded  against ;  and  the  post- 
ponement of  vaccination  may  also  be  desirable. 

Strict  attention  should  be  paid  throughout 
to  the  cleansing  of  feeding-bottles,  which 
should  be  of  the  modern  pattern.  The  state 
of  the  cliild's  mouth  requires  care,  and  he  must 
be  restrained  from  sucking  undesirable  objects. 


The  gums  should  be  brushed  after  food  with  a 
very  soft  tooth-brush  or  wiped  with  clean  lint 
or  wool,  glycerine  of  borax,  to  which  gr.  .x  of 
chlorate  of'  potash  are  added  for  each  ounce 
of  glycerine,  being  used  if  any  inflammation  of 
the  gums  is  present ;  but  this  may  be  very 
difficult  to  effect  with  fractious  infants.  If  the 
gum  is  inflamed  or  ulcerated  over  an  erupting 
tooth,  potassium  chlorate  should  be  given 
internally  in  two-grain  doses;  this  drug  is 
excreted  in  the  saliva  and  so  has  a  local  action. 
As  soon  as  the  teeth  have  erupted,  a  dentifrice 
of  prepared  chalk  may  be  used. 

Ambroise  Pare  (1510-1599)  was  the  first  to 
advocate  lancing  of  the  gums  for  painful 
eruption  of  the  teeth,  and  the  advisabihty  of 
this  method  of  treatment  has  been  a  source  of 
discussion  ever  since.  If  the  gums  are  swollen, 
tense,  and  congested,  we  may  afford  some  relief 
by  incising  them,  the  gum  being  divided  down 
to  the  enamel  of  the  tooth.  A  useful  plan  is  to 
make  a  crucial  incision  and  free  the  flaps  so 
formed  from  the  crown  of  the  tooth.  Incising 
the  gum  is  not  of  much  value,  except  for  the 
immediate  relief  of  congestion,  as  unless  the 
incision  allows  the  crown  of  the  tooth  to  pene- 
trate, the  edges  of  the  incision  will  fall  together 
and  unite  by  granulation  tissue.  In  the  front 
of  the  mouth  the  incision  can  be  confined 
almost  entirely  to  the  anterior  aspect  of  the 
gum,  as  this  is  the  position  at  which  these  teeth 
erupt.  If  the  gum  is  well  separated  and  raised 
from  the  crown  of  the  tooth ,  there  is  no  need  to 
remove  the  freed  portion.  In  performing  this 
operation,  the  blade  of  a  small  scalpel  should 
be  protected  up  to  half  an  inch  from  its  point 
by  a  strip  of  adhesive  plaster ;  or  a  special  gum 
lancet  may  be  employed.  The  short  hatchet- 
blade  lancet  is  useful  in  freeing  a  tooth  at  the 
back  of  the  mouth  or  in  dealing  with  a  trouble- 
some child.  The  child's  head  should  be  carefully 
steadied  and  its  hands  held  to  its  side  A  nurse 
can  hold  an  infant  in  her  lap  in  such  a  \\  ay  that 
the  child's  head  rests  on  her  thigh,  and  if  the 
nurse  raises  her  foot  on  to  a  stool  or  chair,  her 
hands  are  free  for  steadying  the  cliild's  body  and 
arms ;  the  infant's  head  may  be  best  looked  after 
by  the  operator.  A  method  that  gives  greater 
control  over  the  lower  jaw  is  for  the  operator  to 
have  the  child  in  his  lap,  with  the  head  against 
his  chest  and  the  hands  and  feet  held  by  a  nurse. 
The  operator's  left  thumb  is  placed  in  the  child's 
mouth  upon  the  tongue,  and  his  index  finger  in 
the  cheek  sulcus  for  a  tooth  on  the  right  side 
(the  thumb  and  finger  are  reversed  for  the  left 
side),  and  the  remaining  fingers  support  the 
chin.  By  this  means  the  head  is  steadied,  the 
tongue  is  controlled,  and  the  lip  is  held  out  of 
the  way.  The  operation  of  lancing,  however, 
should  be  quite  exceptional ;  its  general  employ- 
ment, as  was  the  case  some  half  a  century  ago. 


23 


was  undoubtedly  cruel  and  uncalled  for ;  yet 
there  is  a  danger  in  the  present  day  of  a  valuable 
and  simple  means  of  aUajdng  distressing 
symptoms  being  for  fashion's  sake  discarded. 
The  older  method  of  applying  a  leecli  at  the 
angle  of  the  jaw  has  been  almost  entirely  super- 
seded bj-  lancing.  The  exliibition  of  bromides 
is  useful  to  allay  irritability,  induce  sleep,  and 
ward  off  possible  convulsions. 

Tiie  greatest  circumspection  on  the  part  of 
the  practitioner  is  requisite  in  the  treatment  of 
diarrhoea  accompanying  teething,  and  in  tlie 
absence  of  any  traceable  errors  in  diet  or  in  the 
daily  routine  of  the  infant,  the  practitioner 
must  look  else^\  here  for  a  cause ;  in  the 
meantime  it  will  be  more  prudent  merely  to 
restrain  the  condition  within  moderate  bounds. 
The  older  authorities  regarded  the  diarrhoea 
accompanying  teething  as  an  effort  of  nature 
to  relieve  local  inflammation,  much  in  the  same 
way  as  sahvation  was  regarded,  and  they 
thought,  therefore,  that  it  ought  not  to  be 
actively  checked.  Should  there  be  no  other  ap- 
parent cause  for  the  diarrlioea,  uuich  assistance 
wiU  be  afforded  by  leaining  whether  on  previous 
occasions  such  conditions  ]_  re  vailed,  and  passed 
off  when  the  process  of  eruption  was  aecom- 
pHshed.  The  time  of  teething  is  one  of  transi- 
tion, a  uniform  and  bland  diet  is  changed  for 
one  of  greater  variety,  and  the  febrile  attacks, 
diarrhoea,  and  vomiting,  so  rifeduringthisperiod, 
are  more  satisfactorily  explained  by  indigestion 
than  by  any  occult  influence  of  tooth-cutting. 
Careful  inquiries  should  be  made  into  the 
conditions  under  which  the  child  is  receiving 
its  nutriment ;  if  from  the  breast,  tlien  whether 
circumstances  have  occurred  that  could  alter 
the  character  of  the  milk,  or  whether  the  child 
is  allowed  the  breast  too  frequently  or  at 
irregular  intervals ;  if  by  hand,  then  whether 
any  changes  have  been  made  in  the  character 
of  the  food  or  in  its  consistency.  The  cow's- 
milk,  if  that  has  been  employed,  may  have  been 
obtained  from  another  source,  or  supplied  in 
too  large  quantities,  or  insufficiently  diluted — 
both  very  common  errors  in  the  nurture  of 
infants.  The  reader  is  referred  to  Goodhart 
and  vStill  (16),  for  an  excellent  treatise  on 
infant -feeding,   wet-nursing,  and  weaning. 

When  there  is  no  apparent  cause  for  the 
diarrhoea,  the  child  should  be  given  a  dose  of 
castor  oil,  which  may  be  repeated  if  necessary. 
Threatenings  of  convulsion,  such  as  contraction 
of  the  hands  and  feet,  may  be  treated  by  giving 
the  child  a  mild  aperient,  e.  g.  calomel  or 
hydrargyrum  cum  creta  (gr.  ij)  with  pulvis  rhei 
(gr.  ij).  Nervous  irritability  and  restlessness 
may  be  allayed  by  giving  three  to  fiv^e  grains 
of  Ijromide  of  j)otassium  or  sodium.  Citrate  of 
potassium  used  two  or  tliree  times  a  day  is  a 
useful  saline  diuretic  for  inflamed  gums. 


2.  Development  of  the  Jaws  and  Teeth.— The 
maxilla  and  mandible  increase  in  size  by 
additional  growth  to  the  outer  surface  and 
borders  of  these  boties,  especially  at  the  lines 
of  sutures,  where  the  uniting  fibro-cellular  tissue 
forms  an  elastic  bond  of  union  allowing  of  growth 
and  expansion. 

In  some  parts  of  the  jaws  growth  is  more 
active  than  at  other  parts.  Absorption  and 
deposition  of  bone  may  take  place  sinuiltane- 
ously  on  opposite  sides  of  the  jaw,  completely 
changing  its  form.  Owing  to  some  such  means 
the  ascending  ramus  of  the  mandible  as- 
sumes an  almost  vertical  position  in  the  adult ; 
absorption  of  its  anterior  margin  carries  this 
process  of    bone  backwards  from  the  region  of 


Fig.  37. — MaxUla  and  mandiblo  at  the  period  of  com- 
mencement of  teething,  sliowing  the  incisor  teeth 
erupting  and  the  remaining  deciduous  teeth  lying 
in  their  crypts.  Tlie  two  halves  of  the  mandible 
are  incompletely  united  by  bone  (from  Tomes). 

the  first  permanent  molars  to  a  point  well 
behind  the  second  permanent  molars,  while 
at  the  same  time  deposition  of  bone  on  its 
posterior  surface  raises  the  a.scending  ramus 
from  a  nearly  liorizontal  to  an  almost  vertical 
position ;  in  this  way  the  angle  of  the  jaw  is 
changed  from  an  obtuse  to  a  right  angle. 

The  growth  of  all  bones  is  interstitial  (end- 
osteal) and  superficial  (periosteal),  so  that  the 
trabeculae  of  the  portion  first  formed  are  being 
continually  rearranged,  until  the  whole  bone 
may  be  said  to  be  "  soHdified ".  The  term 
"  bone-currents  ",  if  not  a  correct  one,  is 
expressive  in  describing  the  moulding  process 
and  ossification  of  a  bone ;  and  the  symmetrical 
and  graceful  curves  of  the  trabeculae  seen  on 
section  of  a  bone  seem  to  indicate  that  the 
term  is  not  altogether  fanciful,  and  that  some 


24 


such  flowing  or  streaming  movement  does 
actually  occur  in  the  pre-ossified  and  plastic 
stage,  determining  the  ultimate  shape  and 
structure  of  a  bone,  or  in  the  case  of  the  jaws, 
bringing  up  the  teeth  into  aUgnment  and  finally 
into  occlusion. 

At  the  period  of  the  commencement  of  teeth- 
ing (i.  e.  at  about  the  seventh  month),  the 
alveoli  lodging  the  deciduous  incisors  have 
reached  their  maximum  development,  while 
those  enclosing  the  molar  teeth  are  still  in 
active  growth  (see  Fig.  37).  The  lower 
border  of  the  manchble  becomes  less  convex 
owing  to  the  development  of  the  mental 
prominence  and  angle  of  the  jaw.  The  condy- 
loid, coronoid,  and  angular  f)rocesses  have 
opened  out,  although  still  bearing  much  the 
same  relation  to  one  another.  The  body  of 
the  mandible  has  increased  in  size ;  its  extra- 
oral  portion  is  dependent  for  its  growth  and 
development  on  muscular  action,  its  intra- 
oral or  alveolar  portion  subserves  the  purpose 
of  protecting  and  carrying  the  teeth,  and  de- 
pends chiefly  on  the  functioning  of  these  as 
a  stimulus  to  its  development.  The  upper 
jaw  may  similarly  be  divided  into  a  body  and 
alveolar  portion ;  muscular  action,  however, 
plays  but  a  small  part  in  the  growth  of  its  body, 
this  depending  chiefly  on  the  pressure  in  its  air- 
sinuses  brought  about  by  efficient  respiration, 
and  the  development  of  the  brain  and  its 
prolongations,  the  optic  and  olfactory  organs. 
The  growth  of  the  tongue  and  the  pressure  it 
exerts  are  factors  common  to  the  development 
of  both  jaws ;  although  it  has  been  stated  that 
in  cases  of  absence  of  the  tongue  the  jaws 
develop  normally.  The  influence  of  mastication 
on  the  development  of  the  jaws  and  their 
surrounding  parts  is  probably  brought  about 
mainly  by  the  increased  blood  and  lymph 
supply  induced  by  muscular  contraction. 
Thornton  Carter  lays  great  stress  on  the 
eruption  and  use  of  the  teeth  as  a  factor  deter- 
mining the  growth  of  the  jaws,  and  considers 
that  the  ultimate  shape  of  the  jaws  is  entirely 
dependent  on  their  physiological  use  as  tooth- 
carrying  structures.  He  mentions  an  important 
point,  which  has  not  previously  been  empha- 
sized, viz.  that  the  shape  of  the  jaws  and  the 
position  of  the  condyle  are  entirely  subservient 
to  the  development  and  function  of  the  muscles 
that  move  them,  and  that  these  again  are 
subservient  to  the  function,  and  so  to  the  shape, 
of  the  teeth. 

In  vertebrates  the  jaws  may  be  roughly 
divided  into  two  groups,  one  including  animals 
whose  jaws  are  adapted  for  seizing  and  cutting 
food;  and  the  other,  those  whose  jaws  are 
adapted  for  mastication.  In  the  former  the 
condyle  is  always  on  a  level  with  the  masticatory 
surfaces  of  the  teeth,   but   in   the  latter  it  is 


necessary  that  the  molar  region  should  approxi- 
mate simultaneously  and  not  as  the  blades  of 
a  pair  of  scissors,  and  therefore  the  condyle 
is  always  situated  in  a  plane  well  above  the 
occlusal  plane  of  the  teeth.  So  it  is  in  the  case 
of  the  development  of  the  human  jaw  after 
birth ;  if  the  diet  is  such  that  the  deciduous 
molars  are  actively  functional,  there  will  be 
considerable  elevation  of  the  condyle  of  the 
mandible  above  the  occlusal  plane  of  the  teeth, 
whilst  if  the  habit  of  mastication  is  neglected 
and  the  teeth  are  used  merely  for  cutting  pur- 
poses, there  will  be  but  feeble  development  of 
the  ascending  ramus  and  the  condyle  will  not 
be  elevated  far  above  the  occlusal  plane. 

The  body  of  the  maxilla  by  its  increase  in 
size  raises  the  floors  of  the  nasal  and  orbital 


Fig.  38. — Diagram  representing  a  mandible  at  birtli 
superimposed  upon  an  adult  mandible,  to  show 
the  directions  in  which  growth  of  bone  has  taken 
place  (from  Tomes). 

cavities.  The  nasal  cavities  and  their  amiexes 
rapidly  increase  in  size  as  respiration  is  estab- 
lished ;  the  orbital  cavity  and  the  skull  increase 
pari  jmssu  with  the  growth  of  their  contained 
viscera.  Although  the  eye-ball  grows  but  httle 
after  birth,  there  is  considerable  development 
of  the  fatty  envelope  surrounding  it.  The 
cavity  of  the  maxillary  sinus  at  the  period  of 
the  commencement  of  teething  would  barely 
accommodate  an  orange-pip. 

The  growth  of  the  mandible  has  been  shown 
to  be  chiefly  due  to  the  deposit  of  bone  on  the 
outer  surface  of  its  body,  and  on  the  posterior 
surface  of  its  ascending  ramus.  These  facts 
have  been  carefully  determined  by  Tomes,  from 
measurements  taken  of  the  jaws  at  different 
ages,  and  well  illustrated  in  a  figure  in  wliich 
he  shows  a  jaw  at  birth  suj)primpf)sed  upon  that 


25 


of  an  adult  jaw  (see  Fig.  38).  Thus  the  trans- 
verse distance  between  the  Ungual  surfaces  of 
the  second  deciduous  molars,  shortly  before 
they  are  shed,  is  almost  equal  to  that  between 
their  successors  at  a  far  later  period  ;  and  a  line 
drawn  back\\ards  from  a  point  intermediate 
between  the  posterior  surfaces  of  the  central 
incisors  to  bisect  the  former  line  is  of  nearly 
the  same  length  in  a  child  as  in  an  adult,  but 
if  this  line  be  prolonged  to  the  front  of  the  jaw, 
so  as  to  include  its  thickness,  a  greater  chsparity 
is  noted.  Grevers  (17)  found  an  increase  of 
only  2  mm.  or  1  mm.  on  each  side  in  comparing 
the  transverse  measurements  of  an  adult 
mandible  with  that  of  a  child.  He  states  that 
the  lower  jaw  has  almost  attained  its  full 
growth  in  width  at  the  age  of  five  years ;  he  also 
remarks  that  the  palate  does  not  show  much 
increase  in  height  after  the  twelfth  year. 

For  a  time  the  vault  of  the  skull  increases 
in  a  greater  ratio  than  its  base,  so  that  the 
dental  arches  do  not  possess  the  same  promi- 
nence as  they  did  at  an  earlier  age.  The 
alveoli  are  no  sooner  formed  than  they  begin 
to  sho\\'  retrogressive  changes,  appearing  in 
the  dried  skull  as  absorption  of  the  anterior 
surfaces  of  the  incisor  sockets,  and  in  the  living 
subject  as  the  eruption  of  these  teeth  through 
the  gums.  At  the  period  of  the  commencement 
of  teething  the  deciduous  incisors  are  complete, 
except  for  their  roots,  and  the  croons  of  the 
molars  and  canines  are  fidly  formed  (see  Fig. 
27).  kSome  of  the  permanent  teeth  are  partly 
calcified ;  thus  traces  of  calcification  can  be 
detected  in  the  incisors  and  canines,  and  the 
five  cusps  of  the  first  molars  are  united  by  a 
ring  of  calcified  material,  the  external  cusps 
being  more  developed  than  the  internal  cusps. 
The  crowns  of  the  upper  permanent  molars 
face  down\^ards  and  backwards ;  whilst  the 
corresponding  teeth  in  the  lower  jaw  look 
upwards,  forwards,  and  inwards.  Symington 
and  Rankin  (31)  have  shown  by  radiographs 
the  condition  of  the  teeth  from  birth  up  to  the 
sixteenth  year,  thus  giving  a  fairly  complete 
history  of  calcification  of  the  teeth  after  birth. 
This  investigation  was  carried  out  by  means  of 
median  sections  through  the  head,  and  shows 
that  multi-cuspidate  teeth  calcify  by  independent 
deposits  on  the  apices  of  the  dental  papilla ; 
otiier  phenomena  also  have  been  elucidated  or 
confirmed. 

It  may  be  broadly  stated  that  calcification 
of  the  deciduous  and  permanent  teeth  has 
extended  to  the  apices  of  their  roots  within 
two  years  from  the  time  of  their  complete 
eruption  ;  but  that  a  fiu'ther  period  of  a  year 
or  t\\o  elapses  before  the  entire  thickness  of  the 
root  has  calcified. 

At  the  end  of  the  first  year  the  roots  of  the 
deciduous  incisors  are  delineated  to  half  their 


extent,  those  of  the  first  deciduous  molars  are 
well  advanced  in  their  formation,  while  those  of 
the  second  molars  and  canines  are  quite  dis- 
cernible (see  Figs.  27,  3i»).  The  anterior 
wall  of  the  alveoli  of    the  incisors  is  deficient, 


Fig.  39. — The  maxilla  and  uiandibk-  at  tlie  ind  of  thu 
first  year.  The  outer  alveolar  plate  has  been 
removed  to  show  the  deciduous  and  some  of  the 
permanent  teeth  in  their  crypts.  (Odontoluqiral 
Museum,  Roijal  College  of  Suiyeons  of  England.) 

allowing  the  cro\\ns  of  these  teeth  to  appear 
through  the  gum  (see  Fig.  37).  The  alveoli  of 
the  molars  and  canines  are  imperfect  at  their 
orifices,  but  the  gum  over  their  crowns  is  still 
intact,  although  prominent  over  the  first  molars. 


Fig.  4U. — Tlie  maxilla  and  mandible  at  thr  i-nd  of  the 
second  year.  The  outer  alveolar  plate  has  been 
removed  to  show  the  extent  of  calcification  of  the 
roots  of  the  deciduous  teeth  and  of  the  crowns  of 
the  permanent  teeth.  (Orlontological  Museum, 
Royal  College  of  Surgeons  of  England.) 

The  crowns  of  the  first  permanent  molars  are 
calcified  to  half  their  extent,  those  of  the 
incisors  to  a  less  degree,  and  only  the  tip  of 
the  canines.  The  bony  crypt  of  the  first  upper 
permanent  molars  is  situated  in  the  tuberosity, 
and  these  teeth  are  beginning  to  come  into 
alignment     with     the    deciduous    teeth.     The 


26 


maxillary  sinus  extends  outwards  to  the  anterior 
extremity  of  the  zygomatico-maxillary  suture 
and  has  increased  in  height,  thus  separating  the 


Fig.  41. — Tho  maxilla  and  mandible  between  the  third 
and  fourth  years.  The  outer  alveolar  plate  has 
been  removed  to  show  the  amount  of  calcification 
of  the  permanent  teeth.  (Odontological  Museum, 
Royal  College  of  Surgeons  of  England.) 

orbital  and  alveolar  processes.  The  ascending 
ramus  of  the  mandible  consists  of  a  quadrilateral 
plate  of  bone,  and  the  condyloid  process  rises 
almost  vertically  from  it.  Both  the  jaws  have 
gained  in  weight,  and  a  basal  element  may  now 
be  said  to  exist  in  the  mandible. 

At  the  end  of  the  second  year  the  deciduous 
dentition  is  completed,  except  for  the  apices  of 
the  canines  and  second  molars  (see  Figs.  27, 
40).  In  the  permanent  dentition  the  ciowns 
of  the  first  molars  are  formed,  and  a  large 
portion  of  the  cro^Tis  of  the  incisors  and  canines. 
The  alveolar  margin  of  the  jaw  extends  behind 
the  crypt  of  the  first  permanent  molar  in 
preparation  for  the  socket  of  the  second  per- 
manent molar.  The  maxillary  sinus  extends 
outwards  to  the  infra-orbital  foramen  and  above 
the  first  permanent  molar  germ.  The  angle  of 
the  mandible  is  approaching  a  riglit  angle.  The 
ascending  ramus  has  grown  rapidly  to  com- 
pensate for  the  alveolar  growth  in  the  incisor 
region,  and  so  allows  a  sufficient  space  for 
the  permanent  molars  to  erupt  into  before 
coming  into  occlusion ;  as  this  growth  has 
necessarily  been  chiefly  in  the  vertical  direc- 
tion, it  has  probably  arisen  from  the  epiphyseal 
bone  in  the  region  of  the  condyle  (Kollikcr). 
James  and  Pitts  (21)  believe  that  denudation 
of  the  gum  is  an  important  factor  in  the  final 
eruption   of   the   teeth,  and   comes   into   play 


earher  in  some  of  the  teeth  than  in  others  ;  thus, 
the  first  mandibular  molars  are  often  in  partial 
occlusion  after  just  piercing  the  gum,  and  the 
apparent  advancement  of  these  teeth  may  be 
due  largely  to  retrogression  of  the  overlying 
gum  tissue  by  absorption  brought  about,  as  they 
believe,  by  the  stimulus  of  mastication. 

At  the  end  of  the  third  year  the  teeth  of  the 
deciduous  dentition  are  completed,  and  in  the 
permanent  dentition  the  crowns  of  the  incisors 
and  canines  are  calcified  and  the  first  molars 
are  beginning  to  show  root-formation  (see  Figs. 
27,  41).  Calcification  in  the  first  premolars 
has  commenced,  but  is  not  yet  visible  in  the 
second  premolars.  The  crypts  of  the  second  per- 
manent molars  are  in  process  of  development. 

At  the  end  of  the  fourth  year  calcification 
can  be  detected  in  the  second  premolars  and 
second  molars,  and  elsewhere  has  advanced  in 
its  extent  (see  Figs.  27,  41).  The  crypts  of  the 
second  permanent  molars  are  present  in  the 
maxillary  tuberosity  and  face  almost  directly 
backwards  ;  those  of  the  mandible  are  contained 
in  an  extension  backwards  of  the  alveolar 
margin.  At  this  period  representatives  of  every 
tooth  in  both  dentitions  should  be  present. 

At  the  sixth  year  the  deciduous  teeth  are 
slightly  spaced,  owing  to  the  growth  of  the  jaws 
since  the  teeth  came  into  alignment.  The 
deciduous  teeth  remain  complete  for  only  a 
short  period,  as  absorption  commences  almost 
as  soon  as  they  are  fullv  formed  and    can  be 


Fig.  42. — Tlie  maxilla  and  mandible  at  the  sixth  year- 
The  outer  alveolar  plate  has  been  removed  to  show 
the  extent  of  calcification  of  the  permanent  teeth. 
(Odontological  Museum,  Royal  College  of  Surgeons 
of  England.) 

traced  at  this  period  in  the  roots  of  the  deciduous 
incisors.  The  crypts  of  the  first  permanent 
molars   are  widely  open   and    their  contained 


27 


teeth  have  become  partly  extruded  through, 
the  overlying  gum  alone  remaining  intact.  The 
crowns  of  the  incisors  are  complete,  except 
towards  the  cervical  margin,  where  the  enamel 
may  present  the  dull,  lustreless,  appearance  indi- 
cative of  incomplete  calcification  (see  Figs.  27, 
42).  The  canines  and  premolars  are  less 
advanced  in  tlieir  calcification,  while  the  second 
permanent  molars  show  only  a  cap  of  calcified 
tissue.  The  crypts  of  the  second  upper  molars 
are  assuming  a  more  vertical  position,  and  the 
bone  covering  them  is  incomplete.  The  roots 
of  the  first  permanent  molars  are  formed 
throughout  half  their  length,  those  of  the 
incisors  are  merely  indicated,  while  the  crowns 
of  the  remaining  teeth  are  incomplete.     There 


Fig.  43. — The  maxilla  and  mandible  at  the  seventh 
year.  The  outer  alveolar  plate  has  been  removed 
to  show  the  relation  of  the  deciduous  to  the 
permanent  teeth  and  of  the  latter  to  each  other. 

is   a   fullness   in   the   maxillary  incisor  region, 
indicating  the  presence  of  these  teeth. 

The  position  of  the  crypts  of  the  permanent 
teetli,  and  their  relation  to  one  another,  as  well 
as  to  the  deciduous  dentition,  can  be  more  easily 
learned  by  studying  a  skull  of  this  period  than 
from  any  long  and  detailed  description  (see  Fig. 
43).  A  few  salient  points  may,  however,  be 
mentioned.  The  crj'pts  of  the  incisors  are 
oblique,  owing  probably  to  growth  of  bone  in 
the  inter-pre-maxillary  suture,  and  those  of  the 
upper  jaw  extend  to  the  floor  of  the  nose.  In 
both  jaws  they  are  partly  covered  in  front  by 
the  roots  of  their  predecessors.  The  lateral 
incisor  crypts  are  placed  somewhat  internal  to 
the  dental  arch,  while  those  of  tlie  canine  are 
situated  outside  the  arch  and  deeper  in  the 
jaw.  The  premolar  crowns  are  embraced  by 
the  roots  of  their  predecessors  and  lie  in  the 
same  crypts — a  fact  of  wliich  the  operator 
avails    himself    when    the    removal    of    these 


teeth  prior  to  their  eruption  is  indicated ;  the 
premolars  are  directed  slightly  inwards,  the 
second  more  markedly  than  the  first.  The 
obhquity  of  the  incisor  crjrpts  and  the  vertical 
direction  of  those  of  the  premolars  produce  an 
angular  space  on  each  side  of  the  jaw  into  which 
the  permanent  canine  erupts.  The  crypts  of  the 
first  and  second  molars  lie  behind  those  of  the 
premolars,  those  for  tlie  second  molars  being 
more  deeply  embedded  ui  the  jaw.  A  vertical 
section  of  the  jaw  behind  the  second  molar 
region  may  show  a  small  circular  cavity,  for 
the  lodgement  of  the  uncalcified  tliird  molar 
germ. 

The  portion  of  the  mandible  below  the  in- 
ferior alveolar  canal  has  nearly  reached  its  full 
development,  but  the  portion  above  the  canal 
undergoes  change  until  adult  life. 

The  transition  from  the  deciduous  to  the 
permanent  dentition  (36)  is  provided  for  by 
the  curve  occupied  by  the  occlusal  surfaces  of 
the  premolars  and  molars,  known  as  the  curve 
of  occlusion  or  the  curve  of  Spec.  The  relative 
position  of  the  buccal  and  lingual  cusps  of  these 
teeth,  and  the  form  of  the  mandibular  fossa 
determine  the  patli  taken  by  the  mandibular 
condyles  in  their  movement.  There  is  no  inter- 
ruption of  mastication  during  the  transition  from 
the  deciduous  to  the  iiermanent  dentition,  as 
this  is  provided  against  by  the  early  eruption 
of  the  first  permanent  molars,  which,  together 
with  the  deciduous  molars,  act  as  pillars  in 
supporting  the  jaws,  while  tooth-change  is 
occurring  in  the  incisor  region ;  subsequently 
the  incisor  teeth  and  the  first  permanent 
molars  allow  the  deciduous  molars  to  be  re- 
placed by  their  successors,  the  premolars. 
Mastication  is  carried  on  up  to  the  age  of  ten  by 
the  deciduous  teeth,  reinforced  at  the  age  of 
six  by  the  first  permanent  molars.  It  is, 
therefore,  of  the  greatest  importance  to  keep 
the  first  dentition  eflficient  during  this  period. 

3.  Absorption  of  the  Teeth. — The  deciduous 
dentition  only  remains  in  a  condition  of  com- 
plete development  for  a  period  of  about  a 
year,  for  as  soon  as  the  roots  of  the  second 
deciduous  molar,  the  last  of  the  series,  are 
completed,  those  of  the  teeth  fu-st  erupted 
show  signs  of  absorption.  Absorption  of  the 
roots  of  the  deciduous  teeth  occupies  about 
three  j'ears  for  its  completion.  As  the  root 
of  a  tooth  disappears,  its  puljj  undergoes 
fibrous  degeneration.  Tomes  (34)  beUeves  that 
the  pulp  of  the  deciduous  tooth  ^\•hen  exposed 
by  absorption  may  assume  the  function  of  an 
absorbent  organ. '  Absorption  commences  on 
the  surfaces  of  the  deciduous  teeth  adjacent 
to  their  successors,  *.  e.  on  the  lingual  surface 
of  the  incisors  and  canines,  and  on  the  under 
surface  of  the  deciduous  molars. 

Several    views    have    been    put    forward    to 


28 


explain  the  process  by  which  the  roots  of  the 
deciduous  teeth  become  removed  and  the  teeth 
themselves  are  thrown  off;  some  of  these  views, 
not  being  in  keeping  with  present  knowledge 
of  pathology,  can  be  omitted.  The  views  that 
receive  most  support  are — ■ 

(1)  That  the  absorption  of  the  deciduous 
tooth  is  brought  about  by  the  pressure  of  its 
successor. 

(2)  That  absorption  is  brought  about  by 
the  presence  of  large  multi-nucleated  cells,  this 
group  or  mass  of  cells  being  designated  an 
absorbent  organ. 

In  support  of  the  first  view  is  the  fact  tliat 
absorption  is  usually  most  marked  on  surfaces 
adjacent  to  the  succeeding  tooth.  This  view, 
however,  is   opposed   by  the   following  clinical 

facts — 

A  partition  of  bone  forming  the  floor  of  the 
deciduous  socket  not  infrequently  persists 
between  the  deciduous  and  jiernianent 
teeth,  and  may  be  of  some  considerable 
thickness  when  the  former  are  exfoliated 
before  their  successors  are  ready  to  appear. 

The  deciduous  teeth  sometimes  maintain 
their  places  to  the  exclusion  of  their 
successors,  and  show  no  signs  of  absorption 
even  when  their  successors  are  apparently 
in  contact  with  them. 

There  is  an  absence  of  any  correlation  in 
time  between  the  absorption  of  the  decidu- 
ous teeth  and  the  eruption  of  the  permanent 
teeth  into  the  space  so  formed ;  if  pressure 
alone  were  responsible  there  w  ould  probably 
be  some  relationship  of  the  kind. 

The  second  view  gains  support  from  the  fact 
that  these  groups  of  cells  may  be  identified  under 
the  microscope  in  situations  in  which  absorption 
is  taking  place,  whether  of  bone  or  dental 
tissue.  The  tissue  undergoing  absorption  bears 
a  festooned  appearance,  and  in  the  depressions 
(Howship's  lacunae)  a  soft  vascular  tissue, 
consisting  almost  entirely  of  large  multi- 
nucleated cells,  can  be  observed.  In  the 
deciduous  teeth,  where  the  process  is  a  normal 
one,  the  absorption  commences  in  the  region 
of  the  apex  of  the  root,  apparently  whether 
the  successor  is  present  or  not ;  but  when  the 
process  is  pathological,  as  in  the  iJermanent 
teeth,  absorption  commences  in  the  region  of 
irritation,  whether  this  is  caused  by  pressure 
from  an  abnormally  situated  tooth  or  by 
inflammation.  The  method  by  which  the 
giant-cells  produce  the  absorption  is  unknown. 
Black  believes  that  the  absorbent  organ  secretes 
or  elaborates  a  digestive  juice  or  ferment, 
which  either  digests  the  dental  tissues  or  pre- 
pares  them   in   some   way   for   absorption ;   as 


de\'italized  teeth  are  not  readily  absorbed,  he 
beUeves  that  the  living  pulp  of  the  tooth  may 
play  an  important  part  in  the  process.  Cases 
have  been  brought  forward  from  time  to  time 
showing  absorption  of  the  deciduous  teeth  in  the 
absence  of  their  successors.  T.  E.  Wills  (40) 
records  the  case  of  a  girl,  aged  fourteen,  who 
showed  persistence  of  a  second  deciduous  molar 
\\ith  extreme  absorption  of  its  roots,  and  yet 
radiography  showed  entire  absence  of  its 
successor. 

G.  Fischer  (13)  has  carefully  described  the 
microscopical  changes  occurring  during  absorp- 
tion, and  the  following  is  a  brief  abstract  of 
his  work  :  The  first  phenomenon  of  absorption 
is  hyperaemia  of  the  dental  follicle ;  this  is 
followed  by  the  appearance  of  a  dense  capillary 
plexus,  and  numerous  osteoclasts  and  giant- 
cells  at  the  periphery  of  the  bony  socket,  which 
"  eat  "  into  the  surrounding  bone.  The  ab- 
sorjation  spreads  by  way  of  the  Haversian 
canals  and  its  extent  is  governed  by  the  growth 
of  the  dental  germ ;  besides  absorption  or 
dissolution,  a  less  active  building  up  of  bone, 
cementum,  and  dentine  also  occurs,  but  this 
newly  formed  tissue  finally  disappears.  Fischer 
believes  that  the  giant-cells  are  derived  from 
the  endothelium  of  the  vessel  walls,  and  perish 
after  reaching  a  certain  stage  of  development, 
po.ssibly  being  assimilated  by  invading  poly- 
nuclear  leucocytes. 

The  above  views  of  the  causation  of  absorp- 
tion of  the  deciduous  teeth  may  have  some  cor- 
relation, ?'.  e.  the  pressure,  or  even  the  presence, 
of  the  subjacent  tooth  may  determine  the 
formation  of  the  absorbent  organ,  which  per- 
forms the  osteoclastic  function.  Against  this 
view  nuist  be  placed  the  fact  that  the  roots  of 
the  deciduous  teeth  are  sometimes  found  fully 
absorbed  in  the  ajaparent  absence  of  their 
successors.  The  fact  that  the  root  of  a  necrosed 
deciduous  tooth  may  show  no  signs  of  ab- 
sorption does  not  render  the  above  views 
untenable,  as  nature  employs  different  methods 
in  performing  jDhysiological  and  pathological 
functions. 

11.  THE  SECOND  DENTITION 
1.  Eruption  of  the  Permanent  Teeth. — Prior 
to  its  eruption,  eacli  permanent  tooth  lies  in 
its  crypt,  which  is  complete,  except  for  the 
orifice  through  which  it  eventually  emerges. 
As  in  the  case  of  its  predecessor,  the  portion 
of  bone  over  the  crown  of  the  tooth  becomes 
absorbed,  until  an  orifice  sufficiently  large  to 
allow  the  tooth  to  emerge  is  formed.  Now, 
as  the  width  of  the  crown  of  a  tooth  exceeds 
that  of  its  neck,  some  readjustment  is  necessary, 
in  the  form  of  a  deposit  of  bone  around  the 
periphery  of  the  socket,  or  else  the  tooth  would 
be  permanently  loo.se ;  and  it  is  after  the  crown 


29 


of  the  tooth  has  emerged  through  the  orifice 
of  its  socket,  and  before  new  bone  has  been 
deposited  around  its  neck  for  tlie  purpose  of 
its  support,  that  the  tootli  is  capable  of  some 
movement,  which  allows  it  to  assume  its  correct 
position  and  alignment  in  the  dental  arch. 
Should  the  tooth  at  this  stage  meet  with  some 
mechanical  obstruction,  such  as  a  retained 
predecessor,  it  will  be  readily  diverted  from  its 
correct  course.  The  lips  and  tongue  are  the 
chief  agents  in  guiding  the  teeth  into  their 
correct  position,  ^\hen  tliey  become  fixed  by 
deposition  of  bone.  As  the  teeth  are  erupted 
intermittently,  the  surrounding  soft  parts  can 
exert  their  influence  more  advantageously  on 
any  one  tooth. 

Dates  of  Eruption  of  the  Permanent  Teeth. 
Statistics  recording  over  50,000  examinations 
of  children,  with  the  view  of  determining  the 
dates  at  which  the  various  teeth  erupt,  have 
now  been  made,  and  these,  together  with  ob- 
servations of  individual  practitioners,  allow  a 
fair  basis  for  an  approximate  statement.  A 
few  facts  on  eruption  in  general  have  evolved 
from  this  information.  In  the  permanent, 
as  in  the  deciduous,  dentition  there  is  a  slight 
variation  within  normal  limits,  and  these  teeth, 
like  their  predecessors,  erupt  earlier  in  girls 
than  in  boys.  The  limit  of  variation  in  the 
date  of  their  eruption  is  less  in  the  first 
permanent  molars  tlian  in  the  other  teeth,  but 
this  may  be  explained  by  their  earlier  eruption, 
and,  consequently,  less  range  of  time  for 
variation. 

The  following  table  gives  sufficiently  accur- 
ately the  dates  of  eruption  of  the  permanent 
teeth—    ■ 


Teeth. 

1.  First  Molars 

2.  Central  Incisors 

3.  Lateral  Incisors 

4.  First  Premolars 

5.  vSecond  Premolars 

6.  Canines 

7.  Second  Molars 

8.  Third  Molars 


Date  of  Eruption. 

6th  vear. 

7th'   „ 

8th      „ 

9th  „ 
10th  ,, 
nth  ,, 
12th  ,, 
18th-25th  year. 


This  table  corresponds  fairly  accurately  with 
that  based  on  the  more  recent  researches  of 
James  and  Pitts  (21).  The  slight  variation 
in  the  date  of  the  eruption  of  the  teeth  given 
by  various  authors  probably  depends  upon  the 
stage  at  which  the  tooth  is  regarded  as  being 
erupted,  for  between  the  penetration  of  the  gum 
and  eruption  into  occlusion  a  year  or  more 
may  elapse. 

In  the  above  table  the  teeth  are  regarded  as 
being  erupted  when  the  gum  has  been  pene- 
trated by  the  crown  of  the  tooth.  James  and 
Pitts  draw  a  finer  distinction,  and  u.se  a  system 


of  notation  in  uhicli  llic  eruption  of  tlie  tooth 
is  recorded  in  five  stages,  the  earliest  being 
that  of  penetration  of  the  gum  and  the  last 
that  of  complete  ex^jo-sure  of  the  enamel.  In 
their  statistics  they  record  as  teeth  erupting 
those  in  which  less  than  half  of  the  crown  is 
exposed,  and  the  percentage  table  is  illustrated 
by  charts,  whicli  delineate  in  curves  the  periods 
of  erujjtion  of  the  various  teeth. 

As  a  rule  the  lower  teeth  erupt  before 
the  corresponding  upjicr  teeth,  except  the 
premolars.  James  and  Pitts  give  a  variation 
in  the  two  jaws  extending  over  a  year  for  the 
centra!  incisors,  and  nearly  two  years  for  the 
lateral  inci.sors.  From  a  clinical  point  of  view, 
the  teeth  of  the  second  dentition  frequently 
erupt  in  two  batches  or  groups.  The  first 
group,  which  includes  the  first  molars  and 
the  incisors,  erupts  between  the  sixth  and 
ninth  years,  after  which  an  interval  of  a  year 
or  two  u.sually  elapses,  followed  by  the  second 
group,  consisting  of  the  premolars,  canines 
I  and  second  molars,  which  make  their  appear- 
ance between  the  tenth  and  thirteenth  years. 
It  may  be  broadly  stated  that  the  roots  of 
these  teeth  are  complete  within  about  three 
years  of  their  eruption,  with  the  exception 
of  the  third  molars,  which  are  often  complete 
at  the  time  of  their  eruption.  The  height 
to  which  the  teeth  grow  is  partly  determined 
by  the  opposition  they  meet  with,  apart  from 
a  normal  correlation  of  growth,  which  exists 
throughout  the  body. 

The  eruption  of  the  second  dentition  is  usually 
accomplished  under  quite  favourable  conditions, 
except  the  third  lower  molars,  which  not  in- 
frequently give  rise  to  local  and  general  dis- 
turbances of  some  severity  (see  Chapter  II). 
The  reasons  for  this,  according  to  Still,  are  that 
the  second  dentition  erupts  at  a  le.ss  perilous 
age  than  the  first  dentition ;  there  is  no  great 
change  in  the  child's  diet  at  this  period ;  the 
extreme  nervous  irritabihty  of  infancy  has 
passed  away ;  and  there  is  not  the  same  liabiUty 
to  catarrh  of  mucous  membrane.  Habit  spasm 
and  acquired  enuresis,  the  onset  of  which  is 
usually  between  the  fifth  and  eighth  years  of 
life,  may  be  partly  due  to  the  increased  nervous 
irritability  depending  upon  the  eruption  of  the 
teeth.  Sir  William  Cowers  has  stated  that  the 
number  of  cases  of  epilepsy  rises  at  the  age  of 
seven,  and  Nunn  relates  cases  of  epileptic 
convulsions  arrested  by  lancing  the  gums  over 
the  teeth  of  the  second  dentition. 

2.  Development  of  the  Jaws  and  Teeth. — It 
now  I'cmains  to  trace  the  growtii  of  the  jaws 
and  teeth  during  tlie  period  of  eruption  of 
the  second  dentition,  i.  e.  between  the  sixth 
and  thirteenth  years.  The  laying  down  of 
bone  on  the  outer  surface  of  the  body  of  the 
mandible  and  on   the  posterior  surface   of   its 


30 


ascending  ramus  continues,  and  the  angle  of 
the  jaw  becomes  more  massive  and  prominent. 
The  muscles  attached  to  the  jaw,  by  exerting 
traction,  open  out  its  curvatures  and  develop 
"  bone  of  attachment  ".  The  tongue,  possess- 
ing  in  addition  independent  movement,  acts 
as  a  dilating  force  in  moulding  the  bony  and 
dental  arches.  The  jaws  are  further  developed 
by  carrying  out  the  functions  they  subserve, 
e.  g.  mastication,  deglutition,  speech,  and  re- 
spiration. The  increase  of  bone  substance  is 
produced  chiefly  from  the  enclosing  periosteum, 
in  other  words,  subperiosteal  or  parosteal 
gro\vth  as  opposed  to  interstitial  or  endosteal 
growth.  In  the  upper  jaw  a  few  other  factors 
are  instrumental  in  its  development ;  efficient 


Dii 


PMx 


Fig.  44. — Showing  the  development  of  the  maxillary 
sinus  and  its  influence  on  the  growth  of  the 
maxilla  and  on  the  position  of  the  teeth  (after 
Keith). 

i",  i^,  c,  ml,  m".  Deciduous  teeth ;  IS  1°,  C,  PM\  PM=,  MS 
M",  M',  Permanent  teeth ;  AB,  Maxillary  sinus  at 
birth  ;  PMx,  Posterior  border  of  maxilla  at  birth  ; 
AA,  Maxillary  sinus  of  adult;  PMx,  Posterior 
border  of  maxilla  in  adult ;  OA,  Opening  of  sinus 
into   nose;    Di',  Deciduous  central  incisor. 

nasal  respiration  leads  to  increased  develop- 
ment of  the  nasal  passages  and  their  communi- 
cating air  sinuses,  and  thus  of  the  bones  that 
support  these  cavities.  The  traction  of  muscles 
attached  to  its  outlying  processes,  or  those  of 
contiguous  bones,  affect  indirectly  the  growth 
of  the  body  of  the  bone. 

The  maxillary  sinus  at  this  period  extends 
behind  the  second  upper  molar.  The  floor  of  the 
sinus  not  infrequently  descends  between  the 
roots  of  the  molars,  a  condition  said  by  Cryer 
(9)  to  be  more  common  among  the  white  than 
the  coloured  races.  The  third  lower  molar  is 
directed  forwards. 

It  is  instructive  to  observe  from  a  series  of 
skulls  the  pecuhar  maimer  in  which  the  upper 
molars  travel  into  their  positions,  owing  to  the 
growth  of  the  bone,  especially  that  of  the  maxil- 
lary sinus  (see  Fig.  44).  At  first  the  crowns  of 
these  are  directed  almost  entirely  backwards, 
and  subsequently  each  tooth  describes  an  arc  of 


a  cii-cle  with  the  centre  at  the  apex  of  its  root, 
until  the  crown  of  the  tooth  is  directed  almost 
vertically  dowTiwards. 

At  the  age  of  nine  years,  the  first,  second,  and 
third  permanent  molars  of  the  upper  jaw  are 
directed  downwards,  downwards  and  back- 
wards, and  backwards,  respectively ;  so  that 
their  crowns  form  a  segment  of  a  circle  with 
the  centre  at  the  apex  of  the  second  molar. 
In  the  mandible,  at  about  the  same  period,  the 
three  permanent  molars  form  a  series  of  steps, 
and  rise  into  position  as  the  alveolar  margin 
extends  backwards  to  accommodate  them. 
Their  occlusal  surfaces  at  first  look  forwards 
and  upwards,  but  later  almost  entirely  up- 
wards.   The  maxillary  tuberosities  are  prolonged 


Fig.  45. — The  maxilla  and  mandible  at  the  ninth  year. 
The  outer  alveolar  plate  has  been  removed  to 
expose  the  crypts  of  the  permanent  teeth  and  show 
the  amount  of  root  formation.  Some  of  the 
deciduous  teeth  are  retained  beyond  their  usual 
period.  {Odonlological  Museum,  Boyal  College  of 
Surgeons  of  England. ) 

beyond  the  second  molars.  The  deciduous 
incisors  are  replaced  by  their  permanent 
successors.  The  deciduous  teeth  that  remam 
are  sUghtly  loosened,  through  absorption  of 
their  roots ;  or  their  successors  are  indicated, 
in  the  case  of  the  canines,  on  the  outer  aspect 
of  the  alveolus,  and  in  the  case  of  the  premolars, 
more  directly  beneath  their  successors,  or 
towards  the  inner  side  of  the  arch,  owing  to 
their  inward  inclination.  Root  formation  has 
commenced  in  the  second  molars,  is  well  ad- 
vanced in  the  premolars  and  the  canines,  and  is 
nearly  complete  in  the  incisors  and  first  molars 
(see  Figs.  27,  45).  The  third  molars  are 
present  in  their  crypts  and  commencing  to 
calcify :  those  of  the  maxilla  are  more  advanced 
in  this  respect  and  are  directed  backwards  and 
downwards.     The  maxillary  sinus  is  about  the 


31 


size   of   a   Brazil-nut,  and   occupies  the   entire 
capacity  of  the  bone. 

Tomes  (33)  has  shown  that  the  space  occupied 
by  the  teeth  measured  along  the  centre  of  their 
crowns  only  varies  two  millimetres  in  the  first 
and  second  dentitions,  the  measurements  beins; 


Fig.  41). — The  skull  of  an  anthropoid  ape,  showing  the 
imobliterated  suture  between  the  maxilla  and 
pre-maxilla.  (Museum  of  the  Royal  College  of 
Surgeons  of  England.) 

35  mm.  and  37  mm.  respectively,  so  that  a 
slightly  more  outward  position  or  obliquity  of 
the  teeth  would  serve  to  accommodate  the  suc- 
cessors of  the  deciduous  dentition  (see  Chaj)ter 
IV,  p.  55).  Tomes  infers  from  this  that  verj- 
Uttle  interstitial  gro^^'th  occurs  in  the  jaws  in 
man,  and  gives  as  further  evidence  the  fact 
that  the  suture  between  the  pre-maxiUa  and 
maxilla  ossifies  early,  whereas  in  the  anthropoid 
apes,  which  present  marked  prognathism,  the 
suture  is  obhterated  later  (see  Fig.  46 ;  also 
Chapter  IV,  p.  75).  The  greater  width  of  arch 
formed  by  the  permanent  teeth  is  chiefly  due 
to  their  outward  obliquity.  The  premolars 
are  the  only  permanent  teeth  to  assume  the 
vertical  position,  as  occupied  by  the  deciduous 
teeth.  The  maxillary  incisor  teeth  present,  in 
addition,  an  obliquity  causing  the  teeth  of  either 
side  to  approximate  medially ;  this  is  probably 
brought  about  by  the  development  of  the 
canines  as  they  come  into  alignment  between 
the  lateral  incisors  and  premolars.  The  reason 
that  the  premolars  are  not  disturbed  by  the 
eruption  of  the  canines  may  be  that  the  back- 
ward growth  of  the  maxillary  smus  allows  suffi- 
cient space  for  the  premolars  to  attain  their 
vertical  position. 

At  the  age  of  twelve  years,  the  second 
permanent  molars  have  emerged  from  their 
crypts  and  penetrated  the  gum,  although  not 
as  yet  in  occlusion  with  their  opponents,  thus 
completing    the   second   dentition,    except    for 


the  third  molars.  At  this  period  the  roots  of 
the  incisors  and  premolars  are  fully  formed, 
those  of  the  canines  all  but  their  apices,  and 
about  two-thirds  of  the  second  molar  roots. 
The  third  molars  are  lying  in  their  crypts,  and 
their  crowns  are  calcified  (see  Figs.  27,  47). 
Tlie  roots  of  tlie  third  molars  commence  to  form 
at  about  the  age  of  sixteen,  and  the  teeth  them- 
selves to  erupt  at  any  time  from  this  period 
to  the  age  of  twenty-five  or  onwards.  The 
maxillary  sinus  loses  its  oval  shape  and  assumes 
the  adult  pyramidal  form.  This  cavity  reaches 
its  full  development  at  the  twenty-fifth  year. 

The  above  diagram  (see  Fig.  27)  shows  the 
stage  of  development  of  the  permanent  teeth 
at  the  different  years  of  life. 

The  permanent  teeth  sometimes  show  signs 
of  absorption,  but  this  is  usually  due  to  peri- 
cemental irritation  and  inflammation  ;  and  simi- 
larly, replanted,  transplanted,  and  implanted 
teeth,  occasionally  present  like  changes.  The 
macro.scof)ical  appearances  are  entirely  dif- 
ferent from  these  of  physiological  absorption, 
as  the  surface  of  the  root  is  rough  and  irregular, 
instead  of  exhibiting  the  smooth  excavations 
seen  when  the  process  is  a  normal  one.  No 
doubt,  as  in  other  parts,  the  actual  destruction 
of  the  tissue  is  brought  about  by  phagocytes, 
some  of  which  may  be  large  multi-nucleated 


Fig.  47. — The  maxilla  and  mandible  at  about  the 
sixteenth  year.  The  outer  alveolar  plate  has  been 
removed  to  expose  the  roots  of  the  permanent 
teeth.  (Odontological  Mttseum,  Royal  College  of 
Surgeons  of  England.) 

cells.  In  those  cases  where  absorption  of  a 
permanent  tooth  is  due  to  pressure  alone,  e.  g. 
the  absorption  of  the  posterior  root  of  a  second 
lower  molar  from  impingement  of  the  third 
molar,  a  section  through  the  absorbed  portion 


32 


will  show  the  typical  Howship's  lacunae  lodging  (19) 

the  absorbent  organ.  ,,f,, 

F.  C. 

BIBLIOGRAPHY  (21) 

(1)  Battme,      Robert.      Vierteljahrssclirift.      Trans. 

ill  Monthly  Review  of  Dental  Surgery,  Vol.  1.  (22) 

(2)  Bland-Sl-tton,    Sir  John.      Trans.    Odont.    Soc, 

1882-3,  p.  157.  (23) 

(3)  Carter,   J.   T.     Proc.   Roy.   Soc.    of    Med.,  Dec. 

1907,  p.  17.     Discussion,  pp.  24-2(5.  (24) 

(4)  Caotley,  Edmund.     Diseases  of  Children,  p.  225. 

(5)  Cautley,    Edmund.      Brit.    Med.    Jour.,     1905, 

p.  555. 

(6)  Choquet,    J.     A    Case    of     Delayed     Eruption.        (25) 

Dental  Cosmos,  1906,  p.  699.  (26) 

(7)  Coleman,    A.     Manual    of    Dental   Surgery    and 

Pathology.  (27) 

(8)  Coleman,     F.      Roy.     Dent.     Hospital     Annual 

Reports,   1911.  (28) 

(9)  Cryer,    M.    H.     Internal   Anatomy   of   the   Face       (29) 

pp.  37-39.  (30) 

(10)  Cunningham,  D.  J.     Text-book  of  Anatomy,  1909. 

(11)  Fairrank.  H.  a.  T.     Brit.  Med.  Jour.,  Aug.    22,  (31) 

1908,  p.  468.  (32) 

(12)  Fawcett,  Edward.     Ossification  of  Lower  Jaw       (33) 

in  Man.     Jour,  of  Amer.  Med.  Assoc.,  Jnly-Dec.        (34) 
1905,  p.  696.  (35) 

(13)  Fischer,  G.     Microscopic  Investigation  on  Erup-       (36) 

tion   of   Permanent   Teeth   and   Resorption    of 
Deciduous.     Dental  Cosmos,  Jan.   1910,  p.   115.    i 

(14)  Geilfuss,  E.  a.     Dental  Review,  1909,  p.  27.  !    (37) 

(15)  Gibson,  A.  B.     Some  Defects,  etc.,  of  Permanent 

Teeth.     Brit.  Dent.  Jour.,   1906,  Vol.  XXVII. 

p.  49.  I    (38) 

(16)  GoODHAET   &   Still.     Diseases  of   Children,   pp.    I 

47-55  I    (39) 

(17)  Grevers.     Trans.  Odont.  Soc,  Jan.  1902-3.  [ 

(18)  Guthrie,  Leonard.     Brit.  Med.  Jour.,  Aug.  22,    ,    (40) 

1908,  p.  468.  I 


Haller.     Marshall's     Operative     Dentistry,     3rd 

ed.,  p.  61. 
Hutchison,  Robert.     Brit.  Med.  Jour.,  Sept.  9, 

1905. 
James  &  Pitts.     Some  Notes  on  the  Dates  of 

Eruption   in    4850   Children.     Proc.    Roy.    Soc. 

of  Med.  (Odont.  Sec),  March,   1912. 
James,  Warwick,  W.     Proc.  Roy.  Soc  of  Med. 

(Odont.  Sec),  May  1909,  p.  12). 
Keith.     Hutnan    Embryology     and     Morphology, 

1904,  p.  16. 
Low,    Alexander.     Tlie    Development    of    the 

Lower   Jaw    in    Man.     Proc.    Anatomical   and 

Anthropological  Society,  University  of  Aberdeen, 

1905. 
Marshall.     Operative  Dentistry,  p.  62. 
Mummery,    J.    Howard.      Trans.    Odont.    Soc, 

1892-3,  p.  157. 
Pritchard,  Urban.     Brit.  Med.  Jour.,  Sept.  9, 

1905. 
ScHAEFFER.     Amcr.  Jour,  of  Anat.,  1910,  p.  318. 
Spratling.     Dental  Digest,  1905,  p.  699. 
Still,  G.  F.     Common  Disorders  and  Diseases  of 

Childhood. 
Symington  &  Rankin.     Atlas  of  Sf:iagrams,  1908. 
Tomes.     Dental  Anatomy,  1904.  p.  201. 


Tomes.      Trans.  Odont.  Soc,  1891- 


143. 


Tomes  &  Nowell.  Dental  Surgery,  1906,  p.  35. 
Trewby,  H.  W.  Roy.  Soc  of  Med.,  April  1908. 
Turner,   C.    R.     Transition   from   Deciduous   to 

Permanent  Dentition.     Dental  Cosmos,  1908,  p. 

212. 
Turner,    J.    G.     Teeth    of    Microcephalics    and 

Cretins.       Trans.     Odont.     Soc,     1901-2,     Vol. 

XXXIV,  p.  1. 
Turner,  J.  G.     Brit.  Med.  Jour.,  Aug.  22,  1908, 

p.  468. 
West.     Lectures  on  the  Diseases  of  Infancy  and 

Childhood. 
Wills,   T.   E.     Deficient   Dentition.     Brit.  Dent. 

Jour.,  April  1,  1911,  p.  380. 


CHAPTER  ir 


SERIOUS   AFFECTIONS   ASSOCIATED   WITH  THE   THIRD 

MANDIBULAR   MOLAR 


Inflammatory  processes  connected  with  the 
Third  Mandibidar  Molar  not  infrequently  lead 
to  serious  complications,  a  sequel  that  is  rare 
in  connection  with  other  teeth. 

The  explanation  of  the  occurrence  of  the 
complications  is  dependent  upon  several  factors, 
which  need  consideration.  The  molar  is 
practically  always  imperfectly  erupted;  the 
nature  of  the  tissue  in  which  the  infection 
commences  is  of  great  significance ;  but  of  chief 
importance  of  all  are  the  anatomical  relations 
of  the  tooth,  for  besides  explaining  why  the 
serious  affections  can  occur  they  partly  account 
for  the  two  factors  just  mentioned. 

Anatomical  Relations. — The  third  mandibular 
molar  is  situated  at  the  back  of  the  oral  cavity, 
quite  near  to  the  commencement  of  the  pharynx. 
In  well-developed  jaws  the  tooth  is  implanted 
in  a  manner  similar  to  the  other  teeth,  having 
an  alveolar  process  that  is  more  or  less  sub- 
servient to  it.  Where  the  space  behind  the 
second  molar  is  insufficient  for  it  to  take  up  its 
correct  position  in  the  dental  arch,  the  tooth  is 
situated  almost  entirely  in  the  body  of  the  bone. 
The  coronoid  process  lies  behind  and  to  the 
outer  side ;  but  in  cases  of  imperfect  eruption 
the  tooth  may  be  partly  covered  by  it. 

The  mucous  membrane  or  muco-periosteum 
changes  in  character  in  the  region  of  the  third 
molar  as  it  passes  backwards  from  the  dense 
gum,  which  is  firmly  bound  down  to  the  bone, 
to  the  lax  and  loosely  attached  tissue  behind  the 
tooth,  the  latter  tissue  much  more  closely 
lesembling  the  mucous  membrane  of  the 
pharynx,  with  which  it  is  continuous.  The 
degree  of  eruption  of  the  tooth  more  or  less 
determines  whether  the  surrounding  muco- 
periosteum  is  mainly  of  the  former  or  latter 
type.  The  attachment  of  the  muco-periosteum 
to  the  neck  of  the  tooth  is  usually  very  firm,  and 
\\ider  than  is  the  case  with  other  teeth. 

The  muscles  and  fasciae  in  the  neighbourhood 
of  the  tooth  affect  the  spread  of  inflammation, 
and  therefore  need  some  description. 

The  mylo-hyoid  has  attachment  to  the  internal 
oblique  line,  below  the  level  of  the  tooth  and  on 
the  inner  side  of  the  body  of  the  mandible. 
Immediately  to  the  outer  side  of  and  behind 
the  tooth  is  the  sheet  of  muscle  formed  by  the 
buccinator,  which  is  attached  quite  close  to  the 
tooth,    and    the   superior   constrictor   muscles; 


this  layer  is  strengthened  by  the  bucco-pharyn- 
geal  fascia,  and  is  covered  by  the  mucous 
membrane  of  the  cheek  and  pharynx,  the  palato- 
glossus and  palato-pharyngeus  alone  intervening 
(forming  respectively  the  glosso- palatine  and 
pharyngo-palatine  arches  of  the  fauces).  Separ- 
ating this  layer  from  the  coronoid  process  and  the 
insertion  of  the  temporal  muscle  is  a  variable 
quantity  of  loose  connective  tissue  containing  fat, 
which  is  continuous  with  the  connective  tissue  of 
the  pterygoid  region.  The  masseter  is  situated 
on  the  external  aspect  of  the  ramus  and  coronoid 
process  of  the  mandible ;  the  anterior  part  of 
the  muscle  is  separated  from  the  buccinator  by 
the  buccal  fatty  body,  which  is  continuous 
behind  with  the  fatty  connective  tissue  described 
above. 

The  attachments  and  arrangements  of  the 
deep  cervical  fascia  cannot  be  described  fuUy, 
although  important.  The  most  superficial 
layer  has  attachments  to  the  lower  border  of  the 
mandible,  to  the  zygoma,  and  to  the  hyoid 
bone ;  and  a  deep  septum  at  the  side  of  the 
pharynx  encloses  the  internal  carotid  artery, 
the  jugular  vein,  and  the  vagus  nerve,  and  is 
connected  to  the  bucco-pharyngeal  fascia. 

The  vessels  and  nerves  run  more  or  less 
together.  The  veins  are  of  chief  importance, 
as  phlebitis  with  septic  thrombosis  is  apt  to 
result  from  extensive  inflammatory  processes. 
The  plexus  of  veins  (pterygoid  plexus)  associated 
particularly  with  the  external  pterygoid  muscle, 
is  formed  by  the  veins  that  correspond  to  the 
branches  of  the  internal  maxillary  artery. 
This  plexus  has  communications  passing  to  the 
interior  of  the  cranium — to  the  cavernous  sinus 
in  particular  (veins  passing  through  the  foramen 
of  Vesalius,  tlie  foramen  ovale,  and  the  foramen 
spinosum,  as  the  middle  meningeal  veias). 
Communications  also  pass  between  this  plexus 
and  the  ophthalmic  vein  (through  the  inferior 
orl)ital  fissure),  the  pharyngeal  plexus,  and  the 
facial  vein  (deep  facial  vein). 

The  inferior  alveolar  vessels  and  nerve  lie 
in  the  mandibular  canal  immediately  below  the 
tooth,  and  are  sometimes  so  close  to  it  as  to 
cause  the  root  to  be  grooved ;  in  one  recorded 
case  the  root  of  the  tooth  possessed  a  hole, 
through  which  it  was  believed  that  the  nerve 
pas.sed. 

The  lingual  nerve  lies  between  the  mucous 


33 


34 


membrane  and  the  bone  below  the  imier  side 
of  the  third  molar.  The  long  buccal  nerve 
reaches  the  outer  surface  of  the  buccinator 
muscle  beneath  the  insertion  of  the  temporal 
muscle  into  the  coronoid  process. 

The  State  of  Eruption  of  the  Tooth.— The  third 
mandibular  molar  may  erupt  and  take  up  its 
position  in  the  jaw  in  a  manner  similar  to  the 
teeth  anterior  to  it ;  in  such  cases  the  jaws  are 
usually  well  developed,  and  sufficient  space  is 
present  behind  the  second  molar  to  allow  this 
to  occur.  In  a  large  number  of  cases  the  space 
is  inadequate,  and  the  tooth  may  present  very 
variable  degrees  in  the  stages  of  eruption  and 
may  be  situated  abnormally.  The  tooth  is 
perhaps  most  commonly  quite  free  of  the  muco- 
periosteum  on  its  anterior  and  lingual  aspects, 
whilst  buccally  and  posteriorly  its  sides  are  still 
partially  covered ;  or  the  concLition  may  be  more 
marked,  the  muco-periosteum  then  covering 
the  back  part  of  the  tooth  ;  at  times  the  antero- 
internal  cusp  only  is  showing ;  occasionally 
the  gum  will  be  full  although  it  is  not  perforated 
by  the  tooth.  Abnormal  positions  are  asso- 
ciated with  imperfect  eruption ;  the  one  most 
frequently  seen  is  where  the  tooth  is  tipped 
forwards ;  in  some  cases  this  may  occur  to  such 
a  degree  that  the  tooth  is  horizontal,  and  the 
occlusal  surface  is  in  contact  with  the  distal 
surface  of  the  second  molar.  The  crown  of  the 
tooth  is  at  times  tipped  inwards,  and  this  may 
be  so  marked  that  the  buccal  surface  is  directed 
upwards. 

Where  the  space  behind  the  second  molar 
is  markedly  insufficient,  the  third  molar  may  be 
partly  situated  beneath  the  bone  of  the  coronoid 
process.  Great  variations  in  position  also 
occur,  but  can  be  dealt  with  only  upon  their 
inchvidual  merits.  If  markedly  displaced,  the 
tooth  is  usually  to  be  found  in  the  region  of  the 
ramus  of  the  jaw  ;  in  one  case  it  reached  as  high 
as  the  neck  of  the  bone. 

The  proportion  of  fully  erupted  third  mandi- 
bular molars  to  those  imperfectly  erupted  could 
not  easily  be  stated,  as  a  definition  of  either 
condition  would  only  be  arbitrary.  It  is  certain 
that  this  tooth  is,  of  all  the  teeth,  by  far  the 
most  often  imperfectly  erupted,  and  that  a 
large  number  never  arrive  at  a  condition  of 
complete  eruption.  The  explanation  usually 
made  is  the  one  that  Salter  gave  many  years 
ago  :  "  The  difficulty  which  most  commonly 
occurs  with  the  inferior  dentes  sapientiae  is 
attributable  to  the  comparative  shortness  of 
the  horizontal  ramus  of  the  jaw.  The  tooth 
usually  grows  in  the  right  direction  and  position 
as  regards  its  neighbour  in  front,  but  from  the 
imperfect  lengthening  of  the  jaw  backwards  the 
birth  of  the  crown  is  only  partial  and  incom- 
plete." This  is,  of  course,  an  expression  in  words 
of  what  occurs,  but  it  does  not  explain  the  reason 


for  either  the  deficiency  of  space,  or  the  teeth 
being  larger  than  the  area  they  should  occupy. 

The  Mode  of  Infection. — Infection  occurs  in 
the  soft  tissues  surrounding  the  cro^vn  of  the 
tooth.  It  occurs  in  one  of  two  ways,  or  both 
may  be  factors. 

The  crown  of  a  tooth  prior  to  its  eruption  is 
covered  by  soft  tissues,  which  are  attached  to 
its  neck,  but  only  lie  in  contact  with  the 
enamel-covered  portion.  In  the  case  of  the 
third  molar  that  remains  imperfectly  erupted, 
a  pouch  therefore  exists ;  particles  of  food  and 
debris  pass  into  the  pouch,  undergo  decomposi- 
tion, and  cause  ulceration  and  infection  of  the 
cap  of  surrounding  soft  tissue. 

The  other  mode  of  infection  occurs  as  the 
result  of  ulceration  following  injury  by  the 
third  maxillary  molar  of  the  soft  tissues  over- 
lying the  mandibular  tooth.  These  tissues  are 
not  infrequently  marked  by  a  depression  or 
by  scars,  corresponding  with  the  point  of 
contact  of  a  cusp  of  the  maxillary  molar — the 
third  mandibular  molar  need  not  necessarily 
have  perforated  the  gum  tissue.  The  repeated 
irritation,  with  ulceration,  eventually  leads  to 
a  more  extensive  infection. 

The  severity  of  the  inflammatory  process  will 
depend  upon  several  factors  :  the  nature  of  the 
organism  and  the  resistance  of  the  individual : 
the  possibihty  of  free  drainage ;  and  the  char- 
acter of  the  tissues  and  area  involved. 

Dental  caries  very  rarely  plays  a  part  in  the 
infection  of  these  cases  ;  the  tooth  may  present 
anatomical  variations,  but  it  is  usually  unaffected 
by  caries,  at  least  to  the  extent  of  involving 
the  pulp-cavity. 

Symptoms  of  Infection. — In  the  earliest  stages 
there  may  be  little  more  than  discomfort,  the 
absence  of  severe  pain  being  a  common  char- 
acteristic. The  pain  or  discomfort  differs  from 
that  of  an  inflamed  pulp  or  an  acute  periodont- 
itis ;  it  is  more  or  less  constant  in  character 
and  might  be  described  as  soreness  rather  than 
an  ache.  It  is  less  disturbing  locally  than  in 
either  of  the  cases  just  mentioned,  but  the 
condition  may  render  the  patient  incapable  of 
carrying  out  the  ordinary  duties  of  life,  on 
account  of  the  general  disturbance  that  super- 
venes, the  patient  frequently  feeling  quite  ill. 

A  history  can  usually  be  obtained  of  irregular 
attacks  repeated  at  variable  intervals. 

The  extension  of  the  inflammation  from  the 
region  of  the  tooth  to  the  fauces  gives  rise  to  a 
symptom  that  is  often  treated  as  "  sore  throat  ", 
the  true  cause  not  being  recognized ;  and  in 
the  same  way  suppuration  may  be  treated  as 
quinsy.  Irritation  of  the  inflamed  tissue  by 
the  opposing  maxillary  molar  may  cause  acute 
pain,  and  may  be  a  factor  in  increasing  the 
inflammatory  process. 

On    examination,    the    tissue    overlying    the 


35 


tooth  and  that  with  which  it  is  immediately 
comiected  is  seen  to  be  red  and  swollen ;  if 
suppuration  is  established,  pus  will  be  seen  to  be 
oozing  from  between  the  soft  tissues  and  the 
tooth.  Ulceration  or  scars  from  previous 
ulceration,  or  merely  depressions  in  the  surface 
of  the  tissue,  may  be  seen,  having  been  caused 
by  contact  with  the  third  maxillary  molar. 

The  inflammation  is  usually  more  extensive 
if  the  flap  of  overlying  tissue  is  thick,  and  there 
may  be  an  ulcerated  margin ;  if  thin  it  is  more 
likely  to  slough  and  undergo  spontaneous  cure, 
small  tags  of  tissue  remaining.  The  position 
of  the  flap  on  the  inner  or  outer  side  of  the 
tooth  will  often  determine  the  direction  of  the 
extension  of  inflammation.  The  part  is  usually 
so  tender  that  digital  examination  is  practi- 
cally impossible,  and  the  mastication  and  swal- 
lowing of  food  are  rendered  very  difficult.  The 
mouth  becomes  foul,  particularly  in  the  neigh- 
bourhood of  the  tooth,  as  neither  the  normal 
cleansing  by  use,  nor  artificial  cleansing,  can 
be  carried  out.  The  tooth,  examined  by  means 
of  an  instrument  placed  upon  it,  may  be  found 
to  be  firmly  implanted,  although  frequently 
loosened  when  suppuration  is  established.  As 
the  inflammation  tends  to  proceed  backwards, 
the  second  molar  is  usually  firm,  and  although 
tender  to  pressure  is  rarely  involved  beyond  this 
extent.  When  the  tooth  is  deeply  situated, 
suppuration  may  occur  between  the  tooth  and 
the  cap  of  tissue  covering  it,  and  the  pus  may 
be  contained  in  the  small  cystic  cavity  occasion- 
ally found  over  an  erupting  tooth,  the  condition 
really  resembling  suppuration  in  a  small  denti- 
gerous  cyst. 

With  extension  of  inflammation,  the  fauces 
may  be  affected  on  the  same  side  as  the  tooth  ; 
or  the  tissues  on  the  outer  side  may  be  involved 
and  the  typical  condition  of  trismus  established. 
Many  views  have  been  expressed  upon  the  cause 
of  trismus,  some  holding  that  it  is  due  to  exten- 
sion of  the  inflammation  to  the  muscles,  others 
that  it  is  a  reflex  action  through  the  nervous 
system  (see  Chapter  XLIX) .  The  former  condi- 
tion appears  to  be  the  more  important  factor,  for 
general  anaesthesia  does  not  produce  relaxation, 
and  the  trismus  persists  for  a  long  time  after 
the  removal  of  the  tooth ;  in  one  case  the 
limitation  of  movement  was  present  for  more 
than  three  months  after  the  removal  of  the 
tooth,  although  apart  from  this  all  discomfort 
had  disappeared  completely  after  about  a  week. 
In  a  recorded  case,  after  twenty-four  j'ears  of 
Buffering  the  third  molar  was  removed,  and  there 
was  still  considerable  thickening  four  or  five 
years  afterwards.  Tomes,  in  support  of  the 
reflex  view,  quotes  a  case  where  chronic  spasm 
of  the  muscles  opening  the  jaws  was  induced. 

In  the  production  of  trismus,  it  is  possible 
that  more  than  one  muscle  may  be  involved. 


The  masseter  usually  has  been  referred  to  as 
the  chief  factor,  but  upon  what  evidence  it  is 
difficult  to  say.  It  is  true  the  tissues  external 
to  the  masseter  are  often  oedematous,  and  as  the 
muscle  is  superficial  and  most  obvious,  this  may 
account  for  the  statement  that  has  been  so 
often  repeated.  What  e\idence  exists  would 
go  to  show  that  the  temporal  muscle  was  the 
one  mainly  involved,  for  in  two  or  three  fatal 
cases,  at  the  post-mortem  examination  this 
muscle  has  been  found  to  be  severely  aft'ected, 
showing  extensive  destruction  of  its  tissue  with 
a  quantity  of  very  foul  pus.  In  a  recent  case 
of  wide  extension  of  the  infection,  with  severe 
general  toxic  effects,  no  relief  was  obtained  from 
numerous  incisions  extending  from  the  orbit 
to  low  in  the  neck,  until  free  drainage  of  the 
temporal  region  was  established,  this  site  for 
drainage  being  selected  on  account  of  the  infor- 
mation obtained  from  the  cases  referred  to 
above. 

When  trismus  is  present,  the  amount  of 
limitation  of  movement  is  variable ;  the  teeth 
can  usually  be  separated  with  a  certain  degree 
of  force  sufficiently  to  allow  the  tip  of  the  finger 
to  be  placed  between  them.  Examination 
from  the  Ungual  aspect  is  practically  impossible, 
but  occasionally  a  mirror  can  be  passed  between 
the  teeth.  By  withdrawing  the  cheek  pus  may 
be  seen  oozing  from  the  region  of  the  tooth. 

The  breath  is  usually  very  foul,  and  the 
general  condition  of  the  patient  much  reduced. 

Externally  the  swelling  is  not  very  marked, 
it  may  be  considerable,  but  usually  amounts  to 
an  obliteration  of  the  outline  of  the  mandible 
in  the  region  of  the  angle ;  the  hollow  in  the 
neck  below  may  be  filled  out,  and  the  oedema 
marked  over  the  parotid  area  both  behind 
and  over  the  jaw.  Beyond  this  area  the  tem- 
poral region  and  the  neck  are  most  frequently 
involved . 

The  amount  of  pus  present  is  usually  small ; 
this  may  possibly  be  due  to  the  nature  of  the 
infecting  organism.  In  cases  where  extension 
of  the  infection  has  taken  place  to  such  a  degree 
that  external  incisions  are  necessary,  it  is 
frequently  most  difficult  to  find  a  localized 
collection  of  pus  that  can  be  regarded  as  satis- 
factory for  the  purpose  of  establishing  drainage. 

The  lymphatic  glands  in  the  neck  are  usually 
enlarged  and  tender,  and  at  times  may  be  the 
cause  of  the  patient  seeking  relief  without 
recognizing  the  primary  source  from  ■nhich 
absorption  of  toxic  products  has  taken  place. 
j  Serious  affections  following  infection  of  the 
soft  tissues  around  the  third  mandibular  molar 
are  dependent  upon  the  anatomical  relations 
of  the  tooth  ;  the  inflammation  may  be  severe 
and  localized,  but  direct  extension  to  neighbour- 
ing parts  is  more  common,  with  a  general 
toxaemia,  which  is  at  times  fatal. 


36 


Necrosis  is  not  a  common  sequel,  being  more 
frequent  perhaps  after  extraction  of  the  tooth ; 
the  muco-periosteum  may  be  stripped  up  from 
the  bone,  and  the  process  be  similar  to  a  periost- 
itis connected  with  another  tooth ;  it  is  rare, 
for  the  primary  infection  is  in  the  soft  overlying 
tissue,  and  not  in  the  bone,  as  occurs  with  an 
infection  through  the  apical  foramen  of  a  tooth. 
A  streptothrix  infection  (actinomycosis)  must 
be  borne  in  mind  if  bare  bone  remains  for  a 
long  period  without  healing. 

Suppuration  with  sloughing  of  the  tissues 
immediately  around  the  tooth  may  occur. 
Pus  may  be  discharged  into  the  mouth  or  upon 
the  skin  surface  externally  ;  the  persistence  of 
a  sinus  in  the  region  of  the  angle  of  the  mandible 
may  extend  over  a  long  period. 

Acute  neuralgia  only  occasionallj^  occurs, 
being  much  more  frequent  after  operation :  if 
present  it  is  verj'  severe  and  j^ersistent  in  type, 
and  probably  due  to  the  inflammation  extending 
to  the  inferior  alveolar  canal.  Referred  pain 
may  be  due  to  this  condition  :  Head  gives  "  the 
superior  laryngeal  area  "  ;  the  mandibular  fora- 
men is  said  to  be  a  site  to  which  pain  may  be 
referred  ;  and  the  point  of  the  shoulder  and  the 
arm  are  recorded  as  points  to  which  undoubtedly 
pain  was  referred.  The  chronic  irritation,  with 
attacks  of  more  acute  inflammation  repeated 
at  intervals,  often  causes  a  hypercementosis  of 
the  roots  of  the  tooth,  which  not  infrequently 
show  marked  thickening  (exo.9tosis). 

Much  importance  has  been  attached  to  the 
effect  of  the  third  molar  upon  the  second  one. 
Absorption  of  the  latter,  due  to  the  presence 
of  the  former,  is  constantly  stated  to  occur, 
but  it  is  exceedingly  difficult  to  find  any  cases 
where  true  absorption  has  taken  place.  In  one 
ease  a  radiograph  showed  the  third  molar, 
which  was  completely  buried,  in  contact  with 
and  apparently  causing  absorption  of  the  second 
molar;  the  patient  was  suffering  from  severe 
neuralgia,  which  was  thought  to  be  due  to 
pulp  irritation — so  severe  was  it ;  the  second 
molar  was  removed,  wth  complete  relief  to  the 
patient ;  the  position  of  contact  of  the  third 
molar  was  definitely  noticeable,  but  true  ab- 
sorption could  not  be  said  to  have  occurred. 
It  might  be  stated  that  absorption  of  the  second 
molar  from  the  presence  of  a  third  molar  does 
■occur,  but  is  very  rare. 

Wlien  the  third  molar  has  perforated  the  gum 
and  is  in  contact  with  the  second  molar,  caries 
is  quite  commonly  induced  in  the  posterior 
surface  of  the  second  molar  at  its  neck,  and 
occasionally  in  the  third  molar  as  well;  the 
movement  forwards  and  upwards  of  the  third 
molar  into  the  cavity  of  the  second  is  a  common 
sequence. 

The  foul  condition  of  the  mouth  associated 
with  trouble  in  connection  with  this  tooth  will  | 


sometimes  cause  extensive  ulceration  of  the 
mucous  membrane  of  the  cheek,  probably  due 
primarily  to  a  slight  abrasion. 

Extension  of  the  inflammation  may  take  jjlace 
beneath  the  muco-periosteum  on  the  inner  side 
of  the  tooth,  involving  the  floor  of  the  mouth; 
in  this  position  pus  may  be  discharged  spon- 
taneously, or  an  incision  may  be  necessary. 
The  process  may  extend  downwards  beneath 
the  cervical  fascia,  causing  a  swelling  beneath 
the  jaw  and  above  the  hyoid  bone  ;  the  condition 
may  be  very  serious,  as  the  pus  does  not  easily 
escape ;  the  resulting  toxaemia,  with  perhaps 
oedema  of  the  glottis,  has  been  kno\\'n  to  proceed 
to  a  fatal  issue. 

In  cases  where  extension  has  taken  place 
towards  the  pharynx,  pus  has  been  discharged 
into  the  pharynx,  and  in  one  case  into  the  retro- 
pharyngeal tissue,  causing  a  pre-vertebral 
abscess.  In  another  case  suppuration  involved 
the  internal  carotid  ai'tery,  the  softening  leading 
to  rupture  and  fatal  haemorrhage. 

Externally  the  suppurative  process  may  extend 
into  the  neck.  It  may  strip  up  the  periosteum ; 
and  the  cervical  fascia,  blending  with  this  tissue 
at  the  lower  border  of  the  mandible,  may  deter- 
mine the  extension,  so  that  a  condition  similar 
to  that  described  above  may  be  produced. 
More  cases,  however,  are  recorded  of  the  exten- 
sion occurring  beneath  the  j)latysma  and  external 
to  the  cervical  fascia,  and  suppuration  may 
extend  as  far  as  the  clavicle  ;  in  one  case  sinuses 
were  established  just  below  the  clavicle. 

Extension  of  the  loose  fatty  connective  tissue 
outside  the  bucco-pharyngeal  muscular  (bucci- 
nator and  superior  constrictor  muscles)  and 
fascial  layer  forms  perhaps  one  of  the  common- 
est sites  of  secondary  infection.  The  temporal 
muscle  at  its  insertion  is  directly  involved,  and 
the  structures  situated  in  the  pterygoid  region 
may  be  included  in  the  process,  the  most 
important  of  these  being  apparently  the  veins. 
Following  phlebitis,  septic  thrombosis  may  be 
established,  and  if  extension  occurs  through  the 
veins  to  the  interior  of  the  cranium  most  serious 
results  will  follow.  Several  cases  are  on  record 
of  septic  thrombosis  of  the  cavernous  sinus, 
where  the  septic  thrombus  was  traced  through 
the  communicating  veins  from  the  sinus  to  the 
pterygoid  plexus. 

Cases  of  meningitis  and  of  cerebral  abscess 
are  recorded,  although  they  are  not  uncompli- 
cated. Multiple  abscesses  in  the  masseter  and 
sterno-mastoid  occurred  in  one  case,  but  pyaemia 
has  been  the  fatal  termination  in  several  of  the 
cases  recorded.  Other  fatal  cases  are  described 
as  due  to  septicaemia. 

It  has  been  stated  that  necrosis  of  the  mandible 
is  uncommon,  but  at  the  post-mortem  of  fatal 
cases  the  periosteum  has  been  found  to  be 
stripped  up  extensively,  and  in  one  case  acute 


37 


osteomyelitis  of  the  mandible  was  present, 
and  was  possibly  tlie  first  stage  of  the  fatal 
septicaemia. 

Treatment. — Treatment  in  all  cases  consists 
in  removal  of  the  tooth  and  surgical  procedure 
dealing  with  the  particular  comphcation. 

Removal  of  the  second  molar  has  been  advo- 
cated, but  is  inferior  to  removal  of  the  offending 
tooth ;  the  third  molar  then  occasionally  takes 
up  more  or  less  the  position  of  the  second 
molar  in  the  arch,  but  more  commonly,  if 
the  case  is  at  all  severe,  the  removal  of  the 
third  molar  is  necessary  as  well  as  the  second. 
The  second  molar  should  be  extracted  only  in 
those  cases  in  which  the  third  cannot  otherwise 
be  removed. 

After  extraction  of  the  offending  tooth, 
drainage  of  the  socket  must  be  maintained,  and 
is  best  achieved  by  frequent  irrigation:  the 
position  of  the  tooth  is  most  unfavourable  for 
drainage,  and  unless  care  is  taken  serious  sequelae 
may  result.  Acute  neuralgia  is  frequent  im- 
mediately after  extraction,  and  subsequently; 
a  saturated  solution  of  chloroform  in  hot  water 
held  in  the  mouth  will  give  temporary  relief, 
but  s\Tinging  out  the  socket  is  the  most  impor- 
tant factor  in  treatment 

During  the  early  stages,  prior  to  removal  of 
the  tooth,  an  incision  may  be  made  dividing  the 
muco-periosteum  down  to  the  bone  on  the  outer 
side  of  the  tooth  ;  in  some  cases  the  flap  of 
gum  overhang  the  tooth  may  be  removed  with 
advantage ;  extraction  of  the  third  maxillary 
molar  is  jirobably  the  most  useful  of  the  measures 
that  are  perhaps  merely  palliative. 

It  is  unnecessary  to  discuss  the  more  serious 
forms  of  treatment,  as  the  patient  will  be  in  the 
hands  of  a  surgeon,  but  it  may  be  of  use  to 
recall  the  imi^ortant  fact  that  the  pterygoid 
region  is  the  part  most  frequently  affected  \\  hen 
a  localized  area  of  supjJuration  camiot  be  found. 
In  cases  of  acute  neuralgia,  possible  exposure 
of  the  pulp  in  the  second  molar  must  be  remem- 
bered ;  the  cavity  is  often  very  low  down  at  the 
neck  of  the  tooth  and  may  be  difficult  to  find 
(see  Chapter  XLVII).  Practure  of  the  second 
molar  may  occur  during  the  operation,  and 
must  not  be  forgotten  as  a  possible  cause  of 
after-pain. 

During  extraction  of  the  tooth  local  injury 
to  the  parts  may  be  severe.  The  commonest 
is  perhaps  the  stripping  up  of  the  muco- 
periosteum  from  the  bone,  the  attachment  of 
this  tissue  being  very  firm  at  the  neck  of  the 
tooth.  In  one  recorded  case  haemorrhage 
occurred,  and  plugging  the  socket  prevented  the 


blood  passing  into  the  mouth,  but  it  continued 
into  the  connective  tissue  of  the  neck  beneath 
the  platysma,  extending  as  far  as  the  clavicle. 
In  another  case  the  tooth  was  lost  at  the  opera- 
tion and  not  discovered  until  later ;  it  had 
been  forced  between  the  muco-periosteum  and 
the  bone,  being  sub.sequently  found  near  the 
lower  and  inner  margin  of  the  mandible.  A 
case  is  recorded  in  wliich  the  mandible  was 
fractured.  W.  W.  J. 


BIBLIOGRAPHY 

(1)  Badcock,   0.   H.     Fracture   of  Mandible   during 

attempted  extraction  of  a  Third  Molar.      Trans. 
Odont.  Soc,  1902-3.     Vol.  XXXV,  p.  229. 

(2)  Baker,  A.  A.  VV.     Brit.  Mid.  .Jour.,  Nov.  1907. 

(3)  Canton,  E.      Trans.   Odont.  Soc,    1879-80.     Vol. 

XII. 

(4)  Canton,  F.  Ab.sorption  of   Second   Molar  due  to 

pressure   of  impacted   Wisdom  Tooth.      Trans. 
Odont.  Soc,  1882-3.     Vol.  XV,  p.  189. 

(5)  Coleman,  A.     (A  case  with  a  history  of  twenty- 

four  years.)     Trans.  Odont.  Soc,  1875-6.     Vol. 
VIII,  p.  225. 

(6)  Eve,  Sir  Frederic.   Trans.   Odont.   Soc,  1887-8. 

Vol.  XX,  pp.  232  et  seq. 

(7)  Gould,  Sir  Alfred  Pearce.     Medical  Society  of 

London,  March,  1886. 

(8)  Heath,  Christopher.     Diseases  and  Injuries  of 

the  Jaws. 

(9)  Howard,   G.   T.      Inter-colonial  Medical  Journal 

of  Australasia,  .July,  1899. 

(10)  James,  W.  W.     Extravasation  of  Blood  into  the 

tissues  of  the  neck.     Trans.  Odont.  Soc,  1906-7. 
Vol.  XXXIX,  p.  104. 

(11)  James,     W.    W.     Some     Surgical    Complications 

associated  with  the   Third   Mandibular  Molar. 
Royal  Dental  Hospital  Gazette,  Dec,  1910. 

(12)  Moon,    H.     Epilepsy   and   Third   Molar.      Trans. 

Odont.  Soc,  1881-2.     Vol.  XIV,  p.  101. 

(13)  Mummery,  J.   R.     Trans.   Odont.  Soc,    1879-80, 

Vol.  XII,  p.  255. 

(14)  Mummery,  J.  H.     Unerupted  Wisdom  Tooth  and 

Deafness.      Trans.    Odont.    Soc,    1900-1.     Vol. 
XXXIII,  p.  164. 

(15)  Pollock,    G.    D.     Trans.    Odont.    Soc,    1875-6. 

Vol.  VIII,  p.  16. 

(16)  Roughton,     E.      Trans.     Odont.     Soc,     1901-2. 

Vol.  XXXIV,  p.  40. 

(17)  Salter.     Dental  Pathology  and  Surgery,  p.  236. 

(18)  Sercombe.      Trans.  Odont.  Soc,  1857-8.     Vol.  II 

(old  series),  p.  53. 

(19)  Sewill,     H.     Paralysis     after    extraction     of     a 

Wisdom    Tooth.      Trans.  Odont.  Soc.     1880-1. 
Vol.  XIII,  p.  110. 

(20)  Taylor,   Gordon.     A  Case  of  Infection  of  the 

Cavernous    Sinus    due    to    Oral    Sepsis.     Proc. 
Hoi/.  Soc  of  Med.  {Odont.  Soc).  1911. 

(21)  Tomes,  C.  S.     Dental  Sunjery,  4th  ed.,  pp.   408 

et  seq. 

(22)  Walker,   Joseph.     Paralysis  of  Inferior   Dental 

Nerve    following    extraction    of    Third    Molars 
Trans.  Odont.  Soc,  1883-4.     Vol.  XVI,  p.  68. 

(23)  Weiss,     Felix.     Trans.     Odont.     Soc,     1875-6. 

Vol.  VIII,  p.  211. 


CHAPTER    IIP 

ABNORMALITIES    OF    SIZE,   NUMBER,    FORM,    AND    STRUCTURE 


ABNORMALITIES    OF   THE 
TEETH 


PERMANENT 


SIZE. — There  is  considerable  variation  in  the 
size  of  permanent  teeth  (Fig.  4S)  ;  this  con- 
dition may  be  conveniently  divided  into  three 
varieties — 


8    9^ 


and  small  stunted  individuals  are  usually  found 
to  have  small  teeth,  but  the  reverse  may  be 
met  with  in  the  occurrence  of  a  dentition 
of  very  large  teeth  in  a  very  undeveloped 
individual.  The  condition  of  general  dental 
maldevelopment  met  mth  in  cretins  must  be 
excluded  from  this  rule,  as  it  has  been  shown 


A 


Fig.  48. 


that  the  normal  conditions  may  be  nearly 
api^roached  by  the  employment  in  early 
years  of  suitable  remedies  for  the  general 
disorder. 

NUMBER. — It  is  more  common  to  find  more 
teeth  than  normal  (supernumerary  and  supple- 


(1)  Cases  where  individual  teeth,   being  too 

large  or  too  small,  are  out  of  harmony 
with   their  fellows. 

(2)  Cases  where  the  dentition  as  a  whole  is 

composed  of  teeth  larger  or  smaller 
than  normal. 

(3)  Cases  where  the  dentition  is  too  large  or 

too  small  compared  with  the  condition 
expected  of  an  individual  of  that  stature 
and  development. 

(1)  While  no  two  teeth  are  exactly  alike, 
individual  teeth  (22)  (32)  tend  to  vary  in  a 
particular  direction.  The  maxillary  centrals 
(Fig.  49)  and  canines  (27)  (4-4)  tend  to  be  larger, 
the  laterals  smaller,  than  normal.  Mandibular 
second  premolars  tend  to  be  larger,  maxillary 
third  molars  smaller,  and  mandibular  third 
molars  larger,  than  normal. 

(2)  Cases  where  the  dentition  is  composed  as 
a  whole  of  teeth  larger  than  normal  are  more 
common  than  the  opposite  condition.  A  con- 
dition of  large  teeth  crowded  in  the  arch  is  more 
common  than  small  teeth  spaced. 

(3)  Tall,  well-developed  individuals  may  usu- 
ally be  expected  to  have  large  teeth  (Fig.  50a), 

'  The  drawings  to   illustrate?  this  chapter  were  made  from  specimens  in  the  Museum  of  the  Royal  Dental 
Hospital  of  London  by  Mr.  W.  H.  Dye. 

38 


Fig.  49. 

mental  teeth)  than  a  reduction  in  number. 
Cases  of  total  absence  of  both  dentitions  (69) 
(72)  and  of  the  permanent  dentition  only  have 
been  recorded  (33)  (50).  The  condition  may 
be  observed  in  one  jaw  only  (maxilla),  and 
limited  to  one  side  (2)  (43a).     These  conditions 


39 


are    often     associated   with    other    congenital     eruption.     When  a  permanent  maxillary  camne 
.  .  It,  .iiicoinrr    a  rn rlinaranli  will  nracticallv  alwavs 


defects. 

Absence  of   Teeth. — Absence  of  teeth  of  the 


Fig.  50a.— Model  of  the  maxillajof  a  Zulu. 


FiQ.  50b. — Model  of    the   maxilla   of  an   undeveloped 
boy  aged  14. 

permanent  dentition  is  naturally  associated  with 
the  retention  of  many  of  the  deciduous  teeth 
to  adult  age ;  in  these 
cases  the  teeth  of  the 
permanent  set  that  do 
erupt  are  usually  the  first 
molars  and  maxillary  can- 
ines, the  latter  erupting 
nearer  the  median  line 
than  usual  (18)  (38)  (49) 
(51)  (63)  (89)  (see  Fig.  51). 
Absence  of  the  second 
premolars  is  not  uncom- 
mon (25)  (40)  (93).  ,  ,  , , 
The  diagnosis  of  absence  of  teeth  should 
always  be  confirmed  by  radiographs,  for  it 
cannot  be  doubted  that  some  recorded  cases  of 
absence  of  teeth  may  have  really  been  retarded 


is  missing,  a  radiograph  will  practically  always 
show  the  tooth  to  be  present  in  the  alveolus; 
on  the  other  hand,  when  the  maxillary  laterals 
do  not  erupt  they  are  generally  altogether 
wanting  ;  while  in  the  case  of  failure  of  the  lower 
second  premolar  to  be  present,  with  retention  of 
the  deciduous  molar,  the  chances  are  about  equal 
that  the  second  premolar  is  present  or  absent. 
The  absence  of  teeth  may  be  due  to — 

(1)  Failure  of  the  enamel-organ  to  form  the 

requisite  tooth -germ,  or  of  the  tooth- 
germ  to  be  afterwards  properly  calcified. 

(2)  Failure  of  the  eruption  of  the  calcified 

tooth-germ. 

(3)  Injury  to  developing  tooth,  from  trauma, 

sepsis,  or  necrosis  of  bone. 

(4)  Dislocation    of    the    tooth-folhcle    of    a 

premolar  during  extraction  of  the 
deciduous  predecessor;  the  develop- 
ing premolar  behig  closely  enveloped 
by  the  roots  of  the  deciduous  molar. 

(5)  Transformation  of  the  tooth-germ  into  an 

odontome. 

(6)  Coincidence  of  a  congenital  cleft  with  a 

tooth-follicle. 

Absence  of  the  central  incisors  occurs  in  the 
mandible  (2)  (13a)  (20)  (23),  and  as  a  very  rare 
condition  in  the  maxiUa  (55).  Absence  ot 
maxillary  laterals  is  the  most  common  condi- 
tion after  absence  of  the  third  molars  (92). 

Absence  of  the  canines  is  practically  unkno\vn ; 
a  radiograph  always  shows  the  tooth  to  be 
present  in  the  alveolus. 

Of  the  premolars  the  second  mandibular  is 
most  commonly  absent. 

Absence  of  the  third  molar  is  said  to  be 
very  common;  this  statement  is  hard  to 
verify  clinically  for  the  following  reasons— 

(a)  The  difficulties  in  distinguishing  between 
the  second  and  third  molars  in  the 
maxilla. 


Fig.  .51. 


(b)  The    difficulty    in    obtaining    from    the 

patient   a    rehable    history    of   loss   ot 
teeth. 

(c)  The  delayed  eruption  of  these  teeth. 


40 


Radiographs  taken  for  various  dental  purposes 
often  show  unerupted  third  molars  in  elderly 
people,  the  presence  of  which  was  not  suspected. 

It  is  interesting  to  note  that  the  maxillary 
lateral  incisor  is  subject  to  the  followdng  varia- 
tions from  normal  in  order  of  frequency  : 
peg-shape  (unilateral  or  bilateral),  absence 
(unilateral  or  bilateral),  gemination,  and  sup- 
plemental. 

The  maxillary  lateral  is  commonly  absent, 
often  symmetrically  so.     A  tendency  to   this 


Fig.  52. 

suppression  is  indicated  by  the  occunence  of 
peg-shaped  and  deformed  teeth  in  this  situation. 

In  the  Chnic  of  J.  G.  Turner  at  the  Royal 
Dental  Hospital  of  London,  out  of  477  consecu- 
tive patients,  loss  by  extraction  and  caries  being 
carefully  excluded,  three  cases  of  bilateral 
absence,  and  two  cases  of  absence  on  the  right 
side,  occurred.  Ten  eases  of  bilateral  peg- 
shaped  laterals,  seven  cases  of  peg-shaped  on 
the  right  side,  and  three  cases  of  peg-shaped 
on  the  left  side,  were  noted. 

The  variation  and  suppression  of  the  maxillary 
lateral  have  been  noted  to  occur  as  an  hereditary 
condition,  appearing  in  parents  and  offspring 
(24)  (48).  In  lower  animals  with  degenerated 
dentitions  a  peg-shaped  single-rooted  tooth  may 
take  the  place  of  a  complex  molar,  e.  g.  Aard- 
wolf  (Fig.  52). 

Excess  in  Number.— Extra  teeth  usually  fall 
into  one  of  four  varieties — 

1.— (12)  (19)  (26)  (28)  (52)  (53)  (54i/)  (65)  (67) 
(68)  (70)  (74)  (81)  (86,  No.  1,  p.  8)  (88). 
Peg-shaped  teeth  (by  far  the  most 
common  variety)  (Pig. 53) ;  these 
are  found  between  or  behind  the 
maxillary    incisors,    or   behind 
tlie  second  maxillary  molars  on 
the  buccal  aspect;  rarely  in  the 
mandible,  in  tlie  molar  or  canine 
region.     One  or  two  is  the  com- 
FiG.  53.nion  number  to  be  found.     As 
many  as  twenty -eight  have  been 
recorded  (79,  p.  282).     The  size  of  these 
teeth    (45)    (79,  p.   366)    varies   from  a 
minute   denticle   to   larger  size,   never 


exceeding  the  size  of  a  normal  tooth. 
The  root  is  single  and  often  curved. 
Extraction  has  thus  often  resulted  in 
the  removal  of  neighbouring  teeth. 
-Tuberculated  teeth  (Fig.  54),  found  be- 
hind the  upper  incisors  ;  these  are  usually 


Fig.  54. 

symmetrical.  A  mandibular  tooth  of 
like  nature  in  a  similar  position  has 
been  recorded. 

3.- — Teeth  similar  to  those  of  the  second 
variety,  but  having  an  appearance  of 
one  portion  being  invaginated  into 
another  portion  of  the  tooth.  Many 
curious  shapes  are  met  ^^■ith,  and  are 
considered  by  some  authorities  to  be 
forms  of  composite  odontomes. 

4. — Resembhng  normal  teeth  in  the  arch ; 
these  teeth  are  termed  supplemental, 
and  are  found  commonly  in  the  lateral 
and  premolar  regions ;  thus  the  patient 
would  have  two  laterals  (4)  (13)  (29) 
(31)  (58)  (71)  (90),  or  three  premolars 
(10)  (30)  (62)  or  molars,  on  the  same 
side  (16). 

In  the  molar  region  the  above  described 
peg-shaped  supernumerary  is  sometimes  found 
to  be  geminated  with  one  of  the  molar  teeth 
(Fig.  55) ;  a  careful  examination  should  there- 
fore be  made  of  these  cases  before  extraction. 
By  observation  a  series  of  specimens  can  be 
found  to  sho\\  the  gradual  transition  from 
an  enamel  nodule  to  this  condition.  (Fig.  55 
(a,  b,  c,  d)).  The.se  teeth  often  cause  irregu- 
larities in  the  arch,  and  from  their  position 
may  impinge  on  the  tongue  and  hps,  causing 
alteration  in  speech.  Their  presence  causes 
caries  in  the  adjoining  teeth,  from  the  extra 
facihties  afforded  by  their  presence  for  lodge- 
ment of  food. 

FORM. — All  teeth  are  subject  to  certain 
obvious  variations — 

1.  Twisted  or  Ciu'ved  Roots  (91).  These  may 
be  due  to  movement  of  the  tooth  during  calcifi- 
cation, the  calcified  and  uncalcified  portions 
yielding  differently  to  the  force  expended  on  it, 
which  may  be  either  the  growth  of  the  jaw  or  the 
pressure  of  other  teeth  in  a  crowded  arch. 

Cases  have  been  recorded  of  a  condition  in 
which  the  teeth  presented  sharp  points  in  place 


41 


of  the  usually  flattened  cusps ;   the  incisor  teeth 
were   also   pointed,   thus  giving   the   dentition 


t"lG. 


Fig.  55a 


Fig.  55b. 


Fig.  55c. 


Fig.  55d. 


the  appearance  of  the  insectivorous  type  (6) 
(54a)  (54f)  (64).  A  less  severe  condition  is 
more  commonly  met  with,  in  which 
the  maxillary  laterals  are  pointed  cones 
and  the  molars  have  the  pointed  cusps 
noted  above.  These  teeth  are  usually 
without  the  fourth  cusp  (hypocone), 
and  would  seem  to  be  a  reversion  to 
a  primitive  type. 

2.  A    disproportion     between     the 

length  and  breadth  of  the  crown  compared  with 
the  average  normal  relationship,  and  an  exces- 
sive size  of  the  crown  compared  with 
the  root. 

3.  Elongation  of  the  root  (59). 


a  peg-shaped  supernumerary  (Fig.  56).  An 
extra  root  may  be  present  on  the  lingual  aspect. 

Lateral  Incisor. — Disproportion  of  length  of 
the  crown  and  the  root.  Development  of  the 
cingulum  on  the  lingual  aspect  of  a  well-marked 
neck.  Folded  appearance  of  the  tissues.  Peg- 
shaped  appearance  of  the  crowns.  Roots. — ■ 
Two-rooted,  following  the  same  lines  as  in  the 
centrals. 

Canine.  —  Very  little  variation.  A  well- 
marked  cingulum.  The  root,  long,  curved,  and 
finely  tapered. 

First  Premolar. — Three-cusped  crown,  the 
extra  cusp  being  between  the  two  normal  ones. 
Exaggeration  of  the  usual  reniform  shape 
shown  in  cross  section  at  the  enamel  and 
cementum  junction.  Roots. — Varieties  in  de- 
gree of  fusion  of  the  roots  up  to  complete 
fusion.  Three  separate  roots  placed  (35)  (46) 
(87)  as  in  the  molar,  the  two  buccal  roots 
usually  being  fused  together. 

Second  Premolar. — Variation  of  the  crown  is 
rare.  The  root  is  usually  single,  sometimes 
very  much  flattened,  with  a  tendency  to  division 
into  two  or  three  roots. 

First  Molar. — Extra  cusps  are  common — 

(rt)  On  lingual  aspect ;  this  distinguishes  the 
tooth  from  a  second  or  third  molar.     A  series 


Fig. 


of   teeth   can   be   easily   selected   showing   the 
different  stages  of  development  of  this  cusp, 


THE  MAXILLARY  TEETH 

Central  Incisor. — The  cutting  edge 
presents  the  primitive  cusps  more  pro- 
nounced than  usual.     Over-development  of  the 
cingulum    causes    a   grooving    on    the    lingual 


Fig.  50. 


aspect,  which  is  continued  down  to  the  root.     It 
would  appear  that  a  certain  number  of  two- 
rooted  incisors  are  formed  by  gemination  with 
2* 


from  a  small  bulge  on  the  cingulum  to  a  large 
cusp  on  the  grinding  surface  (Fig.  57). 

(6)  A  cusp  present  on  the  grinding  surface 
between  the  antero-external  and  the  internal 
cusps. 

It  is  uncommon  to  have  a  cusp  absent,  but 
various  degrees  of  development  of  the  fourth 
cusp  (hypocone)  may  be  met  with  (Fig.  58). 

First  Molar  Roots. — Fusion  is  less  common 
than  in  second  and  tliird  molars,  the  order  of 
frequency  being — 

Two  buccal  roots. 
Posterior  buccal  to  palatine. 
Anterior  buccal  to  palatine. 
All  roots  fused  (very  rare). 


42 


An  extra  root  may  be  found  between  the 
anterior  buccal  and  palatine ;  this  may  vary 
in  size  from  the  thickness  of  a  hair  to  a  root  as 
large  as  any  other  root  present  on  the  tooth. 
This  variation  is  so  common  that  it  must  be 
always  excluded  in  root-canal  treatment.  The 
extra  root  may  be  partially  joined  to  the  pala- 
tine root,  or  webbed  to  the  anterior  buccal. 

It  may  be  noted  that  the  amount  of  pulp- 
tissue  being  roughly  equal  in  all  first  molars, 
the  presence  of  a  small  palatine  root-canal 
accompanied  by  normal  buccal  roots,  or  of  any 
root  smaller  than  usual,  should  ^^■arn  the  operator 
to  be  on  the  look-out  for  extra  roots. 

Second  Molar. — The  shape  of  tlie  crown  varies, 
but  is  less  square  and  more  diagonal-shaped 
than  in  the  first  molar.  Extra  cusps  are  not 
common.  The  loss  of  the  fourth  cusp  (hypo- 
cone),  giving  the  tooth  a  triangular  shape,  is  a  j 
common  variation. 

Oblique-rooted  Second  Molar. — This  term  has 
been  introduced  by  Booth  Pearsall,  and  is  used  [ 
to  denote  a  variety  of  molars  in  which  the  roots 
are  placed  in  a  line  as  the  result  of  ; 
the  displacement  forwards  and 
p^— ^  inwards  of  the  posterior  buccal 
root  (Fig.  59).  As  this  condition  is 

Fig.  59.  often  associated  with  a  diagonal  or 
flattened  crown  its  presence  may 
sometimes  be  thus  anticipated.  These  teeth 
can  be  best  removed,  if  root-forceps  must  be 
used,  by  grasping  the  anterior  buccal  and 
palatine  roots. 

Second  Molar  Boots. — Fusion  of  the  roots  is 
more  common  than  in  the  first  molar;  the 
roots  fused  follow  that  tooth  in  their  order  of 
frequency. 

Modifications  in  the  form  of  the  roots  are  too 
numerous  and  varied  to  be  classified ;  it  is 
common  to  find  the  apical  portion  of  the  buccal 
roots  curving  outwards. 

An  extra  root  may  be  found  in  the  same 
region  as  has  been  described  above  in  the  first 
molar. 

Third  Molar. — The  variations  of  this  tooth  are 
so  complex  and  numerous  that  a  normal  tooth 
is  very  difficult  to  find,  except  among  savage 
races.  It  is  possible,  however,  to  find  in  civilized 
races  well-formed  jaws  and  dental  arches  having 
in  place  the  third  molars ;  these  teeth  when 
normal  have  crowns  shaped  like  the  second 
molars,  except  that  the  fourth  cusp  is  usually 
absent.  The  third  molar  varies  in  size  from 
a  small  peg-shaped  denticle  to  a  small  two-cusped 
tooth  (not  unlike  an  upper  premolar  tooth)  up 
to  normal,  but  never  larger.  The  roots  are 
usually  all  fused. 

The  Occurrence  of  Fused  Roots. — The  difficulty 
of  accurately  distinguishing  the  upper  molars 
from  each  other  as  isolated  specimens  is  rather 
great.     However,  an  upper  molar  tooth  ha\'ing 


an  extra  cusp  on  the  lingual  surface  may  be 
safely  taken  to  be  a  first  molar ;  the  difierence 
bet\veen  the  second  and  third  is  not  so  easily 
determined. 

A  chance  collection  of  182  molars  was  taken — 

40  of  these  had  fused  roots  (of  one  sort  or 
another) ;   and  of  these  40, 

4  were  first  molars, 
24  were  second  molars,  and 
12  were  third  molars. 

A  chance  collection  of  105  molars  with  fused 
roots  was  taken — 

11  of  them  were  first  molars  and  had  the 
posterior  buccal  and  palatine  roots 
fused ; 

53  of  them  were  second  molars,  of  which 

10  had  aU  roots  fused, 

1 1  had  the  buccal  roots  fused, 

16  had  the  posterior  buccal  fused  to  the 

palatine,  and 
16  the  anterior  buccal  to  the  palatine; 

41  were  third  molars. 

THE    MANDIBULAR    TEETH. 

Central  and  Lateral  Incisors.  — •  Very  little 
variation  in  crown  or  root  has  been  noted. 
The  condition  present  on  the  incisal  edge  when 
the  tooth  is  erupted  may  persist  much  later 
than  usual. 

Canine. — -The  crowns  vary  somewhat  in  the 
development  of  the  cingulum,  those  with  a 
large  cingulum  sometimes  looking  like  a  maxil- 
lary canine. 

Two-rooted  canines  are  very  common,  the 
two  roots  being  placed  linguaUy  and  buccaUy ; 
the  extra  root  may  be  small  in  size  or  large 
enough  to  give  an  appearance  of  bifurcation 
of  the  single  root.  The  condition  is  invariably 
bilateral. 

First  Premolar. — The  crowns  vary  in  the 
development  of  the  inner  cusp ;  if  small  in 
amount  the  tooth  simulates  the  canine,  if  large 
a  second  premolar.  The  tooth  has  often  a 
flattened  appearance  as  though  it  had  been 
squeezed  between  the  tongue  and  cheek. 

The  root  may  be  flattened  and  folded  over; 
a  further  stage  in  this  direction  will  result  in 
the  formation  of  two  separate  roots  placed 
obliquely,  as  in  some  of  the  anthropoid  apes. 
In  the  monkeys  the  roots  are  placed  antero- 
posteriorly. 

Second  Premolar. — These  vary  in  the  develop- 
ment of  either  of  the  inner  cusps  (77,  p.  555). 
This  makes  the  tooth  a  large  size  and  gives  it 
the  appearance  of  a  molar,  the  likeness  being 
accentuated  if  the  adjacent  first  molar  is  small. 

First  Molar. — -Very  Uttle  variation  of  the 
crowns  has  been  noted.  A  four-cusped  instead 
of  a  five-cusped  tooth  may  be  present,  the  small 


43 


external  and  posterior  cusp  disappearing. 
Tomes  (77,  p.  587)  states  that  this  tooth  was 
found  to  have  five  cusps  in  82  per  cent  of  skulls 
examined.  An  extra  cusp  on  the  buccal  surface 
may  sometimes  be  found. 

First  Molar  Roots. — The  anterior  root  is  some- 
times found  to  be  bifurcated  to  any  extent  of 


Anterior, 


Posterior. 

Fig.  60. — Transverse  sections  taken  through  a  first 

mandibular  molar  from  pulp-chamber  to  apices. 

its  length.  A  third  root  is  sometimes  present 
on  the  lingual  and  posterior  aspect  of  the  tooth. 
(Fig.  61.)  This  varies  from  the  size  of  a  hair 
to  a  root  of  equal  importance  to  the  posterior 
root,  which  it  seems  to  displace  outwards.  This 
variation  should  be  looked  for  in  root-canal 
treatment  in  case  the  posterior  root  should  be 

found    to    be   of    small    size   and 

displaced  outwards. 

The   coincidence    of    the    above 

two  variations  would  result  in  a 

four-rooted  tooth. 

Second  Molar. — The  crown  has 

practically  few  variations  from  the 

four-cusped  normal  condition,  but 
often  shows  signs  of  feeble  development  of  the 
cusps. 

Second  Molar  Roots. — The  posterior  root  is 
sometimes  bent  slightly  forwards  ;  this  variation, 
when  accompanied  by  a  slight  backward  bend 
of    the    anterior    root,    frequently   causes    the 


Fig.  fil. 


Fig.  62. 


Fig.  63. 


intervening  portion  of  the  alveolus  to  be  removed 
with  the  tooth.  The  roots  may  sometimes  be 
fused. 

Third  Molar. — The  luimber  of  cusps  varies ; 
the  crortii  may  resemble  that  of  a  first  molar  or 
have  as  many  as  seven  or  eight  cusps.  The 
crown  is  often  very  much  larger  than  normal 
compared  with  the  size  of  the  roots.  Sometimes 
only  a  small  aborted  tooth  may  be  present. 
The  roots  may  be  separate,  as  in  tlie  first  molar, 
or  may  often  be  all  fused  together,  with  the 
backward  curve  well  marked. 


Gemination  (see  page  45). — Gemination  may 
occur  in  all  regions  except  the  canine  (11a) 
(61),  but  is  most  common  in  the  incisor  (Fig. 
62)  and  premolar  regions  (116)  (194),  (Fig.  63). 

A  permanent  tooth  is  more  commonly  gemi- 
nated with  a  supernumerary  tooth  than  with 
another  permanent  tooth.  The  degree  of 
fusion  varies,  sometimes  being  so  complete  as 
to  mask  the  identity  of  the  dual  components. 

Association  of  Abnormalities  of  Structure  and 
Form. — Structures  resembling  teeth  in  greater 
or  less  degree,  and  found  in  place  of  or  supple- 
mental to  the  normal  dentition  will  be  described 
under  the  heading  of  "  Odontomes  ". 

ABNORMALITIES  OF  THE  DECIDUOUS  TEETH 

SIZE. — The  variation  in  size  so  marked  in 
the  permanent  dentition  does  not  occur  to  such 
an  extent  in  the  deciduous  teeth.  The  dentition 
as  a  whole  may  be  composed  of  teetli  slightly 
larger  or  smaller  than  usual,  or  any  individual 
tooth  alone  may  be  so  affected  compared  with 
the  normal  of  such  teeth. 

The  second  molars  and  canines  may  be  found 
sometimes  larger,  or  rarely  smaller,  than 
normal. 

An  upper  or  lower  second  molar  abnormally 
developed  in  the  medio-distal  diameter  may  be 
of  advantage  to  the  patient,  as  it  tends  to  keep 
the  first  permanent  molar  well  back.  Since  the 
second  molars  are  always  larger  in  the  medio- 
distal  diameter  tlian  the  succeeding  premolars, 
a  certain  amount  of  spare  space  is  thus  obtained. 
An  abnormally  large  second  molar  increases  this 
space,  and  allows  extra  latitude  for  normal 
inter-cusping  of  the  upper  and  lower  teeth  as 
they  erupt.  In  like  manner  a  .second  deciduous 
molar  abnormally  short  in  the  medio-distal 
diameter  may  reduce  the  available  space  and 
prevent  normal  occlusion  developing.  It  is 
quite  evident,  therefore,  that  variation  in  the 
size  of  the  teeth  of  the  deciduous  dentition, 
especially  of  tlie  molars  in  the  medio-distal 
diameter,  may  influence  the  future  arrangement 
of  the  permanent  teeth.  Some  upper  and 
lower  second  deciduous  molars  were  measured 
along  their  greatest  medio-distal  diameter  of 
crown.  The  maxillary  «ere  found  to  vary 
from  9"5  to  12  mm.  and  the  mandibular  from 
10  to  11  mm.     (See  Chap.  V,  p.  137.) 

NUMBER. — There  may  be  too  many  or  too  few 
teeth  present,  the  former  abnormality  being  the 
more  comiiion ;  a  few  cases  of  total  absence  of 
deciduous  teeth,  and  in  one  jaw  only,  have  been 
recorded  (39)  (43i). 

The  absence  of  many  teeth  has  been  frequently 
recorded;  this  is  usually  symmetrical,  the 
canines  and  second  molars  alone  being  present. 
The  absence  of  one  or  more  incisors  only  is  a 
rarer  condition,  the  upper  lateral  being  most 


44 


often  absent.  The  absence  of  the  mandibular 
incisors  has  been  repeated  in  the  permanent 
dentition.  The  expectation  that  a  similar 
deformity  will  occur  in  the  permanent  dentition 
should  be  guardedly  adopted  until  a  radiograph 
has  been  taken  to  complete  the  diagnosis. 

No  satisfactory  explanation  of  the  absence 
of  all  or  any  of  the  deciduous  teeth  has  been  put 
forward,  but  it  may  be  noted — 

(1)  The  maxillary  laterals  are  commonly 
absent  in  both  dentitions ;  a  reduction 
in    the    number   of   incisors    from    the 


The  skull  of  a  cat,   showing  the  arrangement  of   the 
incisors. 


Fig.  64a. 

A  plan  showing  the  position  of  the  mandibular  incisors 

of  a  cat. 


typical  is  also  found  in  some  famiUes  of 
the  order  Carnivora,  namely  the  seals 
and  sloth  bears  (Fig.  64c).  The  re- 
duction may  be  presumed  to  be  an 
adaptive  modification  to  suit  the  smaller 
jaws,  consequent  upon  diminution  of 
function  attending  altered  environment 
and  associated  food  supply.  This  loss  is 
foreshadowed  in  another  family,  the 
Mustelidae  (Fig.  64b),  where  the  second 
mandibular  incisors  are  displaced  in- 
wards by  crowding. 

(2)  Cases    are    recorded    of    association    of 

modifications  of  the  hair,  in  quahty  or 
quantity,  with  the  absence  of  teeth 
(15)  (17)  (21)  (37)  in  man  and  lower 
animals  (78). 

(3)  Reduction  in  the  number  of  teeth  occurs 

in  connection  with  various  congenital 
defects,  such  as  cleft  palate. 


These  considerations  must  lend  colour  to  the 
opinion  that  teeth,  being  in  part  of  epithehal 
origin,  are  as  Uable  to  such  variations  as  have 
been  observed  in  other  epitheUal  structures. 


The  skull  of  a  polecat,  showing  the  arrangement  of  the 
incisors. 


'aS'^N 


FiQ.   64b. 

A  plan  showing  the  position  of  the  mandibular  incisors 

of  a  polecat. 

Extra  Teeth  are  only  found  in  the  incisor 
region  and  may  be  either  separate  supplemental 
incisors  or  geminated  to  other  incisors.     Such 


The  skull  of  a  seal  showing  the  arrangement  of  the 
incisors. 


Fig.  64c. 

A  plan  showing  the  position  of  the  mandibular  incisors 

of  a  seal. 

extra  incisors  may  or  may  not  be  followed  by 
similar  extra  teeth  in  the  permanent  dentition. 
They  require  no  treatment  unless  very  unsightly 
or  interfering  with  the  normal  eruption  of  the 
permanent  teeth. 


45 


FORM. — The  shapes  of  the  deciduous  teeth 
are  fairly  constant ;  they  differ  from  the  per- 
manent teeth  in  the  following  characteristics — 

The  colour  is  nearly  always  of  a  bluish  milky 
tinge,  unless  altered  by  extrinsic  or 
intrinsic  stains  (47)  (76).  They  have 
a  squat   appearance   with   a   bulge   of 


_BuIge  of  tissue  at 
the  cinguimn. 


Fig.  65. — Maxillary  deciduous  molar. 

tissue  at  the  cingulum  (Fig.  65) ;  this 
has  been  shown  to  be  an  increase  in  the 
thickness  of  the  dentine  (73),  and  not 
of  the  enamel,  at  this  spot. 

They  have  a  relatively  large  pulp-chamber. 

The  roots  of  the  molars  are  widely  spread, 
and  somewhat  flattened. 

The  roots  have  sharp  apices. 

The  crowns  quickly  show  signs  of  attrition. 

The  chief  abnormalities  of  form  are — 

1 .  Extra  cusps  and  roots. 

2.  Gemination. 

Extra  Cusps  and  Roots — 

The  deciduous  incisors,  both  maxillary 
and  mandibular,  are  usually  normal.  A  case 
showing  bifurcation  of  the  root  of  a  pair  of 
maxillary  incisors  has  been  reported  (60).     The 


Fig.  66. — Maxillary  canine  with  bifurcated  crown. 

maxillary  canine  may  have  a  bifurcated  tip, 
or  a  large  inner  cusp  (4) ;  the  mandibular 
canine  may  be  two-rooted,  as  in  the  perma- 
nent dentition. 

The  first  molars,  maxillary  and  mandibular, 
may    have   a   bulge   on   the   external   anterior 


portion  of  the  cingulum,  which  may  be  exag- 
gerated to  an  extra  cusp. 

The  second  maxillary  molars  may  have  a 
cusp  on  the  anterior  surface  corresponding  in 
size,  shape  and  degree,  ^vith  a  similar  one  to 


Fig.  67a.  Fig.  6Tb. 

First  deciduous  molars,  showing  :  a,  bulge  on  the 
external  anterior  portion  of  the  cingulum ;  B,  enlarge- 
ment to  a  cusp. 

be  noted  on  the  first  permanent  molar.     (See 
p.  41.) 

Second  mandibular  molars  have  commonly 
five  cusps  resembling  a  first  permanent  molar. 


Fig.  68a. 


Fig.  68b. 


Second  maxillary  molars, ]with  extra   cusp  on  anterior 
surface. 

Extra  roots  (or  a  tendency  to  them)  occur  in 
the  lower  canine ;  on  the  post-lingual  surface 
of  the  second  mandibular  molar ;  and  between 
the  anterior  buccal  and  palatine  roots  of  the 


Fig.  69.  Fig.  70. 

Extra  root  on  second  maxillary  and  mandibular 
deciduous  molars. 

second  maxillary  molar,  corresponding  with 
and  similar  to  the  like  condition  met  with  in 
the  permanent  dentition.     (See  p.  42.) 

Gemination. — This    condition    is    a    develop- 
mental   fusion    of   teeth  or  denticles   partiallj' 


46 


or  completely  preserving  the  outline  of  the 
constituents.  This  condition  is  usually  confined 
to  the  incisor  region,  and  is  more  often  met 
with  in  the  deciduous  than  in  the  permanent 
teeth    (11a)  (46)  (57)  (88). 

The  following  explanations  of  this  variation 
have  been  given — 

(1)  It  is  the  result  of  the  fusion  of  two  or 
more  normal  tooth-germs,  or  of  a  normal  and 
a  supernumerary  tooth-germ.  Confirmation  of 
this  may  be  found  in  the  fact,  as  stated  by 
Tomes  (77,  p.  371),  that  (a)  coalescence  of 
rudimentary  tooth-germs  to  form  a  continuous 
sheathing  mass  of  dental  tissues  has  been 
observed  in  a  lizard,  Sphenodon ;  and  (b)  that 
the  shortening  of  the  jaws  of  animals  in  the 
process  of  evolution  has  been  concurrent  with 
the  appearance  of  comf)licated  teeth,  considered 
by  Kiikenthal  to  be  the  fusion  of  two  or  more 
simple  tooth-germs  of  different  dentitions,  and 
by  Marett  Tims  to  be  the  fusion  of  two  germs 
of  the  same  series.  In  this  case  the  sporadic 
appearance  of  gemination  may  be  regarded  as  an 
example  of  atavism. 

(2)  It  is  the  result  of  a  budding  off,  or  rather, 
bifurcation  (dichotomy),  of  the  tooth-germ  and 
subsequent   calcification,    so   that   the   jiroduct 

may  be  two  normal  teeth, 
or  a  normal  tooth  and  a 
supplemental  one. 

The  degree  of  fusion 
varies.  It  may  comprise 
the  whole  length  of  the 
tooth  (Fig.  71) ;  or  the 
crown  or  roots  only  may 
be  fused.  In  cross-section 
a  common  pulp-chamber 
may  be  seen  to  exist,  or 
each  denticle  may  have  its  own  pulp-chamber 
joined  or  not  to  its  twin. 

If  the  teeth  are  joined  by  the  crow^l,  a  section 
will  show  by  the  position  of  the  enamel  on  each 
tooth  that  they  arose  from  a  single  enamel- 
germ,  as  the  enamel  does  not  completely  en- 


FlG.  71. — Geminated 
incisors  :  teeth  united 
their  whole  lengtli. 


Fig.  72. — Cross-section  of  geminated  maxillary  incisors, 
showing  separation  of  pulp-chamber. 

circle  each  component,  and  the  dentine  is 
always  united  (Fig.  72).  Usually  two  teeth 
are  geminated,  but  sometimes  three  have  been 
so  found. 


It  may  be  noted  that  this  deformity  when 
present  in  the  deciduous  teeth  is  not  necessarily 
a  precursor  of  a  similar  condition  in  the  per- 
manent dentition.  The  appearance  of  such 
a  condition  in  both  dentitions  has  been  noticed. 
Hirou  Rodier  (66),  Revue  de  Stomatologie 
(Paris,  Sept.,  1910),  cites  eight  authentic  reports 
in  wiiicli  the  subsequent  iDermanent  teeth  were 
normal,  and  three  cases  of  subsequent  eruption 
of  permanent  geminated  teeth. 

ABNORMALITIES  OF  STRUCTURE 

Cases  of  abnormality  in  the  structure  of 
teeth  may  be  divided  into  two  large  groups — 

(1)  Those  acquired  during  calcification  and 

before  eruption. 

(2)  Those    acquired    after    calcification    and 

eruption,  and  usually  the  result  of 
pathological  processes  in  the  pulp  and 
periodontal  membrane. 

The  latter  cases  wdll  be  described  as  the  natural 
sequelae  in  deahng  with  the  various  diseases 
causing  them. 

Any  departure  from  the  normal  macro - 
scopical  or  microscopical  appearance  must  be 
due  to  an  interference  in  the  normal  growth 
caused  by  a  defective  blood  supply  («'.  e.  de- 
fective in  the  character  of  its  chemical  con- 
stituents, or  laden  with  organisms  and  their 
toxins).  Thus  it  would  appear  that  rickets 
and  syphihs  for  these  reasons  must,  by  their 
effect  upon  the  blood  supply  to  the  developing 
tooth,  cause  a  structural  defect  in  the  tooth 
tissues. 

Attention  has  again  recently  been  called  to 
the  alteration  in  the  structure  and  form  of 
the  finger-nails  (10)  after  severe  illness ;  and  the 
association  of  abnormahties  of  structure  of  the 
'  teeth  with  lamellar  cataract  (8)  would  indicate 
what  a  section  of  such  a  tooth  clearly  shows, 
namely,  that  it  is  on  the  enamel,  which  is  of 
epithelial  origin,  that  the  greatest  effect  is 
produced. 

The  abnormalities  present  vary  in  quantity 
and  degree.  They  are  limited  to  that  area  of 
tooth  which  was  calcifying  at  the  time  of  the 
general  or  local  disorder,  and  may  vary  from  a 
slight  discoloration  of  the  enamel  only,  to  pits 
and  grooves  of  various  depths,  or  entirely 
altered  formation  (such  as  Hutchinsonian  teeth). 
To  such  teeth  the  term  "  hypoplasic  "  has  been 
applied,  super.seding  the  older  terms,  "honey- 
combed ",  etc. 

It  has  been  shown  that  the  calcification  of 
tooth  tissue  is  not  a  continuous  process,  but 
one  of  sliort  bursts  of  activity  followed  by 
intervals  of  rest.  Hence  it  may  happen  that 
a  severe  attack  of  one  of  the  exanthematous 
fevers  may  sometimes  fail  to  harm  the  teeth, 


47 


whilst,  according  to  some  writers,  the  less 
severe  but  long-continued  condition  of  rickets, 
affecting  as  it  does  calcification  in  general, 
seldom  fails  to  leave  its  mark  upon  the  teeth, 
and  is  thus  the  principal  cause  of  hypoplasia. 

Again,  it  is  quite  possible  to  find  hypoplasic 
teeth  the  result  of  a  mild  attack  of  measles. 
The  site  of  the  lesion  is  determined  by  the 
coincidence  in  time  of  the  heiglit  of  the  disease 
and  the  stage  of  calcification  of  tlie  teeth ;  and 
the  degree  of  deformity  is  more  or  less  commen- 
surate with  the  severity  of  the  attack. 

Examples  of  hypoplasia  of  the  deciduous 
teeth  are  rarely  met  with,  but  it  is  obvious  that 
a  severe  constitutional  disturbance  in  the  mother 
during  the  later  months  of  intra-uterine  life 
of  the  foetus  may  produce  these  defects. 

Hyijoplasic  teeth  (5)  (34)  (86,  No.  5,  p.  239) 
may  be  divided  into  t^\o  main  classes — 

(1)  Hypoplasia  caused  by  a  general  disorder, 

and  found  usually  in  several  teeth. 

(2)  Hypoplasia   caused    by   local   conditions, 

and  found  usually  in  a  single  tooth. 

Hypoplasia  of  Malnutrition 

Various  kinds  and  degrees  of  the  condition 
in  this  class  have  been  noted.  The  teeth 
usually  affected  are  the  first  molars,  the  in- 
cisors, and  canines ;  more  rarely  the  first  pre- 
molars, the  second  premolars,  the  second  and 


Fig. 


third  molars,  in  that  order  of  frequency.  In 
all  cases  the  'parts  of  the  different  teeth  affected 
in  the  same  mouth  are  those  that  were  under- 
going calcification  synchronous  with  the  period 
of  the  disordered  nutrition  that  caused  the 
defects  (Fig.  73).     As  regards  the  character  of 


the  defects  themselves  as  shown  in  incisors  and 
canines,  in  slight  cases  it  may  be  merely  an 
opacity  or  discoloration  of  the  enamel ;  in  more 
marked  cases  the  enamel  is  deficient  or  absent 
and  the  surface  of  the  tooth  is  irregular,  rough, 
and  pigmented  (Fig.  74).  In  other  examples 
the  defect  consists  of  a  horizontal  row  of  pits 


(Fig.  75),  or,  if  these  have  coalesced,  of  a  distinct 
encircling  groove,  which  may  be  repeated  at 
intervals,  forming  a  set  of  parallel  grooves 
separated  by  intervals  of  normal  enamel  (Fig. 
76).  In  almost  all  cases  the  portion  of  enamel 
close  to  the  gingival  margins  is  sound. 


Fig. 


Fig.  76. 


It  has  been  observed  that  nearly  all  cases  of 
this  class  may  be  arranged  in  two  groups.  In 
one,  the  enamel  of  the  upper  central  incisors  is 
affected  for  about  one-third  of  the  distance  from 
the  cutting  edge  to  the  gum  margin  (Fig.  77), 
the  upper  laterals  to  a  less  extent  or  not  at  all, 
and  the  upper  canines  only  as  regards  just  the 
tips  (Fig.  78)  ;  in  the  lower  jaw  a  similar  syn- 
chronism is  to  be  noticed,  but  tlie  centrals  and 
laterals  are  affected  to  more  nearly  the  same  ex- 
tent than  is  the  case  in  the  upper,  and  the  lower 
canine  is  more  affected  than  the  upper  canine ; 
from  this  fact  it  may  be  deduced  that  calcifica- 
tion takes  place  earlier  in  the  lower  laterals  and 
canines.    Associated  with  these  defects,  there  is 


48 


to  be  observed  an  abnormal  condition  of  the 
first  molars,  when  this  has  not  been  masked  by 
subsequent  caries.  The  teeth  look  short  and 
stunted,  on  account  of  deficiency  of  the  coronal 
portion,  which  has  a  crinkled,  flattened  and  pig- 
mented appearance.  On  the  other  hand,  just  the 
tips  of  the  cusps  may  usually  be  seen  to  stand  out 


Fig. 


Fig. 


as  little  islands  of  normal  enamel  (Figs.  70,  80). 
Now  it  is  just  these  tips  that  are  calcified 
before  birth,  and  the  whole  state  of  molars  and 
anterior  teeth  indicates  a  depressing  influence 
commencing  at  birth  or  very  shortly  after,  and 
continuing  for  a  variable  period,  a  year  or  more. 
In  point  of  fact  any  condition  of  ill-health  or 


Fig.  79. 


Fig.  so. 


lowered  vitality  during  infancy,  if  sufficiently 
intense,  may  cause  the  defective  teeth,  and 
inasmuch  as  convulsions  and  the  administra- 
tion of  mercury  are  often  associated  with  ail- 
ments during  this  period,  each  of  these  has  been 
set  dow  n  as  the  cause,  but  they  are  concomitant 
or  perhaps  contributory,  rather  than  the  iJriine 
origin.  Some  authors  consider  that  rickets  (84) 
is  the  real  factor,  and  certainly  it  is  a  very 
common  di.sease  in  children  exhibiting  signs 
of  malnutrition ;  but  on  the  other  hand,  rickets 
does  not  iLsually  develop  its  full  intensity  till 
a  somewhat  later  age,  and  certainly  many  cases 
of  hypoplasia  may  be  foiuid  in  which  no  signs 
of  rickets  remain,  and  in  which  no  such  history 
can  be  obtained.  It  is  probable  that  bottle-fed 
children  are  much  more  liable  than  breast-fed 
children,  but  probably  only  because,  on  account 
of  improper  methods,  they  are  more  subject 
to  digestive  disturbances. 

In  the  other  group  of  general  hypoplasia 
the  anterior  teeth  exhibit  the  grooves  or  rings 
described  above ;  the  first  molars  are  usually 
normal.     The  same  synchronism  may  be  seen 


as  in  the  first  group,  but  the  site  of  the  lesion 
indicates  malnutrition  at  a  later  period,  subse- 
quent to  the  calcification  of  the  molars,  which 
will  be  found  to  be  unaffected.  It  is  generally 
in  this  group  that  examples  of  hypoplasic  pre- 
molars may  be  seen,  as  indeed  might  be  ex- 
pected from  the  later  period  of  onset.  Inquiry 
into  the  history  of  these  cases  will  often  elicit 
the  record  of  a  very  definite  iUness,  of  which  one 
of  the  exanthemata,  usually  measles  or  scarlet 
fever,  is  the  most  common  instance.  The 
definite  onset  and  period  is  clearly  associated 
with  the  well-defined  groove ;  in  cases  showing 
two  or  more  rings,  the  cause  of  each  may  be 
discovered  in  separate  illnesses. 

Hypoplasia  of  Local  Origin 

(2)  Inflammation  and  subsequent  suppuration 
around  the  apex  of  a  deciduous  tooth  may  cause 
changes  in  the  underlying  tooth-sac  of  the 
permanent  tooth,  which  when  erupted  may 
show  signs  of  hypoplasia  of  a  greater  or  less 
degree  (82)  (84)  (86,  No.  5,  p.  239). 

Such  teeth  are  quickly  attacked  by  caries, 
which  often  becomes  arrested  and  leaves  the 
tooth  with  a  stunted,  stained  and  polished 
appearance.  The  premolars,  especially  in  the 
mandible,  are  the  teeth  most  commonly  so 
affected,  but  examples  of  other  teeth,  such  as 
the  maxillary  lateral  incisors,  may  be  found. 
It  has  been  suggested  by  J.  F.  Colyer  that 
perhaps  the  condition  might  sometimes  arise 
from  injury  due  to  injudicious  force  in  the 
extraction  of  the  deciduous  molars. 

Microscopic  Structure  of  Hypoplasic  Teeth. 
A  well-marked  Nasmyth  membrane  can  be 
raised  from  these  teeth,  and  it  is  thickened 
in  the  pits  and  crevices  of  the  teeth.  Portions 
of  this  membrane  can  be  raised  from  the 
hypoplasic  portions  of  the  teeth  a  long  time 
after  eruption.  The  extra  thickness  of  the 
membrane  has  been  considered  by  J.  G.  Turner 
to  be  in  part  due  to  uncalcified  or  semi-calcified 
enamel.  As  both  Nasmyth's  membrane  and 
semi-calcified  enamel  are  very  resistant  to 
acids,  the  explanation  may  perhaps  be  found 
for  the  clinical  fact  that  although  hypoplasic 
teeth  by  their  shape  encourage  the  lodgement 
of  food,  they  are  not  more  susceptible  than  other 
teeth.  The  enamel  is  decreased  in  thickness 
and  of  a  poor  quality  as  shown  by  the  deep 
cracks,  fissures,  and  pits.  The  amelo-dentinal 
junction  is  irregularly  defined.  The  brown 
striae  of  Retzius  are  well-marked  and  numerous. 

The  dentine  also  presents  partially  or  poorly 
calcified  portions,  demonstrated  by  the  rows 
of  inter -globular  spaces.  These  failures  of 
dentine  calcification  exist  along  a  line  in  the 
shape  of  a  cone  which  was  once  the  shape  of 
the  formed  dentine  of  the  developing  tooth. 
The    rows    of    inter-globular    spaces    probably 


49 


explain  the  frequency  of  the  association  of 
"  arrested  caries  "  with  hypoplasia  teeth.  They 
allow  the  organisms,  when  once  the  enamel 
has  been  penetrated,  to  grow  quickly  in  a 
lateral  direction  m  tlie  dentine.  Large  super- 
ficial areas  of  tooth  tissue  thus  undermined 
are  removed  by  the  force  of  mastication,  and 
self-cleansing  areas  remain.  The  process  of 
caries  is  for  a  time  arrested,  and  tlie  reaction 
of  the  pulp  has  time  to  manifest  itself  by  the 
production  of  adventitious  or  secondary  dentine, 
which  is  invariably  present  in  these  specimens. 

Syphilis  (42). — Very  few  cases  have  been 
recorded  in  which  congenital  syphilis  has  affected 
the  deciduous  dentition. 

In  the  permanent  series  the  teeth  most  likely 
to  be  affected  are  the  upper  and  lower  incisors. 


Fig.  si. 

the  canines,  and  the  first  molars  (Fig.  81).  The 
incisors  are  described  as  being  of  a  bluish  colour, 
and  barrel-shaped  in  the  crown,  with  a  notch 
in  the  centre  of  the  cutting  edge.  They  are 
smaller  than  would  be  expected.  The  molars 
(1)  (54fZ)  have  smooth  tapering  sides,  with 
small  abrupt  cusps  on  the  coronal  surfaces. 

The  characteristic  appearance  of  the  incisor 
teeth  has  been  explained  (a)  as  the  results  of 
altered  calcification,  due  to  the 
presence  of  the  spirochaeta  pallida, 
which  can  be  demonstrated  in  the 
dental  follicle  (14),  or  (b)  as  the  result 
of  maldevelopment  of  the  middle 
of  the  three  small  cusps  that  are 
normally  present  on  the  edge  of  the 
erupting  incisor,  due  to  early  in- 
cidence of  the  disease.  The  appear- 
ance of  the.se  so-called  Hutehinsonian 
teeth  is  closely  simulated  by  some 
teeth  in  which  the  hypoplasia  is  not  due  to 
syphilis ;  hence  it  \\ould  be  unwise  to  diagnose 
the  presence  of  congenital  syjjhilis  from  the 
appearance  of  the  teeth  alone.  The  diagnosis 
should  be  confirmed  by  an  inquiry  into  the 
family  history,  and  into  the  patient's  early 
history,  as  the  cases  so  often  come  first  under 
the  dental  surgeon's  notice  in  childhood  or  early 
adult  life.  Interstitial  keratitis  is  a  frequent 
accompanving  eye  trouble. 

Dilaceration  (36)  (56)  (SO)  (91).— This  term  is 


applied  to  teeth  having  a  sudden  bend  or  twist 
either  in  the  crown  or  root  portion  (Fig.  82). 

The  cause  is  as  follows  :  A  blow  is  received 
by  the  calcifying  tooth,  either  by  way  of 
the  overlying  deciduous  tooth,  or  through  the 
alveolus,  or  directly  on  to  the  crown  of  the 
erupting  tooth ;  this  tends  to  bend  the  calci- 
fied upon  the  uncalcified  portion  of  the  tooth. 
If  a  section  through  the  position  of  the  sudden 
bend  be  taken,  it  will  be  seen  that  all  the 
dentinal  fibres  are  also  bent,  thus  giving  the 
appearance  of  Schreger's  lines  in  dentine.  The 
rest  of  the  dentine  is  not  as  a  rule  normal. 
Rows  of  inter-globular  spaces  are  often  present, 
with  some  increase  in  the  thickness  of  the 
cementum.  It  has  been  suggested  by  J.  G. 
Turner  (85)  that  the  bending  is  due  to  the 
pressure  of  inflammatory  products,  suppura- 
tion, dental  cysts,  disease  of  the  deciduous 
teeth  or  odontomes,  on  the  tooth-sac  of  the 
developing   tootli. 

Congenital  Hypoplasia. — In  these  cases  the 
enamel  is  either  entirely  absent  or  scattered 
in  patches  about  the  crowiis  of  the  teeth. 
The.se  patches  are  soon  removed  by  attrition, 
and  the  exposed  dentine  becomes  stained  a 
dark  brown  colour.  The  absence  of  enamel 
allows  of  rapid  wear  of  the  dentine,  and  causes 
a  change  of  shape  of  the  teeth,  which  assume 
the  appearance  of  rounded  pegs  and  become 
worn  down  to  the  level  of  the  gums.  Cases 
have  been  published  within  recent  years  by 
Sidney  Spokes  (75),  Norman  G.  Bennett  (7), 
J.  G.  Turner  (83),  and  A.  Hopewell-Smith  (41). 

In  general  the  following  points  may  be 
observed — 

(1)  Apparently  the  deciduous  and  permanent 
teeth  are  equally  affected. 


Fig.  82. 

(2)  The  first-formed  teeth,  namely,  the  in- 
ci.sors  and  premolars,  are  the  most 
affected  ;  the  third  molars  where  noted 
were  normal  teeth. 

(.3)  The  enamel  is  either  absent  or  in  irregular 
masses. 

(4)  The  hereditary  nature  can  be  shown  by 
the  appearance  of  the  condition  in 
various  members  of  the  family  of  an 
affected  parent,  although  a  history  is 
very  difficult  to  obtain.     A  reference  to 


50 


the  original  papers  will  show  that  this 
has  been  noted  as  occurring  through 
four  generations. 

D.  P.  G. 

A.  L.  W. 

BIBLIOGRAPHY 

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(25 
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(31 

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(33 

(34 
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(36 
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(38 
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(40 
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(42 

(43 

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(45 
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(47 
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(49 
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(51 

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Odont.  Soc,  1888-9,  Vol.  XXI,  p.  181. 
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p.  29. 


51 


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(67)  Rogers.      Supernvimerary         Teeth.      Trans. 

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Soc,  1876-7,  Vol.  IX,  p.  252. 


CHAPTER    lA^ 


ABNORMALITIES  OF  POSITION  OF  THE  TEETH  [AND  ABNORMAL 
DEVELOPMENT  OF  THE  ASSOCIATED  PARTS 


Paet    I 
Introduction 

Within  recent  years  a  fuller  knowledge  of 
the  deeper  causes  underlying  abnormalities  of 
position  of  the  teeth  has  considerably  enlarged 
the  scope  of  the  subject.  It  has  become  evident 
that  study  of  the  relations  of  a  tooth  to  other 
teeth  in  the  same  arch,  and  examination  of  the 
shape  of  the  whole  arch,  afford  an  insufficient 
measure  of  the  amount  of  departure  from  the 
normal.  Not  only  is  it  necessary  to  consider 
the  relationship  between  the  two  arches,  but 
also  the  comiection  of  cause  and  effect  between 
abnormahties  of  position  of  the  teeth  on  the 
one  hand,  and,  on  the  other  hand,  the  develop- 
ment of  the  jaws  and  related  bones  of  the  face, 
the  nasal  cavities  and  accessory  sinuses,  and 
the  contour  of  the  lower  part  of  the  face. 

The  teeth  are  constantly  subject  to  the  play 
of  forces  acting  upon  them  in  all  directions. 
The  muscles  of  mastication  produce  conditions 
of  vertical  and  lateral  stress,  the  use  of  the 
tongue  in  mastication  and  speech  reacts  upon 
the  teeth  internally,  and  the  lips  and  cheeks 
in  their  every  movement,  even  of  transient 
emotion,  bring  pressure  to  bear  externally. 
Many  of  these  forces  are  too  sUght  and  of  in- 
sufficient duration  to  produce  any  definite 
movement  of  the  teeth,  but  others  are  constantly 
acting ;  with  the  mouth  shut  and  the  teeth 
closed  the  buccal  cavity  is  obliterated,  and  the 
teeth  are  compressed  between  the  tongue  and 
the  lips  and  cheeks.  Very  little  experience  in 
the  movement  of  teeth  by  mechanical  means  is 
enough  to  show  that  even  a  quite  small  force 
acting  continuously  will  produce  a  considerable 
movement,  and  it  becomes  clear  that  the  teeth 
in  their  arches  are  but  passive  objects  kept  in 
a  state  of  equihbrium  under  the  influence  of  the 
muscles  that  react  on  them  directly  and  in- 
directly. In  adult  life  no  movement  is  produced 
for  two  reasons  :  firstly,  because  the  forces  for 
the  most  part  neutralize  one  another ;  and 
secondly,  because  the  normal  inter-digitation 
of  the  cusps  of  the  teeth  of  the  two  arches  in 
occlusion  prevents  any  slight  movement  taking 
place.  But  during  the  period  of  eruption  the 
developing  teeth  are  guided  into  position  under 
the  influence  of  these  forces,  where  their  space 


52 


has  not  been  encroached  upon,  until  contact 
with  the  opposing  teeth  retains  them  in  normal 
alignment. 

Occlusion  means  hterally  "  shutting  up  ",  and 
expresses  conveniently  the  static  relationship 
of  the  two  arches  when  the  teeth  are  closed  in  a 
natural  manner  with  the  mandible  at  rest. 
Articulation  expresses  the  dynamic  relationship 
of  the  two  arches  during  the  natural  movements 
of  mastication.  It  is  found  that  under  condi- 
tions of  normal  development  the  individual 
teeth  of  either  arch  bear  in  occlusion  a  definite 
incisal  and  cusp  relationship  with  the  opposing 
teeth.  This  is  known  as  "  normal  occlusion  "  ; 
a  description  of  the  details,  being  anatomical, 
does  not  come  within  the  scope  of  this  work, 
but  may  be  found  in  works  on  Dental  Anatomy 
The  term  is  sometimes  extended  in  meaning  to 
include  teeth  and  arches  of  normal  size  and 
shape,  but  as  arches  vary  considerably  according 
to  type  within  normal  limits,  the  usefulness  of 
the  term  is  thereby  lost  in  obscurity.  It  should 
be  restricted  to  the  dental  relationship ;  two 
arches  abnormally  shaped  may  be  in  normal 
occlusion,  and  two  individually  perfect  arches 
may  be  abnormally  related  to  one  another  in 
occlusion. 

Malocclusion  is  any  variation  from  normal 
occlusion  either  of  a  single  tooth  or  several. 
Inasmuch  as  normal  occlusion  is  a  purely  relative 
term,  and  implies  a  particular  form  of  contact 
between  opposing  teeth,  malocclusion  should 
imply  simply  the  negation  of  this  contact,  and, 
strictly  speaking,  if  a  single  tooth  in  one  arch 
is  in  false  alignment  not  only  that  tooth,  but 
the  opposing  tooth  also,  is  in  malocclusion.  In 
practice,  however,  it  is  convenient  to  restrict 
the  use  of  the  term  to  the  particular  tooth 
or  teeth  out  of  position ;  no  difficulty  occurs 
usually  in  the  case  of  teeth  that  are  misplaced 
on  the  buccal  or  lingual  aspect  of  either  arch, 
and  it  is  well  to  make  use  of  the  terms  buccal 
(or  labial)  and  lingual  occlusion  adopted  by 
Angle.  On  the  other  hand,  the  real  relative 
nature  of  the  term  becomes  apparent  in  dealing 
with  cases  where  the  displacement  affects  the 
whole  of  one  or  both  arches.  In  many  cases, 
to  be  discussed  later,  where  the  upper  front 
teeth  are,  or  appear  to  be,  protruded,  the  whole 
of  the  lower  arch  is  too  far  back  in  relation  to 
the  upper  arch,  the  lower  first  permanent  molar 


53 


is  posterior  to  tlie  upper,  and  the  lower  second 
premolar  occludes  with  the  upper  first  molar 
and  second  premolar  instead  of  with  the  two 
upper  premolars.  In  many  such  cases  it  is  a 
moot  point  which  arch  is  misplaced,  although 
as  a  rule  it  is  mainly  or  entirely  the  lower.  It 
is  obvious  that,  strictly  speaking,  both  upper 
and  lower  molars  are  in  malocclusion  although 
one  or  the  other  may  be  perfectly  placed  in  a 
normal  arch.  If  the  term  is  to  be  applied  only 
to  the  tooth  or  arch  misplaced,  its  application 
depends  upon  correct  diagnosis  of  the  case ; 
that  is  to  say,  if  the  upper  arch  is  normal  the 
lower  arch  is  in  malocclusion,  and  is  said  to  be 
in  post-normal  occlusion  with  the  upper,  but 
if  the  upper  arch  is  at  fault,  it  is  in  pre-normal 
occlusion  with  the  lower. 

The  converse  of  the  position  occurs  with  cases 
of  protrusion  of  the  lower  incisors  and  retrusion 
of  the  upper,  but  the  principle  is  the  same. 

Angle  also  uses  the  term  torso -occlusion  for 
a  tooth  rotated  on  its  own  axis,  and  supra- 
occlusion  and  infra-occlusion  for  teeth  unduly 
or  insufficiently  elevated.  For  the  sake  of 
uniformity  and  convenience  these  expressions 
may  be  useful,  but  they  are  a  contradiction  in 
terms,  because  it  is  clear  that  a  tooth  insuffici-  ' 
ently  elevated  is  not  in  occlusion  at  all,  and  one 
that  is  elevated  too  much  can  never  have  been 
in  occlusion. 

In  his  recent  excellent  monograph,  Lischer 
(105)  propounds  a  classification  of  deformities 
considerably  modified  from  Angle,  which  appears 
to  be  scientifically  sound  as  far  as  present 
knowledge  permits.  He  adopts  a  system  of 
terms  based  on  the  two  root-terms  -elusion  and 
-version,  the  latter  practically  corresponding 
with  the  root-term  -clination  adopted  by  the 
writer;  but,  as  in  the  case  of  Angle,  he  uses 
words  like  supraversion,  which  are  in  the 
opinion  of  the  writer  a  contradiction  in  terms. 
The  word  neutroclusion  to  signify  normal 
occlusion  deserves  consideration. 

Inasmuch  as  one  of  the  chief  functions  of  the 
jaws  is  to  carry  the  teeth,  the  form  of  the 
maxilla  and  mandible  is  intimately  connected 
with  the  shape  of  the  arches.  The  alveolar 
portion  more  strictly  belongs  to  the  teeth  and 
is  developed  around  the  roots  wherever  they 
may  be  located,  but  even  so  the  amount  of 
alveolar  deposit  varies  considerably  in  cases 
where  the  arches  resemble  one  another  closely  ; 
in  some  the  roots  may  be  thinly  covered  and 
in  others  there  may  be  considerable  alveolar 
promuience.  Apart  from  this  there  is  no 
definite  demarcation  between  the  alveolus  and 
the  rest  of  the  bone,  the  one  gradually  merging 
into  the  other.  Where  one  arch  is  plainly 
misplaced  too  far  forward  or  back  the  alveolus 
follows,  and  to  that  extent  the  shape  of  the  bone 
is  influenced  by  the  position  of  the  teeth,  but  i 


it  is  probable  that  the  position  of  the  teeth  is 
largely  determined  by  the  growth  and  form  of 
the  maxilla  or  mandible  as  a  whole.  This  is 
seen  in  cases  of  nasal  stenosis  from  adenoids  or 
otherwise,  where  the  expansion  of  the  naisal  cavi- 
ties is  imperfect  and  growth  is  deficient  along 
the  median  suture  of  the  maxillae  ;  the  accessory 
sinuses,  including  the  maxillary  sinus,  partake 
of  this  imperfect  development  and  contribute 
to  the  modifications  in  form  of  the  maxilla. 
In  such  cases  it  is  probable  that  narrowness  of 
the  arch  from  an  early  age  assists  in  the  pro- 
duction of  nasal  insufficiency,  and  it  is  not 
always  easy  to  discriminate  between  cause  and 
effect.  Again,  in  the  case  of  the  mandible  a 
condition  of  post-normal  occlusion  of  the  lower 
arch  is  probably  the  outcome  of  imperfect 
bony  development  about  the  angle,  often 
associated  with  a  contracted  upper  arch,  but 
the  condition  of  post-normal  occlusion,  when 
once  accjuired,  itself  contributes  to  mandibular 
deficiency. 

The  effect  of  the  positions  of  the  crowns  or 
roots  of  the  anterior  teeth  and  the  alveolus 
on  the  physiognomy  and  profile  has  been  well 
emphasized  by  Case,  who  has  clearly  defined  the 
part  of  the  face  thereby  affected  (see  p.  116). 
The  dento-facial  area  extends  from  the  lower 
edge  of  the  bonv  framework  of  the  nose  to  the 


Fig.    83. — Nomial   development    at    3J   years   of   age. 
(J.  Lowe  YouNa :  Dental  Cosmos.) 

mento-labial  fold.  The  free  portions  of  the  lips 
are  mainly  affected  by  the  position  of  the  crowns 
of  the  teeth,  and  the  parts  above  and  below  by 
the  position  of  the  roots  and  the  amount  of 
alveolar  deposit.  The  chin  itself  is  outside  the 
influences  of  the  anterior  teeth,  but  as  the 
development    of   the    mandible    is    intimately 


Fig.  84. — Diagram  to  illustrate  normal  development — the  position  of  the  second  deciduous  molars  and 
the  first  permanent  molars,  and  the  shifting  forward  of  the  first  permanent  molars  whilst  the  pre- 
molars are  erupting.     (Varney  E.  Barnes  :   Trans.  Amer.  Soc.  of  Orthodontists  ;  Items  of  Interest,) 


JJsveLapment     o;    /7?axitlx 
rnU   Outline    :    TtrnpOfaru  ^e/iTure   at    *5'yeara, 
2)one^  Ovtlim    :  X^evelaptd    arch    —     9ye*fj 


.Per.  Centra  L _  .  fyrs. 


^^^^^^       Pcr._  lateral _  _  ,^,f^rs.. 

Fig.   85. — Diagram  from  casts  at  five  and  nine  years  of  age,  to  show  development  in  normal  upper 
arch.     (Varney  E.  Barnes  :   Trans.  Amer.  Soc.  of  Orthodontists  ;  Items  of  Interest.) 


55 


connected  with  tlie  position  of  the  teeth  and  with 
the  occhision,  the  prominence  of  the  chin  is  not 
dependent  solely  on  local  growth. 

It  has  been  shown  by  Cryer  (58)  (59)  that 
marked  differences  occur  in  tlie  growtli  and  form 
of  the  bones  of  the  face  with  which  the  maxilla 
is  connected,  and  these  variations  must  have 
their  effect  on  the  shape  of  the  maxilla  and 
consequently  on  the  shape  of  the  arch.  In 
some  cases  there  is  a  want  of  symmetry  between 
the  two  sides,  just  as  there  is  in  other  j^arts  of 
the  body,  and  the  discrepancy  affects  the  arch 
together  with  the  other  parts  of  the  face. 

Gross  anomalies  in  the  form  of  the  arch  and 
in  occlusion  have  been  thought  to  be  less 
common  in  the  deciduous  than  the  permanent 
dentition,  but  increased  attention  has  shown 
that  they  are  of  quite  frequent  occurrence,  and 
probably  further  investigation  will  prove  that 
most  cases  of  marked  abnormality  connected 
with  defective  bony  growth  really  have  their 
origin  in  quite  early  years.  The  upper  central 
incisors  usually  erupt  somewhat  apart  and  come 
together  by  the  time  the  lateral  incisors  erupt, 


occurring  probably  as  an  inherited  variation, 
or  the  amount  of  overlap  of  the  incisors  may  be 
excessive  (see  p.  136  and  Fig.  234). 


Fig.  86. — Good  development  at  six  years  of  age.     (Norman  G.  Bennett.) 

but  in  some  cases  space  remains  between  the 
centrals,  and  may  exist  between  the  centrals 
and  laterals.  The  incisors  are  usuaUy  more 
vertical  than  the  permanent  incisors,  and  very 
rarely  protrude  except  as  the  result  of  external 
influence,  but  in  some  children  there  is  a 
distmct    lingual    inchnation     of    the     crowns 


Fig.    87. — Commencing  post-normal   occlu.sion  at  five 
years  of  age.     (Strang  :  Dental  Cosmos.) 

During  the  period  of  eruption  of  the  deciduous 
dentition  there  has  been  a  progressive  growth 
of  the  jaws,  most  obvious  posteriorly,  to 
accommodate  the  successive  teeth ;  and  if  de- 
velopment proceeds  on  normal  lines  between  the 
third  and  seventh  years,  dis- 
tinct signs  of  growth  and 
changes  of  form  may  be 
observed  in  both  jaws. 
\Vliereas  at  three  years  of 
age  the  second  deciduous 
molars  are  placed  at  the  most 
posterior  Umits  of  both  jaws, 
at  about  six  years  of  age  a 
considerable  interval  has 
been  provided  by  growth  of 
bone  to  permit  of  the  eruption 
of  the  first  permanent  molars. 
During  the  same  period  it 
may  be  observed  that  the 
anterior  teeth,  \\'hich  were 
formerly  in  close  contact, 
have  become  gradually  separ- 
ated, and  it  is  clear  that  this 
separation  involves  some  de- 
gree of  anterior  translation. 
The  length  of  the  arc  has 
increased,  but  the  curvature 
remains  nearly  the  same; 
that  is  to  say,  the  teeth 
occupy  an  arc  of  a  larger 
concentric  circle  (approxi- 
mately) than  they  formerly 
did.  This  is  well  sho«ii  in 
two  diagrams  by  Varnev  E. 
Barnes  (20)  (see  Figs.  M,  85).  It  seems 
obvious,  therefore,  that  the  anterior  teeth  have 
been  pushed  forward,  and  fresh  deposit  of  bone 
must  have  occurred  behind  the  teeth  and  in  the 
interspaces  between  them  and  probably  on  the 
anterior  aspect  of  the  roots.  This  is  sometimes 
described  as  interstitial  growth  i  the  meaning 


56 


of  the  term  is  somewhat  vague,  but  the  effect 
is  tlie  same. 

Where  occlusion  is  normal,  and  adequate 
spacing  exists  at  the  age  of  six,  it  may  be 
confidently  predicted  that  the  anterior  teeth 
of  the    permanent   dentition    will    erupt  easily 


^^^^^^HR    i^^^^^S| 

1 

Fig. 


-ConirQenciiig  post-iiornial  occlusion  at  five  years  of 

(J.  Lowe 


age — slightly  more  advanced  than  in  Fig.  87. 
Young:  Dental  Cosmos.) 

into  perfect  alignment  (see  Fig.  86).  Un- 
fortunately this  state  of  affairs  is  by  no  means 
the  rule.'  It  has  been  observed,  too,  within 
recent  years  that  a  condition  that  will  ulti- 
mately lead  to  lower  post-normal  occlusion  reaUy 
develops  during  the  period  from  three  to  six 
(see  Figs.  87,  8S).  The 
lower  molars,  instead  of 
occluding  normally  with 
the  upper,  appear  to  fall 
back  and  occlude  only 
with  their  corresponding 
upper  teeth.  A  better 
way  of  regarding  this  is 
to  say  that  the  mandible 
does  not  grow  forwards 
with  sufficient  rapidity 
on  account  of  imperfect 
development  around  the 
crypts  of  the  first  perma 
nent  molars  (and  perhaps 
in  the  ascending  ramus 
and  condyle),  so  that 
the  mandible  gradually 
adopts  a  too  posterior 
position;  it  should  be 
remembered  that  there 
is  but  httle  inter-digita- 
tion  in  the  occlusion  of 
the  deciduous  dentition. 
When  the  first  permanent 

molars  erupt  thev  cannot  come  mto  normal  oc- 
clusion, and  when  the  second  deciduous  molars 

I  J  F.  Colyer  has  brought  forward  evidence  to  show 
that  the  extent  of  spacing  is  connected  with  the  time 
of  closure  of  the  sutures  between  the  pre-maxiUae  and 
maxillae  {Denial  Record,  Feb.  1914,  p.  105). 


are    shed    a    condition    of    lower    post-normal 
occlusion  easily   matures. 

Separation  in  the  canine  and  molar  region  is 
not  usually  so  \\ell  marked,  although  spacing 
occurs  between  these  teetli  in  well -developed 
mouths.  There  is,  however,  some  degree  of  buc- 
cal translation  to  accommodate  these  teeth 
and  the  succeeding  canines  and  premolars 
to  the  enlarged  arch  normally  occupied  at 
eight  years  of  age  by  the  first  permanent 
molars  and  the  permanent  incisors.  This 
increase  of  transverse  width  of  the  arch 
between  the  deciduous  molars  on  each  side 
has  been  demonstrated  by  Sim  W'aUace 
(164)  (see  Fig.  89).  It  is  clear  that  in 
the  incisor  region  fjeripheral  growth  is 
necessary,  because  the  permanent  incisors 
are  much  larger  than  their  predecessors, 
whereas  the  total  medio-distal  width  of  the 
t«  o  premolars  is  somewhat  less  than  that 
of  the  deciduous  molars,  and  spacing  is 
therefore  not  required. 

It  has  been  explained  that  the  growth 
of  bone  between  the  ages  of  three  and 
seven  is  mainly  at  the  back  of  each  jaw 
and  in  the  incisor  region.  The  development 
of  the  bone  is  not  uniform  and  is  closely 
connected  ^rith  the  erupting  teeth  ;  this  applies 
chiefly  to  the  alveolar  portion  but  by  no 
means    solely.     Although    the   purpose   of    the 


Fig.  S'.t. — To  show  increase  in  transverse  width  between  second  deciduous  molars — • 
A,  3i  years;  B,  9 J  years.  The  scale  is  set  at  five  centimetres.  (J.  Sim 
W.\Li..\CF,  :   Trans.  B.S.S.O.  ;  Dental  Record.) 

alveolus  is  to  hold  the  teeth,  the  growth  of 
the  body  of  the  bone  is  necessary  for  the  deposit 
of  the  alveolar  portion,  and  increase  in  length 
occurs  to  a  marked  extent  liefore  and  about  the 
sixth  year.  After  the  eighth  year  there  is  no 
particular  increase  in  the  size  of  the  arch  until 


57 


the  eleventh  year.  The  permanent  canines, 
however,  are  much  larger  than  their  prede- 
cessors, and  it  has  been  explained  that  space  is 
provided  for  them  by  buccal  translation  of  the 
deciduous  canines  and  enlargement  of  the  arch 
in  the  vicinity  ;  but  the  fact  that  grow  th  of 
bone  occurs  about  the  time  of  their  eruption 
is  shown  by  the  observation  that  a  canine  that 
appears  to  liave  little  chance  of  finding  its  way 
into  correct  alignment  will  ultimately  do  so 
(or  very  nearly)  without  adventitious  aid.  The 
upper  canine  is,  however,  more  often  jirevented 
from  coming  into  position  than  any  other  tooth  ; 
either  its  place  has  been  encroached  upon  by 
early  insufficiency,  or  growth  is  inadequate 
about  the  time  of  its  eruption. 

Sometimes  there  is  deficiency  in  growth  in 
width  of  the  arch,  usually  associated  with  other 
deficiency,  and  it  is  wise  in  many  cases  to 
expand  the  arch  while  the  deciduous  teeth  are 
still  in  position.  By  such  means  growth  of  bone 
is  stimulated,  and  the  jiremolars  are  enabled  to 
erupt  into  their  proper  positions.  Expansion 
may  also  be  undertaken  in  case  of  insufficient 
spacing  of  the  deciduous  incisors. 

Hawley  has  measured  casts  of  the  same 
mouths  at  different  ages  and  lias  shown  how 
frequently  growth  in  the  width  of  the  arch  is 
deficient.  Excellent  illustrations  proving  this 
may  be  found  in  Items  of  Interest.  1911 ,  pp.  200-3. 


Fig.  90.- 


-Nornial  eruptiou,  and  vertical  growth  of 
alveolus.     (E.  A.  Bogue.) 


similar  to  what  occurred  at  the  fifth  to  the  sixth 
year,  and  this  is  repeated  somewhat  erratically 
in  the  case  of  the  third  molar  later  on.  In 
addition  to  the  circumferential  and  backward 
growth  described,  there  is  deposit  of  bone  at 


About  the  eleventh  year  backward  growth 
takes  place  rapidly  in  both  jaws  around  the 
developing  second  permanent  molar  in  a  mamier 


Fig.  91. — Two  cases  of  retained  second  lower  deciduous 
molars,  showing  that  the  permanent  teeth  erupt 
to  a  higher  level  than  the  deciduous,  and  that 
vertical  growth  of  alveolus  follows  the  teeth. 
(E.  A.  Bogue.) 

the  inter-maxillary  suture,  wliich  may  partly 
account  for  increase  in  width  of  the  arch ;  and 
also  vertical  development,  especially  about  the 
angle  of  the  mandible,  which  becomes  more 
pronounced  (see  Figs.  90,  91). 

The  process  of  eruption  of  the  upper  molars  and 
its  relationship  to  the  growth  of  the  maxillary 
sinus  has  been  admirably  explained  by  Keith 
(95).  His  description  is  so  clear  that  the  wTiter 
has  quoted  at  some  length  from  his  essay — • 

"  The  relationship  of  the  niaxiUary  sinus  to 
a  wisdom  tooth  in  the  process  of  coming  into 
position  is  shown  in  Fig.  92,  a  representation 
of  a  section  of  the  upper  jaw  of  a  young  man, 
aged  about  19.  The  crown  of  the  tooth  is 
directed  backwards  as  much  as  downwards, 
and  is  embedded  in  the  posterior  border  of  the 
jaw,  just  above  the  alveolar  margin.  Its 
dental  sac  gives  rise  to  an  elevation  in  the  floor 
of  tiie  sinus  or  antrum.  The  sinus  dips  towards 
the  alveolar  margin  behind  the  elevation  caused 
by  the  dental  sac.  The  membrane  lining  the 
sinus  is  very  vascular  where  it  covers  the  eleva- 
tion caused  by  the  dental  sac. 

"  In  Fig.  92  is  also  shown,  by  a  dotted  line, 
the  position  which  the  wisdom  tooth  would 
occupy  were  it  to  complete  its  growth  and  come 


58 


into  use.  As  the  tooth  moves  into  position  it 
rotates,  so  as  to  bring  its  crown  downwards, 
while    the    sinus,    spreading    backwards    and 


<uJh,      \t- 


spheno-maxillary  fossa,  may  be  regarded,  for 
purposes  of  representation,  as  a  fixed  point  in 
the  growth  of  the  upper  jaw;  from  this  point 
the  rest  of  the  jaw  is  thrust  away 
from  the  spheno-maxillary  fossa  by 
the  development  and  growth  of  the 
maxillary  sinus.  By  the  growth  of 
the  sinus,  the  alveolar  margin,  carry- 
ing the  teeth,  is  thrust  away  from 
the  base  of  the  skuU ;  tlie  growth  is 
relatively  greatest  along  its  posterior 
border,  hence  the  rotatory  move- 
ment. 

"  In  Fig.  93  is  represented  four 
stages  in  the  development  of  the 
maxiUary  sinus  in  man.  The  diagram 
is  dra^vn  to  scale  and  is  founded  on 
material  in  the  museums  of  the  Royal 
College  of  Surgeons  and  of  the  London 
Hospital.     Four  stages   are   shown  : 


octuA 


Fig.  92. — Section  of  the  upper  jaw  to  expose  the  maxillary  sinus  in 
a  youth  aged  19.  The  crown  of  the  wisdom  tooth  (M3)  is  em- 
bedded in  the  floor  at  the  posterior  inferior  angle  of  the  maxillary 
sinus.  The  position  of  this  tooth  wlien  erupted  and  the  maxillary 
tuberosity  are  indicated  by  a  dotted  outline.  S.  M.  F.,  Spheno- 
maxillary fossa.  Pt.  PL,  External  pterygoid  plate.  Antr., 
maxillary  sinus.     (Nat.  size.)     (Keith  ;  Brit.  Jour,  oj  Dent.  Sci 


downwards  behind  the  roots  of  the  tooth, 'forces 
the  jaw  forwards  from  the  pterygoid  process, 
thus  elongating  the  alveolus  and  making  room 
for  the  tooth.  The  first  and  second  molar  teeth 
are  brought  into  position  in  a  corresponding 
manner.  All  the  upper  permanent  molar  teeth 
are  developed  in  the  posterior  border  of  the 
jaw,  in  front  of  the  pterygo-maxillary  fissure. 
By  the  growth  of  the  sinus  backwards  and  down- 
wards, the  posterior  or  zygomatic  border  of  the 
superior  maxilla,  containing  the  permanent 
molars,  is  thrust  downwards  into  the  alveolar 
border,  the  molar  teeth  being  thus,  one  after 
another,  brought  into  position. 

"  The  expansion  of  the  maxillary  sinus, 
although  it  is  developed  as  a  diverticulum  from 
the  respiratory  tract,  is  due  only  to  a  slight 
extent,  if  at  all,  to  any  respiratory  or  other 
physical  pressure  exerted  by  tlie  air  within  its 
cavity.  Its  expansion  is  the  result  of  growth 
in  the  strictest  sense  of  the  term,  viz.  by  an 
osteoclastic  ab.sorption  of  bone  beneath  its 
mucous  lining,  and  an  osteoblastic  deposit 
beneath  the  periosteum  covering  the  outer 
surface  of  the  jaw.  Its  growth,  however,  is 
peculiarly  adapted  for  the  purpose  of  making 
room  for,  and  bringing  into  position,  the  upper 
molar  teeth. 

"  The  postero-superior  angle  of  the  maxillary 
sinus,   forming   the   anterior   boundary   of   the 


Fig.  93. — Illustrating  the  growth  of  the  maxiUary 
sinus  in  the  human  jaw.  For  convenience  of 
representation  the  pre-maxillary  part  of  the  jaw 
is  taken  as  the  fixed  point  during  growth.  Four 
stages  in  the  growth  of  the  sinus  are  shown  : 
(1)  At  Birth,  the  outline  of  the  jaw  of  a  newly  born 
child  being  shown  stippled  with  the  sinus  internal 
to  the  second  molar;  (2)  at  the  9th  year;  (3) 
at  the  15th  year ;  (4)  in  the  adult.  S.S.,  Sphenoidal 
sinus;  S.M.F.,  Spheno-maxillary  fossa,  with  the 
Spheno-palatine  opening.  (Nat.  size.)  (Keith: 
Brit.  Jour,  of  Dent.  Sci.) 

(1)  at  birth,  (2)  at  the  ninth  year,  (3)  at  the 
fifteenth  year,  and  (4)  in  the  adult.  For  the 
purposes  of  representation,  that  part  of  the  jaw 
which  carries  the  milk  teeth  is  taken  as  the 
fixed  point.     The  jaw  of  the  newly  born  child, 


59 


drawTi  to  scale,  is  placed  over  the  alveoli  of 
the  teeth  which  succeed  them  in  the  adult 
jaw.  It  vtWl  be  seen  from  the  diagram  how 
the  development  of  the  sinus  lifts  the  orbital 
plate  from  off  the  alveolar  border,  and  while  it 
thrusts  the  floor  of  the  orbit  upwards,  pushes 
backwards  the  posterior  border  of  the  jaw, 
extending  the  alveolar  margin,  until  room 
enough  is  obtained  to  hold  the  molar  teeth. 
Wiile  the  diagram  demonstrates  clearly  the 
growth-changes  which  occur  in  the  jaw,  it  must 
not  be  forgotten  that  in  the  body  the  jwstero- 
swperior  border  of  the  sinus  is  the  fixed,  and  not 
the  moving  point,  as  represented  in  the 
diagram. 


Man 


A. 

B. 

C. 

30 

mm. 

31 

mm. 

10 

mm 

36 

)» 

37 

12 

39 

>> 

38 

15 

50 

)» 

46 

21 

55 

j> 

47 

26 

56 

52 

30 

70 

,, 

54 

40 

At  birth  . 
15  months 
2|  years  . 
9  „  . 
12  „  . 
15  „  . 
Adult 


"  In  the  accompanying  table  certain  dimen- 
sions of  the  upper  jaw  of  man  at  various  stages 
of  growth  are  given.  The  measurements  refer 
to  three  dimensions  of  the  jaw ;  in  column  A 
the  length  of  the  upper  jaw,  measured  from  the 
fronto-maxiUary  suture  to  the  edge  of  the 
central  incisor  crown ;  under  column  B,  the 
length  of  the  alveolar  margin,  measured  in  a 
straight  line  ;  under  C,  the  depth  of  the  posterior 
border  of  the  jaw,  measured  from  tlie  floor  of  the 
orbit  to  the  alveolar  margin.  These  measure- 
ments refer  indirectly  to  the  maxillary  sinus. 
Its  growtli  in  each  direction  is  most  rapid  during 
the  eruption  of  the  permanent  molar  teeth. 
The  alveolus  occupies  practically  the  whole 
depth  of  the  posterior  margin  of  the  jaw  at 
birtli.  While  the  posterior  border  of  the  jaw 
quadruples  its  extent  from  birth  to  maturity, 
tlie  facial  border  becomes  little  more  than 
double,  and  the  alveolar  margin  increases  in 
even  a  smaller  degree.  Growth  adds  to  the 
depth  of  the  posterior  part  of  the  jaw  much  more 
than  to  any  other  dimension,  and  this  addition 
is  entirely  due  to  tlie  growth  of  the  maxillary 
suture. 

"'  The  rapid  growth  of  the  jaw  along  its 
posterior  border,  caused  b}'  the  extension  into 
it  of  the  maxillary  sinus,  not  only  leads  to  the 
forward  rotatory  movement  already  mentioned, 
but  also  necessarily  leads  to  marked  changes  in 
the  growth  of  the  lower  jaw.  At  birth  the 
ramus  of  the  lower  jaw  is  very  short,  and  the 
angle  at  which  it  joins  the  body  of  the  jaw  is 
open.  The  do«iiward  growth  of  the  maxillary 
sinus  leads  to  an  elongation  of  tlie  ramus  of  the 


mandible.  Growtli  in  the  maxillary  sinus  and 
ramus  proceeds — must  necessarily  proceed — 
at  a  corresponding  rate  and  be  closely  correlated, 
but  probably  that  of  the  sinus  is  the  primary 
and  determining  factor.  It  is  tlie  downward 
growth  of  the  maxillary  sinus  that  leads  to  the 
accentuation  of  the  angle  of  the  Jaw;  were  the 
angle  not  accentuated,  only  the  molar  teeth 
would  come  in  contact. 

"  The  development  of  the  sinus  during  the 
eruption  of  the  milk  teeth — at  about  the  15th 
month — is  shown  in  Fig.  94.  The  sinus  is 
spreading  backwards  over  the  sac  of  the  first 


(XmSh. 


s.m.t: 


Fig.  94. — The  development  of  the  maxillary  sinus  in 
a  child  of  fifteen  months  and  the  relationship  to  it 
of  the  dental  sacs  of  the  second  milk  molar  and 
first  permanent  molar.  Antr.,  maxillary  sinus; 
Op.,  Opening  of  sinus ;  S.  M.  F.,  Spheno-maxillary 
fossa;  Pt.  pr.,  External  pterygoid  process. 
*C'ancellous  bones  into  which  the  sinus  is  spreading. 
(Nat.  size.)     (Keith  :  Brit.  Journ.  of  Dent.  Sci.) 

permanent  molar  to  reach  that  of  the  second. 
Over  the  sac  of  this  molar  tooth,  the  bone  is 
markedly  cancellous,  a  porosity  of  the  bone 
always  preceding  the  extension  of  the  sinus  into 
it.  This  is  seen  in  the  specimens  represented  in 
Fig.  94. 

"  Whenever  the  dental  sac  of  a  permanent 
or  milk  molar  is  formed,  an  extension  of  the 
maxillary  sinus  over  it  rapidly  takes  place. 
Thus  a  study  of  the  maxillary  sinus  shows  how 
closely  it  is  connected  in  its  origin  and  develop- 
ment with  the  appearance  and  eruption  of  the 
molar  teeth." 

Keith  further  states  that  in  tlie  higher  apes 
the  size  of  the  maxillary  sinus  varies  inversely 
with  the  size  of  the  inferior  meatus,  and  that  this 
same  relationship  may  be  observed  in  different 
instances  in  man. 

The  average  measurements  of  the  deciduous 


60 


and  permanent  teeth  are  given  by  G.  V.  Black 
(26),  and  phenomena  of  growth  correlated  with 
the  differences  in  size  between  the  teeth  of  the 
two  dentitions  are  well  discussed  by  Simms  (141). 


Fig.  95. — Delicinit  growth  of  luaiidibk'  iii  [jutient  aged 
12  years,  the  result  of  destruction  of  the  joint  at 
the  age  of  eighteen  months.  (iSiR  \V.  Arbuthnot 
Lane  :   Tranx.  Odont.  Soc.) 


Fig.  9U. — Deficient  growth  of  mandible,  the  result  of 
anchylosis  due  presumably  to  injury  at  birth. 
(VV.  J.  PvOE  :  Dental  Cosmos.) 

■Wliile  there  is  httle  doubt  that  the  mere 
presence  of  the  developing  permanent  teeth  in 
their  crypts  is  a  stimulus  to  bony  development, 
it  is  certain  that  a  further  incentive  is  needed, 


and  it  is  highly  probable  that  the  theories 
promulgated  by  Sim  Wallace  (162)  are  correct, 
and  that  lack  of  functional  activity  from  an 
early  age  is  the  main  cause  of  interference  with 
the  normal  process.  If  the  coronal  surface  of 
a  molar  be  taken  as  roughly  twice  the  area  of 
a  premolar  or  deciduous  molar,  the  masticating 
surface  of  an  adult,  including  the  third  molars, 
is  about  three  and  a  half  times  that  of  a  child 
of  three  to  five  years  of  age.  The  weight  of  a 
boy  of  three  is  about  2J  stone,  and  that  of  a 
man  about  IH  stone,  on  an  average,  or  more 
than  four  times  as  much,  so  that  a  child  of  three 


Fig.  97. — Deficient  growtli  of  mandible,  the  result  of 
anchylosis  due  to  injiu'y  at  four  years  of  age. 
(\V.  J.  Roe  :  Dental  Cosmos.) 

is  equipped  with  a  more  efficient  masticating 
apparatus  in  proportion  to  body  weight  than  an 
adult.  It  stands  to  reason  that  these  teeth 
should  be  vigorously  used  in  the  mastication 
of  solid  substances.  Function  is  the  best 
stimulus  to  growth,  whether  by  reflex  stimula- 
tion of  trophic  nerves,  or  by  increasing  vascu- 
larity, or  both,  and  there  can  be  no  doubt  that 
insufficient  mastication  is  responsible  for  much 
imperfect  development  of  the  jaws.  Lawrence 
W.  Baker  (18)  made  experiments  on  young 
rabbits  by  grinding  down  the  teeth  on  one  side ; 
he  found  marked  differences  in  development  of 
the  bones  of  the  skull  between  the  two  sides. 
Sir  W.  Arbuthnot  Lane  (8)  has  recorded  two  cases 
of  deficient  development  of  the  mandible  con- 
sequent on  early  temporo-mandibularanchylosis. 
In  one  case  the  joint  was  affected  at  the  age  of 
eighteen  months,  and  the  effect  on  the  growth 


61 


of  the  mandible  was  profound  (see  Fig.  95). 
Other  cases  have  been  recorded  by  W.  J.  Roe 
<see  Figs.  96,  97). 

Too  much  stress  has  been  laid  in  the  past  upon 
the  distinction  between  the  alveolus  and  tlie 
basal  parts  of  the  jaws.  It  should  be  remem- 
bered that  bone  is  but  connective  tissue,  and 
that  the  chief  function  of  the  jaws  is  to  carry 
the  teeth  and  subserve  the  function  of  masti- 
cation and,  to  a  "less  degree,  speech. 

When  the  child  is  wrongly  fed  on  soft  foods, 
and  the  teeth  are  not  used  with  sufficient 
force  or  for  long  enough  periods,  there  must 
be  not  only  diminished  stimulus  to  growth, 
but  feeble  muscular  development  and  lessened 
blood-supply.  This  applies  to  the  tongue  as 
well  as  to  the  jaws,  and  it  is  probable  that  the 
muscular  growth  of  the  tongue  in  a  child  who 
masticates  properly  and  talks  almost  con- 
tinuously, as  healthy  children  should,  is  an 
important  factor  in  expanding  the  arch  of  the 
teeth  in  both  jaws.  Sim  Wallace  has  rightly 
insisted  on  this  connection  and  so  has  Sir  W. 
Arbuthnot  Lane  (9),  who  has  described  re- 
markable cases  of  open  bite  combined  with 
inferior  protrusion  caused  by  pathological 
increase  in  the  size  of  the  tongue.  The 
question  of  diet  is  further  discussed  as  an 
environmental  influence  under  "  Aetiological 
Factors  ". 

J.  G.  Turner  (154)  has  emphasized  the 
dependence  of  the  position  of  the  teeth  upon 
growth  of  bone,  but  ascribes  defective  growth 
mainly   to   the   presence    of   adenoids.     It    has 


portions  developed  on  normal  lines  (see  Figs. 
98,  99).  He  considers  that  the  defective  part 
is  permanently  damaged  when  its  period  of 
growth  is  past.  On  the  other  hand  cases  occur 
in  which,  in  association  with  adenoids,  the  arch 


Fig.    U'J. — Xatiu'al    widt-'iiiiig    of    arch    in    patk'nl,    wlio 
"outgrew"  adenoids.    (.J.  G.  Turner_:  Brit.  Dent.  Jour.) 

is  narrow  across  the  first  molar  region  but 
considerably  wider  between  the  second  molars, 
even  though  the  adenoids  were  not  removed 
until  after  the  eruption  of  these  teeth  (see 
Figs.  100,  206).  It  would  appear,  however, 
that  a  large  number  of  cases  occur  in  which 
part    or    the    whole    of    the    jaws    are   under- 


Fio.  9=o . — Natural  widening  of  arch  after  removal  of 
adenoids.  A,  A,  second  molars.  (J.  G.  Turner  : 
Brit.  Dent.  Jour.) 

been  pointed  out  that  growth  takes  place  in 
periods  and  sections,  and  Turner  has  shown 
examples  to  illustrate  how  the  growth  of  a  por- 
tion of  the  jaw  while  adenoids  existed  was 
defective    and    remained    so,    although    other 


Fig.  100. — Natural  widening  of  arch  in  region  of  second 
molars.  Age,  about  14  years.  Adenoids  were 
removed  subsequently.     (Norman  G.  Bennett.) 

developed  without  the  existence  of  adenoids, 
and  even  though  it  is  true  that  the  positions 
of  the  teeth  are  secondarily  affected,  there 
is  good  reason  to  think  that  the  growth  of 
bone  is  stimulated  by  muscular  activity  with 
vigorous  use  of  the  deciduous  teeth,  failing 
which  feeble  development  is  at  least  probable. 


62 


Fig.   101. — A  Modern  Englishman.     Note  the  forward   movement  of   7_|  ,    and   tlie  asymmetry  of   the   palate. 
(Half  natural  size.)     {Museum  oj  the  Royal  College  of  Surgeons  0/  England.) 

into  their  correct  position 
is  as  yet  not  fully  deter- 
mined, though  the  ade- 
quacy of  bony  growth 
subsequent  to  tooth 
movement  is  assumed  by 
many  writers. 

Since  it  has  been  recog- 
nized to  what  a  great 
extent  the  shape  and 
size  of  tlie  dental  arches 
and  the  position  of  the 
teeth  influence  the  con- 
tour of  the  lower  part  of 
the  face,  attempts  have 
been  made  to  define  the 
physical  basis  of  beauty 
and  to  prescribe  an  ideal 
type  to  which  the  ortho- 
dontist should  in  his 
treatment  endeavour  to 
conform.  Beauty  is,  how- 
ever, as  much  a  subjec- 
tive impression  as  an 
objective  fact ;  different 
types  appeal  differently 
to  different  people,  and 
as  regards  the  human 
face,  appreciation  is  de- 
rived at  least  as  much 
from  what  is  usually 
called  expression,  or  the 
subtle  effect  of  mind, 
character,  and  habit  of 
thought,  as  from  con- 
figuration of  feature 
Ancient  and  modern  racial  types  are  associated- 
with  their  several  national  ideals  of  beauty,  and 


Fig.  102. 


-Side  view  of  same.     Brachycephalic  and  Orthognathou 
(Half  natural  size.) 


To  what  extent  this  can  be  compensated  for  later 
by  the  stimulus  provided  by  moving  the  teeth 


63 


Fig.  103. — Negro.      (Half  natural  size.)      {Museum  oj  the  Royal  College  oj  Surgeons  oj  England.) 


Fig.  104. — Side  view  of  same.      Prognathous.      (Half  natural  size.) 


64 


Fig.  105. — Chinese.     Not( 


tlie  extreme  width  uf  tlie  arehes.      (Half  natural  .■iize.) 
Boijal  College  of  Suryeons  of  England.) 


[Musciiin  of  the 


Fig.  106. Side  view  of  same.    Note  the  post-normal  occlusion  of  the  mandibular 

teeth.     This  occurs  frequently  in  the  Chinese  skulls  in  the  same  museum. 
(Half  natural  size.) 


what  is  pleasing  to  an  Eng- 
lishman does  not  necessarily 
satisfy  the  ideals  of  a  Rus- 
sian or  Japanese  (3).  The 
form  of  the  dental  arch,  its 
position  in  relation  to  the 
jaws  and  face,  the  degree 
of  prognathism  or  ortho- 
gnathism vary  character- 
istically in  different  races 
(see  Fig.s.  101-112).  In  those 
of  the  more  pure  descent  for 
many  generations,  such  as 
the  Negro  or  Chinese,  the 
variations  in  individuals  of 
the  same  race  is  least 
marked,  but  in  mixed  races, 
like  the  English  and  Ameri- 
can, diversity  of  tyY>e  pre- 
vails. It  should  be  remem- 
bered that  only  about  thirtj'^ 
or  forty  generations  separate 
the  Englishman  of  to-day 
from  the  several  races  from 
whose  fusion  he  derives  his 
inheritance,  and  it  would 
l)e  surprising  if  uniformity 
of  type  had  become  evolved 
ill  so  short  a  time.  It  is, 
then,  necessary  to  recognize 
the  fact  of  somewhat  wide 
diversity  of  form  and  feature 
in  the  skull  and  face,  and  the 
shape  of  the  arch  within 
limits  that  may  fairly  be 
called  normal  is  not  the  least 


65 


variable  factor.  Excellent  profile  photographs 
showing  normal  and  abnormal  variations  and 
types  are  given  in  Lischer's  monograph  (105). 


(e)  The  character  of  the  face  bears  a  dis- 
tinct relation  to  the  character  of  the 
body. 


Fig.  107. — Bushman.      The  arelies  are  small  compared  with  others  sliown,  but  the  Bushmen  are  a 
small  race.      (Half  natural  size.)      (Museum  of  the  Royal  College  of  Surgeons  of  England.) 

The  operator  who  ventures 
so  to  mould  his  jDatient's  jaws 
and  features  as  to  conform  to 
his  own  or  a  theoretical  ideal 
is  exceeding  the  limitations 
of  his  profession  and  courting 
failure.  This  is  not  to  say  that 
vast  improvements  in  ap- 
pearance may  not  be  gained 
by  judicious  treatment  of 
the  teeth  and  alveolus.  So 
true  is  this  that  caution  is 
the  more  necessary,  in  order 
to  avoid  providing  a  patient 
with  a  "  dento-facial  "  area 
out  of  harmony  ^^•itll  the  type 
of  which  he  or  she  happens  to 
be  an  example. 

The  principles  of  art  that 
should  guide  the  orthodontist 
have  been  clearly  enunciated 
by  Henry  Read  (136)  in  a 
short  but  illuminating  article. 
His  conclusions  are — 

(ft)  There  is  no  absolute 
standard  of  human 
beauty. 

(b)  A  relative  standard  can 
be  found  in  the  aver- 

age or  composite. 

(c)  Such  average  or  composite  must  be  con- 

fined to  a  group. 

(d)  Race,    sex,  and    so-called    temperament, 

indicate  the  meaning  of  a  group. 
3 


Fig.  108.- 


Side  view  of  same.     Note  the  vertical  forehead  and  the  prognathous 
jaws.      (Half  natural  size.) 

(/)  Function  may  be  the  ultimate  test  of 
beauty,  but  tliere  are  practical  obstacles 
to  any  effective  application  of  the 
test. 


66 


Fig.   109. — Tasmanian.     Note  the  well-developed  but  nearly  parallel-sided  arches.      (Half  natural  size.) 
{Museum  of  the  Royal  College  of  Surgeons  of  England.) 


Fig.   110. — Side  view  of  same.      Note  the  prognathous  jaws.      (Half  natural  size. 


Fig.  111. — A  Sandwich  Islander. 


Note  the  well-developed  arches.      (Half  natiu'al  size.) 
College  of  Surgeons  of  England.) 


{Museum  of  the  Hoyal 


Much  di.scussion  ha.s 
centred  round  the  problem 
whether  Nature  ever  pro- 
vides teeth  of  a  .size  too 
large  for  the  jaw  and  face, 
and  whether,  therefore,  ex- 
traction is  ever  justifiable. 
Even  if  perfect  osseous  de- 
velopment be  assumed,  it 
is  doubtful  «'hether  in  more 
or  less  recently  mixed  races 
the  blending  of  parts  is  so 
complete  as  never  to  justify 
extraction  for  improvement. 
In  the  breeding  of  animals 
remarkably  inharmonious 
results  may  be  obtained  by 
certain  kinds  of  crossing. 
The  question  is  discussed 
from  the  comparative  stand- 
lioint  by  William  Bebb  (24). 
Undoubtedly  cases  occur  in 
Avhich  very  small  teeth 
widely  separated  are  found 
in  large  jaws,  and  the  as- 
sumption is  that  large  teeth 
occur  in  small  jaws  and 
small  faces.  Cryer  (60)  be- 
lieves that  both  phenomena 
frequently  occur  (see  Figs. 
113,  114,  115,  116,  117). 
Just  as  in  striving  for  an 
artificial  ideal  caution  is 
necessary,  so  it  is  in  determining  whether  the 
teeth  are  really  too  large  for  the  individual  or 
not.     This  question  is  di.scussed  more  fully  in 


Fig.  112.- 


Side  view  of  same.      Dolichocephalic  and  i'l-ognathuus.      (Half 
natural  size.) 

connection  with  hereditary  aetiological  factors. 
(See  pp.  68,  and  71  et  seq.) 

However,  the  real  point  of  the  controversy 


68 


lies  outside  the  realms  of  blending  of  races  and 
genetic  variation ;  the  problem  is  concerned 
mainly  with  environment  and  pliysical  develop- 
ment, and  consists  in  the  question  whether  the 


-Small  teeth  in  large  well-developed  arch. 

(G.    XORTHCROFT.) 

teeth  are  ever  too  large  for  the  jaws  as  they 
exist,  and  whether  the  mechanical  restoration 
of  an  approximately  normal  arch  in  patients 
of  feeble  osseous  development  \rill  be  compen- 
sated for  by  subsequent  bony  growth. 
It  is  undoubtedly  very  difficult  to 
estimate  the  probable  development  of 
of  a  child  who,  for  instance,  at  the  age 
of  eight  exhibits  marked  insufficiency 
in  the  incisor  region,  and  caution  is 
necessary  with  regard  to  early  extrac- 
tion :  but  in  the  opinion  of  the  writer 
bone  formation  is  and  remains  in  many 
cases,  especially  those  associated  with 
nasal  stenosis,  quite  insufficient  to  pro- 
vide space  for  teeth  that  by  inheritance 
are  of  a  certain  fixed  size,  and  restora- 
tion of  a  normal  arcli  with  the  full  com- 
plement of  teeth  can  only  result  in  an 
unpleasing  appearance.  Angle  (6)  has 
published  cases  to  show  how,  after 
treatment  of  a  case  in  which  bony 
growth  is  deficient,  by  means  of  the 
stimulus  of  function,  alveolar  develop- 
ment occurs,  so  that  even  the  apices 
of  the  roots  are  thereby  moved.  How- 
ever, he  describes  a  "working"  retainer 
to  bring  force  to  bear  upon  the  roots 
in  a  labial  direction,  thus  indicating 
that  natural  processes  are  not  always 
sufficient,  or  at  least  very  slow.  A.  H. 
Ketcham  (96)  has  also  published  cases 
intended  to  show  that  extraction  is 
never  justifiable  and  that  expansion  is 
always  compensated  for  by  subsequent 
•■  bone-gro\rth ",  but  the  illustrations  do  not 
altogether  show  ideal  results. 

Cr\-er  (60)  has  shown  a  good  case  in  which  a 
condition  of  anterior  open  bite  was  caused 
during  the  eruption  of  the  posterior  teeth  (that 
the  anterior  teeth  had  been  in  occlusion  was 


shown  by  the  ground-off  edges).  The  case  is 
clearly  one  in  which  there  is  not  sufficient  bone- 
space'  for  the  teeth,  in  spite  of  the  lingual 
position  of  the  second  upper  premolars,  and  in 
which  correction  without 
extraction  would  but  in- 
tensify the  evil.  This  sub- 
ject is  dealt  with  in  detail 
lutder  the  classification  and 
treatment  of  different  types 
of  alinormality. 

Part   II 

Aetiological  Factors 

It     will     presently     be 
shown    that    many    com- 
paratively   simple    abnor- 
malities of  position  are  due 
to  more  or  less  obvious  local  causes ;   but  the 
origin  of  the  more  complex  conditions  associ- 
ated with  defective  formation  of  the  jaws  and 
abnormal    relation    of    the    mandible    to    the 


3i  years. 


Fig.  ll-l. — Small  teeth  in  large  arch.  Note  the  spacing,  and  the 
position  of  the  premolars.  No  teeth  have  been  removed. 
(XoRMAX  G.  Bennett.) 


maxiUa  must  be  sought  for  in  the  influence  of 
pathological  conditions  of  adjacent  parts,  in  the 
environment  and  liabits  of  the  individual 
during  the  period  of  development,  and  in  the 
factor  of  inheritance. 

Heredity. — If  the  skulls  of   prehistoric  man, 


69 


palaeolithic  and  neolithic,  are  compared  vdth 
the  skulls  of  the  modem  Englishman,  striking 
differences  may  be  noticed.     One  of  the  most 


Fig.  115. — Small  teeth  in  large  arches.     (.J.  E.  Sptttfr  ) 


William  Wright  (174)  in  a  short  but  interesting 
communication  gives  measurements  of  the  jaws 
of  skulls  found  in  the  East  Riding  of  Yorkshire. 

Some  belonged  to 
the  Xeohthic  and 
Bronze  ages,  and 
others  to  the  early 
Iron  age.  He 
states  :  ■'  All  the 
measurements  are 
greater  in  the  jaws 
of  the  Stone  and 
Bronze  periods 
than  in  those  of  the 
Iron  period,  and 
tills  is  specially  true 
of  the  bicondyloid 
width  and  the 
Avidth  of  the  ramus. 
Tlie  indices    show 

obvious  is  the  smaller  size  of  the  maxilla  and   |   that  the  earlier  race  was  more  orthognathic,  and 

mandible,   especially  the  latter,  in  relation  to      that   they  had  relatively  wider   pafates  and  a 

the  rest  of  the  skuU  in  the  recent 

tvpes.     It  must  be  at  once  stated 

that     in    many    well-developed 

modem  skulls  this  difference  does 

not    exist    to    any    appreciable 

extent,   but  it  can   scarcely   be 

denied  that    the  counterpart   of 

the  average  mandible  of  to-day 

is  not  to  be  found  among  pre- 
historic and  early  British  re- 
mains.     Valuable     comparative 

measurements  of  the   width   of 

the  arch  and  height  of  the  palate 

in  various   ancient  and  modern 

races  are  given  by  Talbot  (149. 

pp.  49  and  81).    Xot  only  is  the 

modem  mandible  and,  perhaps 

to  a  less  extent,  the  maxilla  also. 

of  smaller  size,  but  their  form 

is    much    more    variable,     even 

within    limits  that   exclude  the 

srrosslv  abnormal  (see  Figs.  118. 

119).' 

It   is  interesting  to  find  that 

an  ancient,  highly  civilized,  and 

to  some  extent  degenerate  com- 
munity— the  Incas  and  Aymaras 

of  Peru — exhibited  many  of  the 

abnormalities  of  position  of  the 

teeth  common  in  the  European 

of  to-day.  tliough  not  to  so  pro- 
nounced   a    degree.     Alton    H. 

Thompson    (150)    has   described 

these    carefully,    but   it   is    not 

evident    to     what     extent    the 

dental  defects  were  due  to  reduc- 
tion in  size  of  the  jaws.     Some  of  those  referred 

to,  however,  seem  to  be  obviously  ascribable  to 

this  cause. 


Fig 


110. — Large  teeth  iii  small  arch.  Space  tor  upper  canmes  (.mierupted) 
obhterated.  Probably  forward  movement  of  upper  molars.  (Xorma>" 
G.  Benxett.) 

smaller  basio-nasal  length .  explaining  the  liigher 
palatal  index  and  the  equal  molar  index,  although 
the  molar  lengths  are  absolutely  greater." 


70 


The  question  at  once  arises,  Is  this  difference 
an  inlierited  character,  the  result  of  gradual 
change  through  successive  generations,  or  is  it 
solely  the  result  of  the  influence  of  external 
conditions,  diet  and  such  like,  operating  during 
the  lifetime  of  the  individual? 

The  problems  of  heredity  have  been  attacked 
in  recent  years  from  \\idely  different  standpoints. 
The  great  generalizations  of  Darwin,  founded 
upon  a  study  of  the  facts  of  variation,  ofiened  up 
large  fields  of  investigation  as  to  the  extent  of 
resemblance  between  parents  and  children  (22) 
(106),  the  material  basis  of  inheritance,  and 
the  reasons  for  the  differences  between  an 
organism  and  its  progenitors ;  and  the  re- 
discovery of  Mendel's  experiments  in  breeding 
has  stimulated  a  large  number  of  workers  to 
investigate  on  the  same  lines  and  accumulate 
further    evidence    in    support    of    his    laws    of 


Fig.    117. — Two  maxillae,  showing  a  large  amount  of  t 
jaw,  A,  and  mucli  less  in  the  larger  jaw,  B.     (Matthew 

descent.  It  is,  of  course,  impossible  to  discuss 
these  various  metiiods  in  detail,  but  it  will  be 
necessary  to  refer  to  such  results  as  have  been 
obtained  bearing  upon  the  form  and  size  of 
the  jaws  in  man.  The  apjalication  of  Mendelian 
metiiods  and  arguments  to  man  is  but  in  its 
infancy.  They  are  primarily  experimental, 
and  the  conclusions  are  based  on  the  numeri- 
cal results  of  first  crosses  and  fertilization  of 
like  forms  in  succeeding  generations  (23)  (72). 
The  classical  experiments  were  made  with  tall 
and  dwarf  jjeas,  in  which  a  first  cross  between 
tall  and  short  always  produced  tall  peas,  but 
fertilization  of  tall  by  tall  in  the  next  genera- 
tion produced  botli  tall  and  short,  and  subse- 
quent union  of  short  and  short  produced  only 
short.  The  quality  of  tallness  is  said  to  be 
dominant  to  the  quality  of  shortness,  which 
is  called  therefore  recessive ;  and  inasmuch  as 
there  is  no  blending,  with  production  of  peas  of 
intermediate  height,  but  rather  transmission  of 
sliortness  througli  a  tall  generation,  the  two 
qualities  are  said  to  "segregate".  The  subject 
is  far  too  complex  to  enter  into  at  all  fully,  but 


references  must  be  made  to  such  investigations 
as  have  been  carried  out  concerning  human 
inheritance. 

Analysis  of  certain  families  with  regard  to 
particular  pairs  of  qualities,  or  the  presence  of  a 
quality  and  the  absence  of  it,  has  shown  that 
the  inheritance  proceeds  according  to  Mendel's 
laws.     Hurst   (72,  p.  102)  has  investigated  the 
problem  of  eye-colour,  and  finds  that  complete 
absence  of  pigment  in  the  front  of  the  iris  is 
recessive  to  the  presence  of  pigment.     That  is  to 
say,  two  blue-eyed  parents  will  have  only  blue- 
eyed  children,  but  two  parents  with  pigmented 
eyes  may  have  blue-eyed  children  in  addition 
to    children    with    pigmented    eyes.     The    two 
characters    of    pigmented    and    non-f)igmented 
are  said  to  "  segregate  ",  and  not  to  produce 
intermediate  forms  that  breed  pure.      Similar 
investigations  have  been  made  with  regard  to 
"  brachydactyly  ",  night- 
blindness,     congenital 
cataract,  and  other  char- 
acters, and  an  explanation 
of  the  want  of  blending  of 
particular    characters    in 
mixed  races  like  the  Eng- 
lish and   American   may 
perhaps  be  found  in  the 
Mendelian   theory ;    it  is 
possible  that  the  applica- 
tion   of    this    method    of 
analysis  to  characters  of 
jaw-form   may    one   day 
afford  important  results. 
The  biometricians.  Gal- 
ton,  Pearson,  and  others 
(72,  p.  41 ),  work  on  differ- 
ent  lines,   and  analyse   the    statistical    results 
derived  from  the  examination  of  a  large  number 
of    individuals    with    regard    to    a    particular 
quality,  to  show  the  varying  amount  of  diverg- 
ence   from    an   average,    and  the  intensity   of 
inheritance.     Galton  formulated  a  physiological 
"law  of  ancestral  heredity",  by  which  a  child 
obtained  on  an  average  half  its  heritage  from 
its   parents,  a  quarter  from  its  grandparents, 
an   eighth    from   its    great-grandparents,    etc., 
the    sum   of    the    series    being   equal    to    one. 
The  prepotencies  or  subpotencies  of  particular 
ancestors   are   eliminated   by  a   law  that  deals 
only  with  average   contributions.     There  is  a 
constant    tendency    tow  ards    an    average ;    as 
Galton    puts    it,     society     moves    as    a    vast 
fraternity,    and    the    law    of    filial    regression 
constantly  neutralizes  the  effects  of  inheritance 
from    abnormal    parents.     Pearson    has    found 
from  statistical  examination  that  the  heritage 
from  the  parents  is  greater,  and  that  from  the 
ancestors   less,    than    by   Galton's   law,    but   it 
remains    a    useful    indication    of    the    average 
expectation.     It   might  certainly    be  expected 


ooth  tissue  in  the  smaller 
Cbyer  :  Dental  Cosmos.) 


71 


that  the  statistical  method  applied  to  dimen- 
sions of  the  jaws  would  lead  to  the  discovery 


acquired    characters    is    now    pretty    generally 
discredited  hy  biologists.     Weismann  (169)  has 


Fig.  118. — Ancient  Egyptian  (female),  prc-clynastio  (4000-(3UOlt  n.c.)  Note  the  well-developed 
arches,  and  the  marked  attrition  of  the  teeth.  (Half  natural  size.)  {Museum  of  the  Royal 
College  of  Stirgeons  of  EiuiUind.) 

of  useful  facts,  as  soon  as 
means  have  been  devised 
for  accurate  measurement. 

The  immediate  jiroblem 
to  be  considered  is :  As- 
suming for  the  sake  of 
argument  that  the  com- 
paratively small  size  of  the 
jaws  at  the  present  day 
is  an  inlierited  quality,  in 
what  way  can  the  diminu- 
tion be  explained  ?  Mucli 
disctission  has  centred 
round  the  question  of  the 
possibility  of  the  inherit- 
ance of  acquired  charac- 
ters, that  is  to  say,  of  a 
character  acquired  as  the 
result  of  external  influence 
during  the  lifetime  of  the 
individual. 

Much  of  this  discussion 
has  been  in  relation  to  the 
inheritance  of  disease,  be- 
cause it  is  difficult  to 
understand  in  many  cases 
how  a  useless  or  harmful 
character,  which  is  appar- 
ently inherited,  should  be 
perpetuated,  except  as  the 
result  of  external  influ- 
ences.     It    is     impossible 

to    discuss    this    question    at    length,    but    the 
Lamarckian   hypothesis   of   the   inheritance   of 


Fig.  US). — Side  view  of  same.      Brachyeeplialie  and  On  liogiiathoiis.      Note  the 
attrition   of  the   teeth.      (Half  natural  size.) 

propounded    and    elaborated    the    theory    that 
influences      affecting      the     "  soma  "     cannot 


produce  a  heritable  result  on  the  germ-cells 
from  which  the  next  generation  is  derived  ;  but 
it  should  be  clearly  understood  that  this  means 
only  that  a  condition  correspondincj  to  any 
acquired  modification  of  a  particular  part,  as 
the  result,  for  instance,  of  use  or  disuse,  cannot 
be  inherited.  Weismann  fully  admits  the  effect 
of  external  conditions,  such  as  temperature, 
on  the  germ-cells,  and  discusses  very  fully  such 
results  in  the  case  of  certain  butterflies.  In  fact, 
Weismann  considers  that  nutrition  (using  the 
word  in  a  wide  sense)  of  the  germ-cells  is  the 
prime  origin  of  the  variations  made  use  of  in 
natural  selection,  and  that  similar  minute 
fluctuations  in  a  large  number  of  the  elements 
of  the  germ-plasm  are  or  may  be  accumulated 
in  the  next  generation  by  the  i)rocess  of  "  amphi- 
mixis " — the  conjugation  of  unicellular  and  the 
sexual  reproduction  of  multicellular  organisms, — 
an  essential  condition  for  the  production  of 
variations. 

It  is  sometimes  assumed  that  if  the  trans- 
mission of  a  small  jaw,  the  result  of  comparative 
disuse,  is  impossible,  no  alternative  exists  to 
regarding  every  small  jaw  as  being  produced 
de  novo  in  each  generation  in  an  individual 
potentially  capable  of  having  developed  a 
normal  one.  Such,  however,  is  not  the  case. 
Weismann  writes  :  "  The  fact,  however,  that 
we  deny  the  transmission  of  the  effects  is  of  no 
importance ;  and  I  have  already  attempted 
to  show  in  former  essays  that  both  use  and 
disuse  may  lead  indirectly  to  variations — the 
latter  in  all  cases  in  which  an  organ  is  no  longer 
of  any  importance  in  the  preservation  of  the 
species,  and  in  which,  so  far  as  the  disused  organ 
is  concerned,  "  panmixia  "  occurs — in  my  former 
essays  sufficient  proof  is  given  to  show  that  the 
gradual  degeneration  of  organs  which  are  no 
longer  of  use  does  not  require  the  assumption 
of  the  transmission  of  somatogenic  variations." 
Again,  "  the  transformation  of  a  species  as  well 
as  the  preservation  of  its  constancy  are  based 
upon  natural  selection,  and  this  is  constantly 
at  work,  never  ceasing  for  a  moment."  "  Every 
species  is  under  the  uninterrupted  control  of 
natural  selection,  as  is  clearly  shown  by  the 
degeneration  of  parts  ^\hich  have  become  useless. 
And  since  the  old  hypotliesis  of  the  transmission 
of  somatic  variations  must,  it  appears  to  me,  be 
definitely  rejected,  this  process  of  degeneration 
can  only  be  explained  as  the  result  of  panmixia, 
i.  e.  the  cessation  of  the  control  of  natural 
selection  over  that  part  which  is  no  longer  of  use. 
Examples  of  such  effects  are  the  rudimentary 
nature  of  the  wings  of  the  Khvi.  a  New  Zealand 
bird,  which  has  gradually  adopted  the  habit  of 
living  on  the  ground  among  the  short  under- 
growth ;  the  acquired  blindness  of  crustaceans 
living  in  caves,  and  of  deep-sea  organisms  ;  and 
the    loss   of   protective    colouring   in   domestic 


animals."  This  cjuestion  of  the  indirect  im- 
portance of  accjuired  modifications  is  discussed 
l)y  J.  Arthur  Thomson  (151,  p.  242).  Now 
although  the  jaws  and  teeth  of  civihzed  man  can 
scarcely  be  described  as  no  longer  of  use,  yet 
there  can  be  no  doubt  that  the  demands  made 
upon  them  for  mastication  are  very  much  less 
tlian  in  the  case  of  primitive  man.  The  reduc- 
tion in  size  is  less  marked  in  the  teeth  than  in 
the  jaws,  except  in  the  case  of  the  third  molars 
and  possibly  the  lateral  incisors.  J.  T.  Carter 
(42),  in  a  valuable  essay  on  the  growth  of  the 
jaws,  states  that  the  teeth  and  tooth-bearing 
parts  change  least  in  the  phylogeny  of  a  race, 
and  the  parts  to  which  muscles  are  attached 
undergo  the  greatest  change ;  and  that  in  the 
progress  of  civilization  the  size  of  the  mandible 
has  become  reduced  out  of  jiroportion  to  reduc- 
tion in  the  size  of  the  teeth.  It  is  probable 
that  the  jaws  and  third  molars  are  chiefly 
affected  in  each  individual  by  diminished 
nutrition  and  blood-supply,  correlated  with 
lack  of  functional  activity  (146).  Such  modi- 
fication is  a  somatic  variation  and  therefore 
not  directly  inheritable,  but  it  can  scarcely  be 
argued  that  some  of  tlie  very  aberrant  forms 
of  third  molar  are  solely  the  result  of  external 
influences  during  their  growth,  and  it  seem.s 
reasonable  to  suppose  that  the  degenerative 
adaptation  in  each  generation  serves  in  the  way 
described  by  Weismann  as  the  cover,  as  it  were, 
for  a  gradual  blastogenic  variation  leading  to 
reduction.  Russel  Wallace  gives  the  human 
jaw  as  an  example  of  regression  due  to  non- 
continuance  of  selection.  This  explanation  is 
probably  far  nearer  the  truth  than  anything 
founded  on  the  principle  of  "reversion". 
Incomplete  reversion  to  a  comparatively  recent 
ancestor  is  occasionally  observed  in  man,  but 
should  produce  a  well-formed  jaw  rather  than  a 
diminished  one  ;  reversion  to  remotely  ancestral 
types  is  common  only  in  the  production  of 
hybrids  in  plants  and  animals,  but  occasionally 
occurs  in  man — for  instance,  in  the  form  of 
superiuimerary  nipples.  Weismann  remarks : 
"  It  is  well  known  that  organs  which  have  lost 
their  value  in  the  preservation  of  the  species 
become  rudimentary  in  the  course  of  genera- 
tions ;  they  diminish  in  size,  become  stunted 
and  ultimately  disappear  altogether."  The  re- 
duction and  disappearance  of  parts  by  atrophy 
is  in  fact  an  essential  part  of  evolutionary 
processes  (29)  (68).  Such  organs  occasionally 
reappear  by  reversion ;  if  this  ever  takes  place 
in  tlie  case  of  the  jaws  it  should  be  in  the  form 
of  increased  rather  than  diminished  size. 

But  quite  apart  from  diminished  size,  there 
exists  considerable  diversity  in  the  form  of  the 
jaws  in  modern  man  within  the  limits  of  the 
normal.  It  has  already  been  pointed  out  that 
to  expect  aU  ja«s  and  arches  to  conform  to  an 


73 


ideal  or  canonical  contour  is  not  logical.  Marked 
differences  exist  in  the  shape  of  the  parts  of  the 
body,  especially  of  the  skull  and  bones  of  the 
face,  and  there  is  no  more  reason  to  label  a 
retrousse  nose  as  abnormal  than  an  aquiline 
one.  It  is  almost  certain  that  such  variation 
in  the  form  of  the  ja\\s  and  arches  is  of  blasto- 
genic  origin,  and  often  very  definitely  inherited 
from  generation  to  generation.  It  would, 
indeed,  be  strange  if  this  were  not  so.  When 
striking  resemblances  are  found  to  exist  between 
parent  and  child  in  the  colour  of  a  moustache, 
the  curve  of  an  eyebrow,  and  even  passing 
expression  the  result  of  transient  emotion,  tricks 
of  manner,  and  habits  of  thought,  it  would 
surely  be  very  remarkable  if  the  form  of  so 
variable  a  part  as  the  ja\\s  were  not  inherited. 
Perhaps  the  most  extreme  examples  within 
normal  limits  are  some  of  the  moderately  well- 
defined  laterally  contracted  arches  in  \\hich 
occlusion  is  normal ;  but  other  slight  peculiarities 
are  frequently  inherited,  and  no  doubt  forms 
clearly  abnormal  also  are. 

The  c£uestion  arises,  to  what  extent  inherit- 
ance may  be  from  one  parent  or  both  or  from 
grandparents  and  so  on,  with  regard  to  parti- 
cular characters.  As  Weismann  says  :  "Three 
principal  kinds  of  combination  have  to  be 
considered  in  any  attempt  to  explain  the 
blending  of  parental  characters  in  the  child. 
These  are:  (1)  the  characters  of  the  child  are 
intermediate  between  those  of  the  parents ;  (2) 
the  child  exclusively  or  principally  resembles 
one  parent ;  and  (3)  the  child  resembles  the 
father  as  regards  some  characters  and  the 
mother  in  respect  of  others."  These  kinds  of 
inheritance  have  been  termed  respectively 
blended,  exclusive,  and  particulate  (151,  p.  106). 
It  is  the  third  that  bears  upon  the  question 
of  jaw-formation.  The  fact  that  a  child 
often  resembles  one  parent  very  markedly 
in  certain  characters,  and  the  other  parent  in 
other  characters,  is  familiar  to  every  one ; 
it  is  necessary  to  consider  whether  this  is  true 
only  on  broad  lines,  or  whether  it  may  be 
fairly  applied  even  to  small  details.  One  of 
the  reasons  sometimes  given  for  the  condition 
in  which  the  jaws  do  not  appear  to  be  large 
enough  to  jDermit  normal  alignment  and  occlu- 
sion of  the  teeth,  is  that  small  jaws  may  be 
inherited  from  one  parent  and  large  teeth 
from  the  other.  This  argument  is  treated  with 
scorn  by  several  writers,  but  curiously  enough 
neither  the  propounders  nor  opponents  of  the 
view  give  very  adequate  reasons  for  their  belief. 
It  is  said  by  the  latter  that  it  would  be  as 
reasonable  to  expect  a  child  to  inherit  a  large 
hand  from  one  parent  and  a  small  hand 
from  the  other.  But  as  Weismann  points  out, 
in  the  bilaterally  symmetrical  human  being 
paired  organs  are  nearly  always  similar ;  the 
3* 


method  of  development  makes  this  probable, 
and  any  argument  drawn  from  observation 
of  symmetrical  parts  and  apphed  to  unpaired 
organs  is  fallacious.  Even  paired  organs  are  not 
always  alike.  Weismann  writes  :  "  One  brown 
and  one  blue  eye  sometimes  occur  in  dogs, 
especially  in  boar-hounds,  and  I  know  of  a 
similar  instance  in  the  human  subject :  the 
father,  a  brewer  in  a  small  suburban  town,  has 
blue  eyes,  and  the  mother  brown  eyes,  while  a 
daughter  of  twelve  years  of  age  has  one  blue 
and  one  brown  one." 

As  a  matter  of  fact  the  particulate  inheritance 
from  the  two  parents  extends  to  characters 
of  almost  minute  detail.  The  jjoint  is  import- 
ant, and  so  well  discussed  by  Weismann  that 
the  writer  ventures  to  quote  at  some  length — 

"  A  child  may  closely  resemljle  its  mother  as 
regards  the  arms  and  hands,  and  nevertheless 
may  take  after  its  father  in  respect  of  the  legs 
and  feet.  The  form  of  the  skull  may  resemble 
that  of  the  father  and  the  face  that  of  the 
mother ;  or  the  form  of  the  entire  head  and  face 
may  be  like  the  mother,  while  the  eyes  may  be 
similar  to  the  father's  in  every  detail.  The 
son  may,  like  his  father,  po.ssess  a  dimple  on  the 
chin,  although  he  takes  much  more  closely 
after  his  mother  as  regards  the  shape  of  the 
face  and  nose.  That  the  combination  of  parental 
characteristics  may  even  extend  into  far  greater 
details  is  shown  especially  by  the  remarkable 
amalgamation  of  the  mental  qualities  of  the 
parents  which  often  occurs.  The  intellect  and 
practical  talent  may  be  inherited  from  the 
mother,  and  .strength  of  will  and  unselfishness 
from  the  father  :  and  all  these  qualities  may  be 
contained  in  one  skull,  the  form  of  which 
essentially  resembles  that  of  one  of  the  parents 
only.  " 

It  must,  of  course,  be  admitted  that  there  is 
a  very  close  correlation  in  growth  between  the 
teeth  and  the  jaws,  which  should  tend  to  oblite- 
rate any  want  of  adaptability  derived  from 
particulate  inheritance ;  but  in  view  of  the 
statement  above,  of  which  the  truth  may  be 
substantiated  by  the  careful  observation  of 
any  one,  it  is  obvious  that  the  theory  of  the 
large  teeth  in  the  small  jaw  must  not  be  con- 
temptuously swept  aside  without  more  cogent 
proof  of  it's  absurdity.  The  writer  does  not, 
however,  wish  to  suggest  that  it  is  at  all  a  frequent 
phenomenon.  It  is  probable  that  a  more 
reasonable  explanation  of  many  cases  is  to  be 
found  in  the  view  previously  suggested  of 
retrogression  of  the  jaws,  from  imnmixia,  more 
ra])icl  than  retrogression  of  the  teeth  ;  and  it  is 
still  more  probable  that  in  most  cases  the  factor 
of  lack  of  function  and  nutrition  during  growth 
is  the  most  important  of  all.     This  will  presently 


74 


be  considered.  J.  Lowe  Young  (177)  states  that 
bony  insufficiency,  and  consequent  abnormality 
in  position  of  individual  deciduous  teeth,  are 
rare,  and  he  deduces  from  this  that  inheritance 
plays  a  small  jjart  in  the  production  of  abnor- 
malities of  the  permanent  dentition.  The 
argument  is,  however,  fallacious,  as  inherited 
characteristics  often  appear  only  at  certain 
stages  of  development,  and  inherited  reduction 
in  the  size  of  the  jaws  would  not  be  expected 
to  show  itself  in  quite  early  years.  [See  J.  E. 
Spiller  (143).] 

It  has  been  sometimes  observed  that  certain 
some^^hat  abnormal  forms  of  jaw,  such  as  an 
arch  slightly  contracted  laterally,  is  transmitted 
through  several  generations,  although  only 
through  one  parent  in  each.  Historical  in- 
stances of  this,  sometimes  cited  (93)  (151,  p. 
112)  (169,  p.  290),  are  the  high  forehead  and 
widely  separated  eyes  of  the  Caesars,  the  hooked 
nose  of  the  Bourbons,  and  the  inferior  protrusion 
of  the  reigning  dynasty  of  Spain.  Such  indi- 
vidual prepotency  is  a  familiar  phenomenon 
to  breeders  of  stock,  who  have  often  found  that 
certain  individual  animals  have  a  remarkable 
power  of  transmitting  their  characteristics  to 
a  majority  of  their  progeny.  It  is  one  that  must 
distinctly  be  taken  into  account  in  considering 
the  heredity  of  various  jaw-forms. 

Explanations  of  diminished  size  of  the  jaw 
expressed  in  general  terms,  such  as  civilization, 
crossing  of  races,  and  sexual  selection,  are  not 
of  much  value  unless  the  exact  method  by  which 
gradual  changes  may  have  been  brought  about 
are  discussed.  That  the  jaws  are  reduced  in 
most  civilized  races  is  an  undoubted  fact,  and 
the  direct  effect  in  each  generation  of  modern 
environment  and  methods  vaW  presently  be 
considered.  But  if  the  reduction  has  been 
gradual  it  is  not  necessary  to  have  recourse  to 
"  use  inheritance  "  for  an  explanation,  or  to 
try  to  show  that  civilized  races  have  actually 
benefited  in  the  struggle  for  life  by  a  slight 
decrease.  It  should  not  be  forgotten  that  in 
the  processes  of  evolution  progressiv'e  atrophy 
plays  a  part  almost  as  important  as  increase, 
in  successive  generations.  There  is  competition 
between  organs  as  well  as  between  individuals 
and  between  species,  and  the  balance  between 
the  nutrition  of  different  organs  may  be  con- 
ceived of  as  correlated  with  their  degrees  of 
usefulness,  without  implying  the  direct  inherit- 
ance of  small  size  from  diminished  use  from 
one  generation  to  the  next.  Sim  Wallace  (162, 
p.  159)  refers  to  the  fact  that  the  American 
negro  has  in  a  few  generations  become  more  or 
less  orthognathous,  and  considers  that  restora- 
tion to  original  surroundings  would  at  once 
produce  a  new  generation  of  the  original  form. 
However  this  may  be,  it  is  pretty  clear  that  some 
blastogenic    variation    of    a    retrogressive    kind 


I  has  taken  place,  because  if  the  effect  were  the 
outcome  of  external  influences  acting  de  novo 
in  each  generation,  there  is  no  reason  why  it 
should  not  have  been  brought  about  in  a  single 
generation  instead  of  a  jew. 

The  question  of  the  influence  of  the  crossing 
of  races  has  already  been  referred  to  in  connec- 
tion with  "  reversion  ".  There  is,  as  Sim  Wallace 
points  out,  no  reason  to  think  that  the  crossing 
of  diverse  types  would  result  in  reduced  jaws, 
but  rather  the  other  way.  On  the  other  hand, 
a  recently  mixed  race  like  that  of  the  United 
States  and,  to  a  less  extent,  of  Great  Britain, 
may  be  expected  to  have  blended  less  completely 
than  an  older  race,  and  the  various  phenomena 
of  "  particulate  "  inlieritance  from  the  two 
parents  are  likely  to  be  more  frequent  and  more 
pronounced.  This  question  cannot  be  set  aside 
by  a  general  condemnation  of  the  large  teeth 
and  small  jaw  theory.  The  question  of  sexual 
selection  need  not  be  more  than  referred  to, 
for  there  is  no  evidence  that  imperfectly 
develoj)ed  jaws  in  the  "oval  face",  and 
abnormal  alignment  of  teeth,  are  regarded 
by  a  majority   as  features  of  beauty. 

Talbot  (148)  (149)  has  investigated  in  remark- 
able detail  the  question  of  the  relation  between 
various  forms  of  mental  and  physical  degeneracy 
and  abnormal  or  defective  formation  of  the 
maxillae  and  other  bones  of  the  face.  While  it 
may  be  admitted  that  he  gives  a  large  number 
of  cases  that  show  some  such  deformities,  it 
cannot  be  said  that  he  has  at  all  proved  that 
such  deformities  as  a  laterally  contracted  arch, 
for  instance,  are  really  pathognomonic  of  con- 
stitutional degeneracy.  It  is  not  unnatural 
that  defective  development  should  manifest 
itself  in  the  jaws  as  well  as  in  other  parts  or 
organs  of  an  individual  of  a  degenerate  type ; 
but  in  the  opinion  of  the  writer,  Talbot,  regard- 
ing such  phenomena  from  an  hereditary  stand- 
point, gravely  underestimates  the  effects  of 
lack  of  function  in  mastication  during  growth, 
and  pathological  conditions  such  as  adenoids, 
both  presently  to  be  considered. 

It  is  important  to  remember  that  defective 
bone-formation  is  not  a  disease,  and  considera- 
tion bearing  upon  the  question  of  direct  inherit- 
ance of  predisposition  to  certain  diseases,  such 
as  tuberculosis  and  cancer,  do  not  apply. 
Furthermore,  whatever  may  be  the  inherited 
variations  in  the  direction  of  defect  of  any  kind, 
it  is,  after  all,  the  normal  that  constantly  tends 
most  strongly  to  be  reproduced.  This  point  is 
well  brought  out  by  J.  Howell  Evans  (69, 
p.  98). 

In  the  course  of  the  foregoing  brief  arguments 
the  writings  of  Weismann  have  been  frequently 
quoted,  firstly,  because,  although  his  views  have 
not  been  by  any  means  accepted  in  their 
entirety,     they    have     exercised     a    profound 


75 


influence  on  the  trend  of  thought  in  biology,  and 
secondly,  because  his  main  contentions  have 
sometimes  been  misapplied  in  connection  with 
the  problem  of  abnormal  jaw-formation  and 
dental  alignment. 

Environment. — Whatever  may  be  the  extent 
of  the  influence  of  heredity,  there  can  be  no 
doubt  that  the  effect  of  environment,  in  its 
widest  sense,  during  the  growth  of  the  individual 
is  of  vast  imfiortance. 

The  growth  of  the  jaws  is  dependent,  as 
other  parts  are,  on  general  nutrition  and  con- 
stitutional conditions  of  vitality  or  depression, 
and  it  can  hardly  be  expected  that  an  ill- 
nourished  child  will  have  jaws  anything  like 
as  '\\ell  developed  as  they  might  have  been 
under  happier  circumstances.  When  assimila- 
tion and  metabolic  activity  are  sub-normal  the 
vital  organs  absorb  most  of  the  supplies,  and 
the  bones  and  other  relatively  less  important 
connective  tissues  suffer.  Whether  the  teeth 
share  in  this  defect  is  uncertain ;  temporary 
malnutrition  associated  with  a  period  of  acute 
iUness  causes  hypoplasia  of  enamel,  but  it  is 
not  very  probable  that  normally  formed  teeth 
are  developed  on  a  reduced  scale  as  the  result 
of  general  malnutrition.  In  any  case  they  are 
mostly  calcified  long  before  the  completion  of 
the  period  during  which  deficient  nutrition  in 
childhood  occurs,  and  it  is  extremely  likely 
that  many  children  with  normal  teeth  are 
stunted  in  growth,  and  have  jaws  not  large 
enough  to  permit  of  normal  alignment  and 
occlusion.  Those  who  beheve  that  correlative 
growth  of  the  jaws  will  always  bring  this  about, 
with  or  without  the  aid  of  mechanical  means, 
are  expecting  too  much  from  the  jaws  of  a 
stunted  child. 

But  the  local  effect  of  lack  of  function  is  more 
important  than  the  results  of  general  mal- 
nutrition. Function  stimulates  growth ;  this 
is  particularly  true  of  muscle,  and  also  of  bone, 
in  so  far  as  it  is  the  means  of  muscular  attach- 
ment. The  length  of  a  long  bone  will  not  be 
increased  by  excessive  use,  although  it  should 
be  remarked  that  after  such  a  disease  as  infantile 
paralysis  normal  length  is  not  usually  attained ; 
but  the  size,  density,  and  form,  of  such  bones 
as  the  maxilla  and  mandible  vary  according  to 
the  e.xtent  to  which  they  are  used  during  the 
period  of  growth.  The  dependence  of  the 
structural  formation  of  the  inner  as  well  as 
superficial  parts  of  the  mandible  upon  muscular 
tension  has  been  demonstrated  by  Walkhoff 
(146).  Sim  Wallace  points  out  that  in  such 
races  as  the  negro  and  aboriginal  Australian, 
not  only  are  the  jaws  wide  and  well  developed, 
but  the  malar  bones  are  pronounced  and  broad, 
and  in  the  latter  race  the  squamous  portion 
of  the  temporal  bones  is  so  much  enlarged 
that  it  articulates  with  the  frontal  bone.     In 


those  races  who  use  the  jaws  adequately  the 
maxilla  and  arch  of  the  teeth  (and,  of  course, 
the  mandible  also)  are  usually  brought  more 
forward  during  development  than  in  other  races. 
The  backward  position  of  the  arches  in  ortho- 
gnathous  tyi^es  has  been  w  ell  described  by  Cryer 
(58)  (146).  But  it  must  not  be  supposed  that 
prognathism  is  necessarily  associated  with 
function,  for,  as  Harry  Campbell  (40)  remarks, 
certain  hill  tribes  of  North-East  India  have 
jaws  that  are  comparatively  short  antero- 
posteriorly.  These  quaHties  are,  of  course, 
racial  characteristics  and  are  inherited  (not 
necessarily  as  the  cUrect  result  of  use-modifica- 
tion), but  it  can  hardly  be  doubted  that  jaws 
of  diminished  size  in  civilized  man  are  frequently 
the  chrect  result  of  lack  of  function  in  childhood. 

The  exact  nature  of  the  process  is  uncertain, 
but  probably  diminished  vascularity  and  com- 
parative stagnation  of  lymph  are  chiefly  respon- 
sible, and  possibly  want  of  stimulus  of  trophic 
nerves.  The  question  is  well  discussed  by 
Harry  Campbell  (40).  Sim  Wallace,  who  has 
given  much  attention  to  this  subject,  considers 
that  the  chief  result  of  deficient  mastication 
is  imperfect  dev^elopment  of  the  tongue,  and 
that  the  tongue  is  an  important  factor  in 
ensuring  normal  develoj)ment  and  expansion 
of  the  jaws.  Muscle  tissue,  it  is  true,  probaljly 
responds  to  exercise  to  a  greater  extent  than 
any  other  tissue,  and  there  is  much  to  be  said 
for  Sim  WaOace's  contention ;  he  has  himself 
adduced  many  arguments  in  support  of  his 
theory,  though  it  should  be  remarked  that 
fibrous  food  requiring  much  mastication  is  not 
necessarily  the  kind  of  diet  that  gives  most 
exercise  to  the  tongue  ;  soft  sticky  foods  like 
suet  pudding  require  much  activity  on  the  part 
of  the  tongue.  The  facts,  so  far  as  they  are  at 
present  known,  hardly  endorse  the  idea  that  the 
tongue  is  the  aU-important  factor;  for  the 
reasons  already  given,  it  is  probable  that  the 
effect  of  the  stress  of  mastication  on  the  growth 
of  the  jaws  themselves  is  very  considerable.  It 
is  no  uncommon  experience  to  find  that  children 
from  two  to  six  years  of  age  and  later  are  fed 
almost  entirely  on  soft  foods,  paps,  and  puddings, 
which  discourage  all  use  of  the  teeth,  and  un- 
fortunately this  erroneous  method  of  feeding  is 
advocated  in  many  otherwise  excellent  medical 
works.  Such  methods  are  productive  of  many 
evils,  among  which  one  of  the  chief  is  the 
prevalence  of  dental  caries ;  the  subject  is 
fully  discussed  in  the  chapter  on  its  aetiology, 
and  has  been  referred  to  in  connection  with  the 
development  of  the  jaws  in  the  first  section  of 
this  chapter,  and  need  not  therefore  be  more 
fully  dealt  with  here. 

Pathological  Influences.  —  In  a  subsequent 
chapter,  the  various  types  of  abnormahty  of 
position  of  the  teeth  associated  with  abnormal 


76 


development  of  bone  will  be  described  in  detail. 
Many  of  these  cases  are  associated  with  mouth- 
breathing,  and  it  will  be  convenient  to  discuss 
briefly  at  this  point  the  general  effects  of  nasal 
obstruction  on  the  growth  of  bone  and  the  con- 
formation of  the  dental  arches.  The  relation- 
ship between  mouth-breathing  and  dental 
disease  and  deformity  of  the  jaws  was  recognized 
many  years  ago,  and  a  paper  by  Scanes  Spicer 
(142)  on  the  subject  pubhshed  in  1890  is  well 
worth  reading  at  the  present  day.  Mouth- 
breathing  is  sometimes  spoken  of  as  a  habit, 
but  it  is  almost  certain  that  the  habit  is  in 
nearly  every  case  a  compulsory  one,  and  arises 
from  inability  to  inliale  a  sufficient  quantity 
of  air  through  the  nasal  passages  on  account 
of  obstruction  at  one  part  or  another.  The 
most  usual  source  of  obstruction  consists  in 
hypertrophy  of  Luschka's  tonsil  situated  in  the 
naso-pharynx,  commonly  known  as  "  adenoids  ". 
This  is  usually  associated  with  hypertrophy  of 
the  faucial  tonsils,  which,  although  not  of  itself 
likely  to  impede  nasal  breathing,  probably 
assists  in  obliterating  the  pharyngeal  air-way. 
Nasal  obstruction  may  also  be  caused  by  devia- 
tion of  the  septum,  but  as  simple  deviation, 
while  reducing  the  calibre  of  the  passage  on  one 
side,  must  enlarge  it  on  the  other,  it  is  probable 
that  the  defective  development  of  bone  asso- 
ciated with,  or  the  cause  of,  deviation  of  the 
septum  is  the  more  important  factor.  Spurs 
or  crests  are  sometimes  found  associated  with  a 
deflected  septum.  Chronic  congestion  of  the  mu- 
cous membrane  of  the  inferior  turbinate  bones 
is  sometimes  given  as  a  form  of  obstruction 
sufficient  to  induce  habitual  mouth-breathing, 
but  according  to  Tilley  (1.52)  this  condition  is 
generally  dependent  on  the  presence  of  adenoids. 

The  cause  of  adenoids  does  not  properly 
come  within  the  scope  of  this  chapter,  but  it 
is  generally  believed  that  clamp,  and  chronic 
catarrh,  are  mainly  responsible,  and  Tflley  con- 
siders that  improper  feeding  on  soft  food  is  also 
to  Ijlame.  Other  writers,  such  as  Marfan  (114) 
and  Korner  (102),  consider  that  rickets  is  the 
real  cause  and  acts  by  inducing  glandular 
hypertrophy  and  sclerosis  of  bone ;  Marfan 
holds  the  opinion  that  the  deformed  upper  arch 
frequently  associated  with  adenoids  is  directly 
caused  by  rickets.  The  evidence  is,  however, 
not  altogether  satisfactory.  Adenoids  have 
been  included  among  the  many  indications  of 
degeneracy  (100),  but  if  this  is  an  exi^lanation 
at  all  it  is  but  a  very  vague  one. 

Adenoids  develop  usually  between  the  ages 
of  about  one  and  seven  years  ;  at  a  later  period, 
after  several  harmful  consequences  have  accrued, 
they  may  become  reduced  in  size,  and  may 
almost  disappear  about  the  time  of  puberty. 
The  cardinal  symptoms  are  open  mouth  during 
sleep,  snormg,  some  degree  of  deafness,  and  a 


liability  to  repeated  "  colds  ".  In  course  of  time 
a  typical  adenoid  facies  develops,  with  narrow- 
flattened  nose,  dropped  chin,  thickened  everted 
lips,  pallid  complexion,  and  generally  dull 
appearance  (see  Fig.  120).  Other  signs  and 
symptoms  belong  to  the  more  remote  effects 
of  adenoids  on  the  growth  of  other  parts 
of  the  body,  such  as  a  flattened  chest  and 
impaired  nutrition  (see  Fig.  121).  The  view 
has  been  advanced  by  Sajous  and  elabor- 
ated by   Parke   Lewis   (133).   that  nutrition  is 


Fig.  12U. — Adenoid  faeies.     (Sir  \V.  AuiiUT.iNdT  Lane  : 
Trans.  Odont.  Soc.) 

controlled  by  the  pituitary  body,  and  that 
adenoids  may  obstruct  the  foramen  lacerum 
medium,  and  so  interfere  with  the  nervous 
connection  of  this  organ,  which  lies  in  close 
proximity. 

Other  authorities  claim  that  deficiency  of  thy- 
reoid secretion  is  responsible  alike  for  the  growth 
of  adenoids  and  the  softness  and  plasticity  of 
bone,  because  the  thyreoid  glancl  stimulates 
activity  of  w  hite  blood  corpuscles  and  controls 
fixing  of  lime  salts.  W.  R.  H.  RoUinson 
Wliitaker  (171)  supports  this  view,  and  Prof. 
Keith   says  :    "I   am   sure   there   is  a  relation 


77 


more  than  a  mechanical  one  between  face 
development  and  adenoids,  more  likely  through 
the  pituitary  body  than  through  tiie  thyreoid, 
but  probably  both."  H.  Ewan  Waller  (166) 
gives  an  excellent  account  of  the  physiology 
of  the  thyreoid  secretion,  especially  in  its  rela- 
tion to  dentistry.  He  believes  that  contracted 
arches   are   due   to   muscular   action   on   bones 


^ 


Fig.  121. — Adenoid  thorax  aji.l  atinudr.      (Sii!  W. 
Arbuthnot  L.\ne:    Trans.  Udont.  .'^oc.) 

deficient  in  lime  salts  on  account  of  thyreoid 
inactivity,  and  he  thus  eliminates  nasal  ob- 
struction as  a  causative  factor. 

The  causes  of  deflected  septum  have  not  been 
definitely  established,  but  injury  in  early  years 
is  generally  accepted  as  one  of  the  most  frequent, 
and  Mosher  (118)  has  propounded  the  view, 
also  accepted  by  Pfaff  (128),  that  the  defect 
is  commonly  associated  with  irregularity  in  the 
period  of  eruption  of  the  permanent  central 
incisors.     He    has    investigated    the    question 


with  much  care  and  in  a  large  number  of  cases, 
and  has  studied  in  detail  the  form  and  growth 
of  the  pre-maxilla.  His  views  are  as  foUoN^s  : 
The  pre-maxilla,  in  the  course  of  development, 
should  shrink  in  size  and  turn  down ;  failure 
to  do  so  i^roduces  the  negro  type  of  dentition, 
and  this  failure  is  caused  by  irregular  eruption 
of  the  permanent  incisors  or  by  uijury.  Delayed 
eruption  of  one  incisor  causes  hypertrophy  of 
the  pre-maxillary  wing  above  it ;  this  disturbs 
the  retaining  groove  of  tlie  wmgs  in  wliich  the 
tip  of  the  vomer  rests.  The  cartilaginous 
septum  slips  from  its  bed  in  the  groove  made  by 
the  two  leaves  of  the  vomer,  and  the  groove 
spreads  out,  one  side  disappearing ;  so  that  a 
spur  is  formed  along  its  upper  edge.  The 
lower  edge  of  the  cartilage  curls  upward  and 
outward  and  a  compensating  convexity  occurs 
above  the  enlarged  pre-maxillary  \\ing  and 
forms  a  short  basal  spur.  Whatever  may  be 
the  exact  cause,  the  deviation  of  the  septum 
does  not  usually  develop  till  about  seven 
years  of  age,  at  \^hich  the  central  incisors 
erupt,  and  it  may  possibly  be  regarded  as  a 
direct  consequence  of  nasal  insufficiency  due 
to  adenoids,  for  if  the  vertical  development  of 
the  air-passage  with  a  high-arched  palatal 
vault  is  sub-normal,  the  septum  may  be  forced 
to  adopt  a  sinuous  form  for  want  of  accom- 
modation. 

The  liarmful  effects  of  nasal  obstruction  by 
adenoids  or  deflected  septum  vary  considerably 
in  individuals  of  dift'erent  type.  The  size  of 
the  naso-pharynx  exhibits  a  large  range  in 
different  people  (155,  p.  337),  and  in  the  so- 
called  leptoprosopic  or  narrow  face  obstruction 
is  easily  caused  by  a  comparatively  slight  amount 
of  adenoid  hypertrophy,  said  to  be  more  frequent 
in  such  people,  or  by  a  trivial  deflection  of  the 
septum  (49) ;  whereas,  m  the  opposite  type  of 
chamaeprosopic  face  adenoids  of  moderate  size 
produce  little  ill-effect,  and  a  deflected  septum 
is  of  slight  consequence  (112)  (128)  (175).  The 
narrow  face  occurs  most  frequently  in  doli- 
chocephalic people,  so  that  the  occurrence  of 
mouth-breathing  is  to  some  extent  a  racial  char- 
acteristic (84). 

It  is  rather  curious  that  most  of  the  gross 
forms  of  abnormal  occlusion — superior  and 
inferior  protrusion  and  retrusion — may  be 
associated  with  nasal  obstruction  and  mouth- 
breathing,  although  it  should  be  recognized, 
on  the  one  hand,  that  these  forms  of  mal- 
occlusion may  occur  independently  of  mouth - 
breathing,  and  on  the  other  hand,  that  mouth- 
breathing  is  not  al\\  ays  follow  ed  by  any  obvious 
deformity  of  the  maxilla  or  mandible  or  dental 
arches  (175).  The  usual  tyiae  of  maxUla  in 
these  cases  shows  a  laterally  contracted  arch 
with  high -vaulted  palate  and  anterior  teeth 
prominent   and   mclined   forward;   it   does  not 


78 


usually  become  evident  tiU  about  six  years 
of  age  (100).  In  some  cases,  the  central  incisors 
are  rotated,  so  that  the  lingual  surfaces  approxi- 
mate, the  laterals  are  rotated  and  displaced 
lingually,  and  the  general  form  of  the  arch  is 
V-shaped  (see  Fig.  122).  In  others  the  arch  is 
more  U-shaped,  and  the  incisors,  though  pro- 
minent, are  not  rotated.  In  the  V-shaped  arch 
the  want  of  space  in  the  incisor  and  canine  region 
is  very  apparent,  the  latter  tooth  often  being 
incompletely  erupted,  whereas  in  the  U-shaped 
arch  there  is  often  spacing,  and  the  canine  sliares 
to  some  extent  in  the  prominence  and  obliquity 


Fio.  122. — Adenoid  arches.  The  maxilla  is  very  characteristic  :  note  the 
V-shaped  arch  and  the  rotation  and  displacement  of  the  incisors. 
(Norman  G.  Bennett.) 


of  the  incisors.  Brady  (35)  draws  a  sharp 
distinction  between  these  two  forms,  but  it  is 
doubtful  whether  this  can  be  upheld. 

Turner  (155,  p.  337)  appears  to  ascribe  want 
of  proper  spacing  of  the  deciduous  teeth  at 
about  five  years  of  age,  and  failure  in  vertical 
development  of  the  anterior  portions  of  the 
maxilla,  leading  later  to  "open  bite",  both 
to  adenoids ;  but  in  the  opinion  of  the  writer 
the  former  phenomenon,  at  lea.st,  occurs  quite 
frequently  with  normal  breathing,  and  is  refer- 
able to  want  of  development  from  other  causes. 
ThLs  is  discussed  more  fully  later. 

It  is  a  moot  point  whether  the  summit  of  the 


palatal  vault  is  really  higher  than  normal  or 
not  (130)  (175),  or  whether  it  only  appears 
to  be  so  by  reason  of  the  buccal  teeth  and 
alveolus  being  more  vertical  than  is  normally 
the  case,  and  more  closely  approximated ;  but 
it  is  probable  that  owing  to  nasal  insufficiency 
a  proper  downward  growth  of  the  palate  ha.s 
not  been  mduced.  Brady  points  out  that 
protrusion  is  favoured  by  shortness  of  the  upper 
lip  occasioned  by  faulty  nasal  development, 
and  Turner  (155,  p.  337)  also  emphasizes  the 
influence  of  the  length  of  the  upper  lip  in 
determining  whether  the  anterior  teetli  shall 
protrude  or  be  deflected  back- 
wards, and  thereby  augment 
irregularity  in  position  of  the 
buccal  teeth.  It  is  generally 
agreed  that  the  form  of  the 
lower  arch  is  not  directly 
affected  by  adenoids,  but 
Kohler  (100)  considers  that  the 
rate  of  alteration  in  the  angle 
is  diminished ;  and  in  cases  of 
post-normal  occlusion  of  the 
lower  teeth  there  must  almost 
of  necessity  be  a  failure  in 
backward  growth,  and  probably 
a  correlated  change  in  the 
ascending  ramus  and  articula- 
tion. 

Although  the  deformities  of 
tlte  dental  arches  associated 
with  mouth-breathing  are  so 
generally  recognized,  there  is 
a  remarkable  divergence  of 
opinion  as  to  the  exact  manner 
in  which  the  changes  are 
brought  about.  Perhaps  the 
most  commonly  accepted  view 
is  that  the  open  condition  of 
mouth  produces  tension  in  the 
muscular  tissue  of  the  cheeks, 
and  a  slight  approximation  of 
the  two  sides,  and  that  thereby 
pressure  is  brought  to  bear  on 
the  buccal  surfaces  of  the  upper 
arch.  Distinction  is  drawn  by 
different  writers  between  tissue  tension  and 
muscle  tension,  the  former  being  simply  a  passive 
stretching,  and  the  latter  involving  the'  active  use 
of  the  muscles.  Confirmation  of  the  latter  view 
is  to  be  found.^  the  description  of  a  case  by 
Lambert  Lack^n  wliich  facial  paralysis  had 
occurred  at  two  years  of  age ;  as  a  result  of 
adenoids,  and  mouth-breathing  contraction  of 
the  arch  occurred  only  on  the  healthy  side. 
Kohler  (100)  attaches  special  importance  to 
the  action  of  the  muscles  in  mastication.  Asso- 
ciated with  this  increased  pressure  from  with- 
out, there  mu.st  be  a  diminished  pressure  from 
within  by  the  tongue;  in  normal  nasal  breathing, 


79 


with  the  mouth  closed,  the  tongue  is  firmly 
pressed  against  the  palate ;  but  even  a  slightly 
open  mouth  reduces  this  pressure  or  removes 
the  tongue  from  the  palate  entirely  (84)  (112) 
(152)  (155,  p.  337). 

The  influence  of  the  normal  tongue  in  expand- 
ing the  arches  finds  some  corroboration  in  the 
peculiar  formation  associated  with  hypertrophy 
of  the  tongue.  In  the  case  of  cretins  the  tongue 
is  usually  much  enlarged,  and  the  dental  arches 
are  also  large  and  widely  spread.  Increase  m 
size  of  the  tongue  from  other  diseases,  such 
as  new  growtlis,  if  of  sufficient  duration  usually 
causes  modification  of  the  dental  arches.  The 
question  of  the  relationship  between  diminished 
size  of  the  tongue  and  contracted  arches  has 
already  been  referred  to  and  A\ill  be  further 
considered. 

Other  writers   reject  the  cheek  theory,  and 
believe  that  the  explanation  is  to  be  found  in 
alterations  in  atmospheric  pressure  above  and 
below  the  vault  of  the  palate.     This  view  finds 
different    methods    of    expression    by    various 
authors,  but  the  effects  described  are  not  very 
difl^erent.     Mayo  Collier   (50)   found,   by  intro- 
ducing  a  manometer  into  the   nose,   that  the 
air-pressure  was  increased  at  each  respiration, 
and  he  cites  the  experiments  of  Ziem  on  animals, 
in  which  blocking  of  one  nostril  caused  defective 
development,  not  only  of  the   maxilla  on  that 
side,  but    also    of    most    of    the    other    bones 
of  the  face  and  anterior  part  of  the  cranium. 
Sir  W.  Arbuthnot  Lane  (7)  takes  the  same  view, 
and  further  points  out  that  the  lack  of   intra- 
nasal pressure  is  antedated  by  a  dimmished  vital 
capacity   of   the   lungs,    whereby   the   effect    is 
augmented.     Metzger    (178)    has    pomted    out 
that  the   mouth   can   be   kept   closed  for  long 
periods  without  fatigue,  but  that  the  muscles 
soon  tire  if  it  is  slightly  open.     He  concludes 
that    muscular    equilibrium    is    not    the    sole 
means  by  which  the  mouth  Ls  kept  easily  closed, 
but  that  the  mandible  is  really  slung  to  the 
palate  by  suction,  the  tongue  completely  closing 
the   oral  cavity ;   that   is   to  say,   atmospheric 
pressure    from    \sithout    partly    supports    the 
mandible.     Donders     (178)     corroborated    this 
view  by  introducing  a  small  manometer,  and 
demonstrating  the  existence  of  a  small  suetion- 
ciiamber    between    the    centre    of    the    dorsum 
of  the   tongue   and   the   junction   of  the   hard 
and  soft  palates,  and  another  anteriorly  between 
the  lower  surface  of  the  tongue  and  the  floor 
of  the  mouth  and  lips ;  the  latter,  he  says,  is 
only    produced    when    the    tongue    is    drawii 
backwards  or  downwards.     It  Ls  clear  that  in 
mouth-breathuig    the    downward    pull    on    the 
vault    of   the    palate    would    be    absent.     This 
theory,    briefly   stated,   sounds   somewhat   fan- 
tastic, but  it  is  probable  that  something  of  the 
kind  really  exists,  and  may  be  an  important 


factor  in  the  downward  growth  of  the  palate. 
Donders  well  points  out  that  a  very  powerful 
suction  is  recognized  as  retaining  the  head  of 
the  femur  in  the  acetabulum  of  the  hip-joint. 
Emil  Herbst  (89)  has  experimented  on  similar 
lines.  He  corroborates  the  findings  of  Metzger 
in  the  main,  but  disagrees  with  Donders  in  his  dis- 
crimination between  an  anterior  and  a  posterior 
space.  He  believes  that  the  action  of  the  tongue 
in  producing  them  is  supplemented  by  move- 
ment of  the  mandible.  He  goes  so  far  as  to 
ascribe  the  development  of  polypi  of  the  gum 
or  pulp,  and  lengthening  of  unopposed  teeth,  and 
enlargement  of  the  maxillary  sums  under  suni- 
lar  conditions,  to  "suction"".  Herbst"s  paper 
contams  references  to  most  of  the  publications 
by  German  writers  on  this  subject.  Some 
writers  (1)  (84)  content  themselves  with  pointmg 
out  that  the  palate  fafls  to  develop  and  expand 
because  the  proper  air-passages  within  are  not 
used,  on  the  general  prmciple  that  function 
is  necessary  for  growth.  It  may  be  that  this 
is  no  real  explanation  at  all,  but  although  it 
offers  no  clue  as  to  the  exact  mechanism,  it 
emphasizes  the  important  biological  principle 
that  deficiency  is  to  be  expected  from  disuse, 
and  that  it  is  not  essential  to  seek  explanation 
i  in  adventitious  external  forces. 

One  other  possible  factor  must  be  remembered. 
Under  normal  conditions  the  occlusion  of  the 
teeth    probably    affords    considerable    stimulus 
to  growth,  and  tends  to  retain  a  proper  degree 
of  shallowness  of  the  vault  of  the  palate.     When 
the  mouth  is  kejrt  constantly  open,  the  upper 
buccal    teeth    tend    to    grow    dowiiwards    and 
inw-ards,   and  so  produce   depth   of  vault   and 
parallelism  of  the  sides  of  the  arch  (100)  (175). 
The    question    arises,    to    what    extent    me- 
chanical expansion  of  the  maxillary  arch  will 
affect  parts  other  than  the  alveolus,  and  bring 
about  a  widening  of  the  nasal  passages.     In  the 
case  of  patients   whose  adenoids  have  not  been 
removed,  but  have  become  reduced  in  size  in 
course    of    years,    the    more    recently    formed 
portions   of  the   arch   are   more   nearly   of  the 
normal    width — the   second   permanent   molars 
erupt  in  a  wider  arch  than  that  of  the  other 
buccal    teeth.     It    is    obvious,    therefore,    that 
removal   of  adenoids   is   imperatively  required 
at  an  early  age  to  allow  of  subsequent  develop- 
ment   proceeding    on    normal    lines ;    to    what 
extent  improvement  takes  place  in  the  parts 
already   formed   is   not   certain,    but   probably 
it  is  very  little  in  the  absence  of  mechanical 
treatment.     According  to  Turner  (155,  p.  337) 
the  power  of  increase  of  size  in  the  anterior 
portion  of  the  arch  is  lost  after  about  twelve 
years  of  age. 

It  must  be  remembered  that  after  removal 

of     adenoids    the    acquired    habit    of    mouth - 

,  breathing  is   sometimes   retained,  and   further- 


80 


more  that  want  of  development  of  the  nasal 
passages,  with  or  without  deviation  of  the 
septum,  may  be  such  as  to  offer  very  little 
inducement    for   normal    breathing.     In    these 


Fig.    123. — Characteristic    deciduous 
children.     Left,    child    aged    4i 
aged  5  years.     (G.  Noethcroft  ; 
Dental  Review.) 


ai-clu'S  in  bottle-fed 
years ;  right,  cliild 
Dental  Record  :  from 


eases  there  is  very  little  doubt  that  mechanical 
expansion  widens  the  nasal  air-way ;  accord- 
mg  to  Pfaff  (128)  there  is  actually  a  lowering 
of  the  vault  of  the  palate  if  the  operation  is 
conducted  suflficiently  slo\\ly,  but  Feder.spiel 
(73)  in  a  recent  article  denies  this.  Mosher  ( HB) 
and  Black  (27)  affirm  the  efficacy  of  such 
means  for  the  treatment  of  deflected  septum. 
In  an  interesting  article,  C.  A.  Hawley  (86) 
illustrates  cases  to  show  that  there  is,  as  a  rule, 
little  or  no  natural  expansion  of  the  arch  after 
removal  of  adenoids,  but  that  artificial  ex- 
pansion produces  a  profound  effect  on  the 
general  development  of  the  face. 

The  question  of  «hat  really  happens  under 
mechanical  treatment  for  maxillary  expansion 
— whether  the  alveolus  only  is  bent  outwards 
(or  absorbed  and  redeposited),  or  whether 
there  is  actually  separation  follo\\ed  by  deposit 
at  the  median  suture — i.s  discussed  under 
'■  Physiology  of  Tooth  Movement  " ;  but  if,  as 
seems  often  to  be  the  case,  nasal  inefficiency  is 
remedied,  the  latter  process  must  apparently 
occur,  and  it  is  probable  that  the  effect 
produced  depends  largely  on  the  method 
employed. 

The  effects  of  artificial  feeding  of  infants  on 
jaw-formation  has  been  much  discussed.  It 
has  been  pointed  out  that  the  ordinary  rubl)er 
teat  dift'ers  so  much  from  the  natural  organ  that 
unnatural  methods  of  taking  in  the  milk  are 
engendered  in  the  infant.  In  natural  feeding 
the  whole  of  the  nipple  and  part  of  the  breast 
are  firmly  grasped  by  the  infant,  and  the  milk 
is  mainly  obtained  by  alternate  acts  of  com- 


pression and  release,  in  a  manner  analogous 
to  that  adopted  in  cow-milking ;  it  is  said  that 
suction  plays  little  or  no  part  in  the  process. 
The  rubber  teat,  on  the  other  hand,  is  smaller 
and  much  less  solid  and  more  compressible, 
and  the  infant  has  to  a  great  extent  to  suck 
the  milk  out  of  the  bottle ;  in  this  ■\\'ay  the 
cheek  muscles  are  brought  into  play  and 
pressure  is  broutrht  to  bear  on  the  maxilla. 
It  is  urged  that  lateral  compression  and 
anterior  prolongation  are  induced  in  this 
manner,  and  that  the  effect  is  exhibited  ev^en 
in  the  permanent  dentition.  G.  Northcroft 
(122),  who  has  studied  with  much  care  the 
development  of  the  jaws  in  early  years,  finds 
a  remarkable  similarity  in  the  type  of 
deciduous  arch  (with  in-standing  laterals  and 
centrals  in  malalignment)  in  many  bottle- 
fed  children  (see  Figs.  123.  124).  f.  Pedley 
(127)  is  a  strong  advocate  for  thi.s  view,  and 
Colyer  (55)  has  published  diagrams  showing 
the  association  of  abnormal  forms  of  palate 
with  bottle-feeding.  The  cases  cited  by 
Pedley  are,  however,  exceptional,  inasmuch 
as  artificial  feeding  with  the  rubber  teat  was 
continued  for  prolonged  periods  up  to  two 
and  three  years  of  age.  In  the  ordinary  course 
bottle-feeding  is,  or  should  be,  abated  con- 
siderably at  nine  to  twelve  months  and  aban- 
doned   altogether    as    soon    after    as    possible. 


Fig.  124. — The  same  in  occlusion.  Upper  figure 
corresponds  with  the  left-hand  figure  of  123; 
lower  figure  with  right-hand  figure.  Note  the 
occlusion — normal  in  the  upper  figure,  post- 
normal  in  the  lower.  (CJ.  Northcroft  :  Dental 
Record  ;  from  Dental  Review.) 

Harm  jirobably  results  when  artificial  adminis- 
tration of  milk  is  badly  managed  and  unduly 
prolonged,  especially  if  imperfect  apparatus 
is  employed  ;  much  importance  attaches  to  the 
size  of  the  orifice  in  the  teat,  and  the  regula- 


81 


tion  of  the  flow  by  providing  for  ingress  of 
air  at  the  opposite  end  of  tiie  bottle.  If  these 
are  so  adjusted  that  the  infant  takes  its  meal 
in  about  the  same  time,  twenty  minutes, 
as  it  would  in  a  natural  way,  the  risks  are 
minimized.  Within  recent  years  rubber  teats 
liave  been  introduced  to  resemble  the  human 
breast.  In  the  opinion  of  the  writer  the  evils 
of  artificial  feeding  have  been  greatly  exagger- 
ated, and  he  believes  that  if  proper  care  is  taken 
no  evil  effects  on  maxillary  development  need 
accrue.  McKenzie  (112)  (113)  is  of  opinion 
that  the  more  gross  deformities  of  the  maxillae 
cannot  be  produced  in  this  way. 

The  constant  u.se  of  the  "  baby  comforter", 
whether  solid  or  perforated,  is  quite  a  different 
matter.  This  is  used  for  an  unnatural  purpose 
for  prolonged  periods,  and  should  be  con- 
demned ;  the  desire  for  it  by  the  infant  is  very 
much  a  matter  of  habit,  and  acquiescence  by 
the  mother  or  nurse  is  an  indication  of  lazi- 
ness. Its  only  merit  is  that  it  jjractically  com- 
pels nasal  breathing,  which,  however,  is  not  an 
acquired  art,  but  a  natural  instinct  on  the  part 
of  a  healthy  infant  free  from  malformation 
and  disease. 


J.  F.  CoJyer  is  of  opinion  that  serious  defects 
of  development  are  to  be  ascribed  to  the  use  of 
the  '■  baby  comforter  ".  He  considers  that  the 
arches  are  flattened,  and  that  the  upper  arch  is 
drawn  forward,  and  that  the  type  of  superior 
protrusion  described  on  p.  128  [Class  III  (2)  (c)] 
is  so  produced.  Colyer  includes  in  this  class 
many  of  the  cases  described  as  Inferior  Retru- 
sion  by  the  writer. 

Injuries,  such  as  fracture  of  the  bones,  or 
cicatrices  from  burns,  will  of  course  produce 
abnormalities  in  the  position  of  the  teeth. 
J.  F.  Colyer  has  described  t«o  marked 
examples  of  post-normal  mandible  that  he 
considers  were  due  to  injury  at  birth  during 
prolonged  face  presentation  {Dental  Record, 
Feb.  1914,  p.  100). 

One  other  jJathological  condition  must  be 
mentioned.  Cryer  (60)  believes  that  excessive 
calcification  of  bone  occurs  sometimes  in 
patients  of  a  gouty  or  rheumatic  diathesis,  and 
that  under  certain  condition.s  this  may  cause 
the  contained  teeth  to  adopt  abnormal  posi- 
tions, or  may  prevent  normal  eruption.  In 
another  paper  Cryer  (61)  discusses  some  other 
minor  pathological  causes. 


CHAPTER  V 


ABNORMALITIES  OF  POSITION  (continued) 


Part  III 

Classification  of  Abnormalities,  Consideration  of 
the  Different  Types,  their  Causation,  and  the 
Principles  of  their  Treatment 

Classification  of  abnormalities  may  be  based 
on  a  consideration  of  the  tooth  or  teeth  affected, 
and  the  bones  involved,  and  the  nature  of  the 
deviation  from  the  normal — that  is  to  say,  on 
pathology — or  on  the  aetiology  of  the  various 
conditions.  Great  difficulties  at  once  present 
themselves  in  either  case  ;  the  diversity  among 
abnormalities  is  considerable,  and  the  nature 
of  them  is  as  a  rule  very  complex,  only  a  small 
number  consisting  of  a  simple  deviation  arismg 
from  a  direct  and  obvious  cause,  so  that  even 
though  well -recognized  type-forms  only  are 
selected,  it  is  difficult  to  classify  them  on  any 
useful  basis  by  which  the  relation  of  one  form  to 
another  may  be  shown,  and  it  is  still  more 
difficult  to  relegate  the  more  complex  forms, 
exhibiting  a  combination  of  different  kinds  of 
abnormality,  to  their  appointed  place.  Of  the 
simple  forms  the  immediate  cause  is  usually 
recognized  and  known,  but  as  regards  the  more 
complex  forms,  especially  those  clearly  involving 
some  error  of  bony  development,  causation  is 
for  the  most  part  imperfectly  unr^rurtood  ;  the 
immediate  origin  of  some  of  them  I'ect  be  fairly 
obvious,  but  the  real  first  origo  ;  is  far  to 
seek.  On  the  one  hand,  the  saic^pensin  cause 
operating  in  different  individuals^y  exporoduce 
quite  different  results,  probably  >it  out«unt  of 
differences  in  the  adventitious  or  «libuting 
causes ;  and  on  the  other  hand,  •!  biases  that 
appear  to  be  identical  or  nearly  so';  may  be  and 
often  are  due  to  quite  different  causes,  and  are 
indeed  inherently  and  pathologically  different, 
and  require  treatment  on  different  principles. 
For  example  the  kinds  of  deformity  that  used 
to  be  known  generally  as  superior  protrusion 
are  now  more  fully  understood,  and  it  has 
become  clear  that  at  least  four  types  totally 
different  in  their  aetiology  and  pathology  were 
included  under  that  title ;  in  the  classification 
shortly  to  be  outlined  these  types  will  be  dis- 
tinguished from  one  another.  It  is  probable 
.,  that  in  tlie  development  of  the  lower  part  of 
^Ahe  face,  the  nasal  cavities,  the  jaws  and  teeth, 
hiore  complex  and  subtle  changes  occur  in 
j  Towth   from   infancy   to   adolescence   than   in 


any  other  part  of  the  body ;  and  furthermore 
these  changes  or  their  results  are  often  the 
vehicle  of  hereditary  transmission  as  to  form 
and  structure,  and  are  very  markedly  the  play- 
thing of  influences  of  environment,  such  as  diet. 
It  is  therefore  not  to  be  wondered  at  that  when 
so  many  possibilities  of  error  in  development 
exist,  diversity  of  form  should  be  so  great,  and 
that  whereas  hi  the  normal  process  so  many 
influences  contribute  to  a  perfect  result,  a 
small  deviation  in  one  particular  may  throw  the 
whole  sequence  out  of  gear  and  originate  a 
deformity  of  a  magnitude  out  of  all  proportion 
to  the  original  cause.  It  may  be  said,  then,  that 
the  processes  of  growth  and  development  of  the 
teeth  and  the  associated  parts  are  subject  to 
much  variation,  and  are  particularly  susceptible 
to  external  stimulus  in  the  form  of  modified 
function  of  the  mouth  and  nose,  and  that  they 
are  intimately  connected  with,  and  mutually 
dependent  upon,  one  another.  Defects  in  the 
process  lead  to  such  diversified  forms  of  abnor- 
mal development  that  not  only  is  it  difficult 
to  trace  the  exact  causes,  but  even  the  precise 
diagnosis  of  the  exact  conditions  is  in  many 
cases  far  from  easy. 

Study  of  the  aetiology  and  pathology  is,  how- 
ever, only  useful  in  so  far  as  it  indicates  rational 
lines  for  preventive  and  remedial  treatment. 
Surgical  or  mechanical  interference  depends 
for  its  success  on  a  knowledge  of  causation, 
and  until  investigation  has  provided  a  more 
perfect  equipment  of  that  kind  treatment  must 
remain  largely  empirical.  Ingenuity  of  con- 
trivance cannot  compensate  for  lack  of  know- 
ledge, and  to  this  fact  must  be  attributed  the» 
want  of  uniformity  of  success  with  different 
cases,  even  in  the  hands  of  the  most  skilful 
operators.  It  should  be  recognized  that  the 
liability  l'"^  a  deformity  that  has  apparently 
been  fulP^^wrected  to  recur,  even  after  time 
has  been  allowed  for  deposit  of  new  bone 
around  the  ro  i|r  of  translated  teeth,  depends 
upon  one  of  t  j'  things  :  either  the  correction 
is  apparent  rather  than  real  and  is  incomplete 
in  itself,  or  the  causes  that  produced  the 
deformity  continue  to  operate.  Such  causes 
may  or  may  not  be  remediable,  but  further 
acquisition  of  knowledge  will  certainly  show  what 
are  the  possibUities  of  permanent  improvement, 
and  also  establish  the  principles  of  prevention 
and  early  treatment. 

82 


/ 


83 

On  these  grounds  it  has  seemed  best  to  attempt  ]  of  individual  teeth,  whether  of  one  or  more, 

to  classify  abnormalities  of  position  primarily  in   which  the  cause  of   the  displacement  acts 

on  an  aetiological  basis  into  three  classes,  and  directly,  or  nearly  directly,  on  the  teeth  them- 

then    to    discuss    the    several    forms   occurring  !  selves,  and  any   bony  abnormality  that  there 


under  these  heads,  and  to  define  the  pathological 
condition,     and    the    immediate    and    remote 


may    be    is    secondary :     in    the    second    and 
third  classes,   on    tlie  other  hand,  the    imme- 


causes,  and  the  consequent  principles  of  treat-  i  diate  cause  of  dental  malposition  is  defective 
ment,  as  far  as  the  present  state  of  knowledge  |  bony  development,  wliich  is  itself  the  outcome 
permits.  It  may  at  once  be  said  that  the  first  j  of  more  remote  causes,  whether  genetic  or 
class    is    mainly    concerned    with    malposition   |  environmental. 

CLASSIFICATION 

I. — Abnormal  position  of  one  or  more  teeth  due  to  local  causes. 

(1)  Retained  deciduous  teeth. 

(2)  Teeth  of  abnormal  form. 

(3)  Supernumeraries. 

(4)  Absent  teeth. 

(5)  Abnormal  fraenum  labii. 

(G)  Position  of  crypt,  and  total  displacement. 

(7)  Thumb  or  finger  sucking — 

Superior  proclination. 
Inferior  retroclination. 
Open  bite. 

(8)  Premature  loss  of  deciduous  or  permanent  teeth. 

Deciduous  incLsors. 
Deciduous  canines. 
First  deciduous  molars. 

Second  deciduous  molars — forward  translation  or  inclination  of  first  permanent 
molars. 

Buccal  or  lingual  inclination  of  canines. 

Buccal  or  lingual  inclination  of  premolars. 

Rotation  of  upper  incisors. 

Imbrication  of  lower  incisors. 
First  permanent  molars. 

Close  bite  and  secondary  superior  proclination,  or  secondary  inferior  retro- 
clination. 

Backward  translation  or  inclination  of  premolars. 

Deviation  of  centre. 
Other  permanent  teeth. 

II. — Abnormal  formation  of  a  part  or  the  whole  of  either  arch  due  to  developmental  defects  of  bone. 

(1)  Conditions  first  showing  themselves  while  deciduous  molars  are  still  in  place. 

Rotation  or  postplacement  of  upper  incisors. 
Imbrication  or  "  fanning  "'  of  lower  mcLsors. 

(2)  Conditions  arising  or  further  developing  after  loss  of  deciduous  molars. 

Buccal  or  lingual  inclination  of  canines. 

Buccal  or  lingual  inclination  of  premolars. 

Accentuation  of  rotation  of  upper  incisors,  or  of  imbrication  of  lower  incisors. 

(Lingual  incHnation  of  posterior  teeth.) 

III. — ^Abnormal  relationship  between  the  upper  and  lower  arches,  and  between  either  arch  and 
the  facial  contour,  and  correlated  abnormal  formation  of  either  arch,  due  to  developmental 
defects  of  bone. 

(1)  Vertical. 

(o)  Open  bite. 
(6)  Close  bite. 

Secondary  superior  proclination. 


84 


(2)  Antero-posterior  (pre-normal  or  post-normal  occlusion  of  upper  or  lower  arch). 

(a)  Normal  or  sub-normal. 

(b)  Inferior  retrusion. 

Inferior  retrognathism. 

Secondary  superior  proclination. 
Secondary  superior  retroclination. 

(c)  Superior  protrusion. 

Superior  dental  preplacement  or  proclination. 

Superior  prognathism. 
((/)  Inferior  protrusion. 

Inferior  prognathism. 
(e)  Superior  retrusion. 

Superior  retrognathism. 
(/)  Double  protrusion. 

Superior  and  inferior  dental  preplacement  or  proclination. 

Superior  and  inferior  prognathism. 
(g)  Double  retrusion. 

Superior  and  inferior  dental  postplacement  or  retroclination. 

Superior  and  inferior  retrognathism. 

(3)  Lateral. 

Labial  or  lingual  occlusion  of  upper  or  lower  posterior  teeth  on  one  side  or  both. 


CLASS  I. — Abnormal  Position  of  One  or  More 
Teeth  due  to  Local  Causes 

1.  Retained  Deciduous  Teeth. — In  some  cases 
the  absorption  of  the  roots  and  the  shedding 
of  the  crowns  of  the  deciduous  teeth  are  delayed 
beyond  the  normal  periods,  possibly  because  of 
the  tardy  development  of  the  permanent  suc- 
cessors. If,  however,  the  process  of  shedding, 
even  though  delayed,  follows  an  orderly  course, 
no  irregularity  of  the  kind  under  consideration 
is  likely  to  ensue.  It  is  where  single  teeth  are 
retained  tliat  tlie  ultimate  position  of  the  per- 


FiG.  125. — Retained  right  deciduou.s  central,  inierupted  permanent 
central,  rotated  permanent  lateral,  and  flattened  arch.'  (Norman 
G.  Bennett.) 


nianent  successor  is  affected,  and  the  offending 
tooth  or  root  is  nearly  always  one  in  which 
death  of  the  pulp  has  supervened  on  caries  or 
injury.  The  normal  process  of  absorption  is 
interfered  with,  if  not  inhibited,  under  these 
circumstances,  and  even  a  single  root  of  a 
molar  will  retain  its  hold  sometimes  for  a  con- 
siderable time.  Less  frequently,  the  absorption 
of  the  roots  of  a  deciduous  tooth  is  imperfect 

^  A  radiograph  has  shown  the  presence  of  an  un- 
erupted  snpernnmerarj-  tooth  impeding  the  eruption 
of  the  permanent  central  incisor. 


because  of  a  slight  deviation  from  the  normal 
in  the  Ime  of  eruption,  or  the  position  of  the 
crypt,  of  the  succeeding  permanent  tooth  ;  in 
such  cases  only  the  portion  of  the  root  or  roots 
directly  impinged  upon  will  be  absorbed  by 
the  intervening  osteoclasts.  The  commonest 
example  of  this  is  .seen  in  the  upper  molars, 
where  a  somewhat  widely  divergent  palatine 
root  may  be  only  hollowed  out  on  its  buccal 
aspect  and  serve  to  retain  the  crown  in  position. 
It  is  remarkable  to  what  extent  a  tooth  may 
be  deflected  from  its  course  during  eruption 
by  a  small  piece  of  loose  root,  the 
direction  of  the  deflection  being 
usually,  but  not  always,  determined 
by  the  normal  j)ositioii  of  the  crypts 
and  line  of  approach.  For  example, 
the  upper  incisors  erupt  on  the  buccal 
aspect  and  the  lower  on  the  lingual ; 
ia  the  case  of  an  upper  tooth  the  evil 
may  be  increased  by  interposition  of 
the  lower  lip.  If  the  deciduous  tooth 
is  shed  or  removed  sufficiently  soon, 
before  the  adjacent  permanent  teeth 
are  fully  erupted,  natural  forces, 
namely  the  pressure  of  the  lips  and 
tongue,  will  probably  correct  the 
,  but  if  it  is  retained  beyond  that 
period,  the  adjacent  teeth  will  move  into  contact 
with  the  relatively  small  deciduous  tooth  and 
encroach  on  the  space  that  should  have  been  filled 
by  the  permanent  successor,  and  thereby  prevent 
correction  by  natural  force.  An  upper  tooth 
outside  the  lower  lip  or  in  lingual  occlusion  with 
the  lower,  and  a  lower  tooth  in  labial  or  buccal 
occlusion,  will  not  be  corrected  naturallv  (155, 
p.  337).     (See  Figs.  125,  126,  127,  128,  201.) 

Treatment  in  either  event  consists  in  removal 
of  the  offending  tooth  or  root,  and  if  necessarj' 


deformity 


85 


n  the  restoration  of  space  by  correcting  the 
position  of  the  adjacent  teeth,  and  the  transla- 
tion of  the  misplaced  tooth.  Treatment 
should  be  undertaken  at  once,  because 
the  tooth  is  more  easily  moved  while 
the  root  is  incomplete,  and  consequent 
misplacement  of  other  teeth  is  avoided. 
Retention  for  two  or  three  months  is 
usually  sufficient.  It  should  be  remem- 
bered, however,  that  delayed  sheddini; 
of  a  sound  deciduous  tooth  is  prima  facie 
evidence  of  possible  abnormality  in  the 
jjosition  of  the  erupting  successor.  In 
some  cases  [see  I  (6)]  this  abnormality 
is  of  such  a  character  that  eruption  in  a  normal 
direction  is  impossible  even  with  artificial  assist- 


the  best  indication  as  to  the  correct  treatment 
to  be  pursued. 


Fig.  121). — Retained  deciduous  canines,  left  per- 
manent canine  lingual  to  arch.  (Norman  G. 
Bennett.) 


Fig.   127. — Retained  left  Imver  deciduous  canine,  permanent 
canine  distal  to  it.     (Ger.\ld  H.\rborovv.) 


ance,  and  the  deciduous  tooth  if  allowed  to 
remain  will  retain  its  place  with  the  permanent 
teeth   for   many   years.     A  radiograph  affords 


Flu.  12S. — Retained  crown  of  first  left  lower  deciduous 
molar,  premolar  displaced  buccally  and  in  buccal 
occlusion  with  iijjper  premolar.  (Norm,\n  G. 
Bennett.) 

In  cases  where  a  retained  deciduous  tooth  has 
prevented  the  eruption  of  its  successor,  rather 
than  deflected  the  latter  from  its  course, 
«hile  the  adjacent  teeth  have  encroached 
on  the  normal  space,  the  permanent  tooth 
may,  after  the  loss  of  the  deciduous  tooth, 
And  its  way  into  normal  alignment,  but 
with  some  degree  of  axial  rotation.  That 
is  to  say.  the  tooth  becomes  turned  so  that 
a  smaller  diameter  may  intervene  bet\\een 
the  adjacent  teeth  in  the  restricted  sjmce. 
This  may  occur  with  incisors  or  canines. 
Treatment  should  be  undertaken  at  once, 
the  space  restored,  and  the  abnormality 
corrected . 

2.  Teeth  of  Abnormal  Form. — An  abnor- 
mally shaped  tooth  may  give  rise  to 
deformity  in  various  ways.  If  it  is  of 
excessive  size  it  may  fail  to  erupt  com- 
pletely or  in  normal  alignment,  or  if  it 
does  completely  erupt  may  usurp  an  undue 
amount  of  simce.  If,  on  the  other  hand, 
it  is  small,  it  will  permit  movement  of 
the  adjacent  teeth  and  interfere  with 
perfect  occlusion,  and  possibly  cause  lateral 
deviation  of  the  central  incisors  from  the  median 
plane. 


86 


Treatment. — In  the  case  of  slight  abnormality 
the    tooth    should    be    brought    into    position. 


Fig.   129. — Displacement,  of  left  upper  central  incisor 
by  supernumerary.     (Norm.^n  G.  Bennett.) 

When  the  crown  of  the  tooth  is  grossly  mal- 
formed, but  the  root  (as  sho\ni  by  a  radiograph) 
is  normal  or  nearly  normal, 
the  tooth  .should  be  brought 
into  position,  and  after  a 
period  of  quiescence  an  arti- 
ficial crown  should  be  fixed. 
When  both  crown  and  root 
are  grossly  malformed  the 
tooth  should  be  extracted, 
and  the  space  allowed  to 
close  or  an  artificial  substi- 
tute (fixed  or  removable) 
inserted. 

3.  Supernumeraries. 
Supernumerary  or  supple- 
mental teeth  (see  Chapter 
III)  sometimes  erupt  ex- 
ternal or  internal  to  the  arch, 
and  sometimes  in  alignment 
with  the  other  teeth  in  the 
arch.  In  the  former  case 
extraction  is,  of  course,  the 
only  treatment  required.  In 
the  latter  case  one  or  more 
of  the  other  teeth  must  have 
been  displaced  ;  they  may  be 
in  normal  alignment,  but 
rotated  or  separated  by  the 
intrusive  tooth,  or  be  alto- 
gether prevented  from  taking 
their  place  in  the  arch. 
Supernumerary  teeth  most 
frequently  occur  in  the  upper 
incisor  region,  and  probably 
the  commonest  site  is  be- 
tween the  central  incisors 
(see  Figs.  129,  130). 

Treatment.  —  Supernume- 
rary and  supplemental  teeth  should  be  extracted, 
and  in  some  cases  natural  forces  will  I)rin2  the 


other  teeth  into  correct  position  ;  in  other  cases 
these  must  be  corrected  l)y  artificial  means. 
Doubt  \\ill  sometimes  arise  in  diagnosing  between 
a  supernumerary  tooth  and  a  lateral  incisor,  but 
a  radiograph  w  ill  usually  solve  the  difficulty. 

4.  Absent  Teeth. — Absence  of  teeth,  such  as 
the  lateral  incisors  or  the  premolars,  usually 
induces  dimimition  of  the  size  of  the  arch  and 
abnormality  of  occlusion  (see  Figs.  131.  132, 
133,  134). 

Treatment  is  not  usually  desirable  or  bene- 
ficial beyond  such  correction  of  occlusion  as 
may  be  possible.  Some  writers  recommend 
that  the  space  proper  to  the  absent  tooth  be 
preserved  or  restored,  and  an  artificial  sub- 
stitute inserted.  In  the  case  of  the  lateral 
incisors  the  deformity  is  not  usually  sufficiently 
serious,  or  the  effect  on  occlusion  great  enough 
to  justify  this  course. 

5.  Abnormal  Fraenum  Labii. — The  fraenum  of 
the  upper  lip  is  usually  attached  to,  and  blends 
with,  the  gum  on  the  labial  side  of  the  teeth. 


Fig.    130. — Displacement   of    left    upper    central    and     lateral    incisors,    two 
unerupted  supernumeraries  behind  centrals.     (Harold  Chapman.) 

but  in  a  few  cases  it  passes  between  the  central 
incisors  and  blends  w  ith  the  gum  of  the  palate. 


The  necessary  result  is  separation,  usually 
accompanied  with  slight  rotation  of  the  central 
incisors  (see  Fig.  135). 

Treatment. — It  is  some- 
times recommended  that  the 
portion  of  the  fraenum  pass- 
ing between  the  teeth  should 
be  excised,  but  it  is  usually 
sufficient  to  divide  it.  A 
very  narrow  scalpel  should 
be  used,  and  it  is  essential 
that  the  division  should  be 
complete  between  the  two 
teeth  and  carried  down  to 
the  alveolus ;  some  operators 
use  the  electro-cautery  either 
instead  of,  or  in  addition  to, 
the  scalpel.  The  movement 
of  the  lip  will  generally  pre- 
vent   reunion.      When     the 


be  corrected  before  the  eruption  of  the  laterals ; 
and  in  all  cases  treated  late  mechanical  assistance 
is   also  necessary.     The   writer  has  experience 


Flu.  131. — Absence  of  lateral  incisors,  retained  decidu- 
ous canines,  lingual  displacement  of  right  permanent 
canine.     (N.  H.  Ketti.kwell.) 


Fig.  132. — Absence  of  left  lateral  incisor,  lingual 
displacement  of  permanent  canine,  forward  move- 
ment of  posterior  teeth.     (G.  Northcroft.) 


separation  is  slight,  and  the  fraenum  is  divided 
before  the  eruption  of  the  canmes,  mechanical 
treatment  is  usually  unnecessary,  because  the 
erupting  canuies  force  the  incisors  together ; 
but  if  the  separation  is  wide  the  teeth  should 


tin.  133. — Retained  deciduous  canines,  absence  of  right  permanent  lateral 
incisor.  Left-liand  figure  shows  right  deciduous  lateral  still  in  position  ; 
right-liand  figure  shows  a  later  condition  with  permanent  canine  erupting 
against  central.     {G.  Northcroft.) 

of  a  case  in  which,  after  thorough  division  of 
the  fraenum,  wide  separation  of  the  central 
incisors  was  reduced  by  natural  means  before 
the  eruption  of  the  canines,  \\hich,  however, 
were  partially  impacted. 

G.  Northcroft  (123),  in  a  recent  article,  de- 
scribes an  operation  m  which  he  dissects  away 
the  fraenum,  and  fixes,  by  means  of  bands  on 
the  central  incisors,  a  horseshoe-shajjed  w  ire 
convex  upwards  and  not  quite  touching  the 
gum,  to  keep  the  lip  away  and  prevent  reunion. 
6.  Position  of  Crypt  and  Total  Displacement. 
Teeth  occasionally  erupt  in  positions  quite 
remote  from  their  normal  situation  and  in  an 
abnormal  direction.  This  happens  most  fre- 
quently in  the  case  of  the  upper  canine,  which 
may  appear  in  a  nearly  horizontal  direction 
high  up  on  the  buccal  side  of  the  arch,  or  in  the 
palate.  A  central  incisor  may  be  similarly 
misplaced,  and  when  it  appears  in  the  palate 
may  be  rotated  through  a  quarter  of  a  circle 
about  its  ape.v.  The  probable  cause  is  some 
congenital  aberration  of  the  crypt,  or  of  the 
direction  of  the  axis  of  the  crown  in  the  crypt. 
An  extreme  degree  of  this  condition  may  prevent 
the  tooth  erupting  at  all,  even  in  cases  where 
there  is  no  marked  encroachment  by  the  other 
teeth  on  the  space  that  it  should  occupy,  at  any 
rate  until  a  period  considerably  later  than  that 
of  its  normal  eruption.  This  occurs  most  often 
in  the  case  of  one  or  both  upper  canines  (see 
Figs.  136,  137,  138,  139). ^ 

It  may  be  objected  that  the  cause  of  this  form 
of  abnormality  is  not  strictly  a  local  one,  but 
rather  developmental.  However,  the  effects  are 
local ;  and  the  origin,  although  ob.scure,  is  not 
connected  with  gross  defects  of  growth  of  bone, 
such  as  wiU  be  considered  in  Classes  II  and  III. 


1  Excellent  examples,  including  premolars  and 
molars,  of  abnormalities  of  this  class,  in  dried  speci- 
mens, are  illustrated  by  J.  F.  Colyer  (Dental  Record, 
Feb.  1914,  p.  87). 


88 


Treatment. — The  question  of  treatment  for  all 
these  gross  abnormalities  is  difficult.  A  radio- 
graph should  always  be  taken,  in  order  to 
ascertain  the  character  and  direction  of  the  root. 
If  this  is  not  curved  or  bent  or  dilacerated,  a 
partially    erupted    tooth    may    by    mechanical 


Fig.  134. — Absence  of  riglit  lateral  incisor,  small  size  and  abnormal 
form  of  left  lateral,  separation  of  centrals  due  to  suj^erfluous 
space.     (S.  Merkill  Weeks  :  Dental  Cosmos.) 


means  be  moved  to  its  normal  position,  after 
space  has  been  made  for  it  when  this  has  been 
encroached  upon.  In  other  cases,  where  the 
tooth  is  grossly  misplaced  or  malformed,  extrac- 
tion is  the  only  treatment  possible.  In  the  case  of 
an  unerupted  tooth,  the  possibilities  of  bringing 
it  into  position  depend  chiefly  upon  the  direction 
of  the  axis  of  the  tooth.  If  space  is  obtained 
by  movement  of  the  adjacent  teeth,  or  in  the 
case  of  a  canine  by  the  extraction  of  a  first 
premolar,  which  is  sometimes  justifiable,  the 
tooth  may  be  induced  to  erujit  by  the  temporary 
use  of  a  denture,  but  it  is  wise  not  to  extract 
another  tooth  unless  there  is  every  probability  of 
ultimate  eruption  of  the  aberrant  tooth .  Success 
has  followed  the  operation  of  cutting  clown  uijon 
a  misplaced  canine,  fixing  into  it  an  iridio-plati- 
num  pin,  and  applying  a  rubber  ligature. 

7.  The  habit  of  thumb,  fmger,  toe,  lip,  or  tongue 
sucking  is  very  common  in  infancy  or  early 
childhood,  but  is  usually  abandoned  before  any 
harm  results  to  the  teeth  or  jaws.  The  thumb 
and  finger  are  by  far  the  most  frecpient  agents, 
and  the  kind  of  deformity  produced  depends 
uf)on  the  manner  in  which  one  or  other  of  these 
is  used.  In  the  case  of  the  thumb,  the  crowns 
of  the  upper  central  incisors  are  pushed  forwards, 
and  to  a  less  degree  those  of  the  lower  incisors 
backwards  (see  Fig.  140).  If  tlie  extended  fingers 
are  used  in  a  similar  manner  w  ith  the  extremities 
pushed  up  against  the  palate,  a  greater  amount 


of  space  is  taken  up  and  marked  proclination  of 
all  the  upper  incisors  will  result ;  the  condition 
may  be  exaggerated  by  the  intrusion  of  the  lower 
lip.  This  deformity  may  be  seen  sometimes  with 
the  deciduous  teeth  (see  Fig.  226),  but  the  cases 
that  usually  come  under  notice  are  those  of 
deformity  of  the  permanent  teeth  when 
the  habit  has  been  long  continued.  It 
is  possible  that  the  deformity  may  occur 
as  the  result  of  earlier  finger-sucking, 
even  though  the  habit  has  been  aban- 
doned before  the  eruption  of  the 
permanent  teeth,  o\\'ing  to  displace- 
ment of  the  deciduous  teeth  and  the 
alveolus  and  the  crypts  of  the  per- 
manent teeth.  A  similar  deformity  is 
produced  by  lip-sucking. 

It  is  important  to  distinguish  this 
condition  from  other  cases  of  real  and 
apparent  protrusion  due  to  other  more 
remote  and  deep-seated  causes  to  be 
described  later.  There  is  not  usually 
any  abnormality  of  position  or  occlusion 
of  the  other  teeth,  but  Guilford  (82)  and 
Colyer  have  pointed  out  that  by  means 
of  the  separation  of  the  jaws  and  the 
muscular  action  of  the  cheeks  in  pro- 
ducing suction,  a  lingual  inclination  of 
the  premolars  and  molars  is  sometimes 
l^roduced.  The  condition  is  a  purely 
local  one  due  to  a  local  cause,  and  is  not  associ- 
ated with  any  errors  in  bony  development  of 
the  body  or  ramus  of  the  mandible,  or  contrac- 
tion of  the  maxilla. 


Fig.    135. — Separation    of    upper    central    incisors    by 
abnormal  traenum  labii.     (H.\rolu  C'H.iPMAN.) 

If  the  fingers  are  inserted  horizontally  or 
hooked  over  the  lower  teeth,  a  quite  different 
deformity  will  result.  The  upper  incisors,  and 
possiUy  canines,  will  be  forced  upwards  and 
slightly  forwards,  and  the  lowers  downwards  and 
forwards,   so   that    a    species   of    open    bite   is 


89 


produced.     Here  again  the  condition  must  be  Treatment. — The  treatment  of  these  conditions 

carefully  distinguished  from  the  cases  of  open  is  easy;    the  habit  must  be  cured  by  moral  or 

bite  associated  with  errors  of  occlusion  and  bony  '   mechanical   means,   and  the  teeth   reduced   to 
development. 


Fig.  l',m. — Left  upjjer  central  incisor  erupting  tlirough  lip  in  patient  aged  ',i6.  For  some  years  previously  a 
hard  swelling  had  been  noticeable  in  the  region  where  this  tooth  subsequently  presented.  About  three 
years  ago  the  patient  received  a  blow  on  the  face,  which  was  followed  by  considerable  inflammation  and 
swelling,  and  the  tooth  shortly  afterwards  appeared  through  the  lip  and  gradually  came  lower  to  its 
present  position  (January  1912).  On  examination  inside  the  mouth  there  seemed  no  indication  that  the 
tooth  had  ever  erupted  high  up  in  the  sulcus.     (G.  G.  Campion.) 


In  both  these  deformities  the  condition  is 
plainly  due  to  an  evenly  distributed  pressure, 
and  can  generally  be  easily  diagnosed  from  cases 


Fig.  137. — Transposition  of  left  canine  and  first  premolar 
(G.  NORTHCKOFT.) 

of  misplacement  caused  by  other  local  influences. 
An  interesting  case  of  buccal  occlusion  of  the 
right  lo«er  premolars  and  molars  caused  by 
tongue-sucking  is  recorded  by  J.  H.   Badcock 

{11M14).  1 


their  normal  position.  Retention  will  only  be 
necessary  for  a  short  period,  when  the  cause  has 
been  removed. 

8.  Premature  Loss  of  Deciduous  or  Permanent 
Teeth. — The  premature  loss  of  deciduous  teeth 
is  a  frecjuent  cau.se  of  misplacement  of  the 
permanent  teeth.  It  may  happen  that  in  a 
particular  case  other  causes  leading  to  diminu- 
tion of  the  size  of  the  arch  or  alteration  in 
its  shape  may  contribute  to  tlie  same  result ; 
but  in  the  study  of  abnormal  positions  of  the 
teeth,  consideration  of  the  effects  of  definite 
causes  is  more  instructive  than  the  description 
of  a  series  of  cases  more  or  less  alike  but 
associated  with  entirely  different  aetiological 
factors,  \\^len  the  effects  of  definite  causes 
are  clearly  understood,  it  liecomes  not  very 
diiWcult  to  picture  the  beginnings  of  more 
complex  forms. 

For  the  jiurpose  of  this  group,  tlien,  it  will 

be  assumed  that  bony  development  is  normal 

or  nearly  so,  and  that  the  character  of  the 

dental  arch  is  normal,  except  in  so  far  as  loss  of 

teeth  may  have  caused  contraction. 

Deciduous  Incisors. — The  premature  loss  of 
deciduous  incLsors  does  not  generally  conduce 
to  any  very  great  deformity.     It  is  probable 


90 


that  tlie  consequent  loss  of  function  may  to 
some  extent  inliibit  the  growth  of  bone  in  the 
pre-maxilla  and  anterior  portion  of  tlie  mandible, 
but  definite  information  on  this  point  is  wanting. 


Fig.  ]:JS. — Prominence  on  right  side  in.li.at.s  an 
uncTupted  permanent  tooth  grossly  misplared. 
(G.  NOHTHCROFT.) 

It  has  l)een  pointed  out  by  G.  Northcroft  (119) 
(120),  however,  that  premature  eruption  of  the 
permanent  incisors  before  the  first  permanent 
molars  are  fully  erupted  and  in  occlusion  is  a 
source   of  serious   abnormality,   and   this 
premature  eruption   is   probably  encour- 
aged, if  not  directly  brought  about,   by 
premature  loss  of  tlie  deciduous  incisors". 
Deciduous  Canines.— It  does  not  often 
happen  that  the  deciduous  canines  are  lost 
prematurely   unless    they   are   extracted; 
but,  in  the  case  of  the  mandible  especially, 
these    teeth   are   sometimes    removed    to 
make  room   for  the  lateral  incisors.     It 
ynl\  often  be  found  that  when  the  growth 
of   the  jaw  has  not   kept  pace  with   the 
eruption  of  the  anterior  teeth— a  question 
that  will  he  considered  more  fully  later — 
the  lower  lateral  incisors  erupt  "lingually 
and  slightly  overlap  the  permanent  centrals 
and  deciduous  canines,  because  the  space 
formerly  occupied  by  the  deciduous  laterals 
is  not  sufficient  for  their  accommodation 
(see  Figs.  141,  142).     The  extraction  of  the 
deciduous  canines  is  not  usually  correct 
or  justifiable,  except  where  the  subsequent 
removal  of  the  erupted  or  unerupted  first 
premolars    is    contemplated — a    question 
that    will   also    be   discussed   later.     The 
proper  treatment  is  to  advance  the  centrals, 
which  are  really  posterior  to  their  normal 
position,    and   move    the   canines   in    an 
antero-buccal   direction,   and   then  reduce   the 
laterals  to  their  correct  places ;  in  this  way  the 
growth  of  bone  will  be  stimulated,  and  the  upper 
incisors   will    not    be   allowed   to   fall  back  to 
the  position  of  the  lower.     A  similar  condition 
does  not  so  often  arise  in  the  ujjper  jaw;  the 


laterals  usually  find  their  way  into  position, 
perhaps  somewhat  rotated. 

The  effect  of  extraction  of  the  deciduous 
canines  is  twofold.  The  lateral  incisors  encroach 
on  the  space  that  ought  to  be  occupied  later  by 
the  permanent  canines,  and  the  deciduous  molars 
(or  the  premolars  at  a  later  stage)  move  forward 
under  the  influence  of  the  pressure  of  the  re- 
cently erupted  first  permanent  molars  and  the 
developing  bone  in  their  vicinity  and  the  soft 
parts  behind  them.  The  latter  result  is  par- 
ticularly likely  to  happen  ui  the  mandible. 
When  it  is  remembered  that  the  deciduous 
canine  is  considerably  smaller  than  the  per- 
manent canine,  and  that  in  the  normal  course 
space  for  the  latter  is  only  obtained  by  the 
buccal  translation  and  spacing  of  the  anterior 
deciduous  teeth  and  the  buccal  movement  of 
the  deciduous  molars,  it  will  become  obvious 
that  the  almost  certain  result  of  further  dimi- 
nution of  sjjace  will  be  buccal  eruption  of  the 
permanent  canines. 

Treatment. — The  correct  treatment  of  the 
ultimate  condition  depends  upon  whether  the 
reduction  of  space  has  been  caused  mainly  by 
the  anterior  or  the  posterior  teeth,  or,  in  other 
words,  whether  the  incisors  are  placed  too  far 


Fig.  139. — Kailm^raph  of  case  shown  in  Fig.  138. 

lingually  or  not.  In  the  former  case,  the  correct 
course  to  pursue  is  to  expand  the  anterior  por- 
tion of  one  or  both  arches,  as  may  be  required. 
In  the  latter  case,  and  Avith  normal  occlusion  of 
the  posterior  teeth,  a  premolar  on  each  side  of 
both  jaws  should  be  removed.     As    a   general 


91 


rule,    the    first    premolars    should    be    chosen  j  The   ideal   treatment,   recommended   by   some 


because  mechanical  treatment  is  tlien  usually 
unnecessary;  but  if  the  amount  of  space 
required  is  small,  say  less  than  half  the  width 


operators,  would  be  to  move  back  all  the 
posterior  teetli.  t)ut  when  all  the  evils  attendant 
upon  extensive  tooth-movements  are  considered, 
the  advantages  do  not  seem 
sufficient  to  justify  the  treatment. 
Ho\\  ever,  if  adopted  early,  before 
the  eruption  of  the  premolars, 
backward  movement  of  the  first 
permanent  molars  may  be  under- 
taken. The  question  of  extraction 
of  upper  laterals,  or  of  a  lower 
central,  does  not  usually  arise  in 
the  case  of  deformity  due  to  pre- 
mature loss  of  deciduous  canines  ; 
it  wiU  be  discussed  m  connection 
with  defective  development  of 
the  anterior  portion  of  the  mouth. 

First  Deciduous  Molars. — The  premature  loss 
of  these  teeth,  unless  very  early,  does  not  usually 


Fig.  140. — Proclination  of  upper  incisors  and  retro- 
clination  of  lower  incisors  due  to  thumb-sucking. 
(.J.  E.  Spiller.) 


Fig.  142. — Lateral  deviation  of  lower  incisors  duo  to 
premature  loss  of  right  deciduous  canine.  (G. 
NORTHCROFT.) 


of  a  premolar,  or  if  tlie  second  premolars  are  lead  to  much  deformity.  If  a  single  molar  is 
carious,  then  those  teetli  should  be  preferred  ,  lost  the  occlusion  of  the  remaining  teeth  is 
for  extraction,  liecause  tlie  first  premolars  can  i  generally  sufficient  to  prevent  forward  move- 
ment of  the  posterior  teetli,  and 
even  ^\here  upper  and  lower  on  one 
side  are  lost,  the  for\\ard  movement 
is  often  but  slight ;  the  first  premolars 
generally  erupt  prematurely  in  such 
cases  and  fill  tlie  sjiace,  even  as  early 
as  the  eighth  year.  Turner  (155, 
]).  193)  states  that  if  a  first  upper 
deciduous  molar  is  lost  at  about  seven 
years,  the  arcli  tends  to  become  flat 
and  to  carry  the  lower  with  it,  and 
tliat  tliere  will  thus  be  insufficient 
space  for  the  permanent  teeth,  so 
Fig.  141.— Rotation  and  postplacement  of  upper  lateral  incisors  and  that  the  canme  or  a  premolar  cannot 
buccal  displacement  of  canines,  due  to  deficient  anterior  develop-  reach  proper  alignment,  and  even  the 
ment  and  probably  premature  loss  of  deciduous  canines.   (Norm.\n     incisoi'S   may  be  pushed   in  a  lingual 

^""""~"  '  direction.     But,  as  he  also  remarks, 


G.  Bennett.) 


easily  be  moved  backwards  to  allow  the  canines 
to  erupt  into  normal  alicnment,  and  the  re- 
mainder of  the  space  gained  will  be  closed 
naturally  by  forward  movement  of  the  molars. 


a  well-formed  lower  deciduous  arch  and  the 
inter-digitation  of  cusps  may  be  enough  to 
prevent  this,  and  it  is  probable  that  in  most 
instances  such  is  the  case. 


92 


Second  Deciduous  Molars. — The  premature 
loss  of  tlie  second  deciduous  molars  is  a  frequent 
cause  of  misplacement  of  the  permanent  teeth ; 
the  loss  of  upper  and  lower  on  one  side  before 
the  second  premolars  are  ready  to  erupt  removes 


Fig.  143. — Forward  jiim\  im.iil  "f  lirsl  upper  per- 
manent molar  duo  to  preniatiiro  loss  of  second 
deciduous  molar ;  early  treatment.  Lower  figure 
shows  results  of  treatment.  (G.  Northcrofx  : 
Trans.  B.S.S.O.  ;  Dental  Record.) 

every  obstacle  to  a  for\\'ard  movement  of  the 
first  permanent  molars.  It  should  not  be 
imagined  that  there  is  in  these  teeth  any  in- 
herent power  of  translation  ;  they  simply  move 
in  the  direction  in  which  they  are  pushed,  or 
in  which  resistance  is  least  or  absent.  About 
this  period  the  growth  of  bone  around  the 
erupting  or  recently  erupted  first  permanent 
molars  and  about  the  angle  of  the  mandible  and 
posterior  border  of  the  maxilla  is  very  consider- 
able. It  is  probable  that  the  developing  second 
permanent  molars  still  enclosed  in  their  crypts 
afford  a  stimulus  to  this  backward  growth  of 
both  jaws.  The  jjurpose  of  this  growth  is 
clearly  to  afford  room  for  these  first  and  second 
molars,  and  it  would  seem  that  a  deposit  of 
bone  around  teeth  ^^ould  not  produce  any  force 
likely  to  propel  them  in  any  direction.  How- 
ever, the  eruption  of  these  molars  at  different 
periods  takes  place  in  a  confined  space  ;  in  the 
mandible  this  is  most  marked,  and  the  tooth  is 
pushed  through  between  the  ascending  ramus 
behind  and  the  tooth  in  front ;  in  the  maxilla 
the  tooth  develops  high  up  near  the  pterygo- 
maxillary  fissure  and  travels  down\\'ards  and 
rotates  forwards  in  consequence  of  the  growth 
and  expansion  of  the  maxillary  sinus  (95).  (See 
p.  30.)  Whatever  may  be  the  actual  force  that 
causes  teeth  to  erupt,  it  is  obvious  that  it  must 


be  considerable  to  overcome  the  resistance 
encountered,  and  in  the  case  of  the  first  lower 
permanent  molar,  if  the  second  deciduous  molar 
has  been  lost,  the  confined  space  is  relieved 
in  that  direction,  and  the  elastic  resistance 
of  the  soft  tissues  behmd  will  suffice  to  push 
the  erupting  tooth  forward.  The  slight  back- 
ward curve  of  most  lo^er  molar  roots  (especially 
the  third  molars)  is  evidence  of  a  forward 
movement  durmg  normal  eruption.  J.  F.  Colyer 
(53)  considers  that  forward  movement  of 
the  first  permanent  molars  "  occurs  mainly 
in  mouths  where  the  growth  of  jaws  is  inter- 
fered with  by  want  of  function,  either  due 
to  insufficient  mastication  or  lack  of  nasal 
breathing."  He  is  inclined  to  think  that  if, 
by  removal  of  the  deciduous  molars,  tlie  perma- 
nent molars  are  rendered  functional.  "  the 
growth  of  the  jaw  wUl  be  stimulated  and  room 
made  for  the  development  of  the  second  and 
third  molars,  with  no  forward  pressure  from 
those  teeth,  and,  with  the  first  molars  occluding 
correctly,  there  will  be  little,  if  any,  forward 
movement."  For  the  rea.sons  given,  however, 
and  from  clinical  experience,  the  writer  does  not 
think  this  view  can  be  maintained. 

In  the  case  of  the  upper  molar  the  reasons 
for  forward  movement  are  not  cjuite  so  clear, 
but  in  the  normal  process  there  is,  as  has 
been    explained,     a     downward    and    forward 


^■ispace 

■  7?t  J^i^^^^^^^^B 

H- 

^^^^^^^^^1 

^B^^tTTT 

"  .  i\  nonn.ll            ^    ^^H 

^V>M 

^^B 

Fici.  144. — Similar  to  143.     (G.  Northcroft  :    Trans. 
B.S.S.O.  ;  Dental  Record.) 

movement,  which  brings  the  tooth  into  close 
apposition  with  the  tooth  anterior  to  it,  and 
if  the  latter  is  absent  it  is  not  remarkable 
that  the  forward  movement  should  be  ex- 
cessive. Exact  measurements  have  not  yet 
been  made   to  show  how  far  the   upper   first 


93 


permanent  molar  moves  forward  in  the  normal 
process  of  eruption  and  afterwards.  It  has 
been  pomted  out  that  its  relationship  to 
the  malar  process  does  not  afford  sufficient 
evidence,  because  this  portion  of  bone  is  itself 
added  to  posteriorly  and  absorbed  anteriorly 
during  the  process  of  growth.  Edward  H. 
Angle  (4)  has  shown  that  variability  in  position 
of  the  first  upper  molar  is  much  less  extensive 
than  in  the  case  of  the  lower.  He  correlates 
.such  variability  as  does  occur  with  variation 
of  type  in  different  races  and  different  hidi- 
viduals,  and  even  goes  so  far  as  to  say  that  when 
an  upper  molar  moves  forward  in  consequence 
of  loss  of  the  second  deciduous  molar,  such 
movement  is  even  hardly  greater  than  would 
have  occurred  naturally  a  few  years  later. 
Angle  is  probably  correct  in  regarding  the  first 
upper  permanent  molar  as  a  tooth  that  varies 
but  little  in  position,  but  clinical  experience 
hardly  supports  his  extreme  contention.  L.  S. 
Lourie  (108)  shows  convincing  examples  of 
considerable  forward  movement  of  first  upper 
molars  following  loss  of  deciduous  teeth.  See 
also  E.  A.  Bogue  (32)  (34). 

The  natural  occlusion  of  the  first  permanent 
molars,  ichen  they  are  fully  erupted,  usually 
prevents  a  forward  movement  of  one  tooth  only. 


molar  occludes  with  it  and  is  thereby  locked. 
The  loss  of  the  lower  deciduous  tooth  is  there- 
fore relatively  less  important,  and  it  may  be 
said  that  the  second  upper  deciduous  molar  is 
the  most  important  tooth  of  its  set  in  relation 


Fig.  145. — Flattening  of  arch,  backward  movement  of  left 
lower  canine  and  first  premolar,  and  lingual  displacement 
of  second  prenaolar,  due  to  premature  loss  of  second 
deciduous  molar.  (The  permanent  molar  appears  to  have 
moved  forwards,  but  this  is  not  so ;  the  occlusion  was 
normal.)     (J.  G.  Turner:  Brit.  Dent.  Jour.) 

If  the  second  U2:)per  deciduous  molar  alone  has 
been  lost  there  may  be  some  forward  movement 
of  the  first  upper  molar,  but  it  is  jjrobable  that 
the  retention  of  the  second  upper  deciduous 
molar  only  is  sufficient  as  a  mle  to  prevent 
forw-ard  movement  of  either  permanent  tooth, 
for  the  reason  that  the  first  lower  permanent 


Fig.  146. — Flattening  of  arch  and  impaction  of  second 
right  premolar  (indicated  by  small  triangle)  due 
to  premature  loss  of  second  deciduous  molar. 
(B.  Frank  Gr.\y  :  Dental  Cosmos.) 

to  the  permanent  dentition.  Its  premature 
loss  is  more  conducive  of  evil  than  that  of  any 
other  deciduous  tooth  (see  Figs.  143,  144). 

The  effects  of  this  forward  movement  of  the 
first  permanent  molars  in  both  upper  and  lower 
jaws,  where  the  arches  are  of  normal  size  and 
shape,  Ls  obviously  to  reduce  the  space 
available  for  the  premolars  and  canhies ; 
there  may  also  be,  as  J.  G.  Turner  (155, 
p.  241)  has  shown  by  excellent  illustrations 
(see  Fig.  145),  a  flattening  of  the  arch  due 
to  backward  and  lingual  movement  of  the 
first  deciduous  molars  and  teeth  anterior 
to  them  (see  Fig.  146).  The  actual  de- 
formity produced  depends  upon  two 
factors  namely,  the  amount  of  movement 
and  the  order  of  eruption,  and  possibly 
also  on  the  density  of  the  bone  around 
the  roots  of  the  anterior  teeth. 

If    the    forward    movement    has    been 
considerable,  the  last  tooth  to  erupt  will 
be  prevented  from  coming  into  alignment. 
This  may  be  either  the  second  premolar  or 
the   canine ;    in  the   former  case    lingual 
deviation  is  the  most  frequent,  and  in  the 
latter  buccal  eruption  (see  Figs.  110,  147, 
148,  149).     In  an  early  stage  of  eruption  of 
the  upper  canhies,  pressure  on  the  roots 
of  the  lateral  incisors  may  cause  rotation, 
and  proclination  of  the  crowns ;  the  un- 
erupted  lower  canine  may  conduce   to   a 
fan-shaped  disposition  of  the  lo«er  uicisors 
by  pressure  on  the  roots.     It  should  be  remem- 
bered, however,  that  the  second  deciduous  molar 
is    larger    than    the    second    premolar.      It   is 
possible   that   this   little   extra   space    may   be 
made  use  of  for  the  benefit  of  the  permanent 
canine,  which  is   considerably  larger  than    its 
predecessor ;    it    is    more    probable,    however, 


94 


that  the  space  required  by  the  eanme  is 
normally  found  by  its  translation  into  a  larger 
arcli    tlian    that    occupied    primarily    by    the 


Fig.  14"- — Buccal  displacement  of  right  canine  due  to 
premature  loss  of  deciduous  molars  and  forward 
movement  of  first  permanent  molar.  (.J.  E. 
Spiller.) 

deciduous  teeth,  and  that  the  little  extra  space 
provided  by  the  large  second  deciduous  molar 
affords  some  latitude  for  \\  hat  should  properly 
be  the  last  of  these  teeth  to 
erupt,  namely,  the  second  pre- 
molar, and  that  it  is  closed  by  a 
slight  forward  movement  of  the 
molar.  The  character  of  the 
abnormality  produced,  of  course, 
varies  greatly  with  other  con- 
tributory causes,  beyond  the 
actual  amount  of  space  avail- 
able, and  may  be  to  some  extent 
corrected  or  increased  by  the 
occlusal  relations  with  the  oppos- 
ing teeth  that  become  established. 
Where  the  forward  movement 
of  the  molars  has  been  slight, 
the  subsequently  erupting  teeth 
are  not  prevented  from  coming 
into  alignment,  but  only  impeded 
in  their  progress  ;  that  is  to  say, 
the  force  producing  eruption  has 
more  to  contend  with  than  usual, 
but  may  be  sufficient  to  push 
aside  the  obstructing  teeth. 
When  the  second  premolar  erupts 
after  the  canine,  the  result  may 
be  only  a  slight  abnormality  of 
occlusal  relationship,  or  a  slight 
pressure  brought  to  bear  on  the 
front  teeth.  It  is,  however,  where 
the  canine  erupts  last  that  any 
effects  on  the  front  teeth  may 
more  often  be  noticed.  Such  results  may  be, 
in  the  maxUla,  a  slight  rotation  of  the  lateral 
incLsors  and  lapping  of  them  over  the  centrals, 
a  slight  rotation  of  the  centrals,  or  a  slight 
proclination  of  the  incisors  generally,  and  they 


are  more  likely  to  occur  when  there  is  some 
slight  tendency  to  these  forms  of  deformity. 
It  is  very  doubtful  whether  any  marked  degree 
of  proclination  or  other  deformity  is  ever  pro- 
duced by  the  erupting  canines  when  the  incisor 
teeth  are  firmly  implanted  in  a  normal  manner ; 
it  is  probable  that  the  typical  V-shaped  arch  is 
never  produced  in  this  way.  In  the  case  of  the 
mandible  the  only  result  likely  to  happen  is  an 
exaggeration  of  any  slight  degree  of  imbrication 
or  "  fanning  "  of  the  incisors  already  present. 

Treatment. — Treatment,  in  the  case  of  slight 
forward  movement  and  slight  deformity,  should 
consist  in  backward  movement  of  the  molars 
and  correction  of  any  misplaced  teeth.  It  is 
not,  however,  wise  to  adopt  this  method  where 
the  movement  has  been  at  all  considerable,  or 
after  the  eruption  of  the  second  permanent 
molars.  Extraction  is  then  the  best  remedy, 
for  expansion  is  inadmissible  in  an  arch  of 
normal  character  and  size,  and  extensive  back- 
ward movement  does  not  offer  advantages 
commensurate  with  the  extent  and  difficulties 
of  the  proce.ss.  Cryer  (60)  considers  that 
successful  backward  movement  of  a  first  lower 


Fig 


[ormal  occlusion  of  upper  molars  and  preinolars  and  buc- 
cal displacement  of  canines,  due  to  forward  movement  of  molars. 
(J.  E.  Spiller.) 


ntolar  half  its  width  after  eruption  of  the  second 
molars  is  impossible.  The  selection  of  the 
particular  tooth,  or  teeth,  to  be  extracted 
depends  upon  varying  circumstances,  such  as 
the  character  of  the  deformity,  and  condition 


95 


as  to  caries ;  and  it  is  impossible  to  lay  down 
definite  rules.  It  may  be  said  that  the  molars 
should  be  preserved  unless  carious  to  an  extent 
that  renders  permanent  filling  impossible ; 
that  for  deformities  produced  by  the  process 
inider  discussion  extraction  of  the  laterals  is 
scarcely  ever  justifiable ;  and  that  an  aberrant 
premolar  and  the  corresponding  tooth  in  the 
opposite  jaw,  or  a  pair  of  premolars  (right 
and  left)  to  make  room  for  canmes,  are  the 
teeth  usually  to  be  chosen.  It  is  generally 
best  to  extract  symmetrically  on  both  sides  of 
the  mouth ;  otherw  ise  a  deviation  of  the 
central  incisors  to  one  side  of  tiie  median 
line  w  ill  almost  certainly  follow.  Some  amount 
of  such  deviation  is  usually  associated  with 
buccal  eruption  of  one  upper  canme,  and  will 
be  increased  by  extraction  on  one  side  only. 


Fig.  149. — Lingual  disijhiceinent  of  second  left  upper 
premolar,  due  to  forward  movement  of  first  molar. 
(J.  E.  Spiller.) 

In  the  mandible,  the  extraction  of  a  single 
incisor  (central  for  choice)  may  be  good  treat- 
ment, when  there  is  some  degree  of  imbrication 
or  "  fanning  ",  to  make  room  for  a  canine.  The 
most  misplaced  tooth  should  not  necessarily  be 
selected,  but  preference  should  be  given  to  a 
tooth  labially  misplaced  rather  than  lingually, 
as  the  latter  is  more  likely  to  be  reduced  by 
natural  forces. 

Mechanical  treatment  is  not  often  required, 
but  any  tooth  locked  by  false  occlusion  will 
always  need  correction,  and  some  application 
of  artificial  force  may  be  necessary  in  other 
cases. 

Premature  Loss  of  Most  or  All  of  the  Deciduous 
Teeth. — The  elTects  of  extraction  of  most  or  all 
of  the  deciduous  teeth  (including  second  molars) 
before  the  age  of  six  is  not  definitely  known.  It 
is  almost  certain  that  there  is  a  forward  transla- 
tion of  the  first  permanent  molars  in  course  of 
eruption,  but  ^^•hether  there  is  any  tendency  to 
prevent  these  teeth  eruj)ting  to  their  full  extent, 
and  thereby  cause  an  undue  approximation  of 
the  jaws  and  secondary  proclination  of  the 
upper  mcisors,   is  not   known.     It  is  at  least 


probable  that  the  growth  of  bone  of  the  jaws 
depends  upon  the  presence  and  function  of  the 
deciduous  teeth,  as  well  as  upon  the  stimulus 
of  the  development  of  their  successors,  and  it 
is  unlikely  that  such  a  gross  interference  with 
natural  routine  can  be  unproductive  of  harmful 
results.  It  should,  however,  be  clearly  under- 
stood that  such  treatment  may  be  imperatively 
demanded  on  grounds  of  hygiene  exceeding  in 
importance  the  risk  of  deformities  to  follow; 
although  it  may  be  borne  in  mind  that  where 
some  teeth  can  be  preserved  the  second  molars 
and  the  canines  are  the  most  valuable. 

The  method  has  been  largely  practised  by 
J.  F.  Colyer  at  the  Royal  Dental  Hospital  of 
London  in  the  case  of  children  \xith  septic 
mouths.  He  has  kept  careful  records  and  seen 
many  of  the  patients  years  after,  and  does 
not  believe  that  deficiency  of  bony  growth 
necessarily  follows  (53)   (54). 

First  Permanent  3Iolars.— The  ill  effects  of 
loss  of  one  or  more  first  permanent  molars 
depend  upon  the  age  at  which  they  are  removed. 
They  are  m  themselves  by  far  the  most  useful 
masticating  teeth  in  the  mouth,  and  should 
receive  careful  and  frequent  attention  from  the 
time  of  their  eruption.  But  the  j^resent  discus- 
sion is  concerned  chiefly  ^\ith  the  effects  of  their 
loss  on  the  shape  of  the  arch  and  the  position 
of  the  other  teeth ;  the  artificially  created 
space  influences  development  anteriorly  and 
posteriorly  in  different  ways. 

Early  Loss. — It  will  be  well  first  to  consider 
the  evils  arising  from  extraction  prior  to  the 
full  eruption  of  the  premolars.  The  loss  of 
both  upper  teeth,  or  both  lowers,  or  all  four, 
\\ill  throw  the  force  of  mastication  entirely 
on  the  deciduous  molars  if  these  are  still 
in  ijlace,  or  in  their  absence  on  the  anterior 
teeth.  In  the  former  case,  if  the  transition 
from  the  deciduous  to  the  permanent  dentition 
proceeds  normally,  the  first  premolars  will 
erupt  and  occlude  before  the  second  deciduous 
molars  are  shed,  but  there  is  great  probability 
that  during  this  process  the  forces  of  masti- 
cation will  be  thrown  at  one  time  or  another 
on  the  incisor  teeth.  It  is  in  fact  one  of 
the  chief  functions  of  the  first  permanent 
molars  to  take  up  the  forces  of  mastication 
during  a  variable  period  between  the  eighth 
and  the  twelfth  years,  while  the  premolarsand 
canines  are  taking  their  places  in  the  arch ; 
that  is  to  say,  in  the  orderly  but  delicate  process 
of  transition,  their  duty  is,  as  it  were,  to  hold 
the  fort  while  the  reserves  are  being  mobilized. 

The  effect  of  mastication  on  the  incisor  teeth 
is  a  proclination  of  the  uppers  and  to  a  less 
extent  a  retroclination  of  the  lowers,  associated 
with  undue  approximation  of  the  jaws.  This 
altered  relationship  of  the  jaws  is,  as  it  were, 
accejjted  by  the   subsequently  eruptmg  teeth, 


96 


which  do  not  erupt  to  their  normal  extent ;  and 
the  deformity  is  thus  perpetuated.  The  kind 
of  protrusion  produced  is  as  a  rule  not  only 
different  m  origin,  but  also  in  character,  from 
those  forms  to  be  described  later  whose  causa- 
tion is  more  recondite,  and  it  differs  in  important 
respects  from  that  caused  by  thumb  and  finger 


Flo.  150. — Pronouncod  overbite  of  incisors  due  to  loss 
of  first  permanent  molars.  (E.  E.  Hall  :  Items 
of  Interest.) 

sucking.  The  ends  of  the  roots  are  unaffected, 
but  the  teeth  are  inclined  forwards  and  some- 
what separated ;  in  other  words,  they  are  not 
translated  forwards  but  spread.  The  lower 
teeth  occlude  with  the  cmgula  high  up,  or  with 
the  gum  behind  the  cingula  (see  Figs.  211,  212). 
The  appearance  of  the  teeth  of  each  jaw 
considered  separately  may  be  similar  to 
that  produced  by  thumb  or  finger  sucking, 
but  in  the  undue  approximation  of  the  jaws 
the  condition  resembles  those  forms  to  be 
considered  later  that  are  associated  with,  if 
not  caused  by,  abnormal  bony  development. 
In  other  cases  excessive  overbite  occurs  with- 
out proclination  (see  Fig.  150).  \\^iere  all 
four  molars  have  been  lost,  there  will 
probably  be  later  on  some  movement  back- 
wards and  spacing  of  the  premolars ;  in 
some  cases  this  is  caused  by  the  interaction 
of  the  inclined  planes  of  the  coronal  surfaces, 
but  in  others  "  travelling  "  of  the  premolars 
occurs  while  they  are  still  unerupted  (see 
Figs.  151,  152).  The  greater  part  of  the 
space,  however,  will  be  taken  up  by  the 
second  permanent  molars,  which  do  not 
usually  become  tilted  when  the  first  per- 
manent molars  are  lost  so  early.  There 
will  also  probably  be  some  lateral  contraction  of 
the  arches,  as  J.  G.  Turner  (155,  p.  241)  has 
demonstrated  by  illustrative  models,  but  this 
does  not  necessarily  follow,  and  the  factor  that 
perhaps  determines  the  result  is  the  size  and 
development  of  the  tongue.  In  those  cases 
where  the  upper  teeth  only,  or  the  lower  only, 
are  lost,  the  opposing  second  molars  usually 
move    forward    nearly   completely    (one    unit) 


during  eruption,  so   as  almost  exactly  to  take 
up  the  positions  of  the  lost  teeth. 

Where  a  pair  of  teeth  on  one  side  of  the  mouth 
only  are  lost,  the  resultant  deformities  will  be 
limited  to  the  effects  on  the  premolars  of  that 
side,  together  with  a  slight  lateral  deviation  of 
the  incisors. 

Treatment. — The  treatment  of  the  type  of 
protrusion  described  above  consists  m  raising 
the  bite  sufficiently  to  allow  of  the  upper  in- 
cisors being  drawn  back  and  the  lowers  drawn 
forward  into  normal  occlusion,  and  in  retaining 
the  teeth  in  their  positions  until  the  complete 
eruption  and  normal  occlusion  of  the  premolars. 
There  is,  as  a  rule,  no  great  difficulty  in  this 
because  the  undue  approximation  of  the  jaws 
is  not  due  to  abnormal  jaw  formation.  If  the 
premolars  have  moved  back,  they  must  be 
brought  forward  and  retained  until  the  second 
permanent  molars  have  come  into  contact  with 
them,  and  into  normal  occlusion  witli  their 
opponents.  Where  there  is  contraction  of  the 
arch  or  arches,  in  spite  of  the  loss  of  teeth 
expansion  must  be  resorted  to,  normal  position 
and  occlusion  of  the  premolars  restored,  and 
the  teeth  retained  until  complete  eruption  and 
forward  movement  of  the  second  permanent 
molars  has  taken  place.  Excellent  results  ensue 
from  tliis  treatment. 

Deformities  limited  to  one  side  require  similar 
treatment  as  regards  the  premolars. 


Fig. 


151. — Backward  movement  of  premolars  on  both  sides, 
due  to  early  loss  of  first  permanent  molars.  Early  erup- 
tion of  third  molars.      (J.  F.  Govv.) 

Late  Loss. — Loss  of  all'  four  first  permanent 
molars  after  the  complete  eruption  of  the  jyremolars 
has  no  effect  on  the  incisor  teeth.  The  effect  on  the 
premolars  and  second  permanent  molars  depends 
very  definitely  on  the  age  at  which  the  extraction 
has  taken  place.  If  the  latter  teeth  are  already 
erupted  or  just  about  to  erupt,  there  will  be 
a  subsequent  forward  movement  and  forward 
tilting  of  the  lower  molars,  and  some  backward 


97 


movement  of  the  premolars.  If,  on  the  other 
hand,  the  loss  lias  occurred  before  about  the 
eleventh  year,  then  tlie  molars  will  come  forward 
with  little  or  no  tilting,  but  more  time  will  have 
been  given  for  the  backward  movement  of  the 
premolars  (see  Figs.   153,   154). 

J.  G.  Turner  (154)  states  that  in  the  maxilla 
the  second  molar  moves  forward  very  readily, 
but  that  in  the  mandible  movement  is  chiefly 
confined  to  the  premolars,  which  travel  back- 
wards (155,  p.  241).  No  doubt  this  is  true  of 
many  cases,  but  it  is  difficult  to  see  how,  with 
the  inter-digitation  of  cusps  in  a  normal  occlu- 
sion, the  lower  premolars  can  move  backwards 
unless  the  upper  do  likewise.  The  state  of 
eruption  of  the  premolars  at  the  time  of  extrac- 
tion of  the  molars  is  probably  a  determining 
factor. 

Treatment. — Treatment  consists  in  correction 
of  the  premolars,  and  drawing  forward  the 
second  permanent  molars  when  necessary. 

Loss  of  One  Molar  on  Either  Side. — When 
only  a  single  molar  on  either  side  has  been 
lost,  movement  of  the  premolars  is  prevented, 
except  to  a  very  slight  extent.  If  the  first 
lower  molar  has  been  lost  and  the  second  per- 
manent molar  is  already  erupted  or  nearly 
so,  the  second  lower  permanent  molar  will  be 
locked  by  occlusion,  and  become  tilted,  so  that 
nearly   all   the   space    remains    (.see    Fig.    122). 


tilting,   and   the   second   premolar   backwards. 
The  occlusion  is,  of  course,  very  imperfect. 

An  earlier  loss   of   one   first   molar   permits 
almost    complete    forward    movement    of    the 


Fig.  153. — Good  dccIush.h 
first  permanent  molars. 
Cosmos.) 


after   extraction    of    foiir 
(Matthew  Ckyer  :  Dental 


Fig.  152.- 


-Radiograph  of  case  shown  in  Fig.  151,  taken  before  the  second  right 
molar  was  removed. 


In  the  case  of  the  loss  of  the  first  upper  molar 
the  evil  is  not  quite  so  great,  as  the  locking 
is  less  complete,  and  the  second  upper  molar 
usually  moves  forward  to  some  extent  without 


second  molar  with  little  or  no  tilting  (see  Fig. 
155). 

Treatment. — Treatment  after  eruption  of  the 
second  molars  should  usually  consist  in  extrac- 
tion of  the  opposing  fir.st 
molar,  especially  when  this 
is  the  upper.  The  second 
molars  will  then  move  for- 
ward together  and  tilting  of 
the  lower  be  largely  pre- 
vented ;  if  this  has  already 
taken  place  it  can  be  remedied 
to  a  great  extent  by  force 
acting  in  a  forward  direction 
and  applied  as  near  the  roots 
as  possible.  After  the  tooth 
is  in  contact  with  the  second 
premolar  this  will  have  the 
effect  of  drawing  the  roots 
forward. 

Importance  of  First  Perma- 
nent Molars. — It  is  clear  that 
the  effects  of  loss  of  the  first 
permanent  molars  are  varied 
and  extensive,  and,  as  has 
been  stated,  their  treatment 
and  preservation  from  the 
time  of  eruption  is  of  cardinal 
importance.  It  may  be  said 
that  the  worst  results  follo«' 
very  early  loss  and  the  next 
worst  happen  with  late  loss,  the  least  evil  result- 
ing from  extraction  during  an  intermediate 
period  (about  the  tenth  and  eleventh  years). 
The  various  ill  effects  caused  by  unjustifiable 


98 


extraction  are  well  shown  by  E.  Forberg  (77) 
in  an  excellent  series  of  models,  and  the  question 


Fig.  154. — Good  occlusion  after  extraction  of  four 
first  permanent  molars  when  cusps  of  second 
molars  first  appeared.  (Matthew  C'ryer  :  Dental 
Cosmos.) 

is    well    discussed    and    illustrated    by    A.    C. 
Lockett  (107),  who  sums  up  the  ill  results  of 
injudicious     extraction     as 
follows — 

(1)  Complete    rum    of    a 

perfect  masticating 
surface. 

(2)  Movement      of      pre- 

molars  and  second 
molars. 

(3)  Tilting    of    second 

molars. 

(4)  Straightening    of    the 

curve  of  occlusion. 

(5)  Spacing. 

((5)  Elongation    of    unop- 
posed teeth. 

(7)  Overwork  of  anterior 
teeth. 

AU  of  these  ills  occur  at 
one  time  or  another  in  differ- 
ent cases,  but,  as  has  been 
shown  above,  the  particular 
effect  depends  very  mucli 
upon  concomitant  condi- 
tions, of  which  one  of  tlie 
most  important  is  the  date 
of  extraction  (or  period  of 
complete  destruction  by 
caries). 

Unfortunately  it  often 
happens  that  when  a  case 
comes  under  ol)servation  one 
(or  more)  of  these  teeth  is 
beyond  preservation.  It  is 
important  to  remember  that 
according  to  the  princi{)les  discus.sed  it  may  be 
necessary  sometimes  to  extract  all  four,  and  in 


other  cases  the  uppers  or  lowers  only.  It  is 
often  possible  to  preserve  them  temporarily  so  as  to 
extract  at  the  most  javourahle  moment.  When  a 
pair  of  molars  on  one  side  only  are  removed, 
movement  of  premolars  and  deviation  of  anterior 
teeth  must  be  prevented  until  complete  eruption 
of  the  second  permanent  molars,  as  already 
described. 

Other  Permanent  Teeth. — The  effect  of  the  loss 
of  other  permanent  teeth  is  usually  limited  to 
the  adjacent  teeth.  In  the  case  of  a  central 
incisor  it  is  sometimes  recommended  to  allow 
the  space  to  close,  or  to  close  it  by  mechanical 
means,  but  the  result  is  very  imperfect  and  ugly. 
On  the  whole  it  would  appear  to  be  better  to 
preserve  tlie  space  and  supply  the  tooth  by 
means  of  a  small  bridge  or  dummy  tooth 
attached  to  the  adjacent  central.  Loss  of  a 
lateral  is  less  obvious  and  may  in  some  cases 
be  left  untreated ;  but  where  there  is  any  dis- 
placement of  the  other  lateral,  and  it  appears 
that  the  spaces  can  be  closed  without  unduly 
diminishing  the  size  of  the  arch,  it  is  better  to 
extract   that   also.     Loss   of   a   canine   is   verv 


Fig.  155. — Normal  occlusion  on  right  side.  Good  forward  movement  of 
second  lower  molar  on  left  side,  some  backward  movement  of  premolars ; 
fair  occlusion  after  removal  of  first  molar  at  about  eight  years  of  age. 
(Norman  G.  Bennett.) 

rare.      Early   loss  of  a  premolar  allows  move- 
ment of  the  adjacent  teeth  and  entirely  prevents 


99 


normal    occlusion   being   established   (see    Fig. 
156).      Late    loss    affects   the  occlusion    of   the 


adopt  positions  which  are  consistent  with  their 
eruption  in  an  arch  smaller  than  that  for  which 
their  size  adapts  them  ;  that  is  to  say,  they  must 
exhibit  some  form  of  individual  rotation  or  over- 


FiG.  15(i. — Forward  movement  of  first  loft  upper 
molar  due  to  loss  of  second  premolar.  (H.\ROLn 
Ch.\pman.) 

adjacent  teeth  to  some  extent ;  it  is  sometimes 
well  to  extract  the  opposing  tooth,  and  prevent 
deviation  of  the  incisors  pending  for- 
ward movement  of  the  posterior  teeth. 
In  other  cases  a  dummy  tooth  may  be 
carried  on  an  adjacent  tooth  by  means 
of  a  C'armichael  or  staple  ci'own  ;  or  it 
may  be  left  untreated. 

Loss  of  a  second  permanent  molar 
before  the  eruption  of  the  third  molars 
is  usually  followed  by  complete  for- 
ward movement  of  the  third  molars 
into  the  space ;  loss  after  eruption  of 
the  third  molars  causes  tilting  in  a 
manner  similar  to  that  already  dis- 
cussed in  connection  with  the  first  and 
second  molars. 


Fig.  157. — Rotation  of  i-mlral  and  lateral  incisors 
due  to  deficient  anterior  development  (aged 
nine).     (N'orm.\n  G.  Bennett.) 

lapping.  Perhaps  the  most  usual  type  shows 
a  rotation  forwards  of  the  medial  surfaces  of 
the  central  incisors  (see  Figs.  157,  158,  193). 
In   that    case    the    laterals    may   find  room  to 


Fia.  158. — Rotation  of  upper  central  and  lateral  incisors  and  dis- 
placement of  left  lower  canine,  due  to  deficient  anterior 
development.     (Harold  Chapman.)  _^ 


CLASS  II.— Abnormal  Formation  of  a  Part  or  the 
Whole  of  either  Arch  due  to  Developmental 
Defects  of  Bone 

The  development  of  the  jaws  in  con- 
nection with  the  eruption  of  the  teeth, 
the  causes  of  imperfect  bony  develop- 
ment, and  the  parts  of  the  jaws  likely  to 
be  affected,  have  been  already  described. 
It  is  clear  that  the  effects  of  this  imper- 
fect development  upon  the  positions  of 
the  permanent  teeth  must  be  profound, 
and  it  will  be  convenient  to  consider 
them  under  two  aL'e-L'Voujjs. 

1.  Conditions  first  showing  themselves 
while  the  deciduous  molars  are  still  in  place. 

In  the  ]irc-Hiaxilla  the  |icrrnaiieHt 
mci.sors  usually  erupt  on  the  lal)ial  side 
of  the  arch  of  their  deciduous  predeces- 
sors ;   if.   therefore,  insufhcient  space  has  been 


erupt  in  normal  relation  with  the  centrals, 
though  really  placed  lingually  to  their  proper 
position.  This  condition  is  the  commence- 
ment of  the  typical  laterally  contracted  or 
V-shaped   arch,  as  will  be  seen  shortly.     The 


Fig 


159. — Rotation  of  upp.!-  lateral  iiu-isors  and  indirication 
of  lo%ver  incisors,  duo  to  dolioiont  anterior  dovolopmont. 
(Norman  G.  Bennett.) 

crowns  of  the  teeth  are  anterior  to  the  apices 


provided  for  thek  accommodation,  they  must  |  to  an  abnormal  extent  and  give  the  appearance 


100 


of  protrusion.  It  should  be  understood,  how- 
ever, that  the  apices  of  the  teeth  are  really 
more    misplaced    than   the    crowns ;    the    con- 


rotation,  so  that  the  lingual  surface  of  the 
lateral  overlies  the  labial  surface  of  the  central 
(see  Figs.  159,  160,  161).  In  such  cases  there  may 
be  sliglit  rotation  of  the  cen- 
trals in  either  direction,  with 
approximation  of  their  labial 
or  Ungual  surfaces  (see  Figs. 
162,163).  In  the  former  vari- 
ety, wlien  the  rotation  of  the 
centrals  is  at  all  considerable, 
the  laterals  are  often  placed  on 
a  posterior  plane,  so  that  the 
lingual  surface  of  each  central 
overlies  the  labial  surface  of 
the  adjacent  laterals.  In  other 
cases  the  laterals  are  on  a 
plane  anterior  to  the  centrals, 
and  have  their  distal  surfaces 
rotated  forwards  (see Fig.  164). 
When  the  degree  of  lingual 
malposition  (postplacement)  is 
extreme,  all  four  incisors  may 
occlude  behind  the  lower 
incisors.  It  is  probable  that 
this  is  most  likely  to  occur 
when  the  deciduous  upper 
incisors  and  canines  are  all 
lost  prematurely,  so  that  in  the 
limited  space  afforded  by  im- 
perfect bony  development,  the 
incisors  are  able  to  encroach 
freely  on  the  portion   proper 

Fig.  100. — Rotation  of  upper  lateral  inci-sors  and  Ungual  displacement  of  to  the  permanent  Canines,  and 
lower  lateral  incisors,  due  to  deficient  anterior  development.  (Haroi.d  are  not  forced  to  take  up  a  V- 
CHAPM-iN. )  shaped  alignment  or  to  overlap 

dition  is    one  of  proclination,   rather  than  of!    one  another  (see  Figs.  165,  166,  167,  168,  169). 

undue  advancement  of  the  whole  tooth.  '        Of  course  modifications  of  these  conditions 

In  other  cases  the  central  incisors    take    up      arise,    but   most   cases   approach   more   or   less 


Fig.  161. — Typical  case  of  rotation  of  lateral  incisors 
and  overlapping  of  centrals  by  laterals,  due  to 
slightly  deficient  anterior  development  in  other- 
wise well-formed  arch.     (Harold  Chapman.) 

a  nearly  normal  position  relatively  to  one 
another,  but  are  really  placed  too  far  lingually 
and  encroach  on  the  space  for  the  laterals. 
When  these  erupt  the  crowns  wiU  be  deflected 
forwards  and  there  will  be  a  certain  amount  of 


Fig.  162. — "  Reverse  "  rotation  of  central  incisors  due  to 
deficient  anterior  development.  (Norman  G.  Bennett.  ) 

closely  to  these  type  forms.  The  position  finally 
taken  up  by  the  upper  incisors  is,  of  course, 
partly  controlled  by  the  development  of  the 
mandible  and  the  position  of  the  lower  incisors. 


101 


In  tlie  mandible  the  conditions  of  develop- 
ment are  different.  The  permanent  teeth  erupt 
usually  on  the  lingual  aspect  of  the  deciduous 
arch,  and  are  translated 
forwards  (probably  by  the 
action  of  the  tongue).  If 
the  growth  of  bone  has  pro- 
vided insufftcient  space  for 
the  centrals,  and  the  de- 
ciduous laterals  are  still  in 
position,  this  forward  move- 
ment will  be  prevented  (see 
Fig.  170).  The  laterals  will 
then  probably  erupt  later 
labially  to  the  centrals  and 
will  overlap  them.  If,  on 
the  other  hand,  the  centrals 
are    able    to    move    forward, 


lap  and  override  the  deciduous  canines,  but  the 
apices  remaui  in  the  contracted  space  occasioned 
by  insufficient  bony  development  and  the  typical 


Fig.  103. — Slight  •■  reverse  "  rotation  of  central  incisors. 
(Harold  Chapman.) 

on  account  of  loss  of  the  deciduous  laterals, 
as  often  happens,  then  they  take  up  a  nearly 
normal    ])osition.    except    that    they    may    be 


Fig.  1(J4. — Postplacemcnt  of  the  upper  central  incisors  and  all  lower  incisors  and 
slight  "  reverse  "  rotation  of  upper  laterals,  due  to  deficient  anterior  develop- 
ment.     (G.  NORTHCROFT.) 

placed  somewhat  too  far  lingually  and  their 
apices  are  too  close  together.  The  crowns  of 
the  laterals  as  they  erupt  will  then  be  forced 
lingually  (see  Figs.  176,  223) ;  or  they  may  over- 


FlG.  J  65. — Slight  postplacement  of  upper  central 
incisors  (normal  occlusion  of  molars).  (Harold 
Chapman.) 

fan-shaped  condition  is  produced.  It  should  be 
noted  that  this  fan-shaped  arrangement  does  not 
at  all  necessarily  involve  any  excessive  degree  of 
eruption  and  occlusion 
behind  the  cingula  of  the 
uppers,  which  is  a  distinct 
phenomenon.  A  some- 
what similar  appearance 
is  occasionally  seen  in  the 
upper  incisors.  The  ulti- 
mate position  of  both 
iipjjer  and  lower  teeth 
is  influenced  by  the  oc- 
clusion, and  the  abnor- 
malities in  each  jaw  react 
on  the  position  of  the 
teeth  in  the  other.  It 
may  be  said  that  in  the 
mandible  rotation  is  far 
less  frequently  adopted 
by  the  erupting  teeth  under  the  pressure  of 
external  forces  than  in  the  pre-maxilla,  because 
in  the  lower  incisors  the  labio-lingual  diameter 
more  nearly  approaches  the  medio-distalthan  in 


102 


the  upper.      The  shape  of   the  lower  incisors 
favours   overlapping    of    two    or    more    teeth 


sufficient  to  remedy  the  cause  of  the  evU,  and 
it  is  of  prime  importance  that  growth  of  bone 
should  be  stimulated  by 
attention  to  general  health, 
physical  exercises,  and 
rational  methods  of  feed- 
ing. 

In  the  cases  of  lingual 
malocclusion  of  the  four 
upper  incisors,  premolar 
and  molar  occlusion  bemg 
normal,  a  forward  move- 
ment of  the  roots  will  not 
usually  be  necessary  if  the 
position  of  the  crowns  has 
been  corrected  at  a  fairly 
early  age — before  twelve 
according  to  Case ;  when 
necessary  it  may  perhaps 
best  be  accomplished  by 
means  of  the  contouring 
apparatus  of  Case,  to  be 
referred  to  again  subse- 
quently. 

Some  authors  (52,  p.  81) 
(54)  recommend  tliat  iii 
cases  of  this  kind  the 
anterior  teeth  should  not 
be  translated  labially  but 
only  corrected  as  regards 
their  alignment,  and  that 
^  in    order   to    prevent  the 

Fig.  166.— Postplacement  of  upper  incisors  (lingual  occlusion),  and  secondary  subsequent  development 
inferior  protrusion.  For  details  of  treatment  of  this  case  and  figure  showing  O'-  ^"^  kmd  01  aunormall- 
results  see  p.  244;  Figs.  374,  375,  376,  377.     (Norman  G.  Bennett.)  ties  shortly  to  be  described, 

(imbrication),  and  more  or  less  complete  labial  or 
luigual  displacement,  or  spreading  of  the  crowns 
and  overlapping  of  the  deciduous  canines  by  the 
permanent  laterals  (see  Figs.  171,  159.  160). ^ 

Treatment. — The  treatment  of  these  conditions 
should  be  commenced  at  once.  The  crowns 
of  the  misplaced  teeth  should  be  reduced  by 
mechanical  means  to  their  proper  positions, 
so  that  sufficient  space  will  be  provided  for 
the  eventual  eruption  of  the  permanent  canines. 
The  effect  of  this  movement  of  the  crowns  will 
be  to  produce  an  appearance  of  protrusion, 
really  proclination  (especially  of  the  upper 
teeth),  because  the  roots  remain  in  an  abnorm- 
ally lingual  position.  If,  however,  development 
proceeds  subsequently  on  normal  lines  this 
error  wiU  to  a  large  extent  be  corrected  by 
growth,  which  may  be  supplemented  bj' 
mechanical  means.  But  it  should  be  under- 
stood that  mechanical  treatment  is  not  alone 

'  J.  F.  Colyer  has  illustrated  excellent  examples  of 
dried  specimens  showing,  as  the  result  of  defective  bony 
growth,  abnormal  positions  of  the  teeth  in  their  crypts,      (-u_    f„„„    „„„„...  i    j  i  i        ii     i 

such  as  would  naturally  develop  into  the  forms  of     Y"^  /°?''   unerupted  premolars   should   be   ex- 

abnormalitydescribed  above  (Zienta/ i?e,corrf,  Feb.  1914,      tracted.      It    LS    possible    that    in     Some     CaseS 

P-  112).  where  there  is  disproportion  between  the  size 


103 


of  the  teeth  and  the  individual  physique,  or  ,  an  age.  If  extraction  proves  necessary  later, 
where  it  is  improbable  that  later  physical  i  the  results  need  not  be  inferior  to  those  pro- 
development  will  compensate  for  early  mal-  j  duced  by  extraction  of  the  unerupted  premolars, 
nutrition,    this    method    may    be    the    correct        2.  Conditions  arising  or  further  developing  after 

loss  of  the  deciduous  molars. 

It  is  obvious  that  if  the  space 
proper  to  the  permanent  canine  has 
been  encroached  upon  by  the 
iiicisors,  and  if  the  deciduous  canine 
has  not  been  translated  forwards 
and  outwards  by  interstitial  bony 
growth,  the  space  necessary  for  the 
teeth  intervening  between  the  in- 
cisors and  first  molars  wUl  be 
insufficient.  Therefore,  deformities 
similar  in  appearance  to  tliose  pro- 
duced by  premature  loss  of  the 
deciduous  molars  and  forward  translation  of  the 
permanent  molars  will  be  produced.     It  is  impor- 


FlG.  168. — Postplacement  of  upper  incisors,  unerupted 
canines,  normal  occlusion  of  molars,  lingual 
occlusion  of  second  upper  premolars.  (Norman 
G.  Bennett.) 


Fig.  170. — Lingual  displacement  of  right  central 
incisor,  deciduous  laterals  still  in  position,  due  to 
deficient  anterior  development.     (J.  H.  Badtock.) 


Portrait  of  case  shown  in  Fiji 


one  to  pursue ;  but  in  the  opinion  of  the  ^^•riter 
sucli  cases  are  not  very  frequent,  and  at  all 
events  considerable  judgement  is  necessary  on 
the  part  of  the  operator  to  determine  the  pro- 
bable course  of  future  development  at  so  early 


Fig.  171. — Imbrication  of  lower  incisors,  lingual 
displacement  of  left  lateral,  right  lateral  over- 
lapping deciduous  canine,  due  to  deficient  anterior 
development.     (Norman  G.  Bennett.) 

tant,  however,  to  bear  in  mind  the  cardinal  diSer- 
ences  between  apparently  similar  cases,  and  to 
distinguish  between  the  abnormality  of  position 
of  a  canine  or  premolar  that  is,  on  the  one  hand, 
due    to    posterior   encroachment,    and    on    the 


104 


other  liand,  to  anterior  encroachment  caused  by 
imperfect  bony  development.  The  two  are 
fundamentally  different,  and  the  treatment  is 
also  different  in  principle  and  detail.^ 


Fig.  172. — Buccal  cli.splaceineiit  of  upper  canines  due  to 
deficient  anterior  development.    (H.^rold  Chapm.4N.) 

The  first  premolar  is  not  usually  much  mis- 
placed, because  sufficient  space  is  retained  for 
it  by  its  equally  large  deciduous  predecessor, 
but  it  is  probable  that  the  transverse  dimension 
between  the  two  first  premolars  is  less  than 
normal,  and  the  arch  somewhat  contracted 
in  the  premolar  region. 

The  tooth  most  frequently  afl^ected  must 
obviously  be  the  canine,  which,  in  such  cases, 
in  the  maxilla  usually  erupts  high  up  on  the 
buccal  side  of  the  alveolus  (less  often  lingually), 
and  never  attains  proper  alignment  with  the 
other  teeth,  although  the  conditions  may  im- 
prove in  tlie  natural  course  of  growth  (.see  Figs. 
172,  173,  174,  175,  141);  in  "the  mandible  it 
may  also  erupt  on  tjie  buccal  or  Imgual  aspect, 
more    frequently    the    former    (see   Fig.    158). 

^  It  should  be  pointed  out,  however,  that  a  form  of 
posterior  encroachment  due  to  deficient  development 
may  occiu".  If  backward  growth  of  the  maxilla  is 
deficient,  the  erupting  first  permanent  molar  may  cause 
absorption  of  the  distal  surface  of  the  second  deciduous 
molar,  and  eventually  take  up  a  position  too  far  forward 
and  reduce  the  space  available  for  the  premolars.  Such 
deficiency  of  growth  is  usually  correlated  with  deficient 
anterior  development  and  malalignment  of  the  incisors 
already  described. 


It  should  be  remembered  that  the  apparently 
erring  tooth  is  often  really  le.ss  out  of  position 
than  its  neighbours. 

The  order  of  eruption  has  less  influence  on 
the  character  of  the  deform- 
ity than  in  the  cases  pre- 
viously described  as  being 
due  to  forward  translation 
of  molars.  If  the  second 
premolars  erupt  before  the 
canine  the  malposition  of 
the  canine  will  the  more 
certainly  be  produced.  If 
the  canine  erupts  first  the 
deformity  produced  will  de- 
pend to  some  extent  on  the 
amount  of  space  available 
for  it.  Where  this  is  quite 
insufficient  the  effect  will  be  as  just  described,  but 
\\here  the  encroachment  has  been  but  small,  the 
force  of  eruption  of  the  canine  may  be  sufficient 
to  move  the  adjacent  teeth.  In  tliis  way,  by  a 
slight  backward  movement  of  the  first  premolar, 
the  second  premolar  may  be  prevented  from 
coming  into  normal  alignment  and  normal  occlu- 
sion with  its  opponent,  and  nnist  erupt  on  the 


Fig.  173. — Buccal  displacomenl  of  right  canine  due  to 
deficient  anterior  development.  {Norman  G. 
Bennett.) 

buccal  or  lingual  aspect,  more  usually  the  latter. 
Malposition  of  a  premolar  from  this  cause  is, 
however,  probably  far  less  common  than  the 
same  abnormality  associated  with  forward 
translation  of  molars  (see  Fig.   176). 

The  teeth  more  frequently  influenced  by  the 


105 


enipting  canine  are  the  incisors.  In  the  case 
of  the  upper  teeth  tlie  two  typical  conditions 
previously  described,  namely,  rotated  centrals, 
or  rotated  laterals  overlapping  the  centrals, 
are  often  accentuated.  But  it  is  very  doubt- 
ful whether  a  typical  laterally  contracted  or  V- 
shaped  arch  is  ever  produced  at  this  period 
unless  there  has  previously  been  a  small  defor- 
mity of  the  kind  (see  Figs.  177,  178,  179). 

The  question  of  the  relative  influences  of 
inheritance  and  environment  in  contributing 
to  this  and  other  conditions  has  already  been 
discussed,  and  although  it  seems  clear  that  the 
active  causes  are  largely  dependent  on  conditions 
of  environment  in  each  generation,  it  is  never- 
theless probable  tliat  inherited  genetic  varia- 
tions form  an  important  factor,  and  at  the  least 
j)redispose  the  individual  to  the  influence  of 
such  external  agencies. 

It  will  be  unclerstood  that  the  displacement 
of  the  canine  is  chiefly  towards  the  median  line 
(although  the  tooth  shows  a  buccal  inclination), 
so  tliat  the  distance  between  the  two  canines 
is  diminished ;  the  premolars  are  not  greatly 
affected,  except  that  they  come  into  line  between 
the  canine  and  first  molar,  and  thus  in  extreme 
cases  the  arcli   of  the  teeth   from   the   central 


the  incisors  will  usually  be  increased  by  the  erup- 
tion of  the  canine,  and  narrowness  of  the  anterior 


Fig.  174. — Postplacement  and  rotation  of  upper  incisors  due  to  very  deficient 
anterior  development.  Post-normal  occlusion  of  lower  molars  and 
mandible,  probably  secondary  to  maxillary  development.  (Norman 
G.  Bennett.) 

mcisors  to  the  second  molars  is  reduced  very 
nearly  to  a  straight  line.     In  a  similar  manner 
in  the  case  of  the  lower  teeth,  imbrication  of 
4* 


Portrait  of  case  shown  in  Fig. 

portion  of  the  lower  jaw  produced  in  this  way  is 
often  associated  with  a  contracted  upper  arch  ;  a 
fan-sliaf)ed  condition  of  the 
lower  incisors  may  be  somewhat 
accentuated  by  the  same  cause. 
The  deformities  described  may 
be  connected  with  (or  in  the 
later  stages  of  their  develop- 
ment be  increased  by)  obstruc- 
tion to  nasal  breathing  from 
adenoids,  or  other  nasal  diseases 
or  deformity ;  but  it  is  probable 
that  such  cases  are  almost 
always  associated  with  abnor- 
mal occlusion  and  relationship 
of  the  two  jaws,  and  constitute 
the  various  forms  of  protrusion 
and  retrusion  to  be  presently 
considered.  The  typical  V- 
shaped  arch,  so-called,  is  not 
necessarily  or  usually  associated 
with  malocclusion  of  the  molars 
and  premolars. 

There    remain    to    be    con- 
sidered  those    cases    m    which 
the  anterior  teeth  are  normally, 
or   nearly  normally,   arranged, 
but  in  which  the  laosterior  teeth 
are  lingually  inclined,  and  the 
upper  arch  exhibits  a  U -shape 
«ith  the  sides  nearly  parallel, 
and  the  lower  shows  a   corre- 
sponding deformity.    It  is  pro- 
bable that  defective  bony  development  is  not  as 
a  rule  the  cause  of  the  evil.    Although  there  is  a 
transverse  narrowness  of  the  arch,  the  reduction 


lOG 


is  rather  of  the  distance  between  the  crowns 
than  the  roots,  and  differs  in  this  respect  from  the 
contracted  palate  associated  with  nasal  stenosis, 
in  which  tlie  vault  is  both  high  and  narrow. 

It  is  possible  that  the  prime  cause  is  smaU- 
ness  and  imperfect  development  of  the  tongue, 
which  allows  the  nniscles  of  the  cheek  to  force 
the  crowns  of  the  teeth  towards  the  median 
line  during  eruption. 


Fio.  17G. — Lingual  dis|jlacement  of  upper  second  premolars  and  lingual  displace- 
ment of  lower  lateral  incisors,  due  to  deficient  development.   (G.  Northcroft.) 

Treatment. — The  treatment   of   cases  of   this 
large   class    is    difficult,   and    requires    careful 
consideration  of  the  causes  that  have  been,  and 
are,  operative.     It  should  be  remembered  that 
the  defect  is  anterior  to  the  first  molars  and 
theoretically  the  correct  treatment  is  to  expand 
the  anterior  portion  of  the  arch  or  arches  and 
reduce   each    tooth    to    correct   alignment   and 
occlusion.     In  simple  cases  this  should  obviously 
be     undertaken  ;     but     in 
cases  where,  for  example, 
the  canines  are  almost  com- 
pletely excluded  from  the 
arch,  and  where  the  bony 
development  in  the  incisor 
region  is  deficient  in  rela- 
tion to  the  teeth,  but  not 
markedly  so  m  relation  to 
the  facial  contour,  so  that 
the  incisors  although  really 
placed  too  far  lingually  do 
not  appear  so  (by  reason  of 
their    proclination),    treat- 
ment by  expansion  on  ideal 
lines  may  result  in  a  pro- 
gnathous  appearance,   be- 
cause the  roots  of  the  incisors  must  be  translated 
labiaUy  as  well  as  the  crowns.     Cases  of  this 
kind  not  infrequently  present  themselves  in  ill- 
nourished  children,  in  whom  there  is  but  little 
hope  of  subsequent  development  making  up  the 
arrears  of  stagnation,  and  providing  the  child 
with  face  and  jaws  in  harmony  with  the  teeth, 
which  are  of  a  normal  size  and  have  calcified 
too   early  to  have    been   subject  to  the  same 
depressing  influence. 


It  then  becomes  necessary  to  extract,  and  the 
general  rule  may  be  laid  down  that  the  canines 
should  scarcely  ever,  if  ever,  be  removed ;  that  the 
laterals  should  be  removed  only  m  a  small  minor- 
ity of  instances ;  that  the  first  premolars  should 
usually  be  selected ;  and  that  extraction  should 
Ije  symmetrical.  In  deciding  between  the  laterals 
and  the  first  premolars  in  tlie  case  of  outstanding 
canines,  attention  should  be  given  to  the  direc- 
tion and  incluiation  of  the 
canines,  because  movement 
of  the  crowns  is  compara- 
tively easy,  and  of  the  roots 
exceedmgly  difficult.  Where 
only  a  small  additional  space 
is  required  the  second  pre- 
molars should  be  selected  in 
J  (reference  to  the  first ;  the 
first  premolars  can  easily 
Ix-  moved  back  sufficiently 
to  allow  the  canines  to 
reach  normal  alignment. 

In   those  cases  in  which 
the  aberrant  tooth  (or  teeth) 
is    a   second    premolar,    it 
should  usually  be  preferred  to  the  first. 

It  has  been  pointed  out  that  cases  of  this 
class  are  not  necessarily  associated  with 
abnormal  occlusion  of  tlie  molars  and  pre- 
molars, and  it  is  for  this  reason  that  extraction 
should  usually  be  symmetrical ;  but  if  the  lower 
teeth  are  in  post-normal  occlusion  with  the 
upper,  and  the  lower  incisors  are  imbricated, 
it  is  often  good  treatment  to  remove  two  upper 


-Proclination 


upper   incisors  increased    by  eruption  of    canines. 
(O.  Northcroft.) 

first  premolars  and  a  lower  incisor,  not  neces- 
sarily selecting  the  one  most  misplaced,  but 
preferring  an  incisor  misplaced  labially  to  one 
misplaced  lingually,  because  the  latter  is  more 
easily  reduced  by  nature  and  art. 

In  some  cases  where  extraction  is  rightly 
practised,  natural  forces  will  in  due  time 
correct  the  deformity,  but  in  the  greater 
number  mechanical  assistance  should  be  pro- 
vided.    In  all  cases  the  operator  should  have 


107 


regard  to  the  state  of  the  teeth  in  respect  to 
caries,  and  select  carious  teeth  for  extraction 
whenever  other  considerations  permit.  It  may 
sometimes  be  advisable  not  to  extract  opposing 
teeth  but  to  choose,  for  example,  a  first  pre- 
molar in  one  jaw  and  a  second  ua  the  other, 
and  move  the  teeth  into  occlusion  mechanically ; 
or  in  other  cases  to  extract  two  first  premolars 
on  one  side  and  two  second  premolars  on  the 
other. 

Cases  frequently  occur  in  which,   if  all  the 
teeth  were  sound,  the  first  premolars  would  be 


Fig.  its. 


Fig.  179. 


Fig. 


178  from  casts  at  10  to  11  years  of  age ;  Fig.  179 
at  13  to  14  years  of  age.  Note  the  change  in  the 
form  of  the  arches  produced  by  pressiu'e  diu'ing 
the  eruption  of  the  canines  and  second  premolars. 
In  Fig.  178  the  left  upper  lateral  is  in  lingual 
occlusion.  In  Fig.  179  the  left  upper  premolars 
are  in  lingual  occlusion,  and  also  the  first  molar, 
which  was  normal  before.  The  arch  has  become 
narrowed  ^'/j  of  an  inch.  (F.  A.  Gocgh  :  Dental 
Cosmos.) 


chosen  for  extraction,  but  in  which  some  or 
all  of  the  first  molars  are  extensively  carious 
or  even  abscessed.  The  only  treatment  then 
possible  is  to  extract  the  molars  and  move 
back  the  premolars,  but  a  certam  amount  of 
backA\ard  inclination  of  the  premolars  usually 
remains,  and  is  difficult  to  remedy. 

It  is  clear  tliat  where  so  many  factors  requu'e 
consideration,  nice  judgement  is  needful  in 
determining  the  best  course  of  treatment,  and 
it  is  impossible  to  do  more  than  lay  down  the 
general  principles  by  which  the  operator  should 
be  guided. 


[  CLASS   III.— Abnormal   Relationship   between    the 
j  Upper  and  Lower  Arches  and  between  either 

Arch  and  the  Facial  Contour,  and  Correlated 
j  Abnormal  Formation  of  either  Arch,  due  to 

[  Developmental  Defects  of  Bone 

The  particular  types  of  abnormal  position 
of  the  teeth  so  far  considered  have  been  those 
hi  \^hich  the  relationship  of  the  two  arches  is 
not  necessarily  involved.  The  abnormalities 
may  occur  in  one  or  both  arches  and  errors  of 
occlusion  may  in  consequence  often  exist,  but 
the  malocclusion  is  as  a  rule  local  and  limited 
to  the  particular  portion  of  the  arch  in  which  the 
teeth  are  misplaced. 

In  the  cases  now  to  be  considered  there  is 
an  abnormal  relationship  between  the  arches 
involving  the  whole  arch,  or  at  least  a  large  part 
of  it,  and  the  malocclusion  is  not  the  result  of 
misplacement  of  individual  teeth,  but  rather 
of  more  deep-seated  causes  of  a  developmental 
kind.  In  fact  the  question  of  occlusion  becomes 
of  fundamental  importance  in  connection  with 
cases  of  this  class,  and  credit  is  due  to  Angle 
for  his  insistence  on  its  value  as  a  diagnostic 
factor.  In  the  opinion  of  the  writer,  Angle  goes 
too  far  m  making  it  almost  the  sole  basis  of  classi- 
fication of  malposition  of  the  teeth,  and  Case  is 
right  m  emphasizing  the  need  to  consider  not 
only  the  relationship  of  the  two  arches  but  also 
the  relationship  of  each  arch  to  the  facial  contour. 

It  Ls  clear  that  abnormality  of  the  relationship 
of  the  arches  may  be  of  three  kinds  :  (1)  Vertical, 
(2)  Antero-posterior,  and  (3)  Lateral. 

1.— VERTICAL 

When  the  teeth  occlude  normally  the  upper 
and  lower  mcisors  overlap,  so  that  about 
one-third  of  the  lower  incisors  is  concealed 
by  the  uppers,  and  the  edges  of  the  lowers 
occlude  with  that  portion  of  the  upj)er  incisors 
that  is  commencing  to  thicken  to  form  the 
cingulum.  Variation  in  the  amount  of  this 
overlap  may  occur  in  either  direction,  and  the 
question  at  once  arises,  whether  the  abnormality 
exists  m  that  part  of  the  arch  where  it  is  most 
apparent,  namely,  the  anterior  portion,  or  whe- 
ther the  posterior  region  is  also  mvolved. 

It  is  probable  that  in  a  few  cases  the  defect 
occurs  in  connection  with,  and  is  reaUy  limited  to, 
the  incLsor  region  only ;  but  undoubtedly  in  most 
cases  the  bony  development  of  the  ascendmg 
ranius  or  angle  of  the  mandible  or  posterior  por- 
tion of  the  maxilla  is  at  fault,  and  the  anterior 
defect  is  a  necessary  consequence.  Li  some  of 
the  latter  it  is  clear  that  secondary  changes 
occur  later  in  the  development  of  the  incisor 
region,  and  produce  conditions  that  simulate 
cases  of  malformation  due  to  difi'erent  causes. 

(«)  Open  Bite. — The  extent  to  which  the  teeth 
fail    to    occlude    may    vary    between    a    small 


lOS 


separation  of  the  incLsors  and  a 
which    only    the    second    molars 


condition  in 
occlude.     In 


Fig.  180. — Open  bite.  Tlie  only  teath  that  occlude  are  the  second  left  molars. 
On  the  right  side  the  second  molars  have  moved  forward,  especially  tlie 
upper.  For  the  interesting  result  of  treatment  of  this  case,  and  figures, 
seep.  244;   Figs.  371,  372,  373.     (Norman  G.  Bennett.) 

a  typical  case  abnormal  development  of  the 
mandible  is  very  apparent ;  the  ascending 
ramus  is  short  and  the  angle  unduly  oblique. 
It  is  easy  to  understand  that  if  the  depth  of  the 
mandible  and  height  of  the  molar  teeth  in  both 
jaws  are  normal,  the  effect  of  a  short  ascending 
ramus  nuist  be  to  produce  an  open  condition 
anteriorly,  and  the  obliquity  of  the  angle  is  a 
necessary  concomitant.  Curiously  enough  the 
anterior  portion  of  the  mandible  presents  in 
different  cases  exactly  opposite  conditions. 
Sometimes  there  is  deficient  development,  and 
sometimes  excessive  growth  of  chin  together 
with  an  apparent  bending  at  the  anterior  border 
of  the  insertion  of  the  masseter  muscle  ^  (see  Figs. 
180,  181,  182). 

Deficient  development  occurs  also  in  the 
anterior  portion  of  the  maxilla  and  in  the  pre- 
maxilla,  and  in  either  jaw  is  not  very  difficult 


1  Rushton  considers  tliat  this  difference  is  associated 
with  antero-posterior  malocclusion,  and  depends  upon 
whether  the  mandible  is  retruded  or  protruded.  In  the 
former  case  tliere  would  be  deficient  anterior  develop  - 
ment,  and  in  the  latter  excessive  growth. 


to  understand,  because  failure  to  occlude 
involves  loss  of  function,  or  at  least  diminished 
function  ;  that  is  to  say,  the  an- 
terior defect  is  probably  secon- 
dary to  the  posterior.  It  might 
be  expected  that  the  incisor 
teeth  would  continue  to  erupt 
on  account  of  the  failure  to 
occlude,  but  it  is  probable  that 
the  belief  in  this  tendency  of 
teeth  to  be  raised  in  their 
sockets  until  they  meet  their 
fellows  has  little  foundation  in 
fact.  It  is  extremely  difficult 
to  produce  this  result,  at 
any  rate  permanently,  when 
desu'ed,  in  the  case  of  molars, 
as  wiU  presently  be  seen,  and 
it  is  probable  that  the  extni- 
sive  force  of  eruption  ceases 
after  complete  formation  of 
the  roots  of  teeth.  The  eleva- 
tion from  its  socket  of  a  tooth 
that  has  no  oi3j)osing  teeth  in 
later  life  is  of  a  different  char- 
acter ;  it  is  associated  with 
alveolar  absorption  rather  than 
with  the  deposit  of  bone  that 
accompanies  normal  eruiJtion. 
It  is  doubtful  whether  cases 
of  open  bite  caused  by  de- 
fective anterior  development 
in  otherwise  normal  jaws  ever 
occur.  Such  apparent  examples 
are  usually  due  to  external 
conditions — e.  g.  thumb-suck- 
ing—  and  should  not  be  con- 
fused with  cases  of  the  type  now  under  con- 
sideration.   The  excessive  growth  of  the  mental 


Fig.   181. — Portrait  of  case  shown  in  Fig.  180. 

portion  of  the  mandible  and  the  apparent  bend- 
ing is  difficult  to  understand ;  an  excellent  ex- 
ample is  figured  in  Tomes  and  Nowell  (153).    It 


109 


is  indeed  doubtful  whether  the  anterior  growth 
is  excessive  absohitely,  or  only  relatively  to 
deficient  posterior  growth. 

It  has  been  suggested  that  the  bending  takes 
place  as  the  result  of  muscular  action,  the  anterior 
portion  being  pulled  down  by  the  depressor 
muscles  of  the  chin  ;  there  is  no  evidence  to 
show  whether  this  occurs,  but  it  is  possible 
that  in  the  course  of  development,  if  the  anterior 
teeth  fail  to  occlude,  the  depressor  nuiscles  will 
naturally  become  accommodated  to  the  condi- 
tion and  retain  the  anterior  jJortion  of  bone  in 
that  position,  whOe  the  powerful  masseter 
muscle  will  be  constantly  acting  in  an  opposite 
direction  in  endeavouring  to  produce  complete 
closure,  and  will  induce  deposits  of  boiie  about 
its  insertion.  It  should  be  remembered  that 
the  function  of  the  bone  of  the  mandible  is  to 
support  the  teeth  and  afford  insertion  for  muscle. 
It  is  probable  that  some  explanation  of  the  kind 
is  not  very  far  from  the  truth,  but  it  should  be 
distinctly  understood  that  the  condition  requires 
further  elucidation. 

Many  if  not  most  cases  of  open  bite  mal- 
occlusion are  associated  with  adenoids  and 
mouth-breathing,  and  in  them  the  palate  is 
narrow  and  has  a  high  vault  (56).     The  prime 


183).  It  is  not  altogether  easy  to  see  how  a  highly 
vaulted  palate  will  produce  open  bite,  because 
the  increased  height  is  upwards  in  the  centre 
rather  than  down\^ards  at  the  sides,  and  is  due 


r^'x 


/ 


Fig.   182. — Open  bite  with  nearly  normal  arches.      (B.  E.  Lischer  :  Dental  Cosmos.) 


cause  of  the  open  bite  seems  then  to  reside  in  the 
maxilla  rather  than  the  mandible,  which  may  be 
normal  or  nearly  so,  but  is  usually  naiTOw  with 
lingually  inclined  molars  and  premolars  (see  Fig. 


Fig.  183. — Open  bite  with  imiihv    arches.      (A.  P. 
Rogers  :  Dental  Cosmos.) 

to  defective  nasal  expansion.     But  the  narrow- 
ness is  probably  associated  with  increased  depth 

in  the  molar 
region ;  it  should 
be  remembered 
that  the  upper 
molars  have  nor- 
maUy  a  buccal 
inclination, 
whereas  in  the 
narrowed  arch  the 
axes  of  the  molars 
of  the  two  sides 
approach  parallel- 
ism. The  effect  of 
this  must  be  in- 
creased depth, 
which  nuist  have 
the  same  result  in 
producing  lack  of 
occlusion  of  the 
anterior  teeth  as 
shortness  of  the 
ascending  ramus 
of  the  mandible. 

Defective  de- 
velopment around 
the  upper  incisor 
teeth  is  very  fre- 
(juently  associ- 
ated with  these 
cases,  probably 
more  often  than  in  the  cases  where  the  mandible 
is  chiefly  at  fault.  The  cause  may  be  found  in 
loss  of  function,  but  it  has  been  noticed  that 
examples   associated    with   narrow  palate   and 


W^ 


:/ 


■^ 


110 


nasal  stenosis  often  exhibit  hypoplasia  of  enamel, 
and  the  inference  is  obvious  that  early  mal- 
nutrition lias  been 
the  origin  of 
several  defective 
conditions  of  de- 
velopment whose 
interaction  results 
in  phenomena  not 
easily  traced  in 
every  detail  (see 
Figs.  184,  185, 
186,  187). 

It    is     possible 
that  the  constant 


this  uifluence,  while  the  anterior  portion  of  the 
mandible  is  kept  depressed  by  the  hyo-mandi- 

bular  muscles,  the 
posterior  portion 
is  constantly 
forced  upwards  by 
the  masseter  and 
internal  pterygoid 
muscles,  and  so 
the  obliquity  of 
angle  associated 
M'ith  the  early 
years  of  life  is 
maintained.  It 
will  be  perceived 


Fig.     184. 


-Open     bite    associated    with   liypoplasia,    anterior    gingivitis,    adenoids    and    small    pharynx. 
Normal  molar  occUision.     (Norman  G.  Bennett.) 


185. — Portraits  of  case  shown  in  Fig.  184. 


habit  of  mouth-breathing  consequent  on  nasal  I  that^  this  explanation  is  practically  the  same 
stenosis  may  be  the  initial  cause  of  open  bite.  I  in  its  method  of  action  as  that  offered  above 
esaC,  in  1894,  advanced  the  view  that  under  |   for  the  bending  of  the  mandible.     At  present 


Ill 


it  is  impossible  to  say  whether  the  obliquity 
of  angle  and  shortness  of  ascending  ramus  are 
consequent  on  mouth-breathing  and  muscular 
action ;  or  whether  deformation  of  the  horizontal 
ramus  is  secondary  to  shortness  of  ascending 
ramus  or  increased  depth  of  maxilla  or  both, 
and  mouth-breathing  only  the  natural  con- 
comitant of  the  nasal  stenosLs  that  causes  the 
narrow  and  deep  maxilla.  J.  Sim  Wallace  (162) 
advances  the  view  that  the  obliquity  of  angle  is 
caused  by  insufficient  use  of  the  masseter  and 
internal  pterygoid  muscles  m  mastication,  associ- 
ated with  an  abnormally  posterior  position  of 
both  arches  due  to  insufficient  use  and  develojD- 
ment  of  the  tongue  in  mastication.  He  points 
out  that  in  a  well-developed  jaw  the  mandible 
is  widened  and  everted  by  deposition  of  bone 
around  the  insertion  of  the  masseter  at  the 
angle,  and  along  the  lower  and  outer  border, 
and  that  where  function  is  deficient  the  obliquity 
normal  to  infancy  is  maintamed ;  in  that  case 
the  second  lower  molar  erupting  behind  the 
already  retruded  arch  must  find  room  for  its 
eruption  by  a  raising  of  the  alveolus,  and 
anterior  open  bite  is  the  necessary  result.  Sim 
Wallace  states  that  the  condition  usually 
develops   rapidly   at   the   time   of   eruption   of 


period,  consequent  on  discomfort  attendant  on 
eruption  of  the  molars.     He  believes  that  rapid 


Fio.  186. — Open  bite  associated  with  hypoplasia.    Molar  occlusion 
lower  post-normal  half  a  unit.     (Gorman  G.  Bennett.) 

the  second  molars,  and  he  associates  this  with  a 
rapid  development  of  the  tongue,  occasioned 
by    its    excessive    use    in    mastication    at    this 


Fig.  187. — Portrait  of  case  shown  in  Fig.  186. 

growth  of  the  tongue  may  produce  open  bite 
apart  from  other  conditions.  It  may  be  said 
that  part  of  Sim  Wallace's  explanation 
appears  to  be  rather  far-fetched,  because 
as  a  rule  the  eruption  of  the  second 
molars  gives  rise  to  little  or  no  incon- 
venience, and  that  his  explanation 
involves  a  rather  curious  alternation  of 
deficient  and  excessive  masticating 
function  at  different  periods  ;  but  there 
is  probably  much  truth  in  his  view  as  to 
the  obliquity  of  the  angle  being  primarily 
dependent  on  diminished  function. 

An  interesting  and  plausible  theory 
of  the  cause  of  open  bite  has  been  put 
forward  by  Van  Broadus  Dalton  (65). 
He  ascribes  the  condition  to  undue 
retention  of  the  deciduous  molars.  He 
];oints  out  very  rightly  that  the  height 
of  the  bite  is  normally  fixed  and  con- 
trolled by  the  first  permanent  molars 
during  the  period  when  the  premolars 
are  erupting,  and  shows  by  examples 
that  when  a  deciduous  molar  is  retained 
it  is  often  forced  in  an  occlusal  direction 
by  the  premolar  erupting  vertically 
l)eneath.  In  this  way  the  bite  is  propped 
open  and  the  permanent  molars  con- 
tinue to  erupt  as  far  as  the  level 
abnormally  created.  The  cases  illus- 
trated by  Dalton  are  very  convincing 
as  far  as  they  go ;  but  much  diversity 
of  form  exists  in  open  bite,  and  although 
this  is  probably  one  cause,  it  can  scarcely  be 
held  accountable  for  all  or  even  a  majority  of 
examples  (see  Figs.  188,  189). 


112 


It  must  be  admitted  tliat  tlie  question  of  the 
aetiology  of  open  bite  is  at  present  ^vTapped  in 
obscurity.  Some 
excellent  ex  - 
amples  of  open 
bite  are  figured  by 
Alfred  P.  Rogers 
(138),  but,  ill  the 
opinion  of  tlie 
wTiter,  it  would 
be  better  not  to 
class  together 
cases  due  to  ex- 
ternal causes,  such 
as  thumb-sucking, 
with  conditions 
caused  by  de- 
velopmental de- 
fects of  tongue  or 
teeth. 

Open  bite  is  not 
necessarily  asso- 
ciated with  any  abnormal  antero- 
posterior relation  of  the  jaws,  but 
as  a  matter  of  fact  a  pre-normal 
position  of  the  lower  molars  in  re- 
lation to  the  upper  is  very  coinmon. 
An  example  is  described  by  Hedley 
Visick  (160).  Case  offers  the  ex- 
planation that  deficient  maxillary 
development  occasions  a  posterior 
position  of  the  upper  molars,  and 
that  mouth-breathing,  by  causing 
the  mouth  to  be  kept  habitually 
slightly  open,  carries  the  mandible 
forwards,  and  that  if  the  effect  of 
these  two  factors  is  to  cause  the 
cusps  of  the  lower  molars  to  occlude 
a   little   in    front    of    their    normal 


cusps.    In  other  examples  open  bite  is  associated 
with  post-normal  occlusion  of  the  lower  molars. 


Fig.  189. — Open  bite  produced  by  undue  reten- 
tion of  second  upper  deciduous  molars.  (Vau 
Broadus  D.4XTON  :   Items  of  Interest.) 


Fig.  1S8. — Open  bite  produced  by  undue  retention  of 
second  upper  deciduous  molar.  (V.4N  Bkoadus 
Dalton  :  Items  of  Interest.) 

inter-digitation,  the  condition  will  be  increased 
and  then  maintained  by  the  interaction  of  the 


A  curious  ex- 
ample of  open 
bite  developing 
at  the  age  of 
about  22  has 
been  descril^ed 
by  J.  H.  Bad- 
cock  (16).  It 
appeared  to  be 
due  to  elonga- 
tion of  the  pos- 
terior  lower 
teeth  c  o  11  s  e  - 
quent  on  ten- 
derness and 
disease. 

Treatme7it. 
The  treatment 
of  open  bite  is  usually  difficult,  and  in  many 
eases  amelioration  rather  than  cure  is  all  that 
may  be  expected.  The  object  to  be  attained 
is  to  restore  the  occlusion  of  the  anterior 
teeth,  and  it  is  obvious  that  this  may  be 
effected  by  extrusion  of  the  anterior  teeth, 
or  by  intrusion  or  reduction  in  height  of  the 
posterior  teeth. 

The  former  method  should  as  a  rule  only  be 
relied  upon  in  cases  where  the  deformity  is  not 
excessive ;  it  is  accomplished  by  means  of 
elastic  ^^■ire  bows  around  the  upper  and  lower 
teeth  connected  togetlier  by  rubber  ligatures. 
The  force  applied  to  tlie  lower  front  teeth  may 
be  assisted  by  occipital  force. 

Occipital  force  applied  by  means  of  skull-  and 
chin-caps,  the  direction  of  the  force  being 
arranged  as  vertically  as  possible,  is  also 
useful  in  cases  of  slight  deformity,  or  in  com- 
bination with  other  methods  of  treatment ;  it 
\\-as  successfully  used  in  a  pronounced  case  by 


113 


F.  Heiickeroth  (92)  as  long  ago  as  1892.  It 
is  especially  ajjplicable  when  the  lower  teeth 
are  in  pre-normal  occlusion  with  the  upper, 
but  should  not  generally  be  used  when  the 
lower  teeth  are  in  post-normal  occlusion.  The 
effect  is  probably  to  drive  the  molars  into 
the  bone  and  they  are  very  apt  to  rise  again 
unless  treatment  is  maintained  for  a  ' 
period. 


long 


grnidmg  down  affords  no  prospect  of  cure  it  may 
be  necessary  to  extract  the  second  molars.  In 
many  cases,  however,  the  second  molars  are 
sound  and  the  first  molars  extensively  carious. 
The  best  treatment  then  is  usually  to  extract 
the  first  molars;  the  second  molars  will  then 
move  forwards  (or  may  be  moved)  to  a  crreat 
extent  into  the  position  of  the  first  molars,  wliere 
there  is  more  vertical  space  for  their  accoinmoda- 


Fio.    190. — Close  bite,   pronounced  overbite   ut  nicisors,  and  retroclinatiuu  uf  uppers.     Jlaudible  post-normal. 
The  daughter  of  tliis  patient  is  shown  in  Figs.  234,  235.     (Xorman  G.  Bennett.) 


In  all  severe  cases  it  is  advisable  to  reduce 
the  height  of  the  second,  and  if  necessary  the 
first  molars,  by  grinding  down  the  cusps.  Only 
a  little  should  be  removed  at  a  time.  If  the 
dentine  is  reached,  silver  nitrate  should  be 
applied  after  the  operation,  and  an  interval 
of  three  or  four  weeks  should  elapse  between 
the  visits,  during  which  the  patient  should 
apply  spirits  of  wine  twice  a  day  to  the  dried 
surfaces  of  the  teeth.  In  this  way  the  pain- 
fulness  of  the  process  is  minimized  and  the 
deposition  of  secondary  dentine  is  encouraged. 
If  necessary  the  upper  molars  should  be  devital- 
ized.    If  the  degree  of  openness  is  so  great  that 


tion,  and  a  certain  amount  of  grinding  down  at 
a  later  date  will  probablv  effect  a  cure.  (See 
p.  244,  and  Figs.   371,  372,  374.) 

It  has  been  said  above  that  many  cases  of 
open  bite  are  associated  with  adenoids,  enlarged 
tonsils,  and  nasal  stenosis.  These  conditions 
of  course  demand  treatment ;  and  the  expansion 
of  the  upper  arch,  and,  if  necessary,  the  lower 
arch  sufficiently  to  produce  normal  occlusion, 
\^ill  improve  the  bite,  because  buccal  movement 
of  the  upper  molars  effects  a  relative  shortening. 
It  has  also  been  remarked  above  that  in 
some  ca.ses  a  proclination  of  the  upper  incisors 
supervenes  on  the  lack  of  occlusion ;    this  can 


114 


often  be  remedied  by  mechanical  means,  and 
where  the  teeth   are  not  markedly  short  the 


Fio.  I'.M.  ('lipHii  liilci  (uul  HcH'dMilary  prdi'liiial  inn  of  u|i|ii'r  iiicisorH,  duo  to 
di'licicnl'  |)(isU'n<ir  unil  vcrtiudl  growl.li  of  luaiidihlo  {mh'  \''in».  192,  193). 
All. Iiif  mill  iiri'iiioliir  orclusiiiri  niirriial.      (N'iirni\N   (',.    lii:N  m;  i  i.) 


judicious  combination  being  usually  the  most 

effective. 

(b)  Close  Bite. — Aii  undue 
amount  of  overlapping  of  the 
incisor  teeth  may  conceivably 
be  due  to  extra  length  of  the 
incLsor  teeth,  upper  or  lower, 
or  to  diminished  depth  in  the 
molar  region. 

A  nterior  Dejormily. — Cases 
that  arc  apparently  of  the  first 
kind  are  those  of  so-called 
parrot  bite,  in  which  the  lower 
incisors  disappear  behind  the 
upper  in  complete  closure.  It 
is  impossible  to  say  whether 
this  condition  is  associated 
with  posterior  deficiency,  but 
the  uj)per  incisors  appear  to 
be  unduly  extruded,  and  the 
crowns  are  usually  somewhat 
retruded,  the  roots  being 
rather  prominent.  The  con- 
ditif)ri  appears  to  be  often 
hereditary ;  Choquet  descri))es 
it  in  his  own  person  and  states 
that  it  occurs  in  four  genera- 
tions in  his  family.  The  writer 
also  has  experience  of  a  case  in 
which  the  deciduous  incisors 
of  a  child  of  five  years  closely 
resemble  in  alignment  and 
appearance  the  permanent 
incisors  of  the  mother  ;  in  both 
there  is  .also  post-normal  oc- 
clusion of  \\\v  lower  arch  {.see 


Kid.    192. 


'nr'tniils  lit  cHSr  hIiowii  in  Ki 


treatment  docs  nuicli  to  restore  nonual  occlu- 
sion. It  is  only  raicly  thai  a  single  method  of 
treatnicnl  sIkhiM   he  adopted  for  tJicse  cases,  a 


Figs.  I!l(),l!;{4  ;uid  2.'!.")).  An  excellent  example 
of  the  deformity  is  figured  by  Alfred  P.  Rogers 
(138). 


115 


Treatment. — In  slight  cases  no  treatment  is 
called  for,  but  in  those  where  the  condition  is 
marked  it  may  be  remedied  by  raising  the  bite 
of  the  posterior  teetli,  and  this  can  best  be  done 
by  covering  the  deciduous  molars  while  these 
are  still  in  place,  and  allowing  the  first  permanent 
molars  to  erupt  more  fulh^  if  they  will. 

Posterior    Deformity. — In     other    cases    the 
cro\^ns    of    the    upper    incisors    exhibit    pro- 
clination,  and  the  lower  incisors  occlude  with 
or  behind  the  cingula  of  the 
upper.      The     condition     is 
clearly  due  to  defective   de- 
velopment in  the  molar  region 
and  at  the  angle  of  the  man- 
dible.   Paradoxically  there  Ls 
a  certain  resemblance  to  the 
form  of  mandible  that  occurs 
in  connection  with  open  bite  ; 
the  ascending  ramus  is  short 
and  the  angle  may  be  some- 
what oblique.     The  difference 
between  the  two  is  apparently 
in    the   development   of    the 
horizontal     ramus     and     the 
height  of  the  molars.  Patients 
exhibiting  this  form  of  close 
bite    are    usually    of    slender 
build,    and   the   body   of   the 
mandible  is  shallo\v  and  the 
molars  are  short.     In   spite, 
therefore,  of  the  shortness  of 
the  ascending  ramus  the  molar 
occlusion   causes   no   unpedi- 
ment  to  incisor  occlusion  but 
even  allows  it  to  an  excessive 
degree.    As  a  consequence  the 
crowns  of  the  upper  incisors 
are  forced  forwards  and  a  type 
of  superior  protrasion  Ls  pro- 
duced (see  Figs.  191,  192, 193). 
In    fact    the    appearance    is 
similar    to    those    forms    of 
protrusion     associated     with 
post-normal   occlusion  of  the 
lower  molars  to  be  described 
later,  both  in  the  appearance 
of   the    front   teeth   and   in   the   conformation 
of  the  mandible ;   but  m  the  cases  now  under 
consideration   the    occlusion    of   the    molars    is 
normal,    there    is    no    faulty    antero-posterior 
relationship    of   the  two  arches,  and   there    is 
not    usually    any    lateral    contraction    of    the 
upper  arch  or  association  with  nasal  stenosis. 
The   condition   is    'primarily   close   bite   in   the 
molar  region,  and  secondarily  protrusion  in  the 
incisor  region  of  the  upper  jaw.     It  is  in  fact 
most    closely    allied    to    those    cases    already 
described  where  protrusion  is  induced  by  pre- 
mature loss  of  the  first  permanent  molars,  with 
the    important    difference    that    in    the    latter 


examples  the  development  of  bone  may  be  quite 
normal.  The  real  origin  of  the  condition  is 
obscure,  but  it  is  very  probable  that  dimmished 
masticating  fimction  and  consequent  feeble 
bony  development  is  largely  responsible.  It  is 
not  unlikely,  however,  that  predisposition  to 
the  condition  exists  in  generally  defective 
physical  development,  either  hereditary  or  the 
result  of  environment. 

Treatment. — In  all  cases  it  is  necessary  first 


1*^10.  193. — Close  bite  with  secondary  proclination  of  upper  incisors.  This  c£ise 
ilhistrates  how,  with  premature  loss  of  the  deciduous  teeth,  the  reten- 
tion of  the  second  upper  molars  is  sufficient  to  prevent  forward  movement 
of  both  upper  and  lower  permanent  molars.  The  molar  occlusion  is 
normal,  but  the  mandible  is  probably  post-normal,  and  the  lower  molars 
have  probably  moved  for^vard.      {XormaN  G.   Bennett.) 

to  raise  the  bite.  Treatment  is  somewhat 
difiicult  and  uncertain  in  its  results,  because 
teeth  that  have  been  raised  in  theii-  sockets 
artificially  are  apt  to  revert.  A  removable  or 
fixed  appliance  may  be  employed,  the  principle 
being  to  raise  the  bite  on  the  first  permanent 
molars,  to  extrude  the  lower  (or  both  lower 
and  upper)  premolars,  and  intrude  the  lower 
mcisors.  For  the  reduction  of  the  upper  in- 
cisors, inter-maxillary  and  occipital  force  should 
be  used.  Treatment  should  be  continued  until 
after  the  eruption  of  the  second  permanent 
molars,  when  the  apparatus  may  be  disused, 
and    the    first    permanent     molars     may     be 


116 


expected  to  rise  to  the  level  of  the  other  teeth, 
or  may  be  extruded  by  means  of  inter-maxillary 
force. 

A   very  rare   kind  of   close   bite   sometimes 
occurs  in  ^^•hich  the  teeth  of  both  jaws  are  in 


as  a  whole  may  be  placed  too  far  back  or 
forward  in  relation  to  the  nose  and  forehead 
and  the  rest  of  the  face.  Case  rightly  insists 
on  the  need  for  having  regard  to  those  parts 
of  the  face  whose  appearance  is  influenced  by 
the  position  of  the  teeth.  It  is 
not  sufficient  to  consider  only 
the  antero-posterior  relation- 
ship of  the  dental  arches  to 
one  another.  Treatment  based 
on  malocclusion  only  may  result 
in  pronounced  prominence  of 
the  teeth  or  the  reverse  (usually 
the  former),  and  the  appear- 
ance of  the  patient  be  less 
pleasing  than  if  the  case  had 
lieen  left  alone  altogether.  This 
([uestion  \vill  be  considered  in 
more  detail  in  connection  with 
the  different  varieties  of  antero- 
posterior malocclusion ;  but  in 
each  variety  the  same  kind  of 
problem  often  presents  itself, 
namely,  ^^•hether  to  restore 
normal  occlusion  without  refer- 
ence to  otlier  considerations, 
or  whether  to  sacrifice  normal 

Fig.   194. — Close  bite  with  normal  occlusion,  apparently   due   to  deficient  occlusion    in    favour    of     facial 

vertical  growth  (see  Figs.  90,  91).     Right-ha,nd  figiire  shows  bite  raised  ijarmony  and  an  occlusion  that, 

in  course  of  treatment  successiuUy  accomplished  by  Case.     JNote  the  .,  u         t-  ^     '     ( 

effect  on  the  facial  contours.     {C.  S.  CA>iE  :  Dental  Orthopedia.)  tllOUgU   not   normal,  _LS   irom   a 

practical  point  of  view  suinci- 


correct  alignment  and  occlusion,  but  in  whicli 
the  degree  of  closure  is  excessive,  so  that  the 
appearance  of  the  cheeks  and  lips  has  some 
resemblance  to  that  of  an  edentulous  patient. 
An  excellent  example  of  this  is  de- 
scribed and  figured  by  Case  (43,  p.  322 ; 
see  Fig.  194).  Treatment  should  be 
on  similar  lines,  the  bite  being  tem- 
porarily raised  on  the  first  permanent 
molars,  and  the  other  teeth  being 
slowly  extruded  by  means  of  inter- 
maxillary force,  after  which  the  molars 
should  be  raised  by  the  same  means. 

2.— ANTERO-POSTERIOR 

Li  the  cases  now  to  be  considered 
either  arch  may  be  in  abnormal 
relationship  with  the  other,  that  is 
to  say,  the  upper  may  be  too  far 
back  or  forward  m  relation  to  the 
lo^^•er,  or  the  lower  may  be  too  far 
back  or  forward  in  relation  to  the 
upper.  Furthermore,  either  arch, 
whether  in  normal  relationship  with  the  other 
or  not,  may  be  too  far  forward  or  back  in 
relation  to  the  facial  contour — the  upper  or 
lower  lip  may  be  pushed  forward  or  allowed  to 
fall  too  far  back  by  variations  in  the  positions 
of  the  anterior  upper  teeth;   or  the  mandible 


ently  perfect.  In  coming  to  a  decision  between 
these  two  issues  the  question  of  the  complexity 
of  the  procedure  and  the  likelihood  of  perman- 
ence merits  much  consideration. 


A.  Upper  Apical  Zone 

B.  Upper  Coronal  Zone 

C.  Lower  Coronal  Zone 

D.  Lower  Apical  Zone 


Fig.  195. — (C.  S.  Case  :  Dental  Orthopedia.) 

The  part  of  the  face  that  is  involved  in 
deformities  of  the  jaws  and  teeth  includes  the 
alae  and  tip  of  the  nose,  the  upper  and  lower 
lips,  and  the  dim,  but  from  the  point  of  view  of 
artificial  modification  some  distinction  must 
be  drawn  between  these  several  parts.     It  is 


117 


clear  that  the  position  of  the  chin  in  relation 
to  the  nose  and  upper  part  of  the  face  is  less 
susceptible  of  alteration  than  the  lips.  Such 
a  change  can  only  be  effected  in  the  compara- 
tively rare  instances  of  successful  back^\ard 
movement  by  occipital  force,  and  for\\ard 
movement  by  inter-maxillary  force ;  these 
methods  Mill  be  dLscussed  in  connection  Avith 
the  examples  to  which  they  may  be  applicable. 
Case  (43,  p.  176)  defines  the  "  dento-facial 
area  ",  which  it  is  possible  to  modify  by  move- 
ment of  teeth,  as  being  "  formed  by  the  upper 
and  lo^^■er  lips,  and  lower  ijortion  of  the  nose, 
bounded  laterally  by  the  nasolabial  folds  and 

It  is  undeniably  true  that 
form    one    of     the    chief 

and  the  most  expressive 
and  that  the  position  of 
the  subjacent  teeth  and  bone  affects  to  a  con- 
siderable degree  the  contour  of  the  lips  in  repose 
and  the  potentiality  of  expression  of  the  lips 
in  movement.  It  is  remarkable  to  what  extent 
the  facial  harmony  and  beauty  of  the  individual 
may  be  modified  by  a  comparatively  slight 
movement  of  the  croons  or  roots  of  the  anterior 
teeth.     Case    (43,    p.    177)    shows    clearly    the 


below  by  the  chui  " 
the  mouth  and  lips 
features  of  the  face 
of  transient  emotion ; 


Fig.  196. — Normal  type,  showing  points  of  measure- 
ment (in  tlie  same  plane).  Mandibular  angle,  115°; 
profile  angle,  75°.  Note  that  the  facial  line  is 
almost  parallel  with  the  ramus.  Contrast  this 
with  Figs.  198,  199,  and  200,  in  which  the  corre- 
sponding lines  converge  in  descent.  (W.  Rushton  : 
Trans.  B.S.S.O.  ;  Dental  Record.) 

parts  affected  by  different  kinds  of  movement 
by  dividing  the  dento-facial  area  into  four 
zones,  the  upper  apical  and  coronal,  and  the 
lower  coronal  and  apical,  the  two  former  being 
modifiable    by    movement    of    the    roots    and 


crowns  of  the  u]iper  teeth  respectively,  and 
the  two  latter  by  similar  movements  of  the  lower 
teeth  (see  Fig."l!l.5).  Careful  observation  and 
judgement  are  re(juu-ed  in  determining  the  ex- 
tent to   which  an   unperfect   facial   contour  is 


Fig.  197. — Boy  just  under  ten.  Normal  type.  Tonsils 
removed  at  the  age  of  six.  (W.  Rushton  :  Trans. 
B.S.S.O.  :  D'-nlal  Record.) 

dependent  on  dental  malf)osition  ;  and  in  con- 
sidering the  possibility  of  modifying  it  beneficially 
by  tooth  movement,  or  on  the  other  hand,  the 
risk  of  magnifying  the  imperfection  by  a  method 
of  treatment  based  only  on  considerations  of 
occlusion.  The  matter  «ill  be  dealt  with 
further  under  "  Diagnosis  ". 

This  question  of  the  extent  to  which  de- 
formities of  the  mandible  are  associated  ^^ith 
errors  of  occlusion  has  been  carefuUy  investi- 
gated by  W.  Rushton  (139),  who  has  made  a 
large  number  of  measurements  of  skulls  and 
living  subjects — adults  and  children.  He 
writes  :  "  I  had  been  struck  by  ob.serving  that 
the  angle  formed  by  the  ascending  ramus  with 
the  body  of  the  mandible  varied  in  different 
people.  It  is  an  equally  true  observation  that 
the  chief  feature  of  facial  abnormality  is  caused 
by  the  position  of  the  mandible  being  anterior 
or  posterior  to  its  proper  position.  My  object 
was  to  try  and  estimate  and  correlate  these  two 
j)henomena.  To  estimate  the  former  I  took 
a  point  just  in  front  of  the  antihelix  of  the  ear 
(corresjjonding  with  the  mandibular  fossa),  the 
point  where  the  ramus  joins  the  mandible  and 
a  point  in  the  same  plane  corresponding  to  the 
point  of  the  chin.  This  is  called  the  mandibular 
angle.      To   estimate    the    latter   I   chose    the 


118 


same  point  in  front  of  the  ear,  a  point  in 
the  same  plane  corresponding  to  the  base  of  the 
nose  (these  being  probably  fairly  stable  cranial 
points),  and  measured  the  angle  formed  by 
these  with  a  line  drawn  from  the  base  of  the 


be  noted  particularly  that  according  to  his 
investigations  protrusion  of  the  mandible,  as 
judged  by  the  mandibular  and  profile  angles, 
sometimes  exists  without  labial  occlusion  of 
the  mandibular  incisors.  He  believes  that 
mouth-breathmg  is  by  far  the  most  frequent 
cause  of  these  deformities  (see  Figs.  198,  199, 
200). 

Rushton's  measurements  are — 


Normal. 

Length  Length    Total  length      Length 

of          of                 of                    of 
ramus,  body.        mandible.         face. 

Mandi- 
bular 
angle. 

Pro- 
file 
angle 

Children 
Adults   . 

11         3i       4J  (130:100) 
2J         3|       5|  (126:100) 

Retruded  Mandible. 

3i 

12r 
120° 

74° 
73° 

Children 
Adults  . 

If         2J       4i  (120:100) 
2\        3        54(107:100) 

Protruded  Mandible 

3i 

4| 

129° 
134° 

66° 
65° 

Children 
Adults  . 

lYi      3,V,     5  (119-5:100) 
2,V      3^     51(110:100) 

4A 

132° 
137° 

74° 
76° 

He  remarks  in  comiection  with  them  :  "  The 
chief  points  to  be  noted  in  the  above  tables  are 


Fig.  198. — Youth  aged  17.  Had  adenoids  and  tonsils 
removed  a  year  ago,  but  still  a  mouth- breather. 
Long  narrow  face;  large  mandibular  angle,  128°; 
small  profile  angle,  63°.  Observe  the  downward 
and  backward  drag  of  the  muscles  shown  by 
depressed  alae  of  the  nose,  short  upper  hp,  and 
retracted  mandible ;  general  aspect  of  the  face 
convex.  Upper  incisors  crowded  but  not  pro- 
truding. Narrow  arches.  The  facial  Une  and 
ramus  are  shown  to  converge  slightly  as  they 
descend.  (W.  Rushton  :  Trans.  B.S.S.O.;  Dental 
Record.) 

nose  to  the  most  prominent  point  of  the  chin. 
This  I  called  the  auriculo-facial  or  profile 
angle."  Rushton  found  that  the  mandibular 
and  profile  angles  both  for  European  skulls 
and  Greek  and  Roman  statuary  were  about 
115°  and  73°  respectively,  and  that  the  mandi- 
bular angle  is  a  very  constant  one  for  people 
of  all  races — even  the  Negro,  in  whom  the 
prognathous  appearance  is  due  not  to  obtuse- 
ness  of  the  mandibular  angle,  but  to  "  the 
profile  angle  being  large,  owing  to  the  length 
of  the  body  of  the  mandible,  the  large  teeth 
set  forward  in  the  jaws,  the  forward  inclination 
of  the  incisor,  the  thick  lips  and  flat  nose  "  (see 
Figs.  196,  197). 

Rushton  found  further  that  in  cases  of  both 
inferior  retrusion  and  inferior  protrusion  the 
mandibular  angle  was  always  more  obtuse  than 
normal ;  and  that  the  profile  angle  was  larger 
or  smaller  according  to  the  position  of  the 
mandible,  whether  normal,  protruded,  or  re- 
truded; and  also  that  protrusion  was  a  more 
common  abnormality  than  retrusion.     It  should 


Fig.  199. — Youth  aged  19.  Mouth- breather  and  has 
large  tonsils.  Long  narrow  face  (100:  100); 
mandibular  angle  large,  128°,  but  profile  angle  good 
and  facial  contour  not  unpleasing.  Both  arches 
narrow ;  teeth  crowded ;  cross  bite.  Note  everted 
lower  lip,  wliich  belongs  to  the  protruded  and  not 
to  the  retracted  mandible ;  upper  lip  not  short 
nor  alae  nasi  depressed.  (W.  Rushton:  Trans. 
B.S.S.O.;  Dental  Record.) 

tliat  in  those  cases  chosen  as  approaching  the 
normal  the  total  length  of  the  mandible  is 
considerably  greater  than  the  length  of  the 
face ;   in  the  t\\'o   other  classes   the   mandible 


119 


is  proportionately  shorter  and  the  face  longer. 
In  the  normal  the  proportions  between  the 
children's  and  adults'  measurements  remain 
very  stable ;  in  the  abnormal  classes  the  ab- 
normality is  worse  in  the  adult  than  in  the  child, 
that  is  to  say,  the  angle  has  stUl  further  in- 
creased and  the  face  lengthened." 

The  writer  has  quoted  rather  fully  from 
Rushton's  paper  because  he  considers  that  the 
work  is  an  attempt  (as  in  the  case  of  the  pro- 
sopometer of  Sim  Wallace  and  Northcroft)  to 


Fig.  200. — Girl  aged  11.  Mouth- breather ;  has  large 
tonsils.  Maxillary  arch  narrow,  mandibular  well 
developed.  Mandibular  angle  very  large,  145° ; 
profile  angle  also  large,  76°.  Note  everted  lower 
lip ;  no  "  down  drag  ".  Converging  lines  of  ramus 
and  facial  Unes  very  marked.  Medial  occlusion 
to  the  extent  of  half  an  inch.  Facial  aspect 
concave.  (W.  Rushton  :  T'rans.  B.S.S.O.;  Dental 
Record.) 

obtain  information  as  definite  as  possible  con- 
cerning variations  in  bony  development ;  and 
that  the  method  may  be  helpful  in  clinical 
investigation  of  uidividual  cases.  Rushton 
expressly  states  that  his  measurements  are 
not  mathematically  accurate ;  but  the  errors 
probably  do  not  approach  the  considerable 
variations  shown.     The  paper  merits  study. 

In  a  later  paper  Rushton  (140)  repeats  his 
previous  conclusions,  and  also  discusses  the 
apparently  hereditary  character  of  the  Habsburg 
jaw.  He  says  :  "  I  stiU  believe  that  the  main 
factor  in  abnormalities  of  the  jaws  and  teeth 
is  slight  continuous  muscular  action  caused  by 
the  open  mouth,  the  result  of  hypertrophied 
tonsils  and  adenoids ;  that  this  hypertrophy  is 
possibly  caused  by  affections  of  the  pituitary 
or  thjTeoid,  or  botli,  and  possibly  that  softness 
of  the  bone  arising  from  these  causes  allows  it 


to  be  more  easily  acted  on  by  muscular  strain ; 
that  probably  the  condition  is  in  many  cases 
hereditary;  but  whether  primarily,  or  as  a 
result  of  mouth-breathing,  I  could  not  say." 

Theoretical  Considerations.- — Before  proceeding 
to  discuss  the  different  varieties  of  antero- 
posterior malocclusion  that  actually  occur,  it 
wiU  be  well  to  consider  what  combinations  are 
possible  by  abnormal  forward  and  backward 
positions  of  the  mandible,  i.e.  of  either  arch  in 
relation  to  the  other  and  to  the  unchangeable 
upper  part  of  the  face.  It  will  jiresently  be 
seen  that  this  theoretical  consideration  accords 
remarkably  with  clinical  observations,  and  is 
of  material  assistance  in  formulating  a  scientific 
classification  of  antero-posterior  malpositions. 

For  this  purpose  it  wUl  be  sufficient  to  deal  with 
comparatively  small  relative  malpositions  ;  even 
within  narrow  limits  the  number  of  combinations 
is  considerable,  and  the  main  object  is  to  define 
the  kind  of  deformity  rather  than  the  degree. 
The  mter-digitation  of  the  cusps  usually  causes 
the  error  of  occlusion  between  upjjcr  and  lower 
teeth  to  be  the  width  of  a  premolar.  It  is  true 
that  an  intermediate  position  occurs  m  which 
corresponding  teeth  occlude  solely  with  one 
another  instead  of  inter-digitatuig,  the  outer 
cusps  of  tlie  lower  premolars  occluding  with  the 
fissure  between  the  outer  and  inner  cusps  of 
their  fellows  in  the  maxilla,  and  the  first 
permanent  molars  occludhig  in  a  somewhat 
similar  manner ;  but  the  xtnit  of  error  may  be 
defined  as  the  width  of  a  premolar,  and  the 
test  tooth  may  be  taken  to  be  the  first  permanent 
molar,  whose  position  in  an  arch  of  uninterrupted 
curvature  (whether  narrow  or  not  ij  not  the 
point)  prescribes  the  position  of  the  other  teeth. 

The  upper  arch  may  be  too  far  forward  or 
back  in  relation  to  the  face  to  a  considerable 
extent,  and  so  may  the  lower  arch,  but  it  is 
probable  that  m  very  few  cases  does  the  error 
exceed  the  width  of  a  premolar,  or  one  unit, 
and  for  the  present  purpose  errors  of  not  more 
than  one  unit  wiU  suffice.  Agaui,  the  mandilile 
as  a  whole  may  be  forward  (and  the  cliin  very 
prominent)  or  too  far  back,  but  not  usually 
to  the  extent  of  more  than  one  unit.  Of  course 
it  must  be  remembered  that  tlie  mental  promin- 
ence itself  may  be  developed  to  a  greater  or 
less  degree,  and  judgement  is  required  to  dis- 
tinguish between  this  and  malposition  of  the 
whole  mandible.  This  is  a  practical  point,  but 
does  not  affect  a  classification  including  cases 
in  which  the  whole  mandible  is  misplaced  or 
badly  developed.  It  is  possible  that  the  posi- 
tion of  the  maxilla  as  a  whole  may  vary,  but 
at  the  present  time  no  means  exist  of  estimating 
such  variation,  and  for  practical  purpcses  it 
is  sufficient  to  consider  the  antero-posterior 
variation  of  the  maxillary  arch.  This  view  is 
supported  by  SpiUer  (143).     It  should  be  clearly 


120 


understood  that  to  restrict  the  consideration 
of  displacements  to  those  of  one  unit  in  each 
variable — mandible,  upper  arch,  and  lower  arch 
■ — in  relation  to  the  unchangeable  area  of  the 
face  does  not  affect  the  theoretical  classification 
of  such  cases  (the  majority)  as  are  included ; 
those  that  are  excluded  must  be  only  variations 
in  degree  but  not  in  kind. 

It  \\ill  be  convenient  to  make  use  of  symbols 
for  the  sake  of  brevity.  Let  F  represent  the 
fixed  base  with  reference  to  which  the  three 
variables  occupy  different  positions  in  different 
cases.  It  is  not  any  definite  point,  but  repre- 
sents the  forehead,  bridge  of  the  nose,  and  malar 
bones,  as  the  most  prominent  parts  of  the 
unchangeable  upper  part  of  the  face.  Of  course 
these  various  portions  of  the  upper  part  of  the 
face  vary  in  relation  to  one  another,  but  the 
sum-total  of  these  features  forms  a  fixed  base, 
which,  for  practical  purposes,  camiot  be  modified  ; 
and  the  existence  of  individuals  with  great 
mandibular  and  maxillary  development  and 
poor  frontal  development  does  not  affect  the 
present  investigation.  Let  M  represent  the 
first  permanent  upper  molar  and  m  the  first 
permanent  lo«er  molar.  Let  C  represent  the 
mandible  as  shown  mainly  by  the  chin,  normal 
mental  development  being  assumed.  The  bear- 
ing of  abnormal  mental  development  on  the 
treatment  of  individual  cases  will  be  discussed 
later. 

Then  let  F 
M 
m 

C  represent  normal  relationship  of 

the  three  variables  to  the  fixed 

base. 

By  moving  each  of  these  variables  separately 

one  "unit  in  each  duection,  and  excluding  all 

combinations  in  which  any  two  variables   are 

separated    from    one    another    more   than    one 

unit,  the  following  combinations  are  obtained — 

A  little  consideration  will  show  that  each  of 

these  classes  exhibits  a  well-recognized  clinical 

type  of  deformity. 

Class  (a)  may' be  regarded  as  including  only 
slight  variations  from  the  normal.  The  teeth 
are  in  correct  occlusion  and  the  arches  are 
normally  disposed  ;  in  the  one  case,  the  mandible 
is  some"what  retruded,  and  in  the  other  pro- 
truded, but  the  imperfect  or  excessive  develop- 
ment has  not  been  sufficient  to  produce  a 
pre-  or  post-normal  occlusion  of  the  lower  arch. 
Class  (6)  exhibits  two  varieties  of  ^^hat  is 
correctly  described  as  Inferior  Retrusion.  This 
is  a  very  common  deformity  and  probably 
provides  the  greatest  number  of  the  cases  that 
were  formerly  all  classed  together  as  Superior 
Protrusion.  As  a  matter  of  fact  in  many  cases 
the  upper  incisors  are,  as  will  presently  be  seen, 
retruded.     In  each   variety   the   lower   molars 


(and  premolars)  are  in  post-normal  relationship 
with  the  upper,  but  in  the  one  case  the  mandible 
is  plainly  retruded,  and  in  the  other  is  about 
normally  disposed  in  relation  to  the  unchange- 
able area  of  the  face.  The  distinction  is  not 
only  a  very  real  one  clinically,  but  affords 
indications  for  different  lines  of  treatment. 


(a) 

Sub-normal. 

C 

P 

M 
m 

m 

M 
m 

F 

M 

C 
F 
m 

C 

M 
C 

m 
C 

{b) 

Inf.  Retrusion. 

m 
C 

M 

(c) 

Sup.  Protrusion. 

F 

m 
C 

M 

(d) 

Inf.  Protrusion. 

F 
M 

C 

m 

F 
M 

(e) 

Sup.  Retrusion. 

M 

C 

F 

m 

M 

F 

m 
C 

M 
m 
C 

(/) 

Double  Protrusion. 

F 
C 

M 
m 

1 

F 

(U) 

Double  Retrusion. 

M 
m 
C 

F 

M 
m 

F 
C 

Class  (c)  consists  of  true  Superior  Protrusion, 
in  reality  a  somewhat  rare  condition.  The 
upper  arch  is  too  far  forward  and  is  in  pre- 
normal  relationship  with  the  lower,  which  is 
normally  disposed  in  relation  to  the  face.  In 
the  one  variety  the  mandible  also  is  normal 
and  in  the  other  the  mandible  is  promment ; 
the   former   is   the  usual   condition. 

Class  (d)  exhibits  two  varieties  of  the  ordinary 
forms  of  Inferior  Protrusion,  in  which  the  upper 
arch  is  normal,  but  the  lower  arch  is  in  pre- 
normal  relationship  with  the  upper.  In  the 
one  variety  the  protrusion  is  mainly  of  the 
teeth,  the  mandible  bemg  normally  disposed, 
and  in  the  other,  the  more  common  form,  the 
mandible  shares  in  the  protrusion. 


121 


Class  (e)  exhibits  the  deformity  correctly 
termed  Superior  Retrusion.  These  cases  were 
formerly  grouped  under  the  head  of  Inferior 
Protrusion  or  "  underhung  bite  ",  but  in  reality 
they  are  fundamentally  different.  The  upper 
molars  are  in  post-normal  relationship  with 
the  lowers,  and  the  whole  upper  arch  is  as 
a  rule  plainly  too  far  back  in  relation  to  the 
face  and  upper  lip.  Any  false  relationship 
of  the  mandible  is  quite  an  unusual,  although 
possible,  complication. 

Class  (/)  exhibits  the  form  generally  known 
as  prognathism,  but  this  term  should  be  re- 
stricted to  conditions  in  which 
prominence  of  the  teeth  is  due  to 
excessive  bony  grow  th  anteriorly, 
such  as  occurs  normally  in  the 
Negro.  The  teeth  are  in  normal 
occlusion,  but  prominent  in  both 
jaws  ;  in  the  one  case  the  mandible 
shares  in  the  deformity,  while  in 
the  other  it  does  not — a  distinc- 
tion that  is  clinically  very  im- 
portant. 

Class  ((/)  exliibits  the  somewhat 
though  not  very  rare  condition  of 
Double  Retrusion,  in  which  the 
teeth  are  in  normal  occlusion,  but 
the  arches  are  plainly  retruded  in 
relation  to  the  face  and  lips.  The 
mandible  usually  seems  promin- 
ent, but  this  appearance  is  often 
connected  with  the  backward 
position  of  the  anterior  teeth, 
allowing  the  lips  to  fall  in. 

It  will  have  been  seen  that  the 
main  basis  of  classification  Is  con- 
cerned with  the  occlusion  of  the 
arches,  and  to  a  somewhat  less 
extent  with  the  relationship  of 
each  arch  to  the  face,  and  tiiat  the 
relationship  of  the  mandible  to 
the  face  provides,  clinically,  minor 
variations,  which  only  now  and 
then  assume  importance. 

It  should  be  clearly  recognized  that  insistence 
by  Angle  upon  the  importance  of  occlusion  as 
a  basis  of  classification  and  treatment  has  done 
much  to  advance  this  branch  of  the  subject ; 
it  is  not  perhaps  unnatural  that  its  very  value 
should  to  some  extent  have  overshadowed  other 
important  factors.  The  writer  believes  that 
the  method  here  propounded  of  considering  all 
possible  combinations  does  something  still 
further  to  restore  order  out  of  chaos.  Of  course 
it  will  be  understood  that  all  cases  do  not 
definitely  conform  to  a  clear-cut  type,  and  that 
combinations— for  example,  of  Classes  (b)  and 
(c),or  {d)  and  (e) — constantly  occur;  but  it  will 
be  found  that  even  the  most  bizarre  example 
of  antero-posterior  abnormality  is  but  a  modi- 


fication of  degree  and  not  of  kind,  and  nuist  of 
necessity  find  a  place  in  one  class  or  another, 
or  in  more  than  one.  A  classification  of  cases 
of  antero-posterior  malocclusion  somewhat  simi- 
lar to  that  herein  adopted  has  been  eminciated 
by  Sim  Wallace  (165). 

It  will  now  be  necessary  to  consider  each  of 
these  classes  in  detail. 

Class  (a),  Normal  or  Sub-normal. — Cases  in 
this  group  do  not  usually  come  withhi  the 
scope  of  treatment.  They  are  normal  in  all 
respects,  save  the  prominence  and  development 
of  the  mandible,  but  where  the  occlusion  is  not 


Fiu.  201. — lul'orior  rotrusiou  (lialf  a  unit  on  loft  siilo),  and  procliiiation 
of  upper  central  incisors,  associated  with  very  abnormal  jaw  forma- 
tion and  dental  hypoplasia.  Retained  deciduous  canines.  Not« 
the  lingual  inclination  of  lower  premolars  and  complete  lingual 
occlusion  of  those  teetli  on  the  left  side.     (Norman  ti.  Bennett.) 

affected  the  defective  or  excessive  development 
can  be  but  slight,  and  mechanical  interference 
is  neither  requisite  nor  desirable. 

Class  (b).  Inferior  Retrusion. — The  essential 
features  of  cases  of  this  group  are  that  the 
antero-posterior  relationship  of  the  upper  arch 
to  the  upper  part  of  the  face  is  normal  and  that 
the  lower  arch  is  in  post -normal  occlusion  with 
the  upper  arch.  In  the  one  type  the  mandible 
and  lower  teeth  arc  both  too  far  back ;  and  in 
the  other  only  the  teeth,  the  mandible  appearing 
to  be  in  normal  relationship  with  the  face,  and 
the  chin  not  markedly  receding,,  as  it  is  in  the 
first  type,  which  is  by  far  the  more  common. 
Clinically  the  differences  between  the  two  types 
are  of  varj-ing  degrees;  it  is' but  rarely  that  the 


122 


mandible  does  not  participate  to  some  extent 

in  the  posterior  position  of  the  teeth,  but  the 

measure  of  the  recession  presents  much  diversity. 

The  position  of   the   upper   incisor   teeth  is 


Fig.  202. — Typical  oaso  of  inferuir  retrusiun  (one  unit),  and  .sucundary  pruclina- 
tion  of  upper  incisors.      (J.  H.  Badcock.) 

nearly  always  abnormal  and 
is  of  two  distinct  types.  In 
the  more  common  form  the 
crowns  are  markedly  jyro- 
tr tided  (procliaation) ;  the 
lower  incisors  occkide  with 
the  gum  just  behind  the 
cingula  of  the  upper,  and 
are  often  arranged  in  a  fan- 
shaped  manner ;  and  the 
lower  lip  intervenes  between 
the  lower  teeth  and  the 
edges  of  the  upper  (see  Figs. 
201,  202,  203).  This  protru- 
sion is,  however,  a  secondary 
characteristic,  and  in  most 
instances  probably  a  second- 
ary development.  Cases 
must  not  be  confused  with 
those  due  solely  to  closeness 
of  bite  (antero-posterior 
occlusal  relationship  being 
normal),  or  to  thumb-suck- 
ing ;  or  ^^  itli  the  cases  of 
true  superior  protrusion 
(with  lower  teeth  and  jaw- 
normal)  shortly  to  be  con- 
sidered. In  tlie  less  common 
form  the  crowns  of  the  upper 
incisor  teeth  are  relruded 
(retroclination) ,  especially 
the  centrals,  the  laterals 
often  slightly  overlappmg 
the  centrals  on  the  labial 
aspect  (see  Figs.  204,  205). 
Angle  has  emphasized  in  the  two  divisions  of  his 
Class  II  the  essential  connection  between  these 
two  apparently  dissimilar  forms  dependent  on  a 
post-normal  position  of  the  lower  teeth. 


The  contour  of  the  arches  is  not  necessarily 
abnormal,  but  many  cases  exhibit  a  narrowing 
of  the  upper  arch  associated  usually  with  nasal 
stenosis  (see  Fig.  206) ;  and  in  some  the  arch  is 
laterally  contracted  in  the 
canine  regions,  and  the 
incisors  are  rotated  so  as 
to  exhibit  a  V-shaped  for- 
mation of  the  kind  already 
described  (see  Fig.  207).  But 
this  formation,  although  an 
expression  of  defective  bony 
development,  or  contraction 
of  the  anterior  portion  of 
the  arch,  is  far  from  being  a 
characteristic  of  thLs  type 
of  so-called  superior  protru- 
sion, of  which  the  essential 
feature  is  the  post-normal 
relationship  of  the  first  lower 
molars  and  the  premolars, 
the  proclination  and  spread- 


Fio.  2U3. — Inferior  retrusion  (lialf  a  unit),  and  secondary  proclination  of  upper 
incisors,  less  marked  than  in  Fig.  202.  The  narrow  upper  arch  is  probably 
responsible.      (H.\r<)ld  Chapman.) 

ing  of  the  upper  incisors  being  secondary  (see 
Figs.  208,  209,  210).  The  form  of  the  mandible 
is  often  far  removed  from  the  normal,  the  angle 
being  unduly  oblique  and  feebly  developed,  and 


123 


the  ascending  ramus  apparently  short.  There 
is,  in  fact,  paradoxical  as  it  seems,  a  certain 
resemblance  in  general  conformation  to  that 
seen  in  cases  of  "  open  bite  ",  but  the  horizontal 
ramus  is  usually  of  more  slender  development, 
and  the  depth  from  the  crown  of  the  first  molar 
to  the  lower  border  of  the  jaw  less  than  normal. 
There  is  also  not  infrequently  some  degree  of 
closeness  of  bite,  which,  as  has  already  been 
shown,  is  itself  a  cause  of  secondary  superior 
proclination  (see  Figs.  211  and  212).  Associated 
with  these  abnormalities  in  form,  and  perhaps 
dependent  on  them,  will  usually  be  found  some 
variation  from  the  normal  curve  of  occlusion. 
The  defect  usually  consists  mainly  in  an  elonga- 
tion of  the  lower  incisors,  but  this  is  often 
accompanied  by  want  of  depth  in  the  molar 
region. 

The  causation  of  these  forms  has  been,  and 
is  still,  the  subject  of  much  discussion,  and 
remains  debatable.  There  can  be  little  doubt 
that  the  condition  itself,  or  at  any  rate  pre- 
disposition to  it,  is  often  inherited,  as  indeed 


cases  undoubtedly  occur  in  children  who  are 
of   somewhat    feeble   physique,  and    by    whom 


b  IG.  204. — Typical  case  of  inferior  retrusion,  and  secondary  retrocliiiation 
of  upper  central  incisors.  The  occlusion  of  tlio  molars  is  normal,  but 
this  is  caused  by  loss  or  non-eruption  of  the  second  tower  premolars 
and  forward  movement  of  lower  molars.  The  whole  mandible  is  post- 
normal  (retrognatliism).     (Norman  G.  Bennett.) 

IS  the  case  in  most  gross  abnormalities  involving 
the  jaws  themselves.  This  view  is  endorsed  by 
J.  H.  Badcock  (12).     On  the  other  hand,  most 


Fio.  2().">.  — inferior  retrusion  (one  unit),  and  secondary 
retrochnation  of  upper  central  incisors,  less  marked 
than  in  case  shown  in  Fig.  204.  (Harold  Chapman.) 

mastication  has  been  imperfectly  performed. 
Unfortunately  it  is  just  these  delicate  children 
who  are  often  improperly  fed  on 
a  soft  dietary,  and  in  whom 
development  of  the  tongue  and 
jaws  is  the  more  inhibited.  The 
importance  of  malnutrition  in  the 
production  of  this  type  of  abnor- 
mality is  emphasized  by  Rodri- 
gues  Ottolengui.  It  is  probable 
that  the  condition  really  com- 
mences to  develop  during  the 
period  of  the  deciduous  dentition 
or  bef(^re ;  and  as  the  first  per- 
manent lower  molars  are  normally 
moved  forward  durmg  eruption  in 
a  well-developed  and  developing 
jaw,  it  is  not  very  difficult  to 
understand  tliat  when  growth  is 
defective  the  erupting  teeth  wiU 
remain  too  far  back  and  come  into 
post-normal  occlusion  %\itli  tlie 
upper  molars,  and  thus  remain 
locked.  If  it  were  possible  to 
trace  cases  back  to  early  years,  it 
would  almost  certainly  be  found 
that  many  of  them  followed  of 
necessity  a  post -normal  occlusion 
of  the  lower  deciduous  molars, 
occurring  not  always  as  a  gradual 
development,  but  even  from  the 
period  of  eruption.  Such  cases 
are  clearly  congenital.  (See  Part 
IV  "Deciduous Dentition", p.l35.) 
Then  there  is  the  important 
factor  of  the  frequent  narrowness 
of  the  maxillary  arcli,  perhaps 
associated  with  nasal  stenosis,  or  merely  with 
defective  growth  of  the  tongue.  The  molars 
and    premolars,    when    meeting    their    fellows 


124 


dviring  eruption,  are  guided  into  position  by 
the  interaction  of  the  cusps  ;  tliis  applies  not 
only  as   regards  the   antero-posterior  relation- 


corresponding  lower  teeth  must   occlude    buc- 
cally  :  or  the  corresponding  lower  teeth  must  be 
tilted  lingually,  contracting  tlie  lower  arch  ;  or 
non-corresponding    teeth    placed 
in  a  more  forward,  and  therefore 
narro\^•er,  part  of  the  lower  arch 
must   occlude.     As   a   matter   of 
clinical      observation     the      first 
scarcely  ever  happens,  the  second 
does  occasionally,  and  the  third 
is  the  most  usual  occurrence.    It 
is  certainly  a  fact  that  a  fairly 
expanded    lower    arch    is    often 
associated    with     a     contracted 
upper  arch  in  these  cases,  and  it 
is  at  least  pos.sible  that  the  initial 
tendency    to  post-normal    occlu- 
sion ,  by  allowing  the  second  lower 
premolars  to  occlude  with  the  ujjper  molars,  also 
permits  of  an  apparently  normal-shaped  arch  in 
a  too  backward  position.     This  explanation  is 
upheld  and  ^^ell  described  by  Brady  (35). 

The   point   is    associated    with   the  practical 
question  of  the  possibility  of  altering  the  occlu- 
sion one  unit.     Some  authors  deny  the  possi- 
bility of  this  lieing  done,  or  at  any  rate  of  the 
esult  being  permanent  a.s  regards  the  position 
of  the   mandible  as  a  whole;   but,  on  the  other 
hand,  .several  practitioners  have  advanced  very 
convincing  examples   to  prove  the  possibility. 
Federspiel  (73)  believes  that  success  is  possible 
if  the  attempt  is  made  early  enough — during  the 
development  of  the  mandibular  fossa.     There 
can  be  little  doubt  that  many  of  these  cases 
exhibit  considerable  mobility  of  the  mandible 
and  even  an  alternative  bite,  and  in  the 
experience    of    the    writer    and    many 
others,  the  treatment  is  not  only  possible 
but   effective   in    quite   young  subjects 
w  hen  associated  m  ith  early  expansion  or 
other  necessary  correction  of  the  upper 
arch.     It  is  the  latter  factor  that   not 
only  frees  the  held-back  mandible,  but 
renders    normal    occlusion    the    easiest 
position  for  the  patient.    An  interesting 
example  of  successful  treatment  on  these 
lines    of   a  patient  fifteen  years   old  is 
recorded  by  J.  G.  Turner  (156). 

The  rising  of  the  lower  incisors  and 
the    spreading    of    the    upper    are    the 
natural  result  of  the  anterior  malocclu- 
sion, and  are  most  marked  when  close- 
Fici.  20(j.— Typical  c-use  of  iiifenor  retrusion  (one  uuit)  ussoeiated     „ess   of    bite    is    a    concomitant  feature, 
witli   narrow   upper   arch.     Considerable  rotation   of   upper     rr'i  i         ■.  •  c  ^.i,  ■    „•,    ,.„  ;„ 

incisors.  Proclnlation  not  very  marked  because  of  short.iess  The  malposition  of  the  upper  inClSors  IS 
and  postplacement  of  upper  incisors  in  arch  deficiently  further  intensified  by  the  action  ot 
developed.  On  the  left  side  the  lower  molars  have  moved  the  lower  lip  in  getting  between  the 
forward.  Adenoids  removed  at  about  15  years  of  age.  upper  and  lower  teeth.  Indeed,  the 
(XoRMAN  G.  Bennett.)  r  a-  i     ii  i     i 

^  '  formation    of     the    upper    and    lower 

ship,  but  also  as  regards  the  bucco-lingual.  lips  may  be  the  chief  factor  in  determining 
Now  if  the  width  of  the  upper  arch  is  unduly  |  whether  the  upper  incisors  shall  be  inclined 
narrow  one  of  three  things  must  happen;  the  |  forwards    or    liaokwards — -a    short    upper    lip 


125 


Fig. 


permits  proclination,  a 
long  upper  lip  almost  pre- 
vents it. 

Cases    of  this   class   do 
not      necessarily     involve 
pre-normal  malposition  of 
the    upper    buccal    teeth, 
such  as  will  be  considered 
in  the  next  class  ;    but  it 
should   be    clearl\'    under- 
stood   that   any    kind    of 
combination    of    the    two 
classes     may,     and    often 
does,   occur    between   the 
two     extremes     of     pro- 
nounced mandibular  retro- 
gnathism   associated   with 
slight  secondary  proclina- 
tion of  the  upper  incisors, 
on    the    one     hand,    and 
marked    superior    protru- 
sion   on  the   other    hand, 
associated  with  abnormal 
antero- posterior    relation- 
ship of  the  premolars  and 
molars,  in  which  the  upper 
arch  is  markedly  too  far 
forward  and  the  mandible 
and  lower  teeth  but  little, 
or  not  at  all,  too  far  back. 
Treatment.  —  The     first 
essential  is  to  expand  the 
upper  arch,   if  necessary, 
and    in    some    cases    the 
lower.     The  next  requirement 
is     to    correct    the    curve    of 
occlusion.     The    form    of    the 
curve    of     occlusion    and    its 
relationship  to  the  mandibular 
articulation     has     not     often 
been    .sufficiently    taken    into 
consideration.     For   this   pur- 
pose    Snow's     face-bow     and 
an  anatomical  articulator  must 
be  used;  the  models  can  then 
be    adjusted     in     the     articu- 
lator in  their  natural  position, 
as    in    prosthetic    work.     The 
application  of  these  appliances 
to  orthodontic   treatment    has 
been    referred    to    by    R.    D. 
McBride  (110)  and  is 'fully  dis- 
cussed bv  Leuman  M.  Waugh 
(167).     The  latter  writer  points 
out    that    methods    of    treat- 
ment that  ignore  the  preserva- 
tion or  production  of  a  correct 
relationship  between  the 
curve    of    occlusion    and    the 
mandibular     articulation     are 
liable  to  permit   of  reversion. 


207. — Inferior  retrusion  (one  unit),  and  secondary  jjrotilination  of  upjier 
incisors.  Rotation  of  upper  incisors  and  postplacement  due  to  deficient 
anterior  development.  The  upper  arch  is  very  narrow,  and  tlie  upper  molars 
are  all  in  lingual  occlusion.  This  narrowness  is  probably  responsible  for 
the  post-normal  position  of  the  mandible  (retrognathism),  which  is  otherwise 
well  developed.     (.J.  H.  Badcock.) 


Fig.  208. — Inferior  retrusion  (half  a  unit),  and  secondary  proclination  of 
upper  incisors,  associated  with  wide  arches.    (Norman  G.  Bennett.) 


126 


However,    information  appears  to  be  wanting 
with  regard  to  normal  conditions   at   different 


Fig.  209. — Inferior  retrusion,  and  secondary  proclina- 
tion  of  upper  incisors,  associated  with  fairly  wide 
upper  arch.  Tlie  main  defect  here  is  in  tlie  small 
size  of  the  mandible.  The  first  lower  molars  have 
been  able  to  move  forward  into  normal  occlusion 
•with  the  upper  molars  owing  to  premature  loss  of 
the  second  lower  deciduous  molars.  (J.  E.  Spiller.) 


distinguish  between  a  forward  movement  of  the 
whole  mandible  (associated  presumably  with 
modifications  of  the  condyle), 
and  forward  translation  of  all 
the  lower  teeth.  The  former 
only  may  correctly  be  described 
by  this  term,  and  according  to 
many  operators  can  be  success- 
fully accomplished.  A  case  in 
point  is  recorded  by  Ottolengui 
(126).  In  a  useful  paper  by  S. 
Merrill  Weeks  (168),  bearing 
upon  this  problem,  the  relation- 
ship between  the  formation  of 
the  mandibular  articulation  and 
abnormal  occlusion  and  jaw  for- 
mation is  discussed.  Weeks  con- 
siders that  the  variation  of  facial  contour  in  the 
class  of  cases  under  consideration,  and  in  others, 
can  only  be  accounted  for  by  a  false  relation 
of  the  mandible  as  a  whole,  and  that  movement 
of  teeth  alone  cannot  produce  correction.  Mat- 
thew Cryer  gives  illustrations  of  a  large  number 
of  specimens,  in  opening  a  discussion  on  Weeks's 
paper.  R.  D.  McBride  (110)  discusses  very  fully 
the  physiological  changes  involved  in  "  jumping 
the  bite ".  He  considers  that  no  permanent 
change  takes  place  when  a  bite-plate  with 
inclined  plate  behind  the  upper  incisors  Is  used, 
because  although  the  habit  may  be  acquired  of 
biting  hi  normal  occlusion  the  mandible  drops 
back  in  a  position  of  rest.  Before  the  intro- 
duction of  inter-maxillary  force  he  used  bite- 
bars  attached  to  molar  crowns  in  association 
with  a  bite-plate,  so  that  a  post-normal  position 
of  the  mandible  was  at  all  times  impossible  to 


ages,  and  until  this 
has  been  obtained 
any  estimate  of  the 
degree  of  abnormality 
in  particular  cases  is 
impossible.  Thec|ues- 
tion  of  the  correction 
of  the  occlusion  de- 
pends upon  the  extent 
to  which  the  mandible 
as  a  whole  shares  in 
the  post-normal  re- 
lationship of  the  lower 
teeth.  Where  this  is 
marked  an  attempt 
should  be  made,  in 
young  subjects  at 
least,  to  bring  forward 
the  mandible  ;  it  will 
probably  be  necessary 
also  to  raise  the  bite 
and  depress  the  lower 
incisors.  Case  considers  that 
to    "jump  the  bite",   and   it 


,  210. — Portraits  of  case  shown  in  Fig.  209  before  and  after  treatment. 

it  is  impossible   1   the  patient,  and  in  this  way  considered  that  he 
is    necessary  to   |   obtained  permanent  results  by  causing  modifica- 


127 


tions  of  the  eminentia  articularis,  and  the 
formation  of  a  new  site  of  articulation.  In  a 
later  paper  McBride  (111)  shows  some  excellent 
results  achieved  by  the  use  of  inter-maxillary 
force,  and  in  recent  years  many  other  operators 
have  published  similar  cases.  It  should  be 
stated,  however,  that  some  operators  do  not 
believe  in  the  permanency 
of  the  result.  They  con- 
sider that  although  the 
teeth  remain  in  normal 
occlusion  the  mandible 
drops  back  to  its  old  posi- 
tion, i.e.  the  teeth  move 
forward  in  the  bone.  If 
treatment  so  far  has  been 
successful,  the  correction  of 
protruded  upper  incisor 
crowns  will  then  be  the 
least  difficult  part  of  the 
process  and  can  be  accom- 
plished by  occipital  force, 
or  traction  from  within  the 
mouth.  In  cases  of  retro- 
clination  of  the  upper 
incisors  the  position  of  the 
crowns  will  have  been 
partially  corrected  during 
expansion,  before  altera- 
tion of  occlusion,  and  can 
be  completed  afterwards. 

\\'lien  it  is  impossible, 
or  unwise  to  attempt,  to 
change  the  occlusion  and 
advance  the  mandible,  the 
lower  buccal  teeth  should 
not  be  disturbed.  If  they 
are  moved  forward,  even 
though  it  be  into  what  is 
really  a  normal  position 
and  normal  occlusion,  the 
effect  will  be  to  produce  the 
appearance  of  a  markedly 
receding  chin.  The  better 
treatment  of  cases  char 
acterized  liy  procluiation 
of  the  upper  incisors  is  to 
raise  the  bite  and  depress 
the  lower  incisors,  and  to 
extract  the  first  upper  pre- 
molars and  draw  back  the 
upper  incisors.     This  plan, 

however,  is  usually  inadvisaljle  in  cases  of  retro- 
clination  of  the  incisors,  for  it  is  difficult  to 
move  back  the  roots  sufficiently  to  close  the 
space  formed  by  extraction  and  produce  good 
alignment  of  the  incisors. 

Those  cases  in  which  the  post-normal  relation- 
ship is  limited  to  the  lower  teeth  require  a 
different  plan  of  treatment.  Advancement  of 
the  mandible  is  clearly  out  of  the  question,  and 


extraction  of  the  first  upper  premolars  would 
produce  a  laxity  and  depression  of  both  lips, 
and  an  appearance  somewhat  resembling  that 
of  edentulous  old  age.  The  proper  treatment 
is  to  dra«-  forward  the  lower  teeth  by  means  of 
inter-maxillary  force,  to  treat  the  closeness  of 
bite    when    necessary,    and    correct    the    upper 


Fi(i.  211. — Extreme  case  of  interior  retru.siori,  and  secondary  proclinatioii  of 
upper  incisors,  combined  with  closeness  of  bite.  There  is  no  occlusion  of 
posterior  teeth ;  and  premature  loss  of  the  deciduous  teeth  associated  with  the 
post-normal  position  of  tlie  mandible  has  allowed  the  lower  incisors  to  tilt 
the  upper  incisors  forward.     (Xorman  G.  BENNErr.) 

incisors.  This,  of  course,  involves  a  somewhat 
extensive  movement  of  teeth,  but  will  probably 
produce  the  best  result  if  carried  out  slowly. 

In  estimating  the  relative  positions  of  the 
mandible  and  arches  the  methods  of  measure- 
ment suggested  by  Rushton  (see  pp.  118  and 
119)  should  be  found  very  useful.  The  same 
observation  applies  to  the  other  classes  in  this 
group  presently  to  be  discussed. 


128 


In  all  these  cases  retention  is  necessary  for 
a  considerable  period  after  treatment — at  least 
a  year  and  often  more, — and  permanency  of 
result  will  depend  upon  the  extent  to  which 
later  bony  development  compensates  for  early 


Fig 


212. — Portrait  of  case  shown  in  Fig.  211. 
the  well-marked  inferior  retrognathism. 


Note 


defect.  Treatment  to  be  successful  must  take 
into  accoiuit  physical  characteristics,  and  oper- 
ate in  conjunction  with  natural  gro\rth  and  not 
in  opposition  to  it.  The  question  of  general 
treatment  liaving  reference  to  functions  of  the 
jaws  and  tongue  is  dealt 
with  in  another  section. 

Class  (c),  Superior  Protru- 
sion. —  In  this  class  the 
lo\^er  teeth  are  in  correct 
relationsliip  \\  ith  the  upper 
part  of  the  face,  but  the 
upper  teeth  are  in  pre- 
normal  occlusion  with  the 
lower,  that  is  to  say,  the 
whole  upper  arch  is  too  far 
forward,  ^'ariations  occur 
in  the  relationship  of  the 
mandible  to  the  face,  but 
do  not  usually  exceed  the 
range  that  may  be  con- 
sidered to  be  embraced 
within  normal  limits.  Pro- 
minence of  the  upper  in- 
cisors and  upper  lip  will 
often  cause  the  chin  to 
appear  recessive  when  such 
is  not  really  the  case.  In  estimating  the  abnor- 
mality of  the  parts  of  the  facial  profile  below 
the  nose  each  portion  should  be  considered  in 
relation  to  the  unchangeable  area  of  the  upper 
part  of  the  face. 


The  protrusion  of  the  upper  incisors  conse- 
quent on  pre-normal  occlusion  of  the  upper 
molars  and  premolars  to  the  extent  of  one  unit 
may  take  various  forms,  and  exhibit  minor 
modifications  of  true  superior  protrusion.  The 
usual  form  is  that  in  which  the  crow  ns  alone  are 
protruded  and  spread  (proclination),  the  apices 
of  the  roots  being  normally  situated.  In  other 
cases  the  roots  also  are  unduly  prominent  (pre- 
placement).  In  rare  examples  this  prominence 
of  the  roots  is  excessive,  so  that  the  cro\\iis, 
although  really  too  far  forward,  do  not  appear 
to  be  protruded.  On  the  other  hand,  in  cases 
of  marked  protrusion  of  the  crowns  the  apices 
of  the  roots  may  even  be  somewhat  re  traded. 
To  what  extent  excessive  bony  growth  (pro- 
gnathism) is  concerned  m  these  types  of 
deformity  is  uncertain. 

The  cause  of  true  superior  protrusion  is  un- 
known. It  is  difficult  to  see  how  errors  in 
development  due  to  conditions  of  environment 
and  function  can  bring  it  about,  unless  it  be 
supposed  that  such  cases  are  in  the  first  place 
post-normal  occlusion  of  the  lower  teeth,  and 
that  subsequent  growth  has  compensated  for 
the  early  deficiency  and  carried  forward  the  teeth 
of  both  jaws.  It  is  probable  that  congenital 
variation  is  responsible  for  most  of  these  cases. 
It  should  be  remembered,  however,  that  the 
type  is  a  comparatively  rare  one,  and  that  most 
cases  of  superior  protrusion  are  associated  with 
some  degree  of  inferior  retrusion.'  It  has  already 
been  pointed  out  tliat  between  the  two  extremes 
of  classes  (6)  and   (c),  considered  .separately  for 


Fig.  213.- 


Inferior  protrusion.      Edge  to  edge  bite, 
in  pre-normal  occhision  (half  a  unit). 


lower  molars  and  premolars 

(G.    NORTHCKOFT.) 


the  sake  of  lucidity,  an  infinite  variety  of  com- 
binations may,  and  does,  occur. 

•  As  has  already  been  stated  (p.  81),  J.  F.  Colyer 
ascribes  many  cases  of  both  classes  to  the  use  of  the 
"baby  comforter." 


129 


Rodrigues  Ottolengui  (125)  appears  to  deny 
the  existence  of  this  class  of  eases,  for  in  dis- 
cussing abnormal  antero-posterior  occlusion, 
he  states  that  where  the  relationship  is  such 
that  tlie  anterior  two-thirds  of  the  lower  molar 
occludes  with  the  posterior  two-thu-ds  of  the 
upper  molar,  the  fault  always  lies  with  the  lower 
molar,  or  mandible  as  a  \\  hole.  That  Ls  to  say, 
the  lower  molar  is  in  post-normal  occlusion, 
not  tlie  upper  in  pre-normal  occlusion,  and  the 
condition  is  inferior  retrusion  and  not  superior 
protrusion.  In  a  similar  way  he  argues  that  in 
the  converse  state  of  affairs  the  lower  arch  is 
always  in  pre-normal  occlusion,  and  the  upper 
never  in  post-normal  occlusion,  and  that 
inferior  protrusion,  therefore,  is  what  must  be 
dealt  with,  and  never  superior  retrusion.  N.  S. 
Hofi  in  discussing  the  paper  dissents  from  these 
views,  and  in  the  opinion  of  the  writer  clinical 
experience  shows  Ottolengui's  view  to  be 
untenable.  The  paper  is  illustrated  with  ad- 
mirable examples  of  hiferior  retrusion.  E.  H. 
Angle  (4)  also  regards  the  first  upper  molar  as 
a  tooth  whose  position  is  almost  invariable, 
except  as  regards  diversity  in  racial  type,  and  he 
appears  to  deny  the  existence  of  a  true  superior 
protrusion.  It  is  not  easy,  however,  to  draw 
a  hard-and-fast  line  between  racial  or  individual 


premature  loss  of  deciduous  molars  already 
described,  the  upper  first  molars  have  moved 
forward  to  a  very  considerable  extent.  The 
^vriter  has  knowledge  of  an  adult  in  whom  a 


B^IG. 


Note 


Fig.  214. — Inferior  protrusion  associated  with  well-formed  arches.  Lower  molars  and 
premolars  in  pre-normal  occlusion  (one  unit).  The  mandible  itself  is  too  far  forward 
(prognathism).      (B.  E.  Lischer  :  Dental  Cosinos.) 

variation,  within  normal  limits,  and  abnormal 
variation  ;  and,  furthermore,  most  practitioners 
are  familiar  with  cases  in  which,  as  a  result  of 
5 


215. — Portrait  of  case  sliown  iu  Fig.  214. 
the  well-marked  inferior  prognathism. 

first  permanent  upper  molar  is  in  contact  \\ith 
the  canine.     If  such  movement  is  possible  under 

any  conditions,  it 
seems  unwise  to 
deny  its  occurrence 
even  apart  from 
any  question  of  loss 
of  teeth  anterior  to 
the  molar. 

TrealmetU.—The 
principles  of  treat- 
ment are  in  all 
cases  the  same. 
If  the  upper  teeth 
are  too  far  forward 
extraction  is  neces- 
sary, and  the  first 
upper  premolars 
should  usually  be 
chosen.  Where  the 
first  upper  molars 
are  extensively 
carious  these 
should  be  extracted 
and  the  premolars 
moved  back.  The 
mcisors  may  be 
corrected  by  means 
of  a  movable  or 
fixed  apparatus 
within  the  mouth, 
or  by  occipital 
force,  or  by  both.  Some  \\  riters  advise  the  back- 
ward movement  of  all  the  upper  teeth,  but  it  is 
difficult  to  see  any  great  advantages  in  this  plan 


130 


of  treatment,  and  the  disadvantages  are  very 
obvious.     Cryer   (60)   gives  good  examples   to 


Fig.  216. — Superior  retrusion,  combined  with  inferior 
to  some  extent.  The  cliief  defect  lies  in  the  ■ 
developed  maxilla  (retrognatliisna)  and  upper 
arch.  The  mandible  is  not  very  much  too  far 
forward,  but  appears  so  by  contrast  with  the 
depressed  upper  lip  (see  next  figure).  The  con- 
formation of  the  mandible  is  abnormal;  note 
the  very  obtuse  angle,  the  pointed  chin,  and 
great  anterior  depth.  This  form  of  mandible 
is  not  infrequently  associated  with  this  type  of 
abnormal  occlusion.  In  closing,  the  lower  teeth 
pass  entirely  outside  the  upper  arch.  The  retro- 
clination  of  the  lower  incisors  is  caused  by  pressure 
of  the  lower  lip.     (Norman  G.  Bennett.) 

show  the  inadvisability  of  backward  movement 
of  molars  m  certain  conditions. 

Movement  of  the  roots  either  forward  or 
backward  is  possible  by  means  of  the  "  contour- 
ing apparatus  "  designed  by  Case.  Li  some 
cases  it  may  be  necessary  to  raise  the  bite,  or 
depress  the  lower  incisors,  in  order  to  reduce  the 
upper  incisor  crowns  to  a  normal  position. 

Combinations  of  Classes  (b)  and  (c).  —  Treat- 
ment ua  these  cases  will  naturally  include  the 
methods  applicable  to  each  of  the  pure  types. 
Considerable  judgement  will  be  required  to 
decide  to  what  extent  the  upper  or  lower  teeth 


contrary  movement  of  upper  and  lower  teeth 
is  usually  required,  the  treatment  is  to  some 
extent  simplified,  and  it  is  to  cases  of 
this  type  that  inter-maxillary  force  is 
particularly  applicable. 

Class  (d),  Inferior  Protrusion. — All 
cases  in  this  class  are  characterized 
by  pre-normal  occlusion  of  the  lower 
molars  and  premolars,  and  labial,  or 
edge  to  edge,  malposition  of  the  canines 
and  incisors  (see  Figs.  213,  166,  167). 
In  some  the  protrusion  Ls  limited  to 
the  teeth,  and  in  others  the  mandible 
shares  in,  or  is  even  the  most  con- 
spicuous feature  of,  the  deformity. 
Pure  examples  of  these  types  are 
perhajis  some^A'hat  rare,  the  cases 
being  complicated  by  retrusion  of  the 
upper  teeth,  but  for  the  sake  of  clear- 
ness the  latter  vvUl  be  considered  separ- 
ately. The  class  includes  examples  of 
remarkable  deformity,  and  the  exact 
cause  is  not  understood.  Obviously 
there  exists  an  over-development  of 
the  mandible  (prognathism)  in  many 
cases,  or  at  least  evidence  of  an 
irregularity  of  development  (see  Figs. 
214,  215).  In  those  cases  where  the 
teeth  are  cliiefly  at  fault  it  is  reason- 
able to  suppose  that  the  original  cause 
of  the  pre-normal  occlusion  has  been 
an  excessive  gro^vth  of  bone  about  the 
angle  of  the  mandible  at  a  compara- 
tively early  age.  On  the  other  hand, 
protrusion  '*  i®  probably  true  that  prominence  of 
rery  badly     the  mandible  itself  generally  occurs  as 


Fig.  217. — Portrait  of  case  shown  in  Fig.  216. 
the  features  there  referred  to. 


Note 


the  result  of  abnormal  development  during  the 
(and  mandible)  are  at  fault ;  but,  inasmuch  as  a  I   later  periods  of  adolescence,  and  cases  have  been 


131 


described  in  which  the  error  of  occlusion  and  the 
protrusion  of  the  mandible  commenced  con- 
temporaneously with  the  eruption  of  the  third 


Fig.  2 is. — Inferior  protrusion  (prognathism)  combined 
with  superior  retrusion  (retrognathisni).  Tlie 
lower  arch  is  well  developed,  but  not  abnormally 
large ;  the  posterior  teeth  are  all  tilted  lingually. 
The  maxilla  and  upper  arch  are  badly  developed. 
The  lower  molars  and  premolars  are  in  pre-normal 
occlusion  (one  unit)  and  also  in  buccal  occlusion. 
The  retroclination  of  the  lower  incisors  and  canines 
is  caused  by  pressure  of  the  lower  lip.  (N'orman 
G.  Bennett.) 

molars.  But  the  real  cause  of  excessive  develop- 
ment of  bone  of  one  kind  or  another  is  for  the 
present  quite  obscure.  There  is  undoubted 
evidence  of  uilierited  tendency  in  many  cases. 

Li  other  cases  habit  seems  to  play  an 
important  part  in  the  development  of  this 
deformity,  and  according  to  Henry  A.  Baker 
(17)  the  condyle  then  adopts  an  abnormally 
anterior  position ;  he  believes  that  it  is  only 
in  such  examples  that  the  deformity  may  be 
reduced  by  a  backward  movement  of  the  whole 
mandible. 

Treatment. — Whenever  it  is  thought  that  the 
deformity  is  prirnarily  one  of  habit  an  attempt 
should  be  made  to  reduce  the  mandible  with 
the  skull-  and  chin-cap.  Where  this  is  impossible, 
the  first  necessity  of  treatment  is  to  extract  the 


two  first  lower  premolars ;  the  anterior  teeth 
can  then  be  retruded  by  means  of  inter-maxillary 
force  associated  with  the  application  of  occipital 

force.     Where  the  deformity 

concerns  chiefly  the  teeth 
this  wiU  usually  effect  a 
successful  result,  but  in  cases 
where  the  mandible  is  pro- 
truded, this  prominence  will 
be  somewhat  accentuated, 
and  it  is  justifiable  to  move 
forward  the  upper  incisors 
to  some  extent  rather  than 
retrude  the  lowers  so  far  as 
would  be  necessarj'  to  cause 
them  to  occlude  lingually 
with  the  uppers.  A  move- 
ment of  the  crowTis  alone  -of 
the  lower  anterior  teeth  will 
not  as  a  rule  suffice  to  correct  the  deformity, 
and  the  "contouring  appliance"  of  Case  is 
probably  the  best  method  of  retruding  the 
roots  also.  It  must  be  agreed  that  cases  of 
this  class  are  among  the  most  difficult  to  treat 
with  permanently  good  results  ;  but  successful 
results  with  the  skull-  and  chin -cap  were  re- 
corded by  F.  Heuckeroth  (90)  (91)  as  long 
ago  as  1892.  Abnormal  development  continued, 
as  it  often  is,  until  a  late  age  defies  treat- 
ment by  mechanical  means,  and  even  in  the 
simpler  cases  retention  appliances  are  neces- 
sary for  a  prolonged  period.  The  somewhat 
severe  operation  of  double  resection  of  the 
mandible  was  probably  first  recommended  by 


Fig.  219. — Portrait  of  case  shown  in  Fig.  218.  Note 
the  depressed  upper  lip,  and  the  prominent 
mandible  with  very  obtuse  angle. 

Angle.  The  first  case  that  the  \vriter  can  find 
is  recorded  by  J.  Wiipple  (170),  and  the  opera- 
tion was  performed  by  Blair.     After  removal 


132 


of  a  piece  of  bone  on  each  side  the  bones  were 
wired.  Tlie  wires  failed  to  hold,  and  Wliipple 
continued  the  treatment  with  fracture  bands 
and  traction  screws  with  a  considerable  measure 


Fig.  220. — Double  protrusion  with  well-formed  arches  and  normal  occlusion.  The  right- 
hand  figures  show  the  result  of  treatment  by  extraction  of  four  first  premolars  and 
drawing  back  the  anterior  teeth.  (C.  L.  Goddard  ;  Trans.  Amer.  Soc.  of  Ortho- 
dontists; Items  of  Interest.) 


of  success.  Angle  (5)  considers  that  a  better 
result  ^^ould  have  been  obtained  if  a  metal  or 
vulcanite  splint,  made  to  a  corrected  model  and 
cemented  to  the  teeth,  according  to  the  method 
adopted  in  case  of  fracture,  had  been  employed, 
instead  of  wiring  the  bones.  Operations  on 
other  cases  have  been  carried  out  with  appa- 
rently satisfactory  results  by  Arbuthnot-Lane 
(ft)  in  England,  and  others  in  America  (19)  (28) 
(147)  ;  and  recently  by  H.  P.  Pickerill  (129)  in 
Xew  Zealand.  The  methods  are  fully  discussed 
by  W.  Wayne  Babcock  (10). 

Class  (e),  Superior  Retrusion. — In  this  class 
the  lower  teeth  are  in  normal  relationship  with 
the  upper  part  of  the  face.  There  is  an  appear- 
ance of  inferior  protrusion,  ■\\hich  is  really  due 
to  the  whole  upper  arch  being  placed  too  far 
back.  In  many  cases  the  upper  arch  seems  to 
be  entirely  too  small  for  the  lower  and  there  is 
not  only '  post-normal  occlusion  of  the  upper 
molars  and  premolars,  but  lingual  malocclusion 
as  well.  Variations  may  occur  in  the  position 
of  the  mandilile  in  relation  to  the  lower  teeth 
and  to  the  facial  contour,  but  in  pure  examples 
of  superior  retrusion  these  small  variations  are 


only  of  academic  mterest,  and  do  not  affect  the 
salient  features  of  the  deformity  (see  Figs.  216, 
217). 

The  cause  of  this  medial  misplacement  and 

contraction  of  the 
entue  upper  arch  is 
obscure.  In  many 
cases  it  is  clearly 
connected  with 
nasal  stenosis  and 
consequent  imper- 
fect expansion  and 
growth  of  the 
maxilla  (retrogna- 
thism),  and  in  fact 
a  condition  of  open 
bite  due  to  the 
same  cause  is  often 
combined  with  the 
other  deformity. 
Turner  (155,  p.  337) 
well  remarks  :  "If 
the  difficulty  of 
breathing,  even  of 
mouth  -  breathing, 
be  very  great  owing 
to  adenoids,  en- 
larged tonsils,  or 
enlarged  lingual 
tonsUs,  the  child 
\\ill  not  merely 
drop  the  jaw  inter- 
mittently, but  will 
constantly  hold  the 
mandible  down- 
wards and  forwards 
Thus  the  mandibular  arch 


by  muscular  action 

entirely  escapes  from  the  containing  maxillary 

arch,    and   a    maxilla    of   stimted   growth    and 


Fifi 


-INji'ti'aits  ui  cii.se  shown  in  Fig.  22l.) ; 
treatment ;  B,  after  treatment. 


tore 


compressed  by  mouth -breathing  is  opposed  by 
a  full-grown  mandible  whose  horizontal  ramus 
may  have  been  compressed  by  excessive  muscular 
action  (mylo-hyoids)  and  by  excessive  lateral 
pressure.     All    this   means   inferior   protrusion. 


133 


The  appearance  of  protrusion  is  accentuated  on 
closing  the  teeth,  as  in  edentulous  old  people." 

Case  attributes  the  evil  to  extraction  of  the 
first  permanent  molars.  No  doubt  this  is  a 
fruitful  cause  of  maxillary  contraction,  but  it 
is  difficult  to  see  how  upper  incisors  that  have 
fully  erupted  in  normal  labial  occlusion  with  the 
lower  will  be  induced  to  fall  back  as  the  result 
of  such  interference.  In  eases  of  deficient 
anterior  development  when  the  upper  incisors 
are  already  in  lingual  occlusion  with  the  lower, 
extraction  of  the  first  permanent  molars  will, 
of  course,  intensify  the  evil  and  produce  an  ex- 
tremely contracted  upper 
arch.  However,  the  only 
cases  properly  included  in 
this  class  are  those  in 
which  all  the  teeth  are 
present,  or  at  any  rate 
those  in  which  extraction 
has  been  an  incident  rather 
than  a  cause  of  evil ; 
among  such  many  ex- 
amples of  the  deformity 
under  discussion  occur. 

Treatment. —  Treatment 
is  difficult  and  unsatis- 
factory, for  the  reason 
that  no  application  of 
mechanical  force  will  com- 
pensate for  defective  bony 
growth.  For  the  sake  of 
appearance  it  is  often 
good  treatment  to  restore 
the  anterior  teeth  to 
normal  occlusion  by  mov- 
ing forward  both  cro\TOs 
and  roots,  and  to  insert 
artificial  substitutes  pos- 
teriorly. Where  the 
maxiLIarjf  deformity  is  not 
excessive  it  may  be  per- 
missible to  accept  the  evU, 
such  as  it  is  and  reduce 
the  lower  arch  m  the  way 
already  described. 

Combinations  of  Inferior 
Protrusion  and  Superior  Retrusion. — It  should  be 
clearly  understood  that  just  as  inferior  retrusion 
and  superior  protrusion  occur  commonly  in 
combination,  so  also  do  inferior  protrusion  and 
superior  retrusion  (see  Figs.  21S,  219).  The 
treatment  necessary  will  then  involve  both  arches, 
and  in  fact  may  be  the  simpler  for  that  reason, 
because  not  only  is  a  smaller  movement  of 
the  teeth  of  each  arch  required,  but  the  use 
of  inter-maxillary  force  is  the  more  applicable. 

Class  (f),  Double  Protrusion. — In  this  class  the 
relationshij)  between  the  upper  and  lower  teeth 
is  normal,  but  both  arches  arc  placed  too  far 
forward  in  relation  to  the  upper  part  of  the 


face  and  lips,  and  possibly  an  overgrowth  of 
bone  produces  a  share  in  the  deformity.  The 
condition  is  not  very  common,  but  the  pre- 
placement  or  proclination  is  very  prejudicial 
to  appearance.  The  mandible  as  a  whole 
shares  m  the  prominence  of  the  teeth  to  a  vary- 
ing extent,  but  as  a  general  rule  the  deformity 
involves  the  teeth  alone  or  chiefly.  The  align- 
ment of  the  teeth  is  generally  regular,  and  the 
prominence  of  the  upper  incisors  often  includes 
the  roots  and  superjacent  l)one  as  much  as 
the  crowns.  A  good  example  of  the  condition 
is  figured  and  described  by  C.  L.  Goddard  (78), 


Fig.  222. — Left-hand  figures  show  double  protrusion  «itli  nonual  ocehision. 
Middle  figiu-es  show  normal  molar  occlusion  and  normal  profile.  Right-hand 
figures  show  double  retrusion  (the  lower  arch  is  in  post-normal  occlusion). 
The  face  casts  are  very  good  examples  of  these  types  of  profile.  (C.  S.  Case  : 
Dental  Orthopedia.) 

who  extracted  the  four  first  premolars  as  part 
of  the  method  of  treatment  (see  Figs.  220,  221). 
In  the  discussion  on  the  pajier.  by  E.  H. 
Anglo  and  others,  rather  contradictory  views 
were  expressed.  Angle  regards  such  cases  as 
extreme  rarities,  and  as  belonging  to  a  special 
type  of  face.  He  considers  Goddard's  treat- 
ment incorrect,  and  that  widening  the  arches 
and  reduction  of  the  incisors  would  have 
produced  a  more  satisfactory  result.  Other 
speakers  considered  the  original  condition  more 
in  harmony  with  the  type  of  face  than  the 
condition  produced  by  Goddard's  treatment. 
In  the  clinical  experience  of  the  writer,  such 


134 


cases,  although  not  common,  are  not  ex- 
tremely rare,  and  in  his  opinion  the  best 
results  cannot  often  be  obtained  without  the  aid 
of  extraction.  In  a  study  of  the  question  from 
the  comparative  standpoint,  E.  C.  Kirk  (99) 
speaks  of  irregularities  of  position  of  the  dental 
arches,  even  though  the  occlusion  is  perfect. 

The  cause  of  the  condition  is  not  known. 
Beyond  the  fact  that  there  is  excessive  bony 
gro^^i:li  (prognathism),  approaching  almost  to 
the  condition  usually  characterized  as  hyper- 
trophy, little  more  can  be  said.  It  is  diiiScult 
to   connect   the   deformity   with    conditions   of 


Fig.  223. — Lingual  occlusiuu  uf  second  right  lower 
molar.  Lingual  displacement  of  lower  lateral 
incisors.     (G.  Northcroft.) 

environment,  and  although  it  is  probable  that 
the  potentiality  must  exist  as  a  genetic  varia- 
tion, there  is  not  sufficient  evidence  of  its  direct 
transmissibility  as  an  inherited  characteristic. 

Treatment. — Treatment    depends    upon    the 

extent  of  the  deformity.    As  has  just  been  said, 

in  many  cases  good  results  can  be  achieved  by 

expansion  of  the  arches  and  lingual  movement 

of  incisors.     In  others  four  first  premolars,  or 

posterior  teeth  when  extensively  carious,  must 

be  removed  prior  to  reduction  of  incisors.     It 

will  often  be  necessary  to  draw  back  the  roots 

j^i  well  as  the  crowns  of  the  upper  teeth,  but 

jjjs  form  of  treatment  is  less  efficacious,  and 

j^g  '^nately  less  often  necessary,  in  the  case  of 

of  thf^^'"  incisors  and  canines. 

and  to(S)'  Double  Retrusion. — This  is  an  unusual 

of  supp'^'  ^^^  ^^  *^'^^  opposite  of  the  last ;  the 


arches  are  in  normal  occlusion,  but  are  post-nor- 
mally placed.  The  amount  of  retrognathism  of 
the  mandible  itself  is  variable,  but  is  not  usually 
very  obvious.  In  fact  the  diminished  support 
to  the  lips,  and  the  accentuation  of  the  normal 
folds  of  the  lips,  cause  the  chin  to  appear  rela- 
tively prominent,  and  produce  an  appearance 
somewhat  similar  to  tliat  caused  by  a  close-bite 
malocclusion.  The  incisors  often  have  a  lingual 
inclination  (retroclination)  (see  Fig.  222). 

The  cause  'of  the  condition,  beyond  the  fact 
that  bony  development  is  uniformly  deficient 
(retrognathism),  is  unknown.^ 

Treatment. — Treatment  at 
the  best  is  unsatisfactory; 
any  general  movement  of  all 
the  teeth  is  out  of  the  ques- 
tion. The  lingual  inclination 
may  be  corrected  with  bene- 
ficial results,  but  otherwise 
cases  of  only  moderate  de- 
formity are  best  left  alone. 
It  is  sometimes  recommended 
to  advance  the  anterior  teeth 
and  supply  artificial  substi- 
tutes for  the  spaces  thereby 
created,  but  the  wisdom  of 
this  course  is  doubtful. 

3.— LATERAL. 

Reference  has  already  been  made  to  the  fact 
that  in  cases  of  ill-developed  upper  arches  the 
upper  buccal  teeth  occlude  with  the  lower  in  such 
a  way  that  the  outer  cusps  of  the  upper  are  lingual 
to  the  outer  cusps  of  the  lower.  A  remarkable 
example  of  the  reverse  condition  in  which  the 
lower  teeth  are  completely  lingual  to  the  upper, 
and  in  fact  do  not  occlude  at  all,  is  described  by 
J.  H.  Badcock  (13).  Lateral  malocclusion  of  a 
single  upper  or  lower  premolar  or  molar  is  not 
at  all  uncommon  (see  Figs.  223,  201,  207). 

A  condition  in  which  on  one  side  the  occlusion 
is  apparently  normal,  and  on  the  other  the  upper 
teeth  are  in  lingual  malocclusion,  sometimes 
occurs,  and  is  often  known  as  "  cross-bite  ". 
The  mandible  usually  exhibits  lateral  deviation, 
as  shown  by  the  relation  of  the  inter-space 
between  the  central  incisors  in  the  upper  and 
lower  arches,  and  at  the  point  of  crossing  there 
may  be  an  edge  to  edge  occlusion,  or  an  inter- 
locking facilitated  by  rotation  of  an  upper  in- 
cisor. In  these  cases  the  real  error  is  often  mainly 
on  the  apparently  normal  side,  and  expansion 
of  the  upper  arch  on  that  side  is  necessary  to 
permit  the  correction  of  the  deviation  of  the 
mandible.     As  a  secondary  result  of  the  faulty 

'  It  is,  of  course,  here  assiuned  that  the  normal  number 
of  teeth  are  present.  The  condition  is  a  natural  result 
of  absence  of  some  of  the  teeth.  The  writer  has  experi- 
ence of  such  a  case.  See  also  J.  L.  Courrier,  Dental 
Cosmos,  July  1911. 


135 


occlusion   on   the   other   side   there   is   usually 

some  displacement  of  the  upper  canine  or  other 

individual    teeth.     The    deformity    sometimes 

commences  in  the  deciduous  dentition,  and  an 

example   is   figured   in   the  next 

section  from  the  ^vriter"s  practice, 

in    which    the    first    cause    was 

factitious,  and  the  condition  the 

outcome  of  habit.     Li  other  cases 

it  is  probable  that  misplacement 

of   one   or   two    individual   teeth 

and  consequent  malocclusion  may 

cause  deviation  of  the  mandible, 

and  that  contraction  of  the  upper 

arch  on  the  side  from  which  the 

mandible  deviates  follows  as  the 

result  of  interaction  of  the  cusps 

and  the   pressure    of  the    cheek. 

Contraction  of  the  mandible  on 

the  opposite  side  is  also  likely. 

Treatment. — The  treatment  of 
almost  all  cases  of  this  class 
affecting  several  teeth  resolves 
itself  into  expansion,  either  of  the  whole  upper 
arch,  or  of  one  side  of  the  upper  or  lower.  The 
deviation  of   the  mandible  can  then  be  easily 


of  a  removable  plate.  Retention  is  only  neces- 
sary for  a  short  period,  as  the  normal  interac- 
tion of  the  cusps  when  once  restored  prevents 
recurrence. 


Fig.  224. — Separation  of  deciduous  central  incisors 
by  abnormal  fraenimr  labii.  (Xorman  G. 
Bennett.) 

corrected  by  means  of  suitably  arranged  inclined 
planes  and  flanges  as  fixtures  to  the  upper 
buccal  teeth  on  one  or  both  sides,  or  by  means 


Fig.  225. — Proclination  of  upper  deciduous  incisors  and  retrocliuation  of 
lower  deciduous  incisors  due  to  thumb-sucking.     (G.  Northcrojt.) 


Part  IV 
Deciduous  Dentition 

It  has  seemed  best  to  consider  briefly  ab- 
normalities in  the  deciduous  dentition  after 
those  of  the  permanent  dentition.  This  may 
at  first  sight  appear  to  be  a  reversal  of  the 
logical  order  of  procedure,  but  examples  of 
the  latter  are  more  frequent  and  more  varied, 
and  afford  a  better  opportunity  of  taking  a 
comprehensive  survey  of  the  subject.  Further- 
more, in  discussmg  the  subject  from  the  aetio- 
logical  standpoint,  the  causation  of  many 
deformities  in  the  second  dentition  has  been 
found  in  defective  development  while  the  first 
teeth  are  still  in  place ;  and  it  becomes  easier 
to  try  and  go  back  a  little  further,  and  find  the 
relation  between  such  defective  development 
and  the  concrete  effects  of  it  manifested  at  so 
early  a  period  as  from  the  third  to  the  sixth 
years  or  earlier. 

Misplacements  due  to  local  causes  are  un- 
common, but  supernumeraries  and  malformed 
teeth  have  been  recorded.  Abnormal  fraenum 
labii  causes  separation  of  the  deciduous  in- 
CLSors  (see  Fig.  224),  and  the  condition  should 
receive  treatment  in  order  that  the  permanent 
incisors   may    have    an    opportunity    to    erupt 

normally. 

The  iiabit  of  finger-  and  thumb-suckuig  of 
course  affects  the  deciduous  incisors  in  a  maimer 
similar  to  that  in  which  it  influences  the  position 
of  the  permanent  incisors  when  the  habit  is 
continued  (see  Figs.  225,  226).  To  what  extent 
misplacement  of  the  deciduous  teeth  from  this 
cause  wUl  produce  a  similar  deformity  afterwards 
if  the  habit  has  ceased  is  uncertain.     In  any  case 


136 


the  habit  should  be  cured  as  soon  as  possible,  but 
it  is  probably  best  to  a^^ait  the  eruption  of  the 
permanent  meisors  and  then  apply  treatment 
if  necessary. 

Caries  of  approximal  surfaces,  especially  of 
molars,  allows  movement  of  adjacent  teeth  and 
the  development  of  a  faulty  occlusion,  which 
becomes  more  pronounced  with  the  eruption 
of  the  first  permanent  molars  and  later  teeth. 
Preventive  treatment  consists  in  fillmg,  with 
restoration  of  contour. 

Malpositions  of  mdividual  teeth,  such  as  slight 
rotation  of  one  or  more  uicisors  from  want  of 
space,  are  occasionally  seen  (see  Figs.  227,  228). 
These  are  probably  due  to  defective  bony  de- 
velopment dating  from  infancy.  Examples  are 
given  by  W.  M.  Dailey  (64). 

The  wTiter  refers  elsewhere  (see  pp.  114,  137  ; 
Figs.  190,  234,  235)  to  a  case  of  apparent 
inlieritance  of  abnormal  alignment  and  ex- 
cessive overbite  m  the  incisor  region.  North- 
croft  (122)  has  shown  several  examples  of 
excessive  overbite  among  twenty-five  children 


find  a  defuiite  post-normal  occlusion  to  the 
extent  of  one  unit,  though  examination  of  a 
large  number  of  children  would  probably  dis- 


FiG.  22G. — Protrusion  of  upper  deciduous  incisors  in 
patient  aged  3i  years,  due  to  thumb-sucking. 
The  figuTe.s  on  the  left  (tliree  months  later)  show 
the  result  of  treatment.  (W.  W.  James  :  Trans. 
B.S.S.O. ;  Dental  Record.) 

from  two  and  a  quarter  to  six  and  a  half  years 
of  age  (see  Fig.  241). 

By  far  the  most  important  defect  noticeable 
in  the  deciduous  dentition  (apart  from  the  ^^•ant 
of  spacing  m  the  anterior  region,  which  is  a 
certain  forerunner  of  later  deformity)  is  a  com- 
mencing faulty  occlusion  in  the  molar  region, 
in  which  the  lower  molars  are  posterior  to  the 
normal  position.     It  is  perhaps  more  rare  to 


Fig.  227. — Overlapping  upper  deciduous  central 

incisors.     (G.  Northcroft.)  ^  _r 

cover  a  good  many  cases  (see  Figs.  229, 2S0,  231). 
The  successfid  treatment  by  inter-maxillary 
force  of  such  a  case  due  to  adenoids  is  recorded 
by  Guilhermena  P.  Mendell  (116)  (see  Figs.  232, 
233) ;  the  subsequent  development  of  this  case 
(117)  was  not  so  satisfactory  as  might  have 
been  expected ;  but,  as  G.  P.  Mendell  remarks, 
this  was  very  likely  due  to  the  adenoids  having 
been  allowed  to  remain  because  they  were 
small  in  amount. 

The  usual  feature  is  a  gradual  development  of 
a  condition  in  which  each  molar  occludes  whoUy 
and  solely  with  the  corresponding  tooth  in  the 
ujjper  jaw.  It  is  natural  to  correlate  this  defect 
"ith  the  insufficient  anterior  spacing,  and  it  seems 
obvious  that  insufficient  growth  takes  jDlace  at 
the  condyle  and  angle  of  the  mandible  as  well 
as  in  other  parts  of  both  ja«s.  There  may  also 
be  insuificient  transverse  development  of  the 
upjjer  arch,  which,  as  has  been  said,  should 
normally  increase  in  width  during  the  period 


Fig.  228. — Rotation  and  Ungual  displacement  of  right 
lower  lateral  deciduous  incisor.     (G.  Northcroft.) 

of  the  deciduous  dentition,  and  it  is  probable 
that  the  factor  of  mouth-breathing  and  nasal 
stenosis  enters  thus  early  into  many  of  these 
cases.     In  considering  this  gradualdevelopraent 


\_ 


137 


of  faulty  molar  occlusion  it  must  be  remembered 
that  the  crowns  of  the  deciduous  molars  have 
flatter  surfaces  and  smaller  cusps  than  the 
permanent  teeth,  and  that  interlocking  scarcely 
exists,  especially  after  wear  of  the  cusps. 

Credit  is  due  to  G.  Northcroft 
(119)  for  emi^hasizing  the  import- 
ance of  seeking  the  commencement 
of  what  will  be  a  post-normal 
occlusion  of  the  permanent  teeth 
in  faulty  occlusion  of  the  decidu- 
ous molars.  Among  twenty  cases 
of  abnormality  in  the  deciduous 
dentition  before  the  eruption  of 
the  first  permanent  molars,  he 
found  six  cases  showing  post- 
normal  occlusion.  He  further 
points  out  that  the  average  medio- 
distal  width  of  the  lower  decidu- 
ous molars  is  r4  mm.  greater 
than  that  of  the  upper,  and  that 
therefore  any  great  discrepancy 
between  these,  or  any  diminution  of  space  in 
the  upper  arch  caused  by  caries,  will  facilitate 
the  production  of  an  occlusion  in  which  the 
lower  teeth  are  posterior  to  normal  or  the  upper 
are  anterior  to  normal.     This  argument,  drawn 


result  of  the  deciduous  upper  centrals  erupting 
before  the  lower,  as  sometimes  happens.  The 
writer  has  observed  a  very  instructive  case 
(referred  to  on  pp.  114,  136,  as  an  example  of 
excessive  overlap  in  the  incisor  region)  in  which 


Fig. 


229. — Inferior  retrusion.       Post-normal  occlusion  (one   unit)   of 
deciduous  arch  in  very  young  patient.      (Harold  Chapman.) 


from  a  consideration  of  the  teeth  themselves,  is 
interesting  as  affording  an  additional  explana- 
tion to  that  derived  from  insufficient  mandi- 
bular development  about  the  angle  and  condyle. 
Northcroft  has  also  drawn  attention  to  the 
possibility  of  faulty  occlusion  occurring  as  a 
5  * 


Fig.  230. — Inferior  retrusion  and  secondary  proclination  of  upper  incisors. 
Lower  deciduous  arch  post-normal  (one  unit),  molars  also  lingual. 
(Harold  Chapman.) 

the  upper  mcisors  erupted  first  and  exhibited  an 

abnormal  alignment,  almost  certainly  inherited 

with    the    edges    directed    unduly    backwards, 

instead  of  vertically.     A  post-normal  occlusion 

of   the   entire    lower   arch    followed   almost    of 

necessity  from  thLs   condition 

(see  Figs.  234,235).  The  proper 

treatment  for   such  a  case  is 

plainly  to  correct  the  deciduous 

upper  incisors  before  the  age  of 

six,    and    at    least    afford    an 

opportunity,  with  the  wear  of 

the  molar  cusps,  for  the  lower 

jaw  to  move  forward  and  allow 

the  first  permanent  molars  to 

achieve  a  normal  occlusion  (see 

Fig.  236). 

Harold  Chapman  (46),  in  an 
excellent  study  of  the  decidu- 
ous   dentition,    expresses    his 
belief     that    the    discrepancy 
between  the  medio-distal  width 
of  the  upper  and  lower  molars 
is  greater  than   14  mm.,  and 
that  the  distal  margin  of  the 
second  lower  is  but  little  if  at 
all  anterior  to  the  distal  margin 
of    the   second    upper    molar. 
He  deduces  from  this  that  the 
first    lower    permanent    molar 
must  move  forward  more  than 
the    upper  molar   to    produce 
normal    occlusion.      However, 
it  is  probable  that  such  examples   cannot   be 
regarded  as  normal,  and  that  in  any  case  the 
downward  and  forward  rotatory  movement  of  the 
first  upper  permanent  molar  during  eruption  will 
generally  ensure  locking  of  the  cusps  with  the 
lower.     It  should  be  remembered  that  the  lower 


lowt 


138 


usually,  though  not  always,  erupts  first.  The 
early  development  of  post-normal  occlusion  in 
connection  with  tlie  differences  m  size  between 


for  treatment  for  such  young  children,  when 
so  much  depends  upon  the  character  of  the 
mdividual.  An  attempt  should  usually  be  made 
to  remedy  as  soon  as  possible  such  gross 
deformities  as  those  just  described. 

Improved  knowledge  of  the  aetiology  of 
abnormalities  of  occlusion  tends  to  show  with 
increasing  force  the  importance  of  early  treat- 
ment. Only  a  few  years  ago  arguments  were 
directed   to   show   that   treatment   should   not 


Fig.  231. — Skull  sliowing  post-normal  occlusion  of 
lower  deciduous  molars.  (Harold  Chapman  : 
Trans.  B.S.S.O.  ;  Denial  Record.) 

the  deciduous  and  permanent  teeth  is  discussed 
by  Simms  (141). 

As  regards  other  gross  deformities  Paton 
Pollitt  (131)  has  recorded  a  very  rare  case  of 
pre-normal  occlusion  (see  Fig.  237). 

Cases  of  buccal  and  lingual  malocclusion  are 
occasionally  seen.  An  interesting  example  in 
a  boy  of  five  occurred  in  the  writer's  ex- 
perience ;  the  lower  arch  was  deflected  to 
the  left,  and  the  left  side  was  in  buccal 
occlusion  with  the  upper,  and  the  "crossing" 
occurred  at  the  region  of  the  left  lateral  (see 
Fig.  238).  The  real  defect  consisted  in  narrow- 
ness of  the  upper  arch,  which  needed  expansion 
on  the  right  side,  after  which  reduction  of  the 


Fig.  232. — Inferior  retrusion  and  secondary  proclination  of  upper  incisors  in  patient 
aged  3} 5  years.  Lower  molars  in  post-normal  occlusion  (one  unit).  (G.  P. 
Mendell  :   Denial  Cosmos.) 

mandible  and  correction  of  occlusion  were  easily 
effected.  Somewhat  similar  cases  are  recorded 
by  C.  R.  Fitch  (75)  and  G.  Northcroft  (121) 
(see  Figs.  239,  240,  241,  230). 

Treatment. — It  is  diflBcult  to    lay  down  rules 


Fig.  233.-  I'oriiait  ..f  L;isr  sIm.hii  ni  Fig.  232.      (Dental 
Cof<inos.) 

be  deferred  until  the  tenth  or  twelfth  years,  as 
was  commonly  the  practice,  and  L.  S.  Lourie 
(109)  produced  convinc- 
ing examples  of  the  ad- 
vantages of  treatment 
about  the  sixth  to 
eighth  years.  At  the 
present  time  good 
reasons  are  advanced 
for  treatment  of  the 
deciduous  dentition. 

As  regards  commenc- 
ing  post-normal   occlu- 
sion the  first  essential  is 
that  growth  should  be 
stimulated   by   rational 
methods  of  feeding  and 
living,  as  without  this  no 
mechanical      treatment 
is   likely  to   avail.     Expansion  of  the  arches, 
when  necessary,  can  usually  be  accomplished 
for  quite  young  children — of  five  years  of  age 
or  less ;  and  a  biting  plate  with  inclined  plane 
to  occlude  with  the  lower  incisors  is  probably 


Fig.  234. — Inferior  retrusion  and  secondary  retroclination  of  upper  incisors  associated  with 
wide  arches  in  patient  aged  5/%  years.  Lower  molars  in  post-normal  occlusion  (one 
unit.)     Excessive  overbite  of  incisors.     (Norman  G.  Bennett.) 


Fig.  235. — Portraits  of  case  shown  in  Fig.  234.     [Trans.'^B.S.S.O. ;  Dental  Record.) 


140 


the  best  means  of  combating  the  commencing 
faulty  occlusion. 

In  two  interesting  articles  J.  Lowe  Young 
(176)  (177)  discusses  the  advantages  of  treatment 


UPPER. 


L.     L 


M  1 


M  2 


Centimetre    Scale. 


LOWER. 


M  1.1 


M  2. 


Centi/netre'  Scale. 

Fio.  236. — Diagram  tojillustrate  growth  o£  the  jaws 
and  increase  in  size  of  the  arches  in  one  year 
(5i-6i  years),  in  case  shown  in  Figs.  234,  235. 
A  bow  had  been  6tted  to  the  upper  arch  and  the 
incisors  and  canines  drawn  forward.  Nothing 
had  been  done  to  the  lower  arch.  L  represents 
the  distance  between  the  medio-occlusal  angles 
of  the  laterals,  C  between  the  cusps  of  the  canines, 
MI  between  the  medio-buccal  cusps  of  the  first 
molars,  and  M2  the  second  molars.  The  shorter 
length  in  each  instance  is  from  the  casts  at  5i 
years,  and  the  longer  at  6i' years.  The  vertical 
hnes  on  the  right  of  the  diagram  represent  the 
distance  from  a  point  betw^een  the  medio-occlusal 
angles  of  the  centrals  to  the  centre  of  a  line  joining 
the  posterior  surfaces  of  the  second  molars.  Note 
that  the  increase  in  dimensions  in  the  mandible 
is  practically  the  same  proportionally  as  in  the 
maxilla,  except  in  the  antero-posterior  distance 
where  no  increase  occurred.  ■■  However,  the  man- 
dible failed  to  come  forward  into  normal  occlusion, 
and  inter-maxillary  force  will  probably  be  required. 

of  the  deciduous  arches  at  about  six  years  of 
age,  when  growth  of  bone  has  been  insufficient 
to  produce  the  proper  spacing  between  the 
anterior  teeth,  and  malposition  of  the  per- 
manent   teeth    can    be    confidently    predicted. 


Fig.  237. — Inferior  protrusion  in  boy  aged  4|  years, 
pre-normal  occlusion  of  lower  arch.  The  father 
has  an  edge-to-edge  bite  and  two  uncles  have 
inferior  protrusion.  Both  upper  and  lower  in- 
cisors are  spaced ;  in  the  case  of  the  upper  this  is 
remarkable,  considering  the  retrocLination.  (G. 
Paton  PoLLiTT  :   Trans.  B.S.S.O. ;  Dental  Record.) 


141 


His  examples  show  that  after  early  correction 
the  permanent  teetli  erupt  into  normal  align- 
ment ;  but  the  point  that  in  the  writer's  opinion 


Fio.     23S. — Buccal    occlusion    of    left    lower    lateral, 
canine,   and  first  and   second  molars,   and  de\aa- 
tion   of  mandible   to  left   side.     Both  arches   are 
fairly  developed,  but  the  right  upper  molars  are 
too    far    lingual.     The    condition    probably   arose 
artificially  from  habit,  perhaps  encouraged  by  a 
small   displacement   of    the    left   upper   lateral. 
The  right  upper  naolars  then  probably  moved 
lingually  to  occlude  with  the  lower.     Treatment 
consisted  first  in  moving  these  upper  molars  in 
a  buccal   direction,  after  which  it  was  easy  to 
correct   the   deviation  of   the  mandible  and  to 
move  the  left  upper  lateral  and  canine  outwards. 
The   left   upper  molars  icere  not   moved,  and   a 
perfect  result  was  acliieved.     Removable  appli- 
ances were  used.     (Norm.\n  G.  Bennett.) 

remains  to  be  proved,  is  \^hether  in  all  cases, 
or  even  a  majority,  of  children  of  poor  physique 
the  stimulus  to  growtli  afforded  by  mechanical 
interference  will  be  sufficient,  and  bony  de- 
velopment properly  correlated  ^\ith  normal 
dental  occlusion.  The  preat  advantages  of 
early  treatment  are  otherwise  obvious,  and  as 
regards  post-normal  occlusion  of  the  lower 
arch  in  the  deciduous  dentition,  there  can  be 
little  doubt  that  the  sooner  it  can  be  remedied 
the  greater  will  be  the  probability  of  the  per- 
manent teeth  coming  into  normal  occlusion.  A 
valuable  discussion  on  early  treatment  (176) 
followed  the  reading  of  these  papers. 

The  advantages  of  earlv  treatment  are  also 


weU  explained  by  D.  H.  Willard  Flint  (76), 
who  freely  admits  the  merits  of  removable 
appliances  for  very  young  patients,  and  also 
by  E.  A.  Bogue  (30)  (31)  (34), 
Vamey  E.  Barnes  (21),  and  R. 
N.  PuDen  (135).  In  a  recent 
paper  Bogue  (33)  states  with 
great  clearness  and  cogency  the 
advantages  of  early  treatment 
of  deciduous  teeth  and  early 
removal  of  adenoids.  He  be- 
lieves that  malocclusion  of  the 
jsermanent  teeth  may  almost 
certainly  be  prevented  if  the 
deciduous  teeth  are  treated 
between  four  and  six  years  of 
age  ;  and  that  expansion,  when 
normal  spacing  is  insufficient, 
also  aids  the  prevention  of 
nasal  stenosis  and  correlated  deformities. 

In  an  earlier  but  interesting  paper  Barnes 
(20)  discusses  the  development  of  the  jaws 
during  the  period  of  eruption  of  the  deciduous 
teeth,  and  gives  many  illustrations  of  abnor- 
malities of  the  deciduous  dentition,  including 
deficient  spacing,  close  bite,  and  excessive  over- 
bite, and  deficient  development  about  the 
apices  of  the  teeth.  He  shows  clearly  the 
falsity  of  the'^idea  that  while  the  permanent 
teeth  succeed  their  predecessors  step  by  step,  the 
bone  only  develops  intermittently  around  each 
eruiDting  tooth.  There  can  be  little  doubt  that 
space  for  the  permanent  teeth  must  be  provided 
by  bony  growth  at  an  earlier  period,  although 
probably  this  takes  place  most  rapidly  in  different 
parts  of  the'  jaw,  at  different  times,  and  in  that 
sen.se  constitutes  sectional  development. 


Fig.  239. — Right  upper  teeth  from  deciduous  canine  to 
first  permanent  molar  in  lingual  occlusion;  deviation 
of  mandible  to  the  right.  This  case  differs  from  that 
shown  in  Fig.  238,  in  that  the  defect  in  the  upper 
arch  was  on  the  same  side  as  that  to  which  deviation 
of  the  mandible  occurred,  instead  of  the  opposite. 
(C.  R.  Fitch  :  Trans.  B.S.S.O.  ;  Dental  Record.) 

■  i  Barnes  is  of  opinion  that  the  bony  development 
of  different  portions  of  the  jaws  is  completed 
at  certain  ages,  and  he  therefore  emphasizes 
the  importance  of  early  treatment.  He  advises 
the  forward   movement   of  the  anterior   teeth 


142 


where  spacing  is  insufficient  at  four  to  six  years 
of  age,  including  the  movement  of  the  roots 


Fig.  240. — Lingual  occlusion  of  right  upper  canine  and 
molars  in  patient  aged  4j\  years.    (G.  Northckoft.) 

in  cases  where  development  is  iixsufficient 
around  the  apices  of  the  teeth.  This  must  be 
regarded  as  an  ideal  line  of^jtreatment,  and  one 

very  difficult  to  carry  out  ex- 

cept  in  selected  cases ;  and 
apart  from  this  difficulty  proof 
is  wanting  that  sufficient 
stimulus  to  bony  growth  is 
provided  without  change  of 
methods  of  feeding  and  general 
nutrition,  or  even  with  these 
advantages. 

The  elucidation  of  many  of 
the  unsolved  aetiological  prob- 
lems of  malposition  of  the  teeth 
probably  rests  with  an  exten- 
sive study  of  the  normal  and 
abnormal  development  of  the 
jaws   from  infancy  to  six  years  of  age. 

Accurate  measurements  such  as  those  under- 
taken by  G.  G.  Campion  (41)  are  essential  for 


this  purpose,  but  they  should  also  be  sufficient 
in  number  in  each  case  to  make  possible  a 
complete  reconstruction  of  the  form  of  the  jaws 
and  position  of  the  teeth.  The  writer  devised 
such  a  system  of  measurements,  but  the  in- 
accuracies caused  by  taking  some  of  them 
through  the  soft  parts  exceeded  the  limits  of 
variation  in  different  jaws.  The  difficulty  is 
probably  not  insuperable  and  undoubtedly 
contains  the  solution  of  some  of  the  problems 
of  aetiology.  Tlie  prosopometer,  designed  by 
Sim  Wallace  and  modified  by  G.  Northcroft, 
is  a  useful  instrument  for  obtaining  definite 
information  with  regard  to  relative  dimensions 
of  jaws  and  arches  (see  pp.  144,  145),  and  some 
of  the  results  of  its  application  are  found  in  the 
Report  of  the  Committee  of  the  British  Society 
for  the  Study  of  Orthodontics  on  "  Phenomena 
found  in  Post-normal  Occlusion ",  presented 
by  J.  G.  Turner  (157).  The  investigations  of 
Rushton  (139)  on  the  "  mandibular  and  profile 
angles  ",  and  his  methods  of  measurement,  have 
been  previously  referred  to  (p.  117).  A  piece 
of  apparatus  has  been  designed  by  Joh.  Groth 


Fig.  241. — Lingual  occlusion  of  right  lower  molars.     Excessive   overbite 
of  incisors.     (G.  Northceoft.) 

(81)  for  measuring  the  different  portions  of  the 
face  and  jaws,  the  angle  of  the  mandible,  and 
the  angular  relation  of  other  parts. 


CHAPTER    YT 


ABNORIVIALITIES   OF   POSITION    {continued) 


Paet  V 
Diagnosis 

It  has  been  already  remarked  that  similar 
causes  may  produce,  or  at  least  assist  iii 
producing,  very  different  types  of  abnor- 
mality; and,  on  the  other  hand,  that  cases 
that  appear  to  resemble  one  another  closely 
may  be  really  quite  diSerent  in  origm.  Only 
deformities  of  a  very  simple  type  can  be  traced 
to  the  action  of  a  single  cause.  In  most  cases 
the  effect  of  one  main  influence  in  producing 
some  deviation  from  normal  development  is 
assisted  or  opposed  by  various  minor  conditions 
or  contributory  causes.  Therefore  it  is  not  to 
be  wondered  at  that  the  task  of  analysmg  and 
defuiing  the  abnormalities  that  go  to  compose 
a  complex  case  is  often  difficult.  Still  more 
difficult  is  it  to  form  a  clear  picture  of  the 
aetiological  factors  that  have  been  at  work  :  the 
more  immediate  causes  may  be  fairly  obvious, 
but  an  attempt  to  find  the  real  origin  of  even  a 
well-defined  abnormality  usually  involves  some 
amount  of  speculation  and  gropmg  in  the 
dark.  Normal  arches  in  normal  jaws  are  the 
product  of  a  very  finely  adjusted  series  of 
changes  occurring  throughout  a  number  of 
years.  The  word  "normal"  itself  is  only  an 
average  term,  because,  in  cases  of  mixed 
origm  at  least,  various  modifications  of  type 
occur  that  cannot  be  classed  as  abnormalities ; 
but  outside  the  range  of  these  normal  variations 
certain  more  extreme  types  occur  that  are 
probably  due  more  to  genetic  variation  than  to 
external  influence.  However,  it  is  probably 
true  that  most  examples  of  marked  abnormality 
are  due  to  mfluences  arismg  during  the  period 
of  growth,  and  it  is  easy  to  understand  that 
with  so  fijiely  adjusted  a  process  any  inter- 
ference with  the  natural  course  of  events  may 
produce  results  quite  out  of  proportion  to  the 
magnitude  of  the  cause. 

It  is  necessary  that  methods  of  treatment 
should  not  run  counter  to  the  possibilities 
of  natural  development,  and  a  clear  under- 
standing of  \\hat  a  case  really  consists  in  is 
essential  for  scientific  treatment,  and  for  recog- 
nition of  the  extent  to  which  mechanical  means 
may  be  expected  to  compensate  for,  and  remedy, 
developmental  defects.  It  is  a  common  thing 
for  students  to  regard  a  case  too  much  at  the 


outset  from  the  point  of  view  of  treatment, 
and  to  prescribe  such  methods  as  will  have  the 
effect  of  correcting  some  more  or  less  obvious 
deformities.  This  method  is  analogous  to  the 
treatment  of  symptoms  of  medical  diseases ; 
a  patient  suffering  from  acute  rheumatism  may 
require  treatment  directed  to  the  reduction  of 
body  temperature,  another  suffering  from  pneu- 
monia may  need  oxygen  to  relieve  the  stress 
of  difficult  respiration,  but  the  treatment  of 
such  urgent  symptoms  takes  no  account  of  the 
real  nature  and  cause  of  the  disease,  and  the 
logically  correct  curative  treatment.  So  it  is 
with  abnormalities  of  the  teeth  and  jaws ; 
correct  diagnosis  is  a  necessary  preliminary  to 
rational  treatment,  and  a  more  thorough 
examuiation  of  an  apparently  rather  simple 
case  will  sometimes  show  that  the  teeth  that 
seem  at  first  sight  to  be  most  out  of  position 
are  really  the  only  ones  correctly  placed.  It 
should  not  be  inferred  from  this  that  every  case 
must  be  allotted  a  definite  place  m  any  scheme 
of  classification,  which  in  the  light  of  present 
knowledge  can  only  be  provisional ;  but  unless 
the  deviations  from  the  normal,  of  which  every 
case  consists,  can  be  and  are  described  accurately 
in  ^^ords,  it  may  usually  be  assumed  that  obser- 
vation and  diagnosis  are  at  fault.  It  would  be 
well  if  every  case  beyond  the  simplest  received 
attention  on  the  lines  of  "  case-taking  "  in  a 
hospital  ward :  definite  description  removes 
vagueness  of  idea. 

The  aim  of  the  student  should  bs,  then, 
firstly,  to  analyse  and  describe  in  detail  the 
abnormalities  that  present  themselves  ;  secondly, 
to  summarize  these  if  possible  by  classifymg 
the  abnormality  as  a  pure  type  or  combination 
of  types ;  thudly,  to  discover  the  immediate 
and  remote  aetiological  factors ;  fourthly,  to 
estimate  the  possibilities  of  treatment ;  and 
fifthly,  to  prescribe  the  exact  course  and  details 
of  treatment.  The  first  three  of  these  may 
fairly  be  included  under  diagnosis ;  the  last  two 
will  be  considered  in  subsequent  sections. 

In  order  that  a  just  appreciation  of  the  de- 
fects of  a  case  may  be  obtained  it  is  well  that 
examination  sliould  be  systematic.  Consider 
first  the  general  physique  of  the  child  and 
estimate  whether  the  gro^-th  and  development 
are  proportionate  to  the  age ;  then  study  the 
contour  of  the  face,  full  face  and  in  profile, 
and  note  whether  there  is  any  appearance  of 
143 


144 


narrowness  of  the  maxilla,  and  whether  the  lips 
and  chin  are  in  a  more  or  less  normal  relationship 
with  the  upper  part  of  the  face,  the  forehead, 
bridge  of  the  nose,  and  malar  prominences. 
See  whether  there  is  any  prominence  or  recession 
of  the  lips,  and  whether  such  modifications 
affect  the  margins  of  the  lips,  or  the  attachments 
beneath  the  alae  of  the  nose  and  at  the  mento- 
labial  fold,  which  correspond  to  the  apices  of 
the  upper  and  lower  incisors  respectively. 
Note  the  depth  and  definition  of  the  naso-labial 
and  mento-labial  lines.  Observe  whether  the 
lips  come  easily  or  too  easily  together  in  natural 


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Fig.   242.— (Trans.  B.S.S.O. ;  Denial  Feconl. 


pose,  or  whether  the  teeth  can  be  seen.  Study 
the  shape  of  the  mandible,  and  especially  the 
degree  of  obliquity  of  the  angle. 

Intelligent  external  examination  of  this  kind 
will  enable  a  shrewd  guess  to  be  made  as  to  the 
likelihood  of  dental  abnormality,  and  its  general 
character,  before  the  mouth  is  opened.  Then 
take  note  of  any  marked  malposition  of  indi- 
vidual teeth,  consider  the  shape  of  each  arch 
separately,  and  study  the  occlusion.  The  test 
teeth  of  occlusion  are  the  first  permanent  molars, 
but  the  possibility  of  forward  movement  of  one 
or  more  must  be  remembered. 

Notice  whether  there  is  any  marginal  gingi- 
vitis suggestive  of  mouth-breathing,  and  finally. 


in  cases  where  observation  suggests  the  possi- 
bility of  this  habit,  examine  the  tonsils  and 
pharynx,  and  make  inquiries  as  to  nasal  stenosis 
and  "the  presence  of  adenoids.  Inquire  also, 
when  necessary,  as  to  any  other  harmful  habits 
and  methods  of  feeding  in  early  years. 

In  cases  of  a  simple  order  it  \\  ill  be  possible  to 
define  and  classify  the  deformity  at  a  single 
sitting,  but  in  other  cases  careful  study  of 
casts,  followed  by  corroboration  of  first  im- 
pressions at  a  second  sitting,  will  be  necessary. 
The  greatest  difficulties  occur  in  connection 
with  Classes  II  and  III.  In  cases  of  so-caUed 
"  crowding  "  (an  expres- 
sion of  so  vague  a  signifi- 
cance as  to  merit  disuse) 
it  is  necessary  to  judge 
whether  the  misplace- 
ment of  certain  teeth  is 
due  to  deficient  bony 
development  at  that  part 
of  the  arch,  or  whether 
early  deficiency  has  paved 
the  way  for  difficulties 
in  connection  with  later 
teeth  in  another  part  of 
the  arch.  Where  the 
occlusion  of  the  first  per- 
manent molars  is  abnor- 
mal, it  is  necessary  to 
consider  whether  this  is 
due  to  translation  of 
molars  consequent  on 
prematura  loss  of  decidu- 
ous molars,  or  to  the 
more  deep-seated  causes 
already  discussed.  When 
there  exists  a  false  re- 
lationship of  the  two 
arches,  judgement  is  re- 
quired to  tell  which  is 
abnormally  placed,  and 
the  facial  contour  must 
be  taken  into  account. 
The  use  of  the  prosopo- 
meter (see  Figs.  242,  243, 
244),  and  the  estimation  of  the  mandibular  and 
profile  angles  (Rushton,  see  pp.  117-119),  are 
very  desirable.  It  has  been  explained  that 
prominence  of  the  upper  incisors  may  be  due  to  a 
variety  of  causes,  and  that,  in  point  of  fact,  cases 
presenting  this  feature  may  be  fundamentally 
different :  it  is  important,  therefore,  to  find  out 
whether  this  is  the  cardinal  and  only  defect, 
or  whether  it  is  a  secondary  result  of  other 
abnormalities. 

Enough  has  been  said  to  show  that  careful 
study  and  deliberation  are  needful  to  place 
correctly  any  but  the  simplest  types  of  defor- 
mity ;  but  methods  of  treatment,  to  have  any 
prospect    of   success,    must    be    founded    upon 


PffOiOPOtC  t£a 


145 


definite  observation,  and,  as  far  as  the  present 
state  of  knowledge  permits,  upon  an  estimate  of 
the  aetiological  factors  involved  in  the  case. 

Pakt  VI 

General  Objects  of  Treat- 
ment and  Modifying  Cir- 
cumstances 

Ideal  treatment 
obviously  consists  in  the 
restoration  of  normal 
alignment,  normal  con- 
formation of  each  arch, 
normal  occlusion  of  the 
two  arches,  and  normal 
contour  of  the  dento -facial 
area ;  several  considera- 
tions combine  to  prevent 
this  consummation  being 
attained  in  many  cases, 
or  even  to  warn  the  wise 
operator  from  attempting 
it.  In  the  first  place,  it 
has  been  sliowii  that  varia-  _y.'''' 

tion     of     type     provides  ,.■■■ 

much  diversity  within  so- 
called  normal   limits,   and   in   individual  cases 
where  the  deviation  from  type  is  sufficiently 
marked  to  justify  the  term  abnormal,  it  is  not 


one  preconceived  ideal  must  produce,  and 
often  has  produced,  very  unsatisfactory  results  ; 
the  size  and  shape  of  arch  that  would  accord 


Fiu.   243.— (Tmns.  B.S.S.O.  ;  Dental  Record. 


always  possible  to  judge  what  the  normal  for 
that  particular  case  should  really  have  been. 
Any    attempt    to    reduce    all    abnormalities   to 


Fig.  2-14. — [Trans.  B.S.S.O.  ;  Dental  Record.) 

well  with  one  face  would  be  inharmonious  in 
another. 

Estimation  of  Arch. — Nevertheless,  if  allowance 
be  made  for  personal  judgement  in  individual 
eases,  much  assistance  may  be  gamed  by  an 
artificial  predetermination  of  a  corrected  arch 
in  picturing  the  results  of  expansion  of  a  very 
irregular  arch  and  reduction  to  normal  occlusion 
of  misplaced  teeth. 

Hawley  (85)  (87)  has  devised  a  method  based 
upon  the  dictum  of  Bonwill  (132,  p.  554)  that 
the  t^^'o  condyles  and  the  medial  point  of  con- 
tact of  the  central  incisors  form  an  equilateral 
triangle  of  which  the  side  varies  in  different 
cases  between  three  and  five  inches.  His 
method  Ls  as  follows  (see  Fig.  2'45) — 

Measure  the  \^idth  of  a  central  incisor,  lateral 
incisor,  and  canine.  Let  the  combined  width  V)e 
A  B.  From  B  as  centre  describe  a  circle  with 
this  as  radius.  From  any  point  A  mark  two 
points  on  the  circle  J,  H,  so  that  the  chords 
A  J,  A  H  equal  the  radius  A  B.  Produce  A  B 
to  cut  the  circle  at  C.  Join  C  J  and  C  H. 
Draw  a  tangent  to  the  cu'cle  at  A,  to  cut  C  J 
and  C  H  produced  in  E  and  D,  and  form  the 
equilateral  triangle  C  D  E.  On  A  C  produced 
mark  A  I  equal  to  D  E,  and  from  I  as  centre 
and  with  A I  as  radius  describe  a  circle. 
Within  this  circle  inscribe  the  equilateral 
triangle  A  F  G.  Join  F  J,  and  G  H,  on  A  J 
and  A  H  measure  off  widths  equal  to  the 
widths  of  the  central,  lateral  and  canine,  and 
from   J  F,   H  G   measure   off   J  K,   and  H'L, 


146 


equal  to  the  combined  widths  of  the  premolars 
and  molars.  Then  the  curve  K  J  A  H  L  repre- 
sents the  arch,  and  F,  G,  the  condyles.  The 
circular  arc  J  A  H  is,  of  course,  sUghtly  longer 


FiQ.  245. 

than  the  total  width  of  incisors  and  canines, 
because  the  chords  A  J,  A  H  equal  that  width, 
but  the  slight  difference  is  not  of  much  practical 
importance. 

Hawley  gives  no  explanation  of  his  reason 
for  taking  one  side  of  the  triangle  C  D  E  as  the 
radius  of  the  large  circle  A  F  G.  As  a  matter 
of  fact  it  may  be  shown  mathematically  that 
A  F  or  AG,  a  side  of  the  BonwiLl  equilateral 
triangle,  is  four  times  A  B,  the  radius  of  the 
small  circle,  and  Hawley 's  diagram  may  be 
produced  in  a  much  simpler  way  as  follows  (see 
Fig.  246)— 

Describe  a  circle  from  centre  B,  with  radius 
A  B  equal  to  the  combined  widths  of  central, 
lateral,  and  canine.  Draw  B  J  at  an  angle  of 
60°  with  B  A,  to  cut  the  circle  at  J,  and  on  the 
other  side  of  B  A  draw^B  H  in  a  similar  manner. 
Extend  B  A,  and  draw  tangents  to  the  circle 
at  J,  H  at  angles  of  20°  to  B  A,  meeting  B  A 
produced  at  a  point  0.  Extend  O  J,  0  H  to 
F,  G,  until  A  F,  A  G  equal  F  G.  From  J,  H 
measure  J  K,  H  L,  equal  to  the  combined  widths 
of  the  premolars  and  molars.  Then  K  J  A  H  L 
as  before  represents  the  arch,  and  F,  G,  the 
condyles. 

Hawley 's  method  is  in  fact  founded  on  several 
assumptions — 

(a)  The  six  front  teeth  range  round  a  circular 

arc  subtending  at  the  centre  an  angle 
of  120°. 

(b)  The   premolars   and   molars   range   along 

two  approximately  straight  lines  sloping 
at  an  angle  of  20°  with  the  median  line. 


(c)  The  total  width  of  all  the  teeth,  or  in 
other  words  the  dental  arch,  bears  a 
constant  relation  to  the  size  of  the 
maxUla  or  mandible  and  the  face 
generaDy. 

{d)  The  shape  of  the  arch  is  constant  for  all 
individuals  m  different  races. 

(e)  The  two  condyles  and  the  median  point 
between  the  central  incisors  lie  at  the 
apices  of  an  equUateral  triangle  whose 
sides  are  equal  to  four  times  the  com- 
bined \vidth  of  a  central,  lateral,  and 
canine. 

With  regard  to  (d),  Hawley,  it  is  true,  em- 
phasizes the  elasticity  of  his  method  and  allows 
for  modification  by  judgement  of  the  form  of 
an  individual  arch  according  to  the  require- 
ments of  the  face,  but  the  diagram  itself  involves 
the  assumption. 

If  these  objections  are  borne  in  mind,  the 
figure  forms  a  convenient  method  of  gauging 
the  possibilities  of  treatment  and  estimating 
the  effect  on  the  face  of  an  expanded  and  cor- 
rected arch,  as  compared  with  one  diminished 
in  size  by  extraction.  But  even  then  it  must 
be  remembered  that,  if  this  ideal  arch  or 
canonical  figure  be  taken  as  approximately 
correct,  there  is  no  means  of  showing  the  proper 


Fig.  246. 

correspondence    between    the    arch    and    the 
maxilla  or  mandible  of  which  it  forms  a  part. 

In  order  to  save  time  and  trouble  in  preparing 
diagrams  for  every  case,  Hawley  has  had  prepared 
a  set  of  diagrams  corresponding  in  width  to 
different  widths   of  incisors  and  canines,  and 


147 


transferred  to  transparent  celluloid  according 
to  the  suggestion  of  L.  P.  Bethel.  The  celluloid 
placed  on  the  occlusal  surfaces  of  the  teeth  on 
the  model  shows  the  effect  of  expansion,  but 
does  not  show  what  should  be  the  ultimate 
antero-posterior  position  of  the  whole  arch  in 
the  jaw.  Somewhat  similar  diagrams  have 
been  designed  by  Herbst. 

In  order  to  provide  for  those  cases  in  which 
treatment  is  undertaken  before  the  eruption 
of  the  laterals  and  canines,  Hawley  has  made 
measurements  of  a  large  number  of  cases  to 
find  the  limit  of  variation  in  the  other  teeth 
for  a  central  of  known  width,  and  gives  the 
average  combined  width  of  central,  lateral, 
and  canine  corresponding  to  centrals  of  varying 
widths. 

As  a  guide  to  the  size  of  the  unerupted  teeth  ' 
he  takes  the  first  permanent  molar,  and  when 
this  exceeds  m  width  the  average  measurement 
corresponduig  to  a  particular  width  of  central, 
uses  the  next  longer  diagram,  and  vice  versa  in 
the  case  of  a  molar  smaller  than  average.  It  is 
probable  that  some  correspondence  does  exist 
between  the  width  of  the  first  molars  and  the 
other  teeth,  but  Hawley 's  figures  do  not  al- 
together support  his  contention.  If  the  size  \ 
of  the  first  molar  as  well  as  of  the  central  is  to 
be  considered  in  estimating  the  size  of  the  arch, 
it  would  be  better,  and  quite  possible,  to  com- 
pute average  radii  (from  ^\■hich  to  make  the 
diagrams)  from  the  combined  widths  of  the  two 
teeth.  This  would  be  preferable  to  the  un- 
certam  method  of  computing  the  radius  from 
the  known  width  of  the  central  and  average 
measurement  of  lateral  and  canme,  and  then 
readjusting  this  radius  mdefinitely  according 
to  the  known  width  of  the  first  molar. 

Alfred  Korbitz  (101 )  attaches  much  importance 
to  determining  the  ideal  form  of  the  arch  along 
the  buccal  surfaces  of  the  mandibular  teeth  ;  but 
his  system  of  geometrical  construction  is  em- 
pirical, if  not  indeed  based  on  pure  hypothesis. 
His  method  has  been  further  explained  by  Harold 
Chapman  (47). 

G.  G.  Campion  (41)  has  made  a  large  number 
of  measurements  of  diff'erent  skulls  to  show  the 
ratio  between  the  length  and  breadth  of  the 
arch ;  and  also  the  ratio  between  the  breadth 
of  the  arch  between  the  first  premolars,  and  the 
width  of  a  central  incisor.  The  average  of  the 
latter  ratio  is  about  5'3,  but  the  variation  is 
from  4'3  to  6'4.  His  results  are  much  in  accord 
with  Hawley's,  and  show  that  while  measure- 
ment of  a  single  tooth  may  be  of  use  for  pre- 
determination of  the  size  of  the  arch,  it  cannot 
be  relied  upon  as  a  definite  value.  A.  Pont  of 
Lyme  was  the  first  to  publish  investigations  in 
the  relationship  between  the  size  of  the  teeth 
and  the  size  of  the  arch,  and  his  results  are  given 
in  the  Report  of  the  Committee  on  the  Normal 


Arch,  appointed  by  the  British  Society  for  the 
Study  of  Orthodontics. 

Extraction  and  Mechanical  Treatment. — Gener- 
aUy  speaking,  abnormalities  m  position  of  the 
teeth  not  associated  with  defective  bony  de- 
velopment beyond  the  alveolus  belonging  to 
the  misplaced  teeth,  can  be  and  should  be  cor- 
rected by  mechanical  means  without  extraction. 
Unfortunately  these  cases  form  the  minority, 
and  the  difficult  problem  than  arises  whether, 
even  though  the  dental  abnormality  be  cor- 
rected, osseous  development  in  subsequent 
years  will  compensate  for  early  defect.  In  the 
opinion  of  the  writer  this  question  must  often 
be  answered  in  the  negative,  and  extraction 
then  becomes  a  logical  part,  or  sometimes  the 
•  whole,  of  the  course  of  treatment.  Even  in 
'  cases  where  defect  of  bony  development  is  slight, 
or  likely  to  be  remedied  by  subsequent  growth, 
much  forward  movement  of  molars  and  mis- 
placement of  premolars  or  canines  may  demand 
extraction  as  a  more  reasonable  course  than  an 
extensive  movement  of  several  teeth  by  artificial 
means  without  adequate  advantages.  Many 
cases  of  close  or  open  bite  and  of  antero-posterior 
malocclusion  present  great  difficulties,  and 
although  remarkable  results  have  been  obtamed, 
the  question  remains  whether  an  extensive 
translational  movement  of  several  teeth  is 
always  justifiable — whether,  in  fact,  "  the  game 
is  worth  the  candle ".  The  principle  of  ex- 
traction for  certain  classes  of  abnormalities 
considered  in  detail  in  previous  sections  has 
always  been  strongly  supported  by  C.  S.  Case 
(43)  (45,  p.  137)  as  not  merely  justifiable  but 
correct  procedure,  and  in  a  recent  article  (45, 
p.  276)  he  again  urges  his  views  with  much 
reasonableness  and  vigour.  Before  the  question 
can  be  answered,  time  must  show  to  what  ex- 
tent results  of  elaborate  mechanical  treatment 
are  really  permanent,  and  whether  extensive 
artificial  movement  does  not  predispose  to 
periodontal  disease  and  degenerative  changes 
of  the  pulps.  Even  apart  from  these  con- 
siderations, the  fact  remains  that  treatment  of 
difficult  cases  must  be,  even  in  the  hands  of  the 
most  expert  operator,  prolonged  and  at  least 
unpleasant,  and  that  mastication  is  somewhat 
interfered  with.  Then  the  use  of  the  apparatus 
itself,  especially  fixed  bands,  may  be  the  initial 
source  of  irritation  in  the  commencement  of 
periodontal  disease.  In  the  present  state  of 
knowledge  it  is  impossible  to  be  dogmatic  on 
these  points,  but  each  case  must  be  judged  on 
its  merits  with  reference  to  the  individual. 
\Vliat  is  possible,  justifiable,  or  even  easy,  in 
the  case  of  a  vigorous  healthy  child,  may  be  out 
of  the  question  witli  a  delicate  neurotic  child ; 
not  only  may  the  fittmg  and  wearing  of  either 
fixed  or  removable  apparatus  be  impossible,  but 
even  if  it  is  not,  the  effect  on  the  general  health 


148 


may  be  sufficiently  harmful  to  render  the  treat- 
ment very  inadvisable.  Girls  are  as  a  rule  , 
more  amenable  patients  than  boys  ;  the  demands  j 
of  school  time  are  a  smaller  impediment  to 
successful  treatment ;  and,  at  least  as  regards 
aestlietic  results,  elaborate  treatment  is  more 
justifiable,  by  virtue  of  the  greater  importance 
of  personal  beauty  in  women  than  men.  On  the 
other  hand,  their  nervous  system  is  usually  less 
stable,  and  they  will  be  less  likely  to  stand 
without  ill  effects  any  very  prolonged,  painful, 
or  disconcerting  method  of  treatment.  [ 

Wien  extraction  is  adopted  as  the  sole  or 
more  important  factor  in  treatment,  it  is  im- 
portant to  bear  in  mind  the  question  of  cusp 
relationship.  In  cases  of  normal  antero-pos- 
terior  relationship  of  the  arches,  as  a  general 
rule  the  same  number  of  cusps  should  be 
removed  from  the  upper  and  lower  arches  on 
the  same  side,  i.  e.  an  upper  and  lower  pre- 
molar, or  upper  and  lower  molar ;  otherwise, 
even  after  the  remaining  teeth  have  been 
moved  into  the  best  possible  cusp  relationship, 
there  will  be  redundant  cusps  in  one  or  other 
jaw,  having  no  proper  oi^iJonents.  This  is  a 
serious  defect.  On  the  other  hand,  in  cases, 
for  instance,  of  post-normal  position  of  the 
lower  arch,  where  this  is  not  to  be  corrected 
by  mechanical  means,  the  cusps  of  an  upper 
premolar  are  already  jiartly  unopposed,  and  it 
is  correct  to  extract  from  the  upper  jaw  only ; 
in  that  ^^ay,  after  subsec^uent  treatment,  a 
satisfactory  inter -digita ting  occlusion  can  be 
achieved. 

Complications  caused  by  Caries. — Something  lias 
been  said  in  former  sections  on  the  modifica- 
tion of  treatment  required  by  the  existence  of 
extreme  caries  in  one  or  more  teeth.  It  is 
obvious  that  hard-and-fast  rules  cannot  be  laid 
down,  and  that  judgement  must  be  exercised 
with  regard  to  each  individual  case ;  but  certain 
general  principles  should  be  borne  in  mind. 

The  modifications  of  treatment  necessary  at 
the  ages  when  interference  is  or  should  be  called 
for  are  usually  occasioned  by  caries  of  the  first 
permanent  molar.  When  the  caries  has  not 
reached  the  pulp  those  teeth  should  almost 
always  be  preserved,  even  though  the  extraction 
of  a  sound  premolar  is  demancled  by  the  course 
of  treatment  that  \\ould  be  adopted  if  all  the 
teeth  were  sound  ;  on  the  other  band,  exposure 
and  death  of  the  molar  pulp  before  the  age  at 
which  the  root  is  fully  calcified  usually  demands 
extraction.  There  is  little  hope  of  saving  such 
teeth  permanently,  and  it  is  Ijetter  to  extract 
them  at  a  period  when  natural  and  artificial 
means  may  be  brought  to  bear  in  compensating 
for  their  loss,  than  to  wait  until  loss  would  entail 
irreparable  damage.  In  some  cases,  however, 
it  may  be  desirable  to  preserve  them  for  a  time, 
so  as  to  extract  at  the  most  favourable  period. 


The  intermediate  condition  of  exposed  pulp 
after  complete  calcification  of  the  root  often 
presents  much  difficulty  for  the  operator  in 
coming  to  a  decision.  Two  distinct  classes  of 
case  must  be  considered  :  those  in  which  the 
ordinary  plan  of  treatment  would  involve  ex- 
traction of  another  tooth,  such  as  a  premolar, 
and  those  in  which  extraction  would  not  usually 
be  required.  Among  the  former  are  many 
cases  of  misplaced  canines  and  premolars 
occasioned  by  forward  translation  of  the  molars 
or  by  insufficient  osseous  growth,  and  cases  of 
true  suf)erior  protrusion  and  inferior  protrusion ; 
and  among  the  latter  are  many  cases  of  antero- 
posterior malocclusion.  Generally  speaking,  it 
may  be  said  that  where  extraction  is  ordinarily 
required,  molars  with  exposed  pulps  should  be 
extracted,  and  the  adjacent  teeth  moved  to  fill 
their  places,  but  this  cannot  be  regarded  as  an 
invariable  rule.  On  the  other  hand,  in  cases 
of  pure  inferior  retrusion,  the  loss  of  a  lower 
molar  where  the  mandible  or  lower  teeth  are 
already  too  far  back  is  a  serious  mutilation,  and 
every  effort  should  be  made  to  save  these  teeth 
by  filling  or  crowning.  The  same  observation 
applies  to  upper  molars  in  cases  of  superior 
retrusion.  In  other  cases  of  antero-posterior 
malocclusion,  where  some  doubt  would  or- 
dinarily exist  as  to  the  wisdom  of  extraction  as 
against  translation  of  several  teeth  or  expansion 
of  the  arch,  the  fact  of  extensive  caries  and 
exposure  of  the  pulp  of  one  or  more  molars  should 
weigh  heavily  in  favour  of  the  former  course. 
Unfortunately  it  often  happens  that  the  molars 
are  carious  in  the  jaw  in  which  it  is  very  desirable 
to  preserve  them,  and  sound  in  the  jaw  from 
which  their  removal  would  be  advantageous. 
Most  authorities  are  discreetly  reticent  on  this 
point,  and  the  fact  is  that  treatment  must  be 
unsatisfactory  whatever  course  is  adopted. 

In  cases  where  extraction  would  not  ordinarily 
be  practised,  but  one  or  two  molars  in  one  jaw 
must  be  sacrificed  on  account  of  extreme  caries, 
the  question  arises  whether  the  corresponding 
tooth  or  teeth  in  the  opposite  jaw  should  be 
removed.  The  answer  depends  largely  upon 
the  age  of  the  jiatient.  After  the  eruption  of  the 
second  molars  it  is  usually  best  to  sacrifice 
the  opposing  sound  tooth  of  a  condemned  first 
permanent  molar,  but  before  the  age  of  about 
eleven  this  course  is  not  necessary,  because  the 
second  molars  wiU  so  far  move  forward  during 
eruption  as  to  take  the  place  of  the  extracted 
tooth  with  little  or  no  tilting.  Cases  may  be 
seen  in  which,  after  early  extraction  of  a  single 
first  permanent  molar,  the  second  and  third 
molars  have  come  forward  and  little  or  no 
malocclusion  of  any  of  the  teeth  exists. 

The  problem  also  arises  as  to  the  wisdom  of 
extracting  two  sound  molars  on  one  side  of  the 
mouth  when  the  two  molars  on  the  other  side 


149 


must  of  necessity  be  removed,  iii  order  to 
prevent  deviation  of  the  centre.  It  may  happen 
that  some  deviation  or  other  abnormality 
already  exists,  and  wlien  tlie  deviation  is  towards 
the  affected  side  symmetrical  extraction  is 
usually  best.  Where  the  deviation  is  away 
from  the  affected  side  symmetrical  extraction 
is  not  usually  necessary  or  desirable.  Wlien  no 
deviation  exists  the  solution  depends  some- 
\\hat  upon  the  age  of  the  patient.  After  about 
thiiteen  years  of  age  the  second  and  third 
molars,  upper  and  lo\\er,  show  less  tendency 
to  move  forward  rapidly  without  tilthig  and  so 
abolish  the  space,  and  some  de^iation  of  the 
centre  is  likely  to  take  place.  The  problem 
then  consists  in  moving  these  molars  forward 
artificially,  or  deciding  whether  deviation  of 
the  centre  or  loss  of  two  sound  molars  is  the 
lesser  evil.  In  j'ounger  patients  deviation  can 
and  should  be  jorevented  by  artificial  means 
A\  hile  the  second  molars  are  moving  forward. 
It  will  sometimes  happen  that  when  two  molars 
must  be  removed  on  one  side  some  slight 
malposition  of  canines  or  premolars  on  the  other 
side  may  justify  the  removal  of  two  premolars. 
Such  a  course  of  treatment  may  be  good  policy 
and  result  in  a  perfectly  satisfactory  occlusion. 

It  should  never  be  forgotten  that  the  first 
permanent  molars  are  by  far  the  most  useful 
masticating  teeth  m  the  mouth,  and  the  most 
important  teeth  in  maintaining  the  full  size 
and  tnie  form  of  the  arch,  and  that  they  should 
always  be  preserved  unless  definite  indications 
for  their  removal  exist.  Theii-  so-called  tend- 
ency to  caries  is  mainly  the  result  of  infection 
from  carious  deciduous  teeth. 

It  has  been  said  in  previous  chajjters  that 
extraction  of  one  or  more  premolars  may  be 
necessary,  and  in  the  interests  of  occlusion,  when 
the  extraction  is  from  one  jaw  only,  the  first 
premolar  should  be  chosen.  Caries  of  the 
premolars  to  any  serious  extent  is  uncommon  at 
the  age  at  which  treatment  of  abnormalities  is 
undertaken,  but  a  considerable  degree  of  caries 
of  a  second  premolar  would  indicate  its  extrac- 
tion in  preference  to  the  loss  of  a  sound  first 
premolar,  followed  by  the  correction  of  occlusion 
by  artificial  means. 

When  four  premolars  are  to  be  removed,  or 
two  on  one  side,  the  choice  between  first  and 
second  depends  somewhat  upon  the  amount 
of  space  required.  WHien  this  is  small  the  second 
should  be  selected,  as  the  first  premolar  can 
easily  be  moved  back  and  any  excess  of  space 
will  be  remedied  by  forward  movement  of 
molars ;  otherwise  extraction  of  the  first  is 
more  useful  for  the  correction  of  misplaced 
canines. 

It  is  clear  that  the  decision  as  to  the  proper 
course  of  treatment  for  abnormalities  of  position 
is  complicated  and  rendered  more  difficult  by 


the  co-existence  of  caries,  and  each  case  must 
be  judged  on  its  ow n  merits ;  the  writer  hopes, 
however,  that  the  principles  laid  down  may  be 
of  assistance  to  the  student. 

Age  for  Mechanical  Treatment. — As  a  general 
rule  misplaced  teeth  should  be  reduced  as  soon 
as  it  is  obvious  that  without  treatment  they 
will  remain  in  a  false  position.  It  should  be 
remembered,  however,  that  slight  deviations 
are  often  corrected  by  natural  forces ;  this  is 
particularly  so  in  the  case  of  lower  incisors,  or  of 
premolars  which  have  been  deflected  by  a 
deciduous  root.  If,  however,  the  necessary 
space  for  a  misplaced  tooth  has  been  encroached 
upon,  there  is  little  or  no  likelihood  of  reduction 
[  by  natural  means.  Early  treatment  is  then 
desirable,  because  the  misplacement  must 
affect  the  positions  of  several  other  teeth. 
Many  of  the  most  complicated  cases  are  really 
but  the  outcome  of  simple  defects  at  an  earlier 
age,  and  prompt  treatment  has  the  great  advan- 
;  tage  of  bemg  largely  preventive.  It  may 
reasonably  be  thought  that  young  chUdron  are 
not  good  subjects  for  any  complicated  procedure, 
but  fortunately  in  then-  case  such  is  seldom 
required ;  the  defect  is  usually  inconsiderable 
and  the  treatment  simple.  Another  advantage 
of  early  treatment  is  that  the  bone  is  soft  and 
the  teeth  are  easily  moved ;  and  in  the  case  of 
teeth  with  incomplete  roots  there  is  none  of 
the  risk  of  death  of  the  pidp  that  sometimes, 
but  rarely,  occurs  with  older  children  when  the 
teeth  are  too  rapidly  moved. 

Malpositions  of  individual  deciduous  teeth 
are  not  very  common,  but  malocclusion  of  the 
arches  (usually  a  post-normal  jjosition  of  the 
lower  teeth)  is  frequently  seen ;  any  defect 
tha,t  can  be  corrected  fairly  easily  should  have 
attention  even  before  six  years  of  age,  because 
malposition  of  deciduous  teeth  is  inevitably 
followed  by  malposition  of  permanent  teeth. 
(This  especially  applies  to  narrowness  of  the 
arch,  which  certainly  involves  the  premolars 
later  on,  but  which  can  be  fairly  easily  corrected 
in  quite  young  children.) 

There  are  probably  but  few  cases  in  which 
treatment  as  soon  as  the  condition  has  plainlj"^ 
declared  itself  is  not  desirable,  but  in  some 
examples  associated  with  defective  bony  develop- 
ment an  expectant  attitude  is  occasionally 
admissible.  There  can  be  but  little  doubt  that 
the  development  of  the  jaws  proceeds  sometimes 
in  steps  or  stages  associated  with  varying  con- 
ditions of  general  health  and  nutrition,  rather 
than  continuously ;  and  under  these  circum- 
stances the  bony  development  may  not  pro- 
ceed pari  passu  with  dental  eruption.  It  is, 
therefore,  not  always  possible  for  the  most 
experienced  jiractitioner  to  pi-ophesy  whether 
some  slight  abnormality  may  not  become 
corrected  without  mechanical  interference  ;  but 


150 


casts  taken  at  regular  and  fairly  frequent 
intervals  will  be  of  great  assistance  in  estimating 
probabilities. 

Expansion  of  the  arcli  and  restoration  of  the 
anterior  teeth  to  the  positions  that  they  would 
presumably  have  occupied  if  osseous  develop- 
ment had  proceeded  on  normal  lines  no  doubt 
affords  considerable  stinuilus  to  the  growth  of 
bone;  but,  m  the  opinion  of  the  writer,  the 
presence  of  teeth  is  only  one  factor  m  stimulating 
development,  and  where  other  factors  are  want- 
ing or  insufficient,  it  is  not  wise  to  rely  on 
Nature  doing  the  rest  after  mere  tooth  move- 
ment by  mechanical  means.  Nevertheless,  it 
should  be  remembered  that  the  development  of 
surrounding  parts — the  nasal  cavities  and  the 
facial  muscles — follows  to  a  large  extent  on  the 
•eruption  and  position  of  the  teeth.  As  age 
advances  any  error  of  position  or  occlusion  of 
teeth  becomes  more  fixed,  not  only  by  reason 
of  the  deposition  of  bone,  but  also  because  of 
the  muscular  adaptation  of  the  soft  parts  : 
treatment  becomes  more  complex  and  retention 
more  uncertain. 

Difficulty  will  sometimes  occur  in  deciding 
between  extraction  of  premolars,  erupted  or 
unerupted,  and  other  treatment ;  that  is  to  say, 
in  deciding  whether  a  given  case  is  really  one  in 
which  such  treatment  is  permissible,  or  whether 
subsequent  development  will  render  it  un- 
desirable. When  such  doubt  exists  the  balance 
of  judgement  should  incline  to  the  more  con- 
servative treatment ;  at  least  no  harm  can  result 
beyond  making  the  case  rather  more  complicated 
later  on,  whereas  untimely  extraction  may  be 
regrettable. 

Principles  of  Retention.^ — It  is  obvious  that  it 
is  futile  to  attempt  the  reduction  of  any  abnor- 
mality unless  there  is  a  reasonable  prospect  of 
the  improved  condition  being  permanent  (44). 
This  stability  of  result  depends  upon  several 
circumstances.  The  first  essential  is  that  the 
cause  of  the  deformity  should  be  understood, 
and  the  measure  of  the  deviation  from  the 
normal  calculated  as  regards  the  position  of 
individual  teeth,  the  form  of  the  arches,  the 
occlusion,  and  the  form  and  development  of 
the  jaws.  Defects  of  a  plainly  hereditary 
character  are  not  only  difficult  to  remedy,  but 
tend  to  revert  with  great  persistency  after 
successful  treatment.  Deformities  involving 
bony  maldevelopment  give  less  prospect  of 
easy  retention  than  merely  misplaced  teeth, 
owing  to  the  fact  that  complete  cure  is  im- 
possible without  the  assistance  of  natural,  or 
at  any  rate  artificially  stimulated,  growth. 
This  is  the  case  even  where  the  prime  cause, 
such  as  adenoids,  has  been  removed,  but  much 
more  is  it  true  when  the  cause  of  evil  remains. 
It  has  been  pointed  out  that  in  a  normal  state 
the  teeth  are  kept  in  position  by  the  balance  of 


opposing  forces — the  cheeks,  lips,  tongue,  and 
muscles  of  mastication — -and  that  the  inter-digi- 
tation  of  cusps  in  normal  occlusion  greatly  helps 
to  fix  them  in  permanent  relationship  to 
adjacent  and  opposing  teeth.  It  is  not  always 
possible  to  ensure  a  normal  balance  of  forces 
acting  on  the  teeth,  but  an  approximately 
normal  occlusion  must  be  regarded  as  a  necessity. 
This  does  not  mean  that  a  perfectly  normal  oc- 
clusion with  all  the  teeth  present  is  a  sine  qua  non ; 
it  may  be  possible  to  achiev^e  a  stable  occlusion 
or  inter-digitation  of  cusps  after  extraction  of  two 
or  four  teeth,  and  the  result  may  be  more  easy  to 
retam  than  a  normal  occlusion,  with  the  roots 
out  of  position,  in  a  mouth  in  which  bony 
development  never  has  and  never  wiU  approach 
a  normal  state.  It  is  in  these  latter  cases  that 
the  balance  of  forces  often  fails  to  mature. 
It  should  be  said,  however,  that  where  extraction 
has  been  wrongly  practised  and  the  arch  unduly 
reduced,  results  must  always  be  unsatisfactory. 

Generally  speakmg,  difficulty  of  retention 
varies  with  difficulty  of  treatment,  but  this  is 
not  always  the  case,  because  in  weU-developed 
jaws,  complicated  tooth-movements  successfully 
achieved,  and  resulting  in  well-formed  arches 
and  good  occlusion,  may  need  very  little  sub- 
sequent care.  In  some  respects  teeth  moved 
through  small  distances  tend  to  revert,  because 
absorption  has  not  allowed  of  a  completely  new 
position  being  adopted.  Teeth  moved  quickly 
are  more  likely  to  revert  than  those  moved 
slowly.  In  any  case,  the  teeth  must  be  firmly 
retained  until  all  unequal  stress  has  become 
abolished  by  absorption,  and  until  deposit  of 
bone  has  fixed  them  in  their  new  positions. 
Such  processes  are  more  active  in  young  patients, 
and  consequently  retention  is  easier. 

Apparatus  for  retention  may  be  fixed  or 
removable.  The  former  is  usually  to  be  pre- 
ferred on  account  of  simplicity,  but  it  is  essential 
that  a  fixed  appliance  should  not  damage  the 
teeth  or  irritate  the  gums.  It  should  be  firmly 
fixed  with  cement,  and  no  extensions  or  rests 
upon  adjoining  teeth,  such  as  would  afford 
lodgement  for  food  particles  and  soon  cause 
caries,  should  be  permitted.  Li  some  cases — for 
instance  after  expansion  of  the  upper  arch — 
removable  apparatus,  if  kept  quite  clean  and 
used  constantly,  may  be  the  best.  Detailed 
description  of  retention  apparatus  and  its  use 
wiU  be  found  in  Chapter  X,  p.  227. 

Part  VII 

Mechanics  and  Physiology  of  Tooth  Movement 

Movement  of  a  tooth  is  brought  about  by 
the  application  of  one  or  more  forces.  Any 
small  movement  may  be  conveniently  repre- 
sented by  one  of  the  six  following  simple  move- 


151 


ments,   or  may   be  a   combination  of  two  or 
more  of  them — 

(1)  A  translational  movement  in  the  direction 

of  the  axis  of  the  tooth,  produced  by  a 
force  acting  along  tiie  line  of  the  axis 
in  either  direction.  The  tooth  is  either 
extruded  shghtly  from  its  socket  or 
pressed  into  it. 

(2)  A  translational  movement  along  the  line 

of  the  arch,  moving  the  tootli  towards 
one  neighbour  and  away  from  the  other. 
The  force  necessary  for  this  would  be 
perpendicular  to  the  axis  of  the  tooth 
and  would  meet  it  at  some  point  be- 
tween the  neck  and  apex  of  the  root. 
{3)  A  translational  movement  perpendicular 
to  the  line  of  the  arch  taking  the  tooth 
in  a  buccal  or  Imgual  direction.  Such 
a  force  cannot,  of  course,  be  imme- 
diately applied,  but  the  same  effect 
can  be  produced  by  the  application  of 
force  to  an  extension  from  the  crown  of 
the  tooth. 

(4)  A  movement  of  rotation  about  the  axis 

of  the  tooth.  For  this  a  couple,  or 
any  system  of  forces  equivalent  to  a 
couple,  is  necessary  in  a  plane  per- 
pendicular to  the  axis.  Two  parallel 
equal  and  opposite  forces  supply  the 
couple,  and  the  sole  measure  of-  the 
effect  of  a  couple  is  its  moment,  i.  e. 
the  product  of  either  force  and  the 
interval  between  them.  The  plane  of 
the  couple  does  not  make  any  difference 
in  its  effect,  so  long  as  any  altered  plane 
is  parallel  to  the  old  one. 

(5)  A  movement  of  rotation  produced  by  a 

couple  actuig  in  a  plane  perpendicular 
to  the  line  of  the  arch.  The  crown  and 
root  would  move  in  opposite  directions. 
A  certam  point  between  the  neck  and 
apex  would  remam  stationary. 
{6)  A  movement  of  rotation  produced  by  a 
couple  acting  in  a  plane  perpendicular 
to  the  buccal  and  lingual  direction,  i.e. 
perpendicular  to  the  force  in  (3).  The 
crown  moves  towards  one  neighbour 
and  the  apex  towards  the  other,  a 
central  point  remaming  stationary. 

It  so  happens  that  by  reason  of  the  invest- 
ment of  part  of  the  tooth  m  bone  and  gum 
these  simple  movements  are  rarely,  if  ever,  pro- 
duced, because  it  is  difficult  to  apply  the  corre- 
sponding forces ;  and  that  in  some  of  the  simple 
and  obvious  ways  of  applying  a  single  force 
a  compound  effect  is  produced.  For  example, 
suppose  a  force  applied  opposite  the  central 
point  of  the  crown  in  the  direction  of  the  line 
of  the  arch  (see  Fig.  247.)    Call  it  P.    Imagine  a 


parallel  and  equal  force  P'  acting  through  the 
point  A,  and  an  equal  and  opposite  force  P"  also 
actmg  through  A.  Then  P  and  P"  form  a  couple 
which  will  produce  the  effect  described  under 
(6),  and  the  force  P'  produces  the  effect  (2). 
The  combined  movement  of  (2)  and  (6)  gives  a 
rnovement  consisting  of  a  rotation  like  (6)  in 
kind,  but  with  a  centre  of  rotation  nearer  the 
apex  of  the  root  than  A.  Again,  suppose  a  thread 
wound  round  the  crown  and  pulled  tangentially 
in  the  direction  of  the  line  of  the  arch. 
Equal  additional  forces  imagmed  to  be  applied 
at  the  centre  of  the  crown  give  such  a  couple 
as  in  (4),  together  with  a  force  through  the  centre 
of  the  crown.  Hence  this  case  leads  to  a  com- 
bmation  of  the  movement  just  described  with 
an  axial  rotation. 

The  force  necessary  to  produce  the  various 
kinds  of  movement  may  be  smgle  or  multiple. 
The  specification  of  a  single  force  is  complete 


Fig.  247. 

when  the  magnitude  and  Une  of  action  are  given. 
If  the  lines  of  action  of  two  forces  intersect  in 
a  point  they  will  have  a  single  resultant 
force  acting  through  that  pomt ;  and  similarly 
several  forces  in  the  same  plane  are,  in  general, 
equivalent  to  a  single  resultant  force.  Whether 
the  forces  are  applied  by  means  of  push-screws  or 
traction-screws,  or  through  the  medium  of  steel 
springs,  rubber,  etc.,  does  not  affect  the  truth  of 
the  principle.  Two  wires  forming  a  long  V  (see 
Fig.  248)  and  actuig  on  a  tooth  T  with  a  push 
and  pull  (supposed  to  be  approximately  equal) 
have  the  effect  of  a  single  force  parallel  to  the 
base  of  the  V  (the  line  of  the  axis  of  the  tooth) 
and  acting  through  the  vertex  of  the  V.  The  wire 
V  may  be  regarded  as  a  rigid  extension  of  the 
tooth,  with  a  force  P  applied  at  the  extremity, 
the  apex  of  the  V.  Imaguiing  two  other 
parallel  equal  forces  along  the  axis  of  the  tooth, 
one  P'  in  the  same  direction  as  the  applied  force, 
and  the  other  P"  opposite,  the  force  P  is  seen 
to  be  equivalent  to  the  axial  force  P'  together 
with  a  couple  given  by  the  forces  P  P".  The 
moment  of  the  couple  is  the  product  of  the 
force    P    and   the  distance  T  T"  between  the 


152 


teeth.  It  follows,  therefore,  that  a  value  as 
large  as  possible  for  T  T'  secures  a  large  rotation 
movement  without  producing  much  extrusion 
or  intnision  of  the  teeth  T  T'.  The  rotation 
effect  is  modified  by  an  admixture  of   (1),  and 


T' 


Fig.  248. 

the'tooth  T  is  to  some  extent  extruded  from  its 
socket.  For  the  so-called  anchor  tooth  T'  the  force 
acting  is  the  exact  opposite  of  the  single  force 
P  at  the  apex  of  tlie  V,  and  presses  the  tooth 
into  its  socket.  Further  consideration  of  the 
principle  mvolved  in  this  method  will  be  found 
later  in  connection  with  the  contouring  apparatus 
of  Case. 

It  has  been  shown  that  the  application  of  a 
suigle  force  to  the  crown  of  a  tooth  perpendicular 
to  its  axis  really  results  in  a  compound  move- 
ment, because  the  resistance  is  provided  by 
the  bone  around  the  whole  root.  It  is  impossible 
to  say  exactly  at  what  point  the  resistance  is 
greatest,  but  the  farther  from  the  root  the  force 
is  applied  the  greater  will  be  the  amount  of 
rotation  in  relation  to  translation,  and  the  more 
rapid  will  be  the  movement.  If  force  be  applied 
at  the  pouit  of  the  crown  of  a  canine  tooth 
perpendicular  to  the  axis  of  the  tooth,  the 
centre  of  rotation  is  not  far  removed  from  the 
apex  of  the  root,  \\hich  probably  moves  to  a 
slight  extent  in  a  direction  opposite  to  that  of 
the  force  (see  Fig.  249).  A  movement  of  pure 
translation  cannot  be  produced  by  the  applica- 
tion of  force  to  any  part  of  the  crown  of  the 
tooth,  but  the  effect  can  be  produced  by  the 
application  of  force  to  an  extension  rigidly 
fixed  to  the  crowTa  and  overlying  the  root 
(see  Fig.  250).  It  is  the  line  of  action  of 
the  force  that  determines  the  kind  of  move- 
ment. In  actual  practice  such  a  movement  of 
pure  translation  would  be  difficult  to  obtain  by 
the  action  of  a  single  force,  because  of  the 
physiological  factors  presently  to  be  discussed. 
It  has  been  explained  that  rotation  of  a  tooth 


about  its  longitudmal  axis  can  only  be  obtained 

by  the  application  of  two  equal  and  opposite 

parallel    forces    constituting    a    couple,    or    by 

the    application    of    stresses    equivalent    to    a 

couple.     If  a  tangential  force  be  applied  to  one 

side  of  a  tooth,  and  the  opposite  side  be 

prevented    from    moving    in    the    same 

direction,  then  rotation  takes  place  around 

that  point  as  centre. 

Accordmg  to  the  means  by  which  force 
is  applied,  movement  of  a  tooth  may  be 
continuous  or  discontinuous.  In  discuss- 
ing the  effect  of  the  application  of  force, 
the  question  of  the  character  of  the  resist- 
ance encountered  has  not  been  considered, 
and  it  is  here  that  physiological  as  well  as 

T     physical  factors  have  to   be  recognized. 
If  the  root  of  a  tooth  were  embedded  in  a 
homogeneous  and  slightly  yielding  sub- 
stance, like  a  very  stiff  jelly,  the  immedi- 
ate small  amount  of  movement  would  be 
proportional  to  the  force,  and  continuous 
application  would  achieve  the  best  results. 
The  tooth  is,  however,  surrounded  by  an 
elastic   membrane    which    is    encased    in 
bone.    This  bone  is  unyielding,  at  least  as  regards 
the  physical  effects  of  any  force  employed  for 
purposes  of   tooth    movement.     The    effect    of 


Fig.  249. 

pressure  on  bone  is,  however,  to  produce  absorp- 
tion and  thereby  allow  of  movement  of  the 
tooth.  If  pressure  is  contmuous  the  periodontal 
membrane  is  in  a  constant  state 
of  compression  on  one  side  of  the 
tooth  and  tension  on  the  other, 
and  movement  proceeds  continu- 
ously as  absorption  permits. 

Roughly  speaking,  the  greater 
the  force  employed  (within  cer- 
tain limits),  the  more  rapid  is 
the  movement,  but  rapid  move- 
ment is  not  to  be  desked,  because 
too  much  force  produces  not 
simply  a  quiet  absorption,  but 
an  active  inflammatory  reaction 
of  the  periodontal  membrane  and  bone,  and 
endangers  the  vitality  of  the  pulp.  J.  P.  Buckley 
(.39)  has  collected  data  from  different  opera- 
tors and   published  some  interesting  statistics 


Fig.  2.50. 


153 


concerning  the  death  of  the  pulp  as  a  result  of 
tooth  movement.  It  appears  that  tlie  upper 
central  meisor  is  most  frequently  affected, 
possibly  because  it  is  most  often  misplaced 
or  moved  through  large  distances.  In  the 
discussion  on  Buckley's  paper  the  opinion  was 
generally  expressed  that  death  of  the  pulp 
was  due  to  rapid  movement  or  pressure  incon- 
stantly maintamed,  so  that  the  tooth  could 
osciUate.  The  pulp  of  a  tooth  in  which  the 
apex  is  fully  formed  is  of  course  more  likely  to 
be  strangulated  than  one  where  there  is  an 
open  apex. 

The  application  of  discontinuous  force  is 
probably  the  best  and  safest,  and  is  usually 
obtained  by  means  of  screws,  or  wire  bow 
and  ligatures,  as  will  presently  be  seen.  In 
this  way  the  chances  of  inflammatory  reaction 
are  reduced  to  a  minunum,  even  if  the  force 
used  is  excessive,  because  a  small  amount 
of  absorption  and  movement  relieves  the 
pressure  and  the  periodontal  membrane  gets 
periods  of  physiological  reaction,  instead  of 
being  kept  constantly  in  a  compressed  and 
anaemic  condition  on  the  whole  or  part  of  one 
side  of  the  tooth,  and  a  stretched  condition  on 
the  other.  In  fact  the  method  takes  advantage 
of  the  compressibility  of  the  periodontal  mem- 
brane. If  the  tooth  were  rigidly  embedded  in 
bone  the  application  of  discontinuous  force  by 
means  of  the  screw,  ligatures,  etc.,  would  be 
very  limited.  The  measure  of  the  rate  of 
movement  is  the  time  taken  by  a  sufficient 
amount  of  bone  to  become  absorbed  to  restore 
the  membrane  to  a  normal  condition. 

It  has  often  been  noticed  that  axial  rotation 
is  very  difficult  to  produce  and  that  tlie  tooth 
is  apt  to  get  very  loose  in  the  process.  There 
are  several  reasons  for  this.  If  the  root  is 
almost  a  pure  cone,  little  or  no  pressure  is 
brought  to  bear  upon  the  alveolus,  but  the 
periodontal  membrane  is  somewhat  violently 
stretched  at  every  point.  If,  on  the  other  hand, 
the  root,  as  often  haiDpens,  is  only  approxi- 
mately conical,  then  a  considerable  amount  of 
absorption  is  necessary  to  permit  of  any  move- 
ment, and  instead  of  this  taking  place,  ex- 
trusion is  liable  to  occur  to  allow  of  rotation 
without  absorption. 

It  is  stated  by  Guilford  (82,  p.  53)  and  others 
that  in  addition  to  absorption,  movement  is 
permitted  by  actual  bending  of  the  alveolus, 
especially  when  several  teeth  artificially  united 
are  moved  at  the  same  time,  or  in  phalanx 
as  it  is  sometimes  called.  TOiether  this  is  so 
has  not  been  definitely  proved,  although  it 
would  seem  that  in  cases  %^here  extensive 
movement  has  taken  place  absorption  and 
re-deposit  of  bone,  or  rather  fresh  deposit  of 
bone  in  a  new  place,  could  hardly  have  occurred  ; 
and  A.  H.  Ketcham  (98)  claims  to  have  demon- 


strated the  bending  of  bones  by  means  of  radio- 
graphs. But  it  is  difficult  to  understand  how 
bending  of  the  alveolar  plate  from  wliich  the 
teeth  are  being  separated  by  pressure  can  occur, 
and  the  explanation  offered  by  GuUford,  that 
it  is  effected  by  means  of  the  septa  of  bone 
attachmg  it  to  the  other  alveolar  plate,  does  not 
seem  quite  satisfactory.  F.  B.  Xoyes  (124) 
considers  that  the  nature  of  the  process  taking 
place  depends  upon  the  character  of  the  bone, 
and  that  in  moving  incisors  labiaUy  the  anterior 
alveolar  plate  is  carried  bodily  forward,  but 
that  in  moving  them  lingually  the  cancellous 
bone  is  more  readily  absorbed.  In  young 
subjects  formation  of  bone  takes  place  readily 
in  the  wake  of  a  moving  tooth  and  fills  up  the 
space  created.  Some  form  of  retention  appar- 
atus must  be  used  until  this  has  taken  place ; 
as  a  rule,  the  greater  the  movement  the  longer 
must  be  the  period  of  retention,  but  this  is 
also  affected  by  the  kind  of  movement  and  the 
character  of  the  deformity  corrected.  Treat- 
ment that  is  based  on  sound  principles  as  regards 
arch  conformation  and  occlusion,  and  is  de- 
vised to  assist  natural  forces  and  growth  rather 
than  antagonize  them,  need  rarely  be  followed 
by  a  very  prolonged  period  of  retention.  Re- 
version after  retention  for  a  reasonable  time  is 
a  pretty  certain  indication  that  treatment  was 
wrong  in  principle,  or  at  least  that  malposition 
of  teeth  was  but  one  sign  of  a  more  deep-seated 
deformity  ^^hich  has  held  its  groinid.  It  is 
not  certain  to  what  extent  absorption  and  re- 
deposit,  or  bending  of  bone,  takes  place  in  the 
case  of  maxillary  expansion,  and  whether  such 
change  is  limited  to  the  alveolar  portion ; 
Guilford  (82,  jj.  55)  suggests  that  separation 
of  the  median  suture  occurs,  followed  presum- 
ably by  fresh  deposit  (see  Fig.  251).  G.  V.  I. 
Brown  (37)  believes  that  with  the  kind  of 
apparatus  usually  used  for  expansion,  absorp- 
tion of  alveolus  only  occurs,  but  he  describes 
a  device  intended  to  produce  only  sej)aration 
of  the  median  maxillary  suture.  It  "  consists 
of  bands  attached  to  the  canines  and  molars 
on  each  side,  and  so  joined  that  when  a  bar 
with  screw  and  nut  is  attached  across  the  palate 
in  the  premolar  region,  the  force  applied  by 
turnmg  the  nut  will  cause  pressure  against  all 
of  the  teeth  upon  each  side  of  the  dental  arch." 
The  principle  consists  in  fixing  an  appliance  of 
which  force  is  resisted  by  all  the  posterior  teeth 
at  once,  so  that  the  union  at  the  suture  offers 
a  weaker  resistance.  G.  V.  I.  Bro\\n  states 
that  separation  of  the  central  incisors,  to  which 
nothing  is  attaclied.  occurs  after  a  short  period, 
thus  proving  separation  of  the  suture.  He 
regards  this  method  of  expansion  as  very 
valuable  in  increasing  the  width  of  the  inferior 
meatus  of  the  nose  in  cases  of  partial  or  com- 
plete   stenosis ;    measurements    are    given    to 


154 


prove  this  by  L.  W.  Dean  (67).  Some  remark- 
able results  by  Brown's  method  are  recorded 
by  F.  M.  Wihis  (172)  (see  Fig.  252).  A  similar 
method  called  Scliroeder's  is  advocated  by  Pfaff 
(128).  R.  Landsberger  (103)  (104)  describes  an 
appliance  compounded  of  a  helical  sprint:  and 


A  B 

Fig.  251. — Great  expansion  at  13  years  of  age.  A  :  diameter  of 
vault  in  molar  region,  1-60  in. ;  at  second  premolar,  1-33  in. ;  at 
first  premolar,  1'38  in. ;  at  canine,  1"25  in.  B  :  diameter  in  niolar 
region,  2-05  in.  (expansion  045  in.);  at  second  premolar,  187  in. 
(expansion  0-54  in.) ;  at  first  premolar,  1-68  in.  (expansion  0-30  in.) ; 
at  canine,  1'54  in.  (expansion  0'29  in.).  Case  treated  by  Lloyd  S. 
Lourie.     (Frbderick  C.  Kbmple  :]  Dental  Cosmos.) 

jack-screw  for  expansion  of  the  arch.  He  also 
gives  an  example  of  separation  of  the  central 
incisors  caused  by  pressure  in  the  premolar 
region,  and  shows  by  radiographs  separation 
at  the  inter-maxiUary  suture  and  deposit  of 
new  tissue  (see  Fig. 
253.) 

Within  the  last 
year  or  two  much 
attention  has  been 
given  to  this  ques- 
tion of  artificial 
separation  of  the 
maxillary  suture, 
and  several  interest- 
ing articles  on  it 
have  been  written. 
Several  operators, 
notably  Hawley  (88), 
and  Ketcham"  (97), 
believe  that  separa- 
tion of  the  pre- 
maxillary    suture 

only  is  possible.  Hawley  gives  an  interesting 
account  of  the  history  of  attempts  to  separate 
the  maxillary  suture,  and  the  objections  that 
were  entertained.  He  has  himself  adopted  a 
divided  arch  with  lingual  spurs,  and  occasional 
use  of  a  jack-screw,  and  by  these  means  has 
obtained  wide  separation  of  the  central  incisors, 


although  radiographs  show  no  separation  be- 
tween the  maxillae.  He  considers  that  what 
takes  place  is  "  the  stretchmg  of  the  thin  plates 
of  the  palate  between  the  reinforced  portion 
along  the  suture  and  the  thick  alveolar  structure 
surrounding  the  teeth."  Federspiel  (73)  believes 
that  the  maxillae  can  be  separated 
if  the  attempt  is  made  early  enough ; 
\'arney  E.  Barnes  (21)  also  considers 
separation  possible,  but  the  excel- 
lent radiographs  that  he  has  pub- 
lished seem  to  show  separation  of 
the  pre-maxillary  suture  chiefly  or 
entirely.  Pullen  (134)  gives  a  good 
summary  of  different  methods  of 
separation  adopted  and  the  results 
produced;  and  Wright  (173)  de- 
scribes an  interestmg  appliance  for 
measuring  the  internal  width  of 
the  nose  between  the  walls  of  the 
maxillary  sinus. 

Anchorage. — So  far,  the  effects  of 
the  application  of  force  to  a  tooth 
and  various  means  of  applying  it 
have  been  considered  ;  but  according 
to  Newton's  third  law,  "  To  every 
action  there  is   an  equal  and  con- 
trary reaction  "  ;    and  the  various 
appliances   used  for   movmg   teeth 
are  all  designed   with  reference  to 
what  is  miscalled  "  anchorage  ".     A 
simple    example    of    reaction    is    found   m   the 
inclined  plane  previously  referred  to.     The  force 
of  occlusion  is  met  by  an  equal  reaction  from 
the  inclined  plane  having  vertical  and  horizontal 
components,  but  the  physiological  conditions  are 


Fig.  252. — Period  between  A  and  B,  three  weeks.     (F.  M.  Willis  :  Dental  Cosmos.) 

such  that  the  effect  of  the  force  is  spent  entirely 
on  the  occluding  teeth,  the  inclined  plane  of 
metal  or  vulcanite  being  immovable  ;  the  vertical 
component  drives  the  teeth  into  their  sockets 
and  the  horizontal  component  forces  them  back- 
wards. There  is  no  such  thing  as  anchorage  in 
the  proper  sense  of  the  w-ord.     In  the  anchoring 


155 


of  a  iship,  a  movable  thing  (the  ship)  is  made 
stationary  by  being  attached  to  a  fixed  thing 
(the  sea  bottom  or  the  anchor  embedded 
in  it).  On  the  other  hand,  a  tooth,  com- 
paratively   a    fixture,    is    to   be   moved   by    a 


Fig.  253.- 


A  B 

-R.  Landsbergeb  :  Ash's  Quarterly  {now  Ash's  Monthly). 


stress  due  to  its  attachment  to  another  tooth 
or  teeth  regarded  as  absolutely  fixed.  The 
stress  is  often  likely  to  move  both  teeth.  If 
it  is  desired  to  move  A,  then  B  is  called  the 
anchor,  but  it  often  belies  its  name.  The 
nearest  approach  to  anchorage  is  in  the  case 
of  occipital  attachment,  in  which  the  actual 
effects  are  limited  to  the  tooth  or  teeth  to 
which  force  is  applied,  the  occiput  serving  as  an 
immovable  resistance. 

Other  kinds  of  attachment  resolve  themselves 
into  two  classes,  of  which  the  objects  are  quite 
different.  In  the  one  class  the  force  of  reaction 
is  distributed  over  several  teeth,  which  may  or 
may  not  be  rigidly  united,  or  over  the  gums 
and  subjacent  bone  in  addition ;  in  the  other 
class  the  force  of  reaction  is  deliberately  utUized 

to  move  one  or  more 
other  teeth  in  a  direc- 
tion opposite  to  that 
of  the  tooth  whose 
movement  is  chiefly 
desired  —  so -called 
reciprocal  anchorage. 
In  any  case  the 
amount  of  move- 
ment depends  upon 
the  relative  degrees 
of  resistance  of  the 
teeth  to  whicli  force 
is  applied. 

It  is  generally  con- 
sidered that  the  im- 
plantation of  a  molar  tooth  affords  more  resist- 
ance than  that  of  a  smgle-rooted  tooth,  but  the 
difference  is  not  very  great.  The  resistance  of 
a  molar  to  tilthig  depends  upon  the  resistance 
of  the  alveolus  for  the  greater  part  of  the  length 


Fig.  L'54. 


of  the  root  that  is  being  forced  against  it.  The 
terminal  portion  of  the  root  is  forced  in  the 
opposite  direction,  and  the  other  root  (or  roots) 
provides  little  or  no  resistance.  Thus  (Fig.  254), 
if  a  single  force  in  the  plane  of  occlusion  and 
in  tlie  line  of  the  arch  be  applied  to 
the  crown  of  a  molar,  resistance  is 
afforded  mainly  by  the  alveolus  oppo- 
site the  superficial  portion  of  the  root, 
of  uncertain  deptli  (A).  The  apex  of 
the  root  is  forced  backwards  somew  hat 
in  the  direction  shown  by  the  arrow, 
and  the  effect  on  the  other  root  is 
largely  extrusive.  In  fact,  length  of 
root  is  more  important  for  resistance 
to  such  a  force  than  number  of  roots ; 
and  herein  lies  the  reason  why  canine 
teeth  present  so  much  difficulty  in 
treatment. 

Although  action  and  reaction  are 
equal,  the  effect  of  the  force  of  reaction 
on  the  anchorage  maybe  much  reduced 
or  even  rendered  negligible  by  distribut- 
ing the  force  over  several  teeth,  and  in  fact  the 
resistance  to  mtrusion  of  a  tooth  that  it  is 
desired  to  translate  or  rotate  may  be  utilized. 

Some  distribution  may  be  obtained  by  the 
mamier  in  which  the  force  is  conveyed.  For 
instance,  in  the  case  of  traction  on  a  canine 


11.   „K^--L=m,..i: 


Fio.  255. — -This  and  the  following  figures  (to  Fig.  265) 
are  diagrams  intended  to  show  the  application  of 
forces  rather  than  actual  apparatus,  altliough  this 
is  indicated  in  some  detail.  For  example,  in  Figs. 
255  and  25(3  the  attachment  to  the  canine  band 
should  be  a  tube  at  right  angles  to  the  axis  of  the 
tooth,  to  allow  of  rotation  of  the  tooth  about  its 
apex.  A  simple  ring  in  which  the  bent  rod  fits 
loosely  will  also  answer  the  purpose.  Again,  in 
Fig.  258,  the  central  nut  should  be  square;  and 
in  Fig.  2(50.  the  attachment  at  A  and  B  is  not 
shown. 

by^means  of  a  stiff  rod  passing  through  a  tube 
of  a  molar  attachment,  if  the  tube  is  made  long 
and  the  tube  fits  the  rod  closely,  then  any 
tilting  of  the  molar  must  cause  considerable 
depression  of  the  anterior  end  of  the  tube 
(see  Fig.  255).  In  this  way  although  the  canine 
is   pulled   backwards,   any  tendency   to   tilting 


156 


of  the  molar  is  resisted  by  the  pressure  of  the 
canine  into  its  socket.  The  tendency  to  tilting 
is  less  if  the  molar  tube  is  near  the  gum 
margin. 

In  a  similar  manner  the  intervening  teeth 
may  be  made  use  of  by  resting  the  molar  tube 
in  hooks  attached  to  the  premolars  (see 
Fig.  256). 

If  a  molar  is  thus  prevented  from  tilting, 
the  resistance  of  the  alveolus  against  intrusion 


Fig.  25(5. 

for  the  whole  depth  of  all  the  roots  Ls  made 
use  of. 

Greatly  increased  resistance  of  the  anchorage 
is  afforded  by  the  rigid  union  of  adjacent  teeth, 
because  any  tilting  involves  bodily  lifting  of 
the  posterior  tooth  from  its  socket,  and  to 
produce  this  more  force  would  be  necessary 
than  is  usually  made  use  of  in  achieving  desired 
movements  (see  Fig.  257). 


Fig.  257. 

In  other  cases  the  stability  of  the  so-called 
anchor  tooth  can  be  ensured  by  an  additional 
appliance  attached  to  a  number  of  teeth.  The 
buccal  bow  is  the  most  usual  example  of  this ; 
attachment  of  the  bow  to  a  number  of  teeth 
has  the  effect  of  distributing  the  reaction  when 
a  force  is  applied  from  a  single  anchor  tooth  or 
the  bow  itself. 

In  the  case  of  removable  apparatus  in  the 
form  of  metal  or  vulcanite  plates,  or  Jackson 
skeleton  plates,  presently  to  be  described, 
resistance    is    afforded    by    the    various    teeth 


against  which  the  plate  rests,  and  also  by  the 
gum  and  bone  over  which  it  lies. 

Reciprocal  Action. — Wlienever  possible  the 
appliance  should  be  so  fixed  that  the  force  of 
reaction  is  applied  to  a  tooth  (or  teeth)  that  also 
requires  to  be  moved.  This  reciprocal  action 
may  be  made  to  apply  to  two  or  more  teeth  in 
the  same  jaw,  or  to  teeth  in  opposing  jaws.     A 


Fig.  258. 

simple  example  of  the  former  consists  in  di-aw  ing 
together  two  separated  mcLsors  by  means  of 
bands  and  a  rubber  ligature.  Another  example 
is  a  double  jack-screw  applied  to  two  lingually 
placed  premolars  on  opposite  sides  of  the  mouth 
(see  Fig.  258). 

The    reciprocating    jack-screw    is    similar    in 
principle,  but  acts  on  tMO  adjoining  teeth  and  is 


Fig.  259. 

loosely  attached  to  a  distant  tooth  (see  Fig.  259) . 
There  is  a  thrust  on  one  of  the  adjoining  teeth 
and  traction  on  the  other.  The  attachment  to 
the  premolar  of  the  opposite  side  in  the  figure 
is  to  prevent  the  end  swinging  round.  There  is 
a  stress  on  the  premolar  in  the  direction  in- 
dicated by  the  arrow,  but,  as  has  been  explained 
in  coimection  with  the  general  principles,  if  the 
V  is  long  the  stress  on  the  premolar  or  other 
attachment  is  very  slight. 


157 


The  contouring  apparatus  of  Case  (see  Fig. 
260)  is  an  example  of  reciprocating  action  in 
which  the  two  forces  are  applied  to  different 
parts  of  the  same  tooth  or  to  a  rigid  extension 
from  the  tooth.  As  has  already  been  explained, 
the  force  acting  on  the  end  of  the  rigid  extension 
A  B  has  the  same  effect  as  if  it  acted  on  the 
subjacent  root.  Case  states  that  if  the  forces 
producing  thrust  and  traction  are  equal  there 
is  no  effect  on  the  anchorage.  This  is  not 
correct ;  there  is  an  extruding  stress  on  the 
inolar  or  molars,  and  also  an  intruding  stress  on  the 
incisor.  If  the  direction  of  the  forces  on  the 
incisors  is  reversed,  there  is  an  intruding  stress 
on  the  molars  and  an  extruding  stress  on 
the  mcisors.  Obviously,  this  method  of  apjsli- 
cation  is  much  less  likely  to  produce  any  iU 
effects,  and  the  fact  should  be  remembered  in 
considering  the  advisability  of  adopting  either 
device. 

It  should  also  be  borne  in  mhid  that  the  longer 
the  V,  i.  e.  the  distance  bet-neen  the  tooth  to 
be  moved  and  the  anchor  tooth  or  teeth,  the 
less  wUl  be  the  effect  upon  the  molar.  The 
only  point  gained,  apart  from  mechanical 
convenience,  m  applying  one  force  to  an  exten- 
sion overlying  the  root  and  thereby  increasmg 
the  base  of  the  V,  is  that  a  smaller  force  is 
needed  to  produce  the  required  movement, 
the  effect  on  the  molar  being  the  same.  In 
making  use  of  this  apparatus,  however,  the 
object  may  be  to  move  the  root  a  great  deal 
and  the  incisal  edge  but  little  or  not  at  all ; 
and  in  that  case  one  nut  must  be  tightened 
much  more  often  than  the  other.     There  will 


A 


■nill  be  obliquely  forwards,  and  wUl  probably  be 
harmful.  Enough  has  been  said  to  show  "that 
a  blind  use  of  this  apparatus,  under  the  impres- 
sion that  its  only  result  is  a  simple  rotation 
of  the  mcisor  round  a  transverse  axis,  may 
cause  surprising  results,  and  that  a  .study  of 
the  mechanics  of  the  appliance  Ls  a  necessary 
preliminary  to  judicious  application. 

In  other  cases  the  action  may  not  be  so  simple 


B    \7 


Fig.  260. 


thus  be  a  passive  thrust  or  tension  in  the  rod 
not  interfered  with,  and  the  question  of  equality 
of  force  in  the  two  rods  depends  upon  the 
degree  of  resistance  of  the  two  teeth.  If  in 
the  figure  the  force  applied  at  A  be  greater 
than  the  force  applied  at  B,  then  the  direction 
of  the  force  of  reaction,  causing  extrusion  of 
the  anchorage,  will  be  obliquely  backwards,  the 
deflection  being  possibly  beneficial.  If,  on 
the  other  hand,  the  force  at  B  is  greater,  then 
the  force  producmg  extrusion  of  the  anchorage 


Fig.  201. 

and  direct,  but  be  conveyed  by  means  of  a 
third  tooth,  which  remains  more  or  less  station- 
arv  under  the  influence  of  two  opposmg  forces 
(see  Fig.  261). 

In  this  case  the  forward  puU  on  the  inolar 
produced  by  the  backward  force  applied  to 
the  canine  is  counteracted  by  the  thrust  on 
the  central,  but  a  certain  tendency  towards 
rotation  of  the  molar  exists.  This,  however, 
is  prevented  to  some  extetit,  if  the 
molar  tubes  are  made  fairly  long, 
by  the  fact  that  both  canine  and 
central  would  have  to  move  later- 
ally towards  the  median  line  of  the 
mouth  to  permit  of  it.  It  should 
be  luiderstood  that  such  an  inter- 
mediate anchor,  if  it  fulfils  any 
useful  purpose  in  suppljdng  any 
force,  must  itself  he  affected  by  force 
of  reaction  no  less  considerably,  and 
tliereby  be  displaced.  The  ordinary 
expansion  plate  with  Coffin  sjiring, 
or  with  right  and  left  screws,  or  a 
single  screw  and  sleeve,  and  the 
ordinary  expansion  bow,  are  examples  of 
reciprocal  action. 

Among  the  most  interesting  examples  of 
reciprocal  action  are  certain  methods  of  con- 
necting two  teeth  by  a  spring  in  such  a  way 
that  the  stress  on  each  tooth  shall  be  a  pure 
couple  (or  turning  movement).  The  ordinary 
expansion  bow  is  equally  flexible  throughout 
its  length,  and  the  chief  effect  of  its  action  when 
it  passes  through  tubes  attached  to  a  molar 
on  each  side  of  the  mouth  is  to  move  each  molar 


158 


in  a  buccal  direction.  If,  however,  the  end 
portions  of  the  arch  passing  through  the  tubes 
are  made  rigid  and  straight,  and  slide  freely 
in  the  tubes,  then  the  effect  on  the  molars  ^vill 
be  one  of  rotation  on  their  own  axes.     For  this 


Fig.  202. 

purpose  the  form  of  the  spring  bow  is  of  no 
consequence,  but  it  is  essential  that  the  molar 
tubes  should  not  be  parallel. 

This  consideration  is  of  importance  in  connec- 
tion with  the  action  of  a  spring  wire  in  moving 
two  misplaced  lateral  incisors.  If  the  terminal 
portion  of  the  wire  be  straight  and  stiff,  and 
slide  freely  in  the  tubes,  the  stress  on  the  laterals 
wiU  be  that  of  a  pure  couple,  and  the  effect 
rotation  (see  Fig.  262).  If,  on  the  other  hand,- 
the  spring  wire  be  straight  \vhen  unstressed  and 
flexible  throughout,  then  the  effect  of  the  action 
of  the  spring  wiU  be  to  rotate  as  before,  and 
in  addition  to  move  the  laterals  outivards  toicards 
the  canines  (see  Fig.  263).  This  is  contrary 
to  the  general    belief  that   the   effect   of   this 


Fig.   203. 

method  is  to  rotate  the  laterals  and  bring 
them  forward.  Rotation  there  may  be,  if  the 
ends  of  the  wire  are  stiff  enough,  but  fonvard 
translation  there  can  never  be. 

A  pure  couple  reaction  between  two  teeth 
may  be  secured  in  another  way  (see  Fig.  264). 
Suppose  two  rigid  rods,  straight  or  curved,  to 
be  connected  by  a  single  loop  of  spring  wire,  and 
two  other  loops  of  spring  wire  to  join  the  other 
ends  of  the  rods  rigidly  to  two  banded  teeth. 
Then  if  the  strength  of  all  the  springs  at  the  angle 
at  which  they  operate  is  equal,  and  they  all  tend 
to  open  or  to  close  the  angles  between  the  rods 
and  teeth,  a  movement  of  pure  rotation  wUl 
ensue  in  the  case  of  each  tooth.  The  same  effect 
win  be  produced  if  hinges  take  the  place  of  the 
springconnections.and  external  springs  of  rubber 
or  metal  be  used  to  open  or  close  the  angles, 
but  it  is  suggested  that  the  spring  connections 
will  prove  the  more  convenient  in  practice. 


In  a  modification  of  this  method  a  rod 
and  tube,  one  sliding  within  the  other,  can  be 
made  to  take  the  place  of  the  two  rods  con- 
nected by  a  sprmg  (see  Fig.  265).  Tliis  form 
may  be  more  convenient  on  occasion,  as  being 
less  likely  to  interfere  with  the  movements  of 
the  upper  lip. 

Examples  of  the  use  of  this  principle  have 
been  here  introduced  with  the  rotation  of  upper 
laterals  because  this  form  of  abnormality  is  per- 
haps the  commonest  example  in  which  double 
rotation  in  opjiosite  directions  is  required ;  but 
it  should  be  understood  that  the  principle  is 
applicable,  where  conditions  permit,  to  any 
abnormality  in  which  such  double  rotation  is 
necessary.  Furthermore,  if  pure  rotation  is 
necessary   for  one   tooth,   the   couple   reaction 


Fig.  264. 

may  be  obtained  from  a  distributed  anchorage 
of  two  or  more  teeth ;  in  tliis  case  the  anchor 
teeth  will  suffer  displacement  to  an  extent  that 
is  negligible.  It  should  be  understood  that 
these  methods  of  producing  the  effect  of  a 
couple  by  the  action  of  a  single  force  are  intro- 
duced as  being  meclianieaUy  sound,  but  not 
necessarily  as  being  practically  convenient.  In 
making  use  of  the  first,  the  writer  found  that 
the  necessity  of  frequent  adjustment  was  a 
source  of  difficulty. 

The  most  usual  examples  of  inter-maxiOary 
action  consist  of  the  elastic  attachment  to 
buccal  arches  in  each  jaw.  The  effect  on  the 
several  teeth  concerned  is  controlled  by  the 
mamier  in  \\hich  the  arches  are  attached  to 
the  teeth.     If  in  one  jaw  the  arch  is  attached 


Fig.  2(i5.i 

to  only  two  teeth,  and  in  the  other  jaw  tO' 
several,  the  effect  on  the  former  is  concentrated 
on  the  two  teeth,  and  in  the  latter  is  distributed 
over  several.  If  the  arches  are  firmly  attached 
to  several  teeth  in  both  jaws,  then  the  effective 
force  will   be  mainly  expended  on  the  lower 

'  The  loop  in  this  figure  would  be  better  arranged  as 
in  Fig.  264,  to  exert  force  when  openinq.  If  used  as 
shown,  spring  must  be  given  to  tlie  loops  so  as  to  exert 
force  when  closing. 


159 


jaw  as  a  whole,  and  may  be  used  in  this  way 
in  altering  the  occhision. 

This  principle  of  concentration  and  distribu- 
tion of  force  is  of  great  importance  in  all  forms 
of  reciprocal  action ;  examples  will  be  found  in 
the  discussion  of  the  details  of  treatment. 


Paet  VIII 

Preliminaries  of  Treatment,  and  Care  of  the  Mouth 
and  Appliances 

Preliminaries  of  Treatment. — Mention  has 
been  made  in  the  section  on  "  Diagnosis  "  of  the 
various  points  tliat  should  be  noted  concerning 
the  patient,  the  mouth,  and  the  teeth,  at  the 
first  sitting.  It  is,  however,  but  seldom  that  a 
decision  can  at  once  be  come  to  regardmg  the 
main  principles  of  treatment,  and  it  is  necessary, 
therefore,  to  obtain  impressions  of  both  arches 
in  order  to  make  casts  for  purposes  of  study, 
and  as  records,  quite  apart  from  the  manufac- 
ture of  apparatus.  For  the  latter  object  it  is 
often  desirable  to  take  separate  impressions. 
Casts  for  study  and  reference  should  also  be 
made  at  intervals  during  the  progress  of  the  case. 
Difference  of  opinion  exists  as  to  the  best  material 
with  which  to  take  impres- 
sions. Undoubtedly  the 
most  correct  impression  can 
be  obtained  with  plaster-of- 
Paris,  but  almost  equally 
good  ones  can  be  got  with 
composition.  The  choice 
may  to  some  extent  depend 
upon  whether  fixed  or  re- 
movable apjjaratus  is  to  be 
used.  The  fitting  of  bands, 
and  to  a  large  extent  the 
assemblmg  of  parts  should 
be  done  to  the  natural  teeth, 
and  the  cast  only  used  as  a 
general  guide ;  but  the  use 
of  plaster  is  largely  advocated  by  those  who 
strongly  favour  fixed  appliances,  and  this  is 
because  they  very  rightly  attach  great  import- 
ance to  reaUy  accurate  records  for  purposes  of 
study  and  comparison.  If  vulcanite  plates  are 
to  be  made  there  is  a  distinct  advantage  in 
plaster  impressions,  so  that  the  stability  of  the 
plate  may  be  as  far  as  possible  independent  of 
bands  or  wires,  but  with  proper  care  very  good 
impressions  can  be  taken  with  composition. 
The  essential  point  is  that  whatever  material 
is  used,  accurate  casts  must  be  obtained, 
whether  for  use  or  reference.  The  age  and 
temperament  of  the  patient  are  important 
factors ;  with  many  children  the  taking  of  a 
satisfactory  impression  in  composition  is  diificult 
enough,  and  to  take  one  in  plaster  would  be 
impossible.     Recent  developments  tend  towards 


treatment  being  undertaken  at  a  much  earlier 
age  than  was  formerly  the  case,  and  for  young 
children  composition  is  usually  the  best  material. 
Before  any  impression  is  taken,  tartar  if 
present  should  be  removed,  the  teeth  and  mouth 
cleansed  with  compressed  air  or  otherwise,  and 


Fig.  266. — ST,  Scribing  tool.  T,  Tripod  with  adjust- 
able rubber  pads.  (G.  Northcroft.)  {Messrs. 
Claudius  Ash,  Sons  &  Co.) 

washed  with  an  antiseptic.  The  taking  of  an 
impression  in  plaster  does  not  greatly  differ 
from  the  method  used  in  pro.sthetic  dentistry, 
and  need  not  be  described  m  detail.  The 
flanges  of  the  tray  should  be  deep  enough  to 
cover  the  gums  on  the  buccal  aspect,  the  tray 
should  be  just  large  enough  to  allow  of  about 


Fig.  267.— SB,  f^liooti 


ng  board.   P,  Plane.   (G.  Northcroft.)  (Messrs.  Claudius 
Ash,  Sons  S  Co.) 

J  uich  of  plaster  between  it  and  the  gums, 
and  the  posterior  edge  of  an  upper  tray  should 
be  turned  up  for  about  J  uich.    Excellent  trays 


Fig.    268. — Blade   sharpener   with   outline    of   plane. 
(G.NoRTHCRorr.)  (Messrs.Claudlus  .i.sh.Sons  dk  Co.) 

are  made  by  the  S.  S.  White  Manufacturing 
Company  to  the  design  of  E.  H.  Angle,  and, 
especially  for  very  yoimg  patients,  by  the 
Dental  Manufacturing  Company  to  the  design 


160 


of  E.  A.  Bogue.  After  removal  of  the  tray  j 
the  plaster  should  be  scored  opposite  the 
canines  to  facilitate  fracture  when  the  plaster  is 
hardened.  The  whole  process  is  \\-ell  described 
by  Alfred  P.  Rogers  (137)  and  by  H.  A.  Pullen 
(132).  For  impressions  in  composition  the 
tray  should  be  similar,  except  that  the  posterior 
edge  of  an  upper  tray  should  not  be  turned  up. 
The  chief  essential  is  that  the  composition  should 
be  of  the  correct  degree  of  softness  ^^•hen  in- 
serted, and  should  be  thoroughly  hard  before 
being  removed.  After  the  composition  has 
been  uiserted  in  the  tray  while  quite  soft,  the 
tray  should  be  cooled  with  cold  \\ater  so  as  in 
some  degree  to  harden  the  deeper  portion  of  the 
composition.  The  surface  should  then  be  care- 
fully softened  over  a  clean  flame  and  slightly 
vaselined.  For  removal  the  tray  should  be 
grasf)ed  very  firmly  with  the  thumb  close  to  the 
buccal  jjortion,  and  the  forefinger  opposite,  and 
the  other  fingers  inside  the  mouth,  and  the  back 
part  of  the  impression  should  be  tUted  from  the 
teeth.  After  slight  loosening  to  admit  saliva 
it  is  a  good  plan  to  press  the  composition  again 
firmly  into  place  and  leave  for  a  few  moments 
before  careful  removal. 

In  addition  to  impressions  of  the  upper  and 
lower  arches,  either  an  anterior  occlusal  impres- 
sion with  the  teeth  closed,  or  a  soft  wax  inter- 
occlusal  impression,  should  usually  be  taken  to 
ensure  correct  occlusion  of  the  casts  later.  The 
casts  should  be  trimmed  so  that  the  base  of  each 
is  parallel  to  the  plane  of  occlusion,  and  the  back 
and  sides  vertical  or  slightly  wider  at  the  base. 
For  this  purpose  a  sharp  knife  and  a  plaster 
plane  should  be  used.  It  is  desirable  to  trim 
all  models  on  a  uniform  plan,  and  to  differentiate 
between  upper  and  low  er  as  advised  by  Pullen. 

An  excellent  method  of  achieving  these 
results  has  been  devised  by  G.  Northcroft.  The 
apparatus  consists  of  a  nickel-plated  brass 
scribing  tool,  an  adjustable  rubber-padded 
tripod  on  which  to  rest  the  model  teeth  down- 
wards, a  shooting-board  with  an  adjustable 
angle-piece,  a  bronze  plane,  and  a  blade- 
sharpener  (see  Figs.  266,  267,  268). 

The  casts  should  have  stamped  car  the  front 
the  number  of  the  case  (together  with  a  letter 
indicatiag  the  order  of  the  series  in  the  case) ; 
on  the  back  the  date ;  and  on  the  base  the  age 
in  years  and  months.  They  should  be  kept  in 
a  cabinet,  or  back  to  back  in  cardboard  boxes, 
with  pieces  of  card  between  the  pairs.  A  con- 
venient size  for  the  box  in  inches  is  12  x  3  X  3. 

In  many,  if  not  most,  cases  of  major  abnor- 
malities photographs  of  the  patient  should  be 
taken.  The  most  useful  aspect  is  a  profile  view 
with  the  teeth  closed  and  the  lips  naturally 
disposed,  but  sometimes  a  full  face  view  is  also 
useful.  C.  S.  Case  makes  a  practice  of  taking 
facial  impressions,  and  has  obtained  excellent 


and  beautiful  results,  but  only  a  very  small 
proportion  of  British  patients  would  consent  to 
this  process,  and  if  they  would  it  is  very  doubtful 
whether  such  advantages  as  there  may  be  over 
photographs  are  sufficient  to  compensate  for  the 
extra  time  and  difficulty  to  the  operator  and 
discomfort  to  the  patient. 

A  loose-leaf  case-book  should  be  kept  and 
all  measurements  and  other  details  entered 
before  commencuig  treatment.  A  useful  form, 
adopted  by  Harold  Chapman  is  as  follows — ■ 


Name 

Date  of  Birth 

No.  of  Case 

Classification 

Pro3opometric  meas.  in  mm. 

Upper 

Lower 

Nasion 

Chin 

Upper  Alveolar 

Lower  Alveolar 

Tip  of  Upper  Central 

Tip  of  Lower  Central 

Lingual     Sulcus    of     1st 

Width  through  Ext.  Aud. 

Upper  Molar 

Jleati 

Width  of  Centrals 

Width  of  Laterals 

do         Arch  (before  treat- 
ment) 

Estimated  Width  of  Arch 
(Haniey) 

Method  of  Breathmg 

do.         Feeding 

do.        Sleeping 

Habits 

Surgical  operations 

Congenital  or  acqd.  diseases 

Family  characteristics 

Aesthetic  considerations 

Overbite 

Models 

Letter 


Date 


Date  of  first  visit 

Date  of  starting  treatment 

Date  of  first  retention 

Date  of  removal  of  final  retention 

Total  number  of  visits 


Details  of  treatment  and  the  progress  of  the 
case  should  be  recorded  on  plain  leaves  im- 
mediately following. 

Care  oi  the  Mouth  and  Appliances. — Whatever 
form  of  appliance  is  used,  the  patient  and  those 
responsible  for  him  should  be  instructed  in  the 
proper  care  of  the  mouth  and  the  arts  of  cleanli- 
ness. Removable  plates  should  be  thoroughly 
brushed  with  a  small  stiff  brush,  soap,  and 
powder,  at  least  twice  a  day,  and  then  disin- 
fected  in  an  antiseptic   solution.     A   suitable 


161 


mouth-wash  should  be  prescribed  (see  Chapter 
XVIII,  p.  332). 

The  operator  should  take  every  opportunity 
of  keeping  the  teeth  and  fixed  appliances  clean 
by  means  of  revolving  brushes  and  rubber  cups, 
with  a  fine  polishing  powder,  and  by  means  of 
compressed  air  with  suitable  medicaments. 

This  matter  is  dealt  with  very  thoroughly  by 
H.  C.  Ferris  (74).  For  use  by  the  operator  in 
the  form  of  a  spray  for  general  antiseptic  pur- 
poses he  recommends  tricresol  dissolved  in 
cinnamon  water  to  disguise  the  flavour.  It  is 
said  to  have  three  times  the  disinfectant  value 
of  carbolic  acid  and  to  be  three  times  less 
poisonous  and  less  caustic — 

R. 

Tricresol n\  xxx. 

Aquae  Cinnamomi     .        .        .    §  iv. 
M.    Sig. — To  be  used  in  spray  at  the  tempera- 
ture of  115°  F. 

As  a  stronger  antiseptic  m  case  of  acute  in-  1 
flammatory  conditions  he  recommends  iodine  in 
potassium  iodide,  followed  by  starch  to  combme 
witli  the  iodhie  and  render  the  mucoid  substances 
easUy  removable  as  a  flocculent  precipitate  by 
an  alkaline  wash. 

B. 
lodi 

Potassii  lodidi 

Aquae  DestUlatae        .        .        q.  s.  5  iv. 
M.   Sig. — To   be  used   in  spray   under   high 
pressure  at  the  temperature  of  98°  F. 

R. 

Amyli gr.  xxxviij. 

Aquae  Mentli.  Pip.       .        .  §  iv. 

01.  Menth.  Pip.    .        .        .  Ti\  xx. 

Mix  the  first  two  ingredients  and  let  stand  for 
five  minutes,  then  boil  for  five  minutes,  and  then 
add  the  flavouring. 

R. 

Sodii  Carb gr.  xxxviij. 

Aquae  Gaultheriae       .        .       3  iv. 
01.  Gaultheriae     .        .        .       Il\  xxx. 
M.  Sig.- — To  be  used  at  the  temperature  of 
115°  F. 

As  a  mouth-wash  for  use  by  the  patient  night 
and  morning,  or  oftener  if  necessary,  Ferris 
recommends  the  following — 

R. 

Hydronaphthol    .        .        .     ) 
Menthol 


>aa  n\  xix. 


\ 


Vaa  n\  iv. 


Olei  Gaultheriae 
Olei  Cassiae  . 
Sp.  Vin.  Rect. 
Tinct.  Capsici 
Aq.  Destillatam 

M.  ft.  collutorium.     Sig.- — One  teaspoonful  in 
lialf  a  glass  of  hot  water. 
6 


[Sia.  gr.  xxx. 


ad.  3 


The  question  of  iU  effects  produced  by  the  use 
in  the  mouth  of  noble  metals  and  German  silver 
has  been  carefully  investigated  by  Clarence  J. 
Grieves  (79)  (80).  He  finds  that  the  latter 
wastes  considerably  and  produces  a  profound 
modification  in  the  character  of  the  saliva,  to 
such  an  extent  as  probably  to  uihibit  the 
digestion  of  starches  by  ptyalin.  He  therefore 
recommends  that  noble  metals  oiJy  should  be 
used  in  the  mouth,  although  there  is  greater 
likelihood  of  enamel  decalcification,  which, 
however,  can  be  largely  prevented  by  prophy- 
lactic measures.  Grieves  discourages  the  use  of 
ligatures  without  cemented  bands,  and  such 
appliances  as  afford  lodgement  for  food  particles, 
and  speaks  of  tlie  advantages  of  removable 
appliances.  It  is  interesting  to  find  that  it  is 
possible  for  propliylaxis  to  be  too  perfect  and 
promote  caries  by,  as  he  considers,  removal  of 
mucus.  He  advocates  silver  nitrate  treatment 
for  coagulation  of  mucus. 


Part  IX 

Surgical  Treatment 

Before  describing   the   various  more  or  less 
complicated    appliances    by   which  teeth    may 
be  brought  into  correct  alignment  and  occlu- 
sion, it    will   be   well   to   describe  the  method 
of  surgical  treatment ;   its  application  is   very 
limited   m  scope,   but   within 
those  limits  "immediate  regu- 
lation ",  as  it  is  usually  called, 
is  distinctly  useful.     There  are 
two  methods  of  treatment,  of 
which    the    simpler    wfll     be 
first  described.     It  consists  in 
forcibly  reducing  a  tooth  to  its 
proper  position  by  means  of  a 
special  pair  of  forceps  designed 
by  Grevers,  of  which  one  blade 
resembles  those  of  an  ordinary 
pair  of  straight  forceps  and  the 
other  is  square  m  section  and 
has    fitted   to    it    a   T-piecc. 
consistmg  of  a  slightly  curved 
metal  plate  covered  with  thick 
rubber  tubing,  to  rest  on  tlie 
gums  above  the  roots  of  the 
tooth  to   be   moved   and    tlie 
adjacent  teeth  (see  Fig.  269). 
The  particular  form  of  abnor- 
mality to  which  the  treatment 
is  best  suited,  if  not  limited, 
is   lingually  placed  upper  in- 
cisors and  canines  occluding  lingually  with  the 
correspondmg  lower  teeth.     It  is  necessary  that 
the  normal  space  of  the  misplaced  tooth  should 
not  have  been  encroached  upon  to  any  serious 
extent,  although  it  is  not  necessary  that  the 


Fig.  269. — Grovers' 
forceps. 


162 


space  should  be  ample,  as  the  adjacent  teeth 
can  be  forcibly  separated  a  little  during  the 
operation.  Tlie  patient  should  preferably  be 
anaesthetized,  the  plain  blade  is  applied  to  the 
cuiguluni  of  the  tooth,  and  the  rubber-covered 
plate  to  the  gum  above  the  apex  on  the  labial 
aspect,  and  steady  forward  pressure  is  made. 
On  account  of  the  elasticity  of  the  alveolus  a 
considerable  amomit  of  movement  of  the  tooth 
takes  place  without  fracture  of  the  anterior 
plate  of  alveolus,  but  pressure  should  be  main- 
tained until  fracture  occurs  with  a  sudden  snap, 
and  the  tooth  forced  into  a  position  slightly  in 
advance  of  normal.  When  the  alignment  of 
the  lower  teeth  is  normal  no  further  treatment 
is  requu'ed,  as  the  occlusion  will  be  sufficient  for 
retention,  but  ui  some  cases  a  swaged  or  cast- 
metal  splmt,  or  bands,  should  be  cemented  to 
the  tooth  and  adjacent  teeth  as  soon  as  anj^ 
slight  bleeding  has  ceased.  8uch  a  splint  should 
of  course  have  been  made  beforehand  to  a 
corrected  model.  The  teeth  to  which  the 
method  is  particularly  adapted  are  upper  lateral 
incisors,  and  if  the  operation  is  performed  at  an 
age  before  the  complete  calcification  of  the  apex, 
no  doubts  need  be  entertauied  as  to  the  survival 
of  the  pulp.  In  fact,  it  may  be  done  with  toler- 
able safety  at  later  ages,  and  Sidney  Spokes 
(144),  who  has  had  considerable  experience  of  the 
method,  considers  that  there  is  no  risk  of  death 
of  the  puljj  after  calcification  of  the  apex.  The 
operation  is  hi  the  experience  of  the  wTiter  one 
that  can  be  carried  out  easily  and  successfully. 
The  more  elaborate  operation,  used  and 
described  by  Bryan  (38),  and  Cumiingham 
(62)  (63),  consists  in  dividing  both  plates  of 
alveolus  on  each  side  of  the  misplaced  tooth 
bet^^een  it  and  the  adjacent  teeth  by  means  of 
a  circular  saw,  and  then  forcibly  reducuig  the 
tooth,  together  with  the  portion  of  alveolus 
attached,  by  means  of  a  special  pair  of  forceps. 
A  vulcanite  plate  is  used  to  fit  over  the  jaw, 
teeth,  and  gums,  to  protect  the  parts  during 
the  operation  of  sawmg.  A  groove  is  cut  in 
this  plate  exposmg  the  tooth  to  be  moved,  and 
a  brace  of  steel  or  brass  is  embedded  in  the 
vulcanite  over  the  apex  of  the  root,  to  act  as  a 
supjiort  for  one  beak  of  the  forceps.  The  tooth 
can  be  retained  in  the  new  position  until  bony 
reunion  has  taken  place  by  means  of  silk  thread 
attached  to  it  and  its  neighbours.  There  is  thus 
no  separation  from  the  lingual  plate  as  m  the 
other  metliod,  but  as  this  alveolus  is  in  any  ca.se 
soon  re-formed  tliere  does  not  appear  to  be  any 
great  advantage  therehi.  Death  of  the  pulp 
frequently  ensues,  and  it  must  be  removed  before 
staining  occurs.  This  method  of  "  alveolotomy  " 
has  been  u.sed  by  W.  H.  Dolamore  (71),  who 
has  related  a  large  number  of  cases.  Instead 
of  a  circular  saw  he  used  in  some  instances  a 
modified  Hey's  saw,  or  a  special  fret-saw.     He 


employed  Bryan's  forceps,  and  retained  the 
tooth  m  its  new  position  by  means  of  a  metal 
cap  cemented  in  position  and  covermg  the 
adjacent  teeth.  Possibly  the  more  elaborate 
method  is  applicable  to  more  grossly  misplaced 
teeth  than  the  one  first  described,  but,  on  the 
other  hand,  it  is  at  least  doubtful  whether  in 
such  circumstances  gradual  methods  would  not 
be  preferable. 

N.  G.  B. 


(1) 

2 
3 

4 


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(79)  Grieves,  Clarence  J.     Base  Metal  versus  Noble 

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(83)  Hall,   E.    E.     Malocclusion   from   the   Dentist's 

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(85)  Hawley,    C.   a.     Determination   of   the   Normal 

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(92)  Heuckeroth,  F.      Open  Bite  in  a  Female  aged 

Fifteen.     Ash's  Quarterly,  Dec.  1892,  p.  281. 

(93)  Hopson,      Montagu       F.        Heredity.       Trans. 

B.S.S.O.,  November  1909.  Dental  Record, 
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(97)  Ketcham,  A.  H.      Treatment  by  the  Orthodontist 

Supplementing      that     by     the     Hhinologist. 
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(101)  KoRBTTZ,     Alfred.      The    Geometrical    Deter- 

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(109)  LouRiE,    Lloyd    S.     The   Necessity   for   Early 

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(110)  McBride,    R.    D.     Jimaping   the   Bite.     Dental 

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(111)  MoBbide,    R.    D.     Modern     Developments     in 

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(112)  McKenzie,    Dan.     The   Relation   of   Dentistry 

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(114)  Marfan.     Rickets  in  Relation  to  Arched  Palate 

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(115)  Mass.art,  Jean.     Evolution  by  Atrophy. 

(116)  Mendell,  GtfiLHERMENA  P.     Corrected  Case  of 

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(117)  Mendell,  Gotlhermena    P.     A  Corrected  Case 

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(118)  MosHER,  Harris  Peyton.     The  Influence  of  the 

Pre-maxillae  upon  the  Form  of  the  Hard 
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(119)  Nobthcroft,     G.     Orthodontia.        Brit.     Dent. 

Jour.,  1908,  Vol.  XXIX,  p.   11. 

(120)  Nobthcroft,     G.     Trans.     B.S.S.O.,     Jan.     to 

April  1908.  Dental  Record,  1908,  Vol.  XXVIII, 
p.  214. 

(121)  Northcroft,     G.       Lateral     Malocclusion     in 

Deciduous  Dentition.  Trans.  B.S.S.O.,  Dec. 
1909.     Dental  Record,  1910,  Vol.  XXX,  p.  105. 

(122)  Northcboft,   G.     A   Few   Observations  on   the 

Mouths  of  25  Children  from  Two  and  a  Quarter 
to  Six  and  a  Half  Years  of  Age.  Dental 
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Dental  Review). 


165 


An  Operation  on  the  Fraenum 
B.S.S.O.,  1912.    Dental  Record, 


(123)  NORTHCROFT,  G. 

Labii.     Trans. 
p.  874. 

(124)  NoYES,  Frederick  B.     A  Study  of  the  Peri- 

dental Membrane  from  the  Orthodontist's 
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dontists, 1903—4,  p.  144.  Items  of  Interest, 
1904,  p.   795. 

(125)  Ottolengui,    Rodrigues.     A    Contribution    to 

tlie  Knowledge  of  the  Aetiology  and  Treat- 
ment of  Cases  in  Class  II.  Trans.  Amer.  Soc. 
of  Orthodontists,  1907,  p.  85.  Items  of  Interest, 
1908,  p.  495.  Discussion,  p.  510. 
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Treatment  of  Malocclusion.  [J.  Lowe  Yoting 
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(127)  Pedley,   T.   F.     Rubber  Teat  and  Deformities 

of  the  Jaws.  Brit.  Dent.  Jour.,  1907,  Vol. 
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(128)  Pfaff,  W.     Stenosis  of  Nasal  Cavity — Abnormal 

Position  of  Teeth.  Dental  Cosmos,  1905, 
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(129)  PuKERiLL,    H.    P.     Double    Resection    of    the 

Mandible.  Dental  Cosmos,  Nov.  1912,  Vol. 
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(130)  Plumley,     A.     G.     Adenoids     in     Relation     to 

Mouth-breathing.  Brit.  Dent.  Jour.,  1906, 
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(131)  PoLLiTT,     G.     Paton.     Inferior     Protrusion     in 

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(132)  PuLLEN,  H.  A.     Johnson  s  Operative  Dentistry. 

(133)  PuLLEN,  H.  A.     Mouth-breathing.     Dental  Cos- 

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(134)  PuLLEN,  H.  A.     Expansion   of  the  Dental  Arch 

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to  the  Development  of  the  Internal  and 
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(135)  PuLLEN,  R.  N.     Early  Corrective  Treatment  of 

Malocclusion.     Items  of  Interest,  1909,  p.  908. 

(136)  Read,    Henry.     Facial    Expression    from    the 

Point  of  View  of  the  Artist.    Items  of  Interest, 

1911,  p.  328. 

(137)  Rogers,    Alfred     P.     Art     in     Model-making. 

Trans.  Amer.  Soc.  of  Orthodontists,  1905,  p.  79. 
Items  of  Interest,  1906,  p.  060. 

(138)  Rogers,  Alfred  P.     A  Consideration  of  Infra- 

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(140)  RusHTON,    William.     The    Effects    of    Mouth- 

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(141)  SIMMS,    W.     The   Eruption    of   the   Teeth     con- 

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(142)  Spicer,    Sc.\nes.     On    Nasal    Obstruction    and 

Mouth-1  reathing  as  Factors  in  the  Aetiology 
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(143)  Spiller,  J.  E.     A  Classification  of  Dento-facial 

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(144)  Spokes,    Sidney.     The    Forcible   Advancement 

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Dental  Cosmos,  1908,  Vol.  L,  p.  797. 


146) 


147) 


148) 


149) 
160) 


1.^1) 
152) 


153) 
154) 


155) 

156) 
157) 

158) 
159) 

160) 
161) 


162) 
103) 


164) 
165) 

166) 

167) 

168)"^' 

169) 
170) 

171) 
172) 


SuMMA,  Richard.  A  Few  Thoughts  Concern- 
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of  Interest,   1906,  p.  493. 

Talbot,  W.  O.  A  Case  of  Double  Resection 
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Aetiology  of  Face,  Nose  and  Jaw 
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p.  754. 
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Thomson,  J.  Arthur.     Heredity. 

TiLLEY,  Herbert.  The  Relationship  of  Nasal 
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Tomes  &  Nowell.     A  System  of  Dental  Surgery. 

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Turner,  J.  G.  Trans.  B.S.S.O.,  Oct.  1908 
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Turner,  J.  G.  Report  on  Phenomena  found  in 
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Vandervelde,  Emile.     Evolution  by  Atrophy. 

VowLES,  F.  Tension  Springs  in  Orthodontia. 
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VisiCK,  Hedley  C.  a  Case  of  Open  Bite. 
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VisicK,  Hedley  C.  The  Northcroft  Plaster- 
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Wallace,  J.  Sim.     Irregularities  of  the  Teeth. 

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Wallace,  J.  Sim.  Trans.  B.S.S.O.,  Feb.  1911. 
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Waugh,  Leuman  M.  The  Laws  of  Antagoniza- 
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Weeks,  S.  Merrill.  Consideration  of  the 
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Weismann,  A.  The  Germ  Plasm — A  Theory  of 
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Whipple,  J.  Double  Resection  of  the  Inferior 
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Whitaker,  W.  R.  H.  Rollinson.  The  Relation- 
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.June  1,  1911,  Vol.  XXXII,  p.  537. 

Willis,  F.  M.  Rapid  Separation  of  the 
Superior  Maxillary  Bones  to  relieve  Defieeted 
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166 


(173)  Wright,   Geo.  H.     Deformities   of    the    Nasal 

Respiratory  Tract.     Dental  Cosmos,  Mar.  1912, 
Vol.  LI V.  p.  261. 

(174)  Wright,  William.     The  Teeth  and  Jaws  of  a 

Series  of  Prehistoric  Skulls.     Brit.  Dent.  Jour., 
1903,  Vol.  XXIV,  p.  57. 

(175)  YoNGE,    E.    S.     Abnormalities    in    Relation    to 

Disease     of     Upper     Air     Passages.     Dental 
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(176)  yoTJNG,    J.    Lowe.     Early   Treatment   of   Mal- 


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397.     Discussion,  p.  665. 

(177)  Young,  J.  Lowe.     Deficient  Development  of  the 

Arches  of  the  Deciduous  Teeth  and  the 
Necessity  of  Early  Treatment.  Dental  Cosmos, 
1910,  Vol.  LII,  p.  1185. 

(178)  Zeliska,  Franz.     The  Influence  of  the  Atmo- 

spheric Pressure  upon  the  Moulding  of  the 
Dental  Arch.  Dental  Cosmos,  1905,  Vol.  XL VII, 
p.  583. 


CHAPTER  VIT 


ABNORMALITIES   OF   POSITION— TREATMENT   BY  MEANS   OF 

APPLIANCES 


The  purpose  of  this  chapter  is  to  deal  with 
the  treatment  of  orthodontical  cases  ;  with  the 
movement  of  the  teetli  and  associated  struc- 
tures ;  and  with  the  retention  of  these  move- 
ments till  the  teeth  have  become  fixed  in  their 
new  positions,  and  the  tendency  to  relapse 
has  been  overcome  by  natural  means,  i.  e.  by 
the  establishment  of  physiological  equilibrium 
between  all  the  tissues  involved. 

The  previous  chapters  dealt  with  orthodontics 
from  the  aetiological  and  pathological  stand- 
points, so  that  the  object  of  this  will  not  be 
to  treat  of  the  subject  from  the  point  of  view 
of  different  classes,  but  according  to  the  tooth 
movements  that  are  to  be  performed.  The 
reasons  for,  and  directions  of,  these  movements 
have  been  decided  upon  before  this  aspect  of 
the  subject  has  been  taken  up. 

Tooth  movement  \\  ill  be  considered  in  two 
classes — 

I. — The  major  movements,  i.  e.  the  move- 
ment of  several  teeth  in  the  same 
direction  without  special  attention  to 
particularities  of  individual  teeth ; 

II. — The  minor  movements,  i.  e.  the  move- 
ment of  individual  teeth ; 

so  that  the  operator  may  select  and  plan  out 
the  course  of  treatment  by  reference  to  the 
following  paragraphs,  which  deal  with  all  the 
movements  he  is  likely  to  be  called  upon  to 
effect. 

The  object  here  is  to  treat  of  principles  rather 
than  of  particular  cases,  because  if  the  principles 
of  moving  teeth,  collectively  and  individually, 
in  all  directions,  are  thoroughly  grasped,  the 
orthodontist  will  have  no  difficulty  m  apj^ly- 
ing  them  in  their  various  combinations,  whereas 
it  would  be  impracticable  and  require  need- 
less repetition  to  deal  with  the  treatment 
of  numerous  actual  cases  covering  all  possi- 
bilities. Therefore,  the  operator,  having  de- 
cided what  tooth  movements  he  wishes  to 
accomplish  in  any  given  case,  and  having 
mastered  the  general  principles  mvolved  m  all 
cases,  such  as  anchorage,  adjustment  of  appli- 
ances, the  use  of  certain  accessories  common 
to  all  cases,  etc.,  must  refer  to  the  sections  deal- 
ing with  such  movements  in  order  to  learn  how 
they  are  to  be  brought  about,  and  not  expect 
to  find  an  exhaustive  exposition  of  the  treatment 


of  an  identical  case,  though  a  description  of 
several  typical  ones  will  conclude  this  subject. 
(See  pp.  239-240.) 

The  problems  that  present  themselves  in  any 
case  are  five — 

A.  Wliat  irregularities  are  present  ? 

B.  What  condition  is  it  desired  to  create  ? 

C.  \Vliat  movements,  major  and  minor,  are 

necessary  to  brmg  this  about  ? 

D.  How  shall  these   movements   be  accom- 

plished ? — i.  e.  treatment. 

E.  How,  and  for  how  long,  are  these  move- 

ments to  be  artificially  retained  ? — i.  e. 
retention. 

Problems  A,  B,  and  C  are  dealt  with  in  Chapters 
IV,  V,  and  VI,  but  as  they  are  questions  that 
are  vitally  connected  with  treatment  it  will 
not  be  out  of  place  to  refer  to  them  again,  but 
entirely  from  the  point  of  view  of  treatment. 

A.  What  irregularities  are  present  ? 

These  must  not  be  considered  from  the  point 
of  view  of  an  obvious  dental  irregularity,  but 
from  the  standpoint  of  teeth,  jaws,  and  face — 
the  tout  ensemble  of  which  is  concerned  in  the 
irregularity ;  the  malocclusion  is  not  a  purely 
dental  defect — generally  speaking — but  an  error 
in  bony  development  of  which  the  misjalaced 
teeth  are  an  expression.  If  regard  is  paid  to 
only  one  very  obvious  deformity,  such  as  lin- 
guaUy  placed  laterals,  and  that  alone  treated, 
the  grosser  deformities  that  are  rarely  insepar- 
able from  this  being  disregarded,  it  would  be 
found  later  that  the  case  was  little  if  any 
better  than  at  first.  Each  dental  arch  must  be 
considered — 

(1)  per  se  ; 

(2)  m  relation  to  its  fellow ; 

(3)  in  relation  to  the  face. 

It  is,  therefore,  of  the  utmost  importance  to 
decide  upon  all  the  deviations  from  normal  in 
every  case. 

1       B.  Wliat  condition  is  it  desu-ed  to  create  ? 

1  Having  decided  what  irregularities  are  present, 
the  next  point  to  decide  is  w:hat  condition — 
what  positions  of  the  teeth  and  jaws — shall  be 
the  goal  ? 


167 


168 


(1)  Shall  it  be  normal  occlusion  ?  This 
implies  the  normal  relation  of — 

(a)  The  teeth  of  either  jaw  to  one  other ; 

(b)  The  teeth  of  one  jaw  to  the  teeth  of  the 

other  jaw ; 

(c)  The  jaws  to  each  other ; 

(d)  The  jaws  to  the  remainder  of  the  face. 

If  normal  occlusion  is  desired  and  to  be  sought, 
then  the  way  is  clear  when  once  the  irregularities 
have  been  diagnosed. 

(2)  Shall  it  be  some  de\aation  from  that  ideal 
(normal  occlusion),  which  topical  exigencies 
may  necessitate  ? 

These  exigencies  include — • 

(a)  Absence  of  teeth — congenital  or  due  to 

operative  procedure. 

(b)  The   time   and   opportunity   to   undergo 

treatment  sufficiently  prolonged  to 
establish  normal  occlusion  may  not  be 
available. 

If  there  must  be  any  departure  from  the  ideal 
of  normal  occlusion  the  following  points  deserve 
careful  consideration  in  arriving  at  a  decision — 

(a)  Whether  it  is  possible  to  establish  good 
approximal  contact  between  all  adja- 
cent teeth — avoiding  aU  spacing. 

(6)  Whether  it  is  possible  to  establish  an 
occlusion  that  is  perfect  for  the  teeth 
that  remain  ;  with  thLs  is  included  the 
tnter-digitation  of  cusps  both  medio- 
distally  and  bucco-lingually. 

(c)  Whetlier    it    is   possible    to    produce   an 

aesthetic  result. 

C.  What  movements,  major  and  minor,  are 
necessary  to  bring  this  about  ? 

The  previous  chapters,  supplemented  by  the 
preceding  paragraph,  fuUy  answer  this  question, 
which  includes  the  direction  of  movement  of 
every  tooth  ;  and  the  greatest  factor  in  deciding 
this  is  the  aesthetic  one,  normal  occlusion  of 
course  beuig  coupled  with  it.  If  it  is  decided 
that  any  particular  tooth  is  in  its  absolutely 
correct  position,  such  as  an  upper  central  or 
fir.st  permanent  molar,  it  is  not  difficult  to  build 
up  a  dental  arcli  from  such  fixed  point,  and  so 
decide  the  movement  each  tooth  must  undergo. 

D.  How  sliall  these  movements  be  accom- 
plished (treatment)  ? 

E.  How,  and  for  ho\\-  long,  are  these  move- 
ments to  be  artificially  retained  (retention)  ? 
(See  Chapter  X.) 

The  answ  er  to  these  two  ([uestions  demands  a 
consideration  of  the  subject  of  appliances,  and 
to  this  problem  considerable  space  must  be 
devoted — in  fact,  the  remaining  pages  allotted 
to  this  subject, — as  it  bears  on  the  practical 


aspect  of  the  practice  of  orthodontics.  Before 
passing  to  it.  however,  the  writer  wishes  to  direct 
attention  again  for  a  moment  to  question  (B) 
and  its  answer,  but  in  another  form,  as  he  is  of 
ophiion  that  therein  lies  the  secret  of  failure  or 
success. 

One  not  infrequently  sees  cases  under 
treatment,  of  \\hich  the  operator  has  formed  no 
clear  opinion  of  the  ultimate  result  he  \\-ishes  to 
produce.  It  is  superfluous  to  emphasize  the 
futility  of  such  a  proceeding. 

The'  operator  must  have  an  object  in  view ; 
he  must  aim  for  that  object  and  strive  to  the 
very  utmost  to  attain  it.  The  latter  is  not  the 
greatest  difficulty  in  orthodontics ;  often  it  is 
a  greater  difficulty  to  decide  \\hat  tlie  object 
shaU  be,  but  as  this  must  be  done  before  the 
treatment  of  any  case  is  undertaken,  the 
orthodontist  has  set  himself  a  task  ;  and  having 
accomplished  it — having  attained  his  object — 
has  reached  the  greatest  difficulty,  the  mainten- 
ance of  the  new  conditions.  But  now  there  is 
no  reason  to  believe  that  he  mUI  allow  the  result 
of  his  labours  to  be  rumed  by  neglecting  this  of 
wliicli  he  may  be  proud;  he  will  grapple  -with 
the  problem  with  greater  pertinacity  in  order 
that  the  prize  may  not  be  lost.  Tlie  problem 
is  not  merely  to  work,  but  to  work  with  an 
object.  The  object  has  been  set  before  the 
orthodontist,  but  probably  no  branch  of  dentis- 
try requires  greater  perseverance,  concentration, 
and  continuity,  that  it  shall  not  be  beyond  his 
reach. 

D.  How  shall  these  movements  be  brought 
about  ? 

Treatment. — This  division  of  the  subject  deals 
with  the  actual  movement  of  teetli,  and  demands 
a  consideration  of  appliances  and  their  choice. 

An  orthodontical  appliance,  whatever  its 
nature,  is  a  macliine  constructed  to  do  certain 
work  for  which  a  liigh  standard  of  efficiency  is 
necessary.  Efficiency  is  the  one  essential 
property  that  aU  must  possess  (apart  from  their 
otlier  advantages  or  disadvantages) ;  without 
this  they  are  worse  than  useless.  But  it  must 
be  constantly  borne  in  mind  that  efficiency  does 
not  depend  solely  on  the  appliance,  but  to  a 
much  greater  extent  on  its  application  and  use ; 
that  is  to  say,  whatever  form  of  appliance  is 
used,  the  way  in  which  it  is  to  do  its  work 
must  be  thoroughly  grasped,  and  it  must  be 
applied  with  sucli  care  and  thought  tliat  it  will 
not  fail  to  jiroduce  the  desired  results.  The 
importance  of  tliis  statement  cannot  be  impressed 
too  forcibly,  and  as  a  practical  example  it 
need  only  bo  remembered  that,  by  means  of 
tlie  wire  bow,  any  tooth  movement,  and  almost 
any  combination  of  tooth  movements,  at  one 
and  the  same  time,  are  possible ;  it  is  obvious, 
tlien,  that  it  is  of  the  greatest  importance  that 
whatever  appliance  is  used,  should  be  arranged 


169 


for  those,  and  only  those,  movements  that  are     to  which  various  attachments  are  soldered  (see 
intended — neither  more  nor  less.  p.  217). 


These  are   intended  to 


APPUANCES  (2)  VuLCAMTE  Appliances 

Appliances  may  be  conveniently  divided  into  (a)  Plates    not    designed   for    expansion    (see 

two  classes—  "  Figs.   303,   308,   291).     ~ 

A.  Fixed, 

B.  Removable, 

according  as  it  is  impossible  or  not  for  the 
patient  to  remove  them  from  the  mouth  without 
difficulty. 

The  Nature  of  the  Variocs  Appliances 

A.  Fixed. — All  fixed  appliances  are  on  the 
same  principle ;  they  consist  essentially  of  a 
wire  bow,  and  bands  to  which  it  is  attached 
(see  Fig.  287).    The  wire  bow  passes  across  the 


Fig.  271. — Schelliugs  moditication  of  a  Coflki  plate. 
In  this  instance  the  spring  is  designed  to  obtain 
the  greatest  amount  of    expansion  in  the    canine 
region. 


17  7 


Fig.    270. — Vulcanite   expansion   plate   of   the   Coffin- 
spring  type. 

There  are  two  spurs  in  one  half  of  the  plate 
fitting  two  tubes  in  the  other  half,  wliieh  keep 
the  two  halves  ia  correct  relation  to  one  another. 
WTien  the  spring  is  altered  there  is  a  tendency  for 
the  relation  of  the  halves  to  one  another  to  be 
disturbed.  If  guide-wires  are  not  used  there  are 
clasps  of  platinized  gold  on  the  deciduous  canines 
and  first  permanent  molars  to  hold  the  plate 
in  situ. 

buccal  surfaces  of  the  teeth  and  fits  into  tubes 
soldered  to  the  bands,  which  have  been  at- 
tached to  one  of  the  back  teeth  (deciduous 
molar,  premolar,  or  permanent  molar).  By 
means  of  ligatures  and  various  attachments 
every  tooth  may  be  brought  under  control. 
As  devised  by  Angle  they  are  simple,  practical, 
and  efficient ;  they  can  be  used  to  deal  with 
simple  and  complex  cases  equally  well. 

B.  Removable. — (1)    Metal     appliances;     (2) 
Vulcanite  appliances. 

(1)  Metal  Appliances 

(a)  Plates    similar    to    vulcanite    plates,    the 
description  of  which  will  apply  to  these  also. 

(b)  Jackson  Appliances,  consisting  of  a  base  of 
pure  tin  fitted  to  the  necks  of  some  of  the  teeth, 

6* 


Fig.  272. — Badcoek  screw. 

1.  The  middle  of  the  screw  is  in  the  form  of 
a  square  boss,  whereby  the  screw  is  turned;  one 
end  of  the  screw  is  smooth  and  rotates  in  the 
tube, 

2.  from  wliich  it  cannot  be  removed. 

3.  The  other  end  of  the  screw;  it  is  threaded 
to  correspond  with  the  thread  on  the  tube. 

4.  of  the  design  shown  to  hold  it  in  the  \iilcanite. 

5.  A  plain  wire  soldered  to  (4)  and  shaped  as 
shown,  the  free  end  entering  the  tube, 

6.  which  is  roughened  to  hold  it  in  the  vulcanite ; 
this  accessory  is  to  prevent  the  two  halves  of  the 
plate  rotating  on  one  another. 

7.  A  wire  tag,  which  holds  the  screw  in  the 
flask  for  packing.  It  is  removed  after  viilcaniza- 
tion. 

8.  A  metal  tag  on  (2)  to  hold  it  in  the  vulcanite 
and  prevent  its  rotation. 

To  obtain  a  definite  degree  of  expansion, 
measure  the  amount  on  the  screw,  coimt  the 
niunber  of  threads  exposed,  and  direct  the  patient 
to  tiun  the  boss  completely  round  that  number  of 
times.  A  quarter  of  a  turn  everj'  other  day  is  a 
convenient  rate  at  wliich  to  proceed.  This  repre- 
sents nearly  one  complete  turn  per  week. 

produce  movement  of  individual  teeth  imder 
separate  control,  or  simple  collective  move- 
ments of  several  teeth.  Springs  and  the  elas- 
ticity of  rubber  are  the  forces  most  generally 
employed. 


170 


{b)  Plates  designed  for  ex'pansion  of  the  dental 
arches  (they  may  in  addition  f)rodiice  other 
necessary  movements). 

There  are  numerous  forms  of  these,  the 
important  ones  being — 

■•;  (i)  Coffin  Plate,  operated  by  piano-wii-e  spring 
(see  Figs.  270,  271,  301). 


Fig.  27.3. — Highton  device. 

A.  The  device  complete. 

B.  The   halves   of   the   device,   the   back   and   front 
having  been  removed. 

C.  The  inner  side  of  the  back  of  the  device  with 
parallel  ribs  to  prevent  its  rotation. 

D.  The   inner   side   of   the   front   of    the   device   on 
which  is  the  raised  spiral  cam. 

E.  The  back  of    the  device  which,  with    the  screw, 
clamps  all  the  parts  together. 

1.  The  outer  and  exposed  portion  of  D  with 
a  groove  for  turning  with  a  screw-driver. 

2.  Flanges  for  holding  the  device  in  the  vxilcanite. 

3.  The  sides  of  the  expanding  portion  of  the 
device,  through  which  movement  is  transmitted 
to  the  vulcanite. 

4.  Lateral  flanges  lying  between  the  ribs  on  C. 

5.  Central  flanges  which  lie  in  the  central  groove 
of  C.  These  flanges  have  raised  ends,  which  engage 
the  spiral  cam  on  D,  the  turning  of  which  forces 
these  two  flanges  apart. 

The  two  lateral  holes  on  E  enable  the  parts 
of  the  appliance  to  be  kept  clamped  together. 

(ii)  Reed  Screw,  operated  by  a  screw  in  a 
threaded  tube;  a  jack-screw  may  be  used  in 
the  same  way. 

(iii)  Badcock  Plate,  operated  by  a  screw  in  a 
threaded  tube,  the  screw  not  being  du'ectly 
attached  to  the  vulcanite  as  in  the  Reed  screw 
(see  Figs.  272,  274). 

(iv)  Highton  Device,  operated  by  a  spiral  cam 
(see  Figs.  273,  275). 

Cast  metal,  such  as  gold,  tm,  Gartrell's  metal. 


or  Brophy's  metal,  may  be  used  to  replace  the 
vulcanite  in  these. 


Advantages  and  Disadvantages  of  Fixed  Appliances 


Advantages. 

The  greatest  effici- 
ency of  any  appliance. 
Give  individual  control 
of  every  tooth.  Every 
tooth  movement  pos- 
sible. Not  under  con- 
trol of  tlie  patient  and 
must  be  worn.  Least 
liability  to  displace- 
ment. Least  inter- 
ference with  speecli 
and  the  other  func- 
tions of  the  mouth. 
Least  discomfort  and 
bulk  of  any  appliance. 
Must  operate  constant- 
ly if  properly  adjusted. 
Infrequent  necessity  to 
change  the  appliance. 
May  act  as  a  retaining 
appliance. 


Disadvantages. 

In  many  cases  re- 
quire skilled  attention 
once  a  week. 

The  length  of  time 
required  for  adjust- 
ment. 

Some  few  patients 
will  not  trouble  to 
exercise  the  necessary 
cleanliness. 

More  of  the  opera- 
tor's time  required  to 
maintain  the  efficiency 
of  the  appliance,  but 
this  is  more  than  com- 
pensated for  by  in- 
creased efficiency. 


Advantages  and  Disadvantages  of  Eemovable 
Appliances 


Advantages. 

In  simple  cases  one 
appliance  will  satis- 
factorily perform  the 
work;  these  eases  are 
few.  Cleanliness  has 
been  urged,  but  some 
patients  do  not  keep 
the  mouth  clean  Mith 
these. 

Controlled  by  pa- 
tient (not  always  an 
advantage),  if  screws 
or  rubber  is  used. 

If  scre\\'s  only  are 
used  to  exert  force,  the 
appliance  may  be  used 
passively  as  a  retainer. 
May  be  inconspicuous. 


Disadvantages. 

Liability  not  to  be 
worn.  New  appliances 
more  frequently  neces- 
sary, as  the  various 
movements  capable  of 
beuig  produced  are 
limited,  and  adjust- 
ment beyond  a  certain 
pomt  is  impossible. 

Greater  bidk. 

Liability  to  be  dis- 
placed. 

Individual  control 
of  every  tooth  impos- 
sible. 

In  some  cases  patient 
may  lisp  temporarily. 


(1)  Metal  Appliances. 

(a)  Plates. 

Advantages.  Disadvantages. 

Strength.  Time    and    expense 

necessary  for  construc- 
tion may  be  out  of  pro- 
portion to  the  work  to 
be  performed. 


171 


(b)  Jackson  Appliances. 

Advantages.  Disadvantages. 
Can  be  made  to  per-         Complicated  if  many 
form  a  large  number  of  individual  tooth  move- 
tooth     movements    at  ments  have  to  be  per- 
one  time.     Low  cost  of  formed.       Adjustment 
material    used    in    its  of  the  various  springs 
manufacture.          Does  difficult, 
not  entirely  cover  the 
mucous   membrane   of 
the  palate. 

(2)   Vulcanite  Appliances. 

(a)  Plates  not  designed  for  Expansion  of  the 
Dental  Arches. 

Advantages.  Disadvantages. 

Ease  of  construction         Efficiency  limited  to 

and   manipulation,  re-  few  tooth   movements 

quiring   little   time   to  at  one  time, 
adjust. 

(b)  Plates  designed  for  E.xpansion  of  the 
Dental  Arches. 

General. 
Advantages.  Disadvantages. 

Expansive  force  ex-         May    be     worn     or 
erted  directly  on  to  bone     not,   according  to   the 
as  well  as  on  to  teeth,     patient's  mclination. 
Appliance  can  be  made 

and  fitted  at  much  less         No   individual    con- 
cost  of  time  to  patient     trol  of  all  the  teeth. 
and   operator  tlian   in 
the  case   of   fixed  ap- 
paratus. 

(i)  Coffin  Plate. 
Advantages.  Disadvantages. 

Rapidity  of  action.  Adjustment  easily 
Very  low  cost.  Force  upset.  Not  applica- 
can  be  applied  at  any  Ijle  in  lower  jaw.  An- 
dcsired  point  to  a  chorage  not  satisfac- 
limited  degree.  tory   when    the    teeth 

have  short  crowns. 
Not  under  the  patient's 
control. 

(ii)  Reed  Screw. 
Advantages.  Disadvantages. 

Ease  and  simplicity  The  two  halves  of 
of  construction.  the    plate    revolve    on 

one  another.  Conse- 
quent loss  of  rigidity 
and  impairment  of 
adaptability.  A  com- 
plete turn  of  the  screw 
must  be  made  —  the 
screw  havmg  a  high 
pitch ;  this  may  give 
too  much  expansion  at 
one  time. 


(iii)  Badcock  Plate. 

Advantages.  Disadvantages. 

One  of  the  best  forms  It  must  be  seen  that 

of     expansion     plate ;  the  back  pressure,  due 

operated    by    a    single  to  the  tendency  of  the 

nut ;  amount  of  expan-  teeth  to  relapse,  does 

sion  can  be  exactly  as  not  cause  the  screw  to 

desired.  The  two  halves  rotate  backwards.  The 


Fig.  274. — Vulcanite  Badcock  plate  in  position  to 
expand  molars,  premolars,  and  canines ;  in  this 
case  it  will  also  move  the  laterals  distally.  The 
vulcanite  point  between  tlie  centrals  should  be 
cut  off  so  as  not  to  carry  the  left  central  distally. 
Platinized  gold  wire  clasps  for  the  first  molars 
and  first  premolars  are  shown  holding  the  plate 
in  position. 

The  surface  of  the  plate  is  thickened  and 
inclined  forwards  and  upwards  to  open  the  bite 
and  bring  the  lower  jaw  forward. 


of  the  plate  do  not  re-     end   of   the    threaded 
volve  on  one  another,     tube  should  be  closed 
Good    rigidity    for    a     a   little  with  pliers  to 
divided  plate,  and  con-     prevent  this, 
sequently    it    may    be 
made    to    perform   ac- 
cessory      movements. 
Crib    clasps    may    be 
used    to    increase    its 

j  stability.  Applicable 
to  either  jaw.   In  order 

j  that  its  position  may 
be  maintamed  in  the 
lower  jaw  cleats  should 
engage  the  lingual  sul- 
cus of  the  first  molar ; 
and  in  order  that  the 
lingual  halves  may  ex- 
pand satisfactorily 
they  should  have  their 
rigidity  increased  by 
metal  inserted  in  the 
vulcanite. 


172 


(iv)  Highton  Device. 


Advantages. 

May  be  used  in  very 
Darrow  jaws ;  it  is  made 
in  two  sizes,  the  smal- 
ler of  \\hich  can  be 
employed  iii  the  smal- 
lest mouth.  No  lia- 
bility for  screw  to  turn 
back  due  to  inward 
pressure  of  expanded 
jaws.  The  patient  con- 
trols the  expansion, 
which  may  be  little 
or  much,  as  desired. 
Wlien  expanded  to  its 
full  extent  this  device 
can  be  re-fitted  and 
used  again. 


Disadvantages. 

Range  of  move- 
ment with  the  smaller 
device  very  slight ; 
therefore  change  should 
be  made  to  the  larger 
device  at  first  opportu- 
nity. Not  as  strong 
as  Badcock  plate. 


?5R? 


Fig.  275. — Highton  device  in  position  in  a  very  narrow 
lower  dental  arch. 

There  are  cleats  on  the  second  deciduous  molars 
to  prevent  the  plate  sinking  into  the  soft  tissues. 

To  obtain  the  best  results  from  removable 
appUances,  the  casts  used  to  make  these  should 
always  be  from  plaster  impressions,  in  order 
that  they  may  fit  perfectly ;  their  stability,  and 
with  it  the  anchorage,  is  increased  thereby. 

Wire  clasps,  or  other  wires  that  have  to  pass 
between  the  t\\o  teeth  near  their  contact  point, 
should  usually  be  strengthened,  as  they  not 
only  have  to  maintain  the  plate  in  position  but 
the  bite  of  the  opposite  jaw  often  comes  on  them. 
They  may  be  strengthened  and  made  to  fit 
very  accurately  by  burnishmg  platinum  into 
the  space  over  which  the  wire  will  pass ;  the 
clasp  wire  is  then  fitted  and  the  two  are  united 
with  solder.  The  fit,  rigidity,  and  strength  of 
the  clasp  is  thus  improved  whilst  its  power  to 
retain  the  plate  in  position  is  not  interfered 
with. 

As  it  frequently  happens  that  patients  can 
only  be  seen  at  long  intervals,  the  details 
regarding  the  accomplishment  of  any  tooth 
movement  with  removable  appliances  will  be 
dealt  with. 


(A)  Fixed  Appliances 

To  justify  their  name  these  must  possess  the 
power  to  remain  on  the  teeth — in  spite  of  any 
interference  on  the  part  of  the  patient  and  any 
force  applied  to  the  teeth  through  them — -which 
is  obtained  by  the  use  of — 

(1)  Clamp-bands,  and 

(2)  Oxy-phosphate  cements. 

When  these  are  used  in  combination  the 
cement  is  only  to  prevent  the  access  of  fluids  to 
tooth  surface  that  cannot  be  cleansed,  and  so 
prevent  decalcification  of  the  enamel,  though 
it  often  does  actually  increase  the  fixity  of  the 
band. 

Fixed  appliances  include  essentially — 

1.  Bands — 


Qamp  (see  Figs.  277,  278) 
Plain  (see  Fig.  337) 


For  the  attach- 
ment of  acces- 
sories, such 
as  tubes  and 
spurs. 


2.  Bows- 


Plain  (see  Figs.  280.  285)  1  Develop  force 
Ribbed  (see  Fig.  281)  'r  for  tooth 
Divided  (see  Fig.  282)      J      movement. 


Wliereby  teeth  and 
bows  are  con- 
nected with  one 
another,  and  teeth 
moved. 


3.  Ligatures — 

Wke  (see  Fig.  287) 
SUk  (see  Fig.  331) 
Rubber 

4.  Accessories — 

Buccal  Tubes  (see  Figs.  277,  276,  283) 
Nuts  (see  Figs.  281,  270,  271,  280c), 

1.  Bands 

Clamp-Bands. — These  are  necessary  for — 

(1)  Anatomical  reasons ; 

(2)  Mechanical  reasons. 

(1)  Atiatomical  Reasons. — The  circumference 
of  a  tooth  at  the  neck  being  less  than  at  the 
occlusal  surface,  it  is  unpossible  to  adjust 
satisfactorily  a  soldered  band  to  a  molar  tooth 
(except  possibly  in  the  case  of  teeth  where  the 
disproportion  is  least  pronounced) ;  hence  the 
anatomical  necessity  for  a  clamp-band  ;  so  that 
it  may  be  passed  over  the  greatest  diameter 
of  the  tooth,  and  the  ends  di'awn  together  to 
embrace  clo.sely  every  portion  of  the  tooth. 

(2)  Mechanical  Reasons. — If  a  soldered  band 
can  be  placed  on  a  tooth  without  adjustment  it 
can  similarly  be  removed  from  the  tooth ;  that 
is  to  say,  its  attachment  to  the  tooth  depends 
solely  on  cementation  (except  in  so  far  as 
burnishing  may  be  able  to  adjust  the  band  to 


173 


the  neck  ;  but  on  this  procedure  little  reliance  is 
to  be  placed).  In  the  case  of  a  clamp-band, 
however,  it  is  impossible  to  remove  the  band 
(if  properly  fitted)  intact  from  a  tooth  without 
loosening  the  nut. 

These  bands  are  the  basis  of  security  of  fixed 


(D 


^ 


a 


of  band  material  is  suitable.  These  bands 
should  always  be'  cemented  on,  to  prevent  the 
ingress  of  the  oral  fluids  between  the  band 
and  the  tooth. 

The  width  of  clamp-bands  is  such  as  to 
correspond  approximately  with  the  depth  of 
enamel  on  a  tooth — -it  is  not  greater  than  this ; 
and  as  enamel  has  no  attachments  to  its  outer 
surface  it  is  unnecessary,  except  in  rare  instances, 


Fig.  276. — The  part.s  of  a  clamp-band. 

1.  The  band  proper. 

2.  Threaded  wire  soldered  to  the  band  material 
on  whicli  the  nut, 

3.  runs  to  engage 

5.  a  short  length  of  tube,  soldered  at  the  oppo- 
site end  (but  not  at  the  edge)  of  the  band  proper, 
through  which  the  tlireaded  wire  passes. 

6.  Kound  buccal  tube  in  plan,  the  end  that  is 
to  be  distal  being  bevelled. 

7.  Round  buccal  tube  in  section. 

4.  Solder  flowed  on  the  centre  of  the  band 
preparatory  to  attacliing  the  buccal  tube. 

appliances.  They  support  the  bows,  so  that 
it  is  vital  to  successful  manipulation  that  they 
shall  be  securely  held  on  the  teeth.  This 
object  is  attained  by  the  proper  adjustment  of 
the  component  parts  (see  Fig.  276) : 

1 .  The  band  proper— a,  straight  piece  of  band 
material  of  suitable  length. 

2.  The  clamping  mechanism — it  consists  of — 

5.  A  short  length  of  tube  soldered  a  short 
distance  from  one  extreme  edge  of  the 
band. 

2.  A  length  of  threaded  wire  on  which 
runs  a  nut  to  engage  the  tube  (5). 


Fig.   2 1  7. — All-closing  clamp-band  with  oval  tube. 

1,  2,  3,  and  5,  as  in  Fig.  276. 

6.  Oval  buccal  tube. 

7.  Oval  buccal  tube  in  section. 

Xotice  that  when  the  band  is   closed  its  ends 
overlap. 

The  tube  (5)  is  placed  so  far  from  the  end  of 
the  band  that  when  it  is  tightened  up  the  tooth 
will  be  completely  encircled  by  the  band  proper, 
not  leaving  any  intermediate  tooth  surface 
exposed  to  the  oral  fluids  ;  a  band  so  con.structed 
may  be  fitted  to  any  tooth,  provided  the  length 


Fio.  278. — Luken's  band. 

1.  The  band  proper. 

2.  The  buccal  tube,  which  is  also  the  clamping 
mechanism ;  it  is  threaded  externally,  and  cut 
square  at  one  end  to  serve  as  a  nut. 

3.  Plain  tube  on  the  end  of  the  band  nearer 
the  nut  (or  square  end). 

4.  Tube  threaded  internally  in  which  the  buccal 
tube  tiu-ns. 

(a)  Cross-section  of  buccal  tube. 

to  cut  the  band  at  all  narrower  ( deciduous 
molars  excepted,  as  these  are  shorter  teeth). 
This  is  obviously  an  unwise  procedure  as  the 
surface  area  of  material  is  reduced,  and  so 
the  attachment  to  the  tooth  is  reduced,  and 
the  stability  of  the  baud  thereon  is  affected — 
it  has  already  been  stated  that  the  clamp-band 
is  the  basis  of  fixity  of  fixed  appliances. 


Fig.  279. — Clamp-band  for  a  premolar,  where  the  tube 
has  to  be  placed  more  distally  than  for  a  molar, 
or  else  the  threaded  portion  of  the  bow  might  not 
be  long  enough.  The  tube  is  held  away  from 
direct  contact  with  the  band  material  by  an 
intervening  piece  of  wire ;  this  is  necessary  in 
those  cases  in  which  the  adjacent  teeth  prevent 
the  tube  assimiing  its  correct  position. 

To  the  lingual  aspect  of  the  band  an  extension 
spur  is  soldered  to  engage  the  first  molar,  so  that 
it  may  be  included  with  the  premolar  as  it  expands 
buccally. 

A  tube  soldered  to  the  buccal  surface  of  the 
clamp-band  is  the  medium  whereby  the  bow  and 
band  are  connected. 

Another  form  of  clamp-band,  the  Luken's  (see 
Fig.  278),  is  that  in  which  the  tube  and  clamping 
arrangement  are  combmed,  leaving  one  surface 
free  of  attachments.  The  bolt  or  threaded  wire 
portion  is  hollow,  and  thus  becomes  the  tube ; 
one  end  is  cut  square  and  serves  as  the  nut ; 
the  other  passes  through  a  short  plain  tube  on 
one  extremitv  of  the  baud  and  then  engages 


174 


a  tube,  threaded  internally,  which  is  soldered 
at  the  other  end  of  the  band,  and  is  the  means 
whereby  the  band  can  be  closed,  the  square 
end  of  the  bolt  engaging  the  plam  tube. 

The  ordinary  clanip-band  permits  the  adjust- 
ment of  the  buccal  tube  in  any  position  ;  the 
type  just  described  cannot  have  its  tube  placed 
in  any  du'ection  ;  this  will  be  better  appreciated 
when  the  fitting  of  clamp-bands  is  described. 

Clamp-bands  are  used  both  on  molars  and 
premolars  (see  Fig.  279) ;  they  are  to  be  had  in 
different  sizes  with  or  w  ithout  buccal  tubes. 

Plain  Bands  are  made  for  individual  teeth 
and  have  a  soldered  jomt ;  the  metals  most 
frequently  used  for  their  construction  are — 

(a)  Iridio-platinum  (10-30  per  cent) ; 

(b)  Platmized  gold ; 

(c)  German  silver. 

Of  the  first  two,  iridio-platinum  is  to  be 
preferred  on  account  of  its  greater  toughness 
when  very  thin  material  is  needed ;  y  uVir  inch 
is  a  suitable  thickness,  although  for  bands  on 
incisors,  which  have  not  to  withstand  much 
strain,  they  may  be  even  thinner.  On  account 
of  its  harshness  iridio-platinum  is  not  as  easily 
worked  as  platinized  gold. 

2.  Bows 

These  are  lengths  of  wiie,  in  which  "  spring  " 
may  be  developed,  and  in  other  ways  eSect 
the  movement  of  teeth ;  each  end  is  threaded 
and  furnished  with  a  nut ;   the   length  of  the 


Fig.  2S0. — Plain  bow. 

(a)  and  (b).  Sections  of  bows  of  different  gauges 
in  the  unthreaded  portion,  but  of  the  same  gauge 
in  the  threaded  portions. 

(c)  Split  nut,  whose  edges  may  be  brought 
closer  together,  so  that  it  will  turn  on  the  bow 
by  means  of  a  wrench  only. 

bow  is  such  as  to  embrace  the  dental  arch 
on  its  buccal  surface  from  the  first  molar 
on  one  side  to  the  first  molar  on  the  other 
side,  when  the  teeth  have  been  brought  into 
normal  occlusion;  as  the  wire  bow  must  not 
project  through  the  distal  ends  of  the  buccal 
tubes,  it   may  not   be  possible,  when  starting 


treatment,  to  use  one  that  will  be  sufficiently 
long  to  complete  the  operation.  The  bow  is 
threaded  sufficiently  from  either  end  to  accom- 
modate the  buccal  tube  and  nut,  whether  the 
tube  is  on  a  molar  or  premolar  band. 

A  plain  bow  (see  Fig.  280)  is  one  as  described 
above. 


Fig.  281. — Angle's  ribbed  bow. 

A.  The  bow  in  plan. 

B.  The  bow  and  rib  in  section. 

C.  The  nut  and  tube  m  section. 

1.  The  rib. 

2.  The  bow  proper. 
3  and  4.   The  nut. 

3.  The  square  end  of  tlie  nut. 

4.  The  circular  extension  of  the  nut  to  fit  in 
the  sleeve  (6),  which  forms  the  front  portion 
of  the  buccal  tube. 

5  and  6.   The  buccal  tube. 

5.  The  main  portion  of  the  tube  which  the 
bow  fits  exactly. 

6.  The  front  of  the  tube  enlarged  to  receive 
the  circular  extension  (4)  on  the  distal  end 
of  the  nut,  which  it  fits  acciurately. 

A  ribbed  bow  (see  Fig.  281)  is  one  that  has  on 
its  outer  surface  a  flat  piece  of  metal  extending 
about  f  of  an  inch  on  either  side  of  its  centre. 
Its  special  function  is  to  facOitate  medial  and 
distal  movements  of  the  incisor  teeth. 

A  divided  how  (see  Fig.  282)  is  one  that  is 
composed  of  three  pieces  ;  that  is  to  say,  a  plain 
bow  is  divided  in  the  centre,  the  two  new  ends 
thus  formed  are  threaded,  and  nuts  run  on 
them  ;  they  then  pass  mto  a  tube,  about  half  an 
inch  in  length  (one  at  each  end)  the  extremities 
of  which  are  engaged  by  the  nuts. 

3.  Ligatures 

Brass  wii'e  is  usually  used  for  ligatures ;  two 
sizes,  26  and  28  American  gauge  (Browii  and 
Sharp),  are  most  frequently  employed. 

Silk  is  also  used,  that  form  kno\TO  as  Japanese 
grass  line  being  the  most  suitable.  It  con- 
tracts considerably  when  moistened.  It  is  to 
be  obtained  in  several  sizes. 

Rubber  ligatures,  or  rather  rubber  rmgs,  are 
made  by  cutting  short  sections,  varying  in 
width,  of  black  rubber  tubing.  Tubing  of 
several  different  diaineters  is  desirable. 


175 


The  bow  is  attached  to  the  clamp-bands 
tlirough  the  medium  of 

4.  Accessories 

Buccal  Tubes. — Tliese  are  usually  round  (see 
Figs.  276,  278,  279,  281,  288,  a),  and  then, 
whatever  the  vertical  position  of  the  anchor 
tooth  due  to  movement,  the  bow  will  always 
engage  them ;  ui  other  words,  the  relationship 
of  the  long  axis  of  the  tooth  with  the  vertical 
may  vary  \\'ithout  affecting  the  adjustment 
(see  Fig.  286).  Other  tubes  have  been  designed 
to  keep  this  relationship  constant. 

A  method  of  doing  this  is  to  replace  the  round 
tube  by  a  square  buccal  tube.  A  special 
attachment  is  soldered  to  the  end  of  the  bow, 
which  accurately  fits  this  tube.  The  nut  must 
be  put  on  before  the  special  threaded  square 
tube  is  soldered  to  the  bow. 

Another  method  is  by  means  of  an  Otto- 
lengui  tube ;  in  this  case  a  flange  is  soldered  to 
the  bow  where  it  enters  the  tube,  which  is  split 
to  accommodate  it.  The  simplest  method  is 
to  use  an  oval  tube  (see  Figs.  277,  288,  b), 
and  a  bow  whose  threaded  ends  are  flat  and 
accurately  fit  the  buccal  tube  (see  Fig.  280,  a 
and  6).  Tliese  devices  are  used  when  it  is 
desired  to  increase  the  resistance  of  the  banded 
tooth  to  movement,  as  with  them  translational 
movement  only  is  possible  (see  Fig.  286). 

Nuts. — The  nuts  on  the  bow  are  subject  to 
considerable  friction  from  the  cheeks,  which  is 


Fig.  282. — Divided  bow. 

(a)  Lateral  portions ;  each  medial  end  is  flattened  and 

threaded  to  receive  a  nut,  in  addition  to  the  losual 
thread  on  this  part  of  the  bow. 

(b)  Central    portion,    an    oval    tube,    into    which    the 

anterior  ends  of  the  lateral  portions  fit  accurately  ; 
a  nut  engages  each  end  of  the  tube  to  permit  of 
great  expansion  in  the  canine  region. 

often  sufficient  to  turn  them  ;  this  is  very  un- 
desirable. The  best  means  of  obviating  this  is 
by  an  extension  of  the  nut  (see  Fig.  281,  4), 
which  fits  mto  the  front  of  the  buccal  tube, 
which  has  been  counter-sunk  for  this  purpose. 
The  idea  is  a  patent  of  Angle's,  and  so  not  to 
be  had  on  any  appliance  except  those  sold  under 


his  name.  Other  devices  have  been  used  with 
varying  success ;  an  efficient  one  is  a  split  nut 
(see  Fig.  280,  c),  whose  edges  may  be  brought 
closer  together  when  occasion  demands  it. 

Materials  used  in  the  Construction  of  Bands  and 
Bows 

The  clamp-bands  and  bows  are  usually  made 
of — 

(1)  Platinized  gold,  or 

(2)  German  silver. 

The  former  are  more  easily  worked,  and  more 
easily   cleaned   and  kept  clean ;    bows  of   this 


-"^ 


Fig.   283. — Ottolengui  tube. 

1.  Threaded  tube  with  flange  (a)  into  which  tlie  bow 
passes  and  to  whicli  it  is  soldered  so  tliat  (a) 
engages  the  split  portion  of  the  buccal  tube  (6) 
seen  in 

2  and  3,  which  show  tlie  split  tube,  engaged  by  the 
flange  (a)  in  two  positions. 

4.  Shows  the  bow  (c)  passing  into  the  threaded  tube 
which  carries  the  flange.  Bow  and  tube  are 
soldered  to  one  another  so  that  their  relation 
may  not  be  variable. 

material  are  more  efficient,  and  do  not  greatly 
deteriorate  in  appearance  with  use. 

German  silver  is  cheaper.  The  metal  de- 
teriorates in  the  mouth,  and  in  the  case  of 
bows  these  consequently  lose  their  springiness 
in  time,  and  a  new  bow  may  have  to  be 
employed.  German  silver  appliances  are,  there- 
fore, less  efficient ;  it  is  more  difficult  to 
preserve  their  good  appearance  (and  later, 
impossible),  and  they  are  more  liable  to  need 
renewal. 

C.  J.  Grieves  (3)  has  conducted  a  number  of 
very  valuable  ex|)eriments  as  to  the  merits  and 
demerits  of  the  various  metals  and  alloys  used 
in  the  mouth  for  orthodontical  appliances.  His 
conclusions  are  that  every  band  should  be 
cemented  to  the  tooth,  as  in  this  way  only  can 
the  enamel  be  protected  against  decalcification ; 
and  that,  from  the  point  of  view  of  decalcifi- 
cation,  German  silver,  unplated,  is  the  least 


176 


harmful  material  that  can  be  used  when  un- 
cemented,  but  that  it  is  to  be  rigidly  condemned 
because  it  corrodes  so  readily,  and  becomes 
dirty  even  on  the  exposed  surfaces  that  can 
usually  be  kept  clean.  The  alloys  of  the  precious 
metals,  the  preference  being  given  to  platinized 
gold,  are  the  most  desirable  materials  with 
which  to  make  aiipliances :  they  practically  never 
corrode,  though  prophylactic  treatment  is  essen- 
tial every  t^\'o  weeks  or  so  to  cleanse  surfaces 
exposed  to  metal  but  not  jirotected  by  cement. 
Any  discoloration  of  these  appliances  is  due 
to  deposit  of  sulphides  and  not  to  corrosion, 
unless  zinc  is  in  the  alloy.  Removable  ap- 
pliances do  less  harm  than  fixed  ones;  they 
should  not  fit  the  teeth  too  accurately,  but 
only  touch  them  at  a  sufficient  number  of 
points  to  give  stability.  Where  there  is  no 
contact  between  tooth  and  metal  the  space 
should  be  large  enough  for  the  easy  passage  of 
saliva,  which  dilutes  the  decalcifying  acids. 

Grieves  fovuid  that  wherever  food  retention 
centres  occurred,  the  enamel  was  frequently  de- 
calcified ;  deposits  of  dark  salts  were  formed  on 
the  roughened  enamel,  but  the  stain  caused  was 
removed  by  buffing.  In  conclusion,  wherever 
cleanliness  was  not  possible,  in  that  situation 
there  was  a  potential  source  of  injury  to  tooth 
structure.  The  explanation  of  these  phenomena 
is  that  electrolysis  is  set  \vp  between  the  metal 
and  tooth ;  when  the  metal  is  one  easily  attacked 
by  acids,  then  the  effect  is  seen  there  ;  but  when 
the  metal  is  one  less  easily  affected  than  tooth 
structure,  then  the  latter  is  the  sufferer.  In  the 
same  paper  the  composition  and  properties  of 
various  alloys  used  in  orthodontics  is  discussed. 

Fitting  of  Clamp-bands 

Separation  on  each  side  of  the  tooth  to  be 
banded  often  facilitates  the  operation,  though 
not  essential  in  all  cases.  Tliis  can  be  done 
by  means  of  ligature  silk  around  which  a  little 
cotton-wool  has  been  wrapped,  passed  through 
the  inter-proximal  space  and  then  tied  round  the 
contact  point  of  the  two  teeth.  Lowe  Young 
recommends  the  use  of  heavy  ligature  wire  in 
the  same  way,  but  without  any  cotton-wool. 
He  also  uses  ligature  silk ;  he  passes  a  double 
strand  through  the  inter-proximal  space  by 
means  of  floss  silk;  a  double  strand  of  this 
is  passed  between  the  two  teeth,  and  the 
ligature  silk  made  to  engage  the  looped  end ; 
the  ligature  sUk  can  then  be  drawn  tlirough  the 
space  by  the  floss  silk,  which  is  now  removed ; 
one  free  end  of  the  ligature  silk  is  made  to 
engage  tlie  looped  end,  the  two  ends  are  pulled 
tight,  and  securely  tied.  The  shrinkage  of  the 
silk  wlien  wet  (it  should  be  applied  dry)  is 
sufficient  to  give  the  required  separation,  which 
need  only  be  slight.  If  it  were  greater  the 
liability  to  periodontitis  would  be  increased,  and 


the  fitting  of  the  band  \\ould  have  to  be  post- 
poned till  this  had  subsided.  Both  bands  and 
bows  need  preparation  before  they  can  be  fitted 
in  the  mouth.  A  band  of  suitable  lengtli  must 
be  chosen — such  that  when  it  is  properly  fitted 
the  ends  overlap,  and  the  portions  of  the  band 
to  which  the  clamping  parts  are  attached  are 
almost  in  contact ;  it  must  then  be  shaped  to 
tlie  outline  of  the  tooth  ;  for  this  purpose  Peeso 
pliers  (see  Fig.  689 ;  one  beak  is  flat  and  the  other 
rounded  and  a  trifle  shorter ;  both  are  smooth) 
serve  admirably.  The  shapmg  shoidd  be  done 
so  that  the  nut  will  coincide  with  the  inter- 
proximal space  between  the  tooth  fitted  and 
the  adjacent  one  (see  Fig.  288) ;  this  is  to  enable 
the  nut  to  be  turned  without  difficulty.  It  is, 
therefore,  important  to  decide  first  the  medio- 
lingual  angle  of  the  band  ;  this  having  been  done, 
the  other  angles  and  surfaces  are  fixed  according 
to  the  jjarticular  requirements  of  the  tooth  being 
operated  upon.  The  cervical  edge  of  the  band 
must  not  be  cut,  but  drawn  in,  so  that  when 
the  band  is  clamped  it  will  accurately  fit  the 
neck  of  the  tooth ;  in  the  case  of  an  upper 
molar  this  contouring  is  approximately  the  same 
all  the  way  round  the  tooth,  but  with  a  lower 
molar  the  contouring  is  only  necessary  medially, 
distally,  and  lingually ;  buccally  the  tooth  pre- 
sents a  very  convex  surface  right  down  to  its 
neck,  and  it  is  often  advantageous  to  stretch  the 
cervical  edge  of  the  band  in  this  region  (the  Peeso 
stretching  pliers  (see  Fig.  697)  may  be  used  for 
this  purpose).  It  is  also  well  to  contour  the 
occlusal  edge  of  the  band,  in  order  that  the  burn- 
ishing that  must  be  done  here  to  adapt  it  perfectly 
to  the  tooth  may  be  facilitated ;  the  degree  to 
which  this  is  done  is  determined  by  the  form  of 
tlie  individual  tooth,  the  buccal  surface  of  a 
lower  molar  requiring  the  greatest  amount  of 
"  puUmg  in  "',  and  this  is  another  reason  why  it 
is  advisable  to  stretch  the  cervical  edge  of  this 
part  of  the  band  for  a  lower  molar. 

The  tooth  having  been  perfectly  cleaned  on 
all  its  surfaces,  and  the  band  havmg  been  shaped 
and  the  two  edges  suitably  prepared,  it  is 
ready  to  be  fitted  to  the  tooth  (always  in  the 
mouth,  never  on  tlie  model) ;  it  shovild  be  well 
opened  so  that  the  constricted  cervical  jDortion 
may  easily  pass  the  greatest  diameter  of  the 
tooth  at  the  contact  points  on  both  sides  simul- 
taneously up  to  the  gum  margin  ;  the  band  may 
now  be  closed  slightly  to  allow  it  to  pass  between 
gum  and  tooth  without  ])ain  or  injury,  and  then 
pressed  on  till  the  occlusal  edge  of  the  band 
coincides  with  the  occlusal  surface  of  the  tooth. 
A  flattened  piece  of  wood  or  bone  of  the  size 
of  a  small  handle  of  a  tooth-brush,  or  the 
short  flat  end  of  a  metal  spatula,  is  well 
adapted  for  this  purpose ;  if  the  resistance  is 
too  great  for  want  of  separation,  the  Peeso 
pliers  may  be  used  to  force  the  band  past  the 


177 


contact  points.  On  the  distal  surface  it  should 
not  be  carried  quite  as  far  as  on  the  medial, 
thus  leaving  a  small  piece  of  the  band  to  be 
burnished  on  to  the  occlusal  surface,  which 
removes  any  liability  there  might  be  for  the 
band  to  slide  toA\ards  the  root  of  the  tooth,  and 
also  gives  the  front  end  of  the  tube  an  inclination 
towards  the  gum.  The  latter  object  is  desirable 
as  it  facilitates  the  adjust- 
ment of  the  bow. 

The  band  should  now 
be  burnished  to  conform 
accurately  to  the  tooth, 
startijig  in  the  centre  of 
the  buccal  surface,  and 
gradually  \\orking  round  to 
the  lingual,  and  tightenmg 
the  band  at  intervals  as  its 
conformation  is  improved. 
A  large  egg-shaped  burn- 
isher should  be  used  on  the 
buccal  and  lingual  surfaces  ; 
on  the  medial  and  distal 
surfaces  a  strong,  short,  flat 
instrument  is  more  suit- 
able, being  supjjlemented 
by  the  former.  The  j)ro- 
cedure  is  the  same  « liether 
the  buccal  tube  Ls  already 
attached  to  the  band  or 
not,  though  the  latter  is 
simpler  and  better,  the  ' 
tube  beuig  ultimately  sol- 
dered exactly  where  it  is 
needed. 

The  band  having  been 
firmly  clamjjed  on  the 
tooth,  the  surjilus  end  of 
the  threaded  -wiie  should 
not  be  cut  off,  as  a  general 
rule,  but  bent  to  lie  close 
against  the  Imgual  surface 
of  the  adjacent  tooth,  just 
above  the  gingival  margin 

Fio.  284.— Iiistriunenfc   (see  Fig.  288). 

de\ased  by  G.  North-       Position    of    the    Buccal 

croft.     One  end  is  to  Tube.— When   the    band   is 

augn    buccal    tubes   ,  ,  ,  ■/ 1        .  i  .    i 

and   the   other  is  a   bought      with      the      tube 

wrench.  already  attached  they  are 

united  at  their  centres ;  as 

the  t%\o  are  parallel  this  permits  of  such  bands 

being  used  for  any  tooth — right  or  left,  upper  or 

lower, — and  as  the  attachment  extends  over  a 

very  small  area  the  direction  of  the  tube  may 

be  adjusted  to  a  slight  extent,  for  individual 

teeth,  by  insertmg  into  it  an  instrument  which 

fits  it  accurately,  such  as  that  designed  by  G. 

Northcroft  (see  Fig.  284),  and  then  givmg  the 

tube   the   desired    direction   by   the   necessary 

movement  of  the  instrument. 

(1)  Medio-dislal   Position. — The  buccal   tube 


i 


should  be  soldered  to  the  band  so  that  when 
the  nut  on  the  bow  is  m  contact  with  its  medial 
end  it  wUl  be  opposite  the  inter-proximal  space 
between  the  banded  tooth  and  the  one  in  front. 
In  the  case  of  molar  bands,  the  centre  of  the 
tube  is  soldered  to  the  centre  of  the  buccal  side 
of  the  band  (see  Figs.  276,  277) ;  in  the  ease  of 
premolar  bands  a  portion  nearer  the  medial  end 
of  the  tube  must  be  attached  to  the  band  (see 
Fig.  279). 

(2)  Occlmo-cervical  Position. — The  tube  should 
be  at  the  centre  of  the  band  (see  Fig.  276),  or 
nearer  the  cervical  edge  «hen  practicable.  This 
is  often  essential  in  the  lo\\er  jaw  in  order  that 
the  tube  may  be  free  from  the  buccal  cusj)s  of 
the  corresponding  upper  teeth  when  the  teeth 
are  in  occlusion. 

(3)  Distance  from  the  Buccal  Surface  of  tJie 
Tooth. — If  the  banded  tooth  is  lingually  placed 
in  relation  to  the  tooth  in  front  of  it,  it  may  be 
necessary  to  bring  the  tube  further  out  buccally 
than  would  be  the  case  if  the  tube  were  soldered 
direct  to  the  band.  In  such  a  case  the  band 
should  be  thickened  by  suitable  pieces  of  metal, 
or  a  short  length  of  thick  platinum  wire  (see 
Fig.  279)  should  be  soldered  to  its  buccal  surface 
at  right  angles,  where  the  tube  is  usually  at- 
tached ;  the  tube  is  soldered  to  whichever  of 
these  additions  has  been  employed.  The  latter 
has  the  advantage  that  the  direction  of  the  tube 
can  be  easily  altered  by  means  of  a  suitable 
instrument — one  that  accurately  fits  the  tube. 

Direction  of  the  Buccal  Tube. — The  vertical 
direction  should  be  such  that  when  the  bow  is 
placed  m  the  tube  it  \\ill  pass  across  the  necks 
of  the  mcLsor  teeth  (or  other  desired  position) 
without  the  necessity  of  bending  the  bow.  (See 
p.  178.) 

The  horizontal  direction  should  be  such  that 
the  tubes  of  the  two  sides  are  parallel,  so  that 
the  bow  may  be  adjusted  to  them  without 
sharj)  bends  bemg  requued.  A  compromise 
bet\\een  these  two  requuements  will  probably 
have  to  be  made  in  most  cases.     (See  Fig.  288.) 

The  tubes  must  approximate  parallelism  with 
the  buccal  surfaces  of  the  teeth ;  otherwise  one 
end  wiU  project  buccally  and  probably  not 
be  tolerated  by  the  cheek.  The  distal  ends  of 
the  tubes  should  always  be  bevelled,  and  m 
some  cases  it  may  be  advisable  to  cut  away  so 
much  of  the  tube  on  its  buccal  aspect  that  the 
lumen  is  exposed. 

Having  fitted  the  bands,  without  tubes,  to 
the  teeth,  some  ojierators  now  take  an  im- 
pression, remove  the  bands  from  the  teeth,  and 
set  them  in  place  in  the  impression.  A  cast  is 
made,  and  the  tubes  are  soldered  to  the  bands, 
wHle  on  this ;  when  this  has  been  done  the 
bow  is  also  fitted  to  the  cast  before  the  bands 
are  taken  off. 

Cementation  of  the  Bands. — The  tooth  should 


178 


be  thoroughly  cleansed  by  meaiLS  of  powder 
and  brushes  or  tape  on  every  surface,  and  wiped 
over  with  hj^drogen  peroxide  and  well  syringed, 
so  as  to  remove  every  trace  of  debris  and  mucus. 
The  field  of  operation  should  now  be  protected 
from  moisture  by  the  use  of  fibre  lint  buccally 
and  a  cotton-wool  roll  Imgually,  assisted  by 
the  saliva  ejector;  the  tooth  should  be  dried 
thoroughly  and  wiped  with  chloroform,  which 
removes  any  remauiing  traces  of  mucus.  A 
hydraulic  oxj'-jjhosphate  cement  should  be 
used  to  cement  the  band,  as  it  is  not  always 
possible  to  ensure  absolute  dryness  of  the  tooth  ; 
havmg  been  thmly  mixed  a  sufficient  quantity 
is  placed  on  the  inner  surface  of  the  band — first  j 
applied  at  the  cervical  edge,  wlience  it  will  flow 
to  the  other  edge.  The  band  is  now  f)laced 
over  the  tooth,  and  its  cervical  edge  carried 
completely  home  by  a  thumb  or  finger  pressed 
over  its  occlusal  edge ;  this  procedure  will  ensure 
the  cement  being  carried  clown  on  the  tooth 
to  its  cervical  edge  along  with  the  band,  which 
is  now  clamped  on  the  tooth  by  tightening  the 
nut.  When  it  is  no  longer  possible  to  keep  the 
field  of  operation  dry,  the  patient  is  instructed 
to  rinse  with  hot  water  to  hasten  the  setting. 
When  hard  the  surplus  cement  is  removed, 
special  care  being  taken  to  clean  the  cervical 
margm. 

Lo^\e  Young  recommends  the  use  of  Evans' 
Orthodontical  Gutta-percha ;  the  tooth  need 
not  be  dry  and  there  is  no  fear  of  the  material 
being  washed  out. 

The  Adjustment  of  the  Bow. — The  next  step 
in  the  preparation  for  active  treatment  is  the 
proper  adjustment  of  the  wii-e  bow,  known  also 
as  the  expansion  bow,  alignment  bow,  etc. 
This  cannot  be  undertaken  till  the  position 
of  the  buccal  tubes  has  been  definitely  fixed. 
It  must  be  clearly  recognized  that  the  wire  bow 
is  the  frame  that  is  to  serve  as  the  mould  on 
which  to  re-form  the  irregular  dental  arch ;  the 
irregular  teeth  are  to  be  made  to  conform  to  its 
outline,  and  when  this  has  been  accomplished 
a  normal  dental  arch  should  be  the  result.  It 
is,  therefore,  of  the  utmost  importance  that 
this  wire  bow  should  be  adjusted  with  the 
greatest  care,  for  it  is  not  too  much  to  say  that 
it  is  possible  by  its  use  to  perform  any  combina- 
tion of  tooth  movements,  but  that  in  order  to 
bring  about  any  given  combination  of  move- 
ments it  must  be  manipulated  with  skill  and 
forethought.  The  first  step,  then,  in  the 
operation  is  the  correct  adjustment  of  the  wire 
bow  m  the  buccal  tubes  and  the  correct  shaping 
of  the  bow  throughout  the  remainder  of  its 
length. 

The  bow  is  fitted  by  first  securhig  a  basis 
from  which  to  work ;  this  is  done  by  placing 
only  one  end  of  the  bow  in  its  buccal  tube  and 
turning  the  corresponding  nut  to  engage  the 


medial  end  of  that  tube  ;  the  position  of  the 
nut  should  be  such  that  the  threaded  fiortions 
of  the  bow  shall  terminate  at  corresponding 
pomts  of  the  dental  arch  on  both  sides.  If 
the  end  of  the  bow  projects  a  considerable 
distance  beyond  the  end  of  the  tube,  it  should 
be  shortened  so  as  to  project  oidy  one-eighth  of 
an  inch ;  this  is  to  permit  of  subsequent  adjust- 
ment if  such  should  be  found  necessary,  and 
ultimate  shortenmg  so  that  its  end  shall  coincide 
■with  the  end  of  the  tube.  The  cut  end  should 
then  be  rounded  so  as  not  to  present  sharp 
edges  m  case  it  should  come  in  contact  with 
the  tissues.  On  one  side  the  end  of  the  bow 
should  be  notched  with  a  thin  stone  so  that  the 
right  and  left  sides  may  be  recognized  without 
trial ;  this  should  always  be  done  on  the  same 
side. 

Considerations  Affecting  the  Shape  of  the  Wire 
Bow. — As  has  already  been  stated,  the  wu-e  bow 
is  the  frame  to  \\hicli  the  normal  dental  arch  is 
to  be  built ;  it  must,  therefore,  be  given  the 
shape  of  the  normal  dental  arch.  Except  in 
a  few  cases,  this  is  impracticable  at  the  com- 
mencement of  treatment,  because  the  wire  bow 
would  be  so  far  away  from  the  dental  arch  that — • 

(a)  it  could  not  be  tolerated  by  the  lips  and 

cheeks ;  and 
(h)  its     efficiency     would     be     considerably 

impaired. 

Its  form,  then,  must  be  a  compromise  between 
the  normal  and  the  actual ;  it  must  be  close 
to  the  teeth,  so  that  the  ligatures  may  be  used  to 
the  greatest  advantage,  and  the  comfort  of  the 
soft  tissues  not  disturbed.  Durmg  the  course 
of  treatment  it  may  be  necessary  to  re-bend 
the  bow  as  the  teeth  move  out  to  it,  causing 
it  to  assume  the  outline  of  the  normal  arch  by 
stages. 

The  bow  in  use  is  adjustable  m  its  relation  to 
the  distance — 

(1)  between  the  incisors  and  molars; 

(2)  between  the  molars  and  second  premolars 

of  the  two  sides. 

But  as  regards  the  first  premolars  and  canines 
the  transverse  distance  between  these  is  deter- 
mined by  their  relation  to  the  bow ;  that  is  to 
say,  buccal  movement  of  these  teeth  can  only 
be  obtamed  by  having  bent  the  bow  to  a  suitable 
form  before  \\  iring  the  teeth  to  it."^  Wliercas  the 
relationship  of  the  wire  bow  to  the  incisors, 
and  to  the  molars  and  second  jsremolars,  can 
be  adjusted  by  means  of  the  nuts  on  the  threaded 
portion  of  the  bow,  and  by  means  of  the  spring, 
respectively,  without  any  re-bending;  the  re- 
lation of  the  bow  to  the  canines  and  first  pre- 
molars, on  the  other  hand,  can  only  be  varied 
by    re-bendmg    the    wire    bow.     Therefore,    if 

'  Except  when  a  divided  bow  is  used. 


179 


these  teeth  need  buccal  movement  to  the  same 
extent  as  the  remaming  teeth,  it  is  advisable 
to  allow  tlie  bow  to  stand  furtlier  away  from 
them  tlian  from  the  remainder.  It  will  be 
observed  that  the  position  of  the  bow  as  regards 
its  distance  from  the  teetli  is  now  being  con- 
sidered. The  proper  alignment  of  the  buccal  j 
tubes  should  have  given  it  the  correct  position, 
across  the  necks  of  the  teeth  and  close  to  I 
the  gum ;  if  the  bow  were  nearer  the  mcisal 
edges  the  hgatures  would  not  remain  on  the  ; 
teeth ;  if  it  w  ere  nearer  the  roots  of  the  teetli 
injury  would  be  done  to  the  soft  tissues  and 
pain  caused.  If  this  needs  correction  it  should 
be  done  now  by  changing  the  direction  of  the 
tubes  with  a  suitable  instrument,  or  by  bending 
the  bow,  or  by  both. 

Supposing   the   irregular   dental   arch   to   be 
composed  of  small  teeth  in  alignment,  which 


Fig.  285. — Plaiii  bow.      Adjusted  in  the  buccal  tubes 
for  expansion  of  the  molar  region. 

(o)  Incorrect  method  of  giving  spring  to  the  bow;  it 

causes  rotation  of  the  molar. 
(6)  Correct  method   of  giving  spring   to   tlie   bow   by 

bending  its  extremity  lingually  just  in   front   of 

the  nut. 
(c)  Shows  effect   of   (b)  on  direction   of  movement  of 

molar    (directly    outwards    without    rotation)    as 

compared  with  the  effects  of  (a). 

are  to  be  placed  in  a  larger  concentric  arch, 
the  wire  bow  should  be  bent  to  rest  across  tlie 
necks  of  the  teeth,  almost  in  contact  with  the 
second  premolar,  further  from  the  first  pre- 
molar, and  slightly  further  from  the  canine  on 
its  distal  surface ;  but  should  begui  to  approach 
tlie  median  line  of  the  mouth  as  it  nears  the 
medial  surface  of  the  canuie,  and  then  come 
almost  in  contact  with  the  lateral  and  central 
if  these  teeth  are  to  be  moved  forward  (buccally). 

Any  individual  irregularity  must  be  dealt 
with  as  it  occurs,  such  as  bending  the  bow 
round  an  outstanding  tooth,  and  then  makmg 
it  only  approximate  to  the  position  suggested 
above. 

The  bow  having  been  adjusted  by  repeated 
trials  to  all  the  teeth,  as  outlined,  it  is  ready  to 
be  bent  to  enter  the  other  buccal  tube,  and  the 
position  that  this  end  of  the    wire    bow  must 


assume  before  being  placed  therein  is  one  of 
parallelism  ui  both  the  horizontal  and  vertical 
planes  with  the  corresponding  tube  (the  other 
end  already  conforms  to  this  demand).  This 
having  been  done,  the  bow  is  removed  and 
made  to  enter  the  two  tubes  simultaneously, 
when  the  position  of  the  nuts  may  be  made 
exact,  and  the  ends  of  the  bow  made  to  coincide 
with  the  ends  of  the  tubes.  The  bow  is  now  a 
passive  instrument,  and  ready  to  be  converted 
into  a  positive  force  to  brmg  about  any  tooth 
movement  or  combination  of  tooth  movements. 
For  the  anchor  tooth  and  that  immediately 
medial  to  it,  this  is  accomplished  by  giving 
spring  to  the  bow,  that  is,  by  separating  the 
extremities.  This  having  been  done,  and 
the  bow  replaced  in  the  tubes,  the  distal  end 
of  the  wire  bow  M'ill  move  through  the  arc 
of  a  larger  circle  than  the  part  just  in  front 
of  the  buccal  tube,  as  the  connection  between 
the  wire  bow  and  the  anchor  molar  tooth  is 
more  or  less  rigid ;  the  result  is  to  rotate  the 
molar,  a  movement  to  be  avoided  as  a  rule. 
This  is  accomplished  by  bending  the  bow  on 
each  side,  just  in  front  of  the  nuts,  so  that  the 
termuial  portions  approach  more  nearly  to 
parallelism  (see  Fig.  285).  As  the  molars  ex- 
pand this  adjustment  may  be  repeated ;  it 
ensures  the  molars  moving  buccally  without 
any  rotation. 

ANCHORAGE. 

The  successful  practice  of  orthodontics  depends 
entirely  on  what  is  known  as  anchorage,  and 
on  its  use  to  the  greatest  advantage. 

Pullen  defines  it  as  "the  resistance  selected 
as  a  base  from  which  force  is  to  be  delivered 
for  the  movement  of  teeth  ",  and  as  "  a  study 
of  comparative  resistance  values  in  the  teeth 
and  dental  arches  "  (8). 

So-called  anchorage,  for  orthodontical  pur- 
poses, is  obtained  from  teeth  and  bone,  directly 
from  the  former,  mdirectly  from  the  latter,  and 
then  only  m  the  case  of  removable  appliances. 

To  facilitate  the  description  it  is  accepted  that 
each  tooth  has  a  certain  resistance  value,  this 
value  varying  m  the  different  teeth. 

Resistance  value  depends  on — 

(1)  Size  of  tooth,  i.  e.  size  of  the  root  of  the 

tooth  ; 

(2)  Length  and  number  of  roots ; 

(3)  Position  in  the  bone  and  arrangement  of 

surrounding  alveolus ; 

(4)  Age  of  patient ; 

(5)  The    adjacent   teeth    (if   any)    and   their 

relation  to  the  tooth  under  considera- 
tion ; 

(6)  The  direction  of  movement ; 

(7)  Occlusion. 


180 


For  example —      •      ' 

(1)  A  lateral  will  offer  less  resistance  than  a 
premolar ;  a  central  less  than  a  molar.  The 
canine  when  fuUy  developed  probably  offers 
more  resistance  than  any  other  tooth. 

(2)  Three  united  roots  will  offer  greater 
resistance  than  a  single  or  double  root,  all 
being  of  equal  size ;  one  long  root,  e.  g.  the 
upper  canine,  probably  offers  more  resist- 
ance than  a  first  upper  molar ;  a  lower  molar 
certauily  cannot  be  relied  on  in  moving  a 
lo\\er  canine  without  bemg  disjjlaced  itself. 
(See  p.  155.) 

(3)  A  lower  molar  usually  offers  greater  re- 
sistance to   buccal  movement  than    an  upper 


A.  Simple — the  resistance  of  the  anchorage 
to  the  foi-ce  of  reaction  is  so  much 
greater  than  the  resistance  of  the  tooth 
to  be  moved  that  little  movement  of 
the  anchor  tooth  (or  teeth)  occurs. 

Reciprocal — the  resistance  to  action  and 
reaction  is  less  unequal,  and  movement 
occurs  and  is  desired  at  both  points. 

Stationary — the  point  of  resistance  to  the 
force  of  reaction  is  fixed  (the  only  real 
anchorage). 


B 


C. 


Movement  by  inclination. 

Line    akowing    direction 
of    movement 


Movement  by  translation. 

i-ine  ahourinff    dircction 
of"    rnoircment  ■ 


<CD/ 


Fig.  286. 


The  effect  obtained  by  using  a  round 
buccal  tube  is  shown  by  the  dotted 
lines. 

Variation  in  relation  between  bow  and 
tube  is  shown  by  tlie  linos,  which 
in  both  instances  pass  tlirough  the 
same  points.     (Dental  Record.) 


molar,  on   account  of   the  greater   quantity  of 
bone  on  its  buccal  surface. 

(4)  (a)  The  greater  the  age  of  the  patient  the 
greater  is  the  resistance  offered  by  surrounding 
bone  to  movement. 

(b)  During  the  period  of  root-formation,  a 
tooth  will  offer  less  resistance  in  proportion  to 
the  length  of  root  uncalcified. 

(5)  Distal  movement  of  a  second  premolar 
requires  much  less  force  if  there  is  no  first 
molar  behind  it  than  if  one  is  present ;  a  second 
premolar  held  lingually  by  tlie  approximation  of 
the  fir.st  premolar  and  first  molar  (so  reducing  its 
space),  wiU  offer  considerably  more  resistance 
than  if  the  normal  space  exists  for  it. 

(6)  Buccal  movement  of  an  incisor  offers  less 
resistance  than  distal  movement  of  a  premolar, 
apart  from  other  essential  factors. 

(7)  Rotation  offers  the  greatest  resistance  of 
any  movement. 

Anchorage  may  be  divided  into  three  main 
classes — 


A.  Simple  Anchorage  may  be  obtained  in  the 
following  ways — 

(a)  The  Simplest  Anclwrage. — A  larger  and 
stronger  tootli,  a  tooth  with  a  high  resistance 
value,  is  used  in  moving  a 
smaller  and  weaker  tooth, 
one  with  a  low  resistance 
value. 

Anchorage  is  usually  more 
complicated  than  this  form. 
(6)  Beinforced  Anchorage. 
Two  or  more  teeth  are 
united  to  give  increased 
resistance  value  in  moving 
one  or  more  teeth  of  less 
total  resistance  value  (see 
Fig.  288). 

(c)  Resistance  to  Trans- 
lation.— Tooth  movement  as 
usually  carried  out  is  by 
inclination  of  the  tooth 
rather  than  by  translational 
movement,  as  considerably 
less  force  is  required  to  bring 
about  the  former.  Therefore, 
if  the  appliances  are  so 
arranged  that  only  trans- 
lational movement  of  any  tooth  is  possible,  the 
resistance  value  of  that  tooth  will  be  considerably 
increased  (see  Fig.  286). 

In  all  tliese  instances  the  anchor  teeth  and 
the  teeth  to  be  moved  may  be,  but  usually  are 
not,  in  opposite  jaws,  or  the  lower  jaw  itself 
may  be  the  part  to  be  moved.  Attachments 
between  the  two  jaws  are  described  as  "  uiter- 
maxUlary  ".     (See  Figs.  290,  297,  312,  313.) 

B.  Reciprocal  Anchorage. — AU  anchorage  is 
really  reciprocal,  but  the  term  is  usually  em- 
ployed to  denote  intentional  movement  at  both 
points  of  apjDlication  of  the  force,  the  resistances 
not  being  .so  unequal  as  to  permit  perceptible 
movement  at  one  point  only  (see  Fig.  287,  1). 
As  with  simple  anchorage,  it  may  be  in  its 
simplest  form  ^hen  used  to  move  two  teeth 
towards  (see  Fig.  330,  a)  or  away  from  one 
another,  as  in  moving  two  centrals  medially  or 
in  moving  the  molars  buccally ;  or  the  resist- 
ance at  either  pomt  of  application  may  be 
reinforced. 


The  effect  obtained  by  using  an  oval 
buccal  tube  is  shown  by  the 
dotted  lines. 

Variation  in  relation  between  bow 
and  tube  is  seen  to  be  impossible. 
For  it  to  be  possible  for  the 
molar  to  move  by  inclination, 
it  would  be  necessary  for  the 
bent  bow  wire  to  twist.  [Dental 
Record.) 


181 


The  teeth  to  be  moved  may  be  iii  the  same 
jaw,  or  in  opposite  jaws,  when  the  force  is  an 
inter-maxillary  one. 

C.  Stationary  (Occipital)  Anchorage. — The  occi- 
put and  associated  skull  bones  are  the  point  of 
resistance,  and  provide  an  absolutely  stationary 
anchorage.     (See  Fig.  328.) 

TOOTH    MOVEMENT 

Possible  Movements  of  the  Teeth  and  Lower 
Jaw. — The  possible  movements  that  any 
tooth  may  undergo  are  seven,  they  are — 

(1)  Buccal, 

(2)  Lmgual, 

(3)  Distal, 

(4)  Medial, 

(5)  Depression, 

(6)  Elongation, 

(7)  Rotation.     (See  Fig.  287.) 

Angle  has  described  this  in  other  words. 
He  refers  to  it  as  the  seven  positions  of 
malocclusion  that  any  tooth  may  occupy, 
namely— 


2.  Control  by  the  patient.     Very  undesirable 

in    some    cases  but   most    valuable    in 
others. 

3.  Comfort  of  the  patient. 

4.  Whether  individual  control  of  every  tooth 

is  necessary. 


(1)  Lingual, 

(2)  Buccal, 

(3)  Medial, 

(4)  Distal, 

(5)  Supra-, 

(6)  Infra-, 

(7)  Torso-; 

and  to  brhig  them  mto  normal  occlusion 
they  have  to  be  moved  m  the  direction 
opposite  to  that  which  the  name  of  their 
position  of  malocclusion  would  imply. 

The  possible  movements  of  the  lower 
jaw  are  medial,  distal,  and  lateral, 

A  description  of  how  these  various 
movements  may  be  accomplished,  alone 
or  in  combination,  by  means  of  apparatus, 
fixed  or  removable,  \\ill  now  be  under- 
taken. The  problem  of  anchorage  is 
inseparably  connected  with  this,  for,  as 
has  been  explained,  the  same  force  may 
be  used  to  produce  a  certain  movement 
in  one  tooth  and  the  opposite  movement 
in  another  tooth. 

The  choice  of  an  appliance  to  bring 
about  the  necessary  movements  in  any 
given  case  has  now  to  be  settled.  The 
advantages  and  disadvantages  of  fixed 
removable  appliances  have  been  summarized 
on  p.  170.  The  following  points  are  among 
the  most  important  to  be  considered  : — 


Efficiency,  including  the  range  of  efficiency 
(with  fixed  appliances,  each  tooth  may 
be  under  sejjarate  control),  and  the  cer- 
tainty of  obtaining  residts. 


Fig.  287. — Shows  the  principle  of  tix^d  apphances  as  exemplified 
by  the  wire  bow  and  clamp-bands,  and  the  movements 
teeth  may  undergo. 

1.  Buccal  movement  of  first  molars  and  second  premolars  by 
the  spring  of  the  bow  (reciprocal  anchorage). 

2.  Labial  movement  of  the  incisors  by  the  spring  of  the  bow, 
which  is  developed  by  increasing  its  length  between  the 
ligatures, 

3.  and  the  nut  on  the  bow.  This  arrangement  of  the  appliances 
is  also  described  as,  in  effect,  a  jack-screw,  which  is  not 
strictly  accurate  unless  the  bow  is  rigid. 

4.  Ligatm-e  to  rotate  the  left  central,  which  is  also  being  moved 
distally  by  the  spui-  on  the  bow. 

5.  Rubber  wedge  between  the  bow  and  right  canine  to  move 
the  latter  liugually. 

(a)  Ligature  and  spur  to  move  the  left  lateral  distally 
and  labially. 

(b)  Ligature  to  move  the  left  canine  buccally. 

(c)  Spur   on   a   plain   band   on   the  left  canine  to  hold 
the  ligature  in  position  near  the  neck  of  this  tooth. 

{d)  Shows    where    the    bow  would  be  at  rest  when  an 
incisor  is  to  be  elongated. 

(e)   Shows  the  position  of  the  bow  after  application  of 
the  ligature. 

{g)  and  (/)  show  the  same  when  a  tooth  is  to  be  depressed. 

{h)  and  {k)  show  a  ligature  with  crib  on  a  premolar;  the 
crib  prevents  the  ligature  slipping  towards  the  root  of  the 
tootli,  where  it  would  injure  the  soft  tissues. 
1    and  2  are  examples  of  buccal  movement,  tlie  incisors  antl 
molars  being  in  lingual  occlusion ; 

4  of  rotation,  the  left  central  being  in  torso-occlusion; 

5  of  lingual  movement,  the  canine  being  in  buccal  occlusion ; 
4  and  (a)  of  distal  movement,  the  left  central  and  lateral  being 

in  medial  occlusion. 
{d)  of  elongation;  and 
(/)  of  depression. 

and  5.  The  amount  of  time  the  patient  can  give 

the  operator. 

6.  Aesthetics   and    speech    may   have   to    be 
considered  m  a  few  cases. 

7.  The  hygiene  of  the  moutli  must  not  be 
overlooked. 


The  relative  advantages  and  disadvantages 
of  the  two  classes  of  appliances  having  been 


182 


Direction  ot  Movement. 


A.  Buccal,  Upper 
or  Lower. 


B.  Lingual,  Upper 
or  Lower. 


MAJOR  TOOTH  MOVEMENTS. 
I.— Molars,  Premolars,  and  Canines. 

TeeVi  to  be  moieil. 


C.  Medial. 


D.  Distal. 


E.  Depression. 

F.  Elongation. 

G.  Rotation     . 


(i)  Molars  and  Second  Premolars, 
(ii)  First  Premolars  and  Canines, 
(i)  Molars  and  Second  Premolars. 
(ii)   First  Premolars  and  Canines. 


I 


Upper.     Collective  movement  is 

not  needed. 
Lower.     The  jaw  itself  is  moved 

forward. 

Upper  and  Lower. 

(i)  Molars  and  Second  Premolars. 


(ii)  First  Premolars  and  Canines. 


Unilateral  or  Bilateral. 
I  On  both  sides. 
I  On  one  side  only. 
I  On  both  sides. 

On  one  side  only, 
j  On  both  sides. 

On  one  side  only. 

{On  both  sides. 
On  one  side  only. 
(On  both  sides. 
On  one  side  only. 
j  On  both  sides. 
I  On  one  side  only. 
[  On  both  sides, 
j  On  one  side  only. 


Nature  of  Appliance. 

I    1.  Fixed. 

\   2.  Removable. 

(    3.  Fixed. 

\   4.  Removable. 

(    5.  Fixed. 

\  6.  Removable. 

j    7.  Fixed. 

\  8.  Removable. 

f   9.  Fixed. 

(  10.  Removable,  upper  only. 

111.   Fixed. 

\12.  Removable,  upper  only. 

(13.   Fixed. 

(  14.  Removable. 

I  15.  Fixed. 

\16.  Removable. 

fl7.  Fixed.  ~j 

\18.  Removable.  [Lower 

(  19.  Fixed.  |  only. 

'\20.  Removable.; 

(21.  Fixed. 

\22.  Removable. 

(23.  Fixed. 

( 24.  Removable. 

/25.   Fixed. 

(26.  Removable. 

I  27.  Fixed. 

\28.  Removable. 


1      29.  When  collective  movement  of  all  at  same  time 


Lower.  ,      ^^.    ,,„^,„ 

(iii)  Molars  and  Second  Premolars,  ,-  j^  needed,  lower  jaw  is  moved  distally. 
First  Premolars  and  Canines.  J  ^^    Fixed 

{(i)  In  both  jaws.  y^{  Removable. 

f32.  Fixed, 
(ii)  In  one  jaw.  jgg    Removable. 

r  ,      ,    .  (34.   Fixed, 

(i)  In  both  jaws.  J35    Removable. 

-  .  f36.  Fixed. 

I  (ii)  In  one  jaw.  \ 37.  Removable. 

Only  possible  as  individual  movement. 


n. — Incisors. 


Direction  of  Movement. 

A.  Buccal    . 

B.  Lingual  . 


C.  Medial,    Upper 
and  Lower. 

D.  Distal,    Upper 
and  Lower 


Teeth  la  be  moved. 

(  Upper  and  Lower. 

\      Centrals  and  Laterals. 

(  Upper  and  Lower. 

\     Centrals  and  Laterals. 


V  Centrals  and  Laterals. 


E.  Depression 

F.  Elongation 

G.  Rotation  . 


f  Centrals  and  Laterals. 
I  Centrals  and  Laterals, 
[centrals  and  Laterals. 
I  Centrals  and  Laterals. 
Two  Incisors. 


f  These  two  movements 
are  exactly  similar 
and,  if  collective,  i.e. 
all  four  teeth  moving 
in  the  same  direction, 
would  be  medial  on 
one  side  of  the  me- 
dian line  and  distal 
on  the  other. 

j  In  both  jaws. 
In  one  jaw. 


/38. 
\39. 
f40. 
\41. 


Nature  of  Appliance. 

Fi.xed. 
Removable. 
Fixed. 
Removable. 


In  both  jaws. 
I  In  one  jaw. 
Contiguous  teeth. 


(44. 
\45. 
(40- 
"1 47, 
(48. 
\49. 
(50. 
\51, 
(52. 
\53. 


Fixed. 
Removable. 


Fixed. 

Removable. 

Fixed. 

Removable. 

Fixed. 

Removable. 

Fixed. 

Removable. 

Fixed. 

Removable. 


183 


■neighed,  it  Mill  be  seen  that  the  balance  I 
descends  on  the  side  of  advantage  with  the 
fixed  appliance* — were  there  no  other  favouring 
argument  ''greatest  efficiency"  would  suffice 
to  bring  this  about.  But  at  the  same  time  it 
must  not  be  forgotten  that  there  are  many 
opportunities  for  removable  appliances  to  do 
valuable  \\ork  where  the  use  of  fixed  appliances 
would  be  impossible.  As  an  example,  the  ca.se 
of  children  at  school  may  be  quoted ;  such  , 
patients,  if  at  all  intelligent,  will  manipulate  an 
expansion  plate  satisfactorily — its  active  opera- 
tion may  cease  at  any  stated  time,  and  the  plate 
act  as  a  retainer  tOl  the  dentist  has  an  oppor- 
tunity- of  examining  the  case  and  prescribing 
further  treatment. 

Before  beginning  any  tooth  movement,  it 
should  always  be  observed  that  such  a  move- 
ment is  not  prevented  by  the  position  of  other 
teeth ;  for  instance,  it  would  be  useless  to 
attempt  to  move  a  lingually  placed  lateral  into 
its  normal  position  if  the  space  between  the 
central  and  canine  is  not  sulficient  and  steps 
are  not  taken  to  make  it  sufficient ;  or  again, 
it  •would  be  of  no  avail  to  push  back  two 
upper  centrals  when  the  incisal  edges  of  the 
corresponding  lo^^'e^  teeth  are  in  contact  with 
them  at  or  near  their  cervical  edges ;  either 
the  vertical  relation  of  the  upper  and  lo^^•er 
incisors  must  be  corrected  first,  or  sjjecial  pre- 
paration made  so  that  the  movement  may  be 
possible  and  the  relationship  corrected  later, 
in  this  case  also,  notice  must  be  taken  that  the 
laterals  are  not  so  close  to  one  another  that  the 
space  between  them  is  insufficient  for  the  two 
centrals. 

The  movements  of  teeth  have  been  divided 
into  two  groups : 

(1)  Major  Tooth  ^Movements,  in  which  several 
teeth  are  moved  in  the  same  direction;  and — 

(2)  Minor  Tooth  Movements,  in  which  group 
the  movement  of  teeth  individually  is  dealt 
with. 

The  major  tooth  movements  are  classified 
in  the  table  on  p.  182.  The  numbers  in  the  last 
column  refer  to  the  -paragraphs  in  ichich  the  par- 
ticular movements  are  dealt  with. 

MAJOR    TOOTH    MOVEMENTS 

I.— MOLARS,  PREMOLARS,  AND  CANINES 

A.  Buccal  Movement :   Upper  or  Lower 

(i)  Molars  and  iSecond  Premolars  {on  both  sides) 

1.  Fixed  Appliances. 

Anchorage :  Reciprocal,  Reinforced. — The  ap- 
pliances being  in  position,  as  described  on  pp. 
176-179,  the  bow  is  removed  and  the  ends 
are  separated  by  a  pulling  movement,  so  that 
they  have  to  be  pinched  together  between  the 
thumb  and  finger  to  insert  them  in  the  buccal 


tubes.  The  bow  has  now  been  given  spring, 
and  its  tendency  is  to  resume  the  shape  given 
it  by  separating  its  ends,  and  thus  to  move 
the  molars  out  in  a  buccal  direction.  In  sepa- 
rating the  ends  they  are  only  to  be  pulled 
apart,  without  giving  any  definite  bend  to  the 
bow.  (See  p.  179.)  The  amount  of  this  separ- 
ation depends  on  the  extent  of  the  desired 
movement,  and  on  whether  the  bow  is  platinized 
gold  or  German  silver,  the  latter  requiring 
more,  especially  after  it  has  been  in  use  for  some 
time.  If  the  clamp-band  has  been  properly 
adjusted  its  threaded  wire  extends  to  the  lingual 
surface  of  an  adjacent  tooth — whether  it  is  the 
medial  or  distal  one  does  not  matter,  though 
usually  it  is  the  former,  and  as  the  molar  moves 
outward  this  adjacent  tooth  will  be  carried 
buccally  also,  through  the  medium  of  the  lingual 
wire.     "(See  Fig.  287.) 

When  the  second  deciduous  molars  are  in 
position  these  should  be  made  the  anchor  teeth, 
and  extensions  carried  from  the  bands  to  engage 
the  adjacent  teeth,  one  on  each  side,  so  that  they 
may  be  included  in  any  buccal  movement 
without  the  use  of  ligatures. 

As  the  wire  bow  widens  it  becomes  propor- 
tionally shorter  (see  Fig.  306) ;  the  nuts,  there- 
fore, must  be  turned  backwards  to  make  it 
longer,  or  it  would  come  in  contact  with  the 
incisors  and  force  them  lingually. 

2.  Removable  Appliances. — By  separating 
the  two  halves  of  a  split  plate,  either  by  turning 
a  screw,  opening  a  spring,  or  operating  a  device 
that  has  the  .same  effect.  The  first  premolars 
and  canines  can  well  be  included  in  this  move- 
ment. (See  Fig.  274.)  The  direct  action  of  the 
force  should  be  opposite  those  teeth  that  have 
to  be  moved  most,  or  the  screw  should  be  in 
such  a  position  that  the  force  will  be  distributed 
as  desired.  Two  or  more  teeth  should  have  plat- 
inized gold  wire  clasps  to  increase  the  stability 
of  the  plate  (the  wires  can  usually  be  arranged 
free  of  the  bite) ;  for  this  purpose  preference 
should  be  given  to  the  first  molars  (distal  sur- 
face), and  first  premolars  (medial  surface),  un- 
less any  deciduous  teeth  are  present,  when  they 
should  certainly  be  selected  ;  the  wires  should  be 
carefully  fitted,  especially  \\here  they  pass  over 
the  contact  points,  so  as  not  to  interfere  with 
the  bite.     (See  p.  171.) 

(ii)  First  Premolars  and  Canines  (on  both  sides). 
5.  Fixed  Appliances. 

Anchorage  :  Simple  and  Reciprocal. — This  is 
readily  done  by  ligaturing  these  teeth  to  the 
bow,  which  must  be  a  short  distance  away 
from  them.  If,  when  these  teeth  are  m  contact 
with  the  bow,  they  are  not  ^\■ide  enough,  the 
bow  must  be  removed  and  bent,  so  as  to  enable 
them  to  be  moved  further.  All  the  precautions 
mentioned  on  p.  179  must  be  observed. 


184 


6.  Removable  Appliances. — By  extending 
the  plate  referred  to  in  paragraph  2  to  reach  to 
the  lingual  surfaces  of  these  teeth.  If  all  the 
teeth  from  first  molar  to  canine  are  to  be 
moved,  the  application  of  the  force  should  be 
between  the  first  and  second  premolars.  (See 
Fig.  274.) 

In  the  lower  jaw  clasps  are  not  essential, 
but  a  cleat  should  be  fixed  in  the  plate  to  engage 
the  lingual  sulcus  of  the  first  molar  on  each  side, 
to  prevent  the  plate  sinking  into  the  soft  tissues. 
(See  Fig.  275.)  The  movement  of  the  molars 
will  be  less  satLsfactory  than  in  the  upper  jaw ; 
the  plate  should  therefore  be  made  as  rigid  as 


® 


Fig.  2S8. — Upper  bi'w  arranged  to  expand  the  arch  on  the 
right  side  only ;  the  left  side  is  vised  as  anchorage,  the 
source  of  which  is  the  molar,  premolars,  and  canine,  the 
first  of  these  through  its  clamp-band  with  oval  buccal 
tube,  which  permits  only  translational  movement,  and 
the  remainder  through  ligatures;  the  bow  is  bent  to 
rest  quite  close  to  these  teeth.  On  the  right  side  tlie 
molar  moves  by  inclination,  the  medium  of  attachment 
to  the  bow  being  a  round  buccal  tube,  which  permits 
of  this  type  of  movement;  when  the  molar  is  in  its 
correct  position,  the  remaining  teeth  are  ligatured  to 
the  bow  and  brought  to  their  positions  one  by  one. 

(o)  Roimd  tube  in  section. 

(b)  Oval  tube  in  section. 


possible;  even  then  it  may  be  necessary  to 
resort  to  a  fixed  appliance  if  considerable 
expansion  is  desired. 

(i)  and  (ii)  Molars,  Premolars,  and  Canines,  on 
one  side  only. 

3  and  7.    Fixed  Appliances. 

Anchorage :  Simple  Bein forced,  and  Resistance 
to  Translation. — Three  or  four  teeth  (first  molar 
to  canine)  of  one  side  are  used  in  moving  one 
on  the  abnormal  side.  (See  Fig.  288.)  The 
bow  is  fitted  in  contact  with  the  teeth  and 
given  spring ;  the  teeth  of  the  normal  side  are 
all  ligatured  to  it,  and  the  force  is  exerted  on 
one  tooth  at  a  time  on  the  abnormal  side — 
on  the  molar  through  the  clamp-band;  when 
that  tooth  is  correctly  placed,  force  is  exerted 


on  the  premolars  and  canine  by  successive 
ligatures  until  they  are  all  pulled  out  to  their 
normal  positions.  Four  teeth  are  used  in 
moving  four,  but  only  one  at  a  time  is  moved, 
and  in  each  case  all  the  other  four  are  used  to 
accomplish  this. 

The  same  result  is  obtained  by  banding  the 
canine  and  soldering  a  lingual  wire  from  it  to 
the  end  of  the  screw  of  the  clamp-band  and 
laying  it  close  against  the  two  premolars ;  it  is 
advisable  to  ligature    the  canine  to  the  bow, 
the  lingual  wire  being  mcluded.     (See  Fig.  289.) 
This  ofi'ers  a  more  stable  anchorage  than  the 
first  method ;    the  anchorage  can  be  rendered 
still  more  stable  by  the  use  of  an  oval  (see 
Fig.  288,  b)  or  other  tube,  which  permits  of 
translational  movement  only,  on  the  molar. 
The  resistance  of  the  anchorage  and  the 
movement  of  the  teeth  may  be  augmented 
by   the    use    of    inter-maxUlary   ligatures. 
Supposmg  the   first  right   upper   molar   is 
the  tooth  to  be  moved  buccally,  a  hook  or 
spur  is  soldered  on  the    buccal  surface  of 
the  left  (anclior)  vipper  molar,  and  another 
to  the  corresponding  left  lower  molar,  .but 
on  the  lingual  surface ;  an  inter-maxillary 
iTibber   band  is    fixed    on   the   two    spurs. 
The  tendency   then  is   for  the  left   upper 
molar   to  be  pulled  lingually,   so  counter- 
acting any  liability  for  it  to  be  displaced 
buccally,    due    to    insufiicient    stability    to 
withstand  the  force  e.xerted   on  it  by  the 
spring    of    the    wire    bow.     SimOarly,    the 
buccal  movement  of  tlie  right  upper  molar 
may  be  assisted  by  a  rubber  band  passmg 
from  its  lingual  surface  to  the  buccal  surface 
of  the  corresponding  lower  molar  (12,  p.  105). 
(See  Fig.  290.) 

The  lower  bow  should  be  passive  and 
all  the  lower  teeth  ligatured  to  it,  so  that 
little  or  no  movement  of  the  lower  teeth  is 
possible. 

4  and  8.  Removable  Appliances. — The 
necessary  appliance  is  a  plate  designed  for 
expansion  of  the  dental  arch.  The  application 
of  force  should  be  as  nearly  directly  opposite 
the  tooth  to  be  moved  as  practicable ;  the 
plate  should  fit  well  round  this  tooth,  and 
around  the  neck  of  another  on  tlie  same  side 
as  far  away  as  possible,  but  be  cut  away  from 
the  other  teeth.  The  tooth  on  which  tlie  force 
is  acting  directly  will  move  most,  though  the 
other  may  also  move. 

It  may  be  possible  to  move  the  remaining 
teeth  by  widening  the  plate  to  come  into  contact 
with  them,  at  the  same  time  cuttuig  it  away 
from  the  tooth  tliat  lias  already  been  moved ; 
this  should  be  done  by  degrees,  to  obviate  the 
possibility  of  a  relapse  of  the  latter,  the  plate 
and  tooth  first  moved  bemg  kept  only  just 
out  of  contact  with   one   another.     The  same 


185 


principle  would  be  followed  if  a  new  plate  had 
to  be  made. 

With  a  simple  non-expansion  plate,  a  powerful 
wire  spring,  in  the  case  of  a  molar,  should  be 
used  at  the  neck  of  the  tooth,  from  which  the 
plate  is  cut  aw  ay ;  a  band  with  a  spur  to  hold 
the  spring  in  place  on  the  tooth  is  usually 
necessary  (see  Fig.  291).  If  it  has  been  possible 
to  fix  another  spring  hi  the  plate  at  the  same 
time,  the  first  one  may  now  be  used  passively 
as  a  retauier,  and  the  second  one  brought  mto 
use,  the  plate  bemg  cut  away  from  the  neck  of 
the  tootli  to  be  moved  and  the  sprhig  made  to 
act  at  the  gum  margin  ;  otherwise  a  new  plate 
must  be  made  on  the  same  principle,  but  in 
addition  it  must  retain  the  tooth  (or  teeth) 
already  moved  by  fitting  it  closely. 

Small  screws  set  in  the  \mlcanite  (see  Fig. 
291),  thickened  for  the  purpose,  may  be  used 
to  move  the  two  premolars  individually  and 
one  at  a  time.  The  end  of  each  screw  should 
have  a  piece  of  metal  attached  to  it,  that  it 
may  the  better  engage  the  tooth.  A  nut  may 
be  vulcanized  in  the  plate  to  receive  the  screw, 
whose  pitch  should  be  very  small,  so  that 
movement  may  be  gradual ;  the  end  of  the 
screw  should  be  nicked  for  turning  with  a 
screw-driver,  or  made  square  in  section  for 
turning  with  a  watch-key. 

B.  Lingual  Movement :  Upper  or  Lower 

(i)  First  Molars  and  Second  Premolars. 

On  hoik  sides.  This  movement  is  rarely 
needed. 

9.  Fixed  Appliances. — Lowe  Young  (12,  p. 
112)  says  this  may  be  accomplished  by  bring- 


be  soldered  to  the  bow  in  front  of  the  nut 
on  each  side,  and  a  rubber  band  brought  from 
it  to  the  back  of  the  buccal  tube,  to  hold  the 
bow  in  the  tubes.     (See  Fig.  292.) 

10.  Removable    Appliances. — With    these 
this  movement  is  only  practicable  in  the  case 


Fig.  289. — Shows  aiiotlicr  method  of  obtaining  movement  of  one 
molar  only.  An  oval  tube  on  the  right  side  would  increase 
the  anchorage.      (Dental  Record.) 

ing  ui  the  ends  of  the  bow  towards  one  another 
after  it  has  been  adjusted  so  that  the  ends 
have  to  be  opened  before  the  bow  can  be  fitted 
in  the  buccal  tubes.  With  such  a  spring  the 
tendency  is  for  the  bow  to  come  forward;  to 
obviate  this,  a  spur,  pointing  forwards,  should 


Fig.  290. — Arrangement  of  inter-maxillarj'  force  for 
reciprocal  movement  of  upper  molar  buccaUy 
and  lower  molar  lingually,  unless  the  anchorage 
is  arranged  to  prevent  movement  of  either  one 
of  the  teeth. 


of  the  upper  jaw.  It  might  be  attempted  by 
making  a  plate  whose  screw  is  already  opened ; 
when  the  plate  is  divided  a  piece  of  it  should 
be  entirely  removed,  its  size  varying  according 
to  the  extent  of  movement  desired.  Complete 
cribs  should  be  attached  to  the  first  premolar 
and  first  molar,  these  bemg  united  by 
a  buccal  wire  passing  across  the  second 
premolar;  in  cases  where  little  force 
is  necessary,  a  complete  crib  on  the 
second  premolar  with  medial  and 
distal  extensions  to  engage  the  neck 
of  the  first  premolar  and  first  molar 
woidd  probably  suffice.  Lingual  move- 
ment of  the  teeth  on  both  sides  is 
obtained  by  gradually  closing  the 
screw. 


On  one  side  only. 

11.  Fixed  Appliances. — Anchorage: 

Simple.     This  is   accomplished  by   a 

reversal  of  the  appliances  and  tlieir 

use  as  described  under  paragraph  3. 

The    bow    should    be    given    Ihigual 

spring,  and   the  teeth    on    the  side   not  to  be 

moved    ligatured    to    it,    and    the    spurs    and 

rubber   bands    arranged    to    pull    inwards  tlie 

molar  that  is   in  buccal  occlusion ;  the   second 

premolar  may  be  ligatured  to  the  lingual  screw 

of  the   molar    clamp-band    if    it   is  desked  to 


186 


move  tliLs  tooth  lingiially  at  the  same  time, 
providing  the  anchorage  will  suffice ;  the  spur 
should  then  be  at  the  medio-biiccal  corner  of 
the  molar  that  is  being  moved. 

12.  Removable     Appliances. — This     is      a 

difficult  movement  with  a  removable  appliance, 

e 


3  ■!■ 

Fig.  291. — Removable  appliance  to  move  a  molar  and  premolars  buccally 
— one  at  a  time  so  as  not  to  strain  the  anchorage. 

1.  Vulcanite  plate. 

2.  Wire  clasp. 

3.  Plain  band  witli 

4.  a  spur  to  hold 

5.  a  coil  spring  in  position  on  the  tooth. 

6.  Screws  in  the  vulcanite  to  move  the  premolars  bnccally. 
(a)  and  (c)  Cross-sections  of  6. 

6.  A  nut  with  tags  to  hold  it  in  the  vulcanite. 

7.  A  screw  to  work  in  6  and  move  the  premolar. 

8.  Enlarged  metal  end  soldered  to  7  to  increase  the  contact  with 

the  tooth. 
(6)  Cross-section  of  plain  band  on  the  molar. 

owing  to  the  unstable  anchorage.     The  plate 
should  be  cla.sped  to  the  teeth  at  two  or  three 
pomts,  and  a  hook  set  in  the  vault  of  the  plate 
opposite  the  teeth  to  be  moved.     The  molar 
or  premolar   must  be  banded,  and  have  a 
buccal    spur    to    engage    the    other    tooth ; 
lingually   there   must    be    a    spur    directed 
occlusally  to  engage  a  rubber  band,  which 
also  engages  the  spur  in  the  plate ;  by  this 
means  these  teeth  may  be  moved  lingually, 
the  plate  having  been  cut  away  from  them. 
This  method  is  not  applicable  to  the  lower  jaw. 

(ii)  First  Premolars  and  Canines. 

On  both  sides. 

13.  Fixed  Appliance.s. — A  difficult  move- 
ment unless  associated  with  buccal  move- 
ment of  the  approximal  teeth ;  it  will  be 
further  considered  under  "Individual  Tooth 
Movements  ".     (See  pp.  207  and  211.) 

14.  Removable  Appliances. — With  re- 
movable appliances  this  may  be  accomplished 
in  either  jaw  by  banding  one  of  the  teeth  and 
carrying  a  buccal  spur  to  the  other  tooth  to 
be  moved.  A  lingual  spur  directed  occlusally 
is  soldered  to  the  band,  from  which  a  rubber 
band  stretches  to  a  hook  on  the  lingual  or  palatal 
surface  of  the  plate,  so  situated  that  the  band 


pulls  in  the  required  direction.  The  plate  must 
be  securely  held  by  wire  clasps.  If  the  first  molar 
and  second  premolar  have  been  previously 
pulled  m  a  lingual  direction,  they  must  be 
retained  by  this  second  plate,  which  is  also  to 
move  the  first  premolar  and  canine. 

One  side  only. 

15.  Fixed  Appliances. — The 
same  as  for  individual  movement 
(see  pp.  207  and  211). 

16.  Removable  Appliances. 
As  in  paragraph  14,  but  on  one 
side  only. 

C.  Medial  Movement :   The  Lower 
Jaw 

Post-normal  occlusion  of  the 
lower  jaw  is  frequently  associ- 
ated with  the  following  pheno- 
mena : — 

1.  An  upper  dental  arch  that 
is  narrow  from  molars  to  canmes. 

2.  Apparent  protrusion  of  the 
upper  incisors. 

3.  A  lower  dental  arch  that 
may  be  almost  normal  m  width 
from  molars  to  canines  ;  as  a.  rule, 
it  is  relatively  wider  than  the 
upper  dental  arch. 

4.  Excessive  overbite. 
Figs.  293,  294,  and  295  repre- 
sent diagrammatically  from  three 

aspects  post-normal  occlusion  of  the  lower 
jaws  and  its  correction  by  forward  movement 
of  the  lower  jaw  and  expansion  of  the  upper 
jaw. 


9.  ' 

Fig.  292. — Rubber  band  holding  the  bow  in  position  in  the 
buccal  tubes  when  the  former  has  been  given  spring  to 
move  the  molars  lingually. 

1.  Spur  on  bow,  which  is  engaged  by  ligature  on  the  canine 
when  this  tooth  has  to  be  moved  distally. 

2.  The  bow  has  not  a  nut  to  engage  the  medial  end  of  the 
buccal  tube,  as  there  is  no  force  on  the  molar  in  a  distal 
direction. 

The  rubber  band  is  also  to  move  the  canine  distally.  The 
anchorage  offered  by  the  molar,  as  shown,  is  alone 
insufficient  for  movement  of  the  canine ;  inter-maxillary 
force  must  be  used. 

On  both  sides. 

17.  Fixed  Appliances. — Anchorage:  Simple 
(Inter-maxillary).  To  move  the  lower  jaw  for- 
ward the  resistance  of  all  the  teeth  of  the 
upper  jaw  is   used  as  anchorage.     The   upper 


187 


and  lower  bows  are  adjusted  to  accomplish 
any  other  necessary  movements,  or,  if  all  the 
teeth  are  correctly  placed,  the  upper  bow  is 
allowed  to  remain  passively  in  the  tubes ;  the 
nuts  engage  the  medial  ends  of  the  latter,  and 
the  bow  lies  in  contact  with  all  the  other 
teeth,  ligatures  being  used  wliere  necessary 
to  prevent  their  relapse,  as  well  as  to  give 
the  increased  anchorage  that  is  essential.  A 
hook  directed  forwards  is  soldered  on  the  bow 
opposite  the  canine — it  must  be  sufficiently 
far  back  that  when  a  rubber  band  is  stretched 
from  it  to  the  distal  end  of  the  buccal  tube 
on  the  lower  molar  band  of  the  same  side  it 
will  not  touch  the   canine  or   first    premolar; 


made  in  the  position  of  the  teeth  it  wUl  be  found 
that  the  upper  jaw  is  too  narrow  for  the  lower, 
it  being  assumed  that  the  bucco-lingual  relation 
of  the  molar  series  was  originally  correct  (see 
Figs.  293,  294,  295).  (This  is  because  the  molar 
series  of  teeth  diverge  from  before  backwards ; 
in  fact,  as  has  been  explained,  this  narrow- 
ness is  one  of  the  causes  of  the  post-normal 
position  of  the  mandible.)  In  the  treatment 
of  these  cases  the  upper  jaw,  therefore,  invari- 
ably needs  more  widenmg  than  the  lower,  and 
an  inspection  of  a  number  of  these  cases  will 
prove  at  once  that  the  «idth  of  the  lower  jaw  is 
much  more  nearly  normal  than  the  upper,  but  the 
abnormal  occlusion  of  the  two  is  in  harmony, 


Fig.  293. — Horizontal  sections  of  the  upper  and  lower  jaws  through  the  occlusal  plane,  where  upper  and  lower 
teeth  are  in  contact — upper  jaw  represented  by  a  light  line,  and  lower  jaw  by  a  heavy  line.  The 
lower  jaw  is  the  same  size  in  1,  2,  3,  and  i.     The  upper  jaw  is  the  same  size  in  1  and  3,  and  in  2  and  4. 

The  space  (a)  represents  normal  bucco-lingual  relation  of  upper  and  lower  teeth.  The  spaces  (b)  and  (c)  repre- 
sent abnormal  bucco-lingual  relation  of  upper  and  lower  teeth.  At  the  point  (b)  the  upper  and  lower  teeth 
are  too  far  from  one  another  bucco-lingually.  (See  Fig.  294  (2).)  At  the  point  (c)  the  upper  teeth  are 
too  nearly  vertically  over  the  lower  teeth.     (See  Fig.  294  (3).) 

I.  Normal  position  of  upper  central  incisors. 

II.  Normal  position  of  lower  central  incisors. 

III.  Normal  medio-distal  position  of  medio-buccal  cusp  of  first  lower  molars. 

IV.  Normal  medio-distal  position  of  medio-buccal  cusp  of  first  upper  molars. 

V.  Distal  end  of  normal  upper  and  lower  dental  arches. 

VI.  Distal  end  of  post-normal  lower  dental  arch. 

Note. — The  Arabic  flaures,  with  the  exphvnations  that  follow  them,  apply  to  the  horizontal  diagram  (Fi;.  293)  ami  to  the  vertical 
diagrams  (Figs.  :i94  and  295) . 

1.  Post-normal  occlusion  of  the  lower  jaw. 

2.  Original  post-normal  occlusion  of  the  lower  jaw — upper  arch  expanded.     The  result  is  that  the  upper  dental 

arch  is  too  wide  for  the  lower  in  its  present  position. 

3.  Post-normal  occlusion  of  the  lower  jaw  corrected  by  its  forward  movement,  but  with  the  original  contracted 

upper  arch.     The  result  is  that  the  lower  dental  arch  is  now  too  wide  for  the  upper. 

4.  Post-normal  occlusion  of  the  lower  jaw  is  corrected,  and  the  upper  dental  arch  is  expanded.     The  result  is 

normal  occlusion  of  all  the  teeth,  which  includes  normal  bucco-lingual  relations  as  shown  by  the  space  (o). 


the  wire  constituting  the  hook  is  arranged  to 
be  parallel  with  the  bow,  and  is  soldered  on 
the  aspect  towards  the  crowns  of  the  teeth,  so 
that  the  pull  of  the  rubber  band  may  be  as 
nearly  liorizontal  as  possible.  (See  Pig.  297.) 
Tlie  lower  bow  Ls  arranged  in  the  ordinary  way, 
and  all  the  teeth  are  ligatured  to  it ;  rubber 
bands  are  then  u.sed  from  the  liook  on  the 
upper  bow  to  the  distal  end  of  the  correspond- 
ing lower  buccal  tube;  this  constant  pull  brings 
tlie  low er  jaw  forw ard  A\ithout  moving  the  teeth 
through  the  bone.  The  strength  and  number  of 
the  rubber  bands  used  should  vary  witli  the  age 
of  the  patient,  but  in  no  case  is  it  necessary  to 
exert  more  than  a  light  constant  pull. 

If,  in  cases  of  post-normal  occlusion  of  the 
lower  jaw,  the  latter  is  moved  forward  to  its 
normal    position,    without    any    change    being 


as  far  as  an  abnormality  may  exhibit  harmony. 
Therefore,  if  the  upper  jaw  alone  be  widened 
that  harmony  is  disturbed  as  long  as  the  lower 
jaw  remains  in  its  jjost-normal  position,  and 
the  discomfort  occasioned  probably  induces 
the  patient,  consciously  or  unconsciously,  to 
try  and  accommodate  the  lower  jaw  to  the  upper ; 
tliat  is,  to  move  the  mandible  forwards  so  as 
to  restore  what  may  be  called  a  harmonious 
occlusion  between  the  two  jaws.  After  the 
age  of  twelve  this  natural  tendency  is  little  in 
evidence,  but  up  to  that  time  it  is  a  valual)le 
adjunct  to  inter -maxillary  force,  and  reduces 
the  necessity  of  antero-posterior  retention  to 
a  minimum. 

There  are  ca.ses  in  which  it  would  seem  that 
the  lower  jaw  is  held  in  post-normal  occlusion 
by  the  lingual  position  or  retroclination  of  the 


188 


upper  incLsors  and  by  the  lingual  position  of 
the  upper  canines,  deciduous  or  permanent. 
The  removal  of  these  obstructions  to  the  nor- 
mal position  of  the  mandible,  with  or  without 
widening  of  the  upper  arch  often  suffices  with 
very  little  aid  from  inter-maxillary  force  to  brmg 
the  lower  jaw  forward. 

18.  Removable  Appliances. — Me  Bride  has 
described    a    removable    apparatus — vulcanite 


Buccal  ■ 


.Ul 


'  Lingual 


n 

NORMAL 

ABNORMAL 

Fig.  294. — Bucco-lingual  view  of  the  first  molai's. 

(The  left-hand  arrow  points  buccally,  and  tlie  right-hand  one 
lingually.) 

The  teeth  in  correct  pcsition  are  represented  by  heavy 
lines,  the  teetli  in  abnormal  positions  by  light  lines. 

The  light  vertical  line  represents  abnormal  (contracted) 
position  of  the  naedio-buccal  cusp  of  the  first 
upper  molar ;  the  heavy  vertical  line  represents 
the  normal  (expanded  and  corrected)  position 
of  the  medio-buccal  cusp  of  the  first  upper  molars. 
They  also  represent  the  abnormal  and  normal 
positions,  respectively,  of  the  buccal  surfaces  of 
the  first  lower  molars.  The  expanded  position 
of  the  lower  molar  is  obtained,  not  by  expanding 
the  lower  molar  region,  but  by  moving  the  lower 
jaw  forward  as  diagranunatically  shown  in  Figs. 
293  and  296.     The  arable  figiiros  as  in  Fig.  296. 

plates — to  enable  the  lower  jaw  to  be  pulled 
forward ;  the  writer  does  not  consider  such 
an  appliance  to  be  practicable  and  sufficiently 
stable  for  the  work  it  is  intended  to  perform ; 
and,  if  it  were,  then  the  method  of  retaining  the 
appliance  and  the  arrangement  for  the  tractive 
force  are  not  to  be  recommended.  Probably 
the  only  way  of  bringing  the  lower  into  normal 


relation  with  the  upper  by  means  of  removable 
appliances  is  by  inducing  the  lower  jaw  to  come 
forward  without  using  any  direct  force.     As  has 


u 


(oJ 


Fig.   295. — Medio-distal  view  of  the  first  molars. 
The  teeth  in  correct  position  are  represented  by  heavy 

lines,  the  teeth  in  abnormal  positions  by  light  lines. 
The   vertical   line   represents    the   correct   position   of 

the   medio-buccal  cusp  of   the  first  upper   molar. 

The  arable  figiu-es  as  in  Fig.  293. 

been  stated  in  the  j)revious  paragraph  this  can 
be  done  by  expansion  of  the  upper  jaw,  including 
the  canines,  in  many  cases,  and   by  forward 


Fig.  296. — Diagram  to  show  that  in  effect  the  result 
of  medial  movement  of  the  lower  jaw  is  to  widen 
it;  in  other  words,  a  wider  portion  of  the  lower 
dental  arch  now  occludes  with  any  selected  point 
in  the  upper  dental  arch. 

The  lines  represent  the  same  lower  jaw,  and  are  the 
same  shape  and  size,  the  heavy  line  showing  it 
in  its  original  position,  and  the  dotted  line  in  its 
medial  position.  The  two  small  transverse  lines 
mark  the  same  point  on  both  dental  arches.  It 
is  apparent  that  the  effect  of  forward  movement 
of  the  lower  jaw  is  to  widen  it. 

movement  of  the  incisors  where  this  is  necessary. 
In  addition  the  vulcanite  expansion  plate  should 
provide  a  polished  inclined  plane  on  to  which 


189 


the  lower  incisors  impinge  when  the  mouth  is 
closed  (see  Figs.  307  and  355) ;  this  plane  gives 
rise  to  a  tendency  for  the  lower  jaw  to  be 
brought  forward.  The  posterior  edge  of  the 
"inclined  plane"  should  be  so  far  back  that 
the  patient  cannot  get  the  incisor  teeth  belmid 
it. 

On  one  side  only. 

19.  Fixed  Appliances. — It  Ls  doubtful 
whether  tliis  condition  actually  exLsts ;  it  is 
probable  that  it  is  frequently  a  symmetrical 
defect,  which  has  been  obscured  by  a  secondary 
malocclusion,  such  as  undue  forward  movement 
of  a  lower  molar.  On  the  other  hand  cases 
exist  that  apparently  have  no  other  explana- 
tion than  that  it  is  to  be  seen  clinically. 

Treatment  would  be  the  same  as 
described  in  paragraph  17,  but  adapting 
it  for  one  side  only. 

20.  Removable  Appliances. — Re- 
movable appliances  cannot  satisfactorily 
deal  w  ith  this  condition  ;  except  that 
unilateral  expansion  of  the  upper  arch 
will  bring  about  lateral  movement  of 
the  mandible,  in  a  mamier  similar  to 
the  production  of  medial  movement  as 
described  above. 


of  all  the  teeth  ;  these  teeth  are  all  securely 
ligatured  to  the  bow,  and  there  are  then  six 
(fewer  would  not  suffice)  or  eight  teeth 
opposed  to  four,  the  bow  having  been  closely 
fitted  to  all  these  front  teeth  and  the  nuts 
adjusted  to  engage  the  medial  ends  of  the 
tubes.  (See  Fig.  300,  right  side  of  figure.)  The 
nuts  are  now  to  be  turned  against  the  tubes — 
the  appliance  being  converted  into  a  jack- 
screw, — when  either  the  six  or  eight  anterior 
teeth  move  forwards  or  the  four  posterior 
teeth  move  backwards.  The  latter  is  the 
movement  that  is  anticipated,  but  if  the 
anchorage  is  insufficient,  and  there  is  a  doubt 
as  to  its  efficiency,  a  bow  must  be  fitted  and 
ligatured  to  the  lower  teeth,  and  inter-maxillary 
force  between  the  canine  of  the  same  jaw  as  the 


Fig.  297. — Upper  and  lower  bows  and  accessories,  except  wire 
ligatures,  in  position  for  medial  movement  of  the  lower  jaw. 

1.  1.   Upper  and  lower  molar  clamp-bands. 

2.  2.   Buccal  tubes. 

3.  Upper  bow. 

4.  Lower  bow. 

5.  Hook  soldered  to  upper  bow  for  attaclmient  of  rubber  band, 
which  is  also  attached  to  the  lower  buccal  tube.  This  rubber 
band  pulls  the  lower  jaw  medially. 

gether  is  rarely  practicable,  as  the  age    •>.  Plain  band  on  left  upper  central. " 

at    which    the    second    premolar    has  ''•  ^"''^'V  ""  ^'''""  "^  ^'  '"  T'''"''  ""^  "PP''''  ^"^  """^^^  ^°  ^^''^'^ 

re    ■      ii                 i     1     4.       1         1      u        -ti  displacement   towards   the  mcisal   edge    by  the  pull   of    the 

sufficiently    erupted    to    be    dealt    ^^•ltll  ^..^ber   band,  or  cervically  on   acount    of    the   slope   of   the 

often  closely  approaches  that  at  winch  central  incisors, 
the  second  upper  molar  erupts,  and  the 


D.  Distal  Movement 

(i)  First  Molars  and  Second  Premolars. 

On  both  sides. 

21.  Fixed  Appliances. — Anchorage  : 
Simple.  Distal  movement  of  the  first 
upper  molar  and  second  premolar  to- 


treatment  \\ould  then  involve  the  distal  move- 
ment of  that  tooth  also ;  but  while  the  second 
deciduous  molar  is  still  present  the  condition  is 
one  to  respond  favourably. 

In  patients  under  ten  years  of  age  tlie  second 
deciduous  molar  should  be  used  as  anchorage, 
if  it  is  still  sufficiently  firm  in  the  jaw  ;  otherw  ise 
the  first  permanent  molar  should  be  used  and  the 
case  treated  as  one  of  individual  tooth  move- 
ment (see  pp.  205  and  210);  inter-maxiUaiy 
force  can  then  lie  dispensed  with,  but  it  should 
be  remembered  that  this  force  can  give  very 
valuable  aid. 

In  the  treatment  of  a  case  of  this  nature  with- 
out inter-maxillary  force,  most  of  the  remain- 
ing teeth  must  be  in  situ  and  sufficiently  firm 
to  offer  some  resistance.  The  bows  having 
been  fitted  with  the  clamp-ljands  on  the  second 
deciduous  molars,  spurs,  directed  medially,  are 
soldered  to  the  bow  opposite  the  medial  aspect 


moving  molars,  and  the  distal  end  of  the  buccal 
tube  of  the  opposite  jaw,  must  be  resorted  to 
immediately,  and  if  it  happen  that  this  does 
not  suffice  the  head-gear  must  be  made  use  of. 
With  the  head-gear  all  other  anchorage  may  be 
discarded  or  ignored  except  in  the  intervals  when 
it  is  not  worn.  It  w  ould  be  unsafe  to  rely  on  the 
available  anchorage  (the  remainmg  teeth  in  the 
upper  jaw,  and  the  lower  jaw  itself)  in  patients 
over  ten  years  of  age,  unless  supplemented  by 
occipital  anchorage,  when  this  movement  could 
certainly  be  undertaken.  The  second  molar  (if 
it  has  to  be  included  in  the  movement)  will  be 
forced  distally  by  the  first  molar  with  which  it  is 
hi  contact ;  it  is  necessary  to  ligature  the  premolar 
to  the  molar  so  that  they  shall  move  together. 
(a)  Anchor  Clamp-band  on  First  Permanent 
Molar. — The  screw  of  the  band  should  be 
directed  distally ;  if  the  second  molar  is  un- 
erupted  the  surplus    should    be    cut    off ;    this 


190 


position  of  the  band  will  necessitate  a  reversal 
of  the  buccal  tube.  On  the  buccal  and  lingual 
surfaces  of  the  band  smaU  hooks  directed  back- 
wards should  be  soldered  ;  they  should  be  large 
enough  to  engage  a  small  rubber  band  if  neces- 
sary. The  distal  end  of  the  buccal  tube  may 
be  used  as  one  spur,  and  the  clamp-wire  as  the 
other  when  it  is  directed  distally  (see  Fig.  298). 
A  plain  band  is  cemented  to  the  second  pre- 
molar, bearing  hooks  on  the  buccal  and  lingual 
surfaces,  directed  forwards,  and  large  enough 
to  hold  rubber  ligature  bands.  The  two  teeth 
to  be  moved  are  now  coupled  together  by 
rubber  bands  if  they  are  not  in  contact,  and  by 
wire  ligatures,  if  they  are  already  in  contact ; 
the  latter  are  to  be  substituted  for  the  former 
when  the  premolar  touches  the  molar.  Wire 
could  be  used  from  the  beginning,  but  its 
rene^\al  as  the  tooth  moves  is  more  difficult. 


Fig.  298. — Arrangement  of  bands  and  spurs  for  coupling 
a  premolar  and  molar  together  for  distal  move- 
ment of  these  teeth.  They  are  held  together  by 
wire  ligatures ;  if  they  are  not  in  contact  rubber 
bands  are  first  used  to  accomplish  this. 

(h)  Anchor  Clamp-band  07i  Second  Premolar. 
If  the  conditions  are  such  that  the  premolar 
can  be  relied  on  to  push  back  the  molar  (the 
second  molar  being  unerupted  or  not  about  to 
erupt),  then  the  clamp-band  should  be  fitted 
to  the  premolar,  the  lingual  screw  being  again 
directed  distally ;  as  already  indicated  the  buc- 
cal tube  is  set  back  on  jiremolar  bands ;  then 
the  tube  buccally  and  the  screw  lingually  will 
keep  the  molar  in  its  bucco-lingual  position. 

The  bow  is  now  adjusted,  the  nuts  engaging 
the  medial  ends  of  the  buccal  tubes,  and  being 
so  situated  on  the  bow  that  the  latter  is  not 
in  contact  with  the  incisors.  The  case  is  then 
ready  for  the  application  of  occipital  traction 
in  order  that  the  teeth  may  be  moved.  As  it 
is  unlikely  that  the  patient  will  wear  the  head- 
gear continuously,  arrangements  must  be  made 
to  hold  the  movement  obtained  in  the  intervals 
when  it  is  not  worn.  This  is  done  by  using 
inter-maxillary  force  in  the  usual  way,  the  bow, 
etc.,  being  applied  in  the  lower  jaw. 

22.  Removable  Appliances. — In  reading 
this  paragraph  it  should  be  borne  in  mind  that 


the  second  deciduous  molar  or  second  premolar 
may  be  absent. 

(a)  Patients  under  Ten  Years  of  Age  :  Anchor- 
age :  Simple. — Anterior  teeth  and  bone  to 
resist  force  applied  to  move  posterior  teeth. 

If  there  is  a  space  in  front  of  the  second  pre- 
molar or  second  deciduous  molar,  or  first 
permanent  molar  in  the  absence  of  these  (and 
it  is  not  very  likely  that  cases  of  this  kind  wiU 
have  arisen  without  sucli  a  space),  a  well-fitting 
plate  is  made  from  a  plaster  impression  to 
embrace  the  teeth  accurately,  having  clasps 
from  behind  forward  for  the  most  distal  of 
the  anterior  teeth.  It  should  carry  powerful 
coil  springs  of  platuiized  gold  or  pianoforte 
wire  to  impuige  on  the  medial  surface  of  the 
f)remolar  or  cleciduous  molar,  or  permanent 
molar  should  it  stand  alone.  If  the  anterior 
teeth  are  not  further  forward  than  they  should 
be,  the  anchorage  «ill  be  sufficient  to  carry 
the  posterior  teeth  distally,  as  it  is  obtained 
directly  from  bone  and  teeth ;  but  if  the  in- 
cisors are  already  mclined  forward,  fixed 
appliances  should  be  used  with  mter-maxillary 
force.  If  the  plate  is  designed  to  expand,  as 
with  the  Badcock  screw,  this  movement  may  be 
combmed  with  what  is  the  primary  movement 
so  far  as  this  paragraph  is  concerned.  The 
edge  of  the  plate  engaging  the  lingual  surfaces 
of  the  posterior  teeth  should  be  straight. 

(b)  Patients  over  Ten  Years  of  Age. — Fixed 
appliances,  with  the  greater  possibilities  of 
satisfactory  anchorage,  should  be  used,  unless 
forward  movement  of  the  anterior  teeth  is 
desired ;  for  with  a  removable  appliance  this 
\\ould  almost  certainly  occur  at  this  age,  unless 
the  second  premolar  is  inierupted,  when  the 
plate  can  be  made  more  stable. 

'  Another  method,  applicable  in  (a)  and  (b) 
where  circumstances  permit,  is  to  vulcanize  in 
the  plate  a  small  screw  occupying  the  space 
of  the  second  deciduous  molar  on  both  sides, 
its  distal  end  being  free  and  reaching  to  the 
medial  surface  of  the  first  molar.  A  nut 
engages  the  free  end  of  the  screw.  By  turning 
the  nut  the  posterior  teeth  will  be  forced 
distally.  A  suitable  screw  can  be  made  from 
the  end  of  a  bow,  with  a  nut  as  long  as  can 
be  fitted  into  the  space ;  the  nut  engages  the 
medial  surface  of  the  anterior  of  the  two  teeth 
to  be  moved.  This  device  may  be  employed 
without  a  plate ;  in  that  case  the  threaded 
wire  on  which  the  nut  runs  is  soldered  to 
the  medial  surface  of  a  band  on  the  molar  in 
order  that  the  small  appliance  may  be  secure 
(see  p.  234,  and  Fig.  299).  The  iuit,  in  this 
instance,  operates  against  the  distal  surface  of 
the  tooth  immediately  in  front  of  the  space. 
To  increase  the  area  of  contact  of  the  nut 
an  oblong  piece  of  plate  may  be  soldered  to 
its    medial    end ;    this   would    also   .serve  as  a 


191 


guide  in  turning  the  nut  a  given  amount. 
In  treating  a  ease  in  this  way  everything  has 
to  be  exceedingly  small,  but  the  short  nut 
necessary  at  the  start  may  be  replaced  by  longer 
ones  as  the  space,  resulting  from  tooth  move- 
ment, increases.  It  must  be  observed  that 
the  anchorage  Ls  sufficient  to  ensure  the  molar 
moving  and  not  the  other  teeth.  Tliis  method 
may  be  used  as  an  auxiliary  to  the  other  methods 
described. 

See  also  paragraph  24.  In  the  lower  jaw 
this  appliance  can  be  successfully  used  on  both 
sides. 

On  one  side  only. 

2.3.  Fixed  Appliances. 

Anchorage :  Keinjorced  Simple.  Auxiliary 
Anchorage :  The  opposing  jaw  (intcr-maxillary 
force).     The  bow  is  applied  as  wlien  this  move- 


FlG.  299. — Retention  and  enlargement  of  a  space 
between  two  teetli.  It  is  not  necessary  tliat  the 
bow  should  be  used  at  the  same  time. 


ment  has  to  be  performed  on  both  sides.  The 
anchorage,  however,  can  be  better  secured, 
as  all  the  remaming  teeth  are  available  to 
move  one  tooth.  The  bow  Ls  arranged  as  in 
the  other  case,  except  that  all  tlie  spurs  are 
in  the  same  direction,  the  bow  is  considered  as 
a  straiglit  wire,  and  the  nut  on  the  side  on 
which  the  teeth  have  not  to  be  moved  kept 
forward,  so  as  not  to  touch  the  front  of  the  tube. 
All  the  available  teeth  are  ligatured  to  tlio  bow 
in  such  a  way,  by  means  of  the  spurs,  that  they 
oppose  the  distal  movement  of  the  molar  as 
the  nut  is  tm'ued  against  the  front  of  the  buccal 
tube  on  the  misplaced  tooth  (see  Fig.  300). 
The  anchorage  described  should  be  ample,  but 
if  for  any  reason  it  is  desh-ed  to  augment  it, 
this  may  be  done  by  means  of  inter -maxillary 
force. 

24.  Removable. — This  operation  is  precisely 
the  same  as  No.  22,  except  that  the  movement 


is  required  on  one  side  only,  and  so  the  same 
appliance  adapted  to  do  this  may  be  used.  But, 
in  place  of  the  coil  sprmgs  or  jack-screws,  a 
spring  of  the  Coffin  type  may  be  employed  (see 
Fig.  301).  the  plate  being  divided  in  front  of 
the   more    medial    tooth    to    be    moved.     The 


Fio.  300. — Wire  bow  arranged  to  move  the  first  right 
lower  molar  distally ;  this  tooth  has  moved 
medially,  probably  on  account  of  the  early  removal 
of  the  second  deciduous  molar.  All  "the  teeth 
from  the  first  right  premolar  to  the  left  lateral 
are  tied  to  the  bow ;  in  each  ligature  a  spur  on 
the  bow  is  included,  so  that  the  total  resistance 
of  each  ligatured  tooth  may  be  opposed  against 
the  molar  when  the  nut  in  the  front  of  the  buccal 
tube  is  turned  against  it.  This  resistance  will 
suffice  to  move  the  molar  distally;  inter-maxillary 
force  may  be  used  to  increase  the  resistance  of 
the  anterior  teeth. 

saw  cut  should  extend  to  the  posterior  edge 
in  the  case  of  an  upper  plate,  and  in  the  case 
of  a  lower,  as  shown  in  Fig.  301.  In  order 
to  maintaui  stability  and  accurate  relation- 
ship between  the  two  portions  of  the  plate, 
a  wire  fixed  into  one  piece  of  the  plate  should 


Fig.  .301. — -Vulcanite  plate  with  modified  Coffin 
sprmgs  to  increase  the  space  between  the  canines 
and  first  molars,  where  the  plato  is  split  on  each 
side.  Four  clasps  hold  the  plate  in  position. 
(After  Balding.) 

engage  a  tube  in  the  other  piece  (the  wire 
fitting  the  tube  accurately  ami  being  parallel 
with  the  desired  Une  of  movement  of  tlie 
tooth  or  teeth) ;  one  of  these  attachments 
should  be  near  each  extremity  of  the  plate. 
They  were  suggested  to  the  writer  by  F.  L. 
Aubrey. 


192 


(ii)   First  Premolars  and  Canines. 
On  both  sides. 
25.  Fixed  Appliances. — Anchorage  : 

(a)  Opposing  jaw  (inter-maxillary  force).  The 
teeth  in  the  opposing  jaw  are  station- 
ary or  moved  reciprocally  as  desired. 

(6)  Recijarocal  by  movement  of  the  corre- 
sponding first  molar  forward. 

(c)  Reciprocal  by  movement  of  the  incisors 

forward. 

(d)  Reciprocal  by  movement  of  the  premolars 

for^^  ard  on  the  same  side  of  the  opposmg 
jaw. 

Apparatus. — Clamp-bands  on  the  first  per- 
manent molars,  and  bows. 

(a)  The  most  satisfactory  method  is  by  anchor- 
age obtained  from  the  opposite  jaw.  (See  also 
(d)  below.)  Spurs  are  soldered  to  the  bow  distal 
to  the  teeth  to  be  moved,  and  at  any  convenient 
point  a  hook,  for  an  intcr-maxi]lary  ligature, 
is  also  soldered  to  the  bow.  The  premolar  and 
canine  are  ligatured  to  the  arch  as  shown  in 
Fig.  292,  1),  the  ligatures  engaging  the  spurs, 
which  are  dhected  distally.  The  effect  of  this 
is  to  puU  the  bow  forward  out  of  its  buccal 
tubes,  but  the  mter-maxUlary  ligature,  which 
should  now  be  applied,  prevents  this,  and 
indeed  pulls  back  the  bow  and  with  it  the 
teeth  whose  ligatures  engage  the  spurs  on 
the  bow,  which  must  not  be  in  contact  with 
the  mcisors.  In  such  a  case  as  this  the  nuts 
should  be  turned  forward  or  entirely  removed, 
so  that  as  the  teeth  and  bow  are  pulled  back 
the  latter  wUl  slide  in  the  tube.  The  bow 
on  the  opposing  jaw  should  be  wired  to  all  the 
teeth. 

(b)  Reciprocal  anchorage  by  forward  move- 
ment of  the  corresponding  first  permanent 
molars. 

The  same  apparatus  is  used  except  that  it 
need  only  be  applied  to  the  jaw  being  operated 
on.  The  spurs  on  the  bow  are  to  be  arranged 
as  before,  that  is,  ju.st  behind  the  teeth  to  be 
moved  and  sloping  distally.  The  hook  for  a 
rubber  ligature  is  also  arranged  simOarly,  but 
instead  of  passing  to  the  distal  aspect  of  the 
corresponduig  buccal  tube  in  the  opposite  jaw, 
it  passes  to  this  point  on  the  clamped  molar 
of  the  same  side  of  the  same  jaw  (see  Fig.  292). 
The  teeth  should  be  moved  one  at  a  time  ;  if  the 
canine  offers  great  resistance  occipital  anchorage 
or  inter-maxillary  force  must  be  resorted  to. 

In  (a)  and  (b)  the  spurs  may  have  to  be  moved 
to  more  distal  positions  as  the  teeth  travel 
back. 

(c)  Reciprocal  anchorage  by  forward  move- 
ment of  the  incisors,  the  action  being  similar  to 
that  when  molars  give  the  anchorage,  except 
that  in  this  case  the  premolars  are  to  move 


as  well  as  the  incisors.  The  clamp-bands  may 
be  attached  to  the  first  molars  or  first  premolars 
of  the  same  jaw.  In  the  first  instance  the  first 
premolars  and  canines  are  ligatured  to  spurs  on 
the  bow  as  previously  described;  the  incisors 
are  also  ligatured  to  the  bow,  and  it  is  the  force 
necessary  to  displace  these  that  moves  the 
premolars  and  canines  distally ;  each  tooth 
should  he  dealt  with  separately  to  avoid  strain- 
ing the  anchorage — the  premolars  first,  and 
then  the  canines.  The  nuts  may  be  turned 
as  deshed,  to  accommodate  the  incisors  as  they 
move,  but  not  till  after  that  has  been  done 
should  the  ligatures  on  the  canines  and  pre- 
molars be  tigiitened. 

\Vlien  the  first  premolars  are  used  as  anchorage, 
pressure  is  brought  to  bear  directly  on  these 
teeth,  the  anterior  teeth  providing  the  resistance 
necessary  to  move  first  the  premolar  and  then 
the  canme.  The  nuts  must  be  kept  turned 
well  up  against  the  front  of  the  tubes.  The 
canme  is  moved  by  a  spur  on  the  bow  directed 
distally,  or  it  may  be  ligatured  either  by  wire  or 
rubber  to  the  premolar  itself.  The  four  anterior 
teeth  would  probably  not  be  able  to  give  simple 
anchorage  for  the  movements  under  considera- 
tion;  for  this  reason  any  attempt  to  move  both 
the  premolar  and  canine  distally  at  the  same 
time  should  not  be  made. 

{d)  Probably  the  best  method  of  all  by 
which  to  accomplish  this  procedure  is  as 
an  individual  tooth  movement.  Plain  bands 
with  spurs  directed  forward  are  cemented  to 
the  teeth  to  be  pulled  back,  the  necessary 
anchorage  being  derived  from  the  opposite 
jaw,  reciprocally  if  any  teeth  (which  should 
have  similar  attachments)  are  to  be  moved 
forwards  (see  Fig.  302,  b),  or  by  simple  mter- 
maxUlary  traction  from  the  molar  tube  (the 
wire  bow  beuig  in  position  and  wired  to 
several  teeth)  if  a  reciprocal  movement  is 
not  requhed  (see  Fig.  302,  a).  The  former 
method  is  particularly  desiiable  when  the  pre- 
molars are  to  be  elongated ;  if  the  elongation 
needed  is  only  slight,  the  anchorage  should  be 
from  the  molar  tube,  not  directly  from  the  teeth, 
as  the  direction  of  force  is  then  more  nearly 
vertical.  In  the  case  of  the  canine  band,  an 
elongated  spur,  extendmg  beyond  the  tip  of 
the  tooth,  and  bent  so  as  to  hold  a  rubber 
band,  increases  the  leverage,  and  so  the 
resistance  offered  to  movement  is  more  easily 
overcome. 

These  several  methods  of  movmg  canines  and 
premolars  may  be  used  m  combuiation ;  it  will 
probably  be  found  that  this  is  the  most  desirable 
plan ;  for  instance,  when  the  four  incisors  are 
used  to  move  the  premolar  directly  by  means  of 
a  clamp-band  and  bow,  the  anchorage  of  the 
one  jaw  may  be  considerably  augmented  by 
inter-maxillary  anchorage. 


193 


2G.  Removable. 

First  Premolars. — By  means  of  coil  springs  as 
descrilx'd  for  second  premolars  and  molars  under 
paragraph  22.  If  necessary  make  room  for  the 
sprbig  between  the  canine  and  first  premolar 
by  separatuig  these  two  teeth  (see  Fig.  303). 

Canines. — By  means  of  a  Coffin-t>'pe  spring 
in  the  buccal  sulcus,  its  medial  end  engaging 
the  medial  surface  of  the  canine  from  the  buccal 
aspect,  and  its  other  end  attached  to  the  plate 
j)alatally  and  passing  to  the  buccal  vestibule 
eitiier  in  front  of  or  behind  the  first  molar. 

Anotlier  method  is  to  cement  to  the  canine 
a  plain  band  with  buccal  and  lingual  spurs,  both 
directed  medially ;  into  tlie  plate  a  wire  is  fixed 
to  pass  along  the  distal  surface  of  the  first  molar, 
and  is  bent  into  a  liook  directed  backwards  at 
the  disto-buccal  corner  of  the  tooth ;  on  the 
palatal  surface  of  the  plate,  opposite  and  near 
the  first  molar,  a  hook  directed  dlstally  is 
vulcanized.  Two  rubber  bands  are  stretched 
from  the  canine  to  the  attachments  on  the  plate 
near  the  corresponding  molar,  one  being  buccal 
and  the  other  palatal  to  the  teeth.  The  spurs 
on  tlic  canine  band  should  be  towards  the  distal 
aspect  of  that  tooth.  The  jJate  should  accu- 
rately fit  the  medial  surface  of  the  first  molar  if 
that  surface  is  exposed. 

On  one  side. 

27.  Fixed  Appliances. — As  in  paragraph  25, 
the  apparatus  being  arranged  to  operate  on  one 
side  only. 

28.  Removable  Appliances. — As  in  para- 
graph 26,  the  apparatus  being  arranged  to 
operate  on  one  side  only. 


is,  when  the  abnormal  position  of  the  lower  jaw 
and  teeth  have  given  rise  to  inferior  protrusion. 
The  treatment  is  the  reverse  of  that  adopted 
in  cases  of  inferior  retrusion.  Upper  and  lower 
bows  are  applied,  tlie  latter  having  a  hook  for 
the  application  of  intcr-maxillary  force  about 
opposite  the  canine  ;  at  its  other  end  the  rubber 


bow    must 


Fio.  302. — Tlie  left-hand  figure,  A,  shows  movement  of  the  first  upper 
premolar  distally  by  means  of  inter-maxillary  force  applied  from  the 
lower  jaw  (simple  anchorage).  The  right-hand  figure,  B,  shows 
movement  of  the  upper  canine  distally  and  of  the  lower  first  premolar 
medially  (reciprocal  anchorage). 

The  rubber  bands  are  attached  to  spurs  or  plain  bands,  except  in  the  case 
of  the  molar,  when  the  distal  end  of  the  buccal  tube  is  used. 


(iii)   The  Lower  Jaw. 

29.  Fixed  Appliances. 

(Removable  ajipliances  are  not  applicable.) 

Anchorage:  The  opposing  jaw  {inter-maxillary 
force). 

Distal  movement  of  the  lower  molars  and 
])rem(ilars  and  canine  is  only  necessary  when  the 
lowei-  jaw  itself  has  to  be  moved  distally,  that 


Fig.  303.-  \  uk.Liuu  pl.Lli  \\ii\i  two  cuil  -springs; 
one  to  move  the  right  first  premolar  distally, 
and  the  other  to  move  the  right  central  and 
lateral  labially.  Clasp  wires  on  the  first  molars 
retain  the  plate  in  position. 

band  exerting  the  inter-maxUlary  force  is  caught 
on  the  distal  end  of  the  buccal  tube  of  the  clamp- 
band  m  the  upper  jaw.  The  type  of  anchorage 
obtauied  from  the  upper  jaw  depends  on  the 
movement  desired  there.  If  the  upper  dental 
arch  is  to  remain  stationary,  then  the  wire 
be  .suitably  bent,  and  all  the 
teeth  ligatured  to  it.  If  it  is 
desired  to  pull  the  upper  molar 
forward,  then  it  is  necessaiy  to 
have  the  nuts  turned  forward  so 
that  the  force  shall  be  exerted 
on  those  teeth  only.  If  the  first 
permanent  upper  molar  is  to 
remain  in  its  iJosition  but  the 
upper  incisors  are  to  go  forward, 
then  the  force  used  to  pull  back 
the  lower  jaw  is  applied,  recipro- 
cally, to  do  this ;  it  cannot  be 
directly  applied,  but  acts  through 
the  medium  of  the  upper  molar, 
which  serves  as  a  connecting  Imk 
or  passiv'e  agent  in  the  two  move- 
ments— the  molar  itself  does  not 
move.  This  molar  has  pressure  acting  on  it  in  a 
medial  direction  from  the  lower  jaw,  and  in  a 
distal  direction  from  the  up^Jcr  incisors  ;  so  long 
as  the  two  forces  are  appro.ximately  equal  the 
molar  will  not  move.  If  it  is  desired  to  move 
the  upper  incisors  forward  without  the  use 
of  the  first  molars  as  a  connecting  link,  tlien 
the    rubber    band    must    be    attached    in    the 


194 


upper  jaw  to  a  hook  soldered  on  the  upper 
bow  just  in  front  of  the  nut,  which  would  not 
be  serving  any  special  purpose. 

If  the  teeth  liave  to  be  moved,  apart  from  tlie 
movement  of  the  lower  jaw  distally,  it  is 
accomplished  as  descrilied  in  parasfraphs  21,  25, 
38,  and  40. 

E.    Depression 

Tliis  movement,  30-33,  is  one  of  tlie  most 
difficult,  and  one  that  is  rarely  needed.  It 
might  be  attempted  by  making  a  vulcanite 
plate  to  cover  the  occlusal  surfaces  of  those 
teeth  to  be  depressed.  The  writer  recalls  a 
case  \\here  this  inadvertently  happened  owing 
to  such  treatment.  It  would  be  well  to  note 
whether  the  teeth  ojiposing  the  covered  teeth 
were  also  depressed.  Grinding  of  the  occlusal 
surfaces  of  the  teeth  will  probably  have  to  be 
resorted  to. 

The  treatment  of  these  cases  will  be  again 
referred  to  under  individual  movement. 

F.  Elongation  of  Molars,  Premolars  and  Canines 

(i)  In  both  Jaws  simultaneously 

This  movement  is  usually  needed  for  the 
lower  jaw  more  than  for  the  upper. 

34.  Fixed  Appliances. — Anchorage:  Inter- 
maxillary, Reci'procal.  —  The  princijJe  to  be 
adopted  is  that  of  inter-maxUlary  force  acting 
reciprocally  to  bring  the  opposing  teeth  of  the 
two  jaws  closer  together,  so  that  the  bones  them- 
selves are  further  apart,  when  the  teeth  are  in 
the  position  of  occlusion,  than  was  originally 
the  case. 

A  suitable  hook  directed  rootwards  Ls  soldered 
to  the  buccal  surface  of  the  lower  molar  band 
at  the  medio-buccal  corner,  and  from  this  a 
rubber  band  is  stretched  to  engage  the  distal 
end  of  the  buccal  tube  on  the  upper  molar  (or 
a  special  hook  as  for  the  lower)  and  the  usual 
inter-maxillary  hook  on  the  upper  bow  (see 
Fig.  304),  or  it  may  engage  hooks  on  bands  on 
the  premolars.  The  attachment  to  the  upper 
bow  is  only  used  when  the  lower  jaw  has  to 
be  moved  forward.'  Another  band  should  be 
stretched  from  the  lower  molar  to  the  lower 
premolars  (or  a  hook  on  the  bow  in  this  region) 
and  first  upper  premolar. 

The  manner  of  application  of  these  rubber 
ligatures  may  be  varied  considerably.  Wlien 
they  pass  over  hooks  on  the  bow  instead  of 
directly  to  the  teeth,  the  latter  must  be 
securely  ligatured  to  the  bow. 

35.  Removable  Appliances. — This  move- 
ment is  obtained  by  allowing  the  teeth  to 
elongate  in  their  sockets,  and  tliLs  happens 
when  the  position  of  occlusion  is  made  impos- 
sible. All  that  is  necessary  to  prevent  the 
teeth  coming  into  occlusion  is  to  place  in  the 
upper  jaw  a  vulcanite  plate — a  bite-plate — that 


has  been  made  sufficiently  thick  behind  the 
incisors  to  compel  the  lower  incisors  to  strike 
this  thickened  portion  of  vulcanite  before  the 
posterior  teeth  of  the  two  jaws  meet  one 
another,  and  thereby  keep  them  from  coming 
into  contact  at  any  time  (see  Fig.  355).  The 
plate  must  be  worn  constantly,  even  during 
meals,  and  it  will  be  found  that  the  teeth  move 
towards  one  anotlier,  and  ultimately  meet 
again.  The  time  necessary  varies  from  one  or 
two  months  to  four  or  five  times  as  long.  If  the 
movement  requu'ed  is  considerable  the  vulcanite 
should  be  thickened  from  time  to  time,  instead 
of  being  made  the  requisite  thickness  at  first, 
as  the  discomfort  caused  would  probably  be 
sufficient  to  be  noticed  and  mastication  would 
be  unduly  interfered  \\ith. 

This  is  a  movement  that  is  very  frequently 
called  for ;  it  is  necessary  in  all  cases  in  which 
the  upper  centrals  overlap  the  lower  centrals 


Fig.  304. — Shows  the  application  of  inter-maxillary 
force  to  elongate  the  two  molars,  as  well  as  to 
move  the  lower  jaw  medially. 

(1)  Anchor  clamp-band. 

(2)  Buccal  tube. 

(3)  Upper  bow. 

(4)  Lower  bow. 

(5)  Hook,  soldered   to  bo%v,  for  attachment  of 
the  rubber  band  to  the  upper  bow. 

(6)  Spurs  on  the  buccal   tubes  for  attachment 
of  the  rubber  bands  to  the  molars. 

by  more  than  one-third  of  their  height ;  such  an 
arrangement  precludes  the  possibOity  of  normal 
occlusion,  and  in  many  instances  it  is  impossible 
to  pull  back  upper  incisors  tUl  thLs  condition 
has  been  corrected  (see  Fig.  305) ;  in  treatment 
these  points  are  frequently  neglected.  Usually 
other  movements  are  necessary  in  these  cases. 
They  may  be  done  simultaneously,  or  the  plate 
may  be  used  before  or  after  the  other  treatment. 
During  the  period  of  movement  of  teeth  the 
bite  is  usually  opened  somewhat  by  the  teeth 
being  unable  to  inter-digitate  correctly,  and  even 
after  normal  occlusion  has  been  established 
there  may  be  some  permanent  raismg  of  the 
bite.  When  the  overbite  is  only  a  little  in 
excess  of  normal  this  opening  due  to  general 
tooth  movement  may  suffice. 

(ii)  In  one  Jazv  only 
36.    Fixed  Appliances. — Anchorage  :  Inter- 
maxillary, Simple.— Exactly  as  in  34,  but  with  the 


195 


appliances  arranged  to  move  the  teetli  in  one 
Jaw  only,  by  arrangintr  tlie  inter-maxillary  force 
so  that  it  is  clelivertd  from  a  simple  reinforced 
anchorage  instead  of  acting  reciprocally. 

37.  Removable  Appliances.  —  Anchorage  : 
Simple. — If  the  lower  teeth  only  are  to  elongate, 
the  upper  plate  should  have  cleats  attached  to  it ; 
these  cleats  should  engage  the  occlusal  surfaces 
of  the  molars  and  premolars — m  the  former  by  a 
simple  wire  engaging  the  lingual  sulcus,  and  in 
the  latter  by  two  pieces  of  wire  passing  from 
the  medio-lingual  and  dLsto-lingiial  aspects  of  the 
tooth  towards  the  centre  of  the  crown. 

If  the  upper  teeth  are  to  elongate  and  not  the 
lower,  a  lower  plate  is  constructed  w  ith  cleats  to 
engage  the  occlusal  surfaces  of  the  molars  and 
premolars  as  just  described.  The  plate  should 
not   cover  the  lingual   surfaces   of  the   incisor 


Fig.  305. — Shows  the  relation  of  the  upper  and  lower 
incisors  to  one  another  in  cases  of  excessive 
overbite  (post-normal  occlusion  frequently  accom- 
panies this  condition).  The  overbite  must  be 
corrected  if  it  is  desired  to  bring  about  normal 
occlusion  of  the  incisors. 

teeth  and  gum  margin,  but  consist  m  this 
region  of  an  oval  wire,  which  passes  either  just 
above  or  just  below  the  necks  of  the  teeth  (see 
Fig.  343). 

If  the.se  movements  are  reciuu'ed  on  one  side 
only,  the  apparatus  can  be  arranged  accordingly. 
(See  also  references  to  elongation  under  "  Indi- 
vidual Tooth  Movement  ",  pp.  205,  210,  213.) 

G.  Rotation 

Only  possible  as  an  individual  tooth  move- 
ment . 

n— INCISORS 

A.  Labial  Movement :    Upper  and  Lower 

38.  Fixed  Appliances. 

Anchorage :  Simple. — Upper  and  lower  bows 
are  adjusted  as  usual ;  hooks  for  inter-maxUlary 
elastics  should   be  attached  to  the  bows  if  it 


is  thought    that   inter-maxillary  force   will   be 
needed. 

The  bow  is  bent  to  pass  across  the  necks  of 
the  teetli,  so  as  just  to  escape  touching  the 
soft  tis.sues,  even  though  in  actual  contact  with 
the  teeth.  It  should  project  one  to  two  milli- 
metres beyond  the  teeth,  but  it  is  preferable  to 
let  the  patient  wear  the  bow  in  contact  with 
them  for  a  few  days  and,  when  he  is  accus- 
tomed to  it,  to  move  it  forward  by  means  of 
the  nuts  before  applying  ligatures.  It  should 
be  borne  in  mind  that  it  is  better  to  turn  the  nuts 
forward  only  once  in  two  weeks  or  so,  and  to 
move  the  teeth  out  to  the  bow  in  this  position 
(one  or  two  millimetres  beyond  the  teeth)  by 
means  of  the  ligatures,  tightenmg  and  renewing 
them  as  necessary. 

Ligatures,  W'U'e  or  silk,  are  now  applied  to 
the  teeth  to  be  moved,  and  made  sufficiently 
taut  just  to  avoid  causing  the  patient  pain — 
whether  it  be  immediate  or  otherwise.  In 
addition  to  the  amount  of  immediate  tooth  move- 
ment thus  obtained — dependent  on  the  force 
applied  as  the  ligature  is  tied,  the  spring  of  the 
bow,  and  its  distance  from  the  labial  surface 
of  the  teeth — the  spring  of  the  bow  is  constantly 
operating  to  carry  the  teeth  forward;  for  its 
anterior  portion  will  have  been  pulled  hi,  and 
this  causes  the  side  portions  to  bulge  out  (see 
Fig.  334),  the  nuts  being  hard  against  the 
anterior  ends  of  the  buccal  tubes  ;  the  tendency 
of  the  bow  to  resume  its  origuial  shape  re- 
sults in  the  forward  movement  of  the  incisors. 
The  ligatures  should  be  tightened  or  renewed 
once  or  twice  a  week ;  the  latter  is  prefer- 
able as  then  the  operator  has  better  control 
of  the  apparatus,  and  its  cleansing  can  be 
more  satisfactorily  supervised ;  when  teeth  are 
moving  cjuickly  ligatures  are  likely  to  be  very 
loose  at  the  end  of  a  week.  As  the  teeth 
move  forward  and  come  in  contact  with  the 
bow,  the  nuts  should  then  be  turned,  and  then 
only,  so  as  to  bring  the  bow  one  or  two  milli- 
metres in  advance  of  the  teeth  agam,  and  the 
process  of  ligaturing  continued ;  bj'  repetition 
of  these  operations  teeth  may  be  moved  as  far 
forward  as  desired.  If  this  movement  is  con- 
siderable, it  may  be  that  in  time  the  length  of 
the  bow  will  not  suffice  for  its  support  in  the 
buccal  tubes  of  the  anchor  bands ;  m  such  a 
case  a  new  bow  must  be  substituted.  If,  at 
the  same  time,  much  increase  in  width  of  the 
arch  of  teeth  in  the  canine  region  is  needed,  a  re- 
bending  of  the  bow  wOl  probably  be  necessary 
in  the  course  of  treatment,  so  that  it  shall  serve 
as  an  accurate  mould  for  the  new  positions  of 
the  teeth,  and  yet  never  be  in  a  position  of  in- 
efficiency as  regards  its  work,  or  discomfort  as 
regards  the  patient. 

39.  Removable    Appliances.  —  Anchorage: 
Simple. — Springs   of   platinized  gold   wire  are 


196 


the  most  suitable  devices  for  developing  the 
necessary  force.  They  should  be  the  usual  coil 
spring  arranged  to  exert  its  force  by  uncoiling  ; 
the  force  should  be  delivered  as  near  the  neck  of 
the  tooth  as  possible.  The  spring  for  the  right 
central,  or  right  central  and  lateral,  should 
come  from  the  left  side  of  the  plate  and  vice 
versa.  Rubber  or  wooden  wedges  are  also  used 
to  move  incLsors  forward ;  the  plate  is  made 
thick  opposite  the  tooth  (or  teeth)  to  be  moved, 
and  an  inverted  wedge-shaped  piece  is  cut  out, 
and  mto  the  slot  so  formed  is  tightly  fitted  a 
piece  of  orange  wood  or  rubber.  The  latter 
moves  the  tooth  by  its  inherent  po\ier  of  elas- 
ticity ;  the  former  s\\ells,  when  moistened,  and 
so  moves  the  tooth.  Small  screws  passing 
through  the  vulcanite  to  impinge  on  the  palatal 
surface  of  an  upper  incisor  are  also  used.  They 
may  be  vulcanized  in  the  plate,  or  fixed  in  the 


Fig.  306. — The  two  bows  are  identical  as  regards 
their  length  and  the  position  of  the  nuts. 

The  interrupted  lines  show  the  original  shape  of  the 
wire  bow ;  the  uninterrupted  lines  show  that  the 
bow  becomes  sliorter  as  it  widens  if  the  nuts 
remain  in  their  original  position  in  contact  with 
the  medial  ends  of  the  buccal  tubes. 

front  part  of  the  plate  (which  has  been  thickened) 
after  it  has  been  made.  The  end  of  the  screw 
should  be  cut  square  so  that  it  may  be  readily 
turned.  Por  this  purj)ose  a  watch  key  is  well 
adapted.  A  small  nut  may  be  vulcanized  in 
the  plate  to  take  the  screw,  which  can  then  be 
readily  renewed  when  desired  (see  Fig.  291, 
a  and  c). 

B.    Lingual  Movement  of  Incisors 

40.  Fixed  Appliances. — Anchorage:  Becipro- 
cal  ;  Inter-inaxillury,  simple  or  reciprocal ; 
Occipital. 

(a)  By  the  spring  of  the  bow,  in  conjunction 
with  expansion  m  the  molar  region. 

As  the  wire  bow  widens  it  necessarily  becomes 
shorter  (see  Fig.  306),  its  position  in  relation  to 
the  buccal  tubes  remainmg  the  same ;  it  will, 
therefore,  exert  pressure  on  the  mcisors  and  move 
them  in  a  palatal  or  Imgual  direction.     In  order 


that  this  movement  may  be  increased,  the  nuts 
are  turned  forward  on  the  bow  and  kej)t  free  from 
the  buccal  tubes,  or  they  are  removed  altogether  ; 
then  as  the  upper  incisors  move,  the  bow  slides 
I  back  in  the  tubes  of  the  clamp-bands,  and 
permits  of  more  shortening  of  the  dental  arch 
than  would  be  possible  whilst  the  nuts  engaged 
the  tubes. 

(6)  By  mter-maxillary  force. 

Hooks  are  soldered  m  the  canme  region  to  the 
I  bow  of  that  jaw  whose  uicisors  are  to  be  pulled 
back ;  to  these,  mter-maxillary  ligatures  are 
attached,  and  stretched  so  as  to  engage  the  distal 
end  of  the  buccal  tube  of  the  clamp-band  m 
the  opposite  jaw,  to  which  a  bow  must  be  fitted 
and  a  sufficient  number  of  teeth  ligatured  to  it 
to  afford  the  necessary  anchorage.  The  nuts 
are  kept  quite  free  of  the  tubes,  as  regards  the 
bow  that  is  moving  the  mcisors  back.  The  full 
force  exerted  by  the  rubber  bands  is  thus  brought 
to  bear  on  the  incisors. 

In  cases  of  this  kind,  the  bows  should  not 
rest  at  the  necks  of  the  teeth  but  at  the  centre 
of  the  labial  surfaces  (the  greater  power  thus 
obtained  necessitates  the  use  of  less  force  to 
obtain  the  same  amount  of  movement).  It  wiU 
usually  be  found  that  teeth  recjuhing  this  move- 
ment have  their  long  axes  slopmg  downward  and 
forward  in  the  case  of  the  upper  incisors ;  this 
slope  prevents  the  bow  restmg  at  the  desired  spot 
on  the  labial  surface  of  the  tooth,  so  m  order 
to  achieve  this  object,  a  plam  band,  with  the 
seam  on  the  labial  surface  and  a  notch  cut  in 
the  seam,  is  made  for  one  or  both  central  in- 
cisors, and  in  this  notch  the  bow  rests  (see 
Figs.  337  (a)  and  297).  This  may  have  the 
effect  of  shortenmg  the  banded  tooth.  In  such 
a  case  both  incisors  should  be  similarly  treated. 
Some  operators  prefer  to  solder  lugs  to  the  bow, 
which  will  engage  the  incisal  edges  of  the 
centrals,  and  so  prevent  the  displacement  of  the 
bow  to  the  neck  of  the  teeth.  The  writer 
prefers  the  former  method,  as  it  is  neater,  more 
efficient  (preventmg  movement  in  both  direc- 
tions), and  does  not  interfere  with  the  bite  as 
lugs  engagmg  the  mcisal  edges  may  do. 

Precautions  to  hold  the  bow  in  situ  are  less 
necessary  when  inter-maxillary  force  is  bemg 
used,  as  the  tendency  for  it  to  slip  to  the  neck 
of  the  tooth  is  counteracted  by  the  pull  of  the 
rubber  band  in  the  opposite  direction. 

(c)  By  occijjital  anchorage. 

The  appliances  are  arranged  as  they  would 
be  for  (a)  and  (b),  with  the  addition  that  a  knob 
is  soldered  in  the  centre  of  the  bow  that  is  to 
carry  the  teeth  inwards.  This  engages  a  de- 
pression in  the  centre  of  the  cross-bar  of  the 
head-gear,  to  the  extremities  of  which  suitable 
elastic  bands  are  attached,  the  other  ends  of 
the  bands  being  fixed  to  the  skull-cap  (see 
Fig.  328). 


197 


It  will  be  noticed  that  in  the  methods  de- 
scribed for  lingual  movements  of  incisors  there 
is  no  tendency  for  the  molars  and  premolars  of 
the  same  jaw  to  move  forward,  ;".  e.  medially. 
If  it  is  wished  to  move  tliese  medially  as  w  ell  as 
the  incisors  lingually,  rubber  bands  should  be 
stretched  from  the  hook  for  inter-maxillary  force 
to  the  distal  end  of  the  buccal  tube  of  the  same 
side  of  the  same  jaw. 

Movement  obtained  by  means  of  occipital 
ancliorage  may  be  retained  by  light  rubber 
bands  used  in  the  way  just  described  for  moving 
the  molars  medially ;  they  must  not  be  so 
strong  as  to  exert  more  pressure  than  is 
necessary  for  retention,  or  they  will  move  the 
molars,  as  just  referred  to — a  movement  which 
in  all  but  rare  instances  has  to  be  carefully 
guarded  against. 

The  question  of  overbite  enters  largely  into 
consideration  when  upper  incLsors  have  to  be 
moved  lingually,  because  in  many  instances 
this  movement  cannot  be  fully  accomplished 
until  the  overbite  has  been  corrected,  or  prepara- 
tion, by  means  of  a  bite-plate  for  instance,  has 
been  made  to  do  it. 

41.  Removable  Appliances. — Tlie  methods 
that  have  been  described  to  perform  this  move- 
ment are  numerous.  The  followuig  may  be 
regarded  as  among  the  more  efficient. 

(a)  A  platinized  gold  wire  is  fixed  in  a 
vulcanite  plate  and  brought  round  tlie  front  of 
the  incisors,  passing  from  the  palatal  to  the 
buccal  surface  between  the  canine  and  first 
premolar,  or  between  the  first  and  second  pre- 
molars (see  Fig.  307).  [Read  deciduous  molars  [ 
instead  of  premolars  when  necessary.]  Opposite 
the  canine  one  or  two  U -loops  are  made  in  the 
wire,  whicli  should  be  carefully  fitted  to  the  in- 
cisors, so  as  to  come  in  contact  with,  them  at  the 
junction  of  their  middle  and  incisal  thirds ; 
the  same  means  as  \\ere  adopted  in  tlie  case  of 
fixed  appliances  may  be  used  to  keep  the  wire  in 
situ.  (Paragraph  40  (b).)  Care  must  be  taken  in 
bending  the  wire  not  to  allow  its  more  distal 
portions  to  impinge  on  the  soft  tissues.  Move- 
ment is  obtained  by  gradually  closing  the  U-  ! 
springs  on  both  sides,  and  thus  bringing  pressure  I 
on  the  teeth.  AVlieii  the  plate  is  being  inserted, 
the  wire  should  be  placed  over  the  teeth  first, 
and  the  plate  then  carried  into  position.  If  this 
method  is  used  in  combination  with  an  ex- 
pansion plate  the  effect  is  increased,  because 
the  buccal  w  ire  shortens  as  it  widens. 

(6)  Instead  of  a  complete  buccal  wire  with 
U-springs  in  its  course  a  plain  piece  of  wire  may 
be  used.  These  incisors  are  often  much  in- 
clined, and  then  the  wire  should  be  held  in 
position  on  the  tooth  by  means  of  a  spur  or 
notch  on  a  band  on  one  of  the  centrals  (see  Fig. 
315).  When  the  patient  is  accustomed  to  the 
appliance,  the  wire  is  divided  in  the  centre,  and 


bent  so  as  to  exert  s]iring  pressure  on  as  many  of 
the  incisors  as  are  to  be  moved.  If  the  plate  is 
an  expansion  one  it  is  not  essential  to  divide  the 
wire  when  only  slight  hngual  movement  of  the 
centrals  is  reijuired.  More  power  is  obtained 
by  having  a  separate  wire  on  each  side,  the 
left  one  reaching  to  the  right  central  and 
the  right  one  to  tlie  left  central.  These  plates 
may  be  held  in  position  by  crib  clasp-wires 
when  desirable  ;  these  may  be  on  molar,  pre- 
molar, or  deciduous  canine,  or  on  any  tW'O,  on 
one  side  or  both. 

(c)  The    wire,    having    passed    between    the 
teeth,  may  be  cut  off  short,  and  bent  into  a 


Fig.  307. — Badcock  plate  with  buccal  wire,  having 
U -loops,  passing  from  canine  to  canine.  As  the 
plate  is  widened  the  wire  is  drawn  tight  on  the 
labial  surface  of  the  incisors ;  the  pressure  thus 
exerted  may  be  increased  by  closing  the  loops 
of  the  U.  The  plate  is  cut  away  behind  the 
incisors,  or  else  their  lingual  movement  would  be 
impeded ;  it  is  thickened  in  front  to  open  the 
bite  and  shaped  as  an  inclined  plane  to  bring 
the  lower  jaw  forward. 

hook  on  each  side,  so  that  a  rubber  band  may 
be  stretched  from  one  to  the  other  passing 
over  the  labial  surfaces  of  the  anterior  teeth. 
As  it  becomes  necessary  a  smaller  and  smaller 
rubber  band  may  be  used ;  it  is  often  desirable 
to  have  plaui  bands  with  spurs  on  one  or  two 
incisors,  ^^•hich  \\ill  resist  any  tendency  of  the 
band  to  slip  on  to  the  gum  or  off  the  teeth. 
This  apparatus  is  unsiglitly,  but  efficient,  and 
the  patient  can  maniiwlate  it.  Rnbber-dam 
with  the  necessary  holes  punched  in  it  may  be 
used  in  place  of  rubber  bands. 

(f/)  A  fixed  appliance  is  attached  to  the 
incLsors,  arranged  so  that  tension  exerted  from 
a  suitable  point  will  be  transferred  to  all  the 
incisors  ;  for  instance,  a  band  may  be  cemented 


198 


to  one  of  the  centrals,  with  a  labial  wire  extend- 
ing on  each  side  to  engage  the  remaining  in- 
cisors. To  the  palatal  surface  of  the  band  a 
spur  is  soldered,  which  will  support  a  rubber 


Fig.  308. — Vulcanite  plate  and  fi.xed  attaclxment  on  the  right  central  incisors  to 

move  the  two  centrals  lingually. 
Palatal  view  of  the  upper  dental  arch  and  plate  in  position ;    buccal  view  of  the 
two  incisors  and  sectional  view  of  the  former  are  shown. 

1,  Plain  band,  on  the  right  central,  with 

2,  a  spur  directed  incisally  for  the  attachment  of 

3,  a  rubber  band,  which  is  also  attached  to 

4,  a  spur  directed  backwards  in 
6,   the  vulcanite  plate  which  is  held  in  place  by 

5,  the  wire  clasps. 

band  stretched  from  it  to  a  similar  spur  or 
hook  in  the  centre  of  the  palatal  portion  of  the 
plate  (see  Fig.  308).  .Shorter  bands  are  sub- 
stituted as  the  teeth  move.  The  plate  is  held 
in  place  as  already  described  under  (b).  If 
the  rubber  bands  exert  too  powerful  a  pull 
the  plate  will  be  displaced. 

Ill  all  four  methods  the  plate  should  be  cut 
well  back  from  the  palatal  surface  of  the  incisors, 
and  its  edge  carefully  rounded  and  bevelled 
from  the  surface  in  contact  with  the  soft  tissues. 
In  this  way  the  "'  heaping  up  "  of  gum  between 
the  teeth  and  plate  may  be  avoided.  A  zinc 
chloride  mouth-wash  will  assist  in  controlling 
this  condition,  should  it  arise. 


C.  and  D.  Medial  and  Distal  Movement  of  Incisors 
42.  Fixed  Appliances. — Anchorage :  Simple 
or  Reciprocal;  either  may  be  Inter-maxillary. 
These  two  movements  are  taken  together, 
as  they  both  indicate  movement  along  the 
line  of  tlie  dental  arch,  the  one  towards  and 
the  other  away  from  the  median  line.  Simple 
ligaturing  of  a  tooth  to  the  bow  is  insufficient 
to  effect  these  movements ;  it  is  necessary  to 
obtain  a  fixed  point  on  the  bow  (see  Fig.  309), 
preferably  for  each  tooth,  to  which  the  tooth 
may  lie  moved  by  simply  including  in  one  liga- 
ture the  tootli  and  fixed  point.  This  alone  is 
sufficient  to  effect  the  desired  movement, 
which,  however,  may  be  increased  by  means 
of  the  nuts  engaging  the  buccal  tubes ;  the 
nut   away   from    wliich    tooth    movement     is 


desired  Ls  turned  at  intervals,  so  that  the  action 
of  the  ligatures  may  be  increased  by  means  of 
the  spring  of  the  bow,  which  is  now  also  working 
as  a  jack-screw.  The  fixed  points  on  the  bow 
are  obtained  either  by 
filing  notches  m  the  rib 
of  a  ribbed  bow,  or  by 
soldering  spurs  to  the 
bow  as  described  on  p. 
225.  Any  number  of 
teeth  may  be  moved  in 
this  way,  so  long  as  the 
anchorage  (simple  at  the 
molar)  is  sufficient. 

As  an  auxiliary  in 
assisting  this  movement, 
inter-maxillary  force  may 
be  made  available  by 
stretching  a  rubber  band 
from  the  pomt  where  the 
greatest  force  is  desired 
to  a  suitable  point  in  the 
opposite  jaw,  where  all 
the  teeth  should  be  liga- 
tured to  the  bow  in  order 
tliat  the  necessary  an- 
chorage may  be  obtained 
(see  Fig.  309). 
43.  Removable  Appliances.  —  Anchorage: 
Simple ;  teeth  and  hone  via  plate.  Where 
several  teeth  have  to    be  moved  medially  by 


Fig.  309. — Medial  and  distal  movement  of  incisors. 

1.  Upper  bow. 

2.  Lower  bow. 

3.  Spur  on  (1)  for  attachment  of  (8),  a  rubber  band 

to  exert   force  laterally  on  the  upper   bow,    and 
through  it  on  the  teeth. 

4.  Spur  for  attachment  of  rubber  band  on  (2). 

5.  Spurs   on    upper  bow   for   attachment  of  ligatures 
(fi)  to  exert  lateral  force  directly  on  to  the  teeth. 

Wire  ligatures  attaching  teeth  to  upper  bow. 
Wire  ligatures  attaching  teeth  to  lower  bow. 
Dotted   line   to   show    position   of    median    line    of 

mouth,  with  which   the   space   between   the    two 

upper  centrals  should  coincide. 


0 


9 


means  of  a  removable  appliance,  a  fixed  point 
must  be  obtained  on  one  of  them  and  on  the 
plate.  From  the  latter  a  platinized  gold  wire 
passes  to  the  buccal  sulcus  near  the  point  to 


199 


uhich  the  teeth  are  to  be  brought,  yet  the  two 
points  must  be  sufficiently  far  from  one  another 
that  a  rubber  band  stretched  between  tlie  two 
will  exert  tension  (see  Fig.  310).  The  wire  is 
bent  towards  the  necks  of  the  teeth  and  then 
into  a  hook,  which  is  directed  away  from  the 
teeth  to  be  moved  ;  this  hook  is  to  carry  the 
rubber  ligature.  For  the  tooth  most  distant 
(of  those  to  be  moved)  from  this  hook,  a  plain 
band  is  made,  which  will  also  carry  a  rubber 
ligature  by  means  of  a  spur  near  the  neck  of 
the  tooth  ;  this  spur  is  directed  away  from  the 
hook.  A  rubber  band  is  now  stretched  from 
the  hook  to  the  spur.  This  pulls  the  teeth 
towards  the  anchorage  obtained  from  the  plate  ; 
it  also  tends  to  move  the  intervening  teeth 
palatally,  but  this  is  avoided  by  having  the 
vulcanite  plate  fit  close  up  to  them.  The  edge 
of  the  vulcanite  plate  sliould  be  well  rounded 
and  present  an  unl)roken  line,  so  that  it  guides 
the  teeth ;  they  then  move  along  it  without 
difficulty. 

Incisors  can  also  be  moved  medially  or  distally 
by  means  of  ordinary  coil  springs  arranged  to 
engage  the  appro.ximal  surfaces  of  the  teeth, 
as  may  be  necessary.  The  application  of  such 
an  appliance  is  limited  by  the  number  of  teeth 
to  which  the  necessary  force  can  be  efficiently 
applied. 

E.  (i)  Depression  in  both  Jaws  simultaneously 

44.  Fixed  Appliances. 
Anchorage :  (a)  Simple  from  the  molars. 
(6)  Reciprocal. 

(a)  Wlien  the  bow  is  being  fitted,  it  is  bent  to 
rest  over  the  alveolar  process  rather  than  over  the 
necks  of  the  teeth  (see  Fig.  311).  Ligatures  are 
then  applied  to  all  the  incisors,  care  being  taken 
that  in  so  doing  the  bow  is  pulled  as  low  down 
as  possible,  i.e.  the  bow  is  sprung  from  its  position 
of  rest,  and  the  teeth  are  holding  it  in  its  new- 
position,  but,  being  movable,  they  cannot  hold  it 
there  permanently  ;  the  spring  of  the  bow  grad- 
ually overcomes  the  resistance  of  the  tissues, 
and  then  the  bow  slowly  regains  its  old  position, 
carrying  the  teeth  with  it,  that  is,  the  teeth 
are  depressed  in  their  sockets  (see  Fig.  287  (/) 
and  {g) ).  It  will  be  noticed  that  the  position 
of  the  ligature  on  the  tooth  must  remain 
constant,  ai:d  it  is  probaljle  that  the  bow 
will  drag  the  ligature  over  the  cingulum  and 
neck  of  the  tooth,  rather  than  depress  the 
tooth  in  its  socket.  To  obviate  this,  the  teeth 
to  be  depressed  are  banded,  and  spurs  directed 
towards  the  incisal  edge  are  soldered  to  their 
lingual  surfaces ;  as  the  ligature  passes  round 
tlie  tooth  it  is  caught  beneath  the  spur,  so  that 
the  spring  of  the  bow  is  now  definitely  brought 
to  bear  on  the  teeth.  Any  tendency  for  the 
molars  to  be  elongated  nnist  be  combated  by 


increasing  the  anchorage,  which  is  done  by 
putting  spurred  bands  on  the  premolars  and 
arranging  that  if  there  is  any  elongation  of  the 
molars  it  would   be  shared   by  the  premolars, 


-v^' 


Fig.  310. — A  vulcanite  plate  and  fixed  attachments 
on  the  incisors  to  move  them  laterally,  those  on 
the  right  medially  and  those  on  the  left  distally. 

On  the  right  lateral  and  left  central  are  plain  bands 
with  spurs,  from  which  rubber  bands — providing 
the  force  to  move  the  teeth — are  stretched  to  the 
hook  that  passes  from  the  plate  between  the  left 
premolars. 

The  right  lateral  will  also  move  the  right  central 
and  the  left  central  the  left  lateral.  The  plate 
is  left  in  contact  with  tlio  lingual  surfaces  of  the 
incisors,  so  that  they  will  not  be  moved  lingually 
by  the  pressure  of  the  rubber  bands ;  but  the 
edge  of  the  plate  must  present  an  even  line  so 
that  the  teeth  will  pass  along  it. 

the  bow  engaging  the  spurs  direct  or  tlirough  the 
medium  of  ligatures. 

If  it  isnot  necessary  to  have  the  teeth  under 
separate  control,  spurs  projecting  at  right  angles 


KiG.   311. — Shows    the    wire    bow    and    plain    bands, 

with  notch,   on   the   central  arranged   to  depress 

the  incisor  in  its  socket. 
The     dotted    line    shows    the    bow    at    rest,    and    to 

make  it  an  active  force  it  is  pulled  down  to  rest 

in  the  notch  on  the  plain  band. 

from  the  labial  surface  of  the  bands  on  the 
incisors  are  arranged  so  as  to  engage  the  bow 
when  it  is  sprung  towards  the  incLsal  edges  of 
the  teeth  :  agahi  the  force  is  transferred  direct 
from  the  bow  to  tlie  teeth.     Instead  of  soldering 


200 


spurs  to  the  labial  surface  of  the  bands,  the 
seam  of  the  band  may  be  made  on  the  most 
prominent  part  of  tlie  labial  surface  of  the 
tooth  and  left  projecting ;  a  notch  is  then  cut 
in  the  seam  into  ^\hich  the  bovv  will  just  fit 
(see  Fig.  315,  reversed);  the  upper  arm  of  the 
notch  takes  the   place    of   the    spur  and  con- 


FiG.  312. — Bows  and  accessories  to  depress  the  upper 
and  lower  incisors  in  their  sockets. 

Plain  bands  on  all  incisors ;  to  one  a  labial  wire  is 
soldered  engaging  spurs  incisally  on  the  other 
three  bands ;  to  this  labial  wire  spurs  are 
soldered  for  the  attachment  of  rubber  bands  to 
exert  inter-maxillary  force,  the  upper  and  lower 
bows  intervening,  as  shown.  Rubber  bands 
may  also  be  used  to  effect  medial  or  distal  move- 
ment of  any  of  the  incisors,  as  shown,  and  this 
movement  may  be  assisted  by  turning  that  nut 
against  the  buccal  tube  away  from  which  the 
tooth  lias  to  move.  Spurs  on  the  buccal  wire 
or  bands  at  its  extremities  may  be  employed 
to  prevent  any  lateral  movement ;  spin's  may 
also  be  used  to  include  another  tooth  in  the 
medial  or  distal  movement — one  to  which  the 
rubber  band  is  not  directly  attached. 

sequently  should  be  left  longer ;  it  is  then  better 
able  to  support  the  springy  bow. 

(b)  Reciprocal  Anchorage.  Clamp-bands  on 
first  molars. 

The  bow,  not  less  than  gauge  16  (B  and  S), 
is  bent  to  pass  across  the  alveolar  process  in  both 
jaws,  and  the  premolars  and  canines  are  firmly 
ligatured  to  it.  All  four  incisors  must  be  banded, 
and  attachments  soldered  to  them  whereby  all 
the  teeth  wUl  move  equally,  although  force  is 
applied  at  only  one  or  two  points.  The  manner 
in  which  the  band  attachments  are  arranged 
may  be  as  follows,  though  equally  efficient 
modifications  will  suggest  themselves  to  the 
thoughtful  operator. 

To  the  band  on  one  of  the  centrals  a  labial 
wire  is  soldered  so  as  to  pass  across  the  labial 
surfaces  of  the  remaining  incisors ;  in  doing 
so  it  should  engage  spurs  on  bands  on  the 
remaining  incisors  just  long  enough  to  receive 
the  force  transmitted  through  the  labial  wire ; 
if  there  is  any  tendency  for  the  laterals  to  move 
distally,  it  may  be  counteracted  by  giving  the 
wire  an  inclination  towards  the  gingival  margin. 


or  a  rectangular  bend  may  be  given  to  it 
(see  Fig.  312). 

Similar  appliances  are  made  for  both  jaws, 
and  then  rubber  bands  are  stretched  from  the 
labial  wii-e  at  points  between  the  upper  laterals 
and  centrals  to  corresponding  points  on  the 
appliance  on  the  lower  teeth.  The  rubber  bands 
may  be  slipped  over  the  ends  of  the  horizontal 
or  buccal  wire  and  past  any  spurs,  by  stretching 
it,  to  the  desired  point ;  it  is  attached  m  both 
jaws  in  the  same  manner,  the  two  wire  bows 
intervening ;  another  method  of  attachment  of 
the  rubber  bands  is  by  looping  it  at  one  end 
on  to  one  buccal  wire  and  at  the  other  catching 
it  on  a  special  spur  (see  Fig.  312)  directed 
towards  the  incisal  edges  of  the  teeth. 

If  it  is  desired  to  move  any  of  the  teeth 
medially  or  distally  at  the  same  time,,  it  can  be 
done  by  rubber  bands  passing  from  the  spurs 
on  the  teeth  to  the  bow  (simple  anchorage), 
or  to  other  teeth — incisors  or  premolars — ,when 
the  anchorage  would  be  simple  or  reciprocal, 
according  to  the  arrangement  of  rubber  bands 
adopted.  The  band  to  which  the  labial  wire 
is  soldered  should,  for  preference,  be  on  a  tooth 
that  has  not  to  move  medially  or  distally.  A 
rubber  band  from  one  lateral  to  another  would 
move  each  equally  (reciprocal  anchorage),  un- 
less one  were  in  contact  with  a  central,  when 
the  anchorage  would  be  reinforced,  the  latter 
tooth  taking  little  or  no  part  in  the  movement ; 
if  it  w  ere  necessary  to  make  this  anchorage  more 


Fig.   313. — A    variation    of     the    appliance   shown    in 

Fig.  312,  to  depress  teeth  in  their  sockets. 
(a)  Plain  band  on  left  central  to  which  is  soldered 
(6)  a  labial  wire  terminating  at 

(c)  as  hooks  to  engage  the  incisal  edges  of  the  incisors, 
(d!)  An  extension  soldered  to  (6)  to  engage  the  right 

central  just  as  (c),  (o)  engage  the  laterals, 
(e)  Spur  on  (6)  for  the  attachment  of 
(g)  a  rubber  band  to  exert  inter-maxillary  force.     In 

passing  to  be  attached  on  the  lower  bow  it  passes 

over 
(/)  the  upper  wire  bow. 

secure,  it  could  be  done  by  soldering  vertical 
spurs  to  the  labial  wire  in  such  a  way  that 
they  engage  the  spurs  on  the  bands,  and  thus 
prevent  the  movement  laterally  of  individual 
teeth  (see  Fig.  312).  Instead  of  soldering 
spurs  to  the  bands,  the  seam,  placed  labially, 
can  be  left  long,  and  cut  so  as  to  act  as  the 
spur. 


201 


If  the  bite  permits  a  wire  or  similar  attach- 
ment to  engage  tlie  incisal  edge  of  any  of  the 
teeth,  a  band  may  be  dispensed  with  on  tliat 
tootli  (the  appliance  cannot  be  constructed 
without  one  band).  To  secure  this  the  labial 
\x  ire  iis  brought  half-way  across  the  tooth  and 
then  given  a  rectangular  bend,  so  as  to  pass  to 
its  incLsal  edge ;  it  is  bent  sharply  on  itself  so 
as  to  engage  the  incLsal  edge  of  the  tooth  (see 
Fig.  313);  both  ends  of  the  wire  are  similarly 
arranged ;  if  an  intervening  tooth  Ls  to  be  dealt 
with  in  this  May,  a  piece  of  wire  is  soldered  to 
the  labial  wire  so  as  to  extend  to  the  incisal 
edge  of  the  tooth  and  then  engage  it. 

45.  Removable  Appliances. — Anchorage  : 
Simple.  {Teeth  and  bone  via  plate.)  The  in- 
cisors may  be  depressed  in  their  sockets  by  a 
platinized  gold  wire  passing  across  the  labial 
surfaces  of  the  incisors ;  it  is  attached  in  the 
palate  of  the  vulcanite  plate,  and  passes 
to  the  buccal  aspect  either  between  the  pre- 
molars, or  first  premolars  and  canines.  The 
wire  must  exert  pressure  on  the  crown  of  the 
tooth  in  tlie  direction  of  the  root,  and  for  this 
purpose  lugs  should  be  soldered  to  it,  which 
will  engage  the  incisal  edges  of  the  teeth  to  be 
depressed  (see  Fig.  357) ;  they  may  be  made  of 
wire  or  plate.  As  an  alternative  to  the  lugs, 
which  might  be  impracticable  in  the  case  of  a 
very  close  bite,  ])lain  bands  should  be  made 
for  and  cemented  to  the  teeth  to  be  depressed, 
bearing  on  their  labial  aspect  spurs,  which  the 
labial  wire  will  engage  on  their  incisal  aspect 
when  it  is  at  rest.  Tliat  tlie  plate  may  be 
absolutely  stable  it  should  be  made  on  a  model 
from  a  plaster  impression,  and  be  held  in  situ 
by  four  w  ire  crib-clasps  on  the  fii'st  permanent 
molars  and  first  premolars. 

Tlie  labial  wire  at  rest  now  engages  the  spurs 
on  the  bands  on  the  teeth  ;  the  plate  is  removed 
from  the  mouth,  and  the  wire  is  bent  towards 
the  roots  of  the  teeth,  and  the  plate  replaced, 
so  that  the  wii'e  occupies  the  same  relation  to 
the  teeth  as  previously,  but  now  exerts  pressure 
on  those  teeth  through  the  spurs  to  depress 
them.  The  pressure  is  increased  from  time  to 
time  until  the  desired  movement  has  taken  place. 

E.  (ii)  Depression  in  one  Jaw  only 

46.  Fixed  Appliances. — Anchorage:  Simple. 
Tliis  movement  is  obtained  as  described  in 
paragraph  44.  The  arrangement  described  at 
the  end  of  paragraph  44  (6)  may  also  be  used, 
the  bow  engagmg  a  spur  on  the  one  band  that 
is  fitted. 

47.  Removable  Appliances. — Exactly  as  in 
paragraph  45. 

F.  (i)  Elongation  in  both  Jaws  simultaneously 

48.  Fixed  Appliances. — Anchorage  :  Simple 


of  depression,  which  has  just  been  described, 
and  is  accomplished  in  a  similar  but  reverse 
mamier.  Li  this  case  the  bow  is  bent  to  rest 
at  or  beyond  the  incisal  edge  of  the  incisors. 
The  latter  are  then  securely  ligatured  to  the  bow, 
which  at  the  same  time  is  pulled  up  so  as  to  rest 
on  a  level  with  the  necks  of  the  teeth  (see 
Figs.  314,  287  {(l)  and  (e)).  The  spring  of  the 
bow,  which  is  tending  to  return  to  its  original 
position,  causes  the  movement  of  the  teeth. 


Fig.   314. — Cross-section  of  an  incisor  with  wire  bow 

in  position  to  elongate  it. 
(a)  Cross-section  of  incisor. 
(6)  Cross-section  of  wire  bow  at  rest. 

(c)  Cross-section  of  wire  bow  pulled  up  into  position 

at  the  neck  of  the  tooth  by 

[d)  the  wire  ligature. 

The  arrow  indicates  tlie  direction  of  movement  of  the 
tooth  due  to  the  effort  of  the  bow  to  return  to  its 
position  of  rest. 

It  will  be  observed  that  the  ligatures  may 
not  be  held  securely  at  the  neck  of  tlie  teeth, 
and  these  should,  therefore,  have  plain  bands, 
with  spurs  at  tlie  cervical  edge  directed  root- 
wards,  cemented  to  them.  The  ligatures  are 
then  passed  round  the  tooth,  being  held  in 
position  on  the  cervical  aspect  of  the  spur. 
By  this  method  the  operator  has,  in  addition, 


and  Reciprocal. 
7* 


This  movement  is  the  reverse 


Fig.  315. 

(a)  Plain  band  for  an  incisor. 

(b)  Seam  of  the  band. 

(c)  Notch  cut  in  the  seam  to  support 

(d)  bow  or  labial  wire,  which  is  to  exert  force  towards 

(6). 

control  of  both  labial  and  lingual  movements 
of  individual  teeth.  If  this  additional  control 
is  unnecessary,  or  not  desired,  the  teeth  to  be 
elongated  are  banded  as  before,  but,  instead  of 
spurs  being  soldered  to  the  lingual  aspect  of 
the  bands,  the  seam — which  lias  been  made 
on  the  labial  surface — should  be  cut  so  as  to 
form  a  sjjur,  on  the  gingival  aspect  of  wliich 
the  bow  may  rest  (sjc  Fig.  315).  Lingual 
movement   of    the    incisors  is  pos.sible   at  the 


202 


same  time  as  elongation  when  the  appliances 
are  adjusted  in  this  way. 

This  movement  (elongation)  may  be  increased 
by  the  reciprocal  action  of  inter-maxillary  force, 
one  or  tv  o  rubber  bands  being  used  between  the 
two  jaws.  To  attach  these,  spurs  are  soldered 
to  the  bows,  opposite  the  approximal  surfaces 
of  the  centrals  and  laterals  ^^•hen  two  rubber 


Fig.  316. — Fixed  appliance  arranged  to  elongate 
incisors. 

(a)  Tlie  wire  bow  to  which  is  soldered 

(b)  a  spur  for  the  attachment  of 

(g)  rubber     bands     to     exert     inter-maxillary     force, 

attached  also  to 
(/)■  a  spur  on 
(e)   the  lower  bow. 

(c)  Plain  bands  with 

(d)  spurs  to  be  engaged  on  the  gingival  aspect  by  (a), 

whence  the  force  is  transmitted  to  the  teeth. 

bands  are  to  be  used,  and  between  the  U\o 
centrals  when  only  one  is  needed  (see  Fig.  316). 
These  spurs  slioidd  be  straight  lengths  of  wire 
attached  to  the  bow  at  right  angles  and  pro- 
jecting into  the  labial  sulcus ;  their  length 
need  only  be  sufficient  to  prevent  a  rubber 
band  jumping  off.  The  rubber  bands  should 
be  worn  continuously  except  during  meals ; 
when  they  are  stretched  from  the  canine  to 
the  molar  region,  there  is  no  need  to  remove 
them  except  for  cleansing  the  teeth  and 
renewal. 

It  is  possible  to  apply  force  to  an  incisor  to 
elongate  it  without  the  intervention  of  a 
cemented  band,  though  not  with  very  satis- 
factory results.  A  wire  ligature,  gauge  24  or 
26,  is  tied  tightly  round  the  neck  of  the  tooth 
to  be  elongated,  being  made  as  secure  as  possible. 
Then  the  free  ends  are  used  to  ligature  the  tooth 
to  the  bow,  -which,  in  so  doing,  is  pulled  up  to 
the  necks  of  the  teeth  from  the  incisal  edges. 
The  spring  of  the  bow  causes  it  to  exert  force 
to  return  to  its  original  position ;  this  force  is 
transmitted  through  the  wire  ligature  to  the 
tooth,  which  is  thus  pulled  downwards  in  the 
upper  jaw  and  upwards  in  the  lower. 

49.  Removable  Appliances. — As  in  the  case 
of  fixed  appliances,  accessories  must  be  securely 
fixed  to  the  teeth  to  be  moved,  whereby  the 
force  may  be  transmitted  to  them.     Force  in  a 


vertical  direction  camiot  be  applied  direct  to 
the  teeth  them.selves  (when  removable  appli- 
ances are  used) ;  the  simplest  method  to  adopt 
is  that  already  described  in  paragraph  48 — bands 
cemented  to  all  the  incisors  to  be  moved,  such 
bands  having  labial  seams  cut  to  form  a  spur, 
which  may  be  engaged  by  a  buccal  wire.  If  it 
is  desired  to  solder  a  spur  to  the  band,  this  may 
be  done ;  in  that  case  the  seam  may  be  placed 
lingually.  The  spur  should  be  a  straight  piece 
of  wire  soldered  at  right  angles,  or  with  a  slight 
inclination  gingivally,  to  the  labial  surface  of 
the  band,  and  just  long  enough  to  be  engaged 
by  the  bow  attached  to  the  plate  without 
the  possibility  of  the  wire  bow  slipping  past  it. 
All  these  free  ends  of  wire  should  be  care- 
fully rounded  and  smoothed  to  obviate  any 
irritation  of  the  soft  tissues  due  to  movement 
over  them. 

The  removable  appliance  itself  consists  of  a 
vulcanite  plate  to  which  a  buccal  wire  is  at- 
tached ;  this  wire  issues  from  the  palatal  surface 
of  the  plate  between  the  two  premolars ;  from 
its  attachment  to  just  beyond  the  first  bend  as 
it  turns  to  pass  over  the  buccal  surfaces  of  the 
teeth  it  should  be  considerably  strengthened ; 
this  may  be  done  by  burnishing  thin  platinum 
foil  on  to  the  teeth  just  where  the  wire  passes 
across  them  and  uniting  the  two  with  solder. 
To  increase  the  spring  of  the  wire  it  should  be 
looped  in  the  neighbourhood  of  the  canine,  the 
loops  being  parallel  A\ith  the  general  direction 
of  the  wire  as  shown  in  Fig.  317.     This  labial 


Fig.   317. — Removable  appliance  to  elongate  incisors, 
(a)  Vulcanite  plate  passing  from  which,  between  the 

premolars,  is 
(6)  a  spring   to   exert  force  incisally  on  the  central, 

througli 
(tl)  a  spur  on 
(c)  a  plain  band. 
A  cross-section   of   the   central  with  band  and  spring 

in  position  is  also  shown. 

wire  is  adjusted  to  rest  on  the  gingival  aspect 
of  the  spurs  on  the  labial  surface  of  the  bands 
on  the  incisors;  this  having  been  done,  the 
wire,  by  means  of  its  looped  portion,  is  bent  in 
the  direction  of  the  cutting  edges  of  the  teeth, 
so  that  it  rests  beyond  them  ;  great  care  must 
be  taken,  in  making  this  bend,  not  to  disturb 
the  wire  in  the  least  behind  the  loop,  or  its 
accurate    fit    in   the    premolar   region   will    be 


.203 


disturbed.  Movement  of  the  teeth  is  now 
controlled  entirely  by  the  amount  of  spring 
given  to  the  buccal  wire.  Clasps  are  neces- 
sary to  retain  the  plate,  as  the  spring  of  the 
buccal  wire  tends  to  displace  it.  On  a  low  er  plate 
cleats  should  be  arranged  to  engage  the  lingual 
sulcus  of  the  first  permanent  molar  to  jjrevent 
the  plate  being  forced  dow  n  into  the  soft  tissues. 

F.  (ii)  Elongation  in  one  Jaw  only 

50.  Fixed  Appliances. — This  movement  is 
brought  about  in  exactly  the  same  way  as 
described  in  paragraph  48,  when  it  is  produced 
in  both  jaws  simultaneously,  except  that  when 
inter-maxillary  force  is  used  the  anchorage, 
instead  of  being  reciprocal,  must  be  simple, 
i.  e.  the  teeth  of  one  jaw  are  used  as  anchorage 
to  move  the  four  incisors  of  the  opposite  jaw. 

51.  Removable  Appliances. — Paragraph  49 
describes  this  movement  for  each  jaw  separately, 
and  it  applies  exactly  to  this  movement. 

G.  Rotation 

52.  Fixed  Appliances. — E.  H.  Angle  de- 
scribes a  method  of  rotating  simultaneously 
two  approximal  incisors  whose  inwardly  turned 
corners  are  contiguous.  A  section  of  wire, 
gauge  15  (B.  &  S.),  and  in  length  aboiit  one- 
third  the  combined  width  of  the  teeth  to  be 
rotated,  is  soft-soldered  to  a  brass  wire  ligature. 
The  wire  is  placed  on  the  lingual  surface  of  tlie 
teeth  to  be  rotated  and  the  ligature  passed 
through  the  inter-proximal  space,  one  end 
being  above  and  the  other  below  the  bow ; 
the  ligature  is  then  tightly  tied,  and  the  in- 
standing  comers  are  gradually  pulled  out. 
The  rapidity  of  movement  may  be  hastened 
by  stretching  a  strip  of  rubber  between  the 
bow  and  the  outstanding  corners. 

It  is  believed  that  rotation  of  the  teeth 
individually  will  be  found  to  be  more  satis- 
factory for  these  reasons  :  (1)  the  wire,  in 
order  to  be  effectual,  nuist  rest  against  the 
flattened  and  wider  portion  of  the  incisor 
teeth,  i.  e.  nearer  the  incisal  edge  than  the 
cervical,  where  the  bow  rests ;  tlie  tendency 
then  is  for  the  bow  to  be  displaced  from  its 
position  of  greatest  efficiency  w  hen  the  ligature 
is  tied ;  (2)  if  the  wire  is  placed  near  the  neck 
of  the  tooth  so  that  the  ligature  will  not  dis- 
place the  bow,  then  the  efficiency  of  the  wire 
is  much  impaired,  because  it  bears  against  a 
narrower  and  rounded  part  of  the  tooth.     (For 


description  of  another  appliance  for  rotating 
incisors  see  p.  158). 

53.  Removable  Appliances. — Removable 
appliances  are  not  well  adapted  for  the  rotation 
of  teeth,  but  they  will  bring  about  this  move- 
ment in  suitable  cases.  Such  a  one  is  that  in 
which  the  distal  corners  of  two  centrals  are 
outstanding ;  a  labial  w  ire  constantly  exei-ting 
pressure  on  these  corners,  behind  which  the 
plate  has  been  cut  away,  whilst  the  medial 
corners  are  held  in  position  by  the  vulcanite 
against  the  lingual  surfaces,  will  slowly  rotate 
the  two  teeth.  It  must  be  remembered  that  a 
rotated  tooth  occupies  less  space  in  the  arch 
than  one  in  normal  alignment ;  it  is,  there- 
fore, essential  that  room  be  made  for  the  tooth 
when  normally  placed  before  the  operation  of 
rotation  is  undertaken,  or  at  least  that  room 
be  made  as  the  tooth  rotates. 

With  some  forms  of  appliance  the  two 
movements  assist  one  another.  As  an  in- 
stance of  this  one  may  refer  to  the  case  of 
an  upper  jaw  that  is  too  narrow,  especially  in 
the  canine  region,  and  in  which  the  incisors 
protrude,  the  centrals  being  rotated  so  that 
their  distal  corners  are  outstanding,  and  all 
the  teeth  being  in  contact  with  one  another. 
Such  a  case  may  be  treated  by  widening  the 
upper  teeth — from  canine  to  molar  included ; 
as  the  canine  moves  outward  the  laterals  will 
go  with  it — so  that  the  laterals  become  more 
separated,  in  this  way  making  room  for  the 
centrals,  which  are  being  rotated  by  a  labial 
wire.  This  wire  passes  from  the  palatal  surface 
of  the  plate  between  premolars,  or  first  pre- 
molar and  canine,  on  one  side,  to  be  similarly 
attached  on  the  other ;  it  may  have  loops  in 
its  course  opposite  the  canines  whereby  the 
amount  of  pressure  on  the  centrals  can  be  con- 
trolled ;  this  is  not  essential,  as  the  widening 
of  the  plate  has  the  eflFect  of  shortening  the 
wire,  and  if  this  did  not  suffice,  the  course  of 
the  wire,  instead  of  being  allowed  to  remain 
straight  or  direct,  may  be  made  sinuous  or 
indirect  by  bending  with  pliers. 

By  one  of  these  methods  pressure  is  exerted 
on  the  outstanding  comers  of  the  centrals ; 
the  plate  is  made  as  described  at  the  beginning 
of  this  paragraph  (53) .  The  widening  movement 
of  the  laterals  may  in  some  cases  be  assisted  by 
the  pressure  of  the  distal  corner  of  the  central  on 
their  medio-buccal  corners,  which  are  prevented 
from  moving  inwards  by  the  vulcanite  liehind 
them. 


CHAPTEE   VIII 


ABNORMALITIES   OF   POSITION— TREATMENT   [continued) 


INDIVIDUAL   TOOTH   MOVEMENTS 

Molars. 


II.  Premolars. 
III.  Canines. 


IV.  Incisors. 


I  A.  Buccal. 

B.  Lingual. 

C.  Medial. 

D.  Distal. 

E.  Depression. 

F.  Elongation. 

G.  Rotation. 


Appliances. 

(1)  Fixed. 

(2)  Remov- 

able 


I  MOLARS 
A.  Buccal  Movement 
(1)  Fixed  Appliances. — (a)  With  the  damp- 
hands  on  the  molars.  This  is  done  by  means  of 
simple  anchorage.  The  buccal  tube  (permitting 
tilting  movement)  on  the  band  on  the  tooth  to 
be  moved  should  be  a  round  one,  and  the  lingual 
clamping  wire  shoidd  not  be  allo\\ed  to  come 
in  contact  with  the  lingual  surface  of  any  of  the 
teeth.  On  the  opposite  side,  the  buccal  tube 
should  be  one  that  permits  of  translational 
movement  in  preference  to  one  that  admits  of 
a  tilting  movement  of  the  molar ;  tlie  clamping 
wire  should  be  in  contact  with  the  lingual  sur- 
face of  the  approximal  tooth,  and  all  the  teeth 
on  this  side,  in  front  of  these  two,  should  be 
ligatured  to  the  bow  after  it  has  been  bent  to 
fit  closely  to  them.  Before  the  bow  is  fuially 
put  in  tlie  tubes  and  the  teeth  are  ligatured  to 
it,  spring,  sufficient  to  accomplish  the  desired 
tooth  movement,  is  given  to  the  bow  by  pulling 
its  ends  apart.  In  this  ^^•ay  six  or  seven  teetli 
on  one  side  are  used  as  anchorage  to  move  one 
tooth  on  the  other  side. 

(6)  With  the  clamp-bands  on  the  second  pre- 
molars. The  clamping  ^\  ire  should  be  directed 
backwards,  and  arranged  by  adjustment,  and 
bending  if  necessary,  to  lie  against  the  neck  of 
the  molar  tooth  to  be  moved ;  but  for  its 
attachment  to  the  secand  premolars,  the  bow  is 
arranged  exactly  as  in  (a),  except  that  the  pre- 
molars and  canines  on  both  sides  are  ligatured 
to  it,  and  it  lias  no  spring.  A  piece  of  rubber 
is  now  stretched  between  the  clamping  ^^•ire 
and  molar  to  be  moved.  (If  the  same  arrange- 
ment of  the  clamp-band  is  adopted  on  the  other 
side  it  should  be  in  contact  \\ith  the  tooth.) 
The  effect  of  the  rubber  is  to  move  the  molar 
buccally,  the  premolars  and  canine  remaining 
stationary,  because  their  combined  resistance 
is  greater  than  that    of    the    molar.     Simple 


anchorage  is  now  used  in  another  form  to  move 
the  molar  buccally,  it  being  this  time  the  total 
of  the  resistance  of  the  first  and  second  pre- 
molars and  canine  to  lingual  movement,  in 
addition  to  the  resistance  that  the  bow  offers 
to  its  extremities  being  made  to  approximate 
one  another. 

(c)  Buccal  movement  of  molars  may  also  be 
brought  about  by  inter-maxillary  force ;  a 
rubber  band  is  fixed  to  the  lingual  surface  of 
the  clamp-band  through  the  medium  of  a  spur 
cervically  inclined,  and  is  stretched  thence  to 
the  buccal  surface  of  the  corresponding  tooth  in 
the  opposite  jaw  (s3e  Fig.  290).  With  appliances 
so  arranged,  tooth  movement  would  be  recipro- 
cal, so  a  buccal  wii'e  or  bow  mugt  be  arranged  to 
augment  the  resistance  of  the  tooth  not  to  be 
moved ;  the  buccal  wire  or  bow  should  be  bent 
to  touch  the  two  premolars  and  canines,  to 
which  it  may  be  ligatured  to  give  it  greater 
stability.  If  the  second  molar  has  erupted  the 
buccal  wire  should  be  extended  to  engage  this 
tooth  also.  It  must  be  remembered  that  there 
is  a  tendency  for  the  molars  to  elongate  by  this 
method. 

Methods  («)  and  (c)  may  be  combined. 

(2)  Re.movable  Appliances. — A  powerful 
coil  sj)ring  acting  on  the  lingual  surface  of  an 
upper  molar  will  move  it  buccally ;  on  account 
of  the  convexity  and  slope  of  the  surface  on 
which  it  is  to  act,  there  is  every  probability 
that  the  spring  will  not  exert  its  force  just 
where  it  is  needed ;  to  overcome  this  difficulty 
means  should  be  adopted  to  make  this  surface 
vertical,  or  to  give  it  such  a  slope  as  will  prevent 
the  spring  slipping  off.  This  is  done  by  means 
of  a  band,  which  is  thickened  by  the  addition  of 
solder  to  give  it  the  necessary  shape  ;  or  a  spur 
may  be  soldered  to  the  lingual  surface  of  the 
band  so  as  to  retain  the  active  arm  of  the  spring 
in  the  desired  position.  The  band  must,  of 
course,  be  cemented  to  the  tooth ;  a  plain 
soldered  band  serves  the  purpose  well ;  the 
size  of  the  tooth  may  be  obtained  by  means  of 
Herbst's  bands  used  for  measuring  roots  tha  ' 
are  to  be  crowned.  Three  or  four  clasps  she  ■'''® 
be  used  to  hold  the  plate  in  position,  or  r 
po^\erful  spring  will  dislodge  it. 

The   same  method   may  be  adopt 
case  of  a  lower  molar,  except  that  a 
necessary   to    hold   the   arm   of 


.it  in 
teeth, 
,  .tre  must 
to  disturb 
looji,  or  its 


position,  but  more  clasps  are      region    will    be 


204 


205 


the  plate  securely.  Two  at  least  are  essential 
on  the  same  side  as  the  Sf)ring ;  they  must  em- 
brace the  buccal  surfaces  of  the  teeth  well,  so 
that  the  spring  does  not  displace  the  plate 
lingually. 

Another  method  is  by  means  of  a  jack-screw,  ' 
one  end  of  which  acts  directly  on  the  tooth 
to  be  mo\-ed,  ^^■hilst  the  force  at  the  other  end 
of  the  screw  is  received  by  several  teeth,  whose 
combined  resistance  affords  the  simple  anchorage 
for  the  movement  of  the  one  molar.  Either 
fixed  appliances  or  a  \ailcanite  plate  may  afford 
the  support  for  the  jack-screw,  whose  force 
should  be  delivered  to  the  tooth  indirectly,  i.  e. 
through  the  medium  of  a  band  arranged  to 
ensure  that  the  force  shall  be  delivered  in  such 
a  way.  that  it  will  do  the  required  \\ork. 

A  screw  in  a  vulcanite  plate,  as  shown  in 
Fig.  291,  may  also  be  employed. 

B.  Lingual  Movement  of  Molars 

(1)  Fixed  Appliances. — This  is  exactly  as 
described  in  paragraph  11,  Chapter  VII.     Inter- 
maxillary force  may  be  used  as  an  auxiliary,  : 
in  the  reverse  way  just  described  for  buccal 
movement  under  (1)  (c). 

(2)  Removable  Appliances. — This  has 
already  been  described  in  paragraph  12,  Chapter 
VII. 

C.  Medial  Movement  of  Molars  j 

(1)  Fixed  Appliances. — This  opportunity 
will  be  taken  to  jioint  out  that  when  a  nut  is 
used  on  a  bow  it  always  engages  the  medial 
end  of  a  buccal  tube.  It  is  never  intended  to 
be  put  on  the  bow  after  the  latter  has  passed 
through  the  tube  ;  this  would  always  be  difficult 
— at  times  impossible.  There  are  simpler 
methods  of  obtaining  the  same  result  as  would  i 
be  achieved  by  that  means. 

Molars  are  moved  medially  by  means  of  force 

from  an  elastic  band  caught  on  the  distal  end 

of  the  buccal  tube  behind,  and  in  front  to  a  hook 

opposite  the  canine  in  either  jaw,  according  to 

the    needs    of   the    case.     If   the    elastic    band 

operates  on  one  jaw  only  the  operator  must  be  j 

prepared  for  the  incisors  to  move  distally  or 

lingually,  as  it  is  unlikely  that  they  can  give 

the  necessary  anchorage ;    the  buccal  tube  and 

bow  permit  of  translatirnal  movement  only,  if 

the  bow  is  held  in  a  fixed  ]x«ition  on  the  incisors. 

If  the  clamp-band  is  on  a  premolar,  the  molar 

may   also    be    banded,   and   carry   buccal   and 

1  igual  spurs,  with  rubber  bands  from  each  of 

e  to  some  anterior  point  on  either  the  bow 

'^anded  tooth.     Tilting  movement  is  pos- 

w,   and   less  force  will   be  required  to 

molar.  i 

"  Distal    Movement    of     Molars —  1 

^es  ",  p.  205.  I 

-I     Appliances. — A     soldered 


band,  having  two  spurs  both  directed  di.stally, 
one  on  the  buccal  aspect  and  the  other  on  the 
lingual,  is  cemented  to  the  tooth  to  be  moved. 
A  vulcanite  plate  is  made  with  buccal  and 
lingual  attachments,  each  of  which  is  to  hold 
a  rubber  band.  The  attachment  on  the  lingual 
surface  of  the  plate  is  fixed  as  far  forward  as 
possible  and  as  nearly  directly  in  front  of  the 
molar  as  can  be  arranged.  The  buccal  attach- 
ment is  a  platinized  gold  wire,  vulcanized  to 
the  plate  on  its  lingual  surface,  passing  thence 
to  the  buccal  aspect  of  the  teeth  between  the 
lateral  and  canine  or  canine  and  first  premolar, 
bent  up  towards  the  gingival  margin,  and 
terminating  in  a  hook,  which  will  support  a 
rubber  band  stretched  from  the  buccal  spur 
on  the  molar  band. 

A  rubber  band  is  similarly  attached  on  the 
lingual  surface  to  the  corresponding  spurs.  The 
plate  must  be  firmly  held  by  clasps,  one  on  the 
side  of  the  moving  tooth,  and  two  on  the  other 
side.  A  buccal  wire  on  the  incisors  would 
increase  the  resistance  and  stability  of  the 
plate. 

D.  Distal 

(1)  Fixed  Appliances.  (Exactly  as  in  para- 
giaph  23,  Chapter  VII.) — Another  methcd  is  to 
use  inter-maxillary  force  applied  direct  to  the 
tooth  to  move  it  distally.  The  anchorage,  simple 
or  reciprocal  as  may  be  desired,  is  obtained  from 
the  opposite  ja\\-,  the  corresponding  tooth  being 
employed  when  a  lower  molar  has  to  be  moved, 
and  one  more  distal,  if  possible,  when  the  upper 
molar  has  to  be  moved.  The  spurs  to  which 
the  rubber  bands  are  attached  should  be  well 
forward  on  the  distally  moving  tooth  and  far 
back  on  the  medially  moving  tooth,  so  as  to 
make  the  rubber  bands  as  efficient  as  possible, 
though  this  position  of  the  spurs  tends  to  tilting 
of  the  molars. 

When  rcciiirocal  anchorage  is  used  the  oppos- 
ing molar  moves  mtdially.  This  principle  also 
applies  to  premolars. 

(2)  Removable  Appliances. — Exactly  as  in 
paragraj)h  24,  Chapter  VII. 

E.  Depression 

(1)  Fixed  Appliances. 

(2)  Removable  Appli.ances. 

This  is  a  movement  seldom  called  for,  but  it 
could  be  done  by  such  an  ap])aratus  as  shown 
in  Fig.  318  (Fixed),  and  Fig.  319  (Removable). 

F.  Elongation 

(1)  Fixed  Appliances. — This  is  best  done 
by  inter-maxillary  force  applied  to  the  tooth 
by  means  of  buccal  and  lingual  rubber  ligatures 
attached  to  sjjurs  on  a  plain  band.  The  resist- 
ance is  obtained  from  the  ojiposite  jaw  through 
the  medium  of  the  bow,  to  whicli  suitable  spurs 


206 


have  been  soldered  ;  the  bow  must  be  fixed  to  a 
number  of  teeth. 

(2)  Removable  Appliances. — A  plate  should 
be  made  with  buccal  and  lingual  wire  springs 
to  engage  hooks  on  the  corresponding  surfaces 
of  a  band  on  the  tooth  to  be  moved.  The  plate 
must  be  very  securely  held  in  place  by  crib- 
clasps,   and  the  pressure  on  the  tooth  be  as 


Fig.   318. — A  fixed  appliance  to  depress  a  molar, 
(a)  A  rigid  wire  bow  in  the  usual  position  in  the  incisor 

region,  but  shomi  at 
(6)  in  the  molar  region  to  have  been  bent  to  rest  high 

up  in  the  buccal  sulcus, 
(c)  Plain  or  clamp-bands;    to  those  on  the  premolars 

are  soldered 
((i)  spurs   to   support   the   bow;    there  is   also   a  spur 

on  the  molar  band  for  the  attachment  of 
(f)  book  for  attachment  of  rubber  band. 
(/)  A  rubber  band,  passing  over  the  rigid  bow  to  be 

attached  on  the  lower  jaw,  so  that  it  may  exert 

force  to  depress  the  upper  molar. 

moderate  as  is  consistent  with  obtaining  move- 
ment, because  the  direction  of  the  force  tends 
to  displace  the  plate. 

The  attachment  of  the  buccal  spring  must  be 
made  very  rigid,  not  only  to  the  plate,  but  also 
in  its  passage  to  assume  the  horizontal  position, 
which  it  takes  up  to  get  to  the  molar ;  the 
spring    should    pass    from    the  lingual  surface 


Fig.   319. — Cross-section  of  part  of  a  removable 
appliance  to  depress  an  upper  molar, 
(a)  Plain  band  to  which  is  soldered 
(6)  a  spur  directed  occlusally,  which  is  engaged  by 
(o)  a  coil  spring  fi-xed  in  a  vulcanite  plate  and  exerting 
force  in  the  direction  shown  by  the  arrows. 

between  canine  and  first  premolar  and  be  made 
of  platinized  gold  wire.  On  the  lingual  surface 
a  coil  spring  is  used,  attached  as  far  forward 
on  the  plate  as  possible. 

G.  Rotation 

(1)  Fixed  Appliances. — The  method  de- 
scribed by  E.  H.  Angle  is  to  give  the  extremity  of 
the  bow  a  bend,  so  as  to  a.ssume  a  position 
parallel  with  the  direction  that  the  buccal  sur- 
face of  the  molar  should  occupy  when  normally 
placed,    and    in   tlie    same    plane,   instead    of 


allowing  it  to  remain  parallel  with  the  direc- 
tion of  the  buccal  surface  of  the  tooth  in  its 
abnormal  position.  To  rotate  the  distal  corner 
of  the  tooth  outwards  is  comparatively  easy 
(see  Fig.  320),  for  this  takes  place  as  the  result 
of  expansion  force  applied  to  a  molar  through 
the  medium  of  a  buccal  tube  and  bow,  because 
the  distal  end  of  the  tube  ^^•ill  move  through 
a  larger  arc  of  a  concentric  circle  than  the 
medial  end.  This  movement  may  usually  be 
expected  \\  hen  using  a  bow  unless  care  is  taken 
to  prevent  it.  The  movement  may  be  increased 
by  Ijending  out^\■ards  the  extremity  of  the  bow. 

Slight  rotation  in  the  opposite  direction  may 
be  produced  by  giving  the  extremity  of  the 
bow  a  bend  inwards  just  in  front  of  the  nut 
(see  Fig.  321). 

Lowe  Young  (12,  p.  245)  describes  a  method  of 
rotating  a  molar  when  the  medio-buccal  corner 
has  to  be  moved  buccally  or  outwards. 


B 


Fig.  320. — The  heavy  lines  show  the  original  position 
of  the  anchor  tooth  and  buccal  tube,  on  the  clamp- 
band.  The  light  linos  show  the  position  of  the 
same  after  expansion  of  the  molar  if  the  ends  of 
the  bow  were  parallel  with  the  tubes  originally, 
and  no  further  adjustment  has  been  made.  (See 
also  Fig.  285.) 

The  clamp-band  is  fitted  with  the  screw 
directed  distally ;  the  buccal  tube  having  been 
removed,  a  shorter  tube  is  soldered  to  the  band 
at  the  medio-buccal  corner  and  parallel  with  the 
long  axis  of  the  tooth.  To  the  medial  end  of 
the  original  buccal  tube  a  short  length  of  wire, 
which  accurately  fits  the  new  buccal  tube  on 
the  band,  is  soldered  at  or  near  its  extremity 
and  at  right  angles  to  its  length,  so  that  when 
it  is  inserted  in  the  short  tube,  the  original 
buccal  tube  will  be  in  correct  position  to  accom- 
modate the  bow,  the  spring  of  which  exerts  an 
outward  movement  on  the  medio-buccal  corner 
of  the  tooth.  The  disto-lingual  corner  is  pulled 
inwards,  i.  e.  in  the  opposite  direction,  by  a 
rubber  band  stretched  from  a  spur  on  the 
lingual  surface  of  the  band,  distally,  to  a  spur 
on  the  bow,  if  there  is  no  second  deciduous 
molar  or  first  premolar.  This  spur  is  to  be 
so  situated  that  the  rubber  band  will  not  exert 
pressure  on  any  tooth  except  the  molar.  If 
there  is  no  space,  then  a  length  of  spring-wire 
is  soldered  to  the  disto-lingual  corner  of  the 
band  and  arranged  to  extend  forwards,  but 
directed  across  the  palate,  so  that  it  is  not  in 


207 


contact  witli  the  premolars;  it  is  then  pulled 
up  close  to  the  premolars  by  a  ligature,  \\  liieh 
passes  between  the  canine  and  lateral  and 
engages  the  bow  and  the  spring-wire. 

Tilting  of  Molars. — This  movement  has 
not  been  referred  to  in  the  classification  of 
tooth  movement,  though  molars  are  frequently 
seen  to  be  leaning  forward  as  the  result  of  loss 
of  the  medial  tooth.  The  movement  is  ef- 
fected by  a  method  similar  to  that  for  rotation 
described  first,  except  that  the  plane  in  which 
the  parallelism  of  tube  and  bow  extremity  varies 
is  the  vertical  one,  w  hereas  in  the  previous  case 
it  was  the  horizontal  one. 

In  the  present  instance  either  the  tube  or 
bow  extremity  may  assume  the  variable  position, 


a    I, 


nnr^ 


\ 

Fig.  321. — Rotation  of  the  distal  corner  of  a  molar 
inwards, 
(a)  Extremity  of  bow  as  bent  to  lie  parallel  with  the 

buccal  tube. 
(6)  Extremity  of  bow  as  bent  to  obtain  lingual  move- 
ment of  the  molar  without  any  rotation, 
(c)  Extremity  of  bow  as  bent  to  oljtain  rotation  inwards 
of  the  distal  corner  of  the  molar. 

SO  neither  will  interfere  with  the  comfort  of  the 
soft  tissues,  whereas  in  the  previous  case,  if 
the  direction  of  the  tube  varied  much  from  the 
general  direction  of  the  buccal  surface  of  the 
molar,  it  would  be  a  source  of  irritation  to  the 
soft  tissues  by  its  projecting  corner.  As  tilt- 
ing of  molars  is  usually  in  a  forward  direction, 
due  to  loss  of  the  tooth  m  front,  the  correc- 
tion of  that  position  will  be  described.  The 
simpler  way  is  as  follows  :  The  clamp-band 
is  adjusted  as  usual,  and  as  if  the  tooth  stood 
vertically  in  its  socket ;  the  tube  is  directed 
with  its  medial  end  downwards,  if  on  a  lower 
tooth  ;  the  bow  is  bent  as  usual,  but  instead 
of  this  extremity  being  made  parallel  \\ith 
the  tube,  it  is  left  in  the  position  it  would  oc- 
cupy if  the  tooth  were  normally  placed.  The 
bow  is  now  inserted  in  the  tubes,  and  its 
effect  on  the  malposed  molar  is  to  elevate  the 
medial  aspect  of  the  tooth  in  its  socket  and  to 


depress  the  other;  the  latter  being  the  nmch 
more  difficult  movement  to  produce,  the  former 
may  be  expected  to  happen.  There  will  also  be 
a  tendency  to  tilt  down  the  medial  end  of  the 
normal  molar,  which  for  the  reasons  just  given 
may  be  disregarded. 

Wlien  a  molar  on  each  side  has  to  be  tilted, 
the  bow  at  rest  will  be  over  the  gum  instead  of 
across  the  necks  of  the  incisor  teeth.  In  order 
that  it  may  exert  the  necessary  force  on  the 
molars,  it  must  be  pulled  up  to  the  teeth  and 
securely  ligatured  to  them ;  the  tendency  of 
this  is  to  depress  the  inci.sors  in  their  .sockets, 
but  as  depression  is  more  difficult  than  elevation, 
upward  movement  of  the  medial  aspect  of  the 
molar  may  be  expected,  rather  than  depression 
of  its  distal  end,  and  of  the  incisors. 

If  the  direction  of  the  buccal  tubes  on  the 
clamp-bands  is  changed,  so  as  to  correspond  with 
the  usual  bow  alignment,  then  the  extremity 
(or  extremities)  of  the  bow  must  be  bent  just 
in  front  of  the  nuts,  so  as  to  secure  an  arrange- 
ment similar  in  effect  to  that  already  described. 

II— PREMOLARS 

(with  which  Deciduous  Molars  are  to  be  included) 

A.  Buccal  Movement 

(1)  Fixed  Appliances. — If  the  clamp-band 
is  on  this  tooth,  then  it  is  moved  buccally  by 
the  direct  action  of  the  spring  of  the  bow.  If 
the  clamp-band  is  on  a  posterior  tooth,  then 
the  premolar  is  moved  buccally  by  ligaturing  it 
to  the  bow  and  tightening  or  renewing  the 
ligature  as  may  be  necessary.  The  marked 
convexity  of  the  lingual  surface  of  premolars 
is  frequently  a  cause  of  the  ligature  sliding  far 
down  on  the  tooth  to^^■ards  the  root,  so  that  it 
may  be  quite  covered  by  the  gum ;  thus  an 
irritation  of  the  soft  tissues  is  set  up,  which  may 
render  the  parts  quite  sore.  To  prevent  this 
a  crib  is  soldered  to  the  ligature ;  this  crib 
consists  of  a  piece  of  ligature  wire  soldered  to 
the  ligature  itself  at  both  ends  and  in  such 
a  position  that  it  will  occupy  the  medio-distal 
sulcus  of  the  tooth  when  the  ligature  is  in  posit  ion. 
Silver  solder  may  be  used  for  soldering  in  this 
instance. 

The  same  disadvantage  applies  to  ligatures 
on  deciduous  molars.  Pullen  (10,  p.  595)  advo- 
cates another  form  of  crib  for  dealing  \\ith 
these ;  an  extra  piece  of  ligature  wire  is  soldered 
to  the  centre  of  the  ligature;  this  wire  passes 
from  the  centre  of  the  lingual  surface  of  the 
tooth  across  the  occlusal  surface,  and  is  included 
^\■ith  the  two  ends  of  the  ligature  as  it  is  tied 
(see  Fig.  :i22). 

Second  premolars  may  be  moved  buccally, 
when  the  threaded  wire  of  a  clamp-band  passes 
across  the  lingual  surface,  by  stretching  be- 
tween the  two  a  piece  of  separating  rubber ;    it 


208 


must  not  be  forgotten  that  the  rubber  exerts 
the  same  amount  of  force  to  move  the  clamped 
or  banded  tooth  lingually,  and  slightly  to 
rotate  it,  as  to  move  the  premolar  outwards. 
The  tendency  of  the  molar  to  move  lingually 
may  be  opposed  by  the  spring  of  the  bow. 

The  buccal  movement  of  any  tooth  may 
usually  be  made  more  rapid  by  placing  a  piece 
of  separating  rubber  on  the  lingual  surface  of 
the  tooth  and  including  both  rubber  and  tooth 
in  the  ligature. 

It  is  presumed  that  in  all  these  cases  the 
operator  has  arranged  the  bow  either  to  afford 
the  necessary  anchorage  or  to  move  other 
teeth  as  desired. 

(2)  Removable  Appliances. — To  move  a 
premolar  buccally  ^\ith  these  appliances,  a 
spring,  a  small  jack-screw,  rubber,  or  the  expan- 
sion of  wood,  may  be  used. 

The  use  of  springs  in  such  situations  has 
already  been  referred  to  (Chapter  VII,  para- 
graphs 4  and  8). 

Rubber  is  used  by  cutting  a  dovetailed  slot 
in  the  plate  edge,  which  should  be  thickened 


Fig.  322. — Crib  ligature  for  a  deciduous  molar.  The 
central  strand  of  wire  is  soldered  to  the  wire 
encircling  the  tooth  and  included  with  it  when 
the  ligature  is  tied.      (After  Pullen.) 

for  the  purpose,  opposite  the  tooth  to  be  moved  ; 
in  this  slot  a  piece  of  rubber  is  placed  ;  the  dove- 
tailing holds  the  rubber,  which  should  be  a  piece 
sufficiently  large  for  the  plate  to  need  forcing 
into  position,  when  the  effort  of  the  rubber 
to  resume  its  original  shape  moves  the  tooth 
outwards. 

In  using  wood  the  plate  is  again  given  a 
thickened  edge  opposite  the  tooth  to  be  moved. 
In  the  edge  a  cylindrical  hole  is  cut,  and  a  piece 
of  compressed  hickory  wood  is  forced  into  it 
from  the  surface  that  is  in  contact  with  the 
tooth ;  the  wood  should  project  just  so  far 
that  a  little  effort  is  necessary  to  press  the  plate 
into  position.  The  moisture  of  the  mouth 
causes  the  wood  to  swell,  and  so  the  tooth  is 
moved. 

B.  Lingual  Movement 

(1)  Fixed  Appliances. — («)  By  stretching 
separating  rubber  between  the  bow  and  buccal 
surface  of  the  tooth  to  be  moved — the  elasticity 
of  the  rubber  moves  the  tooth  inwards.  It 
usually  happens  that  if  one  premolar  has  to 
be  moved  lingually  there  are  other  teeth  to  be 
moved  buccally,  and  then  the  use  of  rubber 


contributes  to  reciprocal  tooth  movement   (see 
Fig.  323,  A). 

If  simple  anchorage  has  to  be  used,  the  resist- 
ance must  be  carefully  thought  out  before 
rubber  is  employed,  or  else  the  desired  result  may 
not  be  obtained. 

(b)  Inter-maxillary  force  may  also  be  used 
to  move  a  premolar  lingually  by  stretching 
a  rubber  band  from  the  buccal  surface  of  the 
tooth  to  the  lingual  surface  of  an  opposing 
tooth,  or  teeth,  according  to  the  amount  of 
resistance  required,  which  again  depends  on 
whether  simple  or  reciprocal  movement  is 
desired.  The  rubber  bands  are  attached  to 
the  teeth  through  the  medium  of  bands  carrying 
suitable  spurs. 

(c)  If  no  other  movement  is  desired,  a  rubber 
band  may  be  stretched  from  one  side  of  the 
mouth  to  the  other,  and  by  making  use  of 
simple  anchorage  one  tooth  is  moved  lingually 
by  means  of  the  resistance  of  three  or  four 
teeth  on  the  other  side ;  this  resistance  is 
obtained  by  banding  one  tooth  and  soldering 
a  buccal  wire  to  it  that  shall  be  in  contact 
with  two  or  three  of  the  approximal  teeth. 
The  rubber  bands  are  attached  to  spurs  on  the 
lingual  surfaces  of  the  soldered  bands.  The 
method  is  applicable  only  in  the  upper  jaw. 

{(l)  Bands  are  attached  to  two  teeth,  one  on 
either  side  of  the  tooth  (or  teeth)  to  be  moved, 
and  coiuiected  by  a  buccal  wire.  Separating 
rubber  is  stretched  between  the  teeth  and  the 
wire ;  if  the  resistance  is  insufficient  lingual 
wires  may  lie  added  to  the  bands  to  increase  the 
resistance  of  the  banded  teeth  by  adding  thereto 
the  resistance  of  the  approximal  teeth.  As 
the  premolar  moves  the  wire  should  be  bent  to 
remain  in  contact  with  it. 

If  the  resistance  of  the  canine  and  premolar  is 
insufficient  that  of  the  lateral  incisor  and  molar 
should  lie  added  by  means  of  lingual  wires. 

(e)  The  plan  described  in  (a)  may  be  re- 
versed. As  before  two  teeth  are  banded  and 
united  by  a  lingual  wire.  Three  modes  of 
arrangement  of  the  wires  are  shown  in  the 
cUagram  (see  Fig.  323,  B,  C,  and  D).  The  wire 
may  be  soldered  directly  to  the  bands,  or  may 
fit  in  tubes  soldered  to  the  bands. 

(/)  By  a  Siegfried  spring  on  the  lingual  sur- 
face of  the  tooth  to  be  moved  (see  p.  217,  and 
paragraph  III  a  (1)  c.) 

(2)  Removable  Appliances.  —  (a)  By 
stretching  rubber  between  a  buccal  wire  fixed 
!  to  a  plate — this  has  the  great  disadvantage 
of  difficult  renewal,  which  would  be  necessary 
every  time  the  plate  is  removed  from  the 
mouth. 

(b)  By  a  rubber  band  stretched  from  the 
tootli  to  the  palatal  surface  of  the  plate,  where 
it  is  attached  on  a  spur,  or  to  the  opposite 
corresponding  tooth,  the  plate  being  cut  away 


209 


lingually  to  the  tooth  to  be  moved.  The  rubber 
bands  are  attached  to  the  teeth  through  the 
medium  of  bands  carrying  spurs. 

(c)  By  a  spring  on  the  palatal  surface 
of  tiie  plate,  which  engages  a  hook  on 
the  lingual  surface  of  a  band  on  the 
tooth  to  be  moved. 


of  the  premolar.     The  spring  should  be  made  to 
engage  the  distal  surface  of  the  premolar  well ,  and 


(1) 


C.  Medial  Movement 
Fixed    Appliances. — (a)    Clamp- 


band  on  the  first  permanent  molar.  A 
ligature  engages  the  tooth,  and  a  spur 
is  placed  on  the  bow  anterior  to  the 
tooth.  The  nut  on  the  bow  must  closely 
engage  the  medial  end  of  the  buccal 
tube,  as  it  is  the  molar  that  offers  the 
resistance  whereby  the  premolar  is 
moved. 

(6)  Clamp-band  on  the  premolar  that 
is  being  moved  medially.  The  nut  on 
the  bow  is  turned  considerably  forward 
so  that  it  is  quite  away  from  the  buccal 
tube,  or  it  may  be  removed  entirely. 
A  hook  to  engage  a  rubber  band  is 
soldered  well  forward  on  the  lower  bow 
on  the  same  side.  This  rubber  band  is 
stretched  from  the  liook  on  the  lower 
bow  to  the  distal  end  of  the  buccal  tube 
of  the  tooth  to  be  moved ;  the  lower 
teeth,  through  their  bow,  afford  the 
resistance  necessary  for  moving  the 
premolar  forward. 

(c)  A  plain  band  with  spur  is  made 
for  the  premolar  that  is  to  be  moved 
medially ;  a  band  is  stretched  from  this 
spur  to  a  suitable  fixed  point  in  the 
loA\er  ja\\',  which  may  be  a  single  tooth, 
more  than  one  tooth,  or  the  bow  itself, 
according  to  the  resistance  required. 

(rf)  If  the  first  upper  premolar  has 
to  be  moved  forward,  and  there  is  a 
space  between  it  and  the  first  permanent 
molar,  which  is  to  be  occupied  by  the 
second  premolar  later,  a  tiny  jack-screw 
may  be  fitted  between  the  two  teeth  ;  the 
premolar  will  move,  ceteris  paribus,  as 
it  offers  the  less  resistance.  The  jack- 
screw  may  be  attached  to  a  plain  band 
on  the  premolar.  To  this  band  is  soldered 
a  piece  of  threaded  \\ire,  which  ^^ ill  just 
occupy  the  space  between  it  and  the 
molar.  A  nut  is  put  on  this  threaded 
wire,  and  left  just  short  enough  to 
enable  the  band  to  be  cemented  in 
position.  Then  the  nut  is  turned  against 
the  molar,  and  the  space  enlarged  in  this 
way.  Methods  (a)  and  (c)  may  be  used 
in  conjunction  with  this  one. 

(2)  Removable    Appliances. — -Coil- 
springs  on  a  vulcanite  plate  offer  the  most  suit- 
able means  of  bringing  about  medial  movement 


Fig.  323. — Lingual  movement  of  a  premolar  by  fixed  appliances. 

A.  Wire  bow  in  position ;  second  premolar  and  canine  requiring 
buccal  movement. 

(a)  Wire  bow. 

(b)  Ligatures   for   buccal   movement  of   canine  and  second 
premolar. 

(c)  Rubber  wedge  between  bow  and  first  premolar  to  bring 
about  lingual  movement  of  the  latter. 

Notice  that  the  clamp-band  {</)  has  had  to  be  applied  with  the 
clamping  wire  directed  distally,  as  the  position  of  the  second 
premolar  prevents  its  proper  adjustment. 

B.  Lingual  wire  (it)  attached  to  plain  bands  (e)  on  the  lateral  and 
molar;  the  wire  has  a  spur  (/)  to  be  engaged  by  the 
ligature  (6),  the  repeated  tightening  of  which  moves  the 
premolar.  The  anchorage  is  reinforced  simple,  and  is 
obtained  from  the  lateral,  canine,  second  premolar,  and 
molar,  tlu'ough  the  lingual  wire. 

C.  Appliance  similar  to  B,  but  ancliorage  is  from  the  canine 
and  second  premolar  only. 

D.  Appliance  similar  to  C,  but  the  lingual  wire  is  extended 
to  the  molar  and  lateral  to  increase  the  anchorage. 

to  effect  this,  it  may  be  necessary  to  separate 
the  teeth  so  that  it  can  go  well  between  them. 


210 


D.  Distal  Movement 

(1)  Fixed  Appliances. — (a)  Clamp-band  on 
the  7nolar. 

(i)  By  ligaturing  the  premolar  to  the  molar, 
the  nut  on  the  bow  accurately  engaging  the 
buccal  tube,  and  the  anterior  teeth  being  liga- 
tured to  the  bow.  This  is  not  an  entirely 
satisfactory  method. 

(ii)  By  inter-maxillary  force  applied  to  the 
premolar  through  the  medium  of  a  band  and 
spur. 

(iii)  By  a  spur  favourably  situated  on  the 
bow,  and  ligaturing  the  tooth  to  it  at  this 
point.  The  anterior  teeth  must  be  firmly 
ligatured  to  the  bow  as  they  offer  the  resistance 
necessary  for  the  distal  movement  of  the  pre- 
molar. This  method  is  applicable  only  to  the 
first  premolar. 

{b)  Clamp-band  on  the  Premolar  to  be  moved. 
The  bow  is  closely  fitted  to  the  anterior  teeth, 
which  are  ligatured  to  it ;  these  then  offer  the 
resistance  necessary  for  moving  the  premolar 
distally  when  the  nut  is  turned  against  the 
buccal  tube  of  the  clamp-band.  Inter-maxillary 
force  may  be  used  as  an  auxiliary  to  effect  this 
movement.  If  the  clamp-band  is  on  the  second 
premolar  when  the  first  has  to  be  moved,  direct 
inter-maxillary  force  is  the  best. 

E.  Depression 

This  movement  is  so  rarely  wanted  that  it 
need  not  receive  a  special  description.  The 
method  described  for  performing  the  reverse 
movement,  elongation,  will  suggest  methods 
that  may  be  used. 

F.  Elongation 

(1)  Fixed  Appliances. — The  direct  applica- 
tion of  inter-maxillary  force  to  the  tooth  to  be 
moved,  and  acting  from  tlie  opposite  jaw,  is  the 
best  method  to  adopt.  The  rubber  band  is 
attached  to  a  spur  on  a  soldered  band  cemented 
to  the  tooth  ;  in  the  opposite  jaw  it  is  attached 
to  a  .spur  soldered  to  the  bow  in  such  a  position 
that  the  force  \\i\\  elongate  the  tooth  and  not 
move  it  medially  or  di.stally  ;  this  sjKir  is  directed 
towards  the  sulcus  between  the  cheek  and 
alveolus.  It  is  essential  to  see  that  there  is 
ample  medio -distal  space  for  the  tooth  to  move 
into ;  in  other  words,  to  see  that  the  tooth  to 
be  moved  is  not  impacted. 

(2)  Removable  Appliances. — This  move- 
ment is  one  usually  required  for  several  teeth 
and  then  the  ordinary  bite  plate  is  used.  If, 
however,  only  one  has  to  be  elongated,  it  may 
be  assumed  that  the  others  are  in  correct 
occlusion,  and  that  force  must  be  applied  direct 
to  the  tooth  to  bring  it  into  position,  the 
operator  having  first  ascertained  that  sufficient 
space   exists   for   its   reception.     In   these   cir- 


cumstances the  tooth  in  the  ordinary  course  of 
events  should  erupt  into  jjosition  without  any 
stimulus.  If  force  is  needed,  fixed  appliances 
are  to  be  preferred,  but  if  removable  ones  must 
be  used,  then  a  fixed  point  has  to  be  secured 
on  the  tooth  by  means  of  a  cemented  band 
^^'ith  a  spur  or  spurs  on  the  buccal  or  lingual 
surface  or  both.  Springs  are  then  arranged  in 
the  vulcanite  to  exert  pressure  on  the  tooth 
in  the  direction  of  its  long  axis  from  the  root 
towards  the  crown.  The  coil-.spring  should  be 
directed  from  behind  forwards  and  made  to 
engage  the  spur  on  the  cemented  band ;  the 
spur  should  have  an  inclination  towards  the 
gum  margin  and  then  the  spring  serves  the 
additional  purpose  of  securing  the  plate  in 
position ;  as  usual  the  coil  should  be  made  to 
exert  pressure  as  it  opens.  The  attachment  of 
the  spring  acting  on  the  buccal  surface  of  the 
tooth  must  be  extremely  rigid ;  and  this  in- 
cludes the  portion  of  it  that  leaves  the  plate  and 
passes  across  the  contact  points  of  two  teeth  to 
reach  the  buccal  surface,  including  the  bend 
that  is  necessary  here  (see  p.  202).  In  the  case 
of  the  lower  jaw,  the  force  will  tend  to  drive  the 
plate  into  the  floor  of  the  mouth ;  this  should 
be  overcome  by  cleats  engaging  the  occlusal 
surface  of  the  molar.  They  may  also  be  em- 
ployed in  the  upper  jaw  if  the  force  used  is 
sufficient  to  injure  the  soft  tissues. 

G.  Rotation 

(1)  Fixed. — Rotation  is  performed  by  means 
of  a  cemented  band  with  soldered  spur  as 
described  for  incisors. 

(2)  Removable. — These  appliances  cannot 
be  adapted  for  rotating  premolars. 

m— CANINES 
A.  Buccal  Movement 

(1)  Fixed  Appliances. — (a)  By  ligaturing 
the  tooth  to  the  bow,  \\hicli  has  been  bent  so 
as  to  stand  a  sufficient  distance  from  the  tooth 
for  the  ligature  to  be  used  to  the  best  effect. 
A  piece  of  separating  rubl^er  between  the  lingual 
surface  of  the  tooth  and  the  ligature  will  assist 
the  movement. 

If  the  tooth  has  to  be  moved  a  considerable 
distance — and  this  should  be  considered  in' 
connection  with  the  extent  of  buccal  movement 
required  by  the  first  premolar — a  divided 
expansion  (wire)  bow  is  desirable,  as  consider- 
able \\  idening  of  the  front  of  the  dental  arch  can 
be  effected  by  this  means  ;  the  teeth  are  ligatured 
to  it  in  the  usual  way.  A  divided  bow  may 
also  be  used  on  the  lingual  surface  of  the 
teeth,  though  its  adjustment  is  more  difficult ; 
it  acts  directly  on  the  teeth. 

(b)  A  jack-screw  acting  directly  on  the  tooth 
to  be  moved  may  be  employed  when  no  other 


211 


movement  is  required ;  anchorage  is  obtained 
from  several  teeth  on  the  other  side  of  the  moutli. 

(c)  A  Siegfried  spring  can  often  be  used  with 
advantage  when  one  tooth  only  lias  to  be 
moved,  and  its  wings  should  be  sufficiently  long 
to  extend  to  one  or  two  approximal  teeth  on 
each  side  of  it,  thereby  securing  the  anchorage 
necessary  to  move  a  canine.  The  spring  is 
attached  to  the  tooth  through  the  medium  of 
a  band  cemented  to  it  (see  Figs.  324  and  329). 
To  the  band  is  soldered  a  vertical  spur  bent 
on  itself ;  the  spring  is  slipped  on  to  this 
spur,  which  \\ill  usually  be  found  to  be  all 
tliat  is  necessary  to  hold  the  spring  in  position. 
If  the  wings  are  not  in  contact  \\  ith  the  buccal 
surfaces  of  the  teeth  they  should  be  bent  so  that 
this  may  be  brought  about.  A  ligature  from  the 
wire  of  the  spring  to  the  tooth  may  be  used  to 
keep  the  \\ings  in  position  should  there  be  a 
tendency  for  them  to  be  displaced. 

(2)  Removable  Appliances. — (a)  A  screw 
operating  on  the  lingual  surface  of  the  tooth 
is  a  satisfactory  method.  It  may  be  set  di- 
rectly in  the  vulcanite,  which  should  have  been 
thickened ;  or  a  nut  may  be  vulcanized  in  the 
plate,  thus  offering  a  permanent  hold  for  a 
suitable  screw  (see  Fig.  21)1),  which  may  be 
turned  by  a  tiny  screw-driver,  or  have  a  small 
head  cut  on  it  and  turned  with  a  watch-key. 


Fig.  324. — Siegfried  spring,  with  long  arms  to  move 
the  canine  and  lateral  buccally  and  the  central 
and  premolars  lingually. 

(a)  Plain  band  with  lingual  spur. 

(/)  to  the  lateral. 

(fc)  Spur  on  (a)  to  support 

(c)  the  body  of  the  spring. 

(rf)  The  wings  of  the  spring  in  contact  with  the  central 
and  premolar. 

(e)  Ligatures  holding  the  wings  of  the  spring  in  posi- 
tion on  the  teeth. 

Arrows  show  direction  of  movement  of  the  teeth. 

A  plate  of  this  nature  must  be  securely  held  by 
clasps. 

(b)  A  spring  operating  on  the  lingual  surface 
of  the  tooth  as  described  for  premolars.  The 
sloping  surface  of  a  canine  offers  little  hold 
for  a  spring  of  this  nature,  so  a  band,  having 
a  spur  lingually,  \^hich  will  hold  the  spring  in 
position,  should  be  cemented  to  the  tooth.     It 


should  be  remembered  that  there  will  now  be 
a  tendency  for  the  tooth  to  be  elongated  in  its 
socket. 

(c)  Wedges  of  rubber  or  wood,  set  in  dove- 
tailed slots  in  the  vulcanite,  which  should 
be  i^urposely  thickened  behind  the  tooth. 

B.  Lingual  Movement 

This  movement  is  not  frequently  needed, 
unless  in  combination  with  labial  movement  of 
incisors. 

A 


Fig.  325. — Lingual   movement    of    canines   combined 
with  labial  movement  of  incisors. 

A.  (a)   Spring  wire  bow  held  to  the  central  and  lateral 

by  spurs  (c)  on  the  bands  (6). 

B.  (d)  Ligatures  replacing  the  hooks  (e). 
The  arrows  indicate  the  direction  of  force. 

(1)  Fixed  Appliances. — The  bow  should 
rest  in  contact  with  the  tooth ;  then  when  it 
is  ligatiu-ed  to  the  incisors  pressure  is  brought 
to  bear  on  the  buccal  surface  of  the  canine 
(see  Fig.  325,  B). 

In  order  that  the  pressure  may  be  constant, 
a  strip  of  rubber  may  be  jjuUed  between  the 
tooth  and  the  bow,  the  former  being  pressed 
inw  ards  and  the  latter  outwards  ;  this  increases 
the  effect  of  the  ligatures  on  the  incisors.  If  a 
lingual  bow  is  being  u.sed,  the  tooth  should  be 
ligatured  direct  to  this  when  it  will  be  pulled 
lingually. 

(2)  Removable  Appliances — (a)  A  band, 
having  a  lingual  spur  directed  cervically,  is 
cemented  to  the  tooth ;  in  the  palate  of  the 
vulcanite  plate  a  spur  is  set  to  oppose  that  on 
the  tooth.  The  plate  having  been  cut  away 
behind  the  tooth,  but  accurately  fitting  the 
lingual  surfaces  of  the  other  teeth,  a  rubber 
band  is  attached  to  the  two  spurs,  ^\■ith  the 
effect  that  it  pulls  the  canine  lingually.  Clasps 
sliould  be  used  to  hold  the  plate  in  position. 

(b)  A  Iniccal  wire  may  be  arranged  to  press 
on  the  buccal  surface  of  the  tooth  and  carry 
it  inwards,  but  oidy  slight  force  can  be  obtained 
in  this  way.     If  the  wire  is  extended  to  the 


212 


incisors  on  the  opposite  side — supposing  it 
necessary  to  carry  these  outwards — so  as  to 
engage  hooks  on  them,  and  is  bent  so  as  to  be 
in  contact  with  the  canine,  it  will  exert  pressure 
on  incisors  and  canine  in  opposite  directions 
(see  Fig.  325,  A).  A  buccal  wire  on  the  right 
side  should  move  the  left  incisors  forward,  and 
a  left  wire  the  right  teeth.  If  it  is  possible 
for  the  patient  to  stretch  rubber  between  the 
canine  tooth  and  the  wire,  the  movement  of  all 
the  teeth  will  be  accelerated. 

The  wire  should  lie  on  the  gingival  aspect  of 
the  spurs,  as  then  it  tends  to  hold  the  plate  in 
position,  and  may  also  be  used  to  elongate  the 
incisor  teeth  in  their  sockets  if  that  is  desired. 
The  wire  should  not  be  thicker  than  18  gauge, 
so  that  it  may  readily  conform  to  the  required 
shape,  and  the  canine  on  the  plaster  model 
should  be  cut  away  slightly  before  the  plate  is 
made,  so  that  the  wire  ^\■ill  come  into  forcible 
contact  with  this  tooth. 

C.  Medial  Movement 

(1)  Fixed  Appliances. — (a)  By  means  of  a 
ligature  from  the  tooth  to  the  bow,  to  which 
a  suitable  spur  is  attached  just  anterior  to  the 
medial  surface  of  the  canine — this  spur  must  be 
included  in  the  ligature. 

(b)  By  means  of  a  jack-screw  operating  from 
the  fust  molar — movement  of  the  molar  instead 
of  the  canine  must  be  watched  for. 

A  clamj)-band  with  buccal  tube  is  cemented  to 
the  molar;  a  plain  band  with  horizontal  tube, 
but  at  right  angles  to  that  on  the  molar,  is 
cemented  to  the  canine ;  a  rod  is  fitted  to  pass 
into  the  two  tubes,  the  end  entering  the  molar 
tube  being  threaded  and  carrying  a  nut.  The 
nut  engages  the  medial  end  of  the  tube,  against 
which  it  is  turned  to  move  the  canine  forward. 
This  appliance  permits  of  translational  move- 
ment only  of  the  molar,  up  to  a  point,  and  of 
inclinational  movement  of  the  canine,  which  is 
the  desirable  arrangement ;  if  there  is  any 
tendency  for  the  anchorage  to  give  way,  inter- 
maxillary force  must  be  applied  at  once. 
Force  should  not  be  exerted  too  rapidly.  This 
appliance  is  in  principle  identical  with  the  bow 
as  regards  movement  of  the  canine,  for  tilting 
of  the  molar  may  be  prevented  by  taking  steps 
to  hold  the  bow  in  a  constant  position  in  the 
front  of  the  mouth  by  ligaturing  the  incisors 
to  it,  or  applying  bands  to  these  teeth,  notching 
the  seams,  and  allowing  the  bow  to  rest  in  these. 
The  latter  is  preferable,  as  the  bow  will  move 
towards  the  incisal  edges  of  the  teeth  and  liga- 
tures alone  do  not  resist  this  tendency ;  it 
would  be  further  necessary  to  band  the  teeth 
and  to  solder  lingual  spurs,  directed  gingivally, 
to  the  bands. 

(2)  Removable  Appliances. — (a)  With  a 
coil  spring  fixed  in  a  vulcanite  plate  and  oper- 


ating on  the  distal  surface  of  the  canine.  This 
can  only  be  used  in  the  upper  jaw.  Li  the 
lower  jaw  the  movement  is  more  difficult  and 
could  only  be  produced  if  there  is  a  space 
behind  the  cairine.  If  the  space  is  large — as 
when  two  premolars  are  unerupted — a  Coffin 
sirring  may  be  used.  This  must  be  a  small 
spring  fitted  in  the  space,  and  when  the  plate 
has  been  vulcanized  it  is  sjiUt  about  opposite 
the  centre  of  the  spring,  which  may  now  be 
gradually  opened  as  the  tooth  (or  teeth)  moves  ; 
both  sides  may  be  treated  at  the  same  time  (see 
Fig.  301).  Due  consideration  must  be  given  to 
anchorage.  If  the  space  is  too  small  for  this,  a 
screw  rumiing  in  a  nut  vulcanized  in  the  plate 
may  be  employed.  The  screw  is  readily  replaced 
by  a  new  one  when  necessary. 

{b)  By  fixing  a  plain  band  to  the  canine,  with 
a  buccal  spur  directly  distally,  the  elasticity  of 
rubber  may  be  used  to  pull  the  tooth  medially. 
One  end  of  the  rubber  band  is  attached  to  the 
spur  just  mentioned,  and  the  other  to  a  hook 
at  the  end  of  a  buccal  wire  attached  to  the 
plate  and  coming  sufficiently  far  forward  to 
obviate  the  use  of  a  long  rubljer  band.  Wliere 
this  touches  the  incisors  the  plate  should  fit 
close  behind  them  to  prevent  these  being  forced 
lingually,  unless  this  movement  is  desired. 

D.  Distal 

(1)  Fixed. — (a)  When  the  bow  is  used,  this 
movement  is  effected  by  means  of  a  ligature 
attaching  the  tooth  to  the  bow,  but  including 
also  a  spur  on  the  bow,  which  is  situated  a 
little  behind  the  distal  surface  of  the  tooth  (see 
Fig.  292).  The  anchorage  for  this  movement  is 
not  obtained  from  the  molar,  but  from  the  in- 
cisors, so  they  must  be  closelyobserved  to  see  that 
they  do  not  give  way  (unless  buccal  movement 
of  them  is  desired)  before  the  canines  move; 
if  they  do,  inter-maxillary  force  should  be  used 
at  once  to  check  this  movement. 

(6)  Wlien  upper  and  lower  bows  are  in  position, 
a  band,  carrying  a  long  spur  directed  towards 
the  incisal  edge  and  bent  to  form  a  hook  facing 
the  medial  edge  of  the  tooth,  may  be  cemented 
to  the  tooth.  A  rubber  band  is  then  attached 
to  this  hook  and  to  the  distal  end  of  the  buccal 
tube  on  the  same  side,  but  in  the  opposite  jaw. 
A  powerful  force  is  applied  direct  to  the 
canine ;  the  opposite  bow  must  be  arranged  so 
that  there  is  no  possibility  of  movement  of  the 
molar,  unless  this  is  specially  desired.  If  the 
rubber  band  is  attached  at  the  back  of  the 
buccal  tube  of  the  same  jaw,  the  resistance  of 
the  molar  and  incisors  is  available  for  moving 
the  canine,  as  long  as  the  incisors  are  ligatured 
to  the  bow,  and  the  nut  engages  the  medial  end 
of  the  buccal  tube.  This  resistance  is  not  always 
sufficient.  The  tendency  is  for  the  rubber  band 
to  pull  forward  the  upper  bow  and  teeth  attached 


213 


to  it ;  if  it  is  necessary  to  increase  the  resistance 
to  this  movement,  a  rubber  band  may  be  used 
betw  een  a  hook  opposite  the  canine  on  the  bow 
and  the  distal  end  of  the  buccal  tube  in  the 
opposite  jaw  on  the  same  side. 

(c)  By  means  of  a  jack-screw  exactly  as 
described  on  p.  212  for  medial  movement  of 
canines,  except  that  the  nut  must  engage  the 
distal  end  of  the  molar  tube  and  be  turned  to 
bring  the  teeth  closer  together.  If  there  is  a 
bow  attached  to  the  teeth  of  the  opposite  jaw, 
inter-maxillary  force  may  be  used  as  an 
auxiliary. 

On  account  of  the  comparatively  great  resist- 
ance a  canine  offers,  it  would  be  unwise  to  use 
inter-maxillary  force  derived  from  one  preznolar 
in  the  opposite  jaw. 

(2)  Removable  Appliances. — Distal  move- 
ment of  canines  is  more  easily  performed  by 
removable  appliances  than  the  opposite  move- 
ment. The  simplest  method  is  the  U -spring, 
one  or  more  loops  being  used  as  may  be  neces- 
sary, passing  from  the  lingual  surface  of  the 
plate  between  first  molar  and  second  premolar, 
or  between  the  first  and  second  molars,  to  the 
medial  surface  of  the  canine,  the  U -loops  inter- 
vening. The  wire  should  be  bent  at  right 
angles  at  its  medial  extremity  to  engage  the 
canine  accurately  at  the  gum  margin.  Piano 
wire  or  platinized  gold  may  be  used.  The 
U -loops  may  be  replaced  by  a  rubber  baud. 
In  that  case  the  attachment  to  the  plate  is 
bent  to  form  a  suitable  hook,  as  soon  as  it 
reaches  the  buccal  surfaces  of  the  teeth ;  the 
canine  must  be  banded,  the  band  having  a 
buccal  spur,  directed  medially,  which  forms  the 
other  attachment  for  the  rubber  band. 

E.  Depression 

This  is  a  movement  that  is  probablj'  never 
required. 

F.  Elongation 

(1)  Fixed  Appliances.  —  Inter-maxillary 
force  is  the  only  method  that  calls  for  con- 
sideration. A  plain  band  with  spur  on  the 
buccal  or  lingual  surface,  directed  gingivally, 
is  cemented  to  the  tooth,  and  a  rubber  band 
is  attached  to  it  and  to  a  hook  on  the  lower 
bow,  A\hich  must  be  arranged  to  give  the 
necessary  anchorage  by  being  ligatured  to  a 
sufficient  number  of  teeth. 

\Vlien  the  tooth  is  not  sufficiently  erupted  for 
a  band  to  be  applied,  a  small  pit  must  be  drilled 
in  the  lingual  surface  of  the  tooth  and  a  short 
length  of  wire,  directed  gingivally,  cemented  in 
it  to  act  as  a  spur — the  rubber  band  is  attached 
to  this  instead  of  to  the  spur  on  the  band. 

(2)  Removable  Appliances  for  this  move- 
ment are  not  to  be  regarded  as  efficient — the 
method  described  for  premolars  might  be  used 
if  the  attempt  is  to  be  made.  i 


G.  Rotation 

(1)  Fixed  Appllances.— This  movement  is 
performed  as  described  for  incisors,  p.  215. 

(2)  Removable  Appliances.— These  appli- 
ances cannot  be  adapted  for  rotating  canines. 

IV— INCISORS 
A.  Labial  Movement 

(1)  Fixed  Appliances.— There  is  little  to  be 
added  to  what  has  been  said  on  p.  195,  where 

j  the  movement  of  the  incisors  collectively  has 
I  been  discussed.  If  the  movement  of  one  tooth 
i  in  particular  has  to  be  accelerated,  a  piece  of 
rubber  may  be  placed  on  the  lingual  surface  of 
the  tooth  and  included  in  the  wire  ligature ; 
when  tliis  has  been  tied,  the  ends  of  the  rubber 
are  cut  off  short,  so  that  the  one  end  shall  not 
impinge  on  the  soft  tissues,  and  the  other  not 
be  a  source  of  irritation  to  the  tongue.  Wire 
ligatures  are  to  be  preferred  unless  some  force 
in  the  ligature  itself  is  desirable,  as  when  one 
tooth  has  to  be  moved  considerably  further 
than  another ;   in  that  case  silk  should  be  used. 

(2)  Re.movable  Appliances. — (a)  Force  ap- 
plied on  the  lingual  surface. — There  is  little  to 
add  to  what   has  been  said   in  paragraph   39, 

I  Chapter  VII,  under  this  heading,  except  that 

the  methods  described  there  are  apphcable  to  one 

or  two   teeth  rather  than  to  all  four  incisors. 

I  When  wedges  of  wood  or  rubber  are  used,  these 

i  are  made  just  a  little  tliicker  than  will  permit 

of  the  plate  going  into  position  immediately. 

I  The  teeth  then  move  a  little,  which  allows  the 

I  plate  to  go    "home",  and  following  this  the 

wedge  exjjands,  and  so  the  tooth  movement  is 

continued.     Another    method    is     to     drill    a 

circular    hole    in    the    \'ulcanite    immediately 

behind  the  tooth  to  be  moved,  and  to  cut  a, 

peg  of   wood  to  fit  tightly  into  this,  and  left 

long  enough  to  exert  pressure  on  the  tooth. 

(&)  Force  applied  on  the  labial  surface  of  the 
teeth. 

A  band  must  be  fixed  to  the  tooth,  and  have  a 
spur  soldered  to  it,  which  is  bent  in  a  curve  so 
that  it  may  be  engaged  by  a  platinized  gold  wire 
spring  (see  Fig.  325,  A).  This  spring  is  carried 
from  the  lingual  aspect  of  the  plate  in  the 
premolar  region,  and  brought  round  the  labial 
surface  of  the  teeth  to  engage  the  spur  already 
referred  to  on  its  gingival  aspect.  By  bcnchng 
this  wire  outwards  pressure  is  exerted  on  the 
tooth  in  a  labial  direction.  When  the  lower 
incisors  occlude  with  the  cmgula  of  the  upper 
incisors,  it  may  not  be  practicable  to  use  any 
of  the  methods  previously  described,  but  this 
one  could  be  adopted  with  success.  If  the  wire 
spring  is  to  move  the  teeth  on  the  right  side 
it  should  be  attached  on  the  left  side  of  the 
plate  and  pass  across  the  incisors  on  that  side 


214 


to  those  on  the  right ;  the  greater  length  of  wire 
gives  greater  spring. 

B.  Lingual  Movement 

(1)  Fixed  Appliances. — When  only  one 
tooth  has  to  be  moved  lingual'y,  this  is  done 
by  bending  the  bo«'  to  fit  closely  to  the  incisors 
and  canines  just  below  the  gum  margin.  All 
the  teeth  except  the  one  to  be  moved  are  tied 
to  the  bow  with  wire  ligatures.  These  offer  the 
necessary  resistance  for  moving  the  one  tooth 
lingually,  which  is  done  by  stretching  a  piece 
of  separating  rubber  and  draA\ing  it  between 
the  tooth  and  the  bow,  and  cutting  off  the 
surplus  ends  when  it  is  held  in  place  (as  for 
the  premolar  in  Fig.  323,  A).  As  the  tooth 
moves  the  rubber  should  be  replaced  by  a  thicker 
piece,  and  if  the  movement  is  considerable  the 
bow  should  be  rebent  to  conform  to  the  new 
positions  of  the  teeth. 

A  bow  as  usually  applied  is  not  essential,  if 
only  the  one  tooth  has  to  be  moved ;  all  that 
would  be  necessary  is  two  plain  bands  on  the 
first  premolars,  with  short  buccal  tubes,  into 
which  a  plain  wire  is  fitted,  so  as  to  pass  from 
one  tube  to  the  other  and  be  in  contact  with 
all  the  teeth. 

(2)  Removable  Appliances. — ^The  appliances 
described  in  paragraph  41,  Chapter  VII,  for 
the  movement  of  several  incisors  lingually  are 
equally  applicable  to  moving  one  tooth  in  that 
direction.  Any  modifications  required  are  suffi- 
ciently obvious  not  to  need  special  descrip- 
tion. It  is  necessary  to  make  certain  that  the 
space  for  the  tooth  to  move  into  is  sufficient 
for  its  reception. 

C.  and  D.  Medial  and  Distal  Movement 
Fixed  and  Removable  Appliances. — What 
has  been  said  in  paragraphs  42  and  43,  Chapter 
VII,  in  regard  to  movement  of  the  four  incisors 
applies  equally  to  them  individually,  the  ap- 
pliances being  arranged  so  as  to  operate  only  on 
the  one  misplaced  tooth. 

E.  Depression 

(1)  Fixed  Appliances. — When  a  single  inci- 
sor is  elongated  in  its  socket  a  radiograph  should 
be  obtained,  so  that  the  root  and  bony  surround- 
ings of  the  tooth  may  be  compared  with  its 
neighbours.  It  would  be  unwise  to  depress  a 
tooth  whose  total  length  was  greater  than  its 
fellows.  In  any  case  it  would  appear  that  the 
extent  to  which  it  is  advisable  to  depress  a 
tooth  is  very  limited,  as  it  necessitates  imme- 
diate absorption  of  bone  or  tooth  or  both, 
whereas  it  is  highly  probable  that  all  other 
tooth  movements  are  the  combined  result  of 
absorption  and  bending  of  bone. 

A  single  tooth  may  be  depressed  in  its  socket 
by  soldering  to  the  bow  an  auxiliary  wire,  which 


will  pass  across  the  soft  tissues  beyond  the  necks 
of  the  teeth.  It  should  be  soldered  to  the  bow 
on  either  side  of  the  tooth  to  be  moved,  and 
immediately  above  the  tooth  should  have  a 
spur,  directed  towards  the  sulcus,  soldered 
to  it.  The  tooth  itself  should  have  a  band 
cemented  to  it  as  near  the  incisal  edge  as 
possible,  with  a  labial  spur  directed  towards 
the  incisal  edge  of  the  tooth  (see  Fig.  326). 

Inter-maxillary  force  may  be  combined  with 
the  method  described,  the  rubber  band  passing 
from  the  spur  on  the  band  on  the  elongated 
tooth  over  the  auxiliary  wire  to  a  spur  on  the 
lower  bow. 

(2)  Removable  Appliances. — A  band  is 
fixed  to  the  tooth  as  before  but  need  not  be  so 
near  the  incisal  edge ;  a  labial  spur  is  arranged 


Fig.   320. — Depression  of  a  single  incisor. 
A.   Buccal  view.     B.   Cross-section. 

(a)  Wire  bow,  with 

(6)  an  accessory  wire  soldered  to  it  as  shown. 

(c)  Plain  band  with 

(<i)  spur  to  be  engaged  by 

(/)  a  rubber  band,  attached  also  to 

(e)  a  spur  on  (b). 
The  pull  of  the  rubber  band  depresses  the  incisor. 
The  bow  (a)  must  be  firmly  tied  to  as  many  teeth  as 
possible. 

on  it  by  suitably  cutting  the  seam.  A  buccal 
wire  on  a  vulcanite  plate  is  arranged  to  engage 
this  spur  and  to  exert  pressure  on  it  towards 
the  root  of  the  tooth.  Clasps  will  be  necessary 
to  maintain  the  plate  in  position. 

F.  Elongation 

(1)  Fixed  Appliances. — {a)  A  ligature  is 
securely  fixed  to  the  neck  of  the  tooth  and  the 
ends  are  then  twisted  round  the  bow ;  if  the 
latter  is  nearer  the  incisal  edges  of  the  ap- 
proximal  teeth  than  the  tooth  to  be  elongated, 
this  will  suffice  to  perform  the  movement. 

(b)  The  tooth  to  be  elongated  is  banded  ;  on  the 
labial  surface  of  the  band  a  spur  is  soldered  ;  a 
rubber  band  is  stretched  from  this  spur  to  one 
suitably  placed  on  the  lower  bow,  the  effect 
being  to  elongate  the  tooth. 

(c)  Should  methods  (a)  and  (b)  not  be  ap- 
plicable, then  the  method  just  described  under 
"  E.  Depression — Fixed  Appliances  "  may  be 
used  ;  but  the  auxiliary  wire  over  the  soft  tissues 
must  be  replaced  by  one  passing  across  the  in- 
cisal edges  of  the  teeth.     The  ligature  described 


215 


in  (fl)  may  be  attached  to  the  auxihary 
wire,  or  the  tooth  may  have  a  band  cemented 
to  it.  To  the  band  a  spur,  directed  gingivally, 
is  soldered  as  near  the  neck  of  the  tooth  as 
possible.  A  rubber  band  is  attached  to  the 
spur  on  the  band  and  to  one  on  the  auxiliary 
wire ;  this  has  the  effect  of  elongating  the 
tooth. 

(2)  Removable  Appliances. — A  buccal  wire 
is  made  to  engage  a  labial  spur  on  a  band 
cemented  to  the  tooth  to  be  moved ;  the  wire 
is  bent  to  exert  pressure  on  the  spur  in  the 
direction  of  the  incisal  edge  of  the  tooth,  which 
is  thus  elongated.  Li  place  of  the  buccal  wire 
passing  from  one  premolar  region  to  the  other, 
a  separate  wire  may  be  brought  from  each  side 
and  both  arranged  so  as  to  exert  pressure  on 
the  tooth. 

G.  Rotation 

(1)  Fixed  Appliances. — (a)  The  most  satis- 
factory method  is  to  band  the  tooth,  and  to 
solder  on  the  lingual  asjiect  of  the  instanding 
comer  of  the  band  a  spur  directed  towards  the 
opposite  corner.  This  spur  must  be  as  near  the 
cervical  edge  of  the  tooth  as  possible  (see  Fig. 
337(rf)  and  (e))  ;  it  affords  a  means  of  attaching 
a  ligature  directly  to  the  corner  of  the  tooth 
and  thus  pulling  that  corner  outwards  when 
tlie  ligature  is  secured  to  the  bo\\'.  Even  now 
the  tooth  will  to  some  extent  move  directly 
forwards  till  the  outstanding  corner  is  in  con- 
tact with  the  bow,  which  then  resists  this 
movement,  on  account  of  the  much  greater 
resistance  offered  to  rotatory  than  to  labial 
movement.  If  it  is  desired  to  hasten  the  rota- 
tion of  the  tooth,  a  piece  of  separating  rubber 
sliould  be  stretched  between  the  outstanding 
corner  and  the  bow  (the  ends  being  cut  off 
short).  This  has  the  effect  of  pushing  in  the 
outstanding  corner,  and  so  considerably  in- 
creasing the  movement  of  rotation. 

(6)  A  ligature  and  one  or  two  rubber  wedges 
(as  shown  in  Fig.  327)  may  be  used  in  cases  of 
slight  rotation. 

(c)  If  a  bow  is  not  being  used,  a  tooth  may 
be  rotated  by  cementing  to  it  a  band  with  two 
spurs  soldered  to  it ;  one  is  attached  to  each 
surface,  one  to  reach  to  the  approximal  tooth 
medially,  and  the  other  to  the  approximal  tooth 
distally.  If  the  medial  comer  of  the  tooth  is 
instanding,  a  spur  is  soldered  to  that  comer 
of  the  band  on  the  labial  surface  ;  if  the  rotated 
tooth  is  much  out  of  alignment,  the  spur  will 
need  to  have  a  bend  in  it,  so  that  it  may  be  in 


contact  with  the  labial  surface  of  its  fellow. 
The  opposite  comer  is  dealt  with  in  the  same 
mamier,  except  that  the  spur  is  soldered  to  the 
lingual  surface  of  the  band  and  made  to  come 
in  contact  with  the  lingual  surface  of  its  fellow 
distally.  If  both  comers  of  the  tooth  have  to 
be  moved,  then  rubber  is  stretched  between 
both  spurs  and  the  corresponding  teeth,  larger 
pieces  of  rubber  being  used  as  the  space  between 
the  spurs  and  teeth  increases.  If  only  one 
comer  has  to  be  moved,  then  rubber  is  used  to 
operate  on  that  one  comer  only,  the  spur  on  the 
opposite  comer  serving  as  a  means  whereby 
resistance  is  obtained  to  prevent  a  direct  labial 


Fig.  327. — Ligature  for  rotation  of  a  tooth  in  slight 
torso-occlusion. 

(a)  The  wire  bow. 

(b)  Ligatures. 

(c)  Ligature,   which   terminates  at   its   starting  point, 

having    passed    once    round    the    bow    and    twice 

round  the  tooth  as  shown. 
((!}  Knot  of  ligatiu'e  formed  by  a  three-quarter  tiu-n 

only,    and    with   the   ends   bent   under   and   over 

the  bow  out  of  the  way. 
(e)  Twisted   knot   leaving  one  strand,   wliich  is  more 

rigid  and  so  less  easily  displaced. 
(/)  Rubber   wedges   to   increase   the   rotatory   motion 

of  the  tooth. 

or  lingual  movement  of  the  tooth.  If  the 
rotatory  movement  required  is  considerable,  the 
band  should  be  removed  from  time  to  time  so 
that  the  spurs  may  be  re-soldered  to  lie  in 
contact  with  the  approximal  teeth  again,  when 
small  sections  of  rubber  may  once  more  be  used 
and  gradually  increased  in  size  as  the  tooth 
moves.  Wlien  it  is  in  its  correct  position  the 
band  is  again  removed,  and  the  spurs  are 
re-soldered  to  be  in  contact  with  the  adjoining 
teeth,  thus  converting  the  appliance  into  a  very 
eflScient  retaining  apparatus.  The  spurs  may 
be  lengthened  to  reach  across  two  approximal 
teeth  on  each  side,  if  one  on  each  side  does 
not  offer  sufficient  resistance  to  rotate  the  tooth 
without  its  fellows  moving. 

(2)  Removable  Appliances. — As  a  general 
rule  these  are  not  efficient  for  rotating  teeth. 


CHAPTER  IX 

ABNORMALITIES   OF   POSITION— TREATMENT   (continued) 


THE  HEAD-GEAR  AND  TRACTION  BAR 

This  is  an  adjunct  to  the  expansion  bow, 
especially  valuable  when  the  upper  incisors 
have  to  be  moved  lingually  or  the  upper  canines 
or  the  upper  molars  have  to  be  moved  distally. 

The  head-gear  consists  of  a  cross-bar  and 
skull-cap.    (See  Fig.  328.)     The  former  (see  Fig. 


A 

— V- 


C^33I 


IT 


Fig.  .328.— The  Head-gear. 

A.  The  ami  attached  to  the  apphance  in  the  mouth. 

B.  The  net  skull-cap  attached  to  a  steel  frame. 

C.  Elastic  bands  uniting  A  and  B. 
(a)  Attacliment  on  A,  which  rests  on  a  knob  on  the  bow  in 

the  mouth. 
(6)  The  ends  of  A,  curved  for  the  attachment  of  the  rubber 

bands, 
(a'),   (a)  in  cross-section,  showing  the  concavity  in  which  the 

knob  on  the  bow  rests.      (After  Angle.) 


328,  A)  is  attached  to  the  wire  bow,  is  outside 
the  mouth,  and  is  long  enough  to  extend  be- 
yond the  comers  of  the  mouth  when  placed 
horizontally  in  front  of  it.  The  attachment  of 
cross-bar  to  wire  bow  is  a  loose  one ;  in  the 
centre  of  the  former  there  is  a  small  socket  (see 
Fig.  328  a  and  a'),  to  engage  a  corresponding 
ball,  which  is  soldered  to  the  front  of  the  bow 
between   the    two    central    incisors.      At  each 

210 


extremity  the  cross-bar  is  bent  into  a  hook, 
the  concavity    being    directed  forwards.     The 
connection  with  the  occiput  is  by  means  of  the 
skull-cap  (see  Fig.  328,  B),  which  is  a    thread 
net  attached  to  a  frame  shaped  to  fit  the  back 
of  the  head  and  the  neck.     This  is  the  anchor 
portion  of   the  appliance,  and  it  is  comiected 
to  the  other  portion   first   described,  which  is 
the  medium  whereby  force  is  transmitted 
to  the  teeth,  by  means  of  heavy  elastic 
bands  which  exert  the  force.     The  direc- 
tion of  the  force  may  be  backwards  and 
upwards,    or   more    directly    backwards 
according  to  the  position  of  the  elastic 
bands  on  the  frame  of  the  skull-cap. 

Ten  years  or  so  ago  the  head -gear  was 
employed  much  more  than  it  is  to  day, 
but  with  the  use  of  inter-maxillary  force 
it  has  almost  entirely  fallen  into  disuse, 
though  there  are  occasions  when  it  may 
be  called  into  requisition  \\  ith  advantage. 
Probably  its  most  useful  ajoplication  is 
^^hen  two  upper  premolars  have  been 
removed  in  order  that  the  canines  and 
incisors  may  be  brought  back,  and  so 
tlieir  relation  Avith  the  rest  of  the  face 
changed.  The  incisors  will  move  lin- 
gually by  the  bow  acting  directly  on  to 
them  ;  the  bow  is  held  in  correct  relation 
w  ith  the  incisors  by  having  it  rest  in  a 
notch  made  in  the  seam  of  a  jDlain  band 
cemented  on  one  of  the  central  incisors. 
Its  use  is  indicated  when  the  desired 
movement  is  an  extensive  one  for  wliich 
the  available  anchorages  are  insufficient, 
such  as  (1)  when  the  lower  jaw  has  not 
to  be  moved  forward ;  (2)  the  upper 
molars  and  premolars  have  not  to  be 
moved  medially ;  and  (3)  when  the  upper 
arch  has  not  to  be  expanded. 

The  canines  will  be  moved  distally 
through  the  medium  of  ligatures.  A 
ligature  engages  each  tooth  to  be  so 
moved ;  it  must  also  engage  a  spur,  soldered 
to  the  bow  and  directed  backwards  just  behind 
the  distal  surface  of  the  canine.  The  nuts 
on  the  bow  must  be  removed  or  turned  well 
forward,  so  as  not  to  engage  the  anterior 
end  of  the  buccal  tubes,  or  else  the  force 
exerted  by  the  head-gear  will  be  transferred  to 
the  molars.  Should  this  be  desired  the  nuts 
are  used  and  adjusted  so  tliat  the  front  part 


217 


of  the  bow  will  not  be  in  contact  with  the 
incisors. 

Carl  B.  Case  (2)  describes  a  cervical  anchorage 
whereby  a  horizontal  (directly  backwards) 
pull  on  incisor  teeth  may  be  obtained — as  com- 
pared with  the  upward  and  backward  movement 
that  results  from  the  use  of  occipital  anchorage. 
In  cases  of  open  bite  the  latter  is  useful  when 
applied  to  the  lower  incisors,  but  is  contra - 
indicated  for  the  upper  teeth,  which  would  be 
pulled  backwards  and  made  shorter  by  such 
treatment ;  it  is  in  such  cases  that  cervical 
anchorage  is  indicated. 

In  the  same  article,  an  impi'oved  form  of 
head-gear  is  described,  the  attachment  of  elastic 
bands  to  wliicli  is  much  simplified ;  accessory 
appliances  which  permit  of  occipital  or  cervical 
force  being  exerted  on  the  incisors,  canines,  and 
molars,  either  individually  or  collectively,  are 
also  referred  to. 

SIEGFRIED   SPRING 

This  is  a  powerful  butterfly  spring  made  of 
very  fine  steel  wire.     (See  Figs  329  and  324.) 


Fig.  329. — Siegfried  spring. 
Arranged  to  move  a  lateral  labially ;    it  must  at  the 
same    time   move    the    central   medially  and    the 
canine  distally. 

A.  Labial  view. 

B.  Cross  section. 

C.  Sagittal  section  of  the  lateral. 

1.  Right  central. 

2.  Right  lateral. 

3.  Right  canine. 

(a)  Plain  band  on  (2),  to  which  is  soldered  a 
spur  {b)  to  carry  the  body  of  the  spring  (c). 

(d)  The  ends  of  the  wings  of  the  spring  held  in 
position  on  the  tooth  by  the  ligatures  (e). 

Its  use  is  almost  entirely  limited  to  the  labial 
or  lingual  movement  of  one  or  two  teeth,  the 
anchorage  for  w  liicli  is  obtained  from  the  teeth 
immediately  adjacent,  one  or  two  on  each  side 
of  the  misplaced  teeth  according  to  the  amount 


and  type  of  anchorage  required  (the  wings  are 
made  in  two  lengths  to  engage  one  or  two  teeth 
on  each  side  of  the  tooth  on  which  the  spring 
is  fixed) ;  if  simple  anchorage  is  desired,  then  a 
sufficient  number  of  teeth  (probably  one  on 
each  side)  arc  used  to  obtain  it ;  if  reciprocal 
anchorage  is  desired,  the  total  resistance  offered 
by  each  tooth  or  set  of  teeth  moving  in  opposite 
directions  shoidd  be  approximately  equal.  The 
spring  is  attached  to  a  suitable  spur  on  a  plain 
band ;  the  w  ings  are  arranged  to  impinge  on 
the  teeth  that  are  to  be  moved  in  the  direction 
opposite  to  that  on  which  the  spring  is  fixed. 
They  should  be  held  in  place  by  a  silk  or  wire 
ligature  engaging  the  loop  at  the  end  of  the 
.spring  and  the  tooth  on  which  it  rests. 

JACKSON    APPLIANCES 

Wheeler  (11)  writes  in  strong  support  of  this 
form  of  appliance  which  is  especially  indicated 
for  young  children.  His  arguments  are  very 
similar  to  those  advanced  in  support  of  remov- 
able appliances  in  general.  Jackson's  appli- 
ances and  methods  are  dealt  with  at  some 
length  in  the  Transactions  of  the  International 
Dental  Congress,  1909  (4),  and  a  still  fuller 
exposition  is  to  be  found  in  Jackson's  book  (5). 

THE  MOVEMENT  OF  THE  ROOTS  OF  TEETH 

It  has  been  shown  liow  the  roots  of  molars 
may  be  moved  at  the  same  time  and  in  the 
same  direction  as  the  crowns  by  means  of  an 
oval  buccal  tube  (or  other  device  that  permits 
translational  movement  only).     (See  p.  180.) 

As  regards  incisor  roots  a  similar  movement 
is  not  usually  desired.  More  frequently  the 
roots  have  to  be  moved  labially  whilst  the 
crowns  remain  stationary  or  even  have  to  be 
moved  linguaUy.  The  best-known  method  is 
by  means  of  the  Case  Contouring  Apparatus. 
The  principle  of  this  has  already  been  de- 
scribed and  illustrated  (see  p.  157).  The 
details  of  construction  and  use  are  as  follows. 
A  molar  clamp-band  with  buccal  tube  is  fi.xed 
in  such  alignment  that  the  bow  will  rest  at  the 
junction  of  the  median  and  incisal  edges  of  the 
crowns  of  the  central  incisors.  Before  the  band 
is  cemented  a  second  tube  is  soldered  to  the 
first  one  or  to  the  band  itself  if  possible,  in 
such  alignment  that  a  second  bow  will  rest 
at  the  junction  of  the  middle  and  lower 
third  of  the  root  of  the  central  incisors.  For 
the  teeth  whose  roots  are  to  be  moved  plain 
bands  are  made,  and  to  the  labial  surface  of 
these  special  spurs  are  soldered^ — one  to  be 
engaged  by  the  outer  aspect  of  the  upper  bow 
(upper  incisors  are  being  considered),  and  the 
other  to  be  engaged  by  the  dental  aspect  of 
the  lower  of  the  two  bows.  Li  the  case  of  the 
lower  bow  the  nut  is  placed  at  the  distal  end 


218 


of  the  tube  so  that  by  turning  it  against  the 
tube  the  tendency  is  to  pull  the  crown,  especially 
at  the  incisal  edge,  palatally ;  in  the  case  of 
the  other  bo^^•  the  nut  is  placed  as  usual  at  the 
front  of  the  tube  so  that  when  it  is  turned  the 
effect  is  to  move  the  root  of  the  tooth  forward, 
the  spur  engaging  the  bow  being  f)rolonged 
rootwards,  so  that  this  will  result.  Thus 
the  amount  of  labial  movement  of  the  root 
and  lingual  movement  of  the  crown  is  under 
complete  control.  The  direction  of  the  two 
forces  of  stress  and  traction  may  of  course  be 
reversed,  so  as  to  produce  forward  movement 
of  the  crowns  and  backward  movement  of  the 
roots  of  the  incisors 

Korbitz  (6)  has  described  a  modification  of 
this  appliance  A\hereby  cnly  the  upper  of  the 
two  bows  is  used  and  the  lower  one  is  replaced 
by   a    short    bow,    extending    from    canine    to 


are  soldered,  the  precise  direction  of  these  being 
at  right  angles  to  the  long  axis  of  the  tooth. 
In  the  case  of  two  approximal  teeth  inclined 
in  opposite  directions,  the  anchorage  is  recipro- 
cal (see  Fig.  330,  A).  When  only  one  tooth  has 
to  be  moved,  two  others  are  used  as  anchorage  ; 
the  latter  will  then  be  simple  anchorage  {see 
Fig.  330,  B). 

To  bring  about  movement  a  straight  section 
of  thin  pianoforte  wire  (having  more  spring 
than  platinized  gold  it  is  almost  to  be  i^referred 
in  this  case,  though  the  precious  metal  is  not 
to  be  regarded  as  inefficient  for  this  purpose)  is 
made  to  enter  all  the  tubes.  This  wire  endea- 
vours to  assume  its  original  form — straight — , 
the  result  being  to  straighten  the  two  teeth, 
that  is,  to  move  them  so  that  their  long  axes 
are  almost  parallel.  As  the  teeth  straighten, 
the  piano  wire  is  replaced  by  another  piece  of 
larger  gauge,  and  this  is  con- 
p  tinued  until  the  largest  size  that 

will  enter  the  tube  has  been  used. 
At  the  end  of  treatment  this  may 
serve  as  the  retention ;  but  it 
would  be  better  to  substitute 
platinized  gold  for  this  purpose 
and  to  solder  it  to  one  of  the 
bands. 

LIGATURES 

To  secure  the  greatest  effici- 
ency, ligatures  must  be  tied  with 
care  and  consideration.      If  the 
bow  is  almost  at  the  neck  of  the 
Fig.   330. — Inclination  movement  of  incisors.  tOOth,  the  ligature  will  fall  into 

(a)  Plain  bands,  to  wliicli  are  soldered  (6)  horizontal    tubes,  in    which      its  correct  position  on  the  tOOth 
(c)  spring  wire  is  placed.     (After  Kobbitz.)  jj^  tlie  case  of  the  centrals  and 

laterals,    at   times   also    of   the 


canine,  and  terminating  in  a  hook,  from  which 
a  rubber  band  may  be  stretched  to  the  buccal 
tube  (for  the  upper  bow)  on  the  molar  clamp- 
band.  This  short  bow  rests  in  the  notch,  as 
did  the  complete  bow.  The  forward  or  labial 
movement  of  the  roots  is  no\\  under  absolute 
control  as  before  ;  the  lingual  movement  of  the 
crowns  is  controlled  by  a  rubber  band  stretched 
between  the  points  already  referred  to,  and 
according  to  its  size  and  tension  the  operator 
controls  the  position  of  the  crowns  of  the 
teeth — whether  they  shall  move  lingually  or 
remain  stationary ;  in  the  latter  case  the 
rubber  band  has  to  be  of  just  such  strength 
that  it  will  counteract  the  force  developed  by 
the  bow  in  carrying  the  roots  forward. 

The  Movement  of  the  Roots  of  Incisors 

Korbitz  describes  a  simple  method  of  moving 
the  roots  of  teeth  in  medio-di.stal  directions. 

The  teeth  to  be  moved  are  banded ;  to  the 
labial    surface  of    the  bands  horizontal  tubes 


canine,  though  it  may  sometimes  be  necessary 
to  flace  it  at  the  neck  of  the  tooth.  If  a 
ligature  slips  off  the  tooth  incisally,  either  the 
bow  is  too  near  the  incisal  edge,  or  the  tooth 
is  conical  and  must  be  banded,  such  band 
having  a  spur  lingually  to  retain  the  ligature 
in  position.     (vSec  Fig.  337.) 

Silk,  Wire,  and  Rubber  Ligatures. — It  is 
always  desirable  in  moving  teeth  that  the 
simplest  method  to  effect  the  object  in  view 
should  be  used,  and  small  degrees  of  rotation 
and  other  movements  can  often  be  achieved 
by  the  use  of  ligatures,  especially  when  two 
adjacent  teeth  need  rotating  and  the  applica- 
tion of  force  is  reciprocal  in  its  effects.  For 
this  purpo.se  rubber  ligatures  are  very  efficient, 
but  they  have  the  disadvantage  of  being  apt 
to  slip  towards  the  necks  of  the  teeth  and 
injure  the  periodontal  membrane.  Some  oper- 
ators recommend  the  attachment  of  rul)ber 
ligatures  to  the  teeth  •\\ith  a  very  adhesive 
cement ;  or  the  cement  may  be  applied  to  the 


219 


tooth  and  a  groove  made  in  it  before  setting 
for  the  rubber  to  rest  in.  It  is  but  rarely  that 
rubber  should  be  used  without  being  attached 
to  a  wire  bow  or  other  appliance.  The  same 
objection  applies,  to  a  somewhat  less  extent, 
to  wire  ligatures;  and  fine  silk  is  by  far  the 
best  material  for  use  without 
other  appliance.  Its  method 
of  application  is  admirably 
described  and  illustrated  by 
C.  S.  Case  in  his  work  on 
Dental  Orthopcdia.  as  fol- 
lows— 

"  Silk  and  linen  thread 
have  been  used  for  all  time 
in  the  regulation  of  teeth, 
but  the  honour  is  due  to 
Dr.  W.  J.  Younger,  no\\-  of 
Paris,  for  first  practically 
demonstrating  the  remark- 
able effectiveness  of  very 
small  silk  ligatures,  and  for 
special  methods  of  securing 
them  to  teeth  to  obtain  the 
greatest  possible  advantage 
of  their  qualities. 

"  For  malturned  teeth 
that  require  a  slight  rotating 
force  for  their  correction, 
and  for  the  prevention  of 
rotation  movement  from  the 
action  or  misapplication  of 
other  forces,  Corticelli  A  silk 
ligatures,  if  properly  ap- 
plied, will  be  found  invalu- 
able. The  retention  of  a 
rotating  ligature  when  tied 
to  a  tooth,  and  its  subse- 
quent potential  action,  is 
due  quite  as  much  to  the 
resilient  quality  — •  foiuid 
only  in  the  smallest  of  silk 
threads — as  to  the  method 
of  its  application.  An  im- 
portant advantage  of  the 
smaller  sizes  is  also  their 
greater  freedom  from  be- 
coming foul,  so  common 
with  the  larger  ligatures. 

"  To  tie  a  silk  ligature  to  a 
tooth,  that  will  not  slip  while 
exerting    a    rotating   force, 
requires  special  methods  of 
procedure.     (See  Fig.  3:^1.) 
First :  the  ligature  should  be  thoroughly  waxed 
except  at  that  portion  of  the  middle  which  is 
sufficient  to  pa.ss  twice  around  the  tooth  to  be 
rotated.     Second  :    pass   the   iniwaxed   portion 
twice  around  tlie  tooth  and  form  the  first  half 
of  the  knot  by  passing  one    end   through    the 
loop  twice  and   even  three  times,  to  ])revent  it 


from  slipping  after  drawing  it  tightly  to  place. 
Third  :  while  grasping  the  ends  of  the  ligature 
firmly,  lift  the  tie  from  the  tooth  with  all  the 
force  which  the  ligature  will  bear  (see  '  a  '), 
then  suddenly  drop  the  hands  while  keeping 
up  the  tension,  to  take  up  all  the  slack  (.see  "  b  '). 


Fig.  331. — Methods  of  application  of  silk  ligatures  to  produce  various  movements. 
a,  b,  and  c.  Method  of  tying  {see  text). 
1,  2,  3,  and  4.  Different  rotations  of  centrals. 

5.  Rotation  of  left  central  and  right  lateral  in  same  direction. 

6.  Rotation  of  laterals  in  opposite  directions. 

7.  Elongation  of  left  Central. 
S.  Depression  of  left  central.     (C.  S.  Case  :  Dental  Orthopcdia.) 

By  repeating  this  movement  once  or  twice 
it  ensures  drawing  the  double  loop  round 
the  tooth  to  its  fullest  tension.  Fourtli  :  the 
balance  of  the  knot  is  fuii.shed  by  passing  the 
end  through  the  loop  ovce,  either  way,  and 
drawing  it  firmly  to  place  with  a  slight  right 
and    left    movement    (see    'c').       Fifth:     the 


220 


double   strand   is   grasped   and   carried   in   the 
direction  of  the  desired  force." 

Silk  and  wire  ligatures  are  not  made  to  encircle 
a  tooth  by  passing  them  between  the  appro ximal 
surfaces,  but  by  threading  them  through  the 
inter-dental  space.  In  the  case  of  silk  ligatures 
a  double  strand  of  floss  silk  is  passed  into 
the  inter -dental  space  that  the  ligature  is  to 
occupy ;  the  silk  ligature  is  made  to  engage  the 


Fig.  332. — The   continuous  ligature. 
Especially    applicable    for    holding    lower    incisors    in 
their  new  positions  whilst  the  bow  is  still  worn. 
(After  KiJRBiTZ.) 

loop  in  the  floss  silk,  which  is  now  pulled 
through  the  inter-dental  space,  bringing  with 
it  the  ligature  silk ;  it  is  placed  in  the  other 
space  in  the  same  way  and  then  tied  in  a  simple 
Imot  or  as  described  above.  The  ligature  and 
field  of  operation  should  be  kept  dry.  (See 
pp.  221,  226.) 

The  threading  of  ivire  ligatures  usually 
presents  no  difficulty ;  when  some  trouble  is 
experienced  the  end  of  the  \\  ire  may  be  flattened 
in  the  joint  of  the  pliers,  and  thus  flattened 
may  be  cut  to  a  point ;  this  often  facilitates 
the  passage  of  the  ligature  through  the  space. 
Frequently  it  is  advisable  to  give  the  end  of 
the  ligature  wire  a  curve,  so  that  it  will 
take  the  desired  direction  through  the  space 
and  not  enter  the  gum.  Occasionally  it  is 
impossible  to  pass  a  wire  ligature  between  the 
teeth ;  especially  is  this  so  when  one  or  both 
teeth  are  rotated  and  have  assumed  such  posi- 
tions that  the  contact  between  them  extends 
to  and  below  the  gum  margin.  In  such  cases 
it  will  be  found  that  after  movement  of  teeth 
has  been  obtained  it  will  be  possible  to  adjust 
a  thin  wire  ligature,  or  a  silk  ligature  may  be 
used  if  it  is  urgent  that  the  movement  be  started. 
A  wire  ligature  should  be  9  to  12  ins.  long,  so 
that  when  it  is  round  the  tooth  and  one  arm 
is  above  and  the  other  below  the  bow,  the  two 
ends  may  be  firmly  grasped,  one  in  each  hand, 
and  pulled  —  one  upwards  and  one  down- 
\\'ards — so  as  to  cross  the  bow  at  right  angles. 
The  two  arms  of  the  ligature  are  then  rotated 
so  that  the  wire  crosses  itself,  being  kept  as 
close  as  possible  to  the  patient's  face  and  neck. 
A  three-quarter  turn  in  this  mamier  will  make 
the  ligature  secure.  It  is  well  to  make  the  turn 
in  the  same  direction  in  every  case,  so  that 
when  they  are  tightened  the  turn  \\ill  always 
have  to  be  made  in  the  same  direction.  The 
excess  wire  may  then  be  cut  off  so  as  to  leave 
an  end  yV  in-  to  v  in-  long,  which  is  tucked 
under  or  over  the  bow  so  as  to  be  out  of  the 


way  and  free  from  any  outside  influence  liable 
to  disturb  it  from  its  position.  The  ^v^iter 
prefers  to  continue  the  twisting  of  the  ligature 
beyond  the  three-quarter  turn  for  about  four 
turns,  so  that  when  the  excess  is  cut  off  one 
strand  only  remains,  ■\\hich  is  i  in.  long  and 
may  be  tucked  into  a  suitable  po.sition,  from 
which  it  is  not  at  all  likely  to  be  displaced  on 
account  of  its  rigidity  (see  Fig.  327). 

When  the  lo\\er  incisors  have  only  to  be  held  en 
bloc  in  position  against  the  bow,  the  continuous 
ligature  of  Korbitz  (7)  may  be  employed.  It 
has  the  advantage  of  securing  the  four  teeth 
without  an  increase  of  wire  between  the  teeth, 
and  with  only  one  knot  (see  Fig.  332). 

For  special  ligatures  for  deciduous  molars 
and  for  premolars  see  p.  207,  and  Fig.  322, 
and  p.  208,  respectively. 

To  renew  the  effect  of  a  ligature  a  new  one 
should  only  be  ajiplied  when  the  previous  one 
breaks.  Till  this  happens  the  ligature  in  use 
is  tightened  by  means  of  How's  pliers,  whose 
beaks  are  curved  to  prevent  the  lips  being 
pinched  and  Mhose  ends  are  smooth  and  meet 
at  a  .slight  angle   (see  Fig.  333).     The  end  of 


Fig.  333. — How's  Pliers  with  smooth  enlarged  ends 
well  adapted  for  tightening  ligatures.  The  beaks 
(a)  are  ciu'ved  so  as  not  to  pinch  the  lips ;  (6)  is  a 
full  view  of  one  beak. 


the  ligature  that  is  to  be  tightened  is  straight- 
ened out  and  gripped  in  the  pliers  (whose  beaks 
must  be  smooth,  or  else  there  will  be  great 
liability  of  cutting  the  wire).  At  the  same 
time  the  bow  and  tooth  are  pressed  together 
with  the  finger  and  thumb  of  the  other  hand, 
and  the  ligature  is  tightened  sufficiently  to  en- 
sure further  tooth  movement  without  the  pro- 
duction  of    pain ;    an  intelligent    patient   can 


221 


always   assist    the    operator     by    saying    how 
much  the  ligature  may  be  tightened. 

ON  FORCE  AS  REGARDS  THE  MOVEMENT 
OF  TEETH 

Force  for  orthodontical  purposes  may  be 
continuous  or  discontinuous. 

The  usual  means  of  applying  continuous  force 
consist  chiefly  of  the  flexural  elasticitj^  of  steel 
or  gold  \\ire,  and  the  extensional  or  com- 
pressional  elasticity  of  rubber.  Wue,  whetlier 
in  tlie  form  of  a  bow  or  as  applied  to  individual 
teeth,  is  capable  of  many  modifications,  and 
rubber  is  employed  in  many  different  ways  for 
moving  single  teeth,  or  on  a  larger  scale  for 
the  so-called  inter-maxillary  force.  Short  j^ieces 
of  coiled  wii'e  attached  by  silk  ligature  may  be 
used  so  as  to  act  in  a  manner  similar  to  rubber. 

The  expansion  of  wood  by  absorption  of 
moisture  is  also  an  example  of  continuous  force, 
althougli  only  \\ithm  certaui  limits.  The  fact 
that  the  amount  of  expansion  is  small  does  not 
affect  the  principle,  because  the  application  of 
force  is  gradual  and  progressive  and  not  sudden, 
as  in  the  case  of  the  screw. 

The  inclined  plane,  i.  e.  an  artificial  plane 
inclined  to  tlie  plane  of  occlusion  fixed  to  one 
or  more  teetli  of  either  jaw,  and  arranged  so 
that  one  or  more  of  the  teeth  of  the  opposing 
jaw  impmge  upon  it,  takes  advantage  of  the 
natural  forces  of  occlusion  and  mastication. 
It  Ls  an  example  of  intermittent  use  of  what 
would  be  a  continuous  force  if  the  teeth  were 
maintained  in  contact. 

The  most  important  agents  of  discontinuous 
force  are  the  screw  and  wvce  ligature,  that  is 
to  say,  when  applied  from  a  more  or  less  rigid 
base  and  not  from  an  elastic  wire  bow,  or  in 
connection  with  it. 

The  screw  is  perhaps  the  most  generally 
useful  means  at  disposal  and  is  capable  of 
almost  unlimited  application,  from  the  simple 
jack-screw,  or  traction-screw,  to  the  expansion 
bow  and  elaborate  system  of  bars  and  bow  in 
which  screw-force  is  only  or  mainly  employed. 
Wire  ligatures  are  sometimes  given  as  examples 
of  continuous  force,  but  in  reality  the  extensional 
elasticity  of  wire  is  but  little  used,  and  the 
action  ceases  as  soon  as  absorption  has  com- 
pensated for  compression  of  the  periodontal 
membrane. 

Rigid  wires  may  be  shortened  or  lengthened 
in  situ  with  the  aid  of  pliers.  Shortenmg  may 
be  produced  by  accentuating  a  pre-existent 
bend,  or  by  creating  a  new  bend  or  "  step  "  as 
described  by  Case.  Lengthening  may  be  pro- 
duced by  pinchuig  the  « ire  at  intervals  througli- 
out  its  length  as  described  by  Angle.  Each  of 
these  methods  is  an  example  of  discontinuous 
force. 


The  only  agent  commonly  used  that  combines 
in  its  application  continuous  and  discontmuous 
force  is  the  fibrous  or  silk  ligature.  When  first 
tiglitly  applied  it  acts  in  the  same  way  as  a 
w  ire  ligature,  but  absorption  of  moisture  causes 
shortening  of  the  ligature,  and  m  this  way 
contmuous  force  for  a  limited  period  is  super- 
imposed on  discontinuous.  The  great  efficiency 
of  sUk  ligatures,  even  of  very  fine  calibre, 
probably  depends  upon  this  combination  of 
forces.  Auotlier  method  by  which  continuous 
and  discontinuous  action  miglit  be  combined 
would  be  to  make  part  of  the  length  of  a  traction 
screw  slightly  sinuous  or  helical.  By  this  means 
the  screw  could  be  screwed  up  more  tightly  and 
the  extensional  elasticity  of  the  helical  rod 
brought  into  play,  so  that  the  risk  of  damage  by 


Fig.  334. — A  diagram  to  show  tho  effect  of  tying  teeth 
to  a  flexible  wire  bow.  The  bow  is  pulled  in  where 
the  ligatures  are  tied,  and  bulges  out  in  the 
intervals ;  tliis  results  in  a  constant  effort  on 
the  part  of  the  bow  to  resume  its  normal  shape, 
and  so  also,  in  the  movement  of  tho  teeth  that  are 
tied.     {Dental  Record.) 

over-tightenmg  would  be  reduced.  The  elas- 
ticity of  a  wire  bow  in  combination  with  a 
screw  acts  in  a  similar  way. 

The  Principle  of  Buccal  or  Labial  Movement  of  a 
Tooth  by  Fixed  Appliances. — When  fixed  appli- 
ances are  used  and  ^^•ire  ligatures  are  employed 
to  connect  the  teeth  and  bow,  it  must  not  be 
thought  that  the  ligatures  are  the  important 
factor  in  tooth  movement;  they  are  little  more 
than  tlie  means  whereby  force  is  transmitted 
from  the  wire  bow  to  the  teeth.  Take  for  ex- 
ample the  laljial  movement  of  a  central  incisor. 
The  bow  is  adjusted  in  the  buccal  tubes  on 
the  anchor  bands,  so  that  the  nuts  engage  the 
front  of  the  tubes  and  the  bow  stands  away 
from  the  tooth  to  the  extent  of  from  one  to 
two  millimetres.  A  wire  ligature  is  applied 
to  the  tooth  and  tightened  round  it  and  the 
bow.  One  effect  of  this  is  to  cau.se  tlie  bow, 
which  is  constructed  of  springy  wire,  to  be 
pulled  in  towards  the  tootli  (see  Fig.  334) ;  this 


222 


spring-Avire  bow  is  constantly  tending  to  resume 
its  normal  shape  after  the  tying  of  the  ligature, 
and  in  so  doing  it  must  bring  the  tooth  for- 
ward as  it  regains  its  original  shape.  Another 
effect  of  the  application  of  the  ligature  is  due 
to  the  compressibility  of  the  tissues  in  ■which 
the  tooth  is  held.  The  force  exerted  by  the 
bow  on  the  ligature  is  transmitted  to  the 
intervening  tissues,  and  as  a  result  the  tissues 
are  compressed  and  the  tooth  has  been  subjected 
to  a  slight  but  nevertheless  aijpreciable  im- 
mediate movement ;  further  movement  without 
any  alteration  at  all  in  the  arrangement  or 
adjustment  of  the  appliances  is  the  result  of 
the  spring  of  the  bow  endeavouring  to  spend 
itself.  It  is  thus  seen  that  the  ligature  in 
itself  is  not  the  source  of  any  force  ;  it  is  simply 
a  medium  for  the  transmission  of  force.  A\lien 
the  spring  of  the  bow  has  spent  itself  no  more 
tooth  movement  is  to  be  expected,  but  the 
force  of  the  spring  can  be  quickly  redeveloped 
in  one  of  two  ways :  Firstly,  by  tightening  the 
wire  ligature,  and  this  may  be  done  again  and 
again  until  the  bow  and  tooth  are  in  contact 
(unless  the  ligature  has  to  be  renewed  on  account 
of  its  breakage).  Secondly,  by  turning  the 
nuts  of  the  bow  against  the  front  of  the  buccal 
tubes  so  as  to  bring  the  bow  further  away  from 
the  front  of  the  teeth  ;  if  the  ligatures  are  in 
situ  when  this  is  done,  it  has  the  effect  of  tighten- 
ing them  by  causing  the  bo^^■  to  be  pulled  in 
towards  the  tooth  from  its  normal  alignment. 
If  the  ligatures  are  not  in  situ  then  the  entire 
bow  is  moved  bodily  forward  so  that  the  pro- 
cess is  continued  as  when  a  ligature  was 
originally  applied. 

It  is  tluis  seen  that  when  the  expansion  bow 
is  properly  used  tooth  movement  is  due  to  its 
spring  and  the  compressibility  of  the  tissues. 
The  ligatures  and  the  screws,  -when  either  are 
tightened,  are  only  to  develop  and  transmit 
the  force. 

Wien  the  bow  is  pulled  in  towards  a  tooth 
it  is  caused  to  bulge  elsewhere,  and  if  there 
are  other  ligatures  it  is  obvious  that  this  bulging 
effect  will  tighten  these  (see  Fig.  334). 

The  action  of  a  screw  may,  however,  be 
obtained  when  a  very  rigid  instead  of  springy 
bow  is  used.  In  an  instance  of  this  sort,  if 
a  central  incisor  is  in  contact  with  the  bow 
and  the  two  are  tied  together,  the  effect  of 
turning  the  nut  against  the  tube  is  immediately 
to  carry  the  tooth  forwards  in  proportion  as 
the  nut  is  turned.  In  the  previous  case,  i.  e. 
when  a  spring  bow  is  used  in  contradistinction 
from  a  rigid  bow,  the  amount  of  force  exerted 
on  the  centrals  when  the  nuts  are  turned  against 
the  fronts  of  the  tubes  does  not  increase  to  the 
same  extent  as  it  would  with  a  rigid  bow,  on 
account  of  the  bulging  of  the  wire  bow  at  the 
sides ;  but  the  length  of  time  over  which  a  bow 


;  so  adjusted  acts  would  be  increased  in  jiroportion 
as  the  nuts  are  turned. 

Rubber  ligatures  as  used  do  not  exert  enough 
force  to  pull  in  the  bow  so  that  it  shall  exert 
spring,  nor  are  they  capable  of  compressing  the 
tissues  to  obtain  immediate  movement.  Their 
effect  is  solely  due  to  their  j)roperty  of  retum- 
mg  to  their  original  size  and  shape ;  and  so 
their  use  in  conjunction  ^\'ith  the  spring  bow 
ignores  the  princijjles  that  make  this  appli- 
ance so  valuable.  They  may,  however,  be  of 
value  where  the  tooth  is  some  distance  from 
the  bow,  and  the   approximal   teeth   need   to 

j  be  moved   laterally  away  from   the   tooth   to 

i  which  the  rubber  ligature  is  applied,  as  this  will 
be  the  effect  of  the  rubber  in  the  inter-proximal 
spaces.  A  plain  band  with  suitable  attach- 
ment to  hold  the  rubber  band  in  correct  position 
on  the  tooth  is  usually  necessary  and  always 
desirable.  The  rubber  band  may  be  attached 
to  the  wire  bow  by  looping  it  on  itself. 

Rubber  wedges  act  in  the  same  ^\'ay — ^whether 
they  are  compressed  between  tooth  and  bow, 

I  or  tooth  and  wire  ligature  ;  as  the  bulk  of  rubber 
is  much  greater  than  in  the  previous  case  they 
may  have  a  slight  immediate  effect. 

TECHNIQUE 

The  technique  of  orthodontics  is  not  a  wide 
field ;  there  are  certain  fundamentals  that 
must  be  grasped,  and  then  it  only  remains  for 
the  individual  operator  to  employ  these  and 
combine  them  to  produce  the  most  varied  types 
of  appliances. 

The  principles  on  which  a  clamp-band  is 
constructed  have  been  stated  on  p.  173.  The 
details  that  follow  may,  however,  be  added. 
The  size  of  the  tooth  may  readily  be  obtained 
by  means  of  Herbst's  crown  bands,  as  used  for 
obtaining  the  diameter  of  a  root  to  be  crowned  ; 
the  band  material  should  be  cut  one  millimetre 
longer,  so  that  the  ends  of  the  completed  band 
overlap  when  it  has  been  finally  fitted  to  the 
tooth. 

Wlien  a  plain  or  soldered  band  has  to  be  made 
for  a  molar  or  jjremolar  the  same  method  should 
be  employed,  the  band  material  being  cut  a 
trifle  longer,  so  that  the  ends  of  the  band  may  be 
overlapped  for  soldering  purposes  on  the  same 
principle  as  the  Peeso  soldering  method  for 
bands  for  crowns  (see  p.  611),  except  that,  on 
account  of  the  thinner  metal,  it  is  not  essential 
that  either  of  the  ends  should  be  bevelled. 
Plain  bands  for  the  premolars  may  also  be 
made  with  the  band-forming  pliers,  as  in  the 
case  of  incisors  and  canines  (described  below). 
It  may  be  necessary  to  separate  a  tooth  to  be 
measured  and  banded  in  this  way  from  its 
neighbours  before  any  progress  can  be  made 
with  the  work. 


223 


Clamp-bands  that  are  too  long  can  only  be 
shortened  by  cutting  a  piece  out  of  the  length 
of  the  band  material ;  clamp-bands  that  are 
too  short  are  equallj-  impossible  as  practical 
appliances,  especially  when  they  are  for  pre- 
molars or  upper  molars.  The  markedly  convex 
lingual  surface  of  these  teeth  seriously  affects 
the  stability  of  the  band  even  if  it  can  be 
made  to  stay  on  the  tooth  at  all  satisfactorily. 
This  invariably  happens  if  the  band  is  so  short 
that  when  it  is  put  on  the  tooth  the  clamp- 
wire  is  contiguous  ^^ith  the  convex  lingual 
surface  of  tlie  tooth  and  has  to  take  the  place 
of  band  material ;  even  if  it  is  bent  t-o  con- 
form to  this  convex  surface,  that  frequently 
does  not  suffice  to  enable  the  operator  to  make 
the  band  remain  satisfactorily  on  the  tooth ; 
the  wire  is  so  umielding,  and  the  surface  with 
which  it  is  in  contact  so  inclined,  that  it  cannot 
be  made  to  stay  on  these  teeth  with  convex 
and  sloping  lingual  surfaces.  The  only  solution 
of  the  difficulty  is  to  use  a  band  of  larger  size. 

Bands  may  be  lengthened  a  little  by  means  of 
the  Peeso  stretching  and  contouring  pliers. 


Fio.   335. — Angle's  band-forming  Pliers  with  enlarged 
ends  having  tliree  straight  edges. 
(6)  A  full  view  of  the  face  of  the  beak  (a). 
(c)  Angular  slot  for  holding  nuts, 
(rf)  Circular  slot  for  holding  wire. 

On  the  incisors  and  canines  plain  bands  only 
are  used,  and  they  are  made  direct  to  the  natural 
tooth.  For  this  purpose  a  long  strip  of  metal 
is  taken  and  made  to  encircle  the  tooth  to  be 
banded  near  one  of  its  extremities.     The  short 


end  is  left  just  long  enough  to  be  grasped  on 
the  buccal  surface  of  the  tooth,  andwitii  it  the 
long  piece  of  band  material,  where  it  would  come 
in  contact  with  the  short  end,  is  grasped  between 


Fig.   336. — Instrument  for  carrying  a  plain  band  into 
position  on  a  tooth, 
angle   that   engages   the   angle   formed   by   tooth 
and   band  should   be  rectangular  and  not  acut« 
as  appears  in  the  diagram. 


Tl 


the  thumb  and  first  fuager,  and  the  material 
pulled  tight  round  the  tooth  ;  it  is  now  burnished 
to  the  liiigual  surface  to  make  it  lit  closely, 
the  pulling  making  it  fit  the  approximal  sur- 
faces. The  buccal  surface  alone  renutins  to  be 
fitted,  and  this  is  done  by  drawing  together  the 
surfaces  of  the  two  ends  of  the  band  nuiterial 
as  they  leave  the  approximal  surfaces  of  the 
tooth  with  any  pair  of  pliers  whose  beaks  are 
flat  and  smooth,  and  have  in  addition  .<quare 
edges,  so  that  the  two  pieces  of  material  are 
brought  into  contact  at  right  angles ;  any 
edge  of  the  pliers  may  be  used  so  long  as  it 
is  wide  enough  to  grasp  the  band  material  in 
its  entire  width  and  the  beaks  come  into  abso- 
lute juxtaposition,  so  that  the  two  pieces  of 
band  material  are  in  complete  apposition  «hen 
the  band  is  on  the  tooth.  The  Angle  band- 
forming  pliers  (see  Fig.  335),  and  the  Pullen 
band-forming  pliers  have  been  designed  for 
this  particular  purpose.  The  conical  shape  of 
the  canine  makes  it  desirable  to  bring  the  join 
on  the  lingual  surface  of  the  tooth  instead  of 
on  the  labial,  as  is  generally  done.  If  the  join 
must  be  labially,  then  a  piece  of  band  material 
must  be  taken  up  on  the  lingxutl  surface  by 
pinching  with  the  phers  towards  the  pointed 
end  of  the  tooth  and  filled  ^^ith  solder,  and  the 
excess  of  material  cut  off.  In  this  \\ay  a  well- 
fitting  band,  m  hose  cervical  edge  is  considerably 
longer  than  the  other,  is  obtained.  The  cervical 
edge  of  all  these  bands  should  be  as  near  the 
gum  margin  as  possible.  They  shoidd  not  fit 
the  tooth  too  closely,  or  else  there  will  be  no 
room  for  the  cement  on  which  their  retention 
is  largely  dependent.  -\n  instrument  suited 
for  tins  purpose  should  be  used  to  carry  plain 
bands  into  position  (see  Fig.  336). 


224 


The  next  step  in  the  construction  of  a  plain 
band  is  to  unite  the   two  projecting  surfaces 
with  solder ;    this  is   done   by  cutting  a  small 
square  of  plate  solder,  placing  it  between  the 
two   pieces  of    metal,   and   gripphig   all  three 
together  in  the  square-ended  beaks  of  a  pair 
of  tweezers  whose  extremities  have  been  bent 
at  right  angles  to  the  general  direction  of  the 
length  of  the  pliers  and  in  such  a  way  that 
when  the  beaks  of  the  pliers  are  closed  they 
come  into  accurate  contact  with  one  another. 
Borax  is  used  as  a  flux  for  the  solder ;  it  may 
be    prepared   in   the    ordinary   way   as   borax 
cream,  but  a  more  convenient  and  ever-ready 
form  is  that  obtained  by  incorporating  powdered 
dehydrated    borax    into    vaseline,    a    little    of 
which  is  apx^lied  to  the  surfaces  to  be  soldered 
as  well  as  to  the  solder.     It  has  the  additional 
advantage    of    causing    the    solder    to    remain 
where  it  is  placed.     A  liquid  flux,  a  solution 
of  borax,   etc.,   is   also   a   very  suitable   form. 
The  actual  soldering  is  best  done  by  a  blow- 
pipe flame  which   must   be   capable   of  giving 
a  concentrated  heat — that  is,  a  flame  that  is 
pointed  and   can  be   directed  on    to  the  part 
where  the  solder  is  to  flow.     Griinberg,  Lane, 
and    Lowe    Young    have    all    designed    stand 
blowpiiJes  especially  adapted  for  this  purpose, 
which  are  to  be  obtained  at  the  depots;    they 
all  admit  of  the  flame  being  obtained  in  more 
than  one  direction.     A  Melotte  blowpipe  gives 
a  very  suitable  flame,  but  the  operator  must 
adopt  means  to  secure  the  blowpipe  and  iiame 
in  the  desired  position,  because  it  is  one  that 
is  really  designed  to  be  held  in  the  hand.     An 
even  and  continuous  blast  of  air  is  essential, 
so  suitable  bellows — those  worked  by  a  back- 
ward and  forward  movement  of  the  foot  serve 
admirably — must   be   used   with  a  rubber  bag 
intervening   between   these  and   the  blowpipe. 
In  cases  of  soldering  like  that  under  consider- 
ation, the  bulk   of  metal  is  so  small  that   the 
pointed   flame    may   be    immediately   directed 
to  the  solder  and  the  parts  to  be  united.     In 
the  one  case    just  described  a  hand  blowpijie 
will  suffice,  but  probably  it  is  the  only  instance 
in  which  that  is  so.      Wlien   two    parts    that 
must  be  held  separately  are  to    be  united,  a 
blowpipe   in  a   fixed  position  is  necessary,  so 
that  the  hands  may  be  left  free  to  hold  them 
and  keep  them  in  contact.     In  fuiishing  the 
united  ends  of  plain  bands,  it  must  not  be  over- 
looked that  the  union  is  entirely  in  the  raised 
seam,  which  must  be  left  sufficiently  high  or 
long  to  give  the  union  strength.     This  finishing 
is  not  done  till  all  soldering  in  comrection  with 
the    band    has    been    completed,  when    stones 
and  discs  in  the  engine  are  used  to  smooth  the 
upstanding  edges  and   round   off  the   comers. 
The  seam  may  be  cut  as  a  notch  in  which  the 
bow  will  rest,  or  as  a  spur  to  hold  a  ligature 


near  the  neck  of  the  tooth.  The  latter  is 
chiefly  used  when  the  seam  is  placed  lingually ; 
otherwise  the  ligature  must  encircle  the  tooth 
twice. 

This  leads  on  to  the  next  step  in  regard  to 
bands — the  attachment  of  accessory  parts,  as 
spurs,  tubes,  etc.,  to  them.  The  first  step  is 
to  flow  the  required  amoimt  (almost  invariably 
very  small)  of  solder  on  to  the  larger  piece  and 
then  to  bring  the  two  parts  into  contact  in  the 
flame,  so  that  the  latter  just  reaches  the  solder 
and  the  two  surfaces  to  be  luiited.  Li  order 
that  these  may  be  kept  in  accurate  apposition 
the  hands,  or  rather  wrists,  should  be  supported 
on  the  table,  and  a  fuiger,  not  required  to  hold 
the  work,  of  each  hand  extended  so  that  they 
come  into  contact  and  support  one  another, 
thus  obviating  the  liability  of  the  hands  moving 
at  the  moment  when  soldering  is  about  to  talvc 
place.  Wlienever  possible  the  parts  should  be 
left    sufficiently   long    to    enable    them    to    be 


I 


Fig.  337. — Plain    bands. 

(a)  With  notcli,  cut  in  the  seam,  to  hold  the  bow. 

(6)  and  (c)  Medial  and  lingual  views  respectively  of 
band  with  spur  at  cervical  edge,  to  hold  ligature 
on  conical  or  partially  erupted  teeth. 

(d)  and  (e)  Axial  and  lingual  views  respectively  of 
band  with  spur  at  cervical  edge  and  inturned 
comer  of  tooth,  to  hold  ligature  for  rotation. 

comfortably  and  easily  held  in  the  fuigers, 
without  fear  of  burning  them  and  without 
the  intervention  of  tweezers.  Thus,  in  the 
case  of  a  plain  band  it  is  left  attached  to  the 
long  strip  of  metal  till  it  is  essential  it  should 
be  cut  off.  When  it  is  cut  off  the  next 
band  should  be  made  from  the  same  strip, 
and  as  close  up  to  where  the  first  one  was  as  will 
allow  the  second  band  to  be  accurately  conformed 
to  the  tooth  by  the  pliers. 

Wlien  soldering  on  a  spur,  a  length  of  wire 
is  employed  and  the  excess  cut  off  after  union 
has  been  obtained.  A  spur  or  hook  for  ortho- 
dontical  purposes  may,  as  a  rule,  consist  of  a 
straight  piece  of  wire  soldered  to  the  main  por- 
tion of  the  appliance  at  an  angle ;  it  is  rarely 
necessary  that  the  wire  composing  such  spurs 
should  be  bent  in  any  way.  Li  the  case  of  tubes 
they  have  to  be  held  in  pliers,  which  should  grip 
the  tubing  at  the  extremities.  Overheating 
must  be  guarded  against  in  all  cases,  especially 
when  using  German  silver  and  when  platinized 


225 


gold  tubes  are  being  soldered  to  bands,  as  tlie 
heat  and  pressure,  if  at  all  more  than  sufficient 
to  flow  the  solder,  may  cause  the  metal  to  bend. 
The  use  of  pliers  \\  hen  soldering  on  tubes  may 
be  avoided  by  soldering  to  the  tube  a  piece  of 
V  ire,  which  will  enable  the  tube  to  be  indirectly 
held  in  the  fingers.  This  wire  is  cut  ofi  \\hen 
the  work  is  completed. 

20  carat  solder  should  be  used  on  platinized 
gold  appliances  ;  w  hen  a  low  er  carat  is  necessary 
for  additional  accessories  "  00  "  solder  may  be 
used.  This  lower  grade  solder  is  desirable  for 
spurs  on  bows.  Silver  solder  is  used  on  German 
silver  appliances  except  for  attachments  to  the 
bow,  \\  hen  sfift  solder  must  be  used,  as  the  heat 
would  take  the  temper  out  of  the  bow.  Nuts 
should  be  removed  before  heating  an  appliance. 

Apparatus  has  been  designed  to  hold  two 
small  pieces,  which  are  to  be  united  by  solder, 
in  the  desired  apposition.  PuUen  (10,  p.  724) 
uses  a  series  of  five  clamps ;  they  are  of  such 
shapes  that  any  two  parts  of  a  band  may  be 
securely  held  during  the  process  of  soldering. 
Another  device  for  this  purpose  consists  of  an 
appliance  with  a  smaU  sc^e^^-clamJ)  at  either 
end,  whilst  in  the  intervening  portion  there 
are  several  universal  joints,  which  enable  the 
extremities  to  be  brought  into  every  possible 
relation  with  one  another. 

To  obtain  Fixed  Points  on  Bows 

Spurs  on  Platinized  Gold  Bows. — A  tin}'  piece 
of  solder  is  run  on  the  bow  \\here  the  spur  is  to 
be  attached  ;  then  a  length  of  spur-wire,  not 
greater  than  gauge  10,  is  attached  at  this  point, 
the  free  end  being  in  the  direction  towards  w  hich 
the  tooth  is  to  be  moved  or  in  which  the 
resistance  is  required. 

Spurs  on  German  Silver  Boios. — In  this  case 
the  spur  is  made  from  brass  ligature  wire, 
gauge  26  or  28;  a  little  ball  of  soft  solder  is 
run  on  the  end  of  the  wire  and  then  attached 
to  the  bow  ;  the  heat  used  to  do  this  must  be 
the  least  possible  or  the  temper  will  be  taken 
out  of  the  bow  and  its  spring  lost,  so  rendering 
it  useless. 

Li  both  cases  the  excess  wire  is  cut  off  and  the 
spur  left  just  long  enough  to  hold  the  ligature. 
The  free  end  is  rounded  with  a  stone  or  disc 
in  the  engine. 

Notches  in  ribbed  bows  are  cut  with  a  knife- 
edged  file,  so  that  the  ligature  may  be  held  in 
the  required  positit)n.  Care  must  be  taken 
that   only   the   rib   is   cut. 

Hooks  on  the  Bow  for  hiter-maxillari/  Force. 
In  the  ease  of  platinized  gold  bows  the  hook  is 
a  suitable  bent  })iece  (  f  wire  attached  direct  to 
the  bow  (see  Fig.  338  (3)). 

In  tlic  case  of  fJ«^rmnn  silver  bows  on  which 
.soft  si'ldcr  must  be  used,  this  form  of  attach- 
ment is  less  secure,  and  instead  the  spur  should 
8 


be  hard  soldered  to  a  short  length  of  tubing 
which  is  in  turn  soft-soldered  to  the  bow  (see 
Fig.  338  (1)).  This  necessitates  the  removal  of 
the  nuts. 

To  avoid  this,  Pullen  solders  the  spur  to  a 
small  piece  of  band  material,  which  has  been 
cut  and   bent   so   as  to   represent  a  piece   of 


:^:zi= 


b 
I 

Fig.  338." 


'6  b 

2  3 

-Forms  of  hook  for  application  of  inter- 
maxillary force. 


(a)  Wire  bow. 

(6)  Spur,  hard-soldered  to 

(c)   tubing,  which  is  soft  soldered  to  (a). 


(d)  Half-tubing,    or   band   material    similarly   shaped, 
soft-soldered  to  (o).     (After  Puxlen.) 

3.  1 

(6)   Spur  directly  soldered  to  (a)  at  (e)  with  hard  solder. 

Methods  1  and  2  are  applicable  to  German  silver  bows, 
and  3  to  platinized  gold  bows. 

tubing  cut  in  two  lengthways.  Soft  solder  is 
attached  to  the  inside  of  this  half  tube,  which 
is  now  soldered  to  the  bow  (see  Fig.  338  (2)). 

THE    CONSTRUCTION    OF    APPLIANCES 

Appliances,  whether  foi  moving  teeth  or  for 
retaining  them,  must  be  made  with  absolute 
accuracy.  Clamp-bands  with  buccal  tubes  at- 
tached and  bows  are  the  only  appliances  to 
be  had  ready  made.  Almost  every  other 
appliance  must  be  made  for  each  individual 
case ;  each  part  must  be  accurately  made  in 
itself  and  in  relation  to  the  other  parts  in 
conjunction  with  which  it  will  work.  Bands 
having  been  made  and  fitted  as  required,  a  cast 
is  needed  that  will  give  the  exact  relation  of 
all  the  parts  and  the  bands  in  position.  This 
is  obtained  for  preference  from  a  plaster  impres- 
sion (one  of  composition  will  often  answer  the 
purpose  if  carcfullj^  made)  taken  with  the  bands 
on  the  teeth.  The  impression  having  been 
removed  from  the  mouth  and  dried  or  hardened, 
the  bands,  after  removal  from  the  teeth,  are 
replaced  in  the  impression,  which  is  now  cast 
in  sand  and  plaster.  This  model  is  then  used  in 
order  to  solder  tlie  various  accessories  to  the 
main  parts  of  the  appliance.  This  pioiedure  is 
cspocially  ap]>licable  to  the  (onstruotion  of 
retaining  appliances. 

It  may  happen  that  a  retaining  appliance  has 
to  be  repaired  hurriedly ;  for  instance,  a  band 
to  which  a  buccal  or  lingual  retaining  wire  is 


226 


soldered,  has  broken  and  has  to  be  made  anew. 
The  wire,  with  any  bands  that  may  be  attached 
to  it,  is  removed  from  the  mouth ;  the  broken 
band  is  detached  from  the  rest  of  the  appliance 
and  a  new  one  made  to  replace  the  broken  one. 
The  retaining  wire  is  replaced  in  the  mouth, 
ligatures  being  used  to  support  it  against  the 
teeth  if  necessary.  A  sand-and-plaster  impres- 
sion is  now  taken  so  that  the  parts  to  be  united 
are  accurately  held  in  it,  but  no  impression 
material  is  allowed  to  come  in  contact  with  those 
parts  that  are  to  be  soldered  together ;  if  it  does 
this  must  be  removed,  and  soldering  proceeded 
■n-itli  at  once.  In  this  ^\'ay  a  repair  may  be  done 
whUe  the  patient  is  in  the  chair.  All  edges  of 
bands  or  wire  should  be  smoothed  and  rounded 
with  stones  or  discs  before  the  appliance  is 
cemented  in  the  mouth. 


SIZES  OF  MATERIALS   USED  IN  ORTHODONTICS 
Clamp-bands 


Band  Material. 

Length. 

Tliickness. 

Width. 

Permanent 
Molars  and 
Premolars. 

Deciduous 
Molars. 

Platinized 
gold  .     . 

27,  30,  33, 
and  36  mm. 

■18  mm. 

5  mm. 

4-5  mm. 

German 
silver 

30  mm. 
and  two 
other  sizes 

•18  mm. 

5  mm. 

45  mm. 

Tubes. — The  size  of  the  tubes  should  be  such 
that  the  bows  fit  them  accurately.  This  is 
essential  for  the  efficiency  of  the  apparatus. 
One  firm  manufactures  all  its  bows,  of  which 
there  are  five  sizes,  so  that  the  threaded  ijortion 
is  the  same  size  in  all,  only  the  intermediate 
portion  of  the  bow  being  variable.  Li  this  way 
only  one  size  of  tube  is  necessary.  These  same 
bows  have  the  threaded  portion  flattened,  so 
that  it  accurately  fits  the  oval  or  round  tube 
(see  Fig.  280).     Buccal  tubes  are  -J  inch  in  length. 

The  Clamping  Mechanism.  —  Gauge  16  wire 
is  used  to  make  the  threaded  wire ;  the  nut  and 
tube  are  of  a  size  to  correspond. 

Plain    Bands.  —  The  length  of  these  is  such 


that  they  fit  the  tooth  accurately  and  yet  not 
absolutely  tightly,  or  else  there  will  be  no  room 
for  the  cement  on  which  their  retention  on  the 
tooth  depends  as  well  as  on  their  fit. 


Material. 

Thickness. 

Width  for 

Incisors. 

Permanent 
Molars. 

Deciduous 
Molars. 

Iridio- 
platinum . 

•08  mm. 
•14  mm. 

3^6  mm. 

4-0  mm.  suitable  for  any  tooth 

Platinized 
gold    .     . 

•18  mm. 
•10  mm. 

5'0  mm.     4-0  mm. 
4  0  mm. 

German 

silver '  .     . 

C 

F 

H 

•10  mm. 
•14  mm. 
•14  mm. 

4-0  mm. 
4^0  mm. 
5^0  mm. 

As  regards  the  use  of  precious  metals  for 
plain  bands,  platinized  gold  is  to  be  preferred 
for  molars  and  premolars  when  they  are  to  be 
used  as  anchorage  for  moving  teeth ;  it  is 
softer  than  iridio-platinum,  and  is  therefore 
more  satisfactorily  worked  and  burnished. 
This  point  is  of  practical  imf)ortance  because 
molar  and  premolar  bands  for  anchorage 
purposes  must  be  thicker  and  stronger  than  for 
retention  or  holding  ligatures,  and  must  be 
more  or  less  burnished  to  fit  the  tooth.  In  the 
case  of  plain  bands  for  incisors  and  premolars 
(when  not  for  anchorage),  these  may  be  thinner 
and  narrower ;  for  this  reason  they  should  be 
made  of  iridio-platinum,  which  is  tougher  than 
platinized  gold,  and  in  these  circumstances  can 
be  satisfactorily  burnished,  if  they  do  not  already 
fit  the  tooth  accurately  by  the  simple  tightening 
of  the  material  round  it  with  pliers. 

Ligatures. — Ligatures  are  of  brass  wire,  gauges 
26, 28,  and  30  (B.  &  S.) ;  26  gauge  is  the  one  most 
used  when  the  patients  are  not  more  than  ten 
years  old.  Above  that  age,  and  when  bows, 
gauge  16,  are  being  used,  gauge  28  wire  is  indi- 
cated ;  the  30  gauge  wire  is  seldom  needed. 

Silk  ligatures  are  discussed  elsewhere.  Tliree 
sizes  should  be  kept  ready  for  use.     (See  p.  218.) 

The  use  of  rubber  bands  of  various  sizes  for 
inter-maxillary  force  is  discussed  by  Pullen  (9). 

1  The  letters  refer  to  the  material  sold  by  the  S.  S. 
White  Company. 


CHAPTEE    X 


ABNORMALITIES   OF  POSITION— TREATIMENT   {continued) 


RETENTION 

E.  How,  and  for  how  long,  are  these  move- 
ments to  be  artificially  retained  (retention)  ? 

General  Principles. — If  possible  the  retention 
of  teeth  in  their  new  positions  is  of  greater 
importance  than  the  moving  of  teeth,  on  account 
of  the  very  great  tendency  they  exhibit  to 
return  to  their  former  positions.  The  object 
of  retention  is  to  combat  this  tendency.  The 
necessity  for  retention,  natural  or  artificial, 
exists  in  every  case ;  it  occasionally  happens 
that  natural  retention  ■\\ill  suffice,  but  it  may 
be  taken  for  granted  that  these  cases  are  so  few 
in  number  as  to  be  negligible,  and  that  the 
operator  errs  on  the  right  side  in  retaining 
unnecessarily. 

It  has  been  pointed  out  that  the  two  dental 
arches,  whether  normal  or  abnormal,  tend  to 
harmonize  in  size  ;  if  there  has  been  coiLsiderable 
movement  of  the  upper  and  lower  teeth,  the 
tendency  of  both  to  relapse  is  more  or  less  equal. 
Before  treatment  these  dental  arches  harmonize 
in  size,  and  at  the  conclusion  thereof  they  have 
been  made  to  harmonize  again  in  size,  and  so, 
if  both  are  not  carefully  and  efficiently  retained, 
they,  the  new  arches,  will  show  a  strong  ten- 
dency to  collapse  together,  and  again  exliibit 
those  features  which  most  marked  the  original 
irregularity.  Especially  is  it  necessary  for  one 
arch  to  be  absolutely  retained,  \\hen  any  ten- 
dency to  relapse  shown  by  the  other  arch  may 
be  combated,  if  even  for  a  time  only,  by  the 
one  that  is  securely  held.  This  leads  up  to 
those  cases  in  wliich  only  one  arch  has  been 
treated,  the  other  remaining  exactly  as  it 
presented.  This  untreated  arch  may,  therefore, 
be  regarded  as  a  stable  unit  and  one  that  will 
materially  a.ssist,  passively  of  course,  in  the 
retention  of  the  other — i.  e.  it  will  offer  natural 
retention ;  but  artificial  retention  is  also  neces- 
sary, because  a  relapse  would  most  certainly 
occur  unless  the  teeth  had  very  prominent 
cusps  correctly  occluding  with  those  of  the 
opposite  jaw  in  which  there  had  been  no  move- 
ment, and  unless  equilibrium  had  been  estab- 
lislied  between  all  the  tis.sues  involved. 

Retention  must  be  maintained  until  equi- 
librium  has  been   established;    this   does   not 


take  place  till  all  the  tissues — bone  and  soft 
tissues — ^have  developed  and  accommodated 
themselves  to  correspond  \\ith  the  new  positions 
of  the  teeth.  The  teeth  have  been  moved  to 
occupy  the  positions  they  would  have  occupied 
had  the  jaws  developed  normally ;  these  move- 
ments are  carried  out  nuich  more  rapidly  than 
bone  and  muscle  can  develop  their  normal  form 
and  function,  and  until  this  takes  place  natural 
retention  is  not  to  be  ex]5ccted.  ^\'hen  it  does 
result,  permanent  and  natural  retention  may 
be  said  to  have  been  established,  and  it  will  be 
readily  understood  that  the  younger  the  patient 
the  more  quickly  will  it  take  place ;  at  six  to 
eight  years  of  age  it  may  be  expected  to  occur 
in  six  months  or  so,  whereas  at  sixteen  years  of 
age  a  less  satisfactory  state  will  obtam  after 
three  years  of  artificial  retention.  (The  extent 
and  direction  of  tooth  movement  also  have  a 
bearing  on  this  point.)  Until  natural  retention 
has  been  established  there  mil  be  a  tendency — 
more  or  less  great  according  to  the  extent  to 
which  artificial  retention  lias  been  successfully 
carried  out — for  the  bone  and  adjacent  soft 
tissues  to  resume  their  former  state,  and  in  so 
doing  the  teeth  ■^^■ill  be  carried  with  them  to 
occupy  their  former  malpositions.  It  is  the 
function  of  retention  to  combat  this  tendency. 

Retention  is  the  holding  of  teeth  in  their  new 
positions  until  the  surrounding  tissues  have 
accommodated  themselves  perfectly  to  the 
teeth  in  those  positions.  Mechanical  resistance 
in  the  form  of  apj)lianccs,  usually  passive  but 
occasionally  active,  is  employed  to  retain  teeth 
much  in  the  way  that  force  was  used  to  move 
the  teeth.  This  resistance  must  be  sufficient, 
or  else  there  will  be  a  greater  or  less  relapse 
according  to  the  amount  of  the  insufficiency 
of  the  resistance. 

Natural  retention  is  the  result  of  inter- 
digitation  of  cusps,  both  medio-distally  and 
bucco-lingually,  as  well  as  of  the  normal 
function  of  the  lips  and  cheeks  buccally  and  the 
tongue  lingually. 

Anchorage  deals  with  the  resistance  of  teeth 
to  movement ;  retention  also  deals  \rith  the 
resistance  of  teeth  to  movement.  In  the  former 
it  was  resistance  to  obtain  movement  that  was 
dealt  '.\ith ;  in  the  latter  it  is  resistance  to 
prevent  movement  that  has  to  be  considered. 


227 


228 


Retention  may  be  considered  under  the  same 
headings  as  Anchorage. 

((«)  Simplest. 
-(b)  Reinforced. 
[(c)  Resistance    to    transla- 
tion. 
1(a)  Simplest. 
\(h)  Reinforced. 
( Imjjracticable    as    a    force 
t         for  retention. 


A.  Simple 

B.  Reciprocal 

C.  Stationary 


Any  of  those  included  in  A  and  B  may  also 
be  inter-maxillary,  i.  e.  may  act  between  the 
two  jaws. 


Fio.  339. — Retention — simplest  reciprocal  ancliorage.  Two 
upper  central  incisors  misplaced  in  opposite  directions, 
one  labially  and  the  other  lingually. 

A.  Before  treatment. 

B.  and  C.     After  treatment  with  retainers  in  position. 

B.  Plain  band  on  the  lingually  misplaced  central  with  labial 
spur  to  the  other  central  to  hold  the  latter  lingually, 
which  is  reciprocally  holding  the  former  labially. 

C.  Plain  band  on  the  labially  misplaced  central  with  lingual 
spur  to  the  other  central  to  hold  the  latter  labially,  which 
is  reciprocally  holding  the  former  lingually. 

In  addition  to  these  purely  artificial  methods 
of  retention,  natural  retention  may  be  active 
to  some  extent  as  soon  as  the  tooth-moving 
appliances  are  removed. 

A.  Simple. —  (a)  The  Simplest  Retention  is 
that  in  which  a  larger  and  stronger  tooth  will 
resist  the  tendency  of  a  smaller  one  to  return  to 
its  former  position,  e.  g.  a  molar  will  be  sufficient 
resistance  to  prevent  a  premolar  relapsing. 
As  the  force  required  to  retain  a  tooth  is  less 
than  that  required  to  move  it,  a  tooth  of  low 


resistance  value  will  frequently  suffice  to  retain 
one  of  greater  resistance  value  (see  Fig.  360). 

(b)  Reinforced  Retention  is  similar  to  (a),  but 
two  or  more  teeth  are  employed  instead  of  one ; 
e.  g.  a  central  and  lateral  wUl  retain  an  inter- 
vening central. 

(c)  Resistance  to  Translation. — A  molar  that 
can  only  move  by  translational  movement  will 
be  of  greater  retaining  value  than  if  it  were 
capable  of  movement  by  inclination. 

B.  Reciprocal. — (a)  Simplest.  Two  incisors 
that  have  been  moved  in  opposite  directions 
will  retain  one  another  if  suitably  opposed 
(see  Fig.  339). 

(b)  Reinforced  is  that  form  of  retention  in 
which  several  teeth  that  have  been  moved 
are  employed  to  retain  teeth  that  have 
been  moved  in  the  opposite  direction,  e.  g. 
buccal  movement  of  the  molar  series  on 
opposite  sides  of  the  same  jaw. 

C.   Stationary   Retention   is   that   derived 
from  the  occiput  and  associated  bones. 

Retaining  Appliances 

Having  to  exert  passive  force  only,  re- 
taining appliances  should  be  much  simpler, 
in  design  than  appliances  for  moving  teeth. 
They  must,  however,  be  strong  and  well 
constructed,  as  they  are  to  be  worn  a 
considerable  time,  during  \\  hich  they  must 
be  efficient  without  the  need  of  constant 
attention.  Their  strength  as  regards  retain- 
ing the  teeth  has  only  to  be  sufficient 
to  ensure  that  they  will  not  be  overcome 
by  the  tendency  of  the  teeth  to  relapse,  so 
that  the  younger  the  patient  the  lighter 
may  be  the  appliance  ;  just  as  a  weaker  or 
lighter  appliance  will  move  the  teeth  of  a 
young  patient  than  would  be  required  for 
an  older  one.  It  must  be  remembered, 
however,  that  retaining  appliances  are 
often  constructed  to  engage  the  lingual 
surfaces  of  the  teeth  (whereas  tooth-moving 
apphances  are  more  frequently  on  their 
buccal  sin-faces)  where  the  effects  of  masti- 
cation will  be  more  severe  on  them  than 
on  the  other  class  of  apiiliances,  and  they 
must  be  designed  with  this  fact  in  mind. 
Following  the  course  adopted  with  tooth- 
moving  appliances,  devices  to  retain  teeth 
in  their  new  positions  may  be  classified  as — ■ 

A.  Fixed. 

B.  Removable. 

A.  Fixed. — Fixed  appliances  are  to  be  pre- 
ferred, because  they  may  be  simple  and  con- 
structed to  exliibit  the  highest  degree  of 
efficiency.  They  are  not  apt  to  damage  the 
soft  tissues,  as  is  always  likely  to  occur  with 
vulcanite  plates.  Above  all,  they  are  out  of  the 
patient's  control  and  must  be  worn,  whereas  a 
removable  appliance  is  likely  to  be  forgotten 


229 


or  even  lost;    the  result  of  this  would,  in  all 
probability,  be  disastrous. 

These  appliances  should  be  constructed  so 
that,  as  far  as  possible,  the  various  parts  are 
separate  from  one  another,  and  thus  allow  the 
repair  or  renewal  of  any  one  jiart  without  dis- 
mantling the  entire  appliance.  They  must 
receive  support  from  attachments  fixed  to 
teeth,  which  are  placed  at  closer  intervals  than 
is  necessary  in  the  case  of  appliances  to  move 
the  teeth,  ^hen  two  clamp-bands,  one  on  each 
first  molar,  are  sufficient  to  hold  and  firmly 
support  a  wire  bow,  because  they  are 
supplemented  by  ligatures.  Ligatures  are 
undesirable  in  comiection  ^\ith  retaining 
appliances,  so  definite  additional  support 
from  a  band  on  an  intervening  tooth  must 
be  given  to  a  retaining  bo^\  that  is  attached 
to  two  first  molars  or  even  two  second 
premolars.  As  has  been  already  men- 
tioned, a  lingual  wire  is  also  nuicli  more 
exposed  to  stresses  that  result  from 
mastication  than  a  buccal  arch ;  this  is 
another  reason  why  extra  support  is 
necessary.  Li  the  case  of  retaimng  ap- 
pliances a  free  end  of  wire  may  extend 
beyond  the  actual  attachment,  but  it  must 
be  rigid  and  shoidd  not  include  more  than 
one  tooth,  as  the  free  end  is  likely  to  be 
bent,  if  at  all  prolonged,  by  the  repeated 
stress  put  upon  it  (see  Fig.  341). 

Fixed  Appliances  consist  of — 

1.  Bands,  plain  or  clam]),  with  spurs 
soldered  to  them  (see  Figs.  3-41,  344, 
360). 

2.  \Mre  bo^\s,  complete  or  partial,  at- 
tached to  (1)  (see  Figs.  344,  356). 

Plain  bands  are  more  commonly  em- 
ployed, as  they  are  simpler  and  their 
attachment  to  the  teeth  by  cement  usually 
suffices.  The  bands  in  one  jaw  are  united 
by  wire  attachments  so  arranged  that  they 
will  resist  the  tendency  of  the  teeth  to 
return  to  their  former  jjositions  (see  Figs. 
344,  356). 

Wire    used    for    retention,   \\hether    it 
includes  one  tooth  or  a  number  of  teeth,  and 
whether  removable  or  fixed,  should  only 
touch  the  teeth  at  their  most  prominent  i^oints 
unless  othenA'ise  necessary  for  special  reasons ; 
it    is    not    good    practice    to    fit    these    \\ires 
accurately  round  the  exposed  surfaces  of  the 
teeth. 

The  following  tj'pes  of  attachment  may  be 
used  to  unite  bands  and  wires — 

(i)  The  main  retaining  wire  is  soldered  direct 
to  a  band  (see  Fig.  356  (2)  ). 

(ii)  The  wire  bow  engages  a  loop  on  the  band, 
both  being  arranged  and  situated  so  as  to  be  a 
source  of  strength  to  the  appliance  (see  Fig.  341). 
To  maintain  the  correct  relation  between  wire 


bow  and  loop  a  lug  on  the  former  may  be 
necessary  (see  Fig.  341). 

(iii)  The  wire  enters  a  tube,  closed  or  per- 
forate ;  when  the  latter  form  is  used  it  may  be 
essential  to  solder  a  lug  on  the  wire,  or  to  have 
the  wire  threaded  and  carrying  a  nut,  which 
shall  engage  one  of  the  extremities  of  the  tube 
(see  Fig.  340). 

There  is  great  advantage  in  appliances  of 
this  type  because  they  permit  of  slight  indi- 
vidual movement  of  the  teeth,  allowing  them  to 
take  up  a  position  of  equilibrium,  whilst  main- 


n 


Q, 


p      - 


3. 


Fig.  340. — Methods  of  movable  attachment  between  short  tubes 
and  retaining  wires. 

1.  Retaining  wire  entering  a  closed  tube.  The  object  of  the 
closed  end  is  to  enable  the  tooth  to  wliich  the  tube  is 
attached  to  resist  any  pressure  brought  against  it  by  other 
teeth  exerting  pressure  on  the  lingual  wire.  The  attach- 
ment on  the  first  left  molar  (see  Fig.  356)  could  be  of  this 
nature  and  would  resist  anj'  tendency  of  the  incisors  to 
move  lingually  were  there  no  attacliment  to  the  first  left 
premolar. 

1.  Retaining  wire  passing  through  a  perforate  tube  with  lug 
on  the  wire  to  serve  the  same  purpose  as  the  tube  with 
closed  end.  The  attacliment  on  the  second  right  premolar 
(Fig.  356)  could  be  of  this  nature.  The  object  of  the  wire 
passing  through  the  tube  is  to  retain  the  adjacent  molar  in 
its  buccal  position. 

Retainmg  wire  passing  tlirough  a  perforate  tube  and  then 
bent  over.  The  buccal  attaclunent  on  one  or  both  sides 
to  the  second  premolar  (see  Fig.  'Hi,  III),  could  be  of  this 
nature.  The  incisors  would  in  this  way  be  prevented 
from  moving  labially.  The  wire  used  with  this  object  in 
view  must  be  sufficiently  thin  to  be  easily  bent  when  the 
appliance  is  in  the  mouth. 

Tlireaded  wire  passing  through  a  perforate  tube,  one  end 
of  which  is  engaged  by  the  nut  on  the  wire.  The  applica- 
tion of  this  method  is  shown  in  Fig.  341.  This  type  of 
attaclunent  has  the  advantage  of  being  adjustable.  W^hen 
cii'cumstances  demand,  the  nut  may  engage  the  distal  end 
of  the  tube ;  its  fixation  in  the  mouth  would  be  more 
difficult. 

taining  their  general  relationship  to  one  another. 
Li  the  text,  soldering  all  the  parts  to  the  base 
wire  is  assumed,  to  avoid  constant  repetition, 
but  it  must  be  bonie  in  mind  that  it  is  preferable 
not  to  attach  the  ^\ire  rigidly  to  all  the  bands 
unless  this  is  specially  referred  to. 

B.  Removable. 

liemovable  Appliances  consist  of — - 


1.  Vulcanite  Plates; 

2.  Metal  plates  of  tlie  same  tjiie  as  vulcanite 

plates,  or  of  the  Jackson  type  with  a 
skeleton  base ; 


230 


3.  Plates  combining  the  features  of  (1)  and 
(2)  (see  Figs.  342,  343). 

Wire  attachments  are  used  in  connection 
with  the  plates  when  necessary,  and  may  be 
fixed  directly  to  the  teeth  or  to  the  plate ;  the 
former  method  implies  a  combination  of  fixed 


Fig.  341. — Retention  of  buccal  movement  of  all  the 
teeth. — Reciprocal  reinforced  and  .simple  reinforced 
anchorage. 

The  retainer  consists  of  a  lingual  wire  and  plain  bands 
with  accessories  on  5  ]  15.  The  wire  is  not  soldered 
to  any  of  the  bands. 

On  the  right  premolar  band  the  accessory  is  a  short 
tube,  engaged  medially  by  a  nut  on  the  lingual  wire, 
which  in  this  position  is  threaded ;  on  the  left 
premolar  band  the  accessory  is  a  wire  loop  to  engage 
the  lingual  wire,  on  which  there  is  a  lug  engaging  the 
loop.  The  lug  and  nut  prevent  lingual  movement 
of  the  incisors. 

A  cross-section  of  the  left  central  incisor,  having 
cemented  to  it  a  plain  band  with  loop,  before 
closing,  and  lingual  wire  in  position,  is  shown  on 
the  right  of  the  figure.  The  gingival  end  of  the 
loop  is  left  free  so  that  if  the  loop  is  not  efficient 
a  wire  ligature  may  engage  this  free  end  and  the 
lingual  wire  to  secure  the  two  together.  Notice 
that  the  loops  are  arranged  diagonally  across  the 
tooth,  whereby  they  are  longer  and  so  more 
easily  adjusted. 

and  removable  appUances,  which  is  frequently 
a  desirable  plan. 

Attachments,  whether  removable  or  fixed, 
.  should  be  made  for  preference  to  deciduous 
teeth. 

The  tooth  movements  to  be  retained  are 
the  same  as  those  referred  to  on  p.  181.  This 
part  of  the  subject  need  not  be  dealt  with 
seriatim  as  tooth  movement  has  been  treated, 
but  the  table  given  for  that  purpose  (p.  182) 
wUl  now  be  followed  in  the  case  of  retention, 
and  the  numbers  used  refer  to  it. 

I  and  n— MOLARS.   PREMOLARS,   CANINES, 
AND  INCISORS 

A.  Buccal  Movement 
1,   3,   5,    7,    and    3S.     Fixed   Appliances. 
(a)   (See  Fig.  344,  I,  without  the   labial  wire 


from  canine  to  canine.)  Clamp  or  plain  bands 
are  fitted  to  the  first  permanent  molars  and  plain 
bands  to  the  canines.  A  complete  lingual  wire 
bow  is  bent  up  to  fit  the  dental  arch  almost  at 
the  necks  of  the  teeth,  and  then  soldered  to  the 
lingual  surfaces  of  the  four  bands.  If  the 
clamping  portion  of  the  clamp-band  extends 
forwards  then  the  lingual  wire  bow  is  attached 
to  this ;  if  it  goes  distally,  the  lingual  wire  is 
attached  to  the  medio-lingual  comer  of  the 
band.  Wlaere  there  has  been  considerable 
buccal  movement  of  the  canines  this  arrange- 
ment of  the  bands  is  desirable,  as  the  efficient 
retention  of  these  teeth  is  very  important, 
especially  in  the  upper  jaw. 

(6)  (See  Fig.  341.)  Plain  bands  are  made 
for  the  two  second  premolars  and  for  one  of 
the  incisors,  the  one  selected  having  been 
moved  lingvially  or  moved  least  in  a  labial 
direction.  A  lingual  wire  is  bent  up  so  that  it 
will  hold  all  the  teeth  as  desired ;  it  may  be 
maintained  in  place  without  solder  if  constructed 
as  follows.  To  the  lingual  surface  of  one  pre- 
molar band  a  short  horizontal  tube  is  soldered 
(when  fixing  the  appliance  in  the  mouth  it  may 
be  necessary  to  put  this  band  on  last,  even 


Fig.  342.  —  Vulcanite  saddle  retention  plate  with 
platinized  gold  wire  to  hold  the  incisors  in  their 
labial  positions.  There  are  accessory  wires  soldered 
to  the  main  base-wire  to  engage  those  tooth  surfaces 
that  are  next  to  the  spaces  for  the  uneiupted 
canines,  so  that  these  spaces  may  be  preserved. 
The  wire  on  the  first  right  premolar  is  also  a  spring 
to  move  that  tooth  distally.  The  wire  on  the  left 
lateral,  which  has  been  rotated,  is  bent  round  to 
engage  the  labial  surface  of  that  tooth  closely,  and 
hold  it  in  its  new  position ;  the  lingual  wire  against 
the  lingual  surface  of  the  tooth  holds  the  other 
comer.  There  are  wire  clasps  on  the  first  permanent 
molars  to  hold  the  plate  in  position. 

after  the  lingual  wire  has  been  put  in  ;  the  tube 
on  the  band  is  slipped  over  the  end  of  the  wire 
and  then  the  band  itself  rotated  into  place  on 
the  tooth) ;  one  end  of  the  lingual  bow  sliould 
be  threaded  and  carry  a  nut  to  engage  this  short 
tube  medially  (see  p.  238  (3));   the  wire  then 


231 


passes  across  the  lingual  surfaces  of  all  the  teeth, 
being  engaged  by  loops,  open  occlusal  ly  and 
soldered  to  bands,  one  on  an  incisor,  preferably 
a  central,  and  the  other  on  the  other  second 
premolar.  To  maintain  the  medio-distal  posi- 
tion of  the  -wire  a  lug  is  soldered  to  it  to 
engage  the  loop  on  the  premolar  so  that  it 
cannot  slip  distally  through  the  loop ;  this  also 
secures  the  retaining  \\ire  in  position  against 
the  incisors,  Mliich  are  now  prevented  from 
relapsing  in  a  lingual  direction. 

These  loops  shoidd  be  placed  as  near  the 
cervical  edge  of  the  tooth  as  possible  and  be 
open  only  sufficiently  to  permit  the  bow  wire  to 
pass,  or  else  there  will  be  the  possibility  of  the 
patient  dislodging  it  with  the  tongue.  If  of 
sufficient  length  and  made  of  thin  wire  (19  gauge 
B.  &  S.),  these  loops  may  be  closed  after  the 
lingual  bow  is  in  position.  The  lug  to  engage 
the  medial  aspect  of  the  loop  on  the  premolar 
may  be  given  an  inclination  distally,  ■\\hen  it 
will  also  act  as  a  locking  device.  If  there  is 
any  difficulty  in  maintaining  the  wire  bow  in 
position  it  may  be  tied  to  the  loops  by  a  fine 
wire  ligature  of  brass  or  gold.  The  incisor  loop 
is  more  applicable  to  the  lower  jaw  than  the 
upper,  where  the  use  of  any  appliance  but  that 
occupjing  the  least  space  (the  wire  soldered  to 
the  band)  may  be  contra-indicated  on  account 
of  the  bite. 

(c)  (See  Figs.  345  and  350.)  Labial  move- 
ment of  the  incisors  and  canines  may  be 
retained  by  banding  the  first  premolars  or 
canines  and  joining  the  two  bands  by  a  lingual 
wire ;  if  the  canines  are  banded  the  wire  may 
be  extended  distally  to  include  the  first  pre- 
molars if  it  is  necessary  to  retain  those  teeth 
in  position. 

2,  4,  6,  8,  and  39.  Removable  Appliances. 
(See  Fig.  342.)  A  simple  plate,  metal  or  vul- 
canite, is  made  to  engage  all  the  teeth  to  be 
retained  on  their  lingual  surfaces.  It  may  be 
held  in  position  by  clasps  or  cribs  on  molars 
or  premolars. 

In  the  case  of  the  upper  jaw,  if  all  the 
teeth  have  to  be  retained  at  one  time,  the 
plate  may  be  a  saddle  one  with  a  platinized 
gold  wire  attached,  at  both  extremities,  to 
the  anterior  edge  of  the  plate,  and  passing 
round  beliind  the  incisors  and  canines  to  en- 
gage these  teeth  at  a  point  just  beyond  the 
free  edge  of  the  gum.  Wlien  necessary,  addi- 
tional attachments  may  be  soldered  to  this 
lingual  wire. 

In  the  case  of  the  lower  jaw  a  similar  principle, 
but  varied  to  meet  the  different  conditions,  may 
be  employed  (see  Fig.  343).  The  sides  of  the 
plate  are  made  in  vulcanite  or  metal  as  usual 
to  retain  these  teeth,  and  these  two  portions  of 
the  plate  are  coiuiected  by  an  oval  wire,  as  used 
in  making  wire  lower  dentures,  passing  across 


the  lingual  surfaces  of  the  canines  and  incisors  so 
as  to  rest  on  the  cingula  of  these  teeth.  Methods 
such  as  these  considerably  reduce  the  amount 
of  soft  and  hard  tissue  covered  by  tlie  plate, 
and  so  there  is  less  liability  of  any  harm  being 
caused  thereby. 

In  some  cases  it  will  he  possible  to  replace 
vulcanite  in  contact  with  tlie  jiremolars  by  wire. 


Fig.  343. — Vulcanite  and  metal  retention  plate.  The 
sides,  in  the  position  of  the  premolars  and  molars, 
are  of  vulcanite ;  the  intervening  portion  is  an  oval 
wire  resting  on  the  eingnla  of  the  incisors.  On  the 
right  lower  molar  there  is  a  cleat  to  prevent  the 
plate  sinking ;  on  the  base  wire  there  is  a  spring 
to  push  out  the  two  central  incisors.  Against  the 
distal  surface  of  the  first  left  premolar  there  is  a 
sliort  spur  to  prevent  that  tooth  falling  distally. 
On  the  first  left  molar  there  is  a  complete  crib 
clasp. 

which  will  still  further  reduce  the  amount  of 
tissue,  covered  by  plate,  that  there  is  any 
possibility  of  damaging. 

B.  Lingual  Movement. 

9,  11,  13,  15,  and  40.  Fixed  Appliances. 
This  is  the  reverse  of  that  just  described,  but  it 
seldom  involves  more  than  individual  teeth, 
except  in  the  case  of  the  upper  incisors.  For 
this  purpose  a  wire  must  extend  from  canine 
to  canine  or  more  distal  teeth,  on  their  labial 
surfaces.  In  many  cases  expansion  of  the 
molar  series  and  canines  will  also  have  to  be 
maintained  at  the  same  time.  The  ways  in 
which  the  appliances  may  be  arranged  for  this 
purpose  are  numerous ;  tho.se  shown  in  Fig.  344 
may  be  mentioned. 

(I)  is  probably  the  mo.st  efficient  ;  the  lingual 
wire  behind  the  incisors  is  to  give  added  strength 
and  to  remove  any  chance  of  the  molar  series 
collapsing,  and  the  labial  wire  may  be  a  very 
light  one^  The  cases  in  w  hicli  these  movements 
have  to  be  retained  are  usually  complicated  by 
close  bite,  so  that  there  is  every  probability  of 
the  lower  incisors  striking  this  lingual  wire ;  if 
it  serves  the  purpose  of  opening  the  bite  this 


232 


arrangement  is  satisfactory,  but  it  throws  con- 
siderable strain  on  the  canine  bands. 

(II)  and  (III)  avoid  the  use  of  a  lingual  wire 
for  the  incisors.  The  retention  of  the  buccal 
movement  of  the  molar  series  and  canines,  as 
well  as  of  the  lingual  movement  of  the  incisors, 
depends  entirely  on  a  buccal  wire,  which  must 
therefore  be  of  heavy  iridio-platinum ;  the  short 


Fig.  344. — Upper  arch,  which  has  been  expanded  in  the 
molar  and  canine  regions.  The  incisors  have  been 
moved  lingually.  Retention — Reinforced  recipro- 
cal and  simple  reinforced. 

I.  Clamp-bands  on  the  first  molars  ;  plain  bands  on  the 

canines ;  a  lingual  wire  bow  from  molar  to  molar  to 
retain  all  the  teeth  except  the  incisors,  which  are 
retained  in  their  lingual  positions  by  a  labial  wire 
from  canine  to  canine. 

II.  Plain  bands  on  first  molars,  first  premolars,  and  one 

central ;  a  complete  buccal  wire  from  molar  to 
molar.  This  retains  all  the  teeth  as  desired  except 
the  second  premolars,  which  are  held  buccally  by 
lingual  spurs  from  bands  on  the  molars  or  pre- 
molars. If  the  canines  need  retaining,  lingual 
spurs  must  extend  to  these  also,  (a)  Shows  the 
arch  resting  in  a  notch  in  the  seam  of  the  central 
band  instead  of  being  soldered  to  it. 

III.  Plain  bands  on  the  second  premolars  and  central, 
to  all  of  which  a  buccal  wire  is  soldered.  To  each 
premolar  band  a  lingual  wire  is  soldered,  which 
engages  the  first  molar,  first  prertiolar,  and  canine. 

In  I,  II  and  III  the  incisors  are  held  lingually  by  the 
canines  and  premolars  (also  by  the  molars  in  I  and 
II),  whose  position  has  not  been  changed  in  the 
direction  (medio-distal)  that  corresponds  to  bucco- 
lingual  direction  of  movement  of  the  incisors,  as 
regards  their  efficiency  for  retention  purposes. 


Fig.  345. — Retention  of  lingual  movement  of  incisors 
by  combined  labial  and  lingual  wires,  the  required 
resistance  being  obtained  from  the  canines. 

Anchorage — Simple  reinforced. 

Plain  bands  on  the  canines  and  one  central ;  a  lingual 
wire  unites  the  three  bands.  A  labial  wire  is 
attached  to  the  central  band  and  engages  all  the 
incisors  that  have  to  be  held  in  a  lingual  position. 
Without  the  labial  wire  this  appliance  will  hold 
the  incisors  labially. 

lingual  .spurs  in  (II)  to  engage  the  second  pre- 
molars may  be  attached  to  the  first  molar  band 
or  first  premolar  band  ;  if  the  former  be  a  clamp- 
band,  the  threaded  wire  of  the  clamping  mechan- 
ism will  serve  this  purpose.  The  lingual  wires  in 
(III),  when  they  extend  to  the  canine,  are  some- 
what long  and  liable  to  be  displaced  by  the 
stress  to  which  they  will  be  subjected ;  con- 
siderable strain  is  thrown  on  the  premolar  bands 
with  such  an  ai^phance.  In  both  cases  the 
length  of  buccal  wire  needs  a  support,  w  hich  may 


a 

Fig.  346. — Retention  of  lingual  movement  of  one 
incisor. 

Anchorage — Simple  reinforced. 

(a)  Before  treatment. 

(6)  After  treatment. 

The  tooth  that  was  in  labial  occlusion  is  banded,  and 
a  spm-,  soldered  to  the  lingual  surface  of  the  band, 
extends  to  one  adjacent  tooth  on  either  side.  This 
also  prevents  the  left  central  and  right  lateral 
closing  together  again. 

be  provided  by  a  notch  in  the  seam  of  a  band 
on  one  of  the  centrals. 

(See  Fig.  345.)  Another  method  of  retaining 
all  the  incisors  in  a  position  lingual  to  the 
original  is  to  band  the  canines,  or  any  teeth 
distal  to  them,  and  coimect  them  by  a  lingual  wire 
which  is  soldered  to  a  band  on  one  of  the  cen- 
trals.    From  this  band  a  wire  extends  on  each 


233 


side  to  engage  the  laliial  surfaces  of  all  the 
incisors  that  have  been  moved  lingually.  This 
is  especially  satisfactory  if  one  of  the  laterals 
has  not  shared  in  the  lingual  movement; 
but,  if  the  spur  wire  must  extend  over  two 
teeth,  there  is  less  danger  of  impairment  of 
the  appliance  on  account  of  the  comparatively 
slighter  stresses  of  mastication  compared  with 
those  experienced  in  other  situations. 

\\lien  only  one  or  t^^•o  teeth  have  to  be  held 
in  a  lingual  position,  a  band  (on  the  tooth  that 
was  misplaced)  ^\ith  a  lingual  \\ire  to  one  or 
two  of  the  approximal  teeth  is  sufficient  (see 
Figs.  346,  347) ;  or  two  bands  with  a  labial 
wire  may  be  employed  (see  Fig.  348,  a),  and  this 
plan  is  indicated  when  the  bite  would  be  dis- 
turbed by  lingual  appliances,  especially  if  the 
various  parts  are  separate  from  one  another,  as 
these  are  greater  in  bulk.  The  original  irregu- 
larity is  shown  at  Fig.  348,  A.  Fig.  348,  b  shows 
another  method  of  retaining  this  irregularity. 
Fig.  349  shows  how  the  retainer  in  Fig. 348,  a,  may 
be  constructed  of  three  separate  parts  ;  the  loop 
on  the  band  is  such  that  the  wire  may  be  just 
forced  into  it  and  held  so  that  it  will  not  slip  out  of 
its  own  accord,  but  can  be  removed  with  a  gentle 
pull.  These  loops  must  be  made  accurately, 
as  there  is  danger  of  damaging  the  appliance 
if  an  attempt  is  made  to  bend  them  much  after 


4,  6,  8,  39,  are  employed  with  the  addition  of 
a  buccal  ^^ire  to  engage  the  teeth  that  have 
been  moved  lingually.  The  wire  should  be 
attached  at  both  ends,  passing  from  the  lingual 


^ 


c::^ 


Fig.  347. — Three  methods  o£  retention  of  lingual  movement  of  one  premolar. 
Anchorage — Simple  in  (a)  and  (6)  ,■   Simple  reinforced  in  (c). 
A.  Original  abnormality. 

In  each  case  there  is  a  plain  band  on  the  tooth  that  was  misplaced.     To  the 
lingual  surface  of  the  band  is  soldered  in — 
(a)  a  lingual  spur  to  engage  the  adjacent  premolar; 
(6)  a  lingual  spur  to  engage  the  adjacent  canine ; 
(c)  a  lingual  spur  to  engage  the  adjacent  premolar  and  canine. 
A  fourth  method  would  be  to  band  the  canine  and  second  premolar  and  luiite 
these  two  bands  with  a  buccal  wire,  which  would  hold  the  first  premolar 
in  its  new  position. 


Fig.  348. — Retention  of  two  buccally  misplaced  central 

incisors. 
Anchorage — -Simple  reinforced. 
A.   Original  abnormality. 

(a)  The  centrals  retained  by  the  laterals,  which  are 

banded  and  miited  by  a  labial  wire. 
(6)  One  central  is  banded  and  has  a  labial  spur 
engaging  the  other  central.  A  Ungual  wire  engages 
all  four  incisors,  so  that  the  laterals  again  retain 
the  centrals.  This  form  has  the  advantage  of 
only  requiring  one  band. 

to  the  buccal  surface  where  two  teeth  ap- 
proximate. The  buccal  wires  should  not  include 
more  teeth  than  absolutely  necessary,  as  the 
longer  they  are  the  more  difficult  they  arc 
to  manipulate.  It  may  be  an  advantage  at 
times  to  make  the  buccal 
\\ire  in  two  or  three  sections, 
any  teeth  intervening  be- 
tween them  being  engaged 
by  an  extension.  Some 
o])erators  prefer  to  cast  w  ires 
of  this  nature  rather  than  to 
bend  them,  as  great  accuracy 
of  fit  may  be  obtained, 
tliough  it  should  not  be 
overlooked  that  for  the  pur- 
pose of  retaining  teeth  in 
position  it  is  not  necessary 
that  the  wire  be  carried  into 
the  approximal  spaces,  but 
only  be  in  contact  \\  itli  each 
tooth  at  one  point ;  as  regards 
cleanliness  the  latter  method 
is  the  more  desirable. 


they  are  in  situ.  The  thinner  the  wire  of  which 
they  are  made  the  less  chance  there  is  of  dam- 
aging the  band  or  its  attachments  ;  in  no  case 
should  it  be  greater  than  gauge  20  (B.  &  S.). 

10,  12,  14,  16,  and  41.     Removable  Appli- 
ances.—  Plates  such  as  those  described  for  2, 


C.  and  D.  Medial  and  Distal 
Movements. 
{</)   Of  the  Teeth. 
{b)  Of  the  Lower  Jaw. 
(a)  0/  the    Teelh.—Whcn 
all  the  teeth  have  erupted  it 
is  obvious  that  they  will  retain  one  another,  as 
their  approximal  contact  will  prevent  movement 
of  any  tooth  in  either  of  these  directions.     The 
maintenance  of  approximal  contact  is  realized 
by  the  retention  of  buccal  and  lingual  move- 
ment, which  has  just  been  dealt  with. 


234 


If  any  of  the  permanent  teeth  anterior  to  tlie 
first  permanent  molars  are  unerupted  and  are 
not  about  to  enipt,  though  space  exists  for  their 
reception  through  early  loss  of  their  deciduous 


Fio.  349. — A  retaining  appliance  identical  with  that 
shown  in  Fig.  348,  a,  except  that  its  three  parts 
are  separate. 

Anchorage — Simple  reinforced. 

On  one  lateral  band  there  is  a  tube  closed  at  one  end  ; 
on  the  other  there  is  a  loop  to  engage  the  buccal 
wire,  on  which  tliere  is  a  lug  to  engage  the  loop, 
and  so  prevent  the  wire  slipping  out  of  the  tube. 
The  small  additional  diagrams  show  the  arrange- 
ment of  the  loop  and  lug  in  relation  to  the  labial 
wire. 

predecessors,  means  must  be  employed  to  pre- 
serve that  space,  or  else  the  teeth  approximal 
to  it  will  encroach  on  it. 

21,  23,  25,  27,  and  42.  Fixed  Appliances. 
(See  Fig.  350.)     If  a  retaining  appliance  is  being 


Fig.  350. — Retention  of  buccal  movement  in  the  incisor 
and  premolar  regions. 

The  deciduous  canines  have  been  lost  and  the  permanent 
successors  have  not  yet  erupted.  On  one  side  the 
band  and  a  spur  retain  the  space ;  on  the  other 
side  two  spurs  are  used. 

used  for  any  other  purpose,  all  that  is  neces.sary 
is  to  solder  short  spurs  on  the  buccal  or  lingual 
retaining  wire,  ^^•hicll  shall  be  in  contact  %\ith 
the  teeth  on  their  approximal  surfaces  contigu- 
ous with  the  space. 

(See  Fig.  351.)  If  no  other  retention  is  needed, 
the  teeth  on  each  side  of  the  space  are  to  be 
banded  and  comiected  by  a  buccal  or  lingual 
wire,  or  botli ;  in  this  way  the  space  cannot 
be  encroached  on,  and  the  reason  for  placing  the 
wire  buccally  or  lingually  is  that  the  eruption 
of  the  tooth  may  not  be  interfered  ^\'ith. 

(See  Fig.  352!)  Wlien  one  of  the  teeth  next 
the  space  is  a  deciduous  one,  that  tooth  need  not 
be   banded ;    instead,  a  half-round  wire    clasp 


may  be  fitted  near  the  neck  of  the  tooth  and 
the  buccal  and  lingual  wires  soldered  to  it.  A 
cleat  should  extend  from  this  clasji  to  engage 
the  occlusal  surface  of  the  tooth  so  that  the 
stress  of  mastication  shall  not  displace  it. 
If  a  space  is  to  be  retained,  and  the  successional 
tooth  is  not  ready  to  erupt  into  it,  it  may  be 
preserved  as  already  described,  or  even  increased 
by  means  of  the  accessory  appliance  shown  in 
Fig.  299.  Both  teeth  are  banded  ;  to  one  apiece 
of  threaded  wire  as  long  as  possible  is  soldered. 
On  this  wire  there  is  a  nut,  which  is  also  to  be 
as  long  as  possible.  The  turning  of  this  nut 
against  the  tooth  will  enlarge  the  space ;    this 


Fio.  351. — Retention  of  space  for  unerupted  canine. 
Plain  bands  on   the  lateral  and  first  premolar  with  a 
lingual  wire  joining  them. 

appliance  ^lill  also  retain  the  space.  If  a  ledge 
with  a  flat  surface  is  soldered  horizontally  to 
the  band,  and  near  tlie  cervical  edge  of  the  sur- 
face against  which  the  nut  impinges,  it  will 
prevent  the  turning  of  the  nut  except  by  a 
wrench,  and  also  prevent  its  displacement  by 
mastication. 

22,  24,  26,  28,  and  43.  Removable  Appli- 
ances.— Spurs  are  attached  to  the  appliance 
similar  to  those  described  under  fixed  appliances, 
and  designed  to  serve  the  same  purpose  (see  Figs. 


PQ 


Fig.  352. — Retention  of  space  for  unerupted  canine  and 
first  premolar. 

On  the  lateral  there  is  a  plain  band ;  on  the  second 
deciduous  molar  tliere  is  a  half-round  wire  clasp 
with  extension  to  the  occlusal  siu'face.  (Other 
views  of  this  are  shown  at  (a)  and  (b).)  Buccal  and 
lingual  wires  unite  the  band  and  clasp. 

342,  361).  The  space  should  not  be  retained 
by  means  of  a  block  of  vulcanite,  as  this  is 
likely  to  interfere  with  the  eruption  of  the 
permanent  tooth,  unless  it  is  not  expected  for  a 


235 


protracted  period,  when  such  a  block  may  be 
used  as  it  will  provide  a  substitute  for  the  lost 
tooth,  and  so  permit  the  opposing;  tooth  to  be 
useful  for  masticating  purposes  which  is  bene- 
ficial and  desirable.  If  it  has  been  necessary 
to  remove  a  deciduous  tooth  before  its  successor 
is  ready  to  take  its  place  the  space  should  always 
be  maintained  in  one  of  the  ways  just  described. 

{h)  Of  the  Lower  Jaw. 

19  and  29.  Fixed  Appliances. — Upper  and 
lower  retaining  appliances  must  be  used,  which 
are  supported  by  at  least  four  teeth  by  means  of 
bands,  the  two  first  permanent  molars  and  the 
two  permanent  upper  canines  always  being  the 
selected  teeth  when  they  are  erupted ;  when 
unerupted,  the  teeth  that  can  be  most  suitably 
substituted  are  used. 


impossible  (see  Fig.  354) ;  the  strain  on  these, 
however  strongly  they  might  be  made,  and  on 
the  teeth,  frequently  appeared  to   be  so  great 


3 
Fig.  353. — Retention  of  lower  jaw  medially. 

Upper  appliances  :  Bands  on  molars  and  canines  with 
buccal  and  lingual  bows  or  a  combination  of  these 
as  in  Fig.  314.  In  this  diagram  a  complete  buccal 
wire  is  shown  soldered  to  the  molar  band  and  held 
in  relation  with  the  canine  band  by  means  of  a  wire 
loop  (1).  To  the  latter  band  a  hook  (2)  is  soldered 
for  the  attacliment  of  the  rubber  band. 

Lower  appliances  :  Bands  on  molars  and  canines  with 
complete  lingual  wire  on  the  principle  of  that  in 
Fig.  356.  On  the  molar  band  is  a  hook  (3)  for  the 
other  attaclunent  of  the  rubber  band. 

Bands,  clamp  or  plain,  with  buccal  hooks  for 
rubber  bands  are  cemented  to  these  particular 
teeth ;  they  are  directed  forwards  in  the  case 
of  the  canines  and  distally  in  the  case  of  the 
molars.  Rubber  bands  unite  the  molar  and 
canine  bands  of  the  opposite  jaws  on  one  or 
both  sides  according  as  one  or  both  sides  are  to 
be  retained.  If  the  lo\\er  jaw  has  to  be  retained 
in  a  medial  position  the  rubber  band  is  stretched 
from  the  upper  canine  to  the  lower  molar, 
as  in  Fig.  353  ;  if  it  is  to  be  retained  in  a  distal 
position  then  it  is  stretched  from  the  lower 
canine  to  the  upper  molar.  The  tension  they 
exert  is  to  be  very  light — only  just  sufficient 
to  hold  the  lower  jaw  in  its  new  position  and 
not  such  as  to  move  it  still  further. 

The  method  just  described  is  undoubtedly  the 
best  for  the  required  purpose.  Formerly  spurs 
were  soldered  vertically  to  the  buccal  surfaces  of 
the  upper  and  lower  molar  bands,  so  as  to  make 
closure   of  the    jaws   in   an  incorrect  position 


Fig.  354. — -Retention  of  lower  jaw  medially. 
Clamp-bands  on  upper  and  lower  molars ;  to  the  buccal 
surface  of  these  bands  spurs,  of  strong  square  wire, 
are  very  securely  soldered,  and  are  bevelled  to 
■  compel  the  jaws  to  close  in  normal  relation  to  one 
another.  The  arrangement  of  the  spurs  is  reversed 
to  retain  the  lower  ja%T  in  a  distal  position. 

that   the  appliance   gave   way  or    the    molars 
tilted. 

20.  Removable  Appliances. — These  are  only 
to  be  regarded  as  satisfactory  when  the  slightest 
stimulus  is  sufficient  to  keep  the  lower  jaw  in  its 
forward  position.  For  this  purpose  a  vulcanite 
plate  is  made  with  a  thickened  portion  behind 
the  upper  incisors,  which  slopes  from  below  up- 
wards and  forwards  and  serves  as  an  inclined 
plane  (see  Fig.  355).  It  is  extended  so  far  back 
that  the  lower  incisors  cannot   avoid    striking 


Fig.  355. — Retention  of  lower  jaw  medially. 
Removable  appliance. 

1.  Upper  vulcanite  plate  in  section. 

2.  Thickened  portion  of   plate   behind  upper  incisors 

with  inclined  surface  to  bring  the  lower  jaw  into 
correct  position  when  the  jaws  close;  tliis  also 
serves  to  make  the  amount  of  overbite  correct. 

it,  and  when  they  do  so  the  lower  jaw  is  com- 
pelled to  slide  forward  into  normal  relation 
with  the  upper  jaw. 

E.  Depression 

30,  32,  44,  and  46.  Fixkd  Appliances. — (See 
Fig.  356  )  The  teeth  that  have  been  depressed 
must  be  banded,  and  have  spurs  soldered  on 


236 


their  buccal  or  lingual  surfaces  at  right  angles 
to  the  long  axis.  A  buccal  or  lingual  wire,  as 
the  case  may  be,  is  then  made  to  engage  these 
spurs  on  their  occlusal  aspect ;  it  is  attached  to 
two  or  more  bands  on  teeth  that  have  not  been 
depressed  ;  these  will  be  the  molars  or  premolars 


Fig.  356.— Retention  of  buccal  movement  of  all  the  teeth  and  depression 

of  two  incisors. 
Anchorage — Reinforced  reciprocal. 
1'.  Lintrual  retaining  wii-e,  holding  all  the  teeth  in  their  new  buccal  positions 

_tlie  second  right  and  first  left  premolar  and  the  first  left  molar. 
2'.  Plain  bands  to  which  (!')  is  jomed  by  solder  or  otherwise. 
3'.  Plain  bands  on  the  left  central  and  lateral. 
4'.   Spurs  on  lingual  surface  of  bands,  (3'),  directed  lingually  and  engaged 

by  (1')    which  thus  holds  these  teeth  in  their  depressed  positions, 
(a)  Cross-section  of  the  left  central,  with  plain  band,  spiu-,  and  lingual 

wire  in  position. 

in  most  cases,  as  it  is  usually  the  incisors  that 
are  moved  in  this  direction. 

(See  Fig.  357.)  When  a  buccal  wire  is  the  basis 
of  the  appliance  it  may  have  extensions  soldered 
to  it  to  engage  the  incisal  edges  of  the  teeth 
that  have  been    depressed,  and    so  avoid  the 


Both  depression  and  elongation  may  be 
retained  by  soldering  the  buccal  or  lingual  wire 
direct  to  the  bands  on  the  teeth  that  have  been 
moved,  as  well  as  by  allowing  these  wires  to 
engage  spurs  on  the  bands. 

31,  33,  45,  and  47.  Removable  Appliances. 
The  same  principle  is  followed  as 
with  fixed  appliances,  except 
that  the  buccal  or  lingual  wire 
is  attached  to  the  plate,  and 
this  wire  may  be  given  a  little 
spring  so  as  to  exert  a  slight 
force  in  the  desired  direction. 
The  appliance  must  be  held 
firmly  by  clasps  on  the  molars 
or  premolars  or  both. 

F.  Elongation 

34,  36,  48,  and  50.  Fixed 
Appliances.  (See  Fig.  358.) 
This  movement  is  retained  in 
the  reverse  mamier  to  that  just 
described  for  Depression.  Wlien 
incisors  have  to  be  retained  the 
buccal  wire  engages  the  gingival 
aspect  of  spurs  on  bands  on 
these  teeth. 

If  the  molar  series  have  to 
be  retained  by  means  of  the 
six  anterior  teeth,  the  canines 
should  certainly  be  two  of  those 
banded.  A  removable  appliance 
is  better  adapted  for  retaining 
the  posterior  teeth  in  this  position. 

If  all  the  teeth  in  one  or  both  jaws  have  to  be 
retained  in  an  elongated  position,  the  appUance 
described  for  retaining  incisors  should  be  em- 
ployed, and  spurs  soldered  to  the   molar   and 


Fig.  357. — Retention  of  lingual  movement  and  of 
depression  of  the  upper  incisors. 

Anchorage — Reinforced  simple. 

The  buccal  wire  retains  the  lingual  movement;  from 
this  wire  a  spur  goes  to  the  incisal  edge  of  each 
tooth  that  has  been  depressed,  and  is  bent  over  to 
engage  this  edge  as  shown  at  (a).  These  spurs 
retam  the  teeth  depressed  in  their  sockets. 

necessity  of  banding  the  incisors ;  care  must 
be  taken  that  these  extensions  do  not  interfere 
with  the  bite.  Having  regard  to  the  question 
of  overbite,  it  may  be  said  that  this  method  is 
better  suited  for  upper  mcisors,  and  the  former 
one  for  lower  incisors,  unless  the  wire  and  spurs 
are  placed  buccally,  when  it  may  also  be  used 
in  the  upper  jaw. 


Fig.  358. — Retention  of  elongation  of  the  incisors. 
Anchorage — Reinforced  simple. 

1.  Bands  on  the  teeth  to  be  retained  in  an  elongated 

position. 

2.  Spurs  on  the  bands,  on  the  gingival  aspect  of  which 

the  buccal  wire  is  in  contact. 

3.  Buccal  wire  engaging  the  gingival  aspect  of  the  spurs. 
(A  lingual  wire  with  spurs  on  the  lingual  surfaces  of 

■  the   bands   may   be  used  instead — this  method  is 
especially  applicable  to  lo%ver  incisors.) 
(a)  Shows  one  of  the  banded  incisors  in  cross-section. 

premolar  bands,  and  to  the  buccal  wire  in  the 
incisal  region,  to  be  used  for  the  attachment  of 
inter-maxillary  rubber  bands,  the  force  exerted 
being  only  sufficient  to  hold  the  teeth  witliout 
further  moving  them;    in  this  way  the  teeth 


237 


in  one  jaw  that  have  not  been  moved  can  be 
used  to  retain  those  in  the  opposite  jaw.  The 
principle  of  the  appHcation  of  this  method  is 
shown  in  Fig.  316,  except  that  the  rubber  band 
should  be  directly  vertical. 

Appliances  used  to  bring  about  movement 
may  also  be  used  as  retainers,  by  converting 
the  active  force  into  a  passive  one. 

35,  37,  49,  and  51.  Removable  Appliances. 
An  upper  vrilcanite  biting  plate  is  best 
adapted  to  retain  tlie  premolars  and  molars 
in  their  new  positions,  the  thickened  poition 
behind  the  incisors  being  such  that  when  the 
lower  incisors  occlude  with  it  the  molar  series 
will  also  be  in  occlusion ;  ^\'ith  such  a  plate  the 
teeth  will  not  be  forced  back  into  their  sockets. 
This  retains  both  upper  and  lower  molars. 

49  and  51.  To  retain  the  incisors  a  buccal 
wdre  is  arranged  on  the  plate  to  engage  spurs 
on  bands  on  these  teeth  in  just  the  same  way  as 
when  fixed  appliances  are  used.  Such  a  plate 
may  be  used  in  the  upper  or  lower  jaw. 

G.  Rotation 

This  movement  is  best  retained  by  fixed 
appliances. 


tlmt 


that  has  been  ])ullcd  outwards,  and  the  other 
to  hold  that  which  has  been  pulled  inwards. 

(See  Fig.  3(50.)     If  one  comer  has  remained 
stationary  it  « ill  not  be  essential  to  retain  it. 


Fig.  359.  —  Upper  lateral  in  torso-occliision ;  both 
comers  of  the  tooth  were  misplaced ;  two  teeth 
are  used  to  retain  it  in  its  new  position. 

Anchorage — Reinforced  simple. 

A.  Before  treatment. 

B.  After  treatment. 

(a)  Plain  band  on  the  rotated  tooth. 

(6)  Labial   spur    to    hold   out   the   corner 

turned  in. 
(c)  Lingual    spur   to    hold    in    the   corner    that    wa.s 

turned  out. 

52.  Fixed  Appliances. — (See  Fig.  359.)  A 
band  is  made  for  the  rotated  tooth  and  spurs 
are  soldered  to  it,  one  labially  and  the  other 
lingually- — the  former  to  hold  labially  the  comer 


c^:^]:^, 


Fig.  360. — Retention.     The  simplest  anchorage. 
Lower  canine  in  torso-occlusion,  the  distal  comer  only 
being  misplaced, 
(a)  Before  treatment. 

(6)  After  treatment.  The  retainer  consists  of  a  plain 
band  on  the  canine  with  buccal  spm:  directed 
distally  to  rest  on  the  buccal  siu-face  of  the 
premolar. 
One  tooth  is  used  to  retain  one  other  tooth,  which  has 
a  greater  resistance  value,  but  it  is  unlikely  that 
the  premolar  will  be  displaced  lingually  by  the 
tendency  of  the  distal  comer  of  the  premolar  to 
rotate  inwards  again. 

Contiguous  teeth  may  be  retained  on  the  same 
principle,  or  by  banding  each  tooth  and  rigidly 
uniting  the  bands.  The  former  is  preferable 
as  it  permits  of  sUght  individual  adjusting 
movements. 

53.  Removable  Appliances. — These  cannot 
always  be  arranged,  so  as  to  be  efficient,  but  if 
there  is  a  space  approximal  to  the  rotated  tooth 
they  may  be  satisfactorily  employed  as  long 
as  the  patient  wears  the  appliance  constantly. 

(See  Fig.  361.)  Wire  extensions  from  the 
plate  must  engage  the  two  comers  of  the  tooth 
so  as  to  oppose  their  tendency  to  relapse  into 
their  former  positions.  The  wire  extensions 
must  be  short  and  rigid,  or  else  there  will  be 
great  liability  for  the  retention  to  be  insufficient. 
Vulcanite  may  be  arranged  to  impinge  hard  on 
the  lingual  comer  that  has  been  moved  buccally. 

(See  Fig.  362.)  If  there  is  no  space  approximal 
to  the  rotated  tooth,  a  wire  extension  from  the 
plate  may  be  brought  over  the  incisal  edge 
of  the  tooth,  at  the  comer  which  has  been  pulled 
in,  the  plate  holding  out  the  other  comer. 
This  can  only  be  used  where  the  bite  permits 
of  it  and  the  tooth  is  of  such  a  shape  that  it 
will  be  efficient.  A  rotated  canine  could  not 
be  retained  in  this  way. 

Retaining  appliances  may  be  used  to  a  slight 


238 


extent  to  move  teeth.     There  are  several  ways 
in  which  this  may  be  done. 

(1)  By  stretching  a  wire,  in  that  part  of  its 
course  ^^•hich  is  intermediate  between  two  fixed 
points,  with  a  pair  of  pHers  specially  designed 
by  Angle  for  the  purpose.    This  plan  is  specially 


Fig.   361. — Vulcanite  plate  and  attaclunent  to  retain 

a  rotated  lateral  incisor, 
(o)  Shows  the  case  before  treatment. 
1'.  Wire  to  hold  the  lateral  medially  and  preserve  the 

space  for  the  canine. 
2'.  Vulcanite  plate  hard  against  the  lingual  surface  of 

the  lateral  to  hold  it  buccally. 
3'.  Prolongation  of    (!')  to  hold  the  medial  comer  of 

the  lateral  lingually. 
4'.   Spur  to  hold  the  premolar  distally  to  prevent  its 

encroachment  on  the  space  for  the  canine. 

indicated  wlien  the  deciduous  canines  are  still 
in  position  and  the  width  between  them  is 
too  narrow — an  almost  universal  abnormality  in 
every  type  of  irregularity.  There  are  numerous 
other  occasions  wlien  it  may  be  used. 

(2)  Rubber  between  the  retaining  wire  and  the 
tooth  will  bring  about  movement  of  the  latter ; 
when  this  is  sufficient  the  rubber  is  discarded 
and  the  wire  bent  to  retain  the  tooth  in  its  new 
position.  This  method  is  especially  ajjplicable 
when  the  wire  engaging  the  tootli  to  be  moved 
is  attached  at  one  end  only,  as  in  the  case  of 
rotated  teeth,  because  it  can,  without  difficulty, 
be  rebent  while  in  the  mouth  to  engage  the  tooth. 
If  the  movement  is  to  be  considerable,  rubber 
may  be  used  and  the  wire  bent  alternately,  so 
that  the  distance  bet\\ecn  tooth  and  wire  may 
not  become  so  great  as  to  render  the  rubber 
inefficient. 

(3)  The  retainer  shown  in  Fig.  341  may  be 
used  to  increase  or  decrease  the  length  of  the 
arch  by  means  of  the  nut  rumiing  on  the  threaded 
lingual  wire,  a\  hich  engages  the  medial  end  of 
tlie  short  lingual  tube.  This  arrangement  may 
be  employed  on  one  or  both  sides.  When  on 
both  sides  one  of  the  bands  with  tube  attached 


would  have  to  be  fixed  in  position  last  of  all,  as 
described  on  p.  230. 

(4)  Wlien  retainers  are  used  with  detached 
lingual  or  buccal  \vire  this  may  be  sprung, 
especially  if  made  of  platinized  gold,  to  increase 
or  decrease  the  width  of  the  arch  in  the  molar 
and  premolar  region. 

(5)  Wlien  a  tooth  that  should  be  in  contact 
w  ith  the  retaining  wire  is  away  from  it,  a  ligature 
passing  round  the  tooth  and  wire  may  be  used 
to  bring  it  to  its  proper  position  as  long  as  the 
necessary  space  for  it  exists. 

(6)  The  Angle  working  retainer  is  one  designed 
to  hold  teeth  bodily  forward  (in  contradistinc- 
tion from  just  holding  them  at  one  point,  as  is 
the  case  when  a  single  wire  is  used  to  retain 
teeth),  or  even  move  the  root  apices  a  little.  It 
is  especially  applicable  to  the  upper  incisors. 
To  each  tooth  to  be  moved  or  held  forward  a 
band  is  fitted,  to  which  a  vertical  labial  tube 
of  very  small  diameter  is  soldered.  A  labial 
w  ire  is  bent  to  engage  these  teeth  (being  attached 
by  any  suitable  method  already  described),  and 
to  it  short  lengths  of  wire,  of  such  a  gauge  as  to 
fit  accurately  the  tubes  on  the  bands,  are  sol- 
dered at  right  angles  to  the  length  of  the  wire, 
and  parallel  with  the  long  axes  of  the  teeth, 
and  in  such  positions  that  they  will  enter  the 
tubes  exactly  and  from  their  incisal  aspects. 
These  tubes  and  wires  should  be  from  J^  to  J  inch 
in  length,  and  by  bending  the  latter  outwards  at 


Fia.   362. — Retention  of  an  incisor  that  was  in  torso- 
occlusion  by  a  removable  appliance. 

r.  Vulcanite  plate. 

2'.   Spur  engaging  the  incisal  edge  and  medial  corner  of 

the  lateral  to  hold  it  in.     The  plate  is  made  to  fit 

tightly  against  the  lingual  surface  of  the   opposite 

corner  to  hold  it  out  (labially). 
(a)  Cross-section  ot  the  tooth  that  was  in  torso-occlusion, 

with  apparatus  m  position. 

the  gingival  end  the  apex  of  the  tooth  may  be 
carried  forward  should  this  be  desired. 

Angle's  Recent  Modiflcation  of  the  Wire  Bow 

Angle  (1)  and  Lowe  Young  (13)  describe  a 
method  of  moving  the  incisors  without  using 
ligatures.     The  principle  emjiloyed  is  similar  to 


239 


that  described  under  retention  for  retaining  teeth 
while  yet  permitting  some  movement  to  he  ob- 
tained. The  appHance,  a  bow,  is 
attached  as  usual  through  the 
medium  of  clamp-bands  on  the  mo 
lars.  All  four  incisors  are  banded 
to  the  labial  surfaces  of  these  bands 
vertical  tubes  are  attached  ;  to  the 
bow  vertical  pins  are  soldered  to 
engage  these  tubes.  Root  move- 
ment, in  any  direction,  is  obtained 
by  suitably  bending  the  vertical 
spurs ;  movement  of  the  crowns 
by  means  of  the  nuts  engaging 
the  buccal  tubes  on  the  molar 
bands,  and  by  bending  the  bow 
with  pliers.  The  thickness  of  tiie 
bow  is  only  •77  of  a  millimetre. 
AppUances  and  methods  are  de- 
scribed to  facilitate  the  construction 
of  these  bows  and  accessories. 

THE    TREATMENT    OF    PAR- 
TICULAR   CASES 

Case  1.     (Hakold  Chapman.) 

The  casts  are  those  of  a  little 
girl,  aet.  7.  The  dental  arches,  as 
represented  by  the  first  permanent 
molars  and  deciduous  canines,  are 
in  normal  relation  to  one  another, 
but  both  are  much  too  narrow  to 


permanent  centrals  are  erupted,  and  the  corre- 
sponding laterals  are  about  to  erupt,  in  lingual 


Fi< 


:i(i4. — Ciusi- 


Fig.  363. — Case   1.      Before  treatment. 


permit  the  permanent  teetii  to  a.s.sume  correct 
positions   wlien   they   erupt.     The    two    lower 


1.      After  treatment. 

and  torso  -occlusion.  In  the  upper 
jaw  the  permanent  centrals  have 
already  erupted,  but  the  laterals 
are  not  as  far  advanced  as  in  the 
opposite  jaw;  it  is  evident  that 
the  space  that  is  waiting  for  them 
is  not  nearly  sufficient. 

The  patient  could  not  be  seen 
frequently,  so  removable  appli- 
ances had  to  be  used.  Fig.  363 
show  s  models  of  the  case  :  the 
light  and  left  sides  in  occlusion 
i  nd  the  occlu.sal  view  of  the 
upper  and  lower  teeth;  the  pro- 
minent featiues  are  marked  nar- 
row lug  and  shortening  of  both 
dental  arches  and  very  consider- 
able rotation  of  the  rigiit  lower 
central  ;  the  overbite  is  also 
greater  than  normal.  The  ex- 
])ansion  of  the  upper  jaw  was 
brought  about  entirely  by  means 
of  a  Badcock  plate.  The  lover 
jaw,  however,  was  not  wide 
enough  for  this  particular  expand- 
ing a])pliance,  and  so  the  smaller 
size  Highton  device  was  used. 
The  following  extracts  from  tiie  writer's 
case-book  indicate  the  course  of  treatment. 


240 


1911. 
Aug.  30. 

Sept.  26. 
Sept.  29. 


Lower  Highton  expansion  plate  put 

in.     Clasps  on  6  |  c.6. 
Highton  plate  expanded  to   fullest 

extent. 
Re-made  Highton  plate  fitted. 


their  respective  teeth,  rubber  waa 
inserted  in  order  to  rotate  1  |  . 

Oct.  20.  1  I  having  rotated,  the  spurs  were 
bent  to  come  in  contact  again 
with  their  respective  teeth,  so 
that  the  use  of  rubber  for  obtaining 
rotation  might  be  continued. 

Nov.  6.  A  new  band  was  cemented  to  1  |  ,  to 
continue  tlie  rotation  in  the  same 
way  as  before.  

Dec.  19.       The    spurs    of    band    on    1  |    were 
bent  to    retain   the  tooth    in   its 
present  position. 
1913. 

Feb.  22.      The  case  is  being  retained  by  upper 
and  lower  vidcanite  plates  and  a 
band     on    1  |  ,  with  buccal    and 
lingual  spurs. 
Total  visits  to  date,  27. 
Results  of  treatment  are  shown  hi  Fig.  364. 

Case  2.     (Geoege  Northcroft.) 
ThVs  is  a  case  in  which  the  antero-posterior 
relations  of  the  jaws  are  normal,  but  they  are 
-Jbo^h  too  short  and  too  narrow ;    the  condition 

// 
/ 


Fig.  365. — Case  2.      Before  treatment. 

Oct.  12.       New   lower   Highton   plate   put   in. 

(Device  on  former  one  broken.) 
Nov.  30.       Highton  plate,  having  been  re-made, 

put  in ;  also  upper  Badcock  plate 

put  in. 


1912. 
Jan.  23. 


April  29. 


Oct.  2. 


The  lo\\er  jaw  having  expanded 
considerably,  tlie  Highton  plate 
was  rei^laced  by  a  Badcock  plate. 

Upper  and  lo\\cr  vulcanite  retention 
plates  put  in.  Springs  were  fixed 
on  the  lower  plate  to  move  c.2 1 2.c 
buccally. 

Iridio-platinum  band   cemented   on 

I  I  ,  with  buccal  spur  to  engage 

I  1.2,  and  lingual  spur  to  engage 

2^1       Batween    these    spurs    and 


Fig.  366. — Case  2.     After  treatment. 

is  complicated  by  the  fonvard  movement  of 
the  first  right  upper  molar,  the  result  of  loss 
of  the  second  right  upper  deciduous  molar 
before  the  successional  tooth  was  ready  to 
replace  it.     (See  Fig.  365.) 


241 


Fio.  367. — Case  3.     Before  treatment. 


Fro.  308. — Case  3.     After  treatment. 


Fig.  369. — Case  4.      Before  treatment. 


Kio.  3jO. — C'iiso  4.     After  treatment. 


242 


Fig.  371. — Case  5.     Before  treatment. 
Open  bit©.     The  only  teeth  that  occlude  are  the  second  left  molars.     On  the 
right    side    the    second    molars    have    moved    forward,    especially    the 
upper. 

Fixed  aj)pliances  were  used  in  the 
customary  manner ;  inter-maxillary 
force  was  not  employed.  Treatment 
was  primarily  directed  to  moving 
the  first  right  upper  molar  distally 
until  it  occluded  normally  with  the 
corresponding  lower  tooth  ;  for  this 
purpose  all  the  anterior  teeth  were 
employed  as  anchorage  in  the  wny 
described  on  pp.  191  and  205. 
When  this  movement  was  nearly 
complete,  expansion  of  the  upper 
and  lower  jaws  and  for\\ard  move- 
ment of  the  incisors  was  undertaken, 
the  four  permanent  molars  being 
used  as  anchorage.  This  movement 
was  already  started  in  the  upper 
jaw,  because  the  ancliorage  afforded 
by  the  incisors  for  movement  of 
the  upper  molar  was  not  sufficient 
to  avoid  some  slight  displacement, 
which  in  this  case  was  a  displace- 
ment desired. 

The  total  number  of  visits  required 
for   the   treatment   was    36 ;    10    of 


these  were  on  account  of 
retention,  which  usually 
only  required  to  be  exam- 
ined .  Treatment  was  begun 
on  the  5th  of  October,  1907, 
the  patient  being  lOf  years 
old.  The  retention  appli- 
ances were  put  m  on  the 
7th  of  January,  1908,  and 
continued  till  December, 
1908. 

Simple  vulcanite  plates 
were  used  for  retention.    rA 

Results  of  treatment  are 
shown  in  Fig.  366. 

Case  3.  (Geo.  Northcroft.) 

In  this  case  the  lower 
jaw  is  in  post-normal  rela- 
tion with  the  upper,  which 
is  too  short  and  too  narrow, 
so  that  the  spaces  for  the 
erupting  canines  are  too 
small ;  in  the  lower  jaw  all 
the  teeth  are  in  good  align- 
ment. In  order  to  obtain 
the  best  aesthetic  results, 
the  treatment  should  be 
with  the  object  of  enlarging 
the  spaces  between  the 
laterals  and  first  premolars 
by  expanding  the  molar 
series  and  moving  the  in- 
cisors forward  ;  at  the  same 


Fio.  372. — Case  5.     After  treatment. 

Extraction  of  the  first  left  molars  has  allowed  forward  movement  of  the 

second  molars,  and  the  bite  has  closed,  so  that  the  right  second 

molars  now  meet. 
The  left  upper  premolars  require  backward  movement,  and  the  upper 

incisors  can  then  be  drawn  back  into  normal  occlusion  with  the 

lowar. 


243 


time  the  lower  jaw  should  be  moved  forward 
by  inter-maxillary  force,  so  as  to  bring  it  into 
normal  antero-pos- 
terior  relation  with 
the  upper  teeth .  To 
effect  this,  very 
slight  movement,  if 
any,  of  the  lower 
teeth  would  be  re- 
quired. This  treat- 
ment was  decided  on, 
but  had  to  be  aban- 
doned as  the  patient 
developed  scarlet 
fever.  The  mode 
of  treatment  was 
reconsidered,  and 
it  was  thought  that 
the  simplest  method 
would  now  be  desir- 
able. This  case  is  one 
that  is  tjT3ical  of  the 
class  discussed  on 
p.  127,  for  which  ex- 
traction of  the  two 
upper       premolars 


was  accordingly  done  in'October,  1901,  when  the 
patient  was  aged  eleven.  Fig.  3G7  shows  the  upper 


A  B 

Fio.  373. — Photograplis  of  patient  shown  in  Figs.   371   and  372. 

A.  Before  treatment. 

B.  After  treatment. 
In  both  the  teetli  occlude.     Note  the  diminished  depth  of  the  dento-facial  area  after 

treatment. 

and  lower  teeth  in  occlusion, 
and  the  occlusal  view  of  the 
upper  teeth,  before  treat- 
ment. Fig.  368  shows  the 
same  views  six  years  after 
treatment.  In  both  illus- 
trations the  same  model  of 
the  lower  jaw  is  used.  It 
will  be  noticed  that  the  upper 
incisors  have  moved  lingu- 
ally,  through  lip  pressure, 
and  the  absence  of  any 
counteracting  resistance  to 
this,  tiie  result  of  the  space 
behind  the  erupting  canines. 
It  is  highly  probable  that 
liad  the  upper  molar  series 
been  u.sed  to  move  back  the 
incisors,  the  former  teeth 
would,  to  some  extent,  in  all 
probability  have  moved  for- 
ward, a  nn)vement  which 
must  be  avoided  in  all  cases 
of  this  nature. 


Case  4.   (Geo.  XoRTHCROFT.) 

Fig.  369  sho\\s  the  case 
when  the  patient  was  ten 
years  old.  The  lower  jaw  is 
seen  to  be  in  jjost -normal 
relation  with  tiie  upper.  The 
upper  dental  arch  is  too 
narrow,  and  the  incisors 
have  the  appearance  of  protruding,  though,  as 
is    so    frequently   the   case    in   irregularities  of 


Fio.  374. — Case  li.      lietoiv  tivaUuent. 
Postplacement  of    upper  incisors   (Ungual  occkision)    and  secondary  inferior 
protrusion. 

gives  an  excellent  occlusion  of  tlie  lower  teeth, 
and  entirely  avoids  mechanical  treatment.    Tliis 


244 


this  type,  it  is  not  so,  or  only  very  slightly; 
the  effect  bein"  produced  by  the  pnst-normal 


Photographs    of    patient    before    and 
treatment  are  shown  in  Fig.  373. 


after 


Case  6.     Aet.  11.     (Norman  G.  Bennett.) 


1912. 
June  3. 

June  17. 
June  17  to 
Oct  24. 


Oct  28  to 
Nov.  28. 
Dec.  30. 

1913. 
March  31. 


Fig.  375. — Portrait  of  case  shown  in  Fig.  374. 

position  of  the  lower  jaw  rather  than 
by  the  anterior  position  of  the  upper 
teeth.  The  overbite  is  also  seen  to 
be  excessive.  This  case  was  treated 
by  fi.xed  appliances ;  clamp-bands 
being  attached  to  tlie  first  molars  for 
supporting  the  wire  bows,  in  con- 
junction with  which  inter-maxillary 
force  was  employed.  The  upper 
dental  arch  required  greater  expan- 
sion than  the  lower.  The  amount  of 
overbite  was  reduced  by  the  forward 
movement  of  the  lower  jaw  establish- 
ing a  new  occlusal  level,  as  it  were. 
The  movements  of  the  teeth  are  all 
as  have  been  described  in  the  various 
paragraphs,  and  it  would  only  be 
repetition  to  describe  these  again. 

Results  of  treatment  are  .shown  in 
Fig.  370. 

Cases.  Aet.  13.   (Norman  G. Bennett.) 

1913. 

March  3.       Impressions  for  first  casts 
(see  Fig.  371)  and  photo- 
graphs   taken ;    extrac- 
tion of  first  left  molars. 
March  17  A 

31,  and    Conservative  treatment. 
April  7.     j 

April  14.       Impressions     for     second 
casts  (see  Fig.  372)  and 
photographs.     The  pre" 
molars    on    the    left    and    the 
upper  centrals  have  deviated  to 
the  left. 


Impressions  and  photograph  (see 
Fig.  375). 

Second  impressions  (see  Fig.  374). 

C;lamp-bands  with  buccal  tubes 
fitted  and  cemented  to  upper 
molars  ;  upper  bow  adjusted  and 
ligatures  used  to  bring  the 
incisors  forward  over  the  cor- 
responding lower  teeth. 

Vulcanite  denture  for  lower  jaw 
pending  eruption  of  more  teeth. 

Upper  bow  removed. 

Impressions  (see  Fig.  376).     Plate 
eased  over-erupting  4  |  4. 


Photograph  of  patient  after  treatment  shown 
in  Fig.  377. 


Fig.  370. — dis^c  fi.     After  treatment. 

Case  7.     (Harold  Chapman.)     (See  Fig.  378.) 

Upper  Jaw. — This  needed  the  more  widening, 

so  treatment  was  started  on  it.    A  Badcock  plate 


245 


was  used  for  this  purpose  with  the  screw  opposite 
the  second  deciduous  molars.  A  labial  \\  ire  of 
platinized  gold  was  arranged  to  come  from  the 
palatal  surface  of  the  plate  bet\\een  the  canines 
and  laterals,  and  was  bent  to  touch  the  labial 
surfaces  of  the  centrals  and  laterals.  This 
arrangement  of  wire  pulls  back  the  incist)rs  as 
expansion  progresses,  but  it  may  be  entirely 
under  control  by  making  a  U-loop  in  the  wire 
on  each  side  just  after  it  comes  on  to  the  buccal 
surface  of  the  teeth.  This  wire  is  to  rest  at 
the  junction  of  the  middle  and  incisal  thirds  of 
the  centrals.  To  increase  the  pressure  that 
it  exerts  on  the  incisors  beyond  ^\  hat  results 
from  the  expansion  of  the  plate,  the  U -loops 
are  pinched  together.  In  order  that  the  wire 
shall  keep  in  position  on  the  centrals,  one  of 
these  should  have  a  plain  band  cemented  to  it, 
with  a' notch  cut  in  its  seam  to  receive  the  wire. 
It  also  assists  in  steadjang  the  plate,  which 
should  be  held  in  position  by  crib  clasps  on  the 
second  deciduous  molars.  The  plate  imme- 
diately behind  the  centrals  and  laterals  should 
be  cut  a\\ay  so  that  these  teeth  can  move  lingu- 
ally ;  it  must,  however,  remain  close  against 
the  canines,  as  these  usually  need  considerable 
expansion,  and  this  is  very  important. 

The  front  of  the  plate  should  be  thickened 
(and  the  edge  very  carefully  rounded)  so  that  the 
premolars  and  molars  cannot  occlude  ;  this  allow  s 
the  latter  to  elongate  or  rise  in  their  sockets,  and 
so  ultimateh'  prevent  the  low  er  incisors  touching 
the  soft  tissues  behind  the  upper  incisors.  As 
the  teeth  rise  to  occlusion  the  plate  should  be 
thickened,  so  that  the  same  movement  happens 
again,  and  so  on,  till  it  is  sufficient — it  should 


expand  the  lower  jaw  also.  This  may  be  in- 
serted after  the  other,  as  the  movement  required 
is  not  so  great ;  on  the  other  liand,  it  must  be 
remembered  that  movement  in  the  lower  jaw- 
is  usually  slower  than  in  the  upper.     The  upper 


Fig.  377. — Portrait  of  case  shown  in  Fig.  376. 
Compare  with  Fig.  375  and  note  the  cliange  in  profile  of 
the  dento-facial  area. 

jaw  should  be  kept  proportionately  more  ex- 
panded than  the  low  er  ;  this  w  ill  bring  the  medio- 
distal  occlusion  of  the  first  molars  correct  when 
the  bucco-lingual  relation  is  right.  By  treat- 
ment in  this  w  ay  the  low  er  jaw  may  be  expected 
to    move   forward   without   the   application    of 


Fig.  378.— C'asi- 


Before  treatment. 


proceed  in  this  way  by  very  small  stages  so  as 
not  to  disturb  mastication.  If,  at  the  very  end 
of  the  treatment  and  retention,  this  movement 
is  not  enough,  the  lower  incisors  and  canine? 
should  then  be  cut  shorter  to  such  an  extent 
that  normal  occlusion  is  possible.  If  this  is  not 
done  the  upper  centrals  w  ill  most  certainly  be 
pushed  out  again  by  the  lower  incisors. 

Lower  Jaw. — A  Badcock  plate  may  be  made  to 


direct  force  in  patients  iij)  i:i  ten  years  of  age. 
To  assist  this  the  thickened  front  of  the  upper 
plate  should  be  made  to  slope  upwards  and 
labially,  so  that  the  lower  incisors  tend  to 
slide  forward  on  it  as  they  strike  it.  Cleats 
should  be  fi.xed  in  the  vulcanite  to  engage  the 
occlusal  surfaces  of  the  first  permanent  molar 
or  second  deciduous  molar  on  either  side. 
Nothing  is  to  be  done  that  would  tend  to   pre- 


24  P 


vent  the  teeth  of  the  molar  series  elongating. 
For  this  reason  cleats  should  be  on  the  second 
deciduous  molars  whenever  possible ;  if  they 
must  be  on  permanent  teeth  their  position 
should  be  changed  from  time  to  time.  The 
case  should  be  continuously  retained  for  at 
least  two  years ;  after  that  period  the  retention 
appliance  may  be  worn  at  night  only. 


second  deciduous  molars  and  united  by  a  buccal 
wire  ;  lingual  extension  wires  engaged  the  first 
permanent  molars  and  the  first  right  deciduous 
molar.  In  the  lower  jaw,  a  lingual  wire  was 
used  extending  from  one  first  permanent  molar 
to  the  other,  with  spin's  to  prevent  the  space 
for  the  first  right  premolar  being  encroached 
on  by  the  adjacent  teeth. 


Fig.  379. — Case 


After  treatment. 


Treatment  of  the  lower  teeth  was  by  fixed 
appliances  in  this  particular  case,  because  the 
right  canine,  lateral,  and  central  had  fallen 
back  into  the  space  previously  occupied  by  the 
first  deciduous  molar ;  were  it  not  for  this 
complication,  treatment  with  a  removable  appli- 
ance would  have  been  exactly  as  outlined. 

Luken's  bands  weie  cemented  to  the  second 
deciduous  molars  and  a  German  silver  bow  was 
adjusted,  spurs,  inclined  medially,  being  soldered 
to  it  just  medial  to  the  right  canine,  lateral, 
and  central.  The  bow  was  given  spring  to 
exjiand  the  molar  series,  lingual  spurs  extending 
to  the  first  permanent  molars  from  the  clamp- 
bands. 

The  left  lateral  and  central  were  ligatured 
direct  to  the  bow,  and  the  right  canine,  lateral, 
and  central  also  to  the  bow,  with  its  spurs 
intervening ;  the  effect  of  the  three  latter  liga- 
tures was  to  move  medially  the  teeth  to  which 
they  are  attached.  This  movement  was  assisted 
by  turning  the  nut  on  the  right  side  against  the 
buccal  tube,  so  as  to  carry  the  bow  for\\ard  or 
to\\ards  the  left.  The  anchorage  was  ample, 
for  the  second  deciduous  molar  is  supported 
distally  by  the  first  permanent  molar. 

Retention  was  by  fixed  appliances.  Li  the 
upper  jaw,  plain  bands  were  fixed  to  the  four 


Fifteen     visits    were    required, 
treatment  are  shown  in  Fig.  379. 


Results    of 


H.  C. 


(1) 
(2) 
(3) 

(4) 

(5) 

(6) 

(■) 

(8) 

(9) 

(10) 
(11) 

(12) 
(13) 


BIBLIOGRAPHY 

Angle,  E.  H.     Dental  Cosmos,   1913,  Vol.  LV, 

No.  1,  p.  1. 
Case,  Carl  B.     Occipital  and  Cervical  Anchorage. 

Items  of  Interest,  May  1913,  Vol.  XXXV,  p.  332. 
Grieves,  C.  J.     Base  Metal  versus  Noble  Metal 

Appliances  in  Orthodontia.     Items  of  Interest, 

1909,  Vol.  XXXI,  p.  326. 
Jackson.  Victor  Hugo.    Ortliodontiaand  Ortho- 

paedia  of  the  Face.     Trans.  Fifth  International 

Dental  Congress,  1909.     Vol.  II,  p.  273. 
Jackson,  Victor  Hugo.    Orthodontia  and  Ortho- 

pacdia  of  the  Face.     1904. 
KoRBiTZ,  A.     Ash's  Quarterly  Review,  July  1910, 


AsJi's  Quarterly  Review,  Oct.  1910, 


p.  420. 

KORBITZ,  A. 

p.  580. 
PuLLEN,   H.   A.      Items  of  Interest,  Nov.    1911, 

Vol.  XXXIII,  p.  829. 
PuLLEN,    H.   A.      Items  of  Interest,    1912,   Vol. 

XXXIV,  p.  179. 
PuLLEN,  H.  A.     Johnson's  Operative  Dentistry. 
Wheeler.  C.  W.  B.     Dental  Cosmos,  Sept.   1911, 

Vol.  LIII,  p.  1011. 
Young,  J.  Lowe.     Items  of  Interest,  Feb.   1912, 

Vol.  XXXIV,  p.  110. 
Young,  J.  Lowe.     Itctns  of  Interest,  Nov.   1913, 

Vol.  XXXV,  p.  815. 


CHAPTER    XI 

SALIVA  AND   CALCULUS 


A.  SALIVA 

The  saliva  is  the  product  of  the  three  j)airs 
of  salivary  glands — parotid,  sub-iiiaxillary  and 
sub-lingual — and  of  the  mueousfollicles  scattered 
over  the  lining  of  the  mouth,  on  the  palate, 
cheeks,  and  inner  aspects  of  the  lips.  It  is  a 
colourless,  slightly  opalescent,  viscid  fluid, 
without  taste  or  odour.  It  facilitates  mastica- 
tion and  deglutition  by  lubricating  the  food, 
and  subserves  the  sense  of  taste  by  dissolvhig 
the  ingredients  that  provide  flavour  and  so 
bringmg  them  into  intimate  contact  with  the 
taste  buds  of  the  vallate  papfllae. 

The  composition  of  mixed  saliva  varies,  but 
one  analysis  gives  in  1000  parts  by  weight — 


Water 

.     994-203 

Mucin  .... 

2-202 

Ptyalin 

1-390 

Carbonates 

Phosphates 

Salts 

Chlorides . 
Sulphates 
Nitrates  . 

2-205 

1000000 

Parotid  saliva  is  clearer,  more  limpid,  less 
viscid,  and  more  alkaline,  than  the  mixed 
secretion.  It  contains  less  mucin.  It  deposits 
calcium  carbonate  on  standing,  owing  to  the 
escape  of  carbon  dioxide.  Sub-maxillary  saliva 
is  more  viscid,  and  contains  more  mucin  and 
salts  than  parotid.  Many  substances  besides 
those  mentioned  in  the  above  table  are  met  with 
in  specimens  of  saliva,  and  will  be  discussed 
later.  They  have  not  been  included  because 
they  cannot  with  certainty  be  regarded  as 
normal,  though  of  frequent  occurrence. 

The  ptyalin  of  the  saliva  is  manufactured  by 
the  specific  activity  of  the  gland  epithelium. 
The  water  and  the  saline  constituents  probably 
pass  into  the  secretion  by  osmosis  through  the 
walls  of  the  acini  from  the  lymph  channels 
outside.  Hence  the  amount  of  ptyalin  formed 
will  be  influenced  mainly  liy  the  proper  secretory 
nerves  of  the  gland,  whilst  the  water  and 
soluble  saline  ingredients  will  depend  upon  the 
state  of  dilatation  or  constriction  of  the  gland 
vessels,  and  also  upon  the   com^JOsition  of   the 


247 


blood  plasma  (and  hence  tlie  lymph  brought 
to  the  gland). 

Many  substances  abnormally  present  in  the 
blood,  or  present  hi  abnormal  amount,  appear 
in  the  saliva,  as  in  the  urine,  and  the  examina- 
tion of  the  secretion  has  prol)al)ly  a  cluiical 
importance  only  begmning  to  be  appreciated. 

The  specific  gravity  of  mixed  saliva  is  about 
1-003.  The  average  quantity  is  about  48  oz. 
in  24  hours.  It  is  increased  in  pregnancy,  tabes, 
bulbar  paralysis,  stomatitis  (especially  mer- 
curial), scurvy,  malignant  disease  of  the  tongue, 
and  other  diseases.  The  infliction  of  pain  upon 
the  teeth  or  lining  of  the  mouth  nearly  always 
causes  a  sudden  and  temporary  reflex "  increase 
in  the  flow ;  and  the  same  result  often  occurs 
at  the  sight  of  food,  or  through  psychic  action 
when  the  mind  is  dh-ected  to  it.  On  the 
other  hand,  the  emotion  of  sudden  fear  often 
causes  an  inhibition  of  the  flow  and  a  dry 
mouth. 

Pawlow,  studying  the  secretion  of  each  of  the 
main  glands  separately,  by  fistulae  established 
in  the  dog,  finds  that  the  physical  as  well  as  the 
chemical  character  of  the  food  has  a  distinct 
influence  on  the  reflex  salivary  flow.  Dry 
substances  excite  chiefly  a  parotid  secretion, 
wliile  the  same  substances  in  a  moist  state 
excite  chiefly  the  sub-maxillary;  the  parotid 
is  pre-eminently  the  flushing  gland,  providing 
fluid  to  wash  out  foreign  or  nauseous  particles. 
An  exception  to  this  is  milk,  which,  though 
fluid,  excites  a  copious  salivary  flow ;  the  reason 
is  that  milk  forms  a  looser  and  more  digestible 
curd  with  the  gastric  juice  when  saliva  is 
plentiful  in  the  mixture  than  when  it  is  scanty 
in  amount. 

The  nerve  centre  concerned  in  the  reflex 
secretion  of  saliva  is  the  "  nucleus  ambiguus  " 
in  the  medulla  oblongata,  and  it  can  be  stirred 
into  activity  by  afferent  impulses  through  the 
sensory  nerves  of  the  mouth,  and  also  by  way 
of  the  eye,  ear,  nose,  and  other  channels,  as 
well  as  by  psychical  action  of  the  cortex.  The 
afferent  paths  through  the  eye,  car,  nose,  etc., 
probably  gain  access  to  the  centre  in  the  medulla 
by  connections  that  they  establish  in  the 
cerebral  cortex.  It  is  easy  to  see,  therefore, 
that  mental  conditions  can  affect  these  salivary 
reflexes,  some  favouring  them  and  some  im- 
peding them  (31). 


248 


Sialagogues  are  drugs  that  increase  the 
flow  of  saliva.  They  act  either  by  entering 
the  blood  stream  and  stimulating  the  secreting 
cells  of  the  glands  (du-ect  or  specific),  or  by 
producing  a  reflex  dilatation  of  the  glandular 
vessels  through  then-  action  on  the  Iming  of 
the  mouth  (reflex  sialagogues).  Some  drugs 
act  in  both  ways. 


Specific  Sialagogues. 
Jaborandi  (Pilocarpine) 
Nicotme  (Tobacco) 
Muscarine. 

Physostigmine. 
Compounds  of  lodme. 
Mercury   and   its    Coni-\ 
pounds.  J 


Reflex  Sialagogues. 
Acids. 
Alkalies. 
Ethereal  bodies. 
Pungent  Substances. 
Tobacco. 
Nauseants. 
Ipecacuanha. 
Tartar  Emetic. 


Anti-sialagogues,  which    lessen    the    salivary 
flow,  may  act — 

(1)  By  inducing  a  healthier  state  and  lessening 

the  irritability  of  the  mucous  surface 
(borax,  potassium  chlorate) ; 

(2)  By  dimmishing  the  reflex  excitability  of 

"the  nerve  centre  (opium,  morphine) ; 

(3)  By   paralysmg   the   terminations    of   the 

secretory  nerves  (belladonna,  atropine). 

The  quantity  of  saliva  varies  greatly  in  dif- 
ferent individuals  and  states  of  health.  "  Dry  " 
mouths  and  "  wet  "  mouths  are  matters  of 
common  knowledge  to  dental  surgeons,  and  are 
the  cause  of  some  of  their  daily  difliculties. 
The  adhesion  of  artificial  dentures  is  apt  to 
fail  where  the  saliva  is  small  m  amount,  ^^•hfle 
a  too  copious  flow  increases  operative  difficulties. 
The  means  of  overcommg  these  will  bo  described 
elsewhere  (see  Chapter  XIX,  p.  337),  but  it 
may  be  mentioned  here  that  the  injection  of 
J^-'th  gr.  of  atropine  one  hour  before  operation 
has  been  recommended  for  controlling  excessive 
salivary  flow.  The  saliva  holds  in  suspension 
epithelium  cells  cast  off  from  the  mucous 
surface,  salivary  corpuscles,  which  are  supposed 
to  be  altered  leucocytes,  food  debrLs,  and  many 
micro-organisms.  In  many  fevers  the  saliva 
Ls  much  dinunished  in  quantity,  and  the  mouth 
breathing  that  generally  accompanies  states  of 
feebleness  and  depression  favours  the  evapora- 
tion of  water,  and  the  deposit  upon  the  lips, 
teeth,  and  gums,  of  crusts  or  films  called  sordes. 
These  deposits  consist  of  the  above-mentioned 
matters  agglutinated  by  thickened  mucus.  A 
simUar  deposit  of  less  density  often  to  be  found 
on  unclean  teeth  has  been  called  the  materia 
alba. 

Reaction  of  Saliva. — Normally  the  saliva  is 
neutral  or  faintly  alkaline,  but  it  easily  becomes 
acid  o«  in"  to  the  occurrence  of  acid  fermenta- 


tion, or  to  the  appearance  in  excess  of  some 
acid  constituent,  such  as  mucin  or  acid  sodium 
phosphate.  The  morning  saliva  is  often  acid. 
The  acidity  is  reduced  by  taking  meals,  and 
rises  again  towards  the  time  for  the  next  meal. 

Viscidity  of  the  Saliva. — This  is  chiefly  due 
to  mucin,  and  may  reach  such  a  degree  that 
the  saliva  can  be  drawn  out  mto  long  strings, 
and  camiot  be  poured  from  one  vessel  to  another 
in  the  manner  of  a  true  liquid,  but  is  dra^vn  over 
the  vessel  margin  in  mass  as  soon  as  the  transfer 
has  started.  The  effect  of  such  a  condition 
m  agglutmating  debris  upon  the  teeth,  and  in 
rendering  cleansing  difficult,  will  be  obvious. 
Black  distinguishes  between  ordinary  viscidity 
of  the  saliva  and  a  glutinous  deposit  which  is 
less  well  known  and  forms  upon  some  teeth 
owing  to  the  saliva  being  unable  to  hold  it  in 
solution.  He  believes  it  to  be  mamly  mucin, 
but  it  has  not  been  much  examined.  Tlie  deposit 
is  msoluble  in  the  saliva  of  the  person  in  whom 
it  is  found,  but  soluble  in  the  saliva  of  one  not 
affected  by  it ;  it  may  be  of  some  importance 
in  formmg  a  covering  for  organisms  and  their 
products,  and  holding  these  in  contact  with  the 
teeth  (3). 

Constitution  of  the  Saliva  in  Health  and 
Disease. — It  may  safely  be  assumed  that  normal 
saliva  is  the  best  fluid  m  which  teeth  can  be 
bathed ;  smce  nature  always  tends  to  adapt 
an  organ  and  its  environment  in  the  most 
perfect  mamier  possible.  But  great  uncertainty 
exists  as  to  what  is  normal  in  the  saliva  and 
what  abnormal.  The  many  published  analyses 
of  saliva  differ  considerably,  and  until  a  few 
years  ago  scarcely  any  attempts  had  been  made 
to  correlate  the  varying  composition  of  the 
saliva  with  different  states  of  health. 

Michaels  (25)  considers  that  many  deviations 
from  a  condition  of  health  are  indicated  by 
special  changes  m  the  composition  and  physical 
properties  of  the  saliva.  As  affecting  the  teeth 
and  tlieir  surrounding  structures  he  distmguishes 
bet\\'een — 

(1)  Normal  saliva; 

(2)  The  saliva  of  the  hypo-acid  diathesis ; 

(3)  The  saliva  of  the  hyper-acid  diathesis. 

In  the  hypo-acid  diathesis  there  is  increased 
body  metabolism,  and  oxidations  and  "  hydra- 
tions "  are  above  the  normal.  The  acidity  of 
the  body  fluids  is  dimmished,  because  the  normal 
end-products  of  nitrogenous  metabolism  are 
less  acid  than  those  that  are  formed  in  the 
intermediate  stages.  This  state  of  thmgs  is 
found  in  many  wastmg  diseases,  such  as  tuber- 
culosis and  syphilis ;  it  also  occurs  in  many 
people  unaffected  by  any  distmct  disease,  but 
predisposed  by  their  habit  of  body  (lymphatic) 
to  affections  of  the  above  type. 


249 


In  tlie  liyper-acid  diathesis  the  body  meta- 
bolism is  diminished  or  retarded,  the  oxidations 
are  imperfect,  and  tlie  intermediate  products 
of  metabolism,  being  less  soluble  and  more 
acid  than  the  normal  end-products,  accumulate 
in  the  body,  increase  the  acidity  of  the  tissues, 
organs,  and  fluids,  and  appear  in  places  from 
which  they  are  normally  absent.  This  condi- 
tion is  found  in  rheumatism,  gout,  diabetes, 
albuminuria,  neurasthenia,  arterio-sclerosis, 
eczema,  liver  affections,  and  also  in  those  who 
though  not  attacked  by  any  of  these,  are  yet 
predisposed  to  them  by  their  habit  of  body. 

Hypo-acid  saliva  contains  excess  of  glycogen, 
albumin,  mucin,  basic  chlorides,  and  ammonia ; 
but  less  than  the  average  amount  of  sulpho- 
cyanides  and  acid  biliary  salts.  It  is  an  ideal 
medium  for  the  develojJment  of  bacteria. 

Hyper-acid  saliva  contains  excess  of  sulpho- 
cyanides,  acid  mineral  and  organic  salts  (acid 
phosphates  of  sodium  and  calcium),  oxalates, 
acid  biliary  salts,  bUe  pigments,  and  urobilin. 
It  is  a  medium  more  suitable  for  the  develop- 
ment of  mycophvtic  fungi  than  for  bacteria. 

The  bearing  of  these  researches  on  the  question 
of  the  cause  of  caries  w  ill  be  discussed  elsewhere 
(see  Chapter  XIII,  p.  291),  but  it  camiot  be 
said  that  general  agreement  has  been  reached. 
Michaels  considers  that  much  depends  on  the 
relative  proportions  of  sulphocyanic  acid  and 
ammonia  present.  In  normal  saliva,  if  present 
at  all  they  are  equal,  and  both  very  small  in 
amount ;  the  reaction  is  neutral,  and  caries 
small  ill  extent  or  absent.  Where  the  annnonia 
is  in  excess,  there  is  great  tendency  to  caries 
(hyjio-acidity),  whilst  a  relatively  large  propor- 
tion of  sulphocyanic  acid  (hyper-acidity)  results 
in  immunity  from  or  slight  affection  by  caries. 

Some  observers  consider  that  sulphocyanides 
have  a  direct  inhibitory  effect  on  acid-producing 
organisms,  or  on  those  that  peptonize  and  dis- 
integrate the  organic  tooth  matrix  after  decalci- 
fication, and  in  this  belief  advise  the  adminis- 
tration of  potassium  sul])hocyanide  ui  cases  of 
caries  where  sulphocyanides  have  been  proved 
to  be  sub-normal  in  amoiuit.  Others  think  that 
a  high  percentage  of  sulphocyanide  merely 
coincides  with  the  absence  from  the  saliva  of 
some  constituent  that  when  present  makes  it 
a  suitable  pabulum  for  the  growth  of  organisms 
(12). 

Michaels  believes  that  the  sulphocyanide 
most  regularly  present  in  hyper-acidity  is  that 
of  ammonium,  but  that  in  some  rheumatic 
subjects  it  is  replaced  by  the  potassium  or 
sodium  salt,  and  in  these  persons  chemical 
erosion  is  met  with  frequently.  He  also  dis- 
tinguishes between  the  rheumatic  and  gouty 
branches  of  the  hyper-acid  diathesis.  In  the 
gouty,  sulphocyanides  are  often  absent  from 
the  saliva  or  small  in  amount.     The  aciditv  is 


due  to  acid  phosphate  of  sodium  ;  caries  is  more 
frequent  than  in  rheumatic  persons,  and  disease 
of  the  structures  surrounding  the  teeth  ("  pyor- 
rhoea ",  etc.)  often  met  with.  The  fermentations 
takhig  place  in  gouty  and  diabetic  salivas  pro- 
duce lactic  acid  ;  those  occurring  in  rheumatic 
salivas,  oxalic  acid. 

Michaels  states  that  the  salivary  and  buccal 
mucm  is  precipitable  hi  a  feebly  acid  medium, 
after  combination  with  ammonia,  as  a  cheesy 
deposit,  which  occurs  both  on  the  surface  of 
the  gums  and  the  labial  aspects  of  the  teeth. 
In  rheumatic  subjects  this  deposit  does  not 
itself  ferment,  but  does  not  prevent  caries. 
Michaels  believes  that  m  presence  of  sulpho- 
cyanic acid,  the  glucoside  factor  in  it  becomes 
reduced  to  oxalic  acid,  which  gives  such  caries 
as  is  present  its  peculiar  black  colour.  In 
gouty  and  diabetic  subjects,  sulphocyanic  acid 
being  less  in  amount,  the  deposit  does  ferment 
by  contact  with  organisms,  jnoducing  lactic 
and  butyric  acids.  In  these  patients  thcT acidity 
that  determuics  the  precipitation  is  due  to 
acid  phosphate  of  sodium.  This  glyco-muci- 
genous  con.stituent  of  the  saliva  is  not  precipi- 
tated at  all  upon  the  teeth  or  gums  in  the  hypo- 
acid  diathesis,  since  the  saliva  is  there  neutral 
or  alkalme.  The  fermentation  of  this  deposit 
is  distinct  from  that  occurruig  in  food  debris 
under  the  action  of  micro-organisms.  The 
latter  can  occur  in  any  saliva,  but  is  more 
active  in  hyjio-acid  than  m  hyper-acid,  beiag 
inhibited  by  the  sulphocyanic  acid  present  in 
the  latter.  Possibly  this  deposit  of  cheesy 
material  may  be  the  same  as  that  described 
by  Black  {vide  supra).  Knowledge  of  the 
behaviour  of  the  constituents  of  the  saliva  is 
as  yet  very  incomplete. 

Miller,  writing  after  the  date  of  Michaels' 
publication,  was  of  opinion  that  no  constituent 
of  the  saliva  in  the  strength  in  which  it  was 
present  in  the  secretion  had  any  influence  on 
microbial  action. 

Reference  to  other  studies  of  the  saliva, 
and  schemes  for  the  detection  and  estimation 
of  various  constituents,  will  be  found  m  the 
Bibliography  under  Nos.  8,  10,  12,  13,  14,  17, 
22,  and  29. 

Chemiotaxis. — It  has  long  been  noticed  tliat 
althougli  the  mouth  swarms  with  micro- 
organisms, and  no  wound  communicating  with 
the  mouth  can  be  aseptic,  or  efficiently  treated 
antiseptically,  yet  lesions  in  this  region  heal 
surprisingly  well,  and  systemic  infection  from 
them  is  comparatively  rare.  Some  wounds, 
when  deliberately  made  and  carefully  sut\ircd, 
heal  by  first  intention  ;  as,  for  mstance,  those 
made  in  successful  operations  for  cleft  palate. 
There  are  several  anatomical  reasons  for  this. 
The  wounded  parts  are  soft  and  pliable  and  have 
an   abundant    blood   supply ;     hence   migration 


250 


of  leucocytes  will  be  free,  and  phagocytic  action 
vviU  have  every  chance  to  be  efficient.  More- 
over, as  the  parts  are  bathed  with  fluid  con- 
stantly renewed,  the  discliarges  are  removed  as 
quickly  as  they  are  formed,  and  prevented  from 
drying  and  gluing  together  the  edges  of  the 
wound,  witli  consequent  retention  of  septic 
matter  in  its  deeper  parts.  Septic  matter  fre- 
quently does  not  produce  either  severe  local 
effects  or  systemic  mfection  if  the  means  of  exit 
are  free  and  the  material  is  not  confined  under 
tension. 

The  above  considerations  seem,  however, 
uisufficient  to  explain  the  marked  immunity 
from  serious  consequences  that  exists  in  the 
case  of  rounds  of  the  mouth,  and  inquiries  have 
been  made  whether  this  can  be  due  to  any 
antiseptic  or  other  benign  mfluence  exerted  by 
the  saliva. 

Protective  powers  might  be  due  to  the  fol- 
lowing-— • 

(1)  An  antiseptic  or  bactericidal  quality  m 

the  secretion. 

(2)  A    "  chemiotactic  "    quality,    causing    a 

determination  of  phagocytes  to  the 
wounded  part,  the  phagocj'tes  then 
destroying  the  organisms  by  mgestion. 

(3)  The  presence  in  the  saliva  of  substances 

similar  to  the  alexms  of  the  blood 
plasma,  which  neutralize  the  poisons 
formed  by  the  bacteria  (antitoxic 
action),  or  which  destroy  or  weaken  the 
bacteria  themselves. 

(4)  The  presence  in  the  saliva  of  a  number  of 

harmless  organisms,  thoroughly  habitu- 
ated to  their  surroundings — the  normal 
flora  of  tlie  buccal  cavity — ,  which,  hi  the 
struggle  for  existence,  by  monopolizing 
pabulum,  etc.,  hinder  the  development 
of  more  dangerous  species  whose  vigour 
may  be  depressed  by  surrounduigs 
partially  unsuitable  to  them. 

Miller  was  of  opinion  that  the  saliva  had  no 
power  to  prevent  or  retard  the  growth  of 
bacteria,  and  he  found  in  it  no  substances  like 
the  alexhis  of  the  blood.  In  addition  to  the 
alexins,  which  act  indifferently  against  any 
organism,  the  blood  often  contains  specific 
protective  bodies,  which  act  only  agamst  the 
poison  that  called  forth  their  existence ;  some 
of  these  probably  do  appear  in  the  saliva.  The 
curative  effect  exercised  by  the  saliva  of  snake- 
charmers  when  applied  to  the  bite  of  a  venomous 
reptile  is  evidence  of  this.  These  men  acquire 
immunity  by  allowmg  themselves  to  be  bitten 
by  a  succession  of  snakes,  each  more  venomous 
than  its  predecessor.  A  supply  of  antitoxin  is 
developed  in  their  blood  and  some  of  this  seems 
to  appear  m  their  saliva.     The  saliva  of  persons 


suffering  from  diphtheria  and  pneumonia  prob- 
ably contains  the  specific  antitoxic  substances 
of  those  diseases. 

The  chemiotactUe  po\\'er  of  saliva  was 
mvestigated  by  Hugenschmidt,  who  fiUed 
capUlary  glass  tubes  with  saliva,  sealed  up  one 
end,  inserted  them  under  the  skui  and  mto  the 
peritoneal  cavity  of  rabbits  and  found  after 
a  few  hours  that  the  open  ends  of  the  tubes  were 
plugged  by  masses  of  phagocytes.  Miller  found 
great  numbers  of  leucocytes  loaded  \\ith  bac- 
teria in  the  discharges  from  post-extraction 
wounds.  In  these  cases,  however,  the  phago- 
cytes might  have  been  attracted  to  the  spot  by 
the  organisms  contamed  m  the  saliva.  Hugen- 
schmidt's  experiment,  conducted  with  germ- 
free  saliva  obtahied  by  filtration  tlu-ough  porce- 
lain, showed  a  very  slight  flockmg  of  leucocytes 
to  the  capillary  tube  orifice.  It  would  thus 
seem  that  the  supposed  chemiotactic  properties 
of  saliva  are  really  due  to  the  organisms  that 
it  contains. 

On  the  whole,  Miller  considered  that  "the 
protective  powers  present  in  the  human  mouth 
are  not  to  be  accounted  for  by  any  antiseptic 
action  on  the  part  of  the  saliva,  but  rather  by 
the  phenomenon  of  phagocytosis,  by  the  struggle 
for  existence,  and  probably  by  certain  forces 
residing  m  the  soft  tissues  which  have  not  yet 
been  mvestigated  "  (26). 

With  regard  to  this  last  pouit  it  may  be  men- 
tioned that  when  saliva  bathes  a  raw  surface 
of  tissues  unaccustomed  to  the  presence  of  the 
secretion,  it  certauily  does  not  conduce  to 
healing ;  smce  it  has  long  been  known  as  the 
chief  obstacle  to  the  closure  of  a  salivary  fistula 
opening  externally. 

The  active  digestive  ferments  in  the  m- 
testinal  canal  are  rendered  inactive  during 
their  absorption  through  the  intestinal  wall, 
and  it  is  quite  possible  that  immunity,  natural 
or  acquired,  is  nothmg  more  than  an  extension 
of  the  protective  power  that  Ls  constantly  exer- 
cised during  digestion  by  the  cells  of  the  intes- 
tine and  liver  towards  those  of  the  tissues 
generally  (19). 

B.  CALCULUS 

Calculus  or  Tartar  is  a  deposit  which  occurs 
upon  the  teeth  and  often  on  artificial  dentures. 
It  is  composed  of  various  salts  and,  incorporated 
witli  them,  a  certain  amount  of  organic  matter, 
cast-off  epithelium,  pus  cells,  mucin,  food 
debris,  organisms,  etc.,  which  by  their  putre- 
faction add  to  the  offensive  smell  that  makes 
tartar  one  of  the  causes  of  foul  breath.  There 
are  two  varieties  of  tartar,  called  "  saUvary  " 
and  "serumal  " — terms  indicating  the  supposed 
origin  of  one  kind  from  the  saliva  and  the 
other  from  the  blood  serum.     Opinions  differ  as 


251 


to  the  validity  of  this  disthictioii,  but,  no  doubt, 
there  are  two  clinical  varieties. 

Salivary  Calculus  on  Teeth  is  found  most 
abundantly  on  the  luigual  aspect  of  the  lower 
front  teeth  and  the  buccal  aspect  of  the  upper 
molars — in  close  proximity,  that  is,  to  the 
orifices  of  the  main  salivary  ducts.  It  is  of 
varying  density  and  colour,  becommg  harder 
and  darker  the  more  slow  ly  it  is  deposited.  In 
smokers  the  tartar  is  stamed  black,  especially 
if  small  in  amount. 

It  begms  as  a  Imear  deposit  on  the  neck  of 
the  tooth  at  the  gum  margin,  and  as  it  grows  in 
amount  encroaches  on  the  crown  and  may 
entirely  cover  it.  The  deposit  becomes  thicker 
by  addition  to  its  free  surface,  and,  most 
important  of  aU,  gradually  spreads  downwards 
and  pushes  the  gum  away  from  the  neck  of 
the  tooth  by  additions  to  the  gingival  aspect  of 
the  mass.  It  thus  ultimately  exposes  and 
encrusts  the  root  for  a  variable  distance, 
while  a  prominent  shelf  is  produced  overhang- 
ing the  gum  margin.  Beneath  thLs  ledge,  food 
debris,  organisms,  and  cast-off  epithelial  squames 
lodge,  and  by  putrefaction  increase  tlie  evil 
consequences  of  the  calculus.  These  sequelae 
are  chronic  mtlammation  of  the  gum  margins, 
chronic  mflammation  and  progressive  destruc- 
tion of  the  periodontal  membrane  with  de- 
tachment of  it  from  the  cementum,  and  slow 
osteitis  with  wastmg  of  the  margins  of  the 
alveolus,  resultmg  in  more  or  less  destruction 
of  the  bony  socket  (see  Chapter  XXX).  The 
teeth  necessarily  loosen,  and  in  many  cases 
drop  out.  The  deposit  is  retarded  by  attention 
to  cleanliness,  though  in  many  cases  it  cannot 
be  prevented  by  the  unaided  efforts  of  the 
patient;  it  almost  always  increases  greatly  on 
teeth  not  used  to  the  proper  extent  ui  masti- 
cation, either  becau.se  they  are  painful  or  have 
lost  their  opponents. 

Composition. — This  necessarily  varies.  Com- 
monly quoted  analyses  are — 


Water  and  organic  matter 

Magnesium  phospliate 

Calcium  phosphate  with  a 

little      carbonate       and 

fluoride    .... 

Soft  Molar 
Calculus. 

21-48 
1-31 

77-21 

Hard  Incisor 
Calctdus. 

17-51 
1-31 

81-18 

100-00 


100-00 


Soft  and  rapidly  deposited  tartar  contains 
more  water  and  organic  matter  than  hard  and 
slowly  formed  varieties.  Calculus  deposited 
mainly  from  parotid  saliva  contains  more 
carbonates  and  less  phosphates  than  that  from 
the  sub-maxillary  and  sub-lingual  secretion. 

Cause  of  the  Deposit. — When  saliva  reaches 
the  mouth  carbonic  acid  gas  escapes,  and    the 


salts  contained  in  the  saliva  pass  from  an  acid 
to  a  neutral  condition,  in  which  their  solubility 
is  less  and  i\wy  are  more  prone  to  be  precipitated. 
The  comparative  freedom  from  tartar  in  cases 
where  the  saliva  is  viscid  and  stringy  may  in  j)art 
be  due  to  the  character  of  the  fluid  lundering 
the  escape  of  carbonic  acid.  "  Mouth-breath- 
ing "  will  probably  facilitate  the  escape  of 
carbonic  acid  and  the  evaporation  of  water 
from  the  saliva,  and  will  thus  predispose  to  the 
dejjosit  of  tartar. 

Sub-gingival  Calculus. — This  variety  occurs 
as  a  hard  annular  depo.sit  on  the  nocks  of  teeth 
just  below  the  gum  margin.  There  is  often  no 
evidence  of  gingival  mflammation,  but  some- 
times this  is  present.  The  deposit  may  increase 
in  amount  and  cover  the  root  further  and  further 
towards  the  apex.  In  these  cases  the  gum 
is  detached  from  the  cementum  and  either 
atrophies  or  forms  pockets  from  which  pus  can 
be  squeezed.  The  periodontal  membrane  and 
the  bony  socket  are  destroyed  by  chronic 
inflammation,  and  the  root  may  thus  be  de- 
nuded nearly  to  the  apex.  This  is  ofteiiest 
seen  ui  the  palatme  roots  of  the  upper  molars. 
As  the  deposit  increases,  the  inflammation  of 
surrounding  parts  becomes  greater,  and  the 
case,  clinically  at  any  rate,  resembles  "  pyorrhoea 
alveolaris  ".  Sub-gingival  calculus  is  olive-green 
or  blackish  m  colour,  nodular  on  the  surface, 
tightly  adherent  to  the  root,  and  small  in 
amount,  compared  with  the  supra-gingival 
form.  In  composition  it  does  not  differ  much 
from  the  latter.  Its  greater  hardness  is  sup- 
posed to  be  due  to  its  slower  formation,  and 
its  dark  colour  to  chromogenic  bacteria,  or  to 
its  being  soaked  by  the  products  of  inflammation 
and  putrefaction. 

This  deposit  has  been  called  "  serumal  " 
calculus  by  some  who  believe  that  it  is  deposited 
not  from  the  saliva  but  from  the  blood  serum 
or  the  inflammatory  discharges  of  the  uiflamed 
gums.  It  is  difficult  to  prove  that  any  deposit 
m  a  -region  to  which  saliva  has  access  did  not 
come  from  the  saliva;  but  many  writers  (7,  18, 
24,  and  28)  maintain  that  hard  dark  "serumal  " 
calculus  forms  on  the  roots  of  teeth  in  positions 
inaccessible  to  the  saliva  and  beneath  an  intact 
gum  and  periodontal  membrane.  It  is  argued 
that  such  must  come  from  the  blood  tlirough 
the  lymph.  It  is  hard  to  be  certain  that  tlicro 
has  been  no  detachment  of  the  pericementum, 
and  that  the  region  of  the  calculus  is  absolutely 
shut  off  from  saliva  hi  any  case.  But  Miller 
reported  a  deposit  of  dark-green  calculus  on 
the  root  of  a  tooth  of  which  only  the  tip  of  the 
cusp  had  emerged  through  the  gum  ;  here  there 
is  a  strong  presumption  that  the  deposit  had 
a  source  other  than  the  saliva.  The  calculus 
found  under  an  intact  pericementum  is  believed 
by  many  observers  to  be  deposited  in  the  meshes 


252 


of  the  periodontal  membrane,  as  gouty  "  tophi  " 
or  "  chalk  stones  "  are  deposited  m  ligaments, 
tendons,  and  other  fibrous  tissues ;  and  to 
become  adherent  to  the  cementum  secondarily. 
The  irritation  of  its  presence  is  thought  to  cause 
some  of  the  occasional  abscesses  arising  in  con- 
nection with  teeth  whose  pulps  are  still  alive 
and  healthy  (haematocalcic  pericementitis).  In 
this  form  of  calculu.s,  as  well  as  in  the  sub- 
gmgival  form,  it  has  been  alleged  that  traces  of 
urates  were  present.  This  is  denied  by  many 
authors,  who  doubt  the  validity  of  the  murexide  ' 
test  in  these  circumstances,  and  thhik  that 
the  colouration  observed  is  due  to  some  other 
organic  substances  present  (32). 

Burchard  (7)  classifies  the  forms  of  calculus 
as  follows — 

(1)  That  deposited  from  the  saliva  (ptyalo- 

genic  calculus). 

(2)  That  deposited  from  the  blood  serum — 

(a)  after  fermentation  and  altered  secre- 
tion from  the  gum  margm  (sub- 
gingival calculus) ; 

{b)  where     chronic     pus     flow    is      found, 
whether    apical    or    sub-gmgival 
(pyogenic  calculus) ; 

(c)  where  no  saliva  has  access  (haemato- 
genic  calculus  of  Pierce). 

The  forms  (a)  and  (6)  might  of  course  be 
deposited  partly  by  the  saliva  and  partly  by  the 
discharges  from  the  inflamed  soft  parts. 

Many  observers  do  not  see  in  the  varymg 
local  conditions  a  sufficient  explanation  of  the 
imnuinity  from  tartar  enjoyed  by  some  and 
its  varying  incidence  in  others.  They  consider 
that  calculus  has  a  constitutional  origin,  and 
that  it  is  one  of  the  symptoms  of  the  hyper -acid 
diathesis  of  sub-oxidation  {vide  supra).  The 
capacity  of  the  blood  stream  to  hold  in  solution 
the  products  of  nitrogenous  metabolism  depends 
on  the  alkalinity  of  the  blood  plasma.  Lessened 
alkalinity  may  be  general  or  local,  and  in  such  a 
condition  uratic  deposits  are  more  likely  to 
occur.  These  deposits  show  a  predilection  for 
fibrous  tissues  and  for  tissues  \vhose  local 
acidity  is  high  owing  to  the  amount  of  work  I 
and  consequently  of  tissue  change,  going  on 
in  them ;  such  are  ligaments  and  tendons,  and 
such  also  is  the  periodontal  membrane. 

The  general  alkalinity  of  the  blood  plasma 
is  greatly  lowered  hi  the  hyper-acid  diathesis. 
There  is  often  a  high  proportion  of  carbonic  acid 
in  the  blood  (30).  Since  calcium  phosphate 
and  carbonate  are  held  hi  solution  as  acid  salts 
by  reacting  upon  the  carbonic  acid,  it  may  be 
that  in  these  ca.ses  the  amount  of  tlio.se  salts 
in  the  plasma  is  more  than  normal.  In  the 
phosphatic  diabetes  of  Ralfe  and  Tessier  there 


is  an  abnormal  loss  oi  phosphates  by  the  urine 
before  any  sugar  appears  (19).  This  excess 
may  also  appear  in  other  secretions,  notably 
the  saliva,  and  as  the  chemical  affinity  between 
carbonic  acid  and  the  earthy  phosphates  and 
carbonates  is  very  weak,  the  combination  is 
easily  decomposed  with  escape  of  the  carbonic 
acid  and  the  precipitation  of  the  basic  phos- 
phates and  carbonates.  If  lymph  overloaded 
with  salts  reaches  an  area  of  inflamed  gum  or 
periodontal  membrane,  the  alkaline  products 
of  inflammation  may  decompose  the  union 
mentioned  above  and  precipitate  the  earthy 
phosphates  (18). 

Ivirk  believes  (loc.  cit.)  that  some  of  the 
organic  matter  in  calculus  is  a  colloidal  sub- 
stance furnished  by  the  mucin  of  the  saliva, 
which  unites  with  the  earthy  j^hosphates  in 
a  manner  comparable  with  the  formation  of 
calcoglobulin  in  the  process  of  calcification. 
According  to  these  views  "serumal"  calculus 
is  a  result,  and  not  a  cause,  of  inflammation, 
except  that  once  deposited  it  may  mcrease 
the  inflammation  by  its  irritative  effect  as  a 
foreign  body.  A  slight  deposit  of  urates  might 
first  occur  and  mflame  the  periodontal  mem- 
brane ;  pyogenic  infection  and  putrefaction 
might  then  ensue,  and  the  resulting  alkalinity 
cause  the  deposit  of  phosjihates  and  carbonates. 

Treatment. — The  local  treatment  of  tartar 
on  the  teeth  consists  m  thorough  removal, 
preferably  by  instruments.  Tartar  on  the 
crowns  and  necks  of  the  teeth  is  removed  by 
pressing  with  a  chisel-edged  instrument  in  a 
direction  from  the  masticatmg  surface  towards 
the  root  apex.  This  commonly  dislodges  the 
great  nia.ss  of  the  calculus,  and  the  remaining 
fragments  are  scraped  off  by  pulling  movements 
with  bent  instruments  passed  beyond  them. 
There  is  a  wide  choice  of  instruments  available. 
Excavators  may  be  used  for  deep-seated  frag- 
ments, and  specially  thin-bladed  instruments 
for  the  approximal  surfaces.  The  removal 
must  be  as  thorough  as  possible,  since  each 
particle  left  continues  the  u'ritation  and  acts 
as  a  nidus  for  further  deposit.  After  instru- 
mentation, all  surfaces  should  be  smoothed  and 
polished  as  far  as  possible  with  pumice  powder 
and  whitening  used  on  revolving  brushes  or 
buffs,  small  sticks,  and  strips  of  tape. 

Where  the  tartar  is  hard  and  deep-seated 
the  operation  is  very  difiicult  to  carry  out 
thoroughly ;  bruising  and  laceration  of  the  soft 
parts  may  be  inevitable,  and  a  local  anaestlietic 
may  be  of  assistance.  Repeated  operations 
are  often  necessary.  Owing  to  the  great 
difficulty  of  complete  removal  by  instruments, 
the  introduction  of  solvents  into  the  pockets 
of  the  gum  on  small  wooden  sticks  or  pledgets 
of  wool  has  been  recommended.  They  are 
generally    condemned    because    they    tend    to 


253 


decalcify  the  root  or  act  as  escharotics  to 
the  soft  parts.  The  «Titer  has  no  experience 
of  them,  but  sulphuric  acid,  aromatic  sulphuric 
acid,  and  trichloracetic  acid,  20-25%,  have 
been  used.  Head  has  more  recently  advocated 
the  use  of  acid  fluoride  of  ammonium  prepared 
in  a  special  manner  (11);  it  is  said  to  soften 
the  tartar  \\  ithout  affecting  the  tooth  substance, 
and  by  slight  irritation  to  induce  healthy 
granidation  around. 

When  the  teeth  are  much  loosened  by  absorp- 
tion of  their  sockets,  they  should  be  maintamed 
at  rest  for  a  time  by  \\u'mg ;  or  better,  by  thm 
metal  bands  made  for  the  loose  teeth  and  con- 
tiguous firm  teeth.  These  bands  are  soldered 
together  on  a  model,  and  the  whole  appliance 
is  cemented  on  the  teeth.  The  chronic  perio- 
dontitis set  up  by  the  calculus  and  the  want 
of  rest  then  subsides,  and  the  teeth  become 
much  firmer.  It  is  said  that  there  may  be 
some  restoration  of  the  socket  by  grow  th  of  new- 
alveolar  bone  (1).  However  this  may  be,  the 
gums  will  harden  and  contract  upon  the  tooth  ; 
but  it  is  doubtful  whether  gum  and  periodontal 
membrane  ever  become  re-attached  to  cemen- 
tum  from  which  they  have  been  separated  as 
the  result  of  calcidus. 

Calculus  in  the  Salivary  Ducts  and  Glands. 
This  is  due  to  the  deposit  of  calcareous  matter 
from  the  saliva  before  the  secretion  reaches 
the  mouth.  The  concretions  may  form  in  the 
ducts  or  in  the  alveoli  of  the  glands,  but  cases 
are  not  very  common.  Wharton's  duct  and 
the  sub-maxillary  gland  are  affected  more  often 
than  the  parotid  and  its  duct,  possibly  o\\ing 
to  the  greater  viscidity  of  the  sub-maxillary 
secretion,  and  to  the  fact  that  the  backward 
pressure  of  the  mandible  upon  the  parotid 
in  many  movements  of  the  jaw  must  assist  the 
flow  from  that  gland.  The  disease  is  more 
frequent  in  men  than  in  women,  and  betvceen 
40  and  50  years  of  age  than  at  other  periods 
of  life. 

The  stones  may  be  smgle  or  multiple ; 
they  are  u.sually  smaU,  about  the  size  of  a 
grain  of  corn,  but  have  been  met  \\ith  as 
large  as  a  hen's  egg.  They  consist  manily 
of  calcium  and  magnesium  phosphate,  with 
a  little  carbonate.  Triple  phosphates,  iron, 
sodium  chloride,  and  silicic  acid,  have  been 
found  as  traces.  Some  calculi  show  lammation, 
and  a  nucleus  apparently  consistmg  of  masses 
of  dead  organisms. 

The  symptoms  vary ;  but  typical  cases  show 
some  of  the  following  features.  The  patient 
may  be  seen  during  a  first  attack,  but  there  is 
often  a  history  of  previous  recurrent  attacks 
whicli  subsided  spontaneously,  owmg  perhaps 
to  the  e-scape  of  a  calculus  or  to  dilatation  of 
the  duct  lessenmg  the  obstruction.  There  may 
be  observed — • 


(1)  Lancmating  pain  in  the  region  of  the  duct 

or    gland,    increased    on    mastication, 
deglutition,    or   phonation. 

(2)  Swelling  in  the  region  of  the  gland,  or 

line  of  the  duct. 

(3)  Purulent  discharge  from  the  duct  orifice, 

due  to  ulceration  around  the  calculus 
or  septic  infection  of  the  retamed  saliva. 

(4)  Diffuse  stomatitis  and  salivation. 

(5)  Foetor  of  the  breath. 

A  calculus  iji  the  duct  may  be  felt  by  palpation 
along  the  course  of  the  canal,  or  by  dilating  the 
orifice  and  passing  a  probe ;  when  embedded  in 
the  gland  substance  the  stone  might  be  detected 
by  puncture  with  a  needle. 

If  the  retained  saliva  and  the  gland  become 
infected  with  septic  organisms,  there  will  be  red- 
ness, s\\elling,  and  increased  paui.  Rigors  and 
fever  may  follow.  Abscesses  may  form  in  the 
gland.  The  inflammation  may  spread  to  the 
cellular  tissue  of  the  floor  of  the  mouth,  and  the 
case  closely  resemble  Ludwig's  angina.  Suffo- 
cative paroxysms  may  occur.  The  lymphatic 
glands  of  the  neck  may  enlarge  and  suppurate. 
In  other  cases  the  symptoms  are  of  a  less 
urgent  type.  The  obstruction  may  result  in 
fibroid  iiiduration  of  the  gland,  and  the  case 
be  mistaken  for  carcinoma.  The  calculus  may 
ulcerate  through  the  waUs  of  the  duct  or 
through  the  gland,  and  escape  mto  the  mouth. 
Escape  externally  by  ulceration  through  the 
skin  is  rare  in  the  case  of  sub-maxillary  calculi, 
but  more  frequent  when  Stenson's  duct  or  the 
parotid  is  involved. 

Treatment. — When  localized  ui  Wharton's 
duct  or  the  sub-maxillary  or  sub-lingual  gland, 
the  stone  should  be  cut  down  upon  by  an  mcision 
withm  the  mouth,  and  removed;  when  in 
Stenson's  duct,  the  natural  orifice  should  be 
dilated  or  mcised,  and  an  attempt  made  to 
remove  the  calculus  with  small  forceps  or  scoops 
passed  along  the  duct.  If  necessary  the  calculus 
may  be  broken  into  several  pieces  by  needling 
or  crushmg,  and  these  removed  separately. 
Wien  the  stone  is  located  in  tlie  substance  of 
the  parotid,  it  should  still,  if  possible,  be  removed 
by  incision  from  the  mouth,  since  an  external 
wound  from  which  saliva  discharges  (salivary 
fistula)  is  by  all  possible  meaiis  to  be  avoided, 
owmg  to  the  difficulty  in  makuig  it  heal. 

Where  an  external  incision  into  the  sub- 
maxillary gland  has  been  made  it  is  perhaps 
better  to  remove  the  gland  entirely,  and  this 
is  also  recommended  where  the  gland  has  been 
disorganized  by  suppuration  or  rendered  useless 
by  fibroid  induration.  Salivary  fistulae  are  only 
of  importance  w  hen  they  open  externally.  The 
treatment  after  removal  of  the  calcidus  is  to 
ensure  a  free  passage  for  the  saliva  into  the 
mouth  by  dilating  or  incising  the  natural  orifice, 


254 


and  passing  a  draiii  from  the  deep  part  of  the 
fistula  into  the  mouth.  The  edges  of  the  fistula 
are  freshened  and  sutured  over  the  tube.  At- 
tempts at  closure  often  fail,  and  have  to  be 
repeated.  The  edges  of  the  fistula  may  be 
touched  with  the  actual  cautery,  or  plastic 
operations  be  done  (6). 

If  the  duct  is  obstructed  by  causes  other  than 
calculus,  periodical  pain  m  the  region  of  the 
gland  may  arise.  This  has  been  noticed  where 
the  orifice  of  Stenson's  duct  has  been  persistently 
nijjped  by  the  occluding  molar  teeth.  The 
treatment  is  to  grmd  the  offending  teeth  so  as 
to  make  nipping  impossible. 

Discolorations  of  Teeth  due  to  External  Deposit 

Green-stain  is  a  dirty,  greenish  discoloration, 
which  often  appears  on  the  teeth,  deciduous  and 
permanent,  soon  after  eruption.  It  is  commoner 
on  the  front  teeth  than  the  back,  and  on  the 
upper  than  the  lower.  It  is  most  abundant  along 
the  cervical  edge  of  the  enamel,  and  extends 
along  any  grooves  towards  the  uicisal  edge. 
It  appears  to  be  located  in  the  enamel  cuticle, 
since  its  distribution  corresponds  to  the  positions 
where  that  structure  persists  longest,  and  it 
immediately  disappears  when  the  cuticle  is 
freed  by  decalcification.  The  colouring  matter 
is  insoluble  in  water,  glycerine,  alcohol,  ether, 
chloroform,  and  turpentine  ;  hence  it  is  probably 
not  identical  w  ith  chlorophyll,  the  green  pigment 
of  plants,  as  was  at  one  time  supposed,  since 
the  latter  is  freely  soluble  in  ether.  Green-stain 
is  rapidly  bleached  by  chlorine  and  hydrogen 
dioxide.  Miller  regarded  the  stain  as  sulpho- 
methaemoglobin,  or  some  allied  substance.  The 
stain  is  now  believed  to  be  due  to  chromogenic 
bacteria,  which  have  been  found  in  the  de- 
posit. After  removal  of  the  stain  the  underlying 
enamel  is  often  found  unaft'ected,  but  sometimes 
appears  roughened  or  chalky,  as  from  mcipient 
decalcification. 

Various  other  stains  affect  the  teeth  ex- 
ternally— 

Tobacco  sometimes  imparts  a  brown  stain. 
Iron,  especially  ferric  salts  taken  as  medicine, 

causes    a    blackish    stain    from    iron 

sulphide. 
Mercury  may  cause  a   green   stain,   due  to 

sulpho-methaemoglobin  formed  beneath 

the  edges  of  inflamed  gums. 
Mercury  with  potassium  iodide  may  give  a 

green  deposit  of  iodide  of  mercury  on 

tlie  teeth. 
Copper  and  brass  sometimes  stam  the  teeth 

greenish  in  those  constantly  working 

in  these  metals.     A  similar  stain  often 

follow  s  amalgam  fUlhigs,  but  this  chiefly 

affects  the  dentijie. 


Treatment. — So  far  as  the  enamel  is  concerned 
the  stain  should  be  removed  by  abrasives ; 
pumice  powder  applied  on  revolving  buff  discs, 
pointed  pieces  of  cane,  or  strips  of  tape,  is 
effective  in  cases  of  green-stam  and  m  the  other 
classes  where  the  discoloration  is  entirely 
external.  Wliere  penetration  is  deep,  or  the 
stain  comes  from  witlim,  bleaching  has  to  be 
emploved  (see  Chapter  XXXI,  p.  523). 

C.  H.  P. 


(5 
(6 

(7 

(8 

(9 

(10 
(11 

(12 

(13 

(14 
(15 

(16 

(17 

(18 
(19 
(20 

(21 
(22 
(23 

(24 
(25 


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Barrett.      Dental    Pathology    and    Practice,    p. 

148. 
Basserbs.     Two  Cases  of  Sub-maxillary  Calculi. 

Revue    de   Stomatologie,    Dec.    1905;    abstriot, 

Dental  Cosmos,    1906,  Vol.  XLVIII,  p.   245. 
Black.     Operative  Dentistry,  Vol.  I,  p.  133. 
Bon.     Bulletin     de     V  Association     Otncrale     des 

Dentistes  de  Belgique ;  abstract.  Dental  Cosmos. 

1905,  Vol.  XLVII,  p.  146. 
Brown.     Occlusion    of    Stenson's    Duct    due    to 

Nipping  of  Orifice  by  Teeth.     Dental  Cosmos, 

1908,  Vol.  L,  pp.  2,  3. 
Bum.     Sialolithiasis.     Nos.  2  and  4  Oesterreichisch- 

Ungarische  Vierteljahrsschrijt  fur  Zahnheilkunde. 

Vienna,   1906;    abstract,  Dental  Cosmos,   1908, 

Vol.  L,  p.  886. 
Burchard.     Dental  Pathology  and  Therapeutics, 

2nd  ed.,  p.  533. 
Directions   for   making   Salivary   Analyses. 

Dental  Cosmos,  1909.  Vol.  LI,  p.  1093. 
Endelman.     Uratic  Iieposits  on  Roots  of  Teeth. 

De7ital  Cosmos,  1905.  Vol.  XLVII,  p.  935. 
Fenwick.     Lancet,  1877,  Vol.  II,  p.  303. 
Head.     Tartar   Solvent.     Dental   Cosmos,    1909, 

Vol.  LI,  p.  41. 
Hecht.     The  Prophylactic  Treatment  of   Caries. 

Dental  Cosmos,  1909,  Vol.  LI,  p.   1275. 
Howe.     Indicators  in  Salivary  Analysis  (Acidity 

and    Alkalinity).     Dental    Cosmos,     1911,    Vol. 

LIII,  p.  321. 
Howe.     Devices  and  volumetric  tests  for  Salivary 

Analyses.     Dental  Cosmos,    1912,  Vol.  LIV,  p. 

429. 
Johnson,   R.   H.     Sialolitliiasis   and   Abscess  of 

Wharton's    Duct.       Jour.    Atner.    Med.    Asso., 

May  30,    1908.     Dental   Cosmos,  1908,  Vol.  L, 

p.  885. 
JousSEAUME.     Calculi    in    Wharton's    Duct    and 

Sub-maxillary  Clland,  Revue  Odontologique,  Oct. 

1903;    abstract,     Dental     Cosmos,     1901,     Vol. 

XLVI,   p.  70. 
Kirk.     Susceptibility  and  Immunity  to    Dental 

Caries.     Dental  Cosmos,  1910,  Vol.  LII,  p.  729. 
Kirk.     Dental  Cosmos,  1905,  Vol.  XLVII,  p.  749. 
Kirk.     Dental  Cosmos,  1909,  Vol.  LI,  p.  793. 
Lanphear.     Parotid  Abscess  and  Calculi.     Amer. 

Jour,    of    Clin.    Med.,    June    1908;     abstract, 

Dental  Cosmos,  1908,  Vol.  L,  p.  885. 
Lauder    Brunton.      Address  at    Public  Health 

Congress,  Birkenhead,  1910. 
Le      Kov.       Calorimetric     Analysis    of    Sahva. 

Dental  Cosmos,  19(18.  Vol.  L,  p.  746. 
LocKWOOD.      Clinical    Journal,    July    17,    1907, 

p.  209. 
Marshall.      Operative    Dentistry,    3rd.    ed.,     p. 

539. 
Michaels.     Sialo-semeiology,      Transactions      of 

Third    International    Dental    Congress,    Paris, 

1902. 


255 


(26)  MiixER.     Immunity.     Dental  Cosmos,  1903.  Vol.        (29) 

XLV,    pp.    1,    85,    689;     1904,    Vol.    XLVI,    p. 
991. 

(27)  Perrone.     Salivary    Lithiasis    Requiring    Extir-  |    (30) 

pation  of  both  Sub-maxiUary  Glands.     Archiren  ! 

de    Stomatologic,    June    1904;   abstract,    Dental  I    (31) 

Cosmos,  1905,  Vol.  XLVII,  p.  519.  j 

(28)  Pierce.       International    Dental    Journal,     1894,  1 

p.  1.  !    (32) 


Report    of    Committee   of    Scientific  Research 

(Salivary  Analysis).     Dental  Cosmos,  1910,  Vol. 

LII,  p.  1234. 
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Cosmos,  1905,  Vol.  XLVII,  p.  519. 
Sherrington.     Note  on  Certain  Reflex  Actions 

connected    with    the    Mouth.     British    Denial 

Journal,  1910,  Vol.  XXX. 
Tomes.     Dental  Surgery. 


CHAPTER  XII 

THE   BACTERIA   OF  THE   MOUTH 


The  mouth  is  the  cavity  of  the  body  above 
all  others  most  suited  to  the  development  of 
bacteria.  Constant  exposure  to  all  forms  of 
infection,  both  aerial  and  dietetic,  allow  large 
numbers  of  bacterial  species  to  find  their  way 
into  the  oral  cavity,  and  at  first  glance  it  might 
be  supposed  that  the  bacterial  flora  of  the 
normal  mouth  was  not  only  an  ever-changing 
one,  but  one  without  any  fixed  characteristics. 

To  some  extent  this  is  true,  but  only  to  a 
limited  extent.  Environment  plays  a  con- 
siderable rule  in  determining  the  species  of 
bacteria  resident  in  the  mouth,  but  still  more  so 
does  the  question  of  food  supply  ;  for  the  species 
of  bacteria  present  in  any  given  situation  depend 
to  a  great  extent  upon  the  particular  variety 
of  bacterial  food-stuffs  available.  The  mouth, 
in  persons  exposed  to  different  forms  of  dusty 
materials  of  an  easily  fermentable  type,  as, 
for  instance,  in  persons  engaged  in  the  milling 
trade,  often  contains  an  excess  of  organisms 
that  ferment  carbo-hydrates,  particularly  yeasts 
and  various  members  of  the  lactic  acid  group ; 
and  this  special  flora  may  at  times  produce 
somewliat  rapid  caries. 

There  are  certain  physiological  considerations 
that  tend  to  lessen  the  numbers  and  species 
of  bacteria  residing  in  the  oral  cavity.  First 
and  foremost  of  these  is  the  mechanical  action 
of  mastication,  fibrous  food-stuifs  acting  most 
efficiently  in  removing  adherent  particles  of 
food  and  cleansing  the  surfaces  of  tlie  teeth 
and  cheeks,  and  thus  removing  the  material 
upon  which  bacteria  thi'ive  best.  Secondly, 
the  mechanical  action  of  the  saliva,  dissolving 
away  soluble  substances  and  (combined  with 
the  action  of  the  tongue  during  speech)  forcing 
saliva  between  the  teeth  and  around  the 
mouth,  assists  in  promoting  general  cleanliness. 
The  bacteria  are  washed  away,  and  swallowed 
and  dealt  with  by  the  normal  antiseptic  action 
of  the  stomach.  Further,  the  reaction  of  the 
oral  fluids  tends  to  inhibit  the  growth  of  a 
certain  number  of  bacteria  :  fresh  normal  saliva 
has  a  slight  inhibitory  action  on  the  develop- 
ment of  staphylococci,  though  this  inhibitory 
action  is  soon  lost  and  the  organisms  in  question 
develop  rapidly.  The  sulphocyanide  of  potash 
demonstrable  in  practically  all  normal  salivas, 
which  has  been  looked  upon  as  a  source  of 
destruction   of   organisms   in   the    mouth,   has 


only  a  slight  antiseptic  action ;  in  fact,  potassium 
sulphocyaiude,  added  to  broth  cultures  in 
proportions  fifty  times  greater  than  that  occur- 
ring in  normal  saliva,  has  no  inhibitory  action 
on  the  ordinary  organisms  found  in  the  mouth, 
although  it  is  possible  that  it  has  a  slight  re- 
straimng  action  on  the  growth  of  such  bacteria 
as  are  not  found  resident  in  the  buccal  secretions. 
One  other  point  of  considerable  importance, 
which  at  first  sight  appears  rather  paradoxical, 
is  the  occurrence  of  a  number  of  anaerobic 
organisms  in  pathological  lesions  affecting  the 
buccal  mucous  membrane,  gums,  and  teeth. 
As  the  mouth  is  open  to  the  air,  a  considerable 
supply  of  oxygen  is  available ;  it  is  somewhat 
strange,  therefore,  that  certain  septic  processes 
are  always  associated  with  the  gro«-th  of  obli- 
gatory anaerobic  species ;  yet  many  of  the 
anaerobes  to  be  found  in  the  mouth  are 
difficult  to  obtain  in  artificial  cultures  unless 
the  oxygen  in  the  medium  be  rigorously  ex- 
cluded by  freeing  the  medium  of  air  by  boiling, 
or  at  any  rate  heating,  to  60°  C.  for  some  time 
before  the  medium  is  used  for  cultivation.  If, 
however,  cultivations  are  made  from  the  mouth 
in  a  medium  saturated  with  carbonic  acid,  and 
also  if  impure  cultures,  such  as  an  ordinary  mixed 
culture  in  broth,  are  made  from  material  con- 
taining these  anaerobes,  particularly  in  the 
presence  of  a  large  amount  of  carbonic  acid, 
anaerobic  bacteria  grow  in  conjunction  with 
the  other  aerobic  organisms.  The  presence  of 
a  number  of  anaerobic  bacteria  in  the  mouth 
may,  perhaps,  be  attributable  to  the  high  per- 
centage of  carbonic  acid  present  in  the  saliva, 
and  also  to  the  absorption  of  free  oxygen  by 
the  growth  of  tlie  aerobic  bacteria,  in  much 
the  same  way  as  when  the  tetanus  bacillus  is 
cultivated  in  the  presence  of  bacillus  pyocyanus 
under  aerobic  conditions. 

The  acidity,  or  alkalinity,  of  the  saliva  con- 
stitutes a  considerable  factor  in  the  development 
of  the  mouth  bacteria,  and  the  writer  has  found 
by  prolonged  experiment  that  the  percentage 
of    alkali    required    for    the    development    of 
mouth   bacteria  is   a   degree   of  concentration 
represented  l)y  0-3  per  cent,  of  normal  sodium 
carbonate,  using  phenol-phthalein  as  indicator. 
It  follows  from  what  has  been  said  that  the 
I  ordinary  bacteria  of  the  air,  although  found  in 
'  the  mouth  from  time  to  time  as  adventitious 


256 


S' 


\ 


A 


•■4 


'or-- 

-I 

11 '      -;^  c 

r-e 

Fig.  380. 


A.  Streptococcus  pyogenes  {var.  longus),  24  lirs.  broth,  stained  Gram. 

B.  Staphylococcus  viscosus,  48  hrs.  agar,  stained  methyl  violet. 

C.  Micrococcus  catarrhalis,  24  hrs.  serum  agar,  stained  methyl  violet. 

D.  Bacillus  pyocyaneiis,  24  hrs.  agar,  stained  methylino  blue. 

E.  Bacillus  maximus  buccalis,  24  hrs.  agar,  stained  Gram. 

F.  Bacillus  necrodentalis,  24  hrs.  agar,  stained  Gram. 

These  figures  represent  a  magnification  of  a  little  more  than  TOO  diameters,  and 
have  been  reduced  from  the  writer's  photographs  of  1000  diameters. 


« 


258 


species,  do  not,  as  a  rule,  remain  as  normal 
inhabitants,  but  disappear  with  remarkable 
rapidity.  Thus  if  the  mouth  is  washed  out 
with  a  culture  of  bacillus  acidi  lactici  at 
night,  by  the  next  day,  at  any  rate  within 
twenty-four  hours,  the  number  of  bacteria 
of  this  species  is  so  small  that  it  is  chfficult  to 
obtain  cultures.  On  the  other  hand,  a  number 
of  bacteria  find  the  conditions  of  alkalinity, 
oxygenation,  etc.,  of  the  mouth  suited  to  their 
particular  requirements.  There  is,  therefore, 
an  indigenous  flora,  which  may  be  properly  cited 
as  true  mouth  bacteria,  inasmuch  as  they 
are  found  in  the  mouth  and  rarely  if  ever  in 
other  situations. 

A  study  of  the  Ijacteriology  of  the  mouth  is 
somewhat  complicated,  and  in  tlie  present 
chapter  no  attempt  is  made  to  deal  with  the 
ordinary  processes  in  use  in  bacteriological 
laboratories  for  tlie  isolation  and  identification 
of  the  various  species  of  bacteria,  nor  will 
the  routine  methods  in  use  for  bacteria  from 
various  pathological  sources  be  considered ;  for 
all  particulars  of  this  description  could  only 
be  epitomized  within  the  limits  available,  and 
such  epitome  is  of  no  value  whatever  for 
purposes  of  research,  and  would  only  be  con- 
fusing in  attempting  a  broad  general  sketch 
of  mouth  bacteria.  The  special  media  and 
processes  required  for  the  examination  of 
mouth  bacteria  will  be  found  in  the  writer's 
text-book  on  the  subject,  in  various  original 
papers  quoted,  and  also  in  the  larger  text-books 
dealing  with  general  bactei'iology. 

For  the  purpose  of  a  description  of  the  micro- 
organisms of  the  mouth  in  the  present  chapter 
the  usually  accepted  morpliological  divisions 
in  three  main  classes  ^^-ill  be  followed ;  these 
morphological  groups  are — 

Cocci, 

Bacilli, 

Spirilla. 

In  addition  to  these  groups  of  the  schizo- 
myccs,  or  fission  fungi,  certain  of  the  higher 
fungi  wiU  be  considered,  namely — 

Streptothricae, 

Blastomyces, 

Leptothricae. 

As  far  as  pos.sible  division  will  also  be  made 
under  each  heading  into  pathogenic  and  non- 
pathogenic ;  but  just  as  the  various  groups 
of  cocci  and  bacilli  tend  to  shade  into  one 
another,  .so  that  although  the  extreme  members 
of  any  given  group  are  dLstinet,  the  more  nearly 
related  are  difficult  to  differentiate,  so  also 
many  organisms  found  in  pathological  process 
in  the  oral  cavity  may  be  feebly  pathogenic  or 


fully  pathogenic,  or  may  possess  no  pathogenic 
properties  at  all  when  tested  on  the  usual  lab- 
oratory animals.  A  considerable  amount  of 
research  is  required  on  the  pathogenicity  of 
the  bacteria  of  the  mouth  before  many  vexed 
questions  can  be  settled. 

A  further  grouping,  \\hich  facilitates  the 
description  of  the  mouth  bacteria,  is  to  collect 
under  a  special  group  those  anaerobic  organisms 
tliat  are  known  to  occur  in  the  mouth. 

Sterilization 

Sterilization  of  the  mouth  is  practically 
impossible.  No  amount  of  mouth-washes, 
lotions,  syringing,  or  other  means,  can  ever 
render  the  human  mouth  sterile,  and  even 
after  the  most  careful  and  scrupulous  cleansing 
of  the  mouth,  organisms  \\ill  be  found  in  the 
shed  epitheUal  cells.  No  method  short  of 
removing  the  epitheUal  surface  of  the  mouth, 
gums,  and  tongue  will  ever  succeed  in  getting  rid 
of  all  the  bacteria  therein  contained.  All  that 
can  be  hoped  for  in  the  way  of  aseptic  pre- 
paration of  the  mouth  for  operations  is  to 
render  the  surfaces  free  from  deposits,  to  cut 
dowii  the  available  bacterial  food-stuffs  to  a 
minimum  by  mechanical  means,  and  then  to 
endeavour  to  inliibit  the  development  of  the 
bacteria  present  by  means  of  antiseptic  lotions ; 
for  it  must  be  remembered  that  the  first  mouth- 
ful of  ordinary  food,  taken  after  a  thorough 
attempt  at  sterilization  of  the  mouth  has  been 
made,  results  in  reinfection  of  the  whole  of  the 
surfaces. 

The  mechanical  clearing  away  of  deposits  in 
the  mouth  is  of  as  much  importance  as  the 
use  of  antiseptic  lotions,  but  this,  of  course,  in 
no  «ay  discredits  the  use  of  antiseptics  as  an 
adjunct  to  the  mechanical  procedure. 

In  all  operative  procedures  about  the  mouth, 
full  care  should  be  exercised  in  the  promotion 
of  cleanliness  in  the  ordinary  accepted  sense  of 
the  term,  as  well  as  in  its  bacteriological  sense. 
Wlien  immunization  has  been  carried  out  prior 
to  operative  procedure,  an  attempt  should  be 
made  to  promote  the  external  flow  of  lymph, 
and,  instead  of  coagulative  or  corrosive  sub- 
stances, demulcent  fluids  .should  be  used,  more 
particularly  normal  sodium  clilorido  contain- 
ing one  per  cent  of  sodium  citrate.  After  the 
flow  of  lymph  has  ceased  and  the  surfaces  of 
the  operation  wound  are  partially  healed,  the 
use  of  antiseptic  lavage,  either  formalin  1  in 
4000  with  \  %  glycerine,  or  tricresol  1  in  500, 
or  other  antiseptic,  is  desirable  ;  but  the  most 
efficient  mouth-lotion  is  an  antiseptic  such  as 
carbolic  acid  acidulated  with  lactic  acid  0'25 
per  cent. 

The  sterUization  of  dental  instruments  is  a 
matter  that  requires  a  considerable  amount  of 


259 


care,  more  especially  as  a  number  of  siicli 
instruments  are  exceedingly  delicate  and  easily 
damaged  by  boiling  water,  etc.  For  forceps, 
elevators,  and  other  surgical  instruments,  boil- 
ing for  three  or  four  minutes  in  water  with 
1  %  sodium  carbonate  is  the  best,  as  practically 
no  spore-forming  bacteria  are  to  be  found  in 
the  mouth,  and  if  due  care  is  taken  with 
instruments  in  the  way  of  common  cleanliness,  j 
no  j)athogemc  sporulating  organisms  should  | 
come  in  contact  with  them. 

Scaling  instruments,  and  those  used  for  the 
treatment  of  root-canals,  require  efficient  steri- 
lization. Not  a  few  of  the  failures  in  treating 
so-called  "dead  "  teeth,  as  well  as  the  spread 
of  alveolar  infection,  are  to  be  attributed  to 
the  use  of  unsterilized  instruments,  one  patient 
becoming  infected  from  another.  Scaling  in- 
struments should  be  treated  as  forceps,  etc., 
whilst  burrs,  fine  bristles,  and  so  forth,  should 
be  first  thoroughly  cleaned  from  any  adheiing 
material,  and  then  boiled  in  liquid  paraffin 
and  put  away  in  a  sterile  tube  of  paraffin  to  pre- 
vent any  possibility  of  rusting.  Soaking  in 
absolute  alcohol  for  twenty-four  hours  is  also 
an  efficient  method,  and  the  alcohol  may  be 
tlamed  off  the  instrument  before  use. 

Instruments  frequently  omitted  from  the  list 
of  those  particularly  requiring  sterilization  are 
clamps  and  separating  apparatus.  It  should 
be  laid  down  as  a  general  rule  that  all  dental 
instruments,  and  above  all,  those  that  come 
in  contact  with  the  soft  tissues,  should  be 
efficiently  sterilized  by  boiling  every  time  they 
are  used. 

GROUP    I— COCCI 

The  group  of  cocci  comprises  a  large  number 
of  different  morphological  forms. 

A  coccus  is  defined  as  a  uni-cellular  organism 
reproducing  itself  by  binary  fission,  and  having 
its  greater  diameter  not  more  than  twice  the 
lesser.  They  are  round,  pear-shaped,  or  oval 
bodies,  not  possessed  of  flagellae,  and  therefore 
non-motile,  and  are  divided  into  groups  Ijy  the 
arrangement  of  the  cells  resulting  from  the 
method  of  division. 

It  must  bo  understood,  however,  that  division 
of  the  organisms  may  take  place  so  rapidly 
that  they  may  remain  attached  to  one  another 
by  a  species  of  capsule,  which  in  some  instances, 
as  in  the  diplococcus  pneumoniae,  is  stainable 
by  certain  special  means.  Groups  of  the  cocci 
merge  into  one  another  insensibly,  and  the 
particular  t\^e  to  which  a  given  organism  is 
allocated  is  only  the  typical  formation,  many 
variations  of  which  may  always  be  discovered 
in  films  made  from  one  and  tlie  same  cultivation. 

The  cocci  are  divided  into  the  following 
groups — 


(1)  Micrococci  :  the  arrangement  of  the  cocci 

is  irregular,  and  the  organisms  for  the 
most  part  remain  isolated. 

(2)  Diplococci :    the    cocci    are    arranged    in 

pairs. 

(3)  Staphylococci  :  the  cocci  are  arranged  in 

irregular  clusters. 

(4)  Streptococci  :  the   cocci   are   arranged  in 

chains  of  three  or  more  members, 
sometimes  extending  up  to  several 
hundred. 

(5)  Tetracocci  :  the  organisms  are  of  the  coccal 

type  and  arranged  in  groups  of  four, 
division  having  taken  place  in  two 
planes  at  right  angles  to  one  another, 
whereas  in  the  first  four  groups  the 
division  is  in  various  directions  but 
always  in  the  same  plane. 

(6)  Sarcinae  :   division   of   the  organisms  in 

this  group  is  in  three  planes  at  right 
angles  to  one  another,  the  resulting 
form  being  that  of  ii-regular  cubes. 

Owing  to  the  merging  into  one  another  of 
the  coccal  groups — diplococci,  staphylococci, 
as  well  as  tetracocci — some  ^Miters,  amongst 
whom  may  be  cited  Lehmann  and  Neumann, 
have  used  the  term  "  Micrococcus  Pyogenes  " 
to  denote  the  whole  of  the  coccal  group, 
and  although  a  number  of  the  organisms  are 
non-pathogenic,  there  is  some  reason,  onmorpho- 
logical  grounds  alone,  for  placing  the  whole  of 
the  coccal  series  into  one  group.  The  organ- 
isms, however,  will  be  considered  here  according 
to  the  six  morphological  groupings  given  above. 

Pathogenic  Cocci 

Micrococcal  Group. — The  chief  of  the  patho- 
genic organisms  amongst  the  micrococcal  group 
that  may  be  regarded  as  a  mouth  organism  is 
the  Micrococcus  Catarrhalis.  Tliis  organism  is 
found  as  isolated  cocci,  or  as  diplococci.  The 
size  of  the  organism  varies  considerably — from 
0-5  to  l-5ju,.  The  typical  micrococcus  catarrhalis. 
when  gro\\'n  on  the  usual  laboratory  test  media, 
produces  no  fermentation  of  carbo-hydrates 
with  the  rare  exception  of  glucose.  It  is  a  Gram- 
negative  organism,  but  stains  w  itii  the  usual  ani- 
line dyes.  The  growth  on  t  lie  surface  of  agar  is 
rather  adherent  and  gelatinoid.  The  organism 
requires  an  alkalinity  corresponding  to  that  of 
the  saliva,  while  its  growth  is  furthered  by 
the  addition  of  serum  or  egg  albumen  to  the 
medium,  but  ordinary  agar,  +  3  alkaUnity,  is  a 
perfectly  satisfactory  medium  for  its  growth. 

The  micrococcus  catarrhalis  is  the  cliief 
representative  of  the  Gram-negative  cocci  met 
with  in  the  mouth,  but  a  large  number  of  other 
Gram-negative  cocci  arc  from  time  to  time  found 
in  the  l)uccal  secretions,  and  are  conveniently 


260 


placed  under  the  general  heading  of  the  micro- 
coccus  catarrhalis   group,    notwitlistanding    the 
fact  that  a  number  of  them  produce  definite 
fermentation    of    carbo-hydrates.     Much    con- 
troversy   still    rages    as    to   tlie    efficiency    of 
carbo-hydrate  fermentation  m  the  differentiation 
of  various  liacterial  groups ;  so  that  this  general 
grouphig  of  Gram-negative  cocci  of  the  mouth, 
fermenting    carbo-hydrates   feebly   or    not    at 
all,  may  be  retained  pro\-isionaUy.    The  organ- 
ism is  not  pathogenic  in  ordinary  circumstances 
for    the    lower    animals,    but    it    occurs    very 
commonly  in   the   common    "cold"  or  coryza 
of   the    nasal    passages,   and    has    been   found 
in    many    cases     as    the    cause    of   post-nasal 
discharges  and  chronic    posterior  rhinitis,  and 
may   even   cause    acute    broncliitis.     Although 
it    is    feebly    pathogenic    for    animals,     killed 
cultures  of  the  organism,  when  inoculated  into 
persons  susceptible  to  "catching  cold",  usually 
produce    symptoms    of    acute    nasal    catarrh, 
together  with  the  pains  in  the  limbs  and  joints 
often  associated  with  an  influenzal  cold.     The 
direct  experiment  of  inoculating  a  susceptible 
animal   (man)  with   this  organism,  presumably 
the    cause    of    the   disease,    results   in   definite 
symptoms  of  the  disease,  although  the  material 
used  for    inoculation    has    been   sterilized    by 
heat,   that   is   to  say,  only   dead  bacteria  and 
their  extracts  are  made  use  of.     Considerable 
proof  is  thereby  furnished  of  the  relationship 
of  this  particular  coccus  to  acute  coryza. 

The  micrococcus  catarrhalis  is  often  found  in 
symbiosis  with  other  organisms  along  the 
alveolar  margins  in  cases  of  alveolar  pyorrhoea  ; 
and  on  several  occasions  the  writer  has  demon- 
strated the  presence  of  this  organism  in  the 
urine  of  persons  whose  mouths  were  infected 
with  it.  It  may  be  regarded  as  one  of  the 
important  factors  in  mixed  infections  of  the 
alveolar  process,  and  particularly  in  those 
associated  with  post-nasal  catarrh ;  and  the 
use  of  an  autogenous  vaccine  jjroduced  from 
the  organism  is  frequently  indicated  in  mouth 
infections. 

Micrococcus  Gonorrhoea. — This  organism, 
closely  related  to  the  micrococcus  catarrhalis, 
has  been  occasionally  described  as  occurring 
in  the  mouth.  The  organism  is  a  diplococous, 
generally  arranged  as  pairs,  the  cocci  being 
somewhat  flattened  towards  their  base,  and 
having  the  flattened  l)ase  turned  towards  one 
another.  The  organism  is  typically  found  in  the 
pus  cells  in  the  urethral  discharge  in  gonorrhoea  ; 
it  grows  with  considerable  difficulty  on  the  sur- 
face of  agar  unless  the  jiercentage  of  alkalinity  is 
carefully  adjusted  (46) ;  on  the  other  hand,  agar 
smeared  with  fiesh  blood  allows  the  organism 
to  grow  fairly  rapidly,  but  it  very  soon  dies 
out.  Its  occurrence  in  the  mouth  is  extremely 
rare,   and  the    writer  himself    has   never  met 


with  it  in  over  six  thousand  cases  examined 
bacteriologically,  but  it  is  possible  that  in  cases 
of  gonorrhoeal  conjunctivitis  the  organism  might 
gain  access  to  the  mouth. 

Diplococous  Inlracellularis,  or  Micrococcus 
Intracellularis. — This  Gram-negative  coccus  is 
closely  related  to  the  preceding  in  its  morpho- 
logical and  cultural  reactions.  The  growth 
is  still  more  delicate  than  the  gonococcus 
and  dies  out  in  two  or  three  days.  The 
organism  is  typically  found  in  the  cerebro- 
spinal fluid  in  cases  of  acute  cerebro-spinal 
meningitis,  and  was  first  described  by  Weichel- 
baum.  It  is  occasionally  to  be  found  in  the 
mouth,  but  more  commonly  in  the  nose, 
where  it  may  remain  as  a  saprophyte.  At 
the  same  time  the  close  relationship)  of  the 
bacterial  flora  of  the  nose  and  mouth  must  not 
be  forgotten.  Most  of  the  mouth  bacteria  are  to 
be  found  both  in  the  maxillary  sinus  and  in 
the  nasal  passages  from  time  to  time,  and  the 
close  proximity  of  the  nose  to  the  cerebro- 
spinal system  via  the  cribriform  plate  of  the 
ethmoid  is  sufficiently  close  to  suggest,  if  no 
more,  a  possible  source  of  infection  via  the 
nose  and  mouth.  In  the  cerebro-spinal  fluid 
the  micrococcus  intracellularis  is  found  in  the 
interior  of  the  jjolymorpho-nuclear  leucocytes. 

Micrococcus  Tetragenous.  —  This  organism 
grows  as  small  medium  cocci,  0'5-0'75/x,  arranged 
typically  in  groups  of  four,  but,  as  a  rule,  only 
occurring  in  the  tetrad  grouping  in  the  Ijodies 
of  infected  animals,  especially  in  animals  in- 
oculated with  a  pure  culture  of  the  organism. 
The  organism  frequently  occurs  in  the  mouth, 
and  was  first  described  in  association  with  the 
tubercle  bacillus  in  the  cavities  of  tuberculous 
lungs. 

On  many  occasions  the  tetracoccal  form  may 
be  found  in  members  of  the  staphylococcal 
group,  but  the  organism  known  as  the  micro- 
coccus tetragenous  differs  from  the  staphylococcal 
grouping  and  growth.  It  stains  by  Gram's 
method,  although  by  no  means  as  deeply  as 
many  of  the  other  cocci,  but  it  may  be  dis- 
tinguished from  the  tetrad  groujDS  of  the 
meningococcus  by  its  behaviour  towards  Gram's 
stain.  It  grows  very  well  on  the  ordinary 
laboratory  media,  and  does  not  liquefy  gelatin. 
Wlien  inoculated  into  white  mice  it  is  ex- 
ceedingly pathogenic,  and  is  found  in  typical 
form  of  tetracocci  in  the  spleen,  liver,  kidneys, 
and  blood.  In  guinea-pigs  it  oidy  forms  a 
local  abscess.  Li  man  it  may  cause  localized 
suppuration  along  the  gum  margins. 

An  irregular  form  of  micrococcus  tetragenous 
has  been  described  by  several  observers  as 
occurring  in  the  mouth,  under  the  name  of 
priratelragenous.  A  certain  number  of  these 
organisms,  from  the  descriptions  given,  \\ould 
appear  to  be  staphylococcus  albus,  and  others 


261 


are  probably  the  true  micrococcus  tetragenous. 
The  micrococcus  tetragenous  requires  to  be 
differentiated  from  the  sarcinae,  particuhirly 
the  snuill  form  of  the  sarcina  alba  often  found 
in  the  buccal  secretions. 

Staphylococcal  Group. — These  organisms 
occur  in  clusters  and  masses,  0'75-rO  /x,  and 
are  termed  staphylococcal  from  their  fancied 
resemblance  to  bundles  of  grapes.  In  cultures 
the  typical  form  is  the  stajjhylococcal  form, 
whereas  in  pus,  and  in  the  Ijlood  in  acute  in- 
fections, the  staphylococcal  form  is  rare. 
Diplococci  or  isolated  cocci  are  usual.  On 
broth  cultures  the  morjshology  tends  somewhat 
towards  the  streptococcal  form,  and  chains 
are  frequently  met  with,  but  it  is  on  the  surface 
of  solid  media,  such  as  agar,  potato,  and  gelatin, 


^ 


.^r^,."^ 


K.^ . 


Fig.  381. — Staphylococcus  aureus,  24  hrs.  agar, 
Gram,      x  1000. 

that   the  typical    staphylococcal    form    is    best 
seen. 

The  staphylococcal  group  is  divided  into 
various  sub-species  according  to  the  production 
of  pigment ;  the  three  chief  forms  are — 

(«.)  StapltyJococcus  Aureus,  or  golden  staphylo- 
coccus, which  produces  a  well-marked  orange- 
yellow  pigment,  and  differs  from  many  other 
chromogenic  bacteria  by  producing  pigment 
at  the  temperature  of  the  hot  incubator,  37°  C, 
namely,  blood  heat.  Liijucfaction  of  gelatin  is 
ra])id. 

[h]  Stajihylococcus  Albus,  which  produces  no 
pigment,  but  forms  a  glistening  or  dull  porce- 
lainous  growth  on  agar,  and  liquefies  gelatin 
very  slowly. 

(f)  Staphylococcus  Citreus,  which  produces 
pigment  of  a  lemon-yellow  colour.     The  growth 


is,  as  a  rule,  more  luxuriant  than  that  of  either 
of  the  preceding  two.  Liquefaction  of  gelatin 
is  usually  rapid. 

Morphologically,  little  or  no  difference  exists 
between  the  three  types  of  staphylococci,  but 
as  a  general  rule  the  more  lu.xuriantly  growing 
form  of  the  staphylococcus  has  the  larger  type 
of  coccus,  and  the  more  virulent  the  organism 
the  smaller  are  the  individual  cocci.  Usually, 
the  staphylococcus  aureus  forms  smaller  in- 
dividual cocci  than  either  the  albus  or  citreus. 

In  addition  to  these  three  typical  forms  of 
staphylococci  a  number  of  gradations  may  be 
found  merging  from  one  group  to  the  other. 
The  staphylococcus  aureus  is  by  no  means  a 
constant  inhabitant  of  the  mouth,  and  in  the 
records  of  over  three  thousand  of  the  writer's 
cases  the  organism  only  occurs  in  15  per  cent, 
a  figure  agreeing  with  other  observers.  It  is 
rare  in  supjjurative  processes  along  the  gum 
margins,  but  when  found  it  may  be  regarded 
as  the  infecting  organism,  as  distinguished  from 
a  number  of  other  saprophytic  forms,  which 
may  be  present  at  the  same  time. 

The  more  common  staphylococcus  in  the 
mouth  is  the  staphylococcus  albus ;  this  organ- 
ism only  occurred  in  about  25  per  cent  of  the 
cases  examined.  The  colour  produced  by  the 
staphylococci  most  commonly  found  in  cultures 
from  the  jaws  is  midway  between  that  of 
staphylococcus  aureus  and  albus,  and  is  dirty- 
brownish  to  grey.  Moreover,  the  staphylococci 
obtained  direct  from  the  mouth  do  not,  as  a  rule, 
exhibit  the  same  rapidity  of  gelatin  liquefaction 
as  do  the  staphylococci  oljtained  from  superficial 
skin  infections,  boils,  carbuncles,  or  other  infec- 
tive processes  with  which  the  staphylococcus 
is  so  commonly  associated. 

The  staphylococci  stain  readily  by  Gram's 
method,  and  with  the  usual  aniline  dyes ;  they 
produce  very  considerable  fermentation  of 
carbo-hydrate  media,  although  the  fermenta- 
tion of  the  carbo-hydrates  differs  considerably 
in  individual  ca.ses.  Of  the  staphylococci 
described  in  the  writer's  Erasmus  Wilson 
lecture  (21),  a  number  were  tested  in  various 
carbo-hydrate  media ;  in  most  instances  the 
staphylococcus  aureus,  with  well-marked  orange 
pigment,  was  the  most  active  in  the  fermenta- 
tion tests,  giving  an  acid  production  with  six 
carbo-hydrates,  namely,  glucose,  lactose,  mal- 
tose, cane  sugar,  inulin,  and  manitol.  On  the 
other  hand,  the  staphylococcus  albus  and  the 
ill-defined  group  between  the  aureus  and  the 
aliius  were  more  uncertain  in  their  fermenta- 
tion. Further,  if  an  ordinary  staphylococcus 
albus  is  grow  n  for  a  time  under  anaerobic  condi- 
tions, the  power  of  liquefaction  of  gelatin  is 
very  considerably  impaired,  and  may  become 
altogether  lost. 


262 


The  pathogenicity  of  the  staphylococci  is  ' 
well  known.  Tliey  are  to  be  found,  as  lias  been 
stated  above,  in  acne  pustules,  skin  eruptions 
of  various  types,  boils,  carl)uncles  and  abscesses, 
and  in  osteitis,  osteomyelitis,  and  acute  infective 
periostitis.  From  these  situations  they  may 
gain  access  to  the  blood-stream,  and  they  are 
also  often  found  in  cases  of  leptomeningitis 
and  other  diseases  of  the  brain.  They  are 
facultative  anaerobic. 

The  virulence  of  the  staphylococci  for  the 
lower  animals  varies  a  good  deal,  but  they  are 
typically  pathogenic  for  rabbits,  and  produce 
abscesses  in  the  cortex  of  the  kidney  \\lien 
injected  subcutaneously  or  intra-peritoneally. 

The  staphylococcus  group  does  not  produce 
any  special  toxin,  \\hich  may  be  differentiated 
according  to  the  particular  type  of  staphylo- 
coccus, and  attemjits  to  produce  an  antitoxic 
serum  for  the  treatment  of  staphylococcal  cases  i 
have  not  met  with  any  degree  of  success.  On 
the  other  hand,  vaccines  prepared  by  heating 
an  emulsion  of  staphylococci  in  normal  saline 
to  58°  C.  for  half  an  hour  have  proved  effica- 
cious in  the  treatment  of  acute  and  chronic 
staphylococcal  infections.  The  vaccine  is  pre- 
pared in  the  following  manner. 

Tlie  staphylococcus  is  gro\\ii  for  twenty-four 
hours  on  the  surface  of  agar,  the  culture  is  then 
washed  off  with  a  minimal  quantity  of  sterile 
normal  saline  solution  under  strict  aseptic  pre- 
cautions, and  the  emulsion  of  cocci  placed  in  a 
mechanical  shaker  and  shaken  for  some  ten  ! 
minutes  until  an  even  suspension  is  produced,  i 
The  number  of  organisms  per  cubic  centimetre 
is  then  estimated  in  an  aliquot  portion  of  the 
emulsion,  and  the  bulk  of  the  emulsion  sub- 
mitted to  a  temperature  of  58°  C.  for  half  to 
three-quarters  of  an  hour.  The  heated  emul- 
sion, or  vaccine,  is  then  tested  for  sterility  by 
making  cultures  upon  agar  tubes  and  incubating 
for  forty-eight  hours.  The  emulsion  having 
been  proved  sterile,  it  is  diluted  with  normal 
saline  solution  containing  -25  %  tricresol  to 
an  appropriate  strength,  the  content  of  the 
finished  vaccine  varying  from  50  to  500  millions 
per  cubic  centimetre.  The  vaccine  is  then 
distributed  in  a  number  of  small  bulbs  and 
used  for  inoculation.  The  preliminary  dose  of 
vaccine  injected  should  always  be  a  minimal 
one,  and  the  appearance  of  negative-phase 
sjonptoms  carefully  watched  for.  This  method 
of  vaccine  preparation,  with  slight  modifications, 
is  that  in  use  for  the  production  of  vaccines  for 
all  sorts  of  bacteria  in  vaccine  therapy.  For 
fuller  information  with  regard  to  the  maimfac- 
ture  of  vaccines  and  the  general  technique  of 
vaccine  therapy  the  student  is  referred  to  various 
original  papers  on  the  subject  (9). 

The  diagnosis  of  the  staphylococci  presents 
little  difficulty.     The  pus  from  an  ab.scess  or 


carbuncle  containing  staphylococci  is  found  to 
be  teeming  with  cocci,  mostly  as  diplococci,  but 
often  as  tetracocci.  Numerous  cocci  are  also 
found  in  the  leucocytes,  staining  readily  by 
Gram's  method.  Cultures  are  made  direct 
upon  one  of  the  usual  laboratory  media,  pre- 
ferably agar,  and,  if  necessary,  the  culture  is 
plated  at  the  end  of  twenty-four  hours,  when 
the  typical  colonies  may  be  easily  isolated,  and 
the  required  sub-cultuies  made. 

The  Staphylococcus  Citreus  is  not  often  present 
in  the  mouth,  but  is  more  commoiJy  found  in 
the  air.  It  may  be  occasionally  found  con- 
taminating plate  cultures  made  from  the 
mouth  direct,  and  its  origin  from  the  air  should 
always  be  suspected.  It  may,  however,  be 
occasionally  met  with  as  a  mouth  inhabitant. 

Non-Pathogenic  Cocci 

A  form  of  staphylococcus  that  occurs  in  the 
mouth,  but  is  only  feebly  pathogenic,  is  an 
organism  described  in  the  first  place  by  Freund 
(20).  Tills  organism  resembles  in  many  re- 
spects the  staphylococcus  citreus,  but  differs 
from  that  organism  in  its  behaviour  towards 
Gram's  stain,  being  Gram-negative.  It  is 
named  by  Freund  micrococcus  citreus  granulatus, 
largely  because  of  the  colonies  and  the  growth 
upon  agar.  It  is  distinguishable  from  the 
ordinary  staphylococci  found  in  the  mouth 
by  the  colour,  often  almost  sulphur-yellow, 
by  its  Gram-negative  staining,  and  by  the  fact 
that  it  does  not  produce  fermentation  of  carbo- 
hydrates. It  occasionally  produces  small  local- 
ized abscesses  when  inoculated  into  mice,  but 
has  not  produced  pathogenic  effects  on  rabbits 
and  guinea-pigs  in  the  writer's  hands.  It  may 
be  regarded  as  non-pathogenic. 

Staphylococcus  Viscosus. — This  is  another 
Gram-negative  organism,  which  in  some  ways 
resembles  the  staphylococci,  and  is  met  with 
in  the  human  mouth,  and  may  also  be  found 
in  the  nose  and  tonsils.  In  some  ways  it  is 
closely  related  to  the  micrococcus  catarrhalis, 
but  differs  from  that  organism  in  the  peculiar 
form  of  its  colonies,  and  in  the  fact  that 
these  colonies  are  gelatinous  in  consistency, 
being  extremely  hard  to  remove  from  the 
surface  of  the  medium  upon  which  they  are 
growing,  and,  when  lifted  with  a  platinum 
spatula,  coming  away  entire.  The  organism  is 
difficult  to  stain,  as  it  is  surrounded  by  a 
gelatinous  capsule ;  the  typical  forms  are  found 
in  agglomerated  masses,  and  more  rarely  as 
tetracocci.  The  organism  does  not  ferment 
the  usual  carbo-hydrate  media,  but  produces 
considerable  fermentation  of  nitrate  broth, 
giving  a  nitrite  reaction,  often  within  six  or 
seven  hours,  when  tested  with  sulphuric  acid 
solution  of  meta-phenyl-amine-diamine. 


263 


The  organism  is  of  considerable  importance 
in  the  early  stages  of  dental  caries,  more  espe- 
cially as  it  grows  in  active  symbiosis  witii  a 
number  of  other  mouth  bacteria;  its  ciiiiously 
adherent  colonies,  which  may  often  be  seen 
in  the  nitrate  broth  cultures  adhering  to  the 
sides  of  the  test-tube,  most  probably  act  as 
one  of  the  predisposing  causes  in  the  early  ) 
stages  of  dental  caries,  producing  adherent  \ 
patches  on  the  enamel  surfaces.  The  writer 
has  succeeded  in  producmg  these  ]>laques  arti- 
ficially upon  whole  teeth  suspended  in  cultures 
of  the  organism,  and  found  also  that  active 
symbosis  takes  place  with  many  acid-producing 
organisms;  its  role  in  dental  caries  is  thus 
evident. 

In  its  cultural  characters  the  organism  some- 
what jesembles  the  micrococcus  catarrhalis, 
but  it  grows  with  difficulty  both  on  broth 
and  milk,  and  does  not  grow  on  gelatin.  It 
does  not  grow  below  the  ordinary  incubator 
temperature,  37°  C. 

Sarcinae. — The  group  of  sarcinae  form  the 
lowest  scale  of  the  cocci  with  regard  to  patho- 
genicity. With  one  or  two  exceptions,  they 
are  not  found  causmg  suppuration.  Tlie  sar- 
cinae are  fairly  active  fermenters  of  carbo- 
hydrates, and,  as  they  occur  with  considerable 
regularity  in  the  mouths  of  persons  suffer- 
ing from  dental  caries,  and  are  found  in  the 
cavities  of  carious  teeth  with  great  frequency, 
they  may  be  certainly  regarded  as  organisms 
associated  with  the  destruction  of  the  teeth. 
Furthermore,  the  majority  of  the  sarcinae  are 
organisms  producing  proteolytic  enzymes,  and 
although  they  do  not  liquefy  blood  serum, 
they  are  still  capable  of  digesting  decalcified 
dentine. 

Typical  sarcinae  are  organisms  occurring  in 
packets  of  eight,  this  form  being  produced  by 
their  method  of  divi.sion  in  three  planes  at 
right  angles  to  one  another ;  but  in  the  ordinary 
smear  preparations  made  from  cultures  the 
typical  sarcinal  form  is  not  preserved,  the 
small  packets  becoming  broken  up  in  making  the 
films.  To  obtain  a  proper  idea  of  the  typical 
sarcinal  form,  recourse  must  be  had  to  the 
method  of  the  hanging -drop  preparation,  when 
beautiful  packets  of  cocci  arranged  symmetri- 
cally in  small  cubes  can  be  seen. 

Like  the  closely  allied  staphylococci,  the 
sarcinae  are  pigment-producers.  Three  well- 
known  varieties  of  pigment-producing  sarcinae 
are  recognized — 

(a)  Sarcina  Aurantiaca,  producing  an  orange 
pigment. 

(6)  ^'arc!M«  Z,w7ca,  producing  a  yellowish  pig- 
ment. 

(c)  Sarcina  Rosa,  producing  a  rose-pink  pig- 
ment. 


In  addition,  Sarcina  Alba,  with  a  colourless, 
or  whitish  porcelainous  growth,  is  also  common. 

Like  the  nearly  allied  staphylococci,  the 
sarcinae  vary  very  considerably  in  the  size  of  the 
individual  cocci.  Ordinarily,  the  .sarcina  lutea 
is  the  largest,  the  aurantiaca  holds  an  inter- 
mediate position,  and  the  alha  is  usually  the 
smallest.  The  sarcina  aurantiaca  is  not  so 
common  in  the  mouth  as  the  sarcina  lutea,  while 
the  most  commonly  occurring  form  of  the  three 
is  the  sarcina  alba.  This  is  a  small  sarcina, 
and  the  growth  closely  resembles  the  granular 
appearance  of  the  saccharomyces.  All  the 
sarcinae  grow  readily  on  gelatin,  with  the 
exception  of  the  peculiar  sarcina  alba  found 
in  the  mouth.  The  sarcina  lutea  and  sarcina 
aurantiaca  produce  their  pigment  only  at  the 
room  temperature,  and  not  at  the  temperature 
of  the  body.  The  most  typical  colour  is  pro- 
duced on  the  surface  of  boiled  potato.  Gelatin 
is,  as  already  stated,  rapidly  liquefied,  and  the 
growth  on  broth  is  heavy,  the  whole  of  the 
fluid  being  rendered  turbid,  and  a  thick  deposit 
produced ;  at  20°  C.  tliis  deposit  is  often  pig- 
mented. 

The  inocidation  of  considerable  quantities 
of  these  sarcinae  into  animals,  such  as  rabbits 
and  guinea-pigs,  produces  no  fatal  result. 
Sarcinae  may  be  found  in  acne  pustules. 

The  colonies  of  the  sarcinae  are,  as  a  rule,  large, 
and  often  marked  with  a  central  projection, 
the  surface  being  smo  and  glistening.  Little 
or  no  chflficulty  is  expa  -need  in  isolating  these 
organisms  owing  to  t  j  large  size  of  their 
colonies  and  their  rapid  growth,  and  their 
typical   morphology. 

Streptococcal  Group. — The  group  of  strepto- 
cocci comprises  a  large  number  of  diverse 
bacteria,  many  of  them  highly  pathogenic 
both  for  man  and  the  lower  animals,  as  well 
as  a  number  that  are  simple  saprophytes, 
and  are  to  be  found  widely  distributed  in 
Nature. 

The  first  description  of  the  streptococci  was 
made  by  Billroth  in  1874,  when  he  described 
the  organism  as  a  "cocci  bacteria  septica ". 
From  this  time  onwards  much  attention  was 
paid  to  the  bacteriology  of  wounds  and  septic 
processes,  and  Fehleisen  (17)  and  Rosenbach 
(36),  by  the  use  of  pure  cultures,  demonstrated 
the  pathogenicity  of  the.se  chain-forming 
organisms. 

The  streptococcus,  as  its  name  implies,  is  an 
organism  growing  in  a  chain,  'i'ho  mor})hology, 
however,  shows  considera))le  variation  :  isolated 
cocci  may  be  found,  or  short  chains  of  only 
three  or  more  elements;  at  other  times,  inter- 
spersed throughout  the  chahi,  are  to  be  found 
elongated  forms  closely  resembling  bacilli, 
the  chain  having  the  appearance  of  a  sentence 
in  Morse  code.     On  the  other  hand,  scattered 


264 


throughout  the  chain  may  be  swollen  and 
irregular  forms,  oval  or  elliptical,  sometimes 
described  as  arthrospores,  a  moditied  and  more 
resistant  form  of  the  organism ;  this  view  is 
doubted  by  other  observers,  who  regard  these 
swollen  elements  in  the  chain  as  being  merely 
involution  forms. 

On  the  surface  of  agar  and  on  other  solid 
media,  the  organism  may  closely  resemlile  the 
staphylococcus,  the  cocci  being  arranged  in 
masses  with  very  Uttle  sign  of  chain  formation. 
But  the  typical  form  is  in  chains,  best  seen  upon 
liquid  media,  the  organisms  growing  out  to  their 
maximum  length  in  fluids. 

In  many  races  of  streptococci  the  individual 
chains  show  special  characteristics.  Occasion- 
ally, chains  of  diplococci  are  to  be  seen ;  some- 
times tangled  masses,  with  a  number  of  swollen 
forms  as  well,  and  to  this  particular  type  the 
term  Streptococcus  Conglomeratus  has  been 
given. 

Some  varieties  of  streptococci  have  been 
recognized  as  associated  with  special  diseases, 
and  as  having  cultural  characters  sufficiently 
well  marked  to  separate  oE  the  given  strepto- 
coccus into  a  sub-species.  The  most  typical 
form  of  streptococcus  differentiated  in  this 
manner  is  the  streptococcus — or,  as  it  is  most 
often  termed,  the  diplococcus — pneumoniae. 

The  Diplococcus  Pneumoniae  was  first  de- 
scribed by  Frankel  (19).  Previously,  the  diplo- 
bacillus  of  Friedlander,  which  had  been  described 
as  occurring  constantly  in  pneumonic  aiTections, 
was  regarded  as  the  cause  of  pneumonia ;  but 
Frankel  showed  by  animal  experiments  that 
although  the  Friedlander  bacillus,  or  bacillus 
pneumoniae,  may  be  often  found  in  pneumococcal 
affections,  the  diplococcus  pneumoniae  was  really 
the  exciting  cause  of  the  disease.  The  organism 
occurs  typically  in  pneumonia  as  diplococci, 
pear-shaped  in  form,  with  the  broader  bases 
turned  towards  one  another,  and  the  whole 
diplococcus  surrounded  by  a  gelatinous  capsule, 
which  only  stains  by  sjDecial  methods.  The 
capsule  is  not  formed  on  ordinary  laboratory 
media,  but  may  occasionally  be  found  in  gelatin 
cultures  grown  in  the  hot  incubator,  and  also 
on  serum  cultures — water  of  Hiss, — particularly 
milk  to  which  serum  has  been  added.  On 
fluid  media  this  diplococcus  grows  out  into 
streptococci,  and  even  in  pneumococcal  affec- 
tions streptococci  may  be  found  comprised 
of  five  or  six  elements,  the  whole  of  the 
chain  being  surroimded  by  a  capsule  similar 
to  that  described  in  the  diplococcal  form. 
The  organism  stains  rapidly  by  Gram's 
method,  and  by  the  ordinary  aniline  dyes ;  it 
does  not,  however,  grow  with  ease  upon  the 
ordinary  laboratory  media,  but  requires  some- 
what special  treatment.  It  is  exceedingly 
sensitive    to   the    degree    of   alkalinity   of   the 


medium  in  which  it  is  growing,  and  further 
requires  (especially  the  higlily  pathogenic  forms) 
some  admixture  of  serum,  ascitic  fluid,  or 
hydrocele  fluid  to  the  medium  in  which  it  is 
grown. 

A  typical  growth  of  the  organism  may  be 
obtained  on  agar  smeared  with  fresh  blood,  as 
originally  described  by  Washbourn  (42),  (43). 

The  organism  grows  but  jioorly  on  gelatin. 
It  is  to  be  found  with  singular  frequency  in  the 
saliva  of  normal  individuals ;  and  Washbourn 
and  Eyre  (16)  have  shown  that  about  five  per 
cent  of  normal  inchviduals  harbour  typical 
pathogenic  pneumococci  in  their  saliva.  Many 
other  observers  have  found  virulent  pneumo- 
cocci in  the  mouths  of  normal  persons  unaffected 
with  chsease ;  others,  again,  go  so  far  as  to  say 
that  it  is  present  in  all  mouths. 

The  pneumococcus  may  be  raised  to  an 
extraordinary  pitch  of  virulence  by  passage 
through  the  bodies  of  susceptible  animals,  the 
method  of  procedure  being  as  follows — 

An  animal  is  uifected  with  a  pure  culture  of 
pneumococcus,  and  after  a  .short  interval — one 
to  two  days — it  is  killed,  and  the  body  incubated 
for  twenty -four  hours ;  blood  is  then  taken 
from  the  heart  under  aseptic  precautions, 
and  inoculated  directly  into  another  animal. 
By  this  means  the  \'irulence  of  the  organism 
may  be  raised  considerably ;  in  fact,  Wash- 
bourn and  Eyre  were  able  to  raise  the 
virulence  of  numerous  strains  of  pneumococci 
to  such  a  pitch  that  jTnjxTTrTrcr  o^  ^  milligramme, 
corresponding  to  about  fifty  to  eighty  cocci,  was 
sufficient  to  cause  the  death  of  susceptible 
animals  (rabbits)  in  forty-eight  hours,  with  all 
the  typical  signs  of  pneumococcal  infection. 

The  pneumococcus  is  often  to  be  found  in- 
fecting the  gum  margins  in  certain  forms  of 
alveolar  infection,  often  as  a  mixed  infection 
in  cases  of  so-called  "  jjyorrhoea  alveolaris". 
The  form  found  in  the  mouth  is,  however,  rarely 
so  pathogenic  as  that  found  in  the  pneumonic 
lung  ;  Washbourn  and  Eyre,  in  the  paper  referred 
to  above,  found  that  the  organism  required 
the  passage  through  a  larger  number  of  animals 
to  raise  it  to  a  given  standard  of  \-irulence, 
than  did  the  organism  obtained  from  the  lung 
of  a  person  who  had  died  of  pneumonia ;  in 
the  latter  case  only  seven  passages  were  re- 
quired, whilst  in  the  former  some  twenty-eight 
were  necessary. 

The  pneumococcus  ferments  a  number  of 
carbo-hydrates  used  in  testing  bacteria,  but 
differs  from  the  streptococcus,  to  which  it 
is  so  closely  related,  in  the  fact  that  it  rarely 
clots  milk,  and  does  not  ferment  manitol, 
cane  sugar,  salicin,  and  inulin. 

Pneumococcal  sore  throat,  and  pneumococcal 
gastritis  are  not  uncommon ;  whUst  meningitis 


265 


and  pyaemia,  besides  classical  pneumonia,  may 
all  be  caused  by  the  pneumococcus.  It  may 
be  that  residence  in  inflammatory  lesions  of 
the  mouth  tends  to  increase  the  virulence  of 
the  pneumococcus,  for  when  testing  the  blood 
of  persons  in  whose  mouths  the  pneumococcus 
has  been  found  associated  \\  ith  an  inflammatory 
lesion,  distinct  variations  from  the  normal  in 
the  pneumo-opsonic  index  have  been  found  ;  the 
blood  of  such  persons  occasionally  jiroduces 
agglutination  of  the  pneumococcus. 

Tlie  pneumococcus,  hke  other  streptococci, 
may  produce  a  haemolytic  ferment,  but  this  is 
not  so  common  as  with  the  other  varieties  of 
streptococci. 

Streptococci. — The  first  division  of  the  strepto- 
cocci into  varieties  was  made  by  von  Lingelsheim 
(29),  who  separated  the  streptococci  into  t\xo 
main  varieties,  using  as  criteria  the  length  of 
the  chains.  His  two  divisions  were  therefore 
Streptococcus  Loiujus  and  Streptococcus  Brevis. 
The  typical  form  of  the  streptococcus  longus 
was  the  Streptococcus  Pyogenes,  occurring  in 
infective  processes  in  the  human  subject,  whilst 
the  streptococcus  brevis  was  the  organism 
typically  found  inhabiting  the  mouth. 

A  great  deal  of  work  has  been  devoted  to  the 
different  classes  of  streptococci,  and  following 
the  method  of  Gordon,  and  later  Andrews  and 
Horder  (2),  an  attempt  has  been  made  to 
separate  the  cocci  of  this  class  into  groups 
according  to  the  fermentation  of  various  carbo- 
hydrate media,  the  carbo-hydrate  media  used 
by  Gordon  consisting  of  glucose,  lactose, 
galactose,  inulin,  salicin,  coniferin,  and  manitol ; 
the  organisms  were  also  growii  on  neutral  red 
broth  anaerobicalh',  litmus  niUk,  and  gelatin. 
By  using  the  carbo-hydi'ates,  Andrews  and 
Horder  obtained  about  twenty-six  species  of 
streptococci,  and  suggested  an  arrangement 
of  the  streptococci  into  certain  groups  according 
to  the  type  of  fermentation  produced  by  them. 
The  groups  were  found  to  merge  into  one  another 
very  greatly,  but  the  fermentations  allowed 
grouping,  which,  although  not  con.sistent,  was 
exhibited  by  a  large  number  of  the  species 
tested  ;  and  it  was  thought  that  just  as  species 
in  the  animal  kingdom  show  considerable 
variation  from  the  typical  form,  so  the  strepto- 
cocci might  be  considered  to  show  de\-iations 
from  the  main  grouping.  By  the  adoption 
of  this  method  the  following  streptococcal 
groups  are  suggested  : — 

1.  Streptococcus  Pyogenes. 

2.  Streptococcus  Faecalis. 

3.  Streptococcus  Angiosus. 

4.  Streptococcus  Salivarius. 

5.  Streptococcus  Mitior. 

On  examining  a  large  scries  of  cultures,  it 
was  found  that  the  division  into  long  and  short 
9  * 


chains  did  not  coirespond  witli  the  pathogenicity 
and  non-pathogenieity  of  the  species;  for  whilst 
several  non-pathogenic  forms  of  .streptococci 
were  found  to  show  very  long  chains,  liighly 
virulent  streptococci  that  grew  only  in  very 
short  chains  were  also  discovered.  It  is,  how- 
ever, very  difficult  to  form  any  proper  con- 
ception of  the  grouping  of  streptococci  witliin 
the  limits  of  this  chapter,  and  for  the  general 
purpo.se  of  description,  therefore,  the  strepto- 
cocci of  the  mouth  may  be  considered  as — 

(1)  Non-pathogenic     streptococci     occurring 

commonly  in  the  mouth ; 

(2)  Pathogenic  streptococci  rarely  presented 

in  the  mouth. 

Non-Pathogenic. — In  practically  all  mouths  the 
organisui  called  by  Lingelsheim  Streptococcus 
Brevis,  and  iiy  Gordon  and  Holder  Strepto- 
coccus Salivarius,  may  be  found.  In  the  mouth 
the  typical  form  of  this  organism  is  diplococcal, 
and  if  a  smear  is  taken  from  the  inside  of  the 
mouth  and  stained,  a  number  of  epithelial  cells 
will  be  found  surrounded  by  diplococci.  If  a 
small  amount  of  saliva  is  placed  in  a  drop  of 
melted  agar  and  smeared  over  a  coverslip,  and 
the  coverslip  is  placed  on  a  hanging-drop  slide, 
an  epithelial  cell  may  be  found  surrounded  by 
these  cocci.  If  this  is  marked,  and  the  prepara- 
tion placed  in  the  incubator,  in  the  course  of 
twenty-four  hours  the  diplococci  grow  out  into 
streptococci.  This  particular  form  of  strepto- 
coccus was  also  originally  described  by  Miller 
as  the  Streptococcus  Xcvijer,  on  account  of  the 
chains  formed.  The  organism  stains  by  Gram's 
method,  and  by  the  usual  anihne  dyes.  In- 
jected into  animals  it  is  non-pathogenic,  and 
produces  no  localized  lesion,  and  no  general 
infection  of  the  blood  stream,  even  when  very 
large  quantities  are  used.  It  is  one  of  the 
commonest  of  all  streptococci,  and  is  difficult 
to  eliminate  from  colonies  of  other  bacteria 
on  plating  out  impure  cultures  made  from  the 
mouth.  The  organism  closely  resembles  the 
.streptococci  found  in  the  mucous  membranes 
in  other  parts  of  the  body.  In  crowded  assem- 
blies, it  has  been  found  in  the  air  by  Gordon 
and  others.  The  organism  ferments  a  number 
of  carbo-hydrates  with  ease.  It  is  frequently 
found  not  only  in  the  superficial  layers,  but  in 
the  deep  layers,  of  carious  dentine,  where,  owing 
to  its  power  of  fermenting  carbo-hydrates,  it 
may  be  regarded  as  one  of  the  chief  organisms 
concerned  in  the  actual  dissolution  of  the  lime 
salts  of  the  teeth  by  its  active  acid  fermentation. 

Pathogenic  Streptococci  of  the  Mouth. — from 
time  to  time  streptococci  having  a  defuiite 
degree  of  pathogenicity  are  to  be  isolated  from 
the  oral  secretions.  In  pathological  processes 
of  the  mouth,  tongue  and  throat,  the  strepto- 


266 


coccus  is  often  an  active  agent ;  in  various  forms 
of  recurrent  sore  throat,  the  streptococcus  may 
be  the  only  infecting  organism,  and  in  a  number 
of  cases  of  so-caUed  "  pyorrhoea  alveolaris  "  an 
almost  pure  culture  of  the  streptococcus  pyogenes 
may  be  obtained,  differing  in  many  respects 
from  the  ordinary  accepted  type  of  the  strepto- 
coccus brevis  or  salivarius. 

Culturally,  the  more  pathogenic  streptococci 
differ  from  the  sapropliHic  streptococci  in  their 
less  active  powers  of  carbo-hydrates  fermenta- 
tion ;  and  although  this  is  not  an  absolute  test, 
yet  it  is  found  as  a  matter  of  fact  that  the  less 
actively  fermenting  streptococci  are  always 
found  amongst  the  pathogenic  varieties.  On 
the  other  hand,  the  streptococcus  faecalis,  often 
found  as  an  infecting  agent,  and  occurring 
typically  in  the  alimentary  canal,  particularly 
in  its  lower  third,  may  be  sometimes  found  in 
the  mouth,  its  chief  differential  point  from  the 
other  streptococci  being  its  power  of  fermenting 
manitol. 

The  normal  mouth  streptococcus  rarely  forms 
chains  in  the  mouth  itself,  and  if  a  defuiite 
streptococcus  is  found  on  examining  smears 
from  the  pus  of  a  pathological  process  in  the 
mouth,  such  a  streptococcus  is  almost  invariably 
of  a  pathogenic  nature,  and  is  causing  some, 
if  not  all,  of  the  inflammation  present. 

A  number  of  the  pathogenic  streptococci, 
and  a  few  also  of  the  non-pathogenic,  produce 
haemolytic  ferments,  and  as  William  Hunter 
has  shown  in  pernicious  anaemia,  streptococcal 
infection  of  the  mucosa,  and  even  the  deeper 
layers  of  the  tongue,  is  not  uncommon ;  the 
haemolytic  function  of  the  streptococci  is  there- 
fore of  extreme  importance  in  all  secondary 
anaemias  associated  with  oral  infection. 

The  Streptococcus  Erysipelatus,  a  most  highly 
pathogenic  streptococcus,  is  the  chief  cause  of 
generalized  septicaemia,  and  of  pyaemia,  bone 
infections,  cerebral  infections,  and  many  forms 
of  so-called  septic  processes  affecting  various 
parts  of  the  body ;  and,  as  streptococci  often 
defuiitely  virulent  may  be  obtained  from  the 
mouth,  it  must  always  be  borne  in  mind  as 
a  source  of  infection  in  such  diverse  diseases 
as  streptococcal  peritonitis,  chronic  infective 
endocarditis,  acute  meningitis,  etc. 

A  species  of  streptococcus  closely  allied  to 
the  ordinary  streptococci,  but  coming  generic- 
ally  between  them  and  the  pneumococcus,  is 
an  organism  described  by  Burger  (10).  The 
organism  has  many  of  the  characteristics  of  , 
the  pneumococcus,  and  others  of  the  strepto- 
coccus, but  it  differs  from  the  latter  in  de- 
veloping a  capsule  in  an  ordinary  culture 
medium,  and  is  found  to  vary  in  many  other 
particulars  from  the  typical  streptococcus;  for 
further  particulars  the  student  is  referred  to 
the  original  jjapers. 


Tlie  thermal  death-point  of  the  streptococci' 
is  not  high,  58°  C.  for  half  to  three-quarters  of 
an  hour  being  sufficient  to  destroy  the  organism, 
and  this  temperature  may  be  used  in  the 
preparation  of  vaccines. 

The  great  increase  in  attention  to  the  strepto- 
cocci coincident  \nth  the  adoption  of  vaccine 
therapy  in  the  treatment  of  many  chronic 
diseases  has  Ijrought  to  light  many  facts  re- 
lating to  the  strejDtococci  that  were  hitherto 
unknowii,  but  the  production  of  vaccines  and 
the  control  of  the  dosage  are  perhaps  more 
difficult  with  this  class  of  organism  than  any 
other,  mainly  because  of  the  great  difficulty  of 
standardizing  the  vaccines.  The  streptococci 
produce  definite  toxins,  and  owing  to  this  fact 
it  is  possible  to  use  cultures  of  the  streptococci 
for  the  production  of  anti-streptococcal  serum. 
In  reported  cases  of  therapeutic  use  of  anti- 
streptococcal  serum,  great  divergence  is  found 
in  the  curative  effects  produced  by  the  injection 
of  such  serum.  This  is  not  surprising,  in  view  of 
the  great  variation  in  the  cultural  characters 
of  the  various  streptococci,  as  brought  out  by 
the  work  of  Andrews  and  Horder ;  and  it  is 
probaljle  that  in  the  cases  in  which  a  strepto- 
coccal serum  acts  with  curative  effect,  the 
organisms  used  to  produce  the  serum  happen 
to  coincide  with  the  particular  type  of  strepto- 
coccus causing  the  infection ;  it  is  for  this 
reason  that  in  producing  anti-streptococcal 
serum,  as  many  varieties  of  streptococci  as 
possible  are  made  use  of  in  immunizuig  the 
animals  (horses)  [polyvalent  vaccine]. 

For  further  details  about  the  streptococci 
the  student  is  referred  to  the  various  papers 
in  the  Cenlralhlalt  fiir  Bakteriologie,  and  also 
to  the  work  of  von  Lingelsheim,  in  KoUe  and 
Wassermann's  Hawlhuch. 

GROUP  II~BACILLI 

Among  the  organisms  found  in  the  mouth 
as  adventitious  forms,  by  far  the  largest  number 
belong  to  the  group  of  bacilli.  Certain  organ- 
isms commonly  found  in  the  throat,  and  in 
other  parts  of  the  body,  are  from  time  to  time 
found  inhabiting  tlie  mouth,  and  require  to 
be  briefly  mentioned ;  but  as  they  are  all  of 
them  fully  described  in  the  text-books  on 
general  Ijacteriologj^,  only  a  general  reference 
to  them  is  necessary.  At  the  same  time,  lesions 
of  the  mouth  are  often  attributable  to  one  or 
other  of  these  particular  bacteria. 

So  far  as  is  known,  the  organisms  occurring  in 
the  mouth  do  not  produce  spores  m  the  mouth, 
and  although  some  of  them  are  capable  of 
sporulation  outside  the  mouth,  the  presence 
of  spores  in  the  salivary  secretions  is  very 
uncommon.  Morphologically,  bacilli  are  rod- 
shaped  or  cylindrical  organisms,  in  \\hich  the 


267 


length  is  at  least  twice  the  diameter.  As  with 
the  cocci,  they  may  be  arranged  in  different 
groups  according  to  their  method  of  develop- 
ment— 

Bacilli — single    organisms    witli    the    above 

characters. 
Diplobacilli — two  organisms  attached  to  one 

another  end  to  end. 
Streptobacilli — bacilli  in   chains  of    three   or 

more  elements. 

Many  of  the  mouth  organisms  also  belong  to 
the  class  of  anaerobic  bacilli,  but  these  will  be 
described  separately ;  most  of  the  pathogenic 
forms  met  with  in  the  mouth  are  facultative 
anaerobes. 

Various  races  and  genera  of  bacilli  isolated 
from  the  oral  cavity,  although  exhibiting 
the  main  cultural  characteristics  of  the  group, 
do  not  all  conform  to  type ;  moreover,  a 
number  of  species  related  to  certain  groups 
are  to  be  found.  The  latter  statement  is 
particularly  true  of  the  diphtheria  bacillus, 
and  the  colon  bacillus ;  and  for  this  reason  it 
is  common  to  speak  of  diphtheroid  bacilli, 
meaning  organisms  resembling  in  both  morpho- 
logical and  cultural  characters  the  true  diph- 
theria bacillus,  but  differing  from  that  organism 
both  in  the  power  of  producing  toxins  and 
pathogenic  effects  in  animals,  and  also  in 
ceitain  peculiarities  in  the  general  cultural 
characteristics. 

A  considerable  amount  uf  discussion  has  raged 
around  the  group  of  organisms  that  may  be 
regarded  as  the  diphtheria  group,  and  much 
research  has  been  directed  towards  this  par- 
ticular family.  The  chief  organism  of  the  group 
is  the  diphtheria  bacillus. 

Bacillus  Diphtheriae  {Klehs-Loefjler  Bacillus). 
This  is  a  bacillus  of  5  to  6  /«,  in  length,  and 
about  '75  /x  in  width,  staining  by  Gram's  method 
and  l)y  the  ordinary  aniline  dyes.  It  grows 
best  on  the  surface  of  Loeffier's  blood  serum,  a 
medium  consisting  of  nutrient  broth  and  normal 
serum  mixed  together,  and  inspissated  at  a 
temperature  of  70°  C,  and  afterwards  sterilized 
by  the  intermittent  method  in  streaming  steam. 
On  the  surface  of  this  medium  the  organism 
rapidly  develops,  and  in  making  cultures  from 
throats  of  persons  suspected  of  clinical  diph- 
theria, this  medium  is  commonly  used.  At 
the  end  of  twenty-four  hours  typical  colonies 
of  the  di])htheria  bacillus  develop,  for  on  this 
medium  they  grow  more  quickly  than  the  other 
organisms,  streptococci  and  staphylococci,  which 
are  invariably  present.  With  Loeffler's  methy- 
lene blue,  or  with  ordinary  carbolic  methj'lene 
blue,  the  diphtheria  bacillus  stains  in  a  typical 
manner,  showing  a  series  of  darker-stained 
areas  throughout  its  length;    three  or  more  of 


these  areas  are  present  in  the  typical  organism. 
Another  constant  form  is  the  so-called  "  sheath  " 
form  or  diplobacillary  form,  the  organisms  being 
tapered  and  triangular,  and  the  two  bacilU 
approximated  to  one  another  by  their  bases; 
the  whole  organism  is  surrounded  by  a  fine 
unstained  area  when  methylene  blue  is  used. 
In  addition,  the  bacilli  may  be  found  arranged 
in  so-called  palisade  form,  in  which  several 
lie  with  their  long  axes  parallel  to  one  another 
in  groups.  The  ends  of  the  bacilli  in  many 
instances  show  slight  enlargement,  producing 
club-shaped  forms ;  the  cluljs  as  a  rule  stain 
deeply.  The  deeper  staining  granules  in  the 
I  diphtheria  bacillus  may  be  also  stained  typically 
j  by  means  of  Neisser's  stain  (acid  methylene  blue, 
I  followed  by  a  watery  solution  of  Bismarck 
brown).  By  tliis  method  the  granules  .stain 
deep  blue,  and  the  rest  of  the  organism  a  faint 
yellow.  In  coverslip  preparations  made  from 
true  diphtheritic  membrane,  this  specific  stain- 
ing is  invariably  seen,  and  is  of  great  use  for  the 
rapid  preliminary  diagnosis  in  the  determmation 
1  of  clinical  chphtheria.  The  members  of  the 
diphtheroid  groujj,  a  large  number  of  which 
closely  resemble  the  diphtheria  ))acillus,  do  not 
stain  in  this  typical  manner. 

If  pure  cultures  of  the  organism  itself,  or 
filtered  broth  cultures,  are  inoculated  into  an 
animal  (guinea-pig),  death  results  in  the  course 
of  twenty-four  to  seventy-two  hours,  with 
typical  haemorrhagic  inflammation  of  the  supra- 
renal capsules,  and  signs  of  general  toxaemia. 
If  a  sub-minimal  fatal  dose  of  toxin  is  ad- 
ministered to  a  susceptible  animal,  the  animal 
recovers ;  and  if  the  process  is  repeated  on 
several  occasions,  the  dose  being  gradually 
increased,  the  animal  finally  becomes  immune 
to  large  quantities  of  fully  virulent  and  living 
cultures.  Wien  the  animal  has  been  immun- 
ized in  this  maimer,  its  blood  serum,  obtained 
under  a.septic  precautions,  is  capable  of  pro- 
tecting a  susceptible  animal  from  many  times  a 
fatal  do.se  of  cliphtheria  toxin,  and  advantage 
is  taken  of  this  circumstance  in  the  treatment 
of  diphtheria  in  the  human  being.  Horses  are 
immunized  by  means  of  the  diphtheria  toxin 
and  bacillus,  their  blood  is  then  obtained 
aseptically,  the  serum  separated  off  under 
aseptic  precautions,  and  standardized  by  test- 
ing its  protective  power  on  susceptible  animals 
(guinea-pigs).  The  standardized  serum  is  known 
as  diphtheria  antitoxin,  and  is  used  both  during 
the  disease  itself  and  as  a  prophylactic  to 
i  prevent  its  development  in  fiersons  exposed 
to  infection  by  the  diphtheria  bacillus. 

The  Diphtheroid  Group. — A  certain  number  of 
organisms  belonging  to  this  group  are  found 
in  various  parts  of  the  tod}',  ajid  in  certain 
infective  concUtions,  but  differ  from  the  true 
diplitheria  bacillus  by  non-production  of  toxin. 


268 


Tlie  growth  of  many  of  them  on  caibo-liydrate 
media  is  more  energetic  than  the  diphtheria 
baciUus,  which  only  ferments  ghicose. 

Hoffmanns  Bacillus,  or  Pseudo- Diphtheria 
BaciUus. — This  organism,  closely  resembling 
the  diphtheria  bacillus,  is  often  found  in  the 
mouth.  It  is  not  pathogenic  for  man  or  the 
ordinary  laboratory  animals,  and  differs  from 
the  true  diphtheria  bacillus  in  producing  the 
fermentation  of  several  carbo-hydrates.  The 
Hoffmaim  bacillus  does  not  give  the  usual  stain- 
ing reaction  with  NeisserV  stain,  and  is  nmch 
shorter  and  tends  rather  to  polar  staining ;  but 
it  exliibits  the  same  banded  staining  \\ith  methy- 
lene blue  as  the  diphtheria  bacillus — in  fact, 


*<*^%%l 


'vr>i''">,-o;  ' 


Fig.  382. — Bacillus  Hoffmann,  U  hrs.  serum  agar, 
Gram,     x  1000. 


on  agar  the  tw  o  organisms  closely  resemble  one 
another. 

HolTmami's  bacillus  is  constantly  found  in 
conditions  of  sore  throat  resembling  the  diph- 
theritic throat,  but  without  membrane ;  it 
may  often  be  found  existing  in  the  throats  of 
individuals  a  long  time  after  an  attack  of  diph- 
theria, and  for  this  reason  some  observers  are 
of  opinion  that  it  is  merely  a  non-virulent 
degenerated  form  of  the  true  diphtheiia  bacillus  ; 
most  observers,  however,  consider  the  organism 
to  be  a  distinct  species. 

Xerosis  Bacillus. — This  organism  was  de- 
scribed by  Uhthoff  (39)  as  commonly  found 
in  trachoma  and  forms  of  conjunctivitis.  It 
closely  resembles  the  diphtheria  bacillus,  but 
is  non-virulent ;  it  shows  clubbing,  and  partial 
staining  in  a  high  degree ;  it  does  not  react 
to  Neisser's  stain.  It  may  be  found  in  the 
mouth  from  time  to  time  in  cases  of  chronic 


eye  disease,  gaining  entrance,  no  doubt,  by 
passing  down  the  nasal  duct  into  the  nose,  and 
thence  into  the  mouth. 

A  large  number  of  other  varieties  of  diph- 
theroid bacilli  exist.  They  are  often  found  in 
suppuration.  Thus  Dudgeon  (14)  describes  a 
diphtheroid-like  bacillus  causing  cellulitis.  C4ra- 
ham-Smith  (Jour.  Hygiene,  1904)  describes  an 
organi.sm  bacillus  auris  resembling  bacillus  diph- 
theriae  as  occurring  frequently  in  chronic  sup- 
puration of  the  ear ;  a  large  number  of  these  ear 
cases  are  found  to  be  associated  with  a  bacillus 
conforming  to  a  particular  tj^ie.  Caiitley  (11) 
describes  a  bacillus,  bacillus  coryza  .segmentosa, 
or  bacillus  septus,  occurring  in  common  colds. 
The  writer  has  frequently  found  it  also  in  suppur- 
ation of  thealveolar  margin,  often  associated  with 
the  micrococcus  catarrhalis.  Inoculations  with 
this  organism  frequently  cause  symptoms  of 
acute  coryza.  The  organism  produces  no  fermen- 
tation with  carbo-hydrate,  according  to  Cautley  ; 
j  on  the  other  hand  Bentham  states  that  an 
'  organism  of  a  similar  type  ferments  glucose 
only,  and  that  other  similar  ones  produce  an  acid 
fermentation  in  glucose,  lactose,  cane-sugar, 
and  manitol.  Bacilli  of  this  type  are  by  no 
means  inicommon  in  the  mouth,  and  may  be 
found  causing  a  species  of  pseudo-membrane 
on  the  anterior  surfaces  of  the  alveolus  in  some 
forms  of  chronic  septic  mouth.  They  stain 
by  Gram's  method,  and  grow  readily  on  the 
ordinary  media  providing  they  have  an  alka- 
linity of  -|-  3.  For  further  particulars  of  the 
cultural  characters  of  these  oi'ganisms  the 
reader  is  referred  to  papers  in  The  Lancet,  by 
Bentham,  who  gives  references. 

De  Simoni  (12)  describes  a  diphtheria-like 
bacillus  in  the  nose,  whilst  Ritter  (35)  describes 
diphtheria-like  bacilli  occurring  in  the  mouths 
of  a  number  of  children  examined.  Diphtheroid 
bacilli  are  also  to  be  found  in  the  intestinal  and 
genitourinary  canals. 

Bacillus  Tuberculosis. — The  bacillus  tuber- 
culosis is  one  of  the  well-known  pathogenic 
organisms ;  it  is  found  causing  lesions  in  the 
buccal  cavity,  .such  as  tubercular  ulcers  of  the 
palate,  tongue,  and  fauces  and  very  occasionally 
tubercular  osteitis  of  the  bone  of  the  jaws. 
Primary  tubercular  disease  of  the  jaw  is  very 
rare  ;  most  of  the  cases  of  tubercular  osteitis 
and  ulceration  of  the  soft  parts  of  the  mouth 
occur  in  persons  suffering  from  tubercular 
lesions  in  other  jjarts  of  the  body.  Tubercle 
bacilli  may  be  found  in  the  mouths  of  persons 
suffering  from  pulmonary  tuberculosis,  and 
they  have  been  demonstrated  in  the  mouths 
of  nurses  employed  in  a  phthisis  hospital  but 
unaffected  by  the  disease. 

The  tubercle  bacillus  belongs  to  the  group 
of  organisms  known  as  acid-fast,  owing  to  the 
fact  of  its  retaining  a  dye,  carbol-fuchsin,  after 


269 


treatment  with  a  mineral  acid,  siicli  as  dilute 
sulphuric  acid,  25  per  cent.  In  its  usual  form 
the  organism  is  a  tine  rod,  slightly  curved,  and 
exhibiting  irregularity  of  staining,  which  gives 
it  a  slightly  beaded  appearance.  Like  its  some- 
what near  relative,  the  diphtheria  liacillus,  it 
exhibits  branched  forms,  and  owing  to  this 
tendency  to  branching  exliibited  by  l)oth  these 
organisms  Lehmami  and  Xeumami  have  classed 
them  under  a  new  group  of  corny-hacteriiim. 

'I'he  organism  docs  not  stain  with  the  ordinary 
aniline  dyes  used,  but  may  be  stained  by 
Gram's  method,  although  l»ut  feebly.  It  does 
not  grow  on  the  usual  culture  media,  hut  re- 
quires the  addition  of  10  %  glycerine.  The 
method  of  obtaining  pure  cultures  is  somewhat 
laborious.  It  is  best  performed  by  plating 
sputum  having  a  high  tubercular  content,  and 
after  twenty-four  hours  removing  portions  of 
the  agar  that  are  free  from  colonies  of  the 
ordinary  rapidly  growing  bacteria ;  the  small 
portions  are  placed  in  other  tubes,  and  the 
organism  slowly  develops.  Its  growth  much 
resembles  that  of  streptothrix,  being  hard, 
wrinkled,  and  lichen-like  in  appearance.  It 
grows  easily  on  the  surface  of  glycerine  broth, 
and  this  medium  is  made  use  of  for  the  prepara- 
tion of  tuberculin. 

For  the  treatment  of  chronic  tubercular 
lesions  tuberculin  is  often  made  use  of,  or  else  a 
bacillary  emulsion,  the  solution  being  in  the  one 
case  the  filtered  toxin  of  the  organisms  (T.  R.), 
and  in  the  other  a  triturated  culture  containing 
the  bodies  of  the  organisms  themselves  (B.  E.). 

The  tubercle  bacillus  is  pathogenic  for  the 
lower  animals,  as  well  as  for  man,  and  for  the 
purposes  of  diagnosis,  when  the  organism  cannot 
be  found  microscopically  by  the  Ziehl  Neelson 
method  of  staining,  an  animal  (guinea-pig)  is 
inoculated.  In  a  large  number  of  cases  in 
which  no  l)acilli  can  be  demonstrated  by  staining 
methods,  the  injected  animal  exhibits  well- 
marked  tubercular  lymphangitis ;  and  it  is 
supposed  by  some  observers  that  in  such  cases 
a  |)ecuharly  small  form  of  the  bacillus  exists, 
which  does  not  stain  by  the  usual  methods 
adopted.  Tlie  peculiar  acid-fast  staining  of  the 
tubercle  bacillus  is  due  to  a  wax-like  body  that 
it  contains. 

BaciUwi  Lepra. — The  bacillus  of  leprosy 
closely  resembles  the  tubercle  bacillus  in  its 
staining  characters,  in  that  it  is  acid-fast,  but 
it  more  ra])idly  undergoes  decolorization  with 
dilute  mineral  acids  than  the  tubercle  bacillus. 
It  is  found  in  vast  numbers  in  the  lesions  of 
leprosy,  and  generally  arranged  in  characteristic 
masses.  Leprous  lesions  are  not  common  in 
the  mouth,  but  in  cases  of  advanced  leprosy, 
where  the  tonsils  are  aifected,  and  also  in  ca.ses 
of  nasal  leprosy,  it  is  common  to  find  the  bacillus 
in  the  mouth. 


According  to  Bayon  (7)  (8)  the  leprosy  bacillus 
may  be  gro\\'n  in  pure  culture.  The  organism 
undergoes  a  curious  variation,  which  no  doubt 
accounts  for  the  failure  of  many  persons  to 
obtain  cultures  of  the  organism.  Some  of  the 
cultures  that  Bayon  obtained  exhibited  varia- 
tion in  the  acid-fast  staining ;  this  was  absent 
in  the  early  cultures  but  gradually  developed  as 
the  organism  became  accustomed  to  the  artificial 
media. 

Inoculation  of  the  pure  cultures  into  animals 
produces  characteristic  lesions  with  the  char- 
acteristic grouping  of  the  leprosy  bacilli. 

Bacillus  Pyocijaneus. — This  is  a  fine  rod- 
shaped  organism  with  square  or  round  ends, 
3  to  4  yx  in  length,  or  less,  about  0'3  /j,  wide,  and 
possessed  of  peritricheal  flagella.  It  does  not 
form  spores,  is  decolorized  by  Grams  method, 
and  stains  by  the  ordinary  aniline  dyes.  Two 
pigments  are  produced,  as  well  as  a  toxin. 

Several  non-pathogenic  organisms  are  closely 
allied  to  the  bacillus  pyocyaneus  ;  these  produce 
one  or  other,  but  never  both,  of  the  pigments 
produced  by  the  bacillus  pyocyaneus.  The  pig- 
ments are  the  green  tluorescin,  and  the  orange 
or  brown  pigment,  pyocyanin;  the  latter  \Ag- 
ment  is  not  formed  unless  a  considerable 
amount  of  proteid  is  present. 

The  organism  occurs  sometimes  in  suppura- 
tive lesions,  such  as  dento-alveolar  abscesses, 
but  is  not  very  common.  Wien  it  is  present 
in  the  mouth,  it  may  also  be  found  in  the  faeces ; 
it  may  be  an  infecting  organism  in  ear  disease, 
and  may  then  gain  entrance  to  the  throat. 
Filtered  cultures  of  the  organism  injected  into 
animals  j^roduce  symptoms  similar  to  those 
caused  by  inoculation  of  the  living  bacillus. 

A  considerable  amount  of  early  bacteriological 
work  on  toxins  and  immunity  was  performed 
with  the  bacillus  pyocyaneus.  Its  recognition 
gives  little  difficulty  ;  the  bright  green  fluorescent 
pigment,  its  non-Gram  staining,  its  motility, 
etc.,  are  all  points  that  render  it  easy  of 
determination. 

Bacillus  Coli  Communis. — The  bacillus  coli 
communis  is  an  organism  constantly  found  in 
the  faeces  and  in  the  large  intestine,  hut  only 
occasionally  in  the  mouth;  and  although  a 
curious  foetid  smell  may  be  met  with  in  fluid 
media  cultures  made  from  the  mouth,  the 
odour  is  only  very  rarely  due  to  tiie  bacillus  coli 
commune. 

A  number  of  organisms  are  closely  related  to 
the  colon  group,  dilYering  from  the  colon  bacillus 
it.self  in  their  special  fermentation  of  carbo- 
hydrates, and  the  carbo-hydrate  tests  are  used 
with,  perhaps,  greater  atlvantage  in  the  differen- 
tiation of  tiie  colon  group  than  any  other  series 
of  organisms. 

The  organism  itself  is  an  exceedingly  short 
bacillus,  often  arranged    as  diplobacilli,  about 


270 


rS  /x  in  length,  and  "5  /i  in  width.  It  does 
not  stain  by  Gram's  mctliod,  ahhough  by 
careful  decolorization  a  certain  number  of  the 
individual  bacilli  are  found  partly  to  retain 
the  stain.  The  organism  is  highly  motile, 
possessing  peritricheal  flagella.  It  produces 
gas  and  acid  when  grown  on  glucose,  lactose, 
malto.se,  inulin,  manitol,  etc.,  but  according 
to  MacConkey  (30)  rarely  produces  fermenta- 
tion of  cane-sugar.  The  organism  is  frequently 
found  in  mUk  and  water,  and  its  presence  shows 
faecal  contamination.  It  is  pathogenic  for 
animals,  when  injected  in  large  doses,  and  may 
be  raised  to  a  considerable  pitch  of  virulence 
by  tlie  method  of  passage. 

For  a  full  description  of  this  organism  see  the 
text-books  on  Bacteriology. 

Bacillus  Friedlii  ruler. — The  bacillus  Fried- 
lander  is  closely  allied  to  the  colon  group  in  its 
carbo-hydrate  fermentation,  but  differs  from 
the  bacillus  coli  in  many  respects,  and  is,  as  a 
rule,  a  much  longer  organism.  It  was  first 
described  by  FriedJiinder  as  the  cause  of  pneu- 
monia. It  is  present  in  many  cases  of  lung 
infection,  often  associated  with  the  pneumo- 
coccus,  and  wlien  found  in  the  sputum  is.  as  a 
rule,  surrounded  by  a  gelatinous  capsule  staining 
by  the  ordinary  methods  of  capsule  demonstra- 
tion. When  grown  in  gelatine  stabs,  large 
buljbles  of  gas  form  along  the  length  of  the 
stab ;  it  does  not  hquefy  the  gelatine.  It  is 
Gram-negative,  and  jiroduces  localized  tissue 
necrosis  wlien  inoculated  into  animals.  It  is  by 
no  means  an  uncommon  organism  in  the  mouth, 
and  may  be  often  found  as  the  cause  of  localized 
suppuration,  ulceration,  or  post-nasal  catarrli. 

The  bacillus  rhinosclcroma  and  tlie  bacillus 
ozoenae  are  generally  considered  to  be  variants  of 
the  Friedlander  bacillus,  and  are  found  associ- 
ated with  the  pathological  conditions  from 
which  they  derive  their  names.  They  all 
rapidly  ferment  a  number  of  carbo-hydrates, 
w  ith  the  production  of  acid  and  gas.  The  chief 
difference  between  these  organisms  lies  in  the 
question  of  carbo-hydrate  fermentation,  and  for 
particulars  in  this  direction  the  student  is 
referred  to  the  literature  on  the  subject. 

The  other  closely  allied  organisms  occasion- 
ally found  in  the  mouth  are  bacillus  cloacae  of 
Jordan  and  bacillus  ox^i^ocus  perniciosus  ;  their 
differentiation  depends  upon  their  carljo-hydrate 
reactions. 

Bacillus  Influenza. — The  bacillus  influenza 
may  be  regarded  as  one  of  the  mouth  bacteria. 
It  is  found  in  the  sputum  and  saliva  of  persons 
suffering  from  typical  influenza,  as  well  as  in 
the  mouths  of  perfectly  healthy  persons. 

The  organism  is  exceedingly  small,  being  only 
about  1  /x  in  length,  and  about  '25  fi  or  less  in 
breadth;  it  occurs  as  diplobacilli,  and  is 
typically  found  lying  amongst  and  in  the  cells 


of  the  sputum.  The  organism  is  exceedingly 
delicate  in  its  growth,  and  will  only  grow  on 
blood-agar  or  normal  blood-serum-agar  (one 
part  of  normal  unlieated  serum  to  two  parts  of 
agar,  mixed  at  40°  C).  On  the  surface  of  thia 
medium  the  organism  forms  round  colourless 
transparent  globules,  often  compared  to  drops 
of  dew,  which  rarely  become  confluent  into  a 
definite  streak.  The  organism  is  Gram-negative, 
and  stains  best  with  carbol-fuchsin.  The  usual 
method  of  demonstrating  its  presence  in  sus- 
pected material  is  by  means  of  prolonged  stain- 
ing with  very  dilute  carljol-fuehsin,  the  speci- 
mens being  left  from  one  to  four  hours  in  the  hot 
incubator. 

The  organism  is  not  very  pathogenic  for 
animals,  but  has  been  definitely  determined  as 
the  exciting  cause  of  tnie  influenza.  The 
organism  is  occasionally  found  in  the  blood  of 
persons  suffering  from  clinical  influenza. 

The  organism  is  rapidly  killed  by  a  short 
exposure  to  60°  C,  and  ceases  to  grow  below 
22°  C. 

The  influenza  bacillus  undoubtedly  produces 
a  toxin  of  extreme  virulence,  and  a  large  number 
of  cases  of  post-influenzal  nervous  affection  are 
known — in  tact,  nerve  diseases  are  particularly 
prone  to  occur  as  sequelae  of  genuine  influenza. 

Bacillus  Necrodentalis.- — This  organism  is  con- 
stantly found  in  the  mouth,  and  is  particularly 
associated  with  dental  caries.  The  organism 
is  a  small  oval  bacillus,  2  to  2' 5  /t  long  and 
0'75  /JL  wide,  occasionally  occurring  in  pairs, 
with  almost  a  coccal  appearance — more  par- 
ticularly in  aerobic  cultures.  The  organism  is 
facultative  anaerobic,  and  often  oiJy  develops 
in  preliminary  cultures  under  anaerobic  or  semi- 
anaerobic  conditions.  It  is  to  be  found  along 
the  gum  margins,  and  typically  in  the  deeper 
layers  of  carious  dentine,  and  associated  \\ith 
the  streptococcus  salivarius  of  the  mouth.  On 
agar  the  growth  closely  resembles  that  of  the 
streptococcus,  but  no  turbidity  occurs  in  broth, 
and  very  little  deposit,  what  is  formed  being  of 
a  stringy  consistency  and  remaining  attached 
to  the  bottom  of  the  tube  on  shaking.  An- 
aerobically  the  organism  tends  to  grow  out  into 
longer  bacillary  forms  than  under  aerobic 
environment,  and  well  marked  irregular  bacilli 
may  be  observed  in  .such  cultures.  The  organism 
is  not  motile,  produces  no  spores,  and  stains  by 
Gram's  method  and  ordinary  aniline  dyes. 

It  is  slightly  pathogenic  for  animals,  pro- 
ducing locahzed  tissue  necrosis,  and  occa.sionally 
generalized  infection  when  inoculated  into 
rabbits.  In  guinea-pigs,  an  occasional  local 
abscess  is  formed,  but  only  when  a  considerable 
quantity  of  the  organism  is  injected. 

The  organism  rapidly  ferments  glucose,  lac- 
tose, and  suchrose,  but  not  inulin  and  manitol ; 
acid  only,  and  no  gas,  is  formed. 


271 


It  is  often  found  in  the  nose  ;  and  Lewis  (28), 
in  the  examination  of  a  number  of  cases  of  disease 
of  the  maxillary  sinus  due  to  various  tyjies  of  in- 
fection, found  this  organism  in  many  of  the  cases. 

Tlie  organism  does  not  liquefy  gehitine,  but 
produces  coagulation  of  litmus-milk.  Colonies 
on  the  surface  of  agar  closely  resemble  those  of 
the  streptococcus,  but  have  an  eroded  and  irre- 
gular outline,  and  occasionally  a  small  central 
point ;  the  characters  of  the  colonies  are  extremely 
inconstant.  From  the  frequency  with  wliich 
it  is  found  in  tlie  deep  layers  of  carious  dentine, 
and  the  fact  of  its  being  an  anaerobic,  or  faculta- 
tive anaerobic  organism,  and  the  ease  with  which 
it   ferments  many  earbo-hvdrates,  it   is  highly 


>^Jkr 


I 


*  , 

it,^ 

%fl^ 

■J^ 

^"6v, 

^     *' 

^V'vo, 

*^        ,•;># 

A 

»  -''v 

•-•vv 

Fig.  383. — Streptobacillus  malae,  48  hrs.  egg  agar. 
Gram,     x  1000. 

probable   that   this   organism   is   one   of   those 
concerned  in  the  production  of  dental  caries. 

Slreplohacillus  Malae. — This  streptobacillus 
closely  resembles  in  its  morphological  characters 
the  streptobacillus  ulcus  moUe  of  Ducrey,  but 
differs  from  it  in  the  fact  that  it  will  grow  on 
ordinary  agar  ha\'ing  an  alkalinity  of  -f  3, 
Ducrey  s  organism  requiring  blood-agar. 

Cultivations  on  the  ordinary  media,  -r  10,  do  ' 
not  give  typical  cultures,  as  the  bacillus  is 
extremely  sen.sitive  to  small  degrees  of  alkalinity. 
Tlie  appearance  of  the  colonies  on  the  surface 
of  agar  is  somewhat  characteristic  ;  they  are 
irregularly  eroded,  with  a  finely  granular  appear- 
ance, but  frequently  exhibit  microscopically 
an  irregular  central  area,  darker  in  colour  and 
with  an  irregular  crystalline  appearance.  After 
several  days  on  the  surface  of  agar  they  may 
be  as  wide  as  three  to  four  millimetres,  having  an 
ill-defined  irregular  outline,  composed  of  a  darker 
bluish  ring,  with  a  central  greyish  granular  area. 


The  colonies  are  somewhat  tenacious  and 
granular,  and  when  removed  from  the  .surface, 
show  a  tendency  to  run  into  small  flakes.  It 
typically  ferments  glucose,  lactose,  cane-sugar, 
glucose,  and  lae\iilo8e,  with  the  production  of 
acid,  but  does  not  ferment  manitol,  inulin, 
salicin,  and  caffein.  Litmus-milk  is  rendered 
acid,  but  coagulation  does  not  always  occur. 

Tlie  morphology  of  the  organism  is  irregular; 
its  tj7)ical  form  consists  of  short  bacilli  joined 
together  in  long  chains,  often  of  twenty  or 
thirty  elements ;  and  interspersed  in  the  ele- 
ments are  long  shuttle-shaped  forms  taking  the 
stain  deeply.  Polar-staining  types  are  also  fre- 
quently met  with,  as  \\ell  as  large  swollen  and 
irregular  masses,  Mhich  may  be  seen  at  the  ends 
of  threads.  The  organism  stains  by  Gram's 
method,  and  by  the  usual  aniline  dyes.  It  is 
commonly  found  in  the  infective  processes  of 
the  jaw,  particularly  those  in  ^\■hich  a  large 
amount  of  destruction  of  bone  lias  taken  place 
around  affected  teeth  (rarefying  osteitis).  The 
wTiter  has  also  isolated  the  organism  on  several 
occasions  from  the  urine  of  infected  cases ;  it 
resembled  in  some  respects  the  streptobacUlus 
isolated  by  Pfeiffer  from  the  urine. 

Pure  cultivations  of  the  streptobacillus,  when 
inoculated  into  the  knee-joints  of  rabbits,  or 
into  the  periarticular  tissues,  produce  secondary 
changes  in  the  joint  and  articular  structures; 
no  suppuration  results,  but  a  low  type  of  inflam- 
mation with  hypertrophy  of  the  synovial 
membranes,  great  thickening  of  the  joint  cap- 
sule, and  rarefaction  of  the  articular  ends  of  the 
bones.  Wlien  the  injections  are  made  intra- 
venously, as  well  as  into  the  articular  tissues, 
the  changes  are  more  rapid,  and  secondary  joint 
affections  have  resulted  in  many  of  the  animals 
inoculated  by  the  ^^■riter,  including  definite 
periosteal  nodes  on  the  ribs,  and  the  organisms 
have  been  recovered  in  pure  culture  from  the 
heart,  blood,  and  periarticular  structures  as 
long  as  six  months  after  inoculation.  In  several 
animals  the  joint  swelling  and  thickening  has 
disappeared  after  two  or  three  months,  but  in 
others  progressive  changes  have  taken  place 
exactly  similar  to  those  produced  in  infective 
arthritis,  and  arthritis  deformans  of  slow  onset. 
Furthermore,  the  use  of  vaccines  prepared  from 
the  streptobacillus.  in  cases  of  arthritis  deformans 
of  oral  origin, have  beenattended  with  a  consider- 
able degree  of  success  in  the  writer's  liands ;  the 
preliminary  inoculations  have  been  often  associ- 
ated with  exacerbation  of  the  local  joint  affec- 
tion. There  is,  therefore,  a  good  deal  of  evidence 
that  this  streptobacillus  is  one  of  the  organisms 
causing  arthritis  deformans  of  oral  origin. 

Non-Pathogenic  Bacilli  ok  the  Modth 
The    writer   has   already   stated   that    many 
varieties  of  bacilli  may  be  found  in  tlie  mouth 


272 


as  adventitious  species,  and  it  is  quite  impossible 
to  tabulate  all  the  organisms  that  have  been 
described  by  various  observers  as  occurring  in 
the  mouth.  A  certain  number  of  organisms  of 
the  non-pathogenic  group  are  to  be  found  re- 
siding ill  the  mouth  and  oral  secretions  for  long 
periods,  and  may  be  found  in  the  same  mouth 
time  after  time  if  sought  for.  Such  may  appear 
in  films  made  from  pus  or  buccal  secretions,  or 
in  cultures  made  from  diseased  tissues  in  the 
mouth.  A  few  of  the  more  commonly  occurring 
forms  will  be  re\aewed.  For  this  purpose  the 
organisms  may  be  considered  as  belonging  to 
several  main  groups — ■ 

1.  Mesentericus  Group. 

2.  Proteus  Group. 

3.  Acidi  Lactici  Group. 

4.  Chromogenic  Bacilli. 

1.  The  Bacillus  Mesentericus  Group. — Tliis 
group  has  three  well  marked  varieties — 

Bacillus  Mesentericus  Vulgatus, 
Bacillus  Mesentericus  Ruber, 
Bacillus  Mesentericus  Fuscus, 

and  to  this  group  in  all  probability  belongs  the 
organism  described  by  Arkovy  (3)  as  the  bacillus 
gangrenae  pulpae,  an  account  of  which  is  given  in 
Lehmami  and  Neumaiui's  handbook. 

The  bacillus  mesentericus  group,  also  called 
potato  bacilli,  are  very  \\idely  distributed  in 
nature.  The  organisms  are  rod-shaped  bacilli, 
3  to  5  /i  in  length,  and  '5  /t  or  less  in  breadth, 
and  retain  the  stain  of  Gram's  method.  They 
are  liighly  motile,  and  all  of  them  form  spores, 
which  resist  considerable  concentration  of  dis- 
infectants, and  are  even  resistant  to  boiling 
for  as  much  as  half  an  hour.  They  produce 
proteolj'tic  enzymes,  and  digest  a  number  of 
proteids  with  considerable  rapidity.  They  do 
not  clot  milk,  but  gradually  peptonize  it. 

The  particular  characteristic  of  the  group  is 
the  curious  WTinkled  appearance  of  the  growth 
on  various  mecUa,  especially  on  the  surface  of 
boiled  potato.  Two  meml^ers  of  the  group,  the 
bacillus  ruber  and  bacillus  fuscus,  both  stain  the 
substratum  of  the  potato  deeply,  the  first  a 
reddish -brown  colour,  and  the  latter  a  blackish- 
brown.  When  present  in  association  with 
other  mouth  bacteria  they  rapidly  grow  them 
down,  and  cover  the  whole  surface  of  the 
medium.  They  are  more  common  in  carious 
dentine  than  in  the  oral  secretions,  and  may 
be  very  frequently  obtained  from  superficial 
cavities  in  molar  teeth  that  have  been  under- 
going rapid  caries.  Even  considerable  quantities 
of  the  cultures,  when  inoculated  into  animals, 
produce  no  lesion. 

The  position  of  the  spores  in  the  organism  is 
variable,  but  as  a  nde  they  are  centrally  placed  ; 


the  spores  may  be  stained  by  the  usual  spore- 
staining  methods. 

The  Subtilis  Group  is  oiJy  rarely  found  in  the 
mouth,  and  probably  only  as  an  adventitious 
species.  In  its  gro\^'th  it  resembles  somewhat 
the  bacillus  mesentericus  ruber  on  potato,  and 
grows  rapidly.  The  size  of  the  organism  makes 
it  easy  to  chfferentiate  from  the  bacillus  mesen- 
tericus. By  itself  it  cannot  be  regarded  as  a 
mouth  organism,  but  a  large  bacillus,  in  some 
ways  resembling  the  subtilis  bacUlus  in  its  size 
and  sporulation,  though  entirely  different  from 
it  in  growth,  is  the  bacillus  rnaximus  buccalis, 
which,  so  far  as  the  «Titer  is  aware,  is  only 
found  in  the  mouth. 

Bacillus  rnaximus  buccalis  is  a  large  bacillus, 
1  n-  in  width  and  5  to  6  /u.  in  length,  forming 
definite  chains.  Spores  are  produced,  wliich 
%\ithstand  a  temperature  of  80°  C.  for  over  an 
hour ;  sporulation  does  not  take  place  in  the 
mouth. 

Tlie  organism  ferments  certain  carbo-hydrates, 
coagulates  milk,  liquefies  gelatine,  and  is  not 
pathogenic  for  animals.  It  is  by  far  the  largest 
of  all  the  organisms  met  \\ith  in  the  mouth,  and 
is  the  organism  originally  described  morpho- 
logically by  Miller  as  bacillus  rnaximus  buccalis. 
It  is  non-motile,  and  Gram-positive. 

Bacillus  Plexijormis  (Goadby). — These  are 
curved  and  twisted  baciUi,  which  may  be 
associated  with  or  grow  out  into  pairs  30  yu. 
or  more  in  length.  On  gelatine,  at  the  tem- 
perature of  the  room,  a  small  white  punctiform 
colony  apjDears,  producing  gradual  liquefaction. 

On  agar,  the  organism  tends  to  grow  out  into 
very  long  irregular  threads.  These  threads  are 
frequently  swollen  in  the  centre,  and  form  long 
terminal  fine  filaments,  curved  and  twisted. 
Their  growth  on  agar  is  thick,  and  tends  to  be 
sUghtly  fluorescent,  no  definite  pigment,  how- 
ever, being  produced.  The  organism  is  Gram- 
negative. 

2.  Proteus  Group. — The  term  bacillus  proteus 
comprises  a  very  large  number  of  bacteria  of 
various  types.  Among  them  are  several  defi- 
nitely pathogenic  forms,  and  the  group  may, 
therefore,  be  regarded  as  coming  midway  be- 
tween the  pathogenic  and  non-pathogenic  bacilli 
of  the  mouth  ;  the  majority  of  the  proteus  group 
are  not  pathogenic. 

Tliree  forms  were  originally  described  by 
Hauser  (26)  and  the  strains  were  termed — 

Proteus  Mirabilis. 
Proteus  Vulgaris. 
Proteus  Zenkeri. 

The  special  feature  of  these  organisms  is  the 
curious  "  wandering  colonies  ",  which  are  formed 
on  the  surface  of  nutrient  media  in  Petri 
dishes  ;   the  colonies  are  termed  amoeboid. 


273 


.  Certain  workers,  as  Jordan,  included  under 
the  proteus  group  all  organisms  that  ferment 
sucrose  and  dextrose,  and  rarely  lactose,  and 
that  are  also  vigorously  proteolytic,  rapidly 
liquefying  gelatine  and  blood  serum,  and 
precipitating  and  then  dissolving  casein. 
Practically  all  authors  agree  in  laying  special 
stress  on  the  proteolytic  and  fermentative 
properties  of  the  group. 

None  of  the  organisms  of  this  group  are  more 
than  1  jx  in  diameter,  and  they  do  not  form 
spores;  they  are  all  motile.  They  are  non- 
chromogenic,  and  most  of  them  produce  an 
unpleasant  foetid  odour.  They  are  all  facultative 
anaerobes,  grow  at  the  body  temperature,  and 
are  al)le  to  withstand  a  very  considerable 
variation  in  the  alkalinity  or  acidity  of  the  media 
in  which  they  are  grown.  They  jji'oduce  a 
generalized  turbidity  and  precipitate  in  nutrient 
broth. 

Jlemljers  of  tliis  group  may  be  commonly 
isolated  from  carious  dentine,  more  especially 
the  superficial  layers,  and  are  to  be  regarded  as 
active  agents  in  the  destruction  of  decalcified 
tooth  tissue. 

3.  The  Bacillus  AcidiLactici  Group.  This  group 
is  closely  related  to  the  bacillus  coli  group,  and 
to  the  bacillus  lactose  aerogenes,  the  bacillus 
pneumoiuae  of  Friedlander,  and  the  bacillus 
cloacae  of  Jordan.  MacConkey,  \\ho  has  made 
a  very  complete  study  of  these  groups  of  organ- 
isms, is  of  opinion  that  both  the  acidi  lactici 
and  a  somewhat  similar  organism,  the  liacillus 
lactis  aerogenes  of  Hiippe,  may  be  differentiated 
from  the  bacillus  coli  communis,  and  are  not, 
as  is  sometimes  suggested,  non-motile  forms  of 
that  organism.  Both  the  bacillus  lactis  aerogenes 
and  the  bacillus  cloacae  give  the  Voges  and 
Proskauer  "  kalilaugerothreaktion  ". 

\The  V oges-P roskauer  Reaction. — The  method 
of  performing  this  test  is  to  add  caustic  potash 
to  the  broth  tube,  and  allow  it  to  stand  for 
twenty-four  hours  or  longer  ;  a  fluorescent  colour 
somewhat  similar  to  a  dilute  alcoholic  solution 
of  eosin  is  produced.] 

The  growth  of  bacillus  acidi  lactici  differs 
from  that  of  bacillus  coli  in  its  viscid  character 
on  agar;  the  organism  is  non-motile,  but  Gram- 
negative,  producing  a  much  denser  growth  on 
gelatine  than  bacillus  coli.  Tliese  organisms 
are  often  present  in  milk,  and  are  non-sporulat- 
ing,  they  often  gain  access  to  the  mouth,  \\here 
they  persist,  and  may  be  obtained  in  pure  culture. 

For  further  information  on  this  interesting 
group  see  MacConkey's  paper  in  The  Journal  of 
Hygiene,  1905,  giving  the  cultural  reactions  in 
fermentations,  etc.,  of  a  mimberof  allied  species. 

4.  Chromogenic  Bacilli  (Iroup.  The  other 
chromogenic  bacilli  of  the  mouth,  in  addition  to 
the  bacillus  pyocyaneus  already  cited,  are  not 
very  numerous  ;  amongst  them  the  commonest 


is  the  organism  df  scribed  by  Dobrzynicki  (13),  a 
bacillus  (bacillus  lutcns)  1-5 /x  long^  irregular  in 
size,  non-motile,  and  staining  l)y  Grams  method. 
The  organism  pioduces  a  \\ell-niarked  sulphur- 
yellow  colouiation  when  grown  at  room 
temperature.  This  organism  is  occasionally 
found  causing  the  yellow  stain  in  some  varieties 
of  salivary  calculus  ;  it  does  not  liquefy  gelatine, 
and  is  not  pathogenic  when  inoculated  into 
animals. 

Bacillus  Roseus,  or  Micrococcus  Roseus,  is  a 
very  short  plump  l)acillus,  or  oval  coccus,  and 
is  a  widel}'  distrii)uted  organism  found  in  air 
and  water  as  well  as  in  the  mouth.  It  stains 
by  the  ordinary  aniline  dyes  and  by  Gram's 
method,  and  produces  a  very  slow  liquefaction 
of  gelatine.  The  colonies  are  rather  ty])ical, 
being  raised,  cone-.shaped,  and  of  a  beautiful 
rose-red  colour,  particularly  when  grown  on 
potato.  The  rose-red  colour  is  only  produced 
aerobically,  and  at  a  temperature  of  20°  C.  Tlie 
organism  is  not  pathogenic.  It  differs  from  the 
bacillus  prodigiosus,  «hich  the  wTiter  has  never 
met  with  in  the  human  mouth. 

In  addition  to  these  two  chromogenic  bacilli, 
several  of  the  organisms  already  described 
l^roduce  pigments,  namely  : — 

Staphylococcus  A  ureus, 
Staphylococcus  Citreus, 
Sarcina  A  urantiaca, 
Sarcina  Liitea, 
Sarcina  Rosa  ; 

and  to  these  may  be  added  the  common  pink 
torula  of  the  air,  and  a  pink  saccharomyces 
producing  mycelium,  as  well  as  several  forms  of 
streptothrix. 

GROUP  III— SPIRILLA 

Among  some  of  the  most  interesting  bacteria 
to  be  found  in  the  human  mouth  are  the  group 
of  spirilla.  Tliese  organisms  differ  from  other 
bacteria  in  their  curious  morphological  form, 
consisting  of  spiral  threads  ;  the  turns  of  the 
spiral  frequently  exhibit  great  regularity  and 
beauty,  while  in  others  the  spiral  form  is  less 
well  marked,  the  turns  of  the  thread  being 
unequal  and  irregular ;  in  others,  again,  comma 
forms  are  found,  these  organisms  resembling 
an  inverted  comma,  and  no  doubt  arise  from 
the  breaking  up  of  a  spiral  thread  into  its 
component  parts. 

The  spirilla  are  closely  allied  to  the  Spiro- 
chaetes,  and  it  has  been  thought  that  the  true 
spirochaete  is  not  a  bacterium,  and  does  not 
belong  to  the  .schyzomyccs,  or  even  to  the  fungi 
at  all,  but  to  the  protozoa ;  this  view  is  usually 
held  concerning  the  spirochaeta  pallida,  the 
organism  discovered  by  Schaudin,  and  shown 
to  be  the  cause  of  syphilis.     Some  observers. 


274 


amongst  them  Miihlens  and  Hartmann  (25), 
regard  these  mouth  spirochaetes  as  closely 
related  to  the  spirochaeta  pallida,  and  claim  to 
hav'e  shown  that  the  mouth  spirochaete  possesses 
an  undulating  membrane  :  and  in  the  figures 
given  by  Miihlens  in  the  Zeitschrift  fiir  Hygiene, 
these  spirochaetes  are  so  figured  (33). 

A  large  number  of  spirochaetes  have  been 
found  in  the  mouth,  the  first  reference  to  them 
being  that  of  Lewis  in  the  Lancet.  They 
were  further  described  by  Miller  as  belonging 
to  two  varieties,  (1)  Spirochaeta  Dentium,  an 
irregular  thread  without  definite  motility,  and 
(2)  Spirillum  Sputucjenum,  a  well-marked  spiril- 
lum possessing  motility. 

In  making  films  from  ulcerative  processes 
of  the  mouth,  especially  ulcerative  stomatitis 
and  gangrenous  stomatitis,  as  well  as  from  a 
number  of  cases  of  alveolar  pyorrhoea,  large 
numbers  of  spiral-formed  organisms  are  found 
in  the  preparations.  The  spirilla  and  spirochaetes 
have  been  found  in  other  parts  of  the  body 
affected  by  gangrenous  processes — the  in- 
testinal canal,  the  genito-urinary  tract,  and  even 
the  surface  of  the  body.  Spirilla  forms  are  also 
known  as  the  infecting  cause  in  certain  fevers, 
as  for  instance  in  relapsing  fever,  in  the  West 
African  tick  fever,  and  in  a  disease  of  geese. 
Most  of  these  organisms  exhibit  the  same  general 
peculiarities,  in  that  they  do  not  grow  readily, 
and  only  a  limited  number  have  been  cultivated 
on  artificial  media. 

Very  little  attention  had  been  paid  to  the 
spirochaetes  before  Schaudin's  discovery  of  the 
spirochaeta  pallida ;  since  then  a  good  deal  of 
work  has  been  done  on  the  family  of  spirilla  and 
spirochaetes,  and  has  resulted  in  the  addition 
of  a  number  of  species  to  the  list  of  known 
spirochaetes,  as  well  as  to  the  re-naming  of  a 
number  of  species  already  known  to  exist. 

Spirochaeta  Pallida  (Treponema  Pallidum), 
This  organism  is  found  regularly  in  the  various 
lesions  of  syphilis,  both  primary  and  secondary, 
and  has  also  been  found  in  tertiary  lesions. 
The  term  treponema  has  been  applied  to  it  to 
indicate  an  organism  midway  between  the  true 
spirilla  and  the  protozoa  of  the  treponazome 
type — organisms  that  are  frankly  protozoal, 
and  show  nuclei  and  nucleoli  when  stained  by 
Romanowski's  and  Giemsa's  methods. 

The  spirochaeta  pallida  is  a  long  spirochaete 
showing  twenty  or  more  turns  in  each  individual 
thread.  So  far  the  organism  has  not  been 
grown  in  pure  culture,  although  ArnJieim  (4) 
claimed  to  have  obtained  it  in  impure  cultures. 

The  organism  stains  by  Romanowski's 
method,  and  best  by  Giemsa's  modification,  or 
better  still  by  the  silver  nitrate  method.  The 
organism  is  found,  after  special  staining  and  in 
favourable  sections,  as  large  masses  of  delicate 
spirochaetes  infecting  the  tissue  in  all  directions. 


By  taking  the  material  contauiing  the  spiro- 
chaete, as  shown  by  staining  reactions,  and  in- 
oculating monkeys,  the  primary  and  secondary 
lesions  of  syphihs  have  been  produced  ;  and  the 
spirochaete  has  been  demonstrated  not  only  in 
the  primary  lesion  at  the  seat  of  inoculation; 
but  in  the  secondary  lesions  at  a  distance.  The 
opinion  generally  accepted  at  the  present  time 
is  that  this  organism  is  the  true  cause  of  syplulis. 
Primary  lesions  have  been  produced  on  the 
conjunctivae  of  raljbits  by  inoculating  them  with 
the  serum  from  the  primary  lesion  in  monkeys. 
The  ulcer  when  examined  microscopically  is 
found  full  of  long  motile  spirochaetes. 

Since  the  discovery  of  the  organism,  con- 
siderable steps  have  been  made  in  the  direction 
of  treatment  and  early  diagnosis,  based  on 
certain  general  bacteriological  facts.  I^iagnosis 
has  been  furthered  by  Wassermann's  appUca- 
tion  of  the  method  of  Bordet — deviation  of  com- 
plement— to  the  detection  of  a  sypliihtic  virus 
in  the  blood.  This  reaction,  known  as  the 
Wassermann  reaction,  depends  upon  the  j)resence 
of  sypliilitic  virus  circulating  in  the  blood  and 
determining  the  presence  of  anti-bodies  towards 
the  spirochaetes.  Tlie  method  of  testing  is 
somewhat  complicated.  Use  is  made  of  the 
fact  that  the  specific  virus,  if  present,  absorbs 
complement  added  to  an  inactivated  haemolytic 
serum,  and  thereby  prevents  the  occurrence  of 
haemolysis.  Should  no  antigen  be  present  to 
fix  the  complement,  it  becomes  attached  to  the 
inactivated  haemolytic  serum  and  re-activates 
it ;  haemolysis  then  takes  place,  with  the  result 
that  the  fluid  in  the  tube,  instead  of  containing 
a  precipitate  of  red  cells,  becomes  uniformly 
coloured  with  the  haemoglobin  of  the  dis- 
integrated red  cells. 

The  treatment  of  the  disease  has  gained 
considerably  through  the  researches  of  Ehrlich, 
who  has  found  that  the  intra-venous  injection 
of  certain  specific  drugs  breaks  up  and  destroys 
the  organisms  in  the  tissues,  the  substance 
used,tetra-niethyl-diamino-ari3eno-benzaldehyde 
("  606  "),  being  an  organic  preparation  of 
arsenic.  As  the  immediate  result,  the  Wasser- 
mamireaction — complemental  deviation — which 
was  before  well  marked,  is  rapidly  lost,  and  only 
reappears  if  the  substance  used  has  been  in- 
sufficient to  destroy  the  spirochaeta  palUda 
infecting  the  tissues. 

The  spirochaeta  pallida  may  be  demonstrated 
in  mucous  patches  about  the  mouth  and  in 
primary  lesions  of  the  mouth,  and  has  occasion- 
ally been  found  in  gummatous  ulceration,  etc., 
of  the  palate. 

Tlie  other  spirochaetes  found  in  the  mouth 
may  be  divided  into  two  classes — ■ 

Spirochaeta  Dentium. 
Spirillum  Sputugenum. 


275 


These  two  classes  of  organisms  are  frequently 
found  associated  with  the  Ijacillus  fusiforniis, 
more  particularly  the  spirochaeta  dentiuni,  and 
it  has  been  thought  by  several  observers  that 
the  bacillus  fusiformis  and  the  spirochaete  are 
forms  of  the  same  organism  (38).  There  is  no 
doubt  that  it  is  exceedingly  difficult  to  separate 
the  various  forms  of  spirochaete  in  pure  culture. 
They  are  all  anaerobic,  and,  moreover,  will  only 
grow  in  culture  medium  containing  normal 
(unheated)  serum,  or  at  any  rate  not  heated 
above  60°  C.  The  organisms  are  so  strongly 
anaerobic  that  it  is  necessary  to  heat  the  agar 
as  well  as  the  serum  before  mixing  (agar  3, 
serum  1),  to  drive  off  tlie  entangled  oxygen. 
Shake  cultures,  Vignal  tubes,  or  deep  agar 
plates  covered  with  paraffin,  are  the  best 
methods  of  isolating  the  organism,  and  by  one 
of  these  metliods  the  organism  may  be  obtained 
in  pure  culture,  but  transference  to  other  media 
or  any  attempt  to  continue  the  cultures  is  not 
always  satisfactory ;  moreover,  there  is  a  great 
tendency  for  the  colonies  to  be  impure,  and  the 
fusiform  bacillus  and  long  threads  of  the  bacillus 
hastahs  (bacillus  necrosis),  to  be  described  later, 
are  frequently  found  mixed  with  the  spirochaetes. 
Several  definite  morphological  forms  of  the 
spirochaetes  may  be  observed  in  film  prepara- 
tions made  fiom  the  mouth,  namely  : — 

(1)  Threads  with  wavy  undulations  and 
irregular  twists,  '1  to  "2  /u  in  diameter  and  some 
7  to  8  /i  long,  the  form  corresponding  to  Miller's 
original  description  of  the  spirochaeta  dentium. 

(2)  Well-marked  spiral  forms  with  4  to  5  turns 
of  the  thread,  the  whorls  of  the  thread  being 
regular,  and  the  organism  having  pointed 
extremities,  furnished  ^\■ith  terminal  flagella. 
This  organism  corresponds  to  Miller's  original 
description  of  spirillum  sputugenum. 

(3)  A  minute  spirochaete, '  1  /x  in  diameter  and 
about  2  /x  in  length,  possessing  not  more  than 
three  to  four  turns  to  the  thread.  This  organ- 
ism is  the  one  described  by  Veszpreni  (40,  Bd. 
45,  p.  17)  as  spirochaeta  gracilis. 

All  these  spirochaetes  are  Gram-negative,  and 
the  staining  is  best  carried  out  by  Leishman's 
modification  of  Romanowski's,  or  with  dilute 
carbol-fuchsin  for  some  little  time.  If  staining 
with  fuchsin,  it  is  better  to  clear  the  films 
thorouglily  with  alcohol  and  ether  and  1% 
acetic  acid  before  staining. 

(4)  Comma-shaijed  bacUli,  resembling  in  many 
respects  the  second  form  of  Miller's  spirillum 
sputugenum.  This  organism  has  recently  been 
grown  in  pure  cultures  by  Miihlens  (34),  who 
claims  that  it  is  a  distinct  species. 

(."))  The  E  bacillus  of  Miller,  an  organism  of 
spirillum  form,  non-motile,  and  frequently  found 
in  carious  dentine,  and  growing  easily  on 
potato -gelatine. 

Of  thes:'  spirochaetes,  the  last  only  is  aerobic, 


the  other  four  being  anaerobic.  The  spirochaeta 
dentium  has  been  grown  in  pure  culture  by 
Miihlens  and  Hartmann  (25).  wlio  describe  the 
cultures. 

They  were  unaljle  to  obtain  any  growth  on 
the  ordinary  culture  media,  unless  serum  was 
added  and  air  rigorously  excluded.  Inocula- 
tion experiments  carried  out  with  pure  cultures 
produced  no  lesions  in  animals.  The  colonies 
are  somewhat  typical  in  the  depths  of  the 
serum-agar,  being  small,  circular,  slightly  granu- 
lar, and  greenish,  and  exhibiting  as  a  rule  a 
tangled  mass  of  threads,  which  only  later  show 
a  distinct  spirochaetal  form.  The  threads  tend 
to  show  irregular  staining,  and  may  be  grouped 
in  masses,  in  which  the  spirochaetal  form  is 
almost  lost. 

The  spirillum  sputugenum,  except  in  its 
comma-shaped  variety,  does  not  seem  to  have 
been  grown  l)y  either  of  these  observers  ;  but 
more  recently  Miihlens,  in  the  paper  referred 
to  above,  gives  particulars  of  an  organism  that 
he  has  obtained,  which  closely  resembles  and 
probably  is  identical  with  this  comma  form. 

The  E  bacillus  of  Miller  was  obtained  by 
the  writer  in  pure  culture  some  time  ago,  by 
the  use  of  potato-agar,  and  was  at  first  thought 
to  be  the  spirochaeta  dentium ;  but  the  later 
work  of  Miihlens  and  Hartmann,  whicli  to 
some  extent  the  \mter  has  been  able  to 
confirm,  has  afforded  evidence  that  this  parti- 
cular spirillum  belongs  to  the  type  described 
by  Miller  as  the  E  bacillus.  The  organism, 
like  the  others,  is  Gram-negative,  and  in  old 
cultures  grows  out  into  quite  long  threads 
and  spirochaetes,  as  well  as  spirilla,  and  shows 
curious  enlarged  cocci-like  bodies  in  the  course 
of  the  thread,  closely  resembling  the  so-called 
arthrospores  descriljed  by  Pfeiffer  in  the  cholera 
bacillus.  Inoculations  with  this  organism  were 
found  to  be  distinctly  pathogenic  for  guinea- 
pigs,  and  the  orgamsm  was  obtained  in  pure 
culture  from  the  bone-marrow  of  the  femur, 
but  not  from  the  blood. 

Tliere  is  consideraljle  difficulty  at  the  present 
time  in  separating  the  various  groups  of  spiro- 
chaetes and  spirilla  into  their  proper  genera,  and 
it  will  be  necessary  to  refer  to  them  again  in 
dealing  with  the  next  group  of  organisms, 
amongst  which  comes  the  bacillus  fusiformis. 
A  considerable  amount  of  further  research 
on  the  mouth  spirochaetes  is  required  before 
one  can  regard  tlie  several  species  as  being 
satisfactorily  separated.  For  further  parti- 
culars, as  well  as  tiu'  literature  on  the  sul)ject, 
see  the  papers  of  Miihlens  and  Hartmann,  and 
Veszpreni. 

Anaerobic  Bacilli 

In  addition  to  the  spirochaetes  just  described, 
which  are  obligatory  anaerobes,  two  organisms 


!276 


of  fairly  common  occurrence  in  the  mouth  are 
obligatory  anaerobes,  whilst  a  number  of  others, 
so  far  ungrowni,  probal)ly  belong  to  the  group 
as  well. 

Cliief  amongst  the  anaerobic  bacilli  that  have 
been  cultivated  on  artificial  media  with  success, 
are  the  liacillus  fusiformis  and  bacillus  hastalis. 
In  addition  to  these,  the  bacillus  perfringens, 
found  in  the  alimentary  tract,  has  been  de- 
scribed as  occurring  in  the  mouth,  but  is  more 
common  in  the  intestinal  canal  (47). 

Bacillus  Fusijormis. — As  has  been  premised 
in  discussing  the  spirochaetes  and  spirilla  of  the 
mouth,  the  bacillus  fusiformis  is  commonly 
found  associated  with  the  spirillum,  particularly 
in  infective  processes  of  a  gangrenous  nature, 
namely,  gangrenous  stomatitis,  ulcerative  stoma- 
titis, ulcerative  gingivitis,  and  Vincent's  angina. 


Fig.  384. — Bacillus  fusiformis  in  pus  with  spirochete 
dentium,  gentian  violet,     x  1000. 

The  organism  is  a  diplobacillus,  frequently 
with  tapered  ends,  the  two  halves  of  the  bacilU 
being  roughly  triangular  with  their  bases  in 
apposition — not  at  all  unlike  the  sheath  form 
of  the  diphtheria  bacillus,  but  much  larger.  It 
does  not  stain  by  Gram's  method,  although  if 
the  decolorization  is  carried  out  very  quickly, 
a  certain  amount  of  stain  may  be  retained, 
more  especially  in  smears  made  from  infective 
processes  in  the  mouth,  which  are  full  of  mucin 
and  albumin. 

Tlie  organism  may  be  as  much  as  1  /i  in 
■vsidth  in  the  widest  part,  tapering  off  to  fine 
pointed  ends.  In  sections  of  tissues  undergoing 
an  ulcerative  process  the  bacilli  are  found  in 
the  deeper  layers,  together  with,  but  in  advance 
of,  the  spirochaetes.  Wlien  cultivations  are 
made  on  the  ordinary  laboratory  media  under 


aeroljic  or  anaerobic  precautions,  no  growth 
takes  place.  When,  however,  serum-agar  is 
u.sed,  under  strict  anaerobic  precautions,  growth 
of  colonies  of  the  bacillus  fusiformis  takes 
place,  together  with  a  small  number  of  the 
spirochaetes.  The  colonies  are  frequently  im- 
pure, and  show  a  mixture  of  fusiform  baciUi 
and  long  threads — doubtless,  involution  forms 
of  the  spirochaetes. 

From  the  constant  occurrence  of  curved  and 
spiral  threads  with  the  bacillus  fusiformis, 
Turnecliffe  and  others  have  been  led  to  suppose 
that  the  fusiform  bacillus  and  the  spirochaete 
^vere  identical.  On  the  other  hand,  Miihlens 
and  Hartmami,  who  isolated  the  spirochaete 
by  the  serum-agar  method,  were  able  to  com- 
pare the  growth  ^^•ith  bacillus  fusiformis,  a 
pure  culture  of  which  had  been  supplied  to 
them  by  Ellermann,  and  the  organisms  showed 
very  chstinct  differences  both  in  their  colonies 
and  in  their  cultural  characters. 

The  cultural  characters  of  the  bacillus  fusi- 
formis are  mainly  of  the  negative  type.  The 
organism  does  not  grow  unless  serum  is  added ; 
it  \\ill  grow,  however,  on  glucose-agar  with  a 
slight  addition  of  serum,  or  in  milk  broth,  or 
in  carbo-hydrate  peptone  water  if  serum  has 
been  added,  but  only  under  anaerobic  conditions. 
Xo  development  of  acid  takes  place.  In  older 
cultures  the  organism  tends  to  grow  out  into 
longish  threads,  these  threads  sho\nng  curious 
transverse  and  dotted  markings  %\hen  stained 
with  methylene  blue  or  Leishman's  stain.  In 
addition,  curious  rounded  swollen  forms  appear 
in  the  course  of  the  thread,  and  these  particular 
forms  may  often  be  observed  in  impure 
cultures,  when  streaks  are  made  on  ordinary 
agar  from  idcerative  stomatitis. 

If  organisms  other  than  the  anaerobes  are 
present,  particularly  obligatory  aerobes,  the 
oxygen-loving  bacteria  apparently  use  up  so 
much  of  the  oxygen  in  the  immediate  vicinity 
that  a  limited  development  of  the  anaerobes 
takes  place.  This  may  be  well  seen  in  making 
a  broth  culture  from  a  case  of  ulcerative 
stomatitis,  when  at  the  end  of  two  or  three 
days,  long  threads  and  various  other  involution 
forms  of  anaerobic  bacteria  may  be  met  ^^•ith, 
forming  a  thick  deposit  at  the  bottom  of  the 
tube.  Attempts  to  separate  these  by  the 
ordinary  methods  of  aerobic  process  never  result 
in  the  growth  of  the  anaerobic  organisms. 

In  these  broth  cultures  an  exceedingly 
foetid  smell  is  produced,  and  various  observers 
who  have  dealt  with  the  bacillus  fusiformis — 
Veszpreni  (40.  Bd.  44.  p.  G60),  Abel  (1)  and 
Ellermann  (15) — all  agree  about  the  relation  of 
this  foetidsmell  to  cultures  of  bacillus  fusiformis. 
Perhaps  the  best  method  of  isolating  the 
organism  is  by  the  use  of  Vignal  tubes,  when 
the  individual  colonies  may  be  selected.     The 


277 


colonies  of  the  bacillus  fusiformis  in  the  depth 
of  the  medium  are  of  a  disc-like  form,  biconcave 
in  shape,  yellowish,  finely  granular,  and  with  a 
somewhat  darker  centre,  the  colonies  of  the 
spirochaetes  being  greenish  and  non-striated, 
and  tending  to  send  out  processes  into  the 
surroundiiig  media. 

The  bacillus  fusiformis  and  the  spirochaetes 
are  always  to  be  found  in  ulcerative  stomatitis, 
and  in  Vincent's  angina;  from  their  constant 
association  with  each  of  these  diseases,  and  from 
their  position  histologically  in  the  depths  of 
the  tissues,  there  seems  to  be  little  doubt  that 
the  organisms  themselves  are  concerned  in  the 
tissue  necrosis.  So  far,  however,  the  various 
observers  are  not  in  agreement  as  to  the 
pathogenicity   of   these   organisms. 

Miihlens  and  Hartmann,  working  with  pure 
cultures,  were  unable  to  obtain  pathogenic 
effects  by  inoculating  large  quantities  into 
laboratory  animals.  On  the  other  hand,  Eller- 
mann  and  Veszpreni  both  succeeded  in  pro- 
ducing very  definite  pathological  results,  but 
Miihlens  and  Hartmann  are  inclined  to  regard 
the  pathogenic  effect  as  due  to  an  admi.xture 
with  other  organisms.  There  is  no  doubt 
that  the  bacillus  fusiformis  is  concerned  with 
tissue  necrosis;  in  several  rabbits  that  the 
writer  has  inoculated  with  cultures  containing 
the  bacillus  fusiformis  and  the  spirochaete  in 
large  numbers,  together  with  certain  strepto- 
cocci, which  are  exceedingly  difficult  to  eliminate 
from  the  cultures,  he  has  produced  much  greater 
pathogenic  effects  than  when  a  pure  culture 
of  either  the  streptococcus  or  bacillus  fusiformis 
itself  has  been  inoculated. 

If  the  pus  from  a  case  of  ulcerative  stoma- 
titis, or  the  triturated  necrosed  tissue,  is  inocu- 
lated subcutaneously  into  an  animal,  patho- 
logical results  follow,  the  tissue  necrosis  often 
extending  over  very  wide  areas ;  in  one  of  the 
writer's  rabbits  the  abscesses  spread  from  the 
cricoid  cartilage  to  the  pubes,  and  into  both 
axillae. 

Bacillus  Ha-stalis  {Bacillus  Necrosis). — This 
organism  is  closely  related  to  the  bacillus  fusi- 
formis, and  may  be  obtained  in  pure  culture 
by  the  same  serum  method.  It  is  strictly 
anaerobic  and  serophile,  and  forms  long  threads, 
but  without  the  characteristic  diplobacillary 
form  of  the  bacillus  fusiformis.  The  threads  are 
very  long  and  pointed,  and,  as  witii  bacillus 
fusiformis,  an  unpleasant  foetid  smell  is  pro- 
duced. The  organism  is,  no  doubt,  similar  in 
all  res])ects  to  that  described  by  many  observers 
as  bacillus  necrosis,  and  found  in  parts  of  the 
body  other  than  the  mouth.  ■  It  has  been  de- 
scribed in  diseases  of  cattle,  by  Vogcs  (41), 
and  in  man,  in  lung  gangrene,  necrotic  con- 
ditions of  the  liver,  etc.  (27). 

The  organism  belongs  to  the  class  of  anaerobic 


thread-forming  bacteria — a  class  as  yet  ill- 
deiuied,  and  containing  many  organisms  that 
have  not  received  sufficient  investigation. 

The  best  method  of  demonstrating  these 
necrotic  bacteria  in  diseased  organs  is  l>y  means 
of  smear  preparations  made  from  a  small  piece 
of  necrosed  tissue,  and  stained  by  Leishman's 
modification  of  Romanowski's  method.  The 
diagnosis  of  diphtheritic  membrane  or  Vincent's 
angina  may  be  thus  easily  made,  but  it  must 
not  be  forgotten  that  the  fusiform  bacillus 
may  often  be  found  associated  with  true 
diphtheria. 

These  anaerobic  organisms  already  described 
— bacillus  fusiformis,  bacillus  hastahs,  and  the 
spirochaetes — occur  in  the  mouths  of  man  in 
various  races  :  the  writer  has  obtained  them 
from  the  mouths  of  men  of  the  native  races 
of  Central  Africa,  of  India,  and  of  China ;  and 
recently  Gustav  Meldorf  (31),  on  examining 
the  mouths  of  persons  in  Greenland  suffering 
from  ulcerative  stomatitis,  has  described  organ- 
isms that,  from  their  morphology,  are  evidently 
those  under  discussion. 

GROUP  IV— STREPTOTHRICAE 

The  streptothrix  group  comprises  a  series  of 
organisms  liiglier  in  the  scale  than  those  already 
considered,  and  coming  intermediate  between 
the  yeasts  or  blastomyces,  and  the  fission- 
fungi  or  bacteria,  the  schizomyces. 

The  characteristics  of  the  group  are  increased 
complexity  of  form,  the  filamentous  mycelium 
showing  true  brandling.  The  ends  of  the 
threads  of  the  mycelium  undergo  differentia- 
tion into  cocci-like  bodies,  or  gonidia,  which 
in  certain  groups  contain  a  quantity  of  dark 
pigment. 

The  grow-th  of  the  whole  group  is  character- 
istic. The  colonies  are  cartilaginous  and  tough, 
and  as  they  become  old  tend  to  crater-like 
form,  splitting  across  and  showing  various 
stages  of  pigmentation,  from  chalky-wliite 
through  various  shades  of  yellow  and  pink  to 
dark  brown.  Some  members  of  the  group 
cau.se  distinct  staining  of  the  media  in  which 
they  are  growing,  whUst  others  produce  no 
such  change.  The  white  or  coloured  powder 
on  the  surface  of  the  colonies,  which  may  be 
easily  scraped  off,  contains  the  cocci-like  bodies, 
which,  when  sown  on  the  surface  of  nutrient 
media,  rapidly  develop  into  the  tangled  myce- 
lium. As  the  mycelium  becomes  old,  it  under- 
goes gradual  fragmentation  into  portions  bearing 
a  morphological  resemblance  to  the  bacteria. 

A  number  of  members  of  the  grouj)  are  patho- 
genic, and  a  few  retain  the  stain  when  stained 
by  the  tubercle  bacillus  method,  and  are  termed 
acid-fast.  In  not  a  few  instances  they  have 
been  showii  to  be  the  infecting  organism  in 


278 


a  disease  of  the  lung  closely  resembling  pulmon- 
ary tuberculosis. 

Tlie  streptothrix  adinomyces,  or  ray  fungus, 
the  first  organism  of  this  group,  produces  the 
well-known  disease  of  the  jaw  known  as  actino- 
myces,  or  sometimes  actinomycosis.  The 
disease  is  commoner  in  the  lower  animals  than 
in  man,  and  produces  the  so-called  "  woody 
tongue  "  in  cattle,  and  when  affecting  the  bone 
causes  enormous  swelling,  and  tunnelling  of  the 
hypertrophied  mass. 

In  pus  from  a  case  of  actinomyces,  the  strepto- 
thrix may  be  found  in  the  form  of  small  granules 
of  golden  yellow  or  lighter  yellow  colour,  about 
•5  of  a  millimetre  in  diameter.  Inspection  with 
the  microscope  shows  these  granules  to  be  com- 
posed of  tangled  masses  of  threads  (mycelium) 
exhibiting  true  branching ;  the  outer  ends  are 
thickened  and  club-shaped. 

The  organism  is  supposed  to  gain  entrance  to 
the  mouth  and  soft  tissues  through  the  medium 
of  one  of  the  cereals,  and  in  many  instances  an 
&\vn  of  barley  has  been  discovered  in  the 
centre  of  the  tumour.  The  disease  often  makes 
its  first  appearance  in  some  organ  or  gland 
associated  with  the  alimentary  tract,  and  when 
once  established  is  exceedingly  difficult  to 
eradicate. 

The  true  streptothrix  actinomyces  grows  best 
anaerobically,  and  two  types  are  described — • 

Streptothrix  Actinomyces  Bovis. 
Streptothrix  Actinomyces  Hominis. 

It  is  probable  that  the  two  organisms  are  closely 
related.  The  organism  stains  with  the  ordinary 
anihne  dyes,  and  best  by  Gram's  method, 
Weigert-Gram  being  the  best  stain  for  tissue 
preparations.  It  grows  readily  on  the  ordinary 
laboratory  media,  forming  gelatinous  colonies, 
which  turn  yellow  after  four  or  five  days ;  and 
it  presents  no  difficulty  in  recognition.  (See 
Chapter  LI,  p.  767.) 

A  large  number  of  species  of  the  genus  strepto- 
thrix are  known,  and  some  of  them  occur  in  the 
human  mouth ;  amongst  these,  one  first  de- 
scribed by  the  writer  in  the  Transactions  of  the 
Odontological  Society,  1899,  as  cladothrix  huccalis, 
was  found  by  him  later  to  be  a  true  streptothrix. 
This  organism  is  often  present  in  the  mouth, 
and  differs  from  a  number  of  other  strepto- 
thricae  in  its  cultural  peculiarities.  It  stains 
by  the  usual  methods,  and  by  Gram's  method. 
It  is  not  acid-fast  to  carbol-fuchsin.  Filaments 
of  this  organism  may  be  ob.served  in  preparations 
from  the  white  deposit  found  along  the  gum 
margins  in  neglected  mouths,  where  its  fila- 
ments are  associated  with  an  organism  to  be 
described  later,  namely,  crenothrix  polyspora. 
The  streptothrix  buccalis  produces  well-marked 
gelatinous    white    colonies    on    agar,    but    no 


staining  of  the  medium  occurs ;  the  colonies 
very  soon  become  covered  with  a  white  flour-like 
fluorescence.  So  far  it  has  not  been  found 
pathogenic  for  animals.  The  cultures  give  off 
a  characteristic  smell,  much  like  that  of  a  damp 
cellar. 

A  number  of  other  streptothricae  have  been 
found  in  the  mouth — some  of  them  isolated  from 
bone  and  gum  inflammation.  The  writer  has, 
on  several  occasions,  found  a  streptothrix  closely 
related  to  the  streptothrix  actinomyces,  but 
differing  from  it  in  cultural  characters,  in  acute 
inflammation  of  the  bone  of  the  mandible. 

Foulerton  (18)  made  a  study  of  the  strepto- 
thrix group,  and  describes  twenty-five  species 
in  his  original  paper,  some  of  them  pathogenic. 


Fig.  385. — Streptothrix  buccalis,  24  hrs.  agar. 
Gram.      X   1000. 

Amongst  these,  two  had  been  obtained  from 
dento-alveolar  abscesses.  For  the  full  de- 
scription of  these  species,  the  cultural  reactions, 
and  epitome  of  the  literature  to  that  date,  as 
well  as  the  micro-photographs  of  the  organism, 
the  student  is  referred  to  the  original  paper. 

GROUP  V— BLASTOMYCES 

The  blastomyces,  or  yeasts,  form  a  group  of 
organisms  higher  in  the  scale  than  the  strepto- 
thricae. The  organisms  develop  by  budding,  one 
or  more  secondary  cells  being  formed  from  the 
main  cell ;  and  in  most  species  of  saccharomyces 
definite  mycelial  formation  takes  place,  the  myce- 
lium showing  a  roughly  articulated  form,  closely 
resembling  the  hyphomyces,  or  mould  fungi. 
The  organisms  are  all  comparatively  large,  being 
10  /J,  or  more  in  diameter  ;  they  are  round,  oval, 
or  lanceolated,   and  when  stained  with  poly- 


279 


chromatic  methylene  lihie  show  a  distinct 
nucleus  in  the  centre  taking  a  red  colouration, 
and  suriounded  by  Ijlue  c\'loplasni  in  which 
are  a  nuniher  of  finely  refractile  granules. 

The  chief  representatives  of  this  group  associ- 
ated with  the  pathology  of  the  mouth  are  the 
saccharomycrs  albicans,  oidium  albicans,  or  so- 
called  thrush  fungus,  and  sacclmroinycef!  r/ingivae. 
The  first  organism  is  an  occasional  inliabitant 
of  healthy  mouths,  and  the  writer  has  met  with 
it  in  about  one  per  cent  of  unclean  mouths.  It 
is  not  common,  and  is  rarely  found  in  "pyor- 
rhoea alveolaris  ",  or  ah'eolar  osteitis. 

Tlie  other  saccharomyces  is  occasionally 
found  in  discharge  of  pus  along  the  gum  margins  ; 
it  has  many  of  the  cultural  characteristics  of  the 
saccharomyces  neoformans  of  San  Felice,  from 


•••. 


4» 


Fig.  380. — Saccharomyces  neoformans,  24  hrs. 
glucose  agar.  Gram,      x  1000. 

which  organism,  however,  it  differs  in  several 
important  respects,  and  may,  therefore,  be 
considered  to  be  a  species  esjiecially  related  to 
tlie  mouth. 

Saccharomyces  Albicans  (Oidium  Albicans, 
Thrush  Fungus). — The  growth  of  this  organism 
on  artificial  media  is  exceedingly  characteristic 
Its  colonics  form  delicate  rayed  masses  with  a 
minute  central  point,  the  fine  filaments  radiating 
regularh-  from  the  centre.  It  stains  by  Gram's 
method,  and  by  the  ordinary  aniline  dyes. 

When  examined  microscopically,  the  organ- 
ism is  found  to  consist  of  an  irregular  mycelium 
having  a  large  munber  of  joints  ;  the  individual 
joints  are  somewhat  elongated,  tajjered,  and 
many  /jl  in  width,  and  at  the  ends  show  a  slightlj^ 
protruding  rim.  This  portion  of  the  cell  takes 
on  a  deeper  stain  than  the  other  part  of  the 
organism. 


Tlie  organism  grows  fairly  well  on  ordinary 
laboratory  media,  but  nuich  the  best  results 
are  obtained  on  media  containing  sugar,  glucose, 
or  lactose,  both  of  which  it  rapidly  ferments. 
It  is  slightly  pathogenic  for  the  low'cr  animals, 
and  in  man  grows  with  greatest  frequency  in 
the  terminal  stage  of  certain  debilitating  dis- 
eases, such  as  pulmonary  tuberculosis,  causing 
a  white  membrane  in  the  mouth.  In  other 
cases,  in  underfed  children,  it  may  produce  a 
white  membrane  in  the  fauces  and  buccal 
mucous  membrane,  closely  simulating  the 
membrane  of  diphtheria.  A  coverslip  prepara- 
tion will  rapidly  clear  up  the  diagnosis. 

The  whitish  membranous  deposit  produced 
by  the  saccharomyces  albicans  must  not  be 
confused  with  the  white  necrotic  patches 
associated  with  ulcerative  and  gangrenous 
stomatitis,  in  which  the  bacillus  fusiformis 
and  spirochaeta  sputugemim  are  invariably 
found. 

Saccliaromyces  Gingivae. — This  organism  is  a. 
large,  oval,  lanceolated,  or  rounded  yeast, 
frequently  forming  defiiute  mycelial  filaments, 
which  are  often  found  in  smears  from  the 
margins  of  hypertrophied  gums.  The  organism 
grows  best  on  maltose,  or  lactose-agar.  It  does 
not  liquefy  gelatine,  and  on  the  surface  of  agar 
and  gelatine  containing  one  per  cent  of  maltose 
produces  a  coarsely  granular  growth.  The 
individual  colonies  are  rounded,  opaque,  with 
sharply  defined  edges,  soft  in  consistency,  and 
giving  a  granular  appearance  when  mixed  with 
water  for  the  purpose  of  making  coverslip 
preparations.  This  yeast  is  frequently  patho- 
genic ;  when  isolated  from  the  gum  margins, 
and  inoculated  in  pure  culture  into  animals,  it 
may  produce  secondary  growths  in  various 
parts  of  the  animals"  bodies,  notably  in  the 
spleen,  kidney,  and  lung.  The  appearance  of 
these  growths  is  highly  characteristic,  and 
closely  resembles  sarcoma.  Tlie  pathological 
condition  of  the  mouth  w  ith  which  the  organism 
itself  is  most  frequently  associated  is  hyper- 
trophy of  the  gums,  and  one  particular  form  of 
hypertrophic  gingivitis  is  probably  caused  by  it. 
It  gives  the  ordinary  staining  reactions  of  the 
yeast,  particularly  with  polychrome  methylene 
blue,  or  Leishman's  modification  of  Romanow- 
ski's  stain,  a  well  marked  chromatin  .staimng 
being  exhibited  by  the  latter  method.  For  the 
cultural  characters  see  the  Transactions  of  the 
Odontological  Society,  1908. 

Certain  other  members  of  the  saccharomyces 
family  are  occasionally  found,  but  are  non- 
pathogenic. Chief  amongst  them  is  a  yeast 
producing  bright  red  colouration,  as  well  as  one 
producing  a  pink  colour,  closely  resembling  the 
ordinary  pink  torula.  Both  of  these  organisms 
are  of  little  interest,  except  for  their  pigment 
production. 


280 


GROUP  VI— LEPTOTHRICAE 

Zoph  defines  as  a  leptothrix  "  thread-like, 
filamentous  forms  showing  distinct  differentia- 
tion between  the  two  ends,  one  end  of  the  thread 
being  apparently  modified  for  attachment,  and 
the  other  forming  a  variety  of  arthro-spores  or 
gonidia." 

The  so-called  leptothiix  epidermidis  alba,  is  a 
large  bacillus  growing  out  into  threads.  Miller's 
original  description  of  the  leptothrix  also  in- 
cluded definite  bacterial  forms,  without  any 
differentiation  into  a  higher  type  of  cryptogam. 
Tlie  term  '"  Leptothrix  "  is  used  loosely,  as 
synonymous  with  any  thread  form,  and  has 
been  appUed,  therefore,  to  the  thread  form  of  any 
bacterium.  Although  it  is  not  uncommon  to 
find  '"  leptothrix  of  the  mouth",  "  the  leptothrix 
of  tooth  decay  "',  cited  as  definite  entities,  such 
an  entity  has  no  more  real  existence  than  any  j 
of  the  category  of  heraldic  beasts. 

If  stained  preparations  are  made  from  the 
white  material  found  adhering  to  the  necks  of 
the  teeth  in  some  mouths  (particularly  those 
where  there  is  a  good  deal  of  caries  but  no 
definite  gum  suppuration),  or  from  the  surface  | 
of  artificial  dentures,  or  even  from  scrapings  | 
from  the  tongue,  a  large  mass  of  threads  may 
frequently  be  seen.  These  threads  stain  by  i 
Leishman's  method,  and  show  a  general  simi- 
larity. If.  as  Leon  Williams  first  pointed  out, 
considerable  care  is  exercised  in  making  the 
films,  and  the  material  to  be  examined  is  sus- 
pended in  distilled  water  instead  of  being 
smeared  on  to  the  slide  or  coverslip,  a  certain 
amount  of  structure  may  be  seen,  which  in  the 
ordinary  method  of  making  smears  is  lost 
through  the  breaking  up  of  the  threads.  In 
ordinary  preparations  stained  with  either 
gentian-violet  or  Leishman's  stain,  curious 
felted  masses  of  threads  may  be  seen,  a  number 
of  these  threads  being  surrounded  by  a  mass 
of  cocci-like  bodies  ;  and  by  careful  focussing 
the  threads  may  be  seen  pas.sing  through  the 
centre  of  the  mass.  If  the  material  is  rather 
more  broken  up,  and  Leishman's  stain  (especi- 
ally) made  use  of,  a  large  number  of  morpho- 
logical forms  of  bacteria  are  seen.  These  may 
be  grouped  as  follows — 

Irregular  cocci-like  bodies,  diplo-  and  single 
cocci  of  various  sizes,  staining  not  a  deep  blue 
but  a  faint  violet  with  the  reagent  used ;  a 
number  of  bacilH,  diplobacilli,  and  various- 
sized  threads,  some  of  them  quite  fine  (not  more 
than  -2  /x  in  diameter),  others  very  much  larger, 
up  to  1-5  /x  (the  bacilli  may  show  irregular 
staining,  well-marked  purplish  dots  highly 
suggestive  of  a  chromatin  staining  being  observ- 
able in  their  interior) ;  long  articulated  threads, 
some  of  them  very  large,  and  showing  in  their 
interior  numerous  darkly  stained  bodies. 


Wlien  stained  by  Gram's  method,  most  of 
the  bacilli  and  cocci-like  bodies  remain  un- 
stained ;  the  threads  take  a  faint  stain,  but  the 
internal  structure  stains  deeply — in  all  proba- 
bility it  decolorizes  with  greater  difficulty  than 
the  rest  of  the  organism,  for  if  the  decolorization 
is  carried  too  far,  this  curious  punctate  appear- 
ance is  lost. 

The  threads  do  not  show  definite  branching, 
but  have  the  appearance  of  an  internal  struc- 
ture consisting  of  small  cUvisions  passing  across 
the  thread  at  right  angles  to  its  long  axis. 
Practically  all  varieties  of  the  schizomyces  mor- 
phology are  seen  in  such  a  preparation  ;  this  led 
Vicentini  to  the  remarkable  supposition  that  all 
micro-organisms  of  every  known  species,  in- 
cluding of  course  the  tubercle  bacilli  and  all 
other  pathogenic  forms,  were  only  fragments  of 
the  organism  that  he  termed  "  Leptothrix 
racemosa  ". 

Prom  careful  examination  and  consideration 
of  a  number  of  preparations,  and  comparison 
of  the  preparations  \\ith  photographs  and  draw- 
ings of  the  liigher  bacteria  derived  from  other 
sources,  particularly  water,  the  writer  has  come 
to  the  conclusion  that  the  organism  producing 
this  wonderful  medley  of  morphological  forms  is 
a  variety  of  the  group  of  bacteria  described  by 
Cohn,  and  figured  by  Zoph,  as  crenothrix  poly- 
spora.  This  organism  has  the  same  curious 
irregular  threads,  which  seem  to  proceed  from  a 
central  parent,  the  internal  portion  of  the  thread 
showing  a  large  number  of  cocci-like  bodies ; 
and  the  apparent  branching  is  produced  by  the 
development  of  these  cocci-like  bodies  into 
threads,  which  undergo  transverse  fragmen- 
tation, become  .spht  off,  and  hence  form  the 
various  morphological  types. 

Rullermann  (37)  gives  figures  of  the  crenothrix 
polyspora,  according  to  Zoph,  and  also  figures  of 
a  crenothrix  obtained  from  a  waterworks  in 
Bavaria.  The  photograph  gives  the  exact 
morphological  type  that  is  met  «ith  in  a  number 
of  mouth  preparations — the  jointed  threads,  the 
cocci-like  bodies  situated  in  the  interior  of  the 
threads,  and  the  curious  packets  of  threads 
sprouting  from  the  centre  ;  all  of  which  may  be 
met  with  in  the  smears  made  from  the  normal 
human  mouth.  If  comparison  is  made  of  the 
illustrations  given  by  Leon  Williams  and 
Vicentini,  as  well  as  the  earlier  diagrams  given 
by  Miller  of  the  leptothrix  innominata  and 
leptothrix  gigantia  of  the  mouth,  and  of  lepto- 
thrix buccalis,  in  each  case  close  similarity  to 
the  diagram  of  Zoph  and  the  photographs  of 
Rullermann  is  observed.  So  far,  the  organism 
has  not  been  grown,  and  it  is  impossible  from 
merely  stained  preparations  from  the  mouth 
to  be  absolutely  certain  as  to  its  identity,  but 
there  is  little  doubt  that  the  curious  morpho- 
logical forms  that  have  been  described  as  the 


281 


leptothrix    racemosa    belong    to    the  group  of 
crenothrix  polj-spora  (Cohn). 

K.  W.  G. 

BIBLIOGRAPHY 

(1)  Abel.      Cenl.  far  Bakt.,  Abt.  1,  Bd.  XXIV,  1898. 

(2)  Andrews   &  Horder.     Lancet,   Sept.    15,    1906 

p.  708. 

(3)  ArkiiVY.      Vierteljahrssch.   jiXr   Zahnheilk.,    1893, 

Heft  11. 

(4)  Arnheim.     Berl.  Klin.  Woch.,  1909. 

(5)  AXENFELD.      Archiv  jur  Opklhalm.,  1896,  Bd.  42. 

(6)  Babes.     Zeits.  fiir  Hygien.,  1889,  Bd.  V. 

(7)  Bayos.     Proc.  Hoy.  .Sor.  Met!.  (Path.  Sec),  1912. 

(8)  Bayon.     Jour.  Soc.  Trop.  Medicine,  1912. 

(9)  Bulloch.     Proc.  Roy.  Soc.  Med.,  1910,  Vol.  Ill, 

p.  75.     (Discussion  on  Vaccine  Therapy.) 

(10)  Burger,  Leo.     Cent,  jur  Bakt.,  Bd.  41,  p.  414. 

(11)  Cautley.     L.G.B.  Reports,  1894. 

(12)  De  Simoni.      Vfficiale  Samlaro,  1899. 

(13)  DoBRZYNicKi.     C'en^/«r-BaA(.,  Bd.  21,  p.  835. 

(14)  Dudgeon.     Jour,  of  Hyi/iene,  1911,  p.  137. 

(15)  Ellermann.     Cent,  fur  Bakt.,  Bd.  38,  p.  383. 

(16)  Eyre.     Brit.  Med.  Jour.,  Nov.  4,  1899. 

(17)  Fehleisen.     KoUe    &    Wassermann's   Harulbuch 

der  pathogenen  Mikroorganismen,  Bd.  Ill,  pp. 
304-5. 

(18)  FouLERTON.     Trans.  Path.  Soc,  1902,  p.  50. 

(19)  FrXnkel.      Zeits.  fur  Klin.  Med.,  1886,  Bd.  XI, 

Heft  5  and  6. 

(20)  Freund.     hiaugiiral  Dissertation,  Freiburg,  1898. 

(21)  GoADBY.     Layicet,  Jlarch  9,  1907. 

(22)  GoADBY.     Proc.  Roy.  Soc.  Med.,   1910,  Vol.  Ill, 

p.  85.     (Discussion  on  Vaccine  Therapy.) 

(23)  GoADBY.     Hunterian  Lecture.      Lanct'^  March  1 1, 

1911. 


(24)  Graham-S>uth.      Jour,     of    Hygiene,    Vol.    IV, 

1904,  p.  289. 

(25)  Hartmann.     Deutsch.  Med.  Woch.,  1906,  No.  20. 

(26)  H.AUSER.     Munchen.  Med.   Woch.,  Bd.  39,  1902, 

p.  103. 

(27)  KoLLE   &   Wassermann.     Handbuch   der   patho- 

genen Mikroorganismen,  Vol.  II,  p.  699. 

(28)  Lewis.     Jour,  of  Path.  <fc  Bact.,  1911,  p.  41. 

(29)  LiNGELSHKiM.       Zeits.    jiir    Hygien.,    Bd.    X,    p. 

331. 

(30)  MacConkey.     Jour,  of  Hygiene,  Vol.  V,  p.  341. 

(31)  Meldorf.     Cent.  jUr  Bakt.,  Bd.  58,  p.  635. 

(32)  MUHLENS.     Deutsch.  Med.  Woch.,  1906,  No.  20. 

(33)  MiJHLENS.     Zeils.  jttr  Hygien.,  1906,  Bd.  55. 

(34)  MtiHLENS.     Cent,  jur  Bakt.,  Abt.  1,  Orig.  Bd.,  pp. 

523-48. 

(35)  RiTTER.     Verl.d.X.versj.Kinderheilk,\\iesha.dein, 

1894. 

(36)  RosENBACH.     KoUe   &  Wassermann's  Hamlburk 

der  pathogenen  Mikroorganismen,  Bd.   Ill,  pp. 
304-5. 

(37)  RuLLERMANN.      Cent,  far  Bakt.,  Abt.  1 1,  Bd.  XX, 

pp.  98-9. 

(38)  TuRNECLiFFE.     Jour,      oj      Injectious     Diseases, 

Vol.  Ill,  1906. 

(39)  Uhthoff.     Archiv  jUr  Ophtkalm.,  1896,  Bd.  42. 

(40)  Veszpreni.     Cent,  jur  Bakt. 

(41)  VoGES.     Cent,  jiir  Bakt.,  1902,  p.  136. 

(42)  W.ASHBOURN.      Jour.    Path,    and    Bad.,     1894-5, 

Vol.  Ill,  p.  214. 

(43)  Washbourn.     Jour.  Path,  and  Bact.,    1898,  Vol. 

V,  p.  13. 

(44)  W.ASHBOURN.     Brit.  Med.  Jour..  Nov.  4,  1899. 

(45)  Wright.     Lancet,  Sept.  14,  1901,  p.  715. 

(46)  Jour.     Path,     and     Bact.,       1911.       Micrococcus 

gonorrhoea. 

(47)  Cent,  jiir  Bakt.,  Bd  58,  p.  259.  Bacillus  perfringeos. 


CHAPTER  III 


THE   AETIOLOGY   OF   DENTAL   CARIES 


CHEMISTRY 

As  dental  caries  is  the  result  of  a  chemico- 
parasitical  process  originating  outside,  and 
independent  of,  the  substance  of  tlie  tooth, 
it  is  necessary  to  have  a  kno^^ledge  of  the 
phenomena  associated  witli  this  process.  It 
may  be  said  at  once  that  the  process  is  essenti- 
ally one  of  fermentation,  and  all  the  conditions 
requisite  for  fermentation  to  take  place  should 
be  recognized.  It  is,  however,  hardly  necessary 
to  allude  to  certain  conditions  constantly  present 
in  the  mouth,  e.  g.  warmth,  moisture,  and  more 
or  less  free  exposure  to  air  and  bacteria  ;  and  as 
a  general  knowledge  of  fermentative  processes 
is  presumed  to  be  possessed  by  the  reader, 
oidy  those  variable  conditions  specially  con- 
cerned with  the  aetiology  of  dental  caries  will 
be  fully  referred  to. 

The  fermentative  changes  that  the  various 
food-stuffs  undergo  when  retained  in  the 
mouth  are  briefly  as  follo^^s — 

Proteid  (nitrogenous)  food-stuffs  undergo  de- 
composition resulting  in  a  large  number  of 
complex  products  whose  reaction  becomes 
alkaline. 

Fats  do  not  ajjpear  to  undergo  much  change, 
but  «liat  little  fermentation  takes  place  seems 
as  a  rule  to  result  in  an  alkaline  rather  than  an 
acid  reaction. 

Carbo-hydrates. — The  fermentation  of  this 
grouj)  of  food-stuffs  is  by  far  the  most  important 
from  the  point  of  view  of  the  aetiology  of  dental 
caries.  The  carbo-hydrate  food-stuffs  may  be 
considered  under  three  heads — 

(1)  Cellulose. — ThLs  is  a  peculiarly  inert 
substance,  and  probably  but  little  acted  upon 
by  the  bacteria  of  the  mouth.  Although 
chemically  inactive,  cellulose  is  important  from 
the  point  of  view  of  its  physical  characteristics, 
as  it  stimulates  thorough  mastication,  which 
is  detergent  in  its  effects. 

(2)  Starch. — Starch  undergoes  fermentation 
in  the  mouth,  relatively  rapidly  after  it  has 
been  boiled  or  cooked.  Firstly,  it  undergoes 
fermentation  into  dextrose,  maltose,  and  dex- 
trin, as  the  result  of  the  action  of  the  ptyalin 
of  the  saliva.  The  dextrose  and  maltose 
are  then  acted  on  by  bacteria ;  and  lactic 
acid,  together  with  traces  of  other  acids,  is 
produced. 


The    following   chemical    equations    indicate 
(without  detail)  the  changes  inidergone — 


C,,H,„0,-, 

M-  3H.,0 

=  3(C„H,A) 

Starch 

Grape-sugar 

(Dextrose) 

(Glucose) 

C„H,.p, 

= 

2{C.,;H.,P,) 

Grape-sugar 

Lactic  acid 

(3)  Sugar. — Sugar,  likev\Lse,  undergoes  fer- 
mentation in  the  mouth  resulting  in  the  forma- 
tion of  lactic  acid,  but  the  nature  of  the  change 
differs  with  the  different  kinds  of  sugars.  Cane- 
sugar  and  milk-sugar  undergo  a  hydrolytic 
fermentation,  being  converted  by  the  invertia 
of  the  bacteria  into  dextrose  and  laevulose, 
thus — 

C,.;EI.,P„  +  H,0  =  CgHi^Oe  +  C,^,X>, 
Cane  sugar  Dextrose      Laeviilose 

These   then    undergo    fermentation   into    lactic 
acid  as  previously  indicated. 

Grape-sugar,  dextrose,  laevulose,  and  glucose, 
as  stated,  undergo  direct  fermentation  into 
lactic  acid.  It  will  be  observed  that  the 
fermentation  of  the  grape-sugar  group  is  direct, 
and  that  of  the  cane-sugar  indirect ;  and  Stanley 
Colj'cr  has  suggested  that  the  directly  ferment- 
able sugars  are  more  destructive  to  the  teeth 
than  cane-sugar ;  but  according  to  Miller,  there 
seems  to  be  no  considerable  difference  of  time 
in  respect  to  the  beginning  of  fermentation 
in  the  two  groups,  and  the  one  is  apparently 
about  as  detrimental  to  the  teeth  as  the  other. 
Except  in  the  case  of  the  fermentation  of 
starch  into  dextrose  and  maltose,  the  decom- 
positions are  the  result  of  the  action  of  bacteria, 
and  the  products  are  not  exactly  simple ; 
traces  of  other  substances  are  produced  at  the 
same  time  wliich  do  not  seem  to  be  of  any  im- 
portance in  the  aetiology  of  caries.  There  is  one 
fermentation,  however,  that  should  be  noted, 
namely,  the  mannitic  or  viscous  fermenta- 
tion of  cane-sugar,  as  the  gummy  product 
prevents  the  normal  self-cleansing  processes. 
This  may  be  represented  by  the  folio  whig 
formula — 

25(C,„H2,0„)  -t-  25(H.,0)  = 
Cane-sugar 


12(C„H.,„0,„)  +  24(C,H„0,,)  +  12(C0,)  +  12(H,0) 
Girni  Mannite 


282 


283 


While  tlie  fermentation  of  carbo-hydrates  in 
immediate  contact  \(  ith  the  enamel  (occasion- 
ally with  the  dentine  or  cementum)  constitutes 
wliat  may  be  considered  the  ])rimary  stage  of 
dental  caries,  it  is  in  the  conditions  that  favour 
the  undue  loihjement  of  carbo-hyckates  and 
bacteria  that  the  aetiological  factors  must  be 
sought.  As  acid-forming  micro-organisms  are 
ubiquitous,  and  carbo-hydrates  practically 
always  constitute  part  of  a  meal,  it  is  neces.sary 
particularly  to  note  why  in  some  mouths  there 
should  be  undue  retention  of  carbo-hydrates 
and  micro-organisms  leading  necessarily  to 
fermentation,  and  why  in  other  mouths  carbo- 
hydrates should  not  lodge  undidy.  Attention 
must  therefore  be  directed  to  the  conditions 
that  favour — 

(1)  The  undue  retention  of  carbo-hydrates  in 
the  mouth,  or  more  especially  in  the  crevices 
of,  and  between,  the  teeth  ;  and 

(2)  The  proliferation  of  the  acid-forming 
micro-organisms. 

(1)  The  undue  retention  of  carbo-hydrates  m 
the  mouth  results  from  the  nature  of — 

(a)  The  food. 

(b)  The  form  and  arrangement  of  teeth. 

(c)  Arrested  or  insufficient  flow  of  the  saliva. 

(d)  The  dietetic  habits. 

(a)  The  most  important  factor  in  causing 
the  midue  retention  of  carbo-hydrates  in  the 
mouth  is  the  nature  of  the  food  itself.  In 
considering  this  subject  reference  to  the  albu- 
minous foods  will  for  simplicity  be  more  or 
less  omitted,  as  their  lodgement  is  not  of  the 
same  positive  importance  with  regard  to  the 
aetiology  of  dental  caries.  Certam  classes  of 
foods  are  now  recognized  as  being  peculiarly 
liable  to  lodge  in  the  crevices  of,  and  between, 
the  teeth.  In  general  it  may  be  said  that 
fibrous  and  acid  foods,  such  as  fresh  fruit  and 
vegetables,  do  not  tend  to  lodge,  except  when 
the  teeth  are  abnormal  in  their  arrangement ; 
and  even  when  such  foods  do  lodge  they  are 
practically  harmless  from  the  point  of  view 
of  dental  caries,  for  during  mastication  the 
sugary  and  starchy  matters  are  the  first  to 
be  expressed  from  the  bolus  and  swallowed, 
while  the  shreds  which  may  lodge  are  relatively 
free  from  fermentable  carbo-ln^diates.  On  the 
other  hand,  many  of  the  prepared  foods, 
especially  those  in  which  the  fibrillar  element 
has  been  destroyed  or  eliminated,  tend  to 
lodge  unduly  about  the  teeth ;  thu.s  biscuits, 
soft  or  doughy  bread,  and  almost  all  prepar- 
ations of  cereal  food,  are  liable  to  lodge  in 
the  crevices  of  the  teeth  (35).  The  firm  and 
fibrillar  nature  of  certain  foods  encourages 
mastication,  and  stinudates  the  natural  self- 
cleansing  of  the  mouth,  whereas  highly  refined 
and,  more  especially,  soft,  bland,  alkaline  foods 


— porridge,  milk  puddings,  potatoes  and  gravy, 
bread  soaked  in  milk,  etc. — are  liable  to  be  con- 
sumed without  that  amount  of  mastication  and 
insalivation  which  is  necessary  for  the  dislodge- 
mcnt  of  food  that  may  be  of  a  sticky  nature. 
Some  foods  are  not  sticky  in  themselves,  but  they 
may  become  sticky  in  the  mouth  ;  thus  sugar, 
in  addition  to  becoming  fermented  in  part  into 
lactic  acid,  also  undergoes  a  mamiitic  fermenta- 
tion, resulting  in  the  formation  of  a  gummy 
sub.stance,  which  is  liable  not  only  to  stick  about 
the  teeth,  but  also  to  retam  the  other  food 
particles  about  the  teeth.  Thus  a  combination 
of  starch  and  sugar,  as  found  in  cake  and  sweet 
biscuits,  is  likely  to  be  particularly  liable  to 
lodge  about  the  teeth.  Similarly,  combina- 
tions such  as  bread  and  marmalade,  or  jam, 
are  liable  to  lodge  about  the  crevices  of  the 
teeth  if  they  form  the  last  part  of  the  meal. 

Further  reference  will  be  made  to  the  relative 
lodgeability  of  foodstuffs  ;  enough  has  been  said 
to  indicate  how  the  nature  of  the  foods  may 
lead  to  the  undue  lodgement  of  carbo-hydrates, 
which  are  necessary  for  the  production  of  acid 
by  bacteria,  while  on  the  other  hand,  food  of 
a  detergent  nature  may  not  only  be  eaten  with- 
out leavmg  food  particles,  but  may  also  clean 
the  mouth  of  sticky  carbo-hydrates  and  bacteria, 
which  may  have  been  lodging  about  the  teeth 
before  the  fibrillar  foods  were  eaten. 
•  (h)  With  regard  to  the  form  and  arrange- 
ment of  the  teeth,  it  is  obvious  that  pits  or 
abnormally  deep  crevices  predispose  to  the  undue 
retention  of  food  particles.  The  abnormal 
relation  of  one  tooth  to  another  generally  may  be 
said  also  to  predispose  to  the  undue  lodgement 
of  food,  for  the  normal  inverted  V-shaped  space 
is  replaced  by  some  other  arrangement.  Tilted 
molar  or  premolar  teeth  are  peculiarly  liable  to 
give  rise  to  undue  lodgement  of  carbo-hydrates, 
because  the  normal  V-shaped  inter-space,  filled 
as  it  normally  is  with  the  gum,  is  the  most 
perfectly  adapted  for  least  lodging  and  easiest 
self-cleansing. 

Recession  of  the  Gums,  by  removing  the  inter- 
dental pad  of  gum,  favours  the  undue  retention 
of  carbo-hydrates  and  therefore  jsredisposes  to 
caries. 

Abnormal  Relation  of  the  teeth,  more  especially 
of  the  thu'd  molars,  to  the  surrounding  soft  parts 
or  to  the  opposing  teeth,  is  a  frequent  cause  of 
the  undue  retention  of  carbo-hydrates. 

(c)  More  or  less  complete  arrest  of  the  flow 
of  saliva  from  constitutional  causes  is  a  rare 
condition  except  during  fevers ;  when  it  is  pro- 
nounced or  prolonged,  caries  correspondingly 
tends  to  be  rapid  and  general. 

(d)  Dietetic  Habits  have  a  considerable  infiu- 
ence  over  the  lodgement  of  food  particles. 
Thus,  for  example,  the  taking  of  a  meal  immedi- 
ately before  going  to  bed,  or  the  eating  of  sweets 


284 


in  bed  before  going  to  sleep,  when  the  self- 
cleanhig  processes  are  in  abeyance,  tends  to 
give  rise  to  undue  lodgement  of  carbo-hydrates. 
Frec|uency  of  meals  may  also  be  mentioned,  not 
that  the  meals  need  necessarily  leave  carbo- 
hydrates ill  the  mouth,  but  if  the  meals  are  of 
such  a  character  as  to  leave  starch  or  sugar, 
each  successive  meal  renews  the  supply.  Still 
further  is  this  an  important  consideration  when 
sweets  are  eaten  more  or  less  continuously,  thus 
supplying  the  bacteria  \\ith  a  corresponding 
supply  of  food.  Other  habits  such  as  the  con- 
suming of  food  with  little  or  no  mastication,  or 
the  cb-inking  of  liquids  m  ith,  rather  than  after, 
meals  may  be  mentioned. 

(2)  The  Undue  Retention  of  Micro-Organ  isms 
about  the  Teeth. — The  proliferation  of  micro- 
organisms is  markedly  influenced  by  the  environ- 
ment in  which  they  exist,  and  this  is  jjarticularly 
true  of  the  micro-organisms  of  the  mouth. 
Notwitlistandmg  repeated  efforts,  it  has  been 
found  impossible  to  cultivate  certain  bacteria 
outside  tfie  mouth,  so  sensitive  are  they  to 
alterations  m  their  environment.  Although 
nearly  all  the  bacteria  found  in  the  mouth  may 
cause  acid  fermentation,  or  putrefactive  changes, 
according  to  the  medium  in  which  they  exist, 
they  may  for  convenience  in  elucidating  certam 
aetiological  details  all  be  mcluded  in  the 
following  divisions — 

(1)  Those  most  generally  active  in  the  pro- 
duction of  acid ;  and 

(2)  Those  most  generally  active  in  the  putre- 
factive processes. 

As  these  groups  of  micro-organisms  flourish 
best  in  the  media  that  permit  of  their  most 
active  development,  it  follows  that  the  acid 
producers  are  favoured  \\hen  carbo-hydrates 
(their  natural  food)  remain  in  the  mouth. 
When,  therefore,  carbo-hydrates  lodge  unduly 
about  the  teeth,  then  correspondingly,  acid 
fermentation  is  marked  and  caries  tends  to  be 
induced  ;  the  acid-forming  bacteria  are  specially 
favoured  and  proliferate  unduly,  thus  increasing 
the  rapidity  and  intensity  of  the  acid  fermenta- 
tion. E.  C.  Ku'k  suggested  that  the  type  of 
micro-organisms  was  modified  by  the  presence 
of  glycogen  in  the  saliva ;  but  it  would  appear 
that  glycogen  is  not  present  (19)  in  the  saliva 
as  it  issues  from  the  salivary  ducts,  and  except 
in  diabetics  such  cause  of  modification  of  the 
oral  flora  cannot  be  presumed. 

On  the  other  hand,  acid  foods  tend  to  prevent 
the  proliferation  of  the  acid-forming  bacteria, 
for  acids  and  alkalies,  especially  the  former, 
even  in  very  dilute  solution  retard  the  develop- 
ment of  bacteria.  So,  too,  the  growth  and  fer- 
ment activity  of  bacteria  are  always  more  or 
less  influenced  by  theu-  own  waste  products, 
and  the  bacteria  themselves  are  often  destroyed 


by  the  action  of  the  acid  that  they  have  pro- 
duced (20).  It  follows  that  the  acid-forming 
bacteria,  more  esjiecially,  are  retarded  in 
activity  by  the  acids  that  are  present  ui  so 
many  food-stuffs  (fruits  and  vegetables).  The 
effect  of  acid  may,  however,  be  counter- 
balanced by  the  presence  of  easily  fermentable 
carbo-hydrates ;  thus,  for  example,  grajies, 
which  are  acid  and  contaui  some  20  per  cent 
of  sugar,  seem  under  certain  circumstances,  as  in 
grape-cure  treatment,  to  induce  dental  caries. 
Agam,  a  diet  of  an  albuminous  nature  favours 
those  putrefactive  bacteria  whose  natural  habitat 
is  an  albuminous  medium.  It  may  be  said  that 
the  putrefactive  micro-organisms  are  normally 
ah^ays  favoured  in  a  clean  and  healthy  mouth, 
because  of  the  albuminous  nature  of  the  mucus, 
salivary  corpuscles,  proteid  bodies,  and  epi- 
thelial cells,  which  are  constantly  being  shed 
into  the  buccal  cavity.  Under  abnormal  cir- 
cumstances they  may  be  specially  favoured ; 
thus,  hi  case  of  gingivitis  and  pyorrhoea,  except 
when  recession  of  the  gum  has  given  rise  to 
places  particularly  favourable  to  the  retention 
of  food  particles.  In  this  is  found  an  explana- 
tion of  the  frequently  observed  fact  that  the 
Ul-cared-for  and  dirty  mouths  of  hospital 
patients  may  l)e  remarkably  free  from  dental 
caries. 

Another  pouit  should  be  noted.  To  have 
the  production  of  acid  kept  up  it  is  necessary 
to  renew  the  supply  of  carbo-hydrates  periodi- 
cally, otller^\■ise  putrid  decomposition  is  set  up 
and  alkalinity  results.  It  is  probably  on  this 
account  that  when  there  is  more  or  less  com- 
plete stagnation  in  the  crevices  of  the  teeth, 
e.  g.  when  there  is  no  opposing  tooth,  caries 
is  rarely  rapid. 

Independently  of  the  particular  kinds  of 
micro-organisms  that  are  favoured  by  lodguig 
food  particles,  there  is  an  important  general 
effect  produced  on  the  bacteria  of  the  mouth 
by  different  kinds  of  diet.  In  the  presence 
of  carbo-hydrates  acid  is  produced  even  when 
mixed  with  a  large  proportion  of  albuminous  food, 
while  in  the  presence  of  purely  albuminous  food 
the  resultmg  products  are  alkaline.  Food  that 
demands  vigorous  mastication  and  insalivation 
is  most  effective  in  dislodging  the  bacteria  that 
may  be  clinging  about  the  more  or  less  exposed 
parts  of  the  teeth,  while  the  bacteria  of  a  less 
adhesive  nature  are  effectually  washed  away ; 
and  it  would  appear  that  some  of  those  bacteria 
that  are  most  adhesive  are  of  the  putrefactive 
rather  than  of  the  acid-forming  kind  (11).  It 
thus  seems  j)robal)le  that  the  putrefactive 
bacteria  may  help  to  prevent  caries  by  forming 
a  coating,  which  tends  to  become  alkaline  over 
unrubbed  parts  of  the  enamel ;  although  at 
places  lodging  carbo-hydrates  frequently,  it 
would    be    unlikely    to    find    the    putrefactive 


285 


bacteria  only.  After  the  bacteria  are  effectu- 
ally dislodged  by  food  that  demands  vigorous 
mastication,  it  is  obvious  that  even  though  the 
carbo-hydrate  foods  lodge  after  a  meal,  the 
amount  of  fermentation  wUl  be  much  less  than 
when  soft  food  is  masticated  and  incorporated 
with  the  bacteria  without  dislodging  them. 

Although  the  type  of  bacteria  has  a  certain 
importance  from  an  aetiological  point  of  view, 
it  should  be  remembered  that  the  bacterial 
flora,  or  the  relative  predominance  of  any 
particular  type,  may  be  quickly  altered  by  the 
lodgement  of  different  kinds  of  foods.  As  a 
matter  of  experiment  it  is  found  that  the  saliva 
of  immunes,  a^  a  rule,  produces  less  acid  Ijy 
fermentation  in  a  given  time  (18)  than  average 
saliva,  yet  this  is  principally  in  the  first  t\^enty- 
four  hours.  Correspondingly,  too,  it  may  be 
said  that  tho.se  who  are  generallj'  called  immune 
are  those  who  as  a  rule  do  not  eat  such  tj^es 
of  meals  as  A\ould  induce  the  undue  proliferation 
of  acid-forming  bacteria. 

DIET  IN  INFANCY  AND  CHILDHOOD 

Diet  in  infancy  and  childliood  plays  an  im- 
portant part  in  the  aetiology  of  dental  caries  (37). 
Mother's  milk  is,  of  course,  the  best  possible 
diet  for  infants,  and  it  may  be  said  that  this 
ampl}',  perhaps  lavishly,  supplies  all  the  re- 
quirements of  all  the  organs  of  the  growing 
child ;  but  it  may  not  be  possible  for  tlie  child 
to  be  provided  with  mother's  milk,  and  the 
question  immediately  arises  whether  the 
artificial  substitutes  supply  these  requirements, 
and  more  especially  ^^hether  bottle-feeding 
supplies  the  developing  teeth  with  such  nourish- 
ment as  will  ensure  thek  perfect  development. 
When  due  precautions  as  to  sterilization  and 
general  cleanliness  are  taken,  it  is  said  that  the 
chUd  always  thrives  (6),  but  when  the  methods 
and  surroundings  are  unhygienic  various  dis- 
turbances may  take  place ;  if  then,  an  effect  is 
produced  on  the  developing  teeth  it  would 
appear  to  result  from  such  disturbances. 
Whether  again  these  dLsturbances  produce  an 
effect  on  the  developing  teeth  such  as  will, 
after  the  eruption  of  the  teeth,  predispose  to 
dental  caries  has  further  to  be  considered.  As 
has  just  been  said,  when  all  goes  well  the  general 
bodily  development  of  the  infant  does  not 
suffer;  nor  do  the  teeth  suffer  as  far  as  it  is 
known ;  that  is  to  say,  they  appear  on  eruption 
to  be  perfectly  normal.  There  is,  however,  a 
certain  projjortion  of  cases  both  in  bottle-fed 
and  breast-fed  children  in  which  the  teeth  are 
not  perfectly  formed,  but  emerge  through  the 
gums  pitted  or  grooved  (hypoplasia).  (See 
Chapter  III,  p.  47.)  It  nuiy  be  that  the  pro- 
portion of  hypo])lasic  teeth  Ls  greater  among 
the     bottle-fed    than     among    the    breast-fed, 


because  such  bottle-fed  children  are,  through 
neglect  of  necessary  precautions,  more  subject 
to  grave  constitutional  disurbances,  which 
may  be  presumed  to  affect  the  developing 
teeth,  and  Xorman  Bennett  attributes  the  com- 
monest type  of  hypoplasia  to  a  condition  of 
general  ill-health  and  digestive  derangement 
brought  on,  no  doubt,  in  many  ca.ses  by  errors 
in  feeding.  The  specific  fevers  that  would 
appear  to  give  rise  most  frequently  to  hypo- 
plasia are  measles  and  scarlet  fever,  but  it  is 
not  definitely  known  that  these  are  proportion- 
ately more  frequent  among  the  bottle-fed 
children  than  they  are  among  the  breast-fed. 
However,  while  recognizing  the  want  of  definite 
knowledge,  it  may  be  said  that  bottle-feeding 
may  somewhat  predispose  to  measles,  scarlet 
fever,  and  other  constitutional  diseases,  which 
maj^  be  presumed  to  affect  the  teeth  in  such  a 
way  as  to  gi\-e  rise  to  hypoplasia,  though  it  is 
impo.ssible  to  say  that  bottle-feeding  can  be 
considered  an  aetiological  factor  in  dental  caries 
of  any  importance,  especially  with  regard  to 
the  deciduous  teeth  (which  are  oidy  hyijoplasic 
in  one  or  two  per  cent  of  cases).  The  question 
of  bottle-feeding,  however,  as  an  aetiological 
factor  in  dental  caries,  has  been  studied  in 
another  way.  R.  B.  Hunter  examined  some 
5U0  .school-children's  teeth  and  concluded  as 
follows.  Of  the  children  who  were  breast-fed 
only,  the  teeth  were  "good"  in  4-1  per  cent, 
■"  moderate  "  in  35  per  cent,  "  poor  "  in  17  per 
cent,  and  "  bad  "  in  5  per  cent.  Among  the 
children  who  were  artificially  fed  only,  the 
teeth  were  "  good  "  in  33  per  cent,  "  moderate  " 
in  43  per  cent,  "  poor  "  in  16  per  cent,  and 
"  bad  "  in  8  per  cent.  From  this  it  will  be  ob- 
served that  the  comparison  does  not  lend  itself 
to  any  deduction  of  practical  importance ;  at 
least  it  does  not  appear  to  throw  much  light 
on  the  extraordinary  prevalence  of  dental 
caries  at  the  present  day. 

The  next  stage  to  be  considered  is  the  period 
of  transition  from  the  purely  milk  diet  to  the 
mixed  and  varied  diet  of  later  life.  This  takes 
place  concurrently  with  the  eruption  of  the  de- 
ciduous teeth  and  concomitant  changes  in  the 
alimentary  canal.  It  should  be  noted  that 
the  change  is  not  precisely  from  liquid  milk  to 
the  solid  and  varied  diet  of  adult  life,  but  from 
sucking  liquid  out  of  the  mother's  brea.st  to 
the  taking  of  solid  food  into  the  anterior  part  of 
the  mouth  and  subjecting  it  to  a  gnawing  and 
sucking  in  a  maimer  similar  to  the  sucking  of 
the  mother's  breast.  When  an  infant  is  tirst 
given  a  piece  of  solid  food,  say  a  piece  of  Ijread 
or  a  crust,  it  gnaws,  insalivates,  and  sucks 
it,  thereby  making  the  first  stage  in  the  tran- 
sition from  breast-feeding  to  solid  food.  Later, 
when  the  molar  teeth  come  into  position,  a 
further  change  is  brought  about,  for  the  infant 


286 


then  takes  the  sohd  food  uito  the  mouth  and 
throws  it  on  to  the  molar  teeth  to  be  more 
rapidly  disintegrated,  insalivated,  and  prepared 
for  swallo\\ing  in  a  more  or  less  liquid  state. 
As  the  teeth  give  a  definite  indication  of  the 
nature  of  the  food  for  which  the  infant  is  at 
any  particular  age  adapted,  it  is  obvious  that 
untU  the  incisors  erupt  milk  diet  alone  is  indi- 
cated. Similarly,  when  only  incisor  teeth  have 
erupted,  food  that  can  be  gnawed  and  sucked 
(in  addition  to  milk)  is  ^\'hat  may  be  regarded  as 
the  type  of  food  for  which  the  child  is  obviously 
adapted  at  that  age.  With  the  eruption  of 
the  deciduous  molar  teeth  a  proportionately 
greater  amount  of  solid  food  is  indicated. 
Divergence  from  these  uidications  as  to  diet 
is  not  conducive  to  the  best  results,  and  the 
specially  harmful  results  with  regard  to  caries 
may  be  briefly  alluded  to.  From  the  time  of 
the  eruption  of  the  incisor  teeth  to  the  eruption 
of  the  molar  teeth  the  diet  should  be  mother's 
milk  supplemented  by  an  increasing  amount 
of  solid  food  that  can  be  gna-\\ed  and  sucked, 
e.g.  crusts,  bread  rolls,  toast,  rusks  and  butter. 
If  such  food  is  not  given  in  a  form  in  which  it 
may  be  gnawed  and  sucked,  in  other  words 
if  it  is  soaked  in  milk,  the  incisor  teeth  are  not 
subjected  to  the  normal  cleansing  resulting 
from  the  gnawing  of  the  food,  and  carbo-hy- 
drates may  lodge  about  the  necks  of  the  teeth 
and  undergo  acid  fermentation,  while  from 
want  of  use  (assuming  that  the  child  is  not  per- 
mitted to  chew  other  things)  they  may  even 
become  relatively  tender.  But  the  incisor 
teeth  on  account  of  their  small  size  and  shape 
do  not  tend  to  lodge  food  much,  and  bread 
soaked  m  milk  is  not  likely  to  do  much  harm 
by  inducing  dental  caries  in  these  teeth  ;  never- 
theless even  at  this  stage  dental  caries  may  be 
initiated  near  the  gum  margins.  It  is  however 
when  the  molar  teeth  come  into  position  that 
the  harmful  results  of  a  diet  almost  exclusively 
of  a  "  short  "  or  soft  nature  is  most  obvious,  for 
the  crevices  of  the  molar  teeth  and  the  spaces 
between  them  are  liable  to  retain  carbo- 
hydrate foods ;  and  if  no  food  that  will 
stimulate  the  self -cleansing  processes  is  eaten, 
caries  is  almost  mevitable  m  these  situations. 
Thus,  therefore,  a  child's  diet  between  the 
twelfth  and  thirteenth  months  (exclusive  of 
the  milk)  should  not  be  restricted  to  porridge, 
bread  soaked  in  mOk,  milk  puddings,  potatoes 
and  gravy ;  much  less  should  the  child  be 
given,  in  addition  to  these,  sweet  cake  and 
sweets.  If  such  a  diet  is  adopted  caries  wiU 
gradually  make  its  appearance,  first  in  the 
crevices  most  liable  to  retam  the  carbo- 
hydrates, and  later  even  in  less  retentive 
places  such  as  the  necks  or  buccal  sides  of  the 
teeth.  In  addition  to  this,  when  young  children 
are  restricted  to  soft   foods  they   soon  tend  to 


avoid  foods  that  require  much  mastication,  e.g. 
crusts. 

After  all  the  deciduous  molars  have  come 
into  place  it  is  particularly  necessary  to  avoid 
restrictmg  chUdxen  to  a  dietetic  regime  that 
will  favour  the  onset  of  dental  caries  ;  and  as  by 
this  time  the  dental  armamentarium  is,  in  relation 
to  the  size  and  needs  of  the  child,  practically 
the  same  as  or  greater  than  in  adults,  so  corre- 
sponduigly  should  the  diet  approximate  in  type 
to  that  which  is  physiologically  correct  for  adults. 
Three  meals  a  day  are  from  the  point  of  view 
of  dental  caries,  as  probably  also  from  other 
points  of  view,  to  be  preferred  to  more  frequent 
meals,  for,  as  usually  happens  when  a  larger 
number  of  meals  are  taken,  they  are  to  a  certain 
extent  necessarily  restricted  to  kinds  of  food 
that  tend  to  digest  (and  ferment)  quickly  and  to 
lodge  about  the  teeth,  and  therefore  to  induce 
dental  caries.  Moreover,  with  more  than  three 
meals  daily  it  is  generally  found  necessary  with 
children  to  let  one  of  the  meals  be  taken  imme- 
diately before  going  to  bed ;  and  as  the  child 
naturally,  from  other  physiological  considerations, 
is  only  able  to  take  a  light  meal  at  this  time, 
it  is  usually  given  bread-and-milk  or  something 
else  of  a  fermentable  and  non-detergent  type. 
With  regard  to  meals  in  general,  it  may  be  said 
that  from  the  age  of  two  years  onwards 
they  should  always  contain,  firstly,  a  sufficiency 
of  food  that  will  stimulate  thorough  mastication 
sufficiently  well  to  dislodge,  as  efi'ectually  as 
possible,  bacteria  that  may  be  clinguig  about 
the  teeth  and  mucous  membrane  of  the  mouth ; 
for  m  so  far  as  this  is  not  done  the  fermentation 
of  the  carbo-hydrates  that  may  lodge  after 
the  meal  wiU  be  proportionately  intense  and 
rapid.  Secondly,  the  meals  should  not  end 
with  food  of  a  sticky  or  pasty  nature,  for  other- 
wise the  bacteria  will  be  supplied  with  all  that 
is  requisite  for  their  rapid  development  and, 
consequently,  for  the  initiation  of  dental  caries. 
In  order  to  put  these  principles  into  a  clear 
light,  the  type  of  diet  that  tends  to  induce 
dental  caries  may  be  outlmed. 

Diet  Table. — Breakfast. — Porridge  and  mUk, 
bread  and  marmalade.  Then  a  supplementary 
breakfast,  a  few-  hours  later,  of  a  glass  of  mUk 
and  a  sweet  biscuit.  Dinner. — Mashed  potatoes 
and  gravy,  mUk  and  mUk-pudding,  jam-roll 
or  preserved  fruit.  Supper. — Bread  soaked  in 
mUk,  or  bread -and-jam,  cocoa,  and  cake,  and 
perhaps  a  supplementary  supper,  on  going  to 
bed,  of  a  glass  of  mUk  and  a  biscuit. 

It  should  also  be  remembered  that  the  taking 
of  soft,  sweet,  sticky  foods,  such  as  malted 
foods,  medicated  syrups,  etc.,  tends  to  induce 
dental  caries,  more  especially  when  they  are 
taken  three  times  a  day  after  meals. 

To  illustrate  and  impress  upon  those  who  may 
have  to  do  with  children  the  danger  of  sticky 


287 


carbo-hydrates  taken  at  the  end  of  meals,  they 
may  be  advised  to  kiok  into  the  mouth  of  a  cliild 
a  few  minutes  after  it  has  eaten,  say.  biscuits, 
sweet  cake,  or  cliocoh\te,  and  they  will  observe 
a  visible  amount  in  the  crevices  of  the  molar 
tcetl).  If  then  they  give  the  child  a  piece  of 
an  apple  to  eat  and  then  look  into  the  mouth, 
they  will  find  that  the  crevices  are  clean  and 
no  particles  of  the  food  are  to  be  seen.  An 
apple  not  only  stimnlates  mastication,  and  thus 
the  mechanical  and  hydro-dynamical  self- 
cleaning  processes,  but  on  account  of  its  acid 
and  aromatic  flavours,  it  also  stimulates  the 
chemico-physiological  self  -  cleanuig  processes 
most  effectually.  In  order  to  be  able  to  direct 
the  attention  of  parents  to  the  particular 
dietetic  errors  that  are  responsible  for  caries 
in  any  given  child,  it  will  be  found  useful  to 
ask  first  with  regard  to  the  physical  con- 
sistency of  the  food  :  Does  the  child  not  eat 
much  crisp  toast  ?  Does  it  try  to  avoid  eating 
crusts  ?  Does  it  not  eat  meat,  or  vegetables, 
or  fresh  fruit  ?  Then  ask  how  each  meal 
is  terminated  :  Does  it  finish  breakfast  with 
bread-and-marmalade  ?  Does  it  finLsh  dinner 
with  milk-puddings  or  jam-rolls  ?  Does  it 
finish  its  ne.xt  meal  with  cake,  bread-and-jam, 
or  bread-and-milk  ?  If  not,  with  what  foods 
or  li(iuids  does  it  terminate  its  meals  ?  Lastly, 
ask  iJE  the  child  eats  sweets  or  biscuits  between 
meals  or  before  going  to  bed  ?  The  parents 
may  direct  your  attention  to  the  fact  that  the 
child's  teeth  are  brushed  before  going  to  bed  ; 
this  may  in  general  tend  to  prevent  caries,  but 
when  caries  exists  it  cannot  have  been  effectual 
— it  .seldom  is  in  children,  and  does  not  appre- 
ciably simplify  the  problem  as  to  what  dietetic 
errors  have  to  be  corrected. 

CIVILIZATION 

It  is  a  well-recognized  fact  that  caries  is  most 
prevalent  among  the  civilized  races,  and  accord- 
ingly civilization  is  generally  mentioned  as  an 
aetiological  factor.  Various  explanations  of 
how  civilization  induces  caries  have  been  ad- 
vanced, and  may  be  briefly  reviewed. 

It  has  been  contended  that  the  soft  nature  of 
the  food  of  the  civUized  races  gives  rise  to  deterio- 
ration or  degeneration  of  the  teeth.  Two  ex- 
planations of  tliLs  have  been  made.  One  is 
that  the  pressure  brought  to  bear  on  the  teeth 
during  vigorous  mastication  increases  the  circula- 
tion of  the  blood  in  the  pulp  and  induces  increased 
deposit  of  lime-salts  or  more  perfect  calcifi- 
cation. Another  is  that  the  comparative  disu.se 
of  the  teeth  among  the  civilized  gives  rise  to 
degeneratioti  of  structure  according  to  the 
Lamarckian  hypothesis  of  heredity.  It  may 
be  said  however,  that,  if  either  of  the.se  two 
explanations    is    correct    they    cainiot    account 


for  the  prevalence  of  caries  in  the  deciduous 
teeth,  which,  among  savage  tribes  as  among 
the  civilized,  have  the  enamel  completely  calci- 
fied before  solid  food  is  eaten  at  all ;  nor  can 
they  account  for  any  supposed  degeneration 
of  the  enamel,  which  is  formed  before  it  becomes 
functionally  active. 

Another  theory  of  the  degeneracy  of  teeth 
resulting  from  the  influence  of  civilization, 
which  is  also  widely  accepted,  may  be  mentioned. 
It  is  contended  that  on  account  of  humane 
sentiments  among  the  civilized,  those  who  would 
naturally  in  savage  comnumities  be  extermi- 
nated before  maturity,  are,  among  the  civilized, 
rendered  fit  by  artificial  aid  to  marry  and  pro- 
pagate their  kmd.  It  is  pointed  out  that  among 
the  savages  the  tough  nature  of  their  food 
renders  it  almost  imperative  to  have  an  efficient 
masticatory  apparatus,  while  among  the  civil- 
ized not  only  are  the  foods  softened  and,  as  it 
were,  presented  in  a  semi-masticated  condition, 
but  also  the  patients  themselves  may  have  their 
teeth  restored  by  fillings,  crowns,  bridges,  etc. 
Difference  of  opinion  exists  with  regard  to  this 
explanation.  Those  opposed  to  it  contend  that, 
dental  caries  being  comparatively  rare  among 
the  uncivilized  (as  among  animals),  there  can 
be  but  little  elimination  on  this  account  (25) ; 
whOe  on  the  other  hand  they  contend  that  the 
unhygienic  conditions  of  the  mouth  a.s.sociated 
with,  and  resulting  from,  the  state  of  the  mouth 
when  the  teeth  are  more  or  less  ravaged  by 
dental  caries,  frequently  lead  to  premature 
death  among  the  civilized. 

The  last,  and  no  doubt  the  most  tenable, 
theory  to  which  reference  may  be  made  does  not 
recognize  that  there  is  any  degeneracy  of  the 
teeth.  On  the  contrary  it  is  contended  that 
the  foods  of  the  civilized  provide  an  ample  and 
adequate  supply  of  nourishment  for  the  develop- 
uig  teeth,  but  that  unfortunately  they  are  pre- 
sented in  a  form  that  renders  them  liable  to  lodge 
unduly  and  undergo  acid  fermentation  in  the 
mouth.  The  fine  milling  of  flour,  the  sugar 
refining,  etc.,  together  with  the  preparation  by 
cooking  of  foods  already  highly  refined,  tend  to 
decrease  the  foods  of  a  detergent  nature  and 
hicrease  those  that  tend  to  lodge  about  the  teeth. 
In  addition,  there  is  a  gratuitous  advocacy  of 
types  of  food  that  result  in  producuig  an 
unhygienic  state  of  the  mouth.  This,  however, 
will  no  doubt  soon  be  rectified  throughout 
civilized  nations  when  the  hygiene  of  the  mouth 
and  the  .science  of  dietetics  m  relation  to  dental 
hygiene  are  more  thoroughly  appreciated  and 
studied   by  the  medical  profession. 

Reference  may  here  be  made  to  the  well- 
known  fact  that  caries  is  a.ssociated  w  ith  certain 
occupations.  .Millers  and  bakers  (who  are 
habitually  hi-cathing  flour  dust),  sugar  refiners 
and  confectioners,   are   particularly  subject  to 


288 


caries.  How  this  results  is  so  obvious  to  those 
who  have  become  acquainted  with  tlie  pathology 
of  the  disease  and  conditions  favourable  to  the 
activity  of  the  exciting  cause,  that  it  has  been 
recognized  as  superfluous  to  assume  the  exist- 
ence of  susceptibility  to  dental  caries  among 
those  who  follow  these  occupations. 

RACE 

Several  investigations  have  been  made  with 
regard  to  caries  among  the  various  races  of 
mankind.  The  most  important  of  these  was 
that  undertaken  by  the  late  J.  R.  Mummery. 
Although  he  came  to  the  conclusion  that  general 
hygienic  conditions  are  often  as  much  concerned 
in  the  growth  of  healthy  teeth  as  food,  hLs 
investigation  has  supplied  us  with  facts  of  con- 
siderable importance  in  the  elucidation  of  the 
problem  of  the  aetiology  of  dental  caries.  Mum- 
mery's investigations,  together  with  others, 
show  that  no  race  is  exempt  from  dental  caries, 
and  further  that  the  degree  to  which  the  various 
races  are  afflicted  does  not  correspond  in  any 
way  with  the  natural  racial  divisions  as  recog- 
nized by  anthropologists,  except  in  so  far  as 
racial  divisions  are  associated  with  civilization. 
WHien,  however,  races  are  classified  according 
to  certain  dietetic  customs  a  general  conclusion 
is  arrived  at,  namely,  that  meat-eating  races 
are  less  frequently  affected  by  dental  caries 
than  mixed  feeders.  This  is  a  generalization 
subject  to  exceptions ;  thus,  among  modern 
savage  races  South  Americans  (aboriginal)  are 
principally  meat  eaters,  yet  show  27  per  cent 
of  caries,  while  some  mixed  feeders,  e.g.  East 
Indians  (North),  show  only  5-92  jjer  cent;  still, 
on  the  whole  the  truth  of  the  generalization 
is  well  established.  Similarly,  it  may  be  ob- 
served that  races  subsistmg  on  uncooked  foods 
are  more  or  less  exempt  from  caries ;  thus  the 
Pygmies  of  Central  Africa  are  free  from  the 
disease. 

It  should  be  noted,  however,  that  the  same 
race  may  have  within  itself  groups  that  show 
remarkable  differences.  Thus,  those  Kaffirs 
who  have  been  supplied  with  civilized  foods 
have  in  one  generation  become  totally  different 
(9)  with  regard  to  caries  from  those  who  are 
still  not  subjected  to  similar  dietetic  customs. 
Similarly,  the  aristocracy  of  ancient  Egypt  were 
much  affected  with  dental  caries,  while  those 
not  belongmg  to  that  class  were  comparatively 
free  from  the  disease  (30). 

Thus,  although  it  has  been  generally  assumed 
that  the  different  extent  to  which  the  various 
races  of  mankind  suffered  indicated  a  corre- 
sponding susceptibility  or  immunity  to  the 
disease  resultmg  from  hereditary  or  con- 
stitutional differences,  yet  an  analysis  of  the 
facts  revealed  in  the  light  of  our  present  know- 


ledge of  the  aetiology  of  the  disease  shows  that 
what  was  attributed  to  susceptibility  and  im- 
munity may  now  more  properly  be  regarded  as 
resulting  from  different  dietetic  habits  ;  for  those 
races  that  are  more  or  less  exempt  from  the 
disease  are  seen  to  live  chiefly  on  food  of  a 
kind  (meat,  uncooked  roots,  and  fruits)  that 
is  detergent  in  its  effects,  and  moreover  does 
not  readily  encourage  the  development  of 
acid-forming  micro-organisms,  nor  undergo  rapid 
acid  fermentation  in  the  mouth. 

Heredity. — The  dental  profession  has  long 
been  acquainted  with  the  fact  that  the  children 
of  parents  with  carious  teeth  are  more  liable 
to  have  carious  teeth  than  the  children  of 
parents  with  teeth  free  from  caries.  This  fact 
was  so  well  recognized  that  the  hereditary 
nature  of  the  disease  came  to  be  considered  as 
settled  beyond  question.  The  knowledge  of  the 
pathology  of  the  disease  precluded  the  possi- 
bility of  maintainmg  its  direct  inlieritance,  so 
that  it  came  to  be  believed  that  it  was  the 
hereditary  ■predisposition  that  accounted  for 
the  apparently  hereditary  nature  of  the  disease. 
Two  theories  to  account  for  tliis  predisposition 
were  advanced  :  the  first  that  it  resulted  from 
certain  hereditary  structural  deficiencies  of  the 
teeth,  the  second  that  it  resulted  from  hereditary 
peculiarities  of  the  oral  secretions.  When  the 
hereditary  nature  of  the  disease  was  assumed 
as  a  fact  it  was  of  course  necessary  to  account 
for  it  by  one  or  other  of  these  suppositions,  but 
which  of  them  should  be  considered  correct  was 
the  subject  of  much  controversy.  The  most 
thorough  investigations  seemed  rather  to  nega- 
tive both  views,  yet  the  conviction  remamed 
that  the  jDredisposition  to  caries,  whether  in- 
duced by  structural  deficiency  or  perverted 
secretion,  was  strongly  inherited.  It  is  a  well- 
known  fact  that  living  organisms  are  able  to 
produce  their  like,  and  that  the  resemblance 
between  a  child  and  its  parents,  though  never 
perfect,  may  nevertheless  extend  to  the  most 
minute  details  of  construction  and  function 
(40) ;  this  seemed  to  indicate  how  the  markedly 
hereditary  nature  of  the  disease  could  be  ac- 
counted foi',  although  the  nature  of  the  structural 
or  functional  variation  might  not  have  been 
discovered.  At  the  present,  however,  no  know- 
ledge exists  of  inherited  functional  variations 
that  might  predispose  to  dental  caries,  though 
assiduous  search  has  been  made  for  them ;  but 
certain  hereditary  structural  variations  that 
predispose  to  the  disease  are  recognized.  It 
is  obvious  that  variations  in  the  sizes  of  the 
teeth,  and  more  especially  the  depth  of  the 
crevices,  predispose  to  dental  caries  by  favouring 
the  undue  retention  of  food  particles  and 
micro-organisms  (in  conditions  favourable  to 
fermentation).  Simihirly,  pits,  when  resulting 
from   hereditary  causes  and  not  the  result  of 


289 


ill-health,  may  be  considered  as  hereditarily 
predisposing  to  dental  caries.  And  although 
it  may  have  to  do  rather  with  the  rapidity  of 
the  progress  of  the  disease  tlian  witli  its  cause, 
mention  may  liere  be  made  tliat  tliere  is  no  reason 
for  doubting  hereditary  variation  in  the  chemical 
or  molecular  constitution  of  tlie  teeth.  All  these 
variations  within  normal  limits  have,  however, 
peculiarly  little  to  do  with  tlie  prevalence  of 
the  disease  in  some  mouths  and  not  in  others, 
for  it  is  found  that  those  wlio  are  free  from  the 
disease  have  likewise  similar  variations  in  the 
depth  of  the  crevices,  etc. 

Many  observers  now  believe  that  the  here- 
ditary nature  of  the  disease  is  rather  apparent 
than  real,  and  that  what  had  been  taken  to 
indicate  inheritance  may  better  be  explained 
by  similarity  of  environment  (7) ;  or,  more 
explicitly,  that  the  dietetic  habits  of  parents 
and  children  being  similar,  the  results  as  regards 
caries  are  also  similar.  Moreover,  certain  facts 
with  regard  to  the  pathology  of  the  disease  make 
it  impossible  to  believe  that  there  is  an\'thing 
hereditary  beyond  the  predisposition  that 
various  conditions  might  produce  for  the  undue 
retention  of  food  particles.  Dental  caries  has 
been  shown  to  be  essentially  a  mutilation  in  its 
initial  stages,  and  therefore  the  belief  that  its 
increasing  prevalence  had  anjiihing  to  do  with 
the  fact  of  the  ancestry  having  been  the  subjects 
of  the  disease,  cannot  be  accepted.  Nor  could 
it  be  maintained,  even  by  those  who  believed  in 
the  inheritance  of  acquired  characters,  that  the 
soft  nature  of  civilized  food  tended  after  .several 
gcTierations  to  produce  a  sort  of  enamel  but 
feebly  resLstant  to  caries,  for  the  enamel  is 
passive  in  its  function. 

Tho.se  who  maintain  that  the  apparently 
hereditary  nature  of  the  disease  may  best  be 
explained  by  similarity  of  environment — dietetic 
habits — believe  that  the  nature  of  the  food  in 
relation  to  whether  it  leaves  the  mouth  in  a 
hygienic  state  at  the  end  of  a  meal,  or  other- 
wise, is  by  far  the  most  important  factor  in  the 
causation  of  the  disease.  Those,  on  the  other 
hand,  who  consider  that  the  differences  in  dietetic 
customs  cannot  account  for  the  facts,  believe 
that  ultimately  the  causes  of  susceptibility  and 
immunity  will  be  found  in  something  that 
may  be  discovered  in  relation  either  to  the  tooth 
substance  itself,  or  to  the  oral  secretions. 
They  further  consider  that  variations  in  sus- 
ceptibility at  different  periods  during  a  life- 
time are  to  be  explained  by  differences  in  the 
constitutional  states,  while  those  who  practically 
deny  the  hereditary  nature  of  the  disease 
attribute  such  apparent  su.sceptibility  almost 
entirely  to  hitherto  unsuspected  changes  in 
dietetic  habits  that  are  of  importance  from 
the  point  of  view  of  caries.  Thus,  for  example, 
the  fact  that  children  are  much  more  subject  to 
10 


caries  than  adults,  whose  teeth  from  irregu- 
larities and  other  causes  are  more  predisposed 
to  the  undue  retention  of  carbo-hydrates,  is 
attributed  to  the  custom  by  which  children  as  a 
rule  are  fed  on  the  softer  and  more  fermentable 
foods,  f .  (J.  bread  soaked  in  milk,  milk-puddiags, 
sweets,  potatoes  and  gravy. 

Before  the  role  played  by  the  physical 
characters  of  the  food  and  the  arrangement  of 
the  meals  was  ajjpreciated,  naturally  the 
differences  that  tended  to  bring  on  or  stave 
off  caries  were  unobserved,  and  a  belief  in  some 
um-ecognized  susceptibility  and  immunity  was 
required  to  account  for  the  prevalence  of  caries 
in  some  mouths  and  its  absence  in  others. 

THE  CHEMICAL  CONSTITUTION  OF  THE 
TEETH 

That  the  incidence  of  dental  caries  depended 
more  or  less  completely  on  the  perfection  of 
the  calcification  of  the  teeth  was  the  all  but 
universal  belief  of  the  dental  profession    until 
the  results  of  G.  V.  Black's  investigations  into 
the    chemical   and   physical    properties    of   the 
teeth  were  published  in  1895.     The  revelations 
that    he   made   with    regard    to    the   chemical 
constitution   of   the   teeth   have   received   sub- 
stantial  and  authoritative  corroboration ;   and 
though  the  correctness  of  his  findings  from  a 
chemical    point    of    view    is    now    universally 
admitted,    yet    certain    objections    have    been 
made,  not  only  to  his  inferences,  but  also  with 
regard  to  the  qualitative,  rather  than  the  quan- 
titative, chemical  composition  of  the  teeth.     The 
questions    involved    are    of    great    importance. 
For  very  good  reasons  set  forth  in  the  original 
papers.  Black  selected  sections  of  the  neck  of 
the  teeth  as  the  part  most  suitable  for  analysis, 
and  with  regard  to  this  part  he  set  forth  in 
detail  the  specific  gravity,  the  percentages  of 
water,  of  lime-salts,  and  of  organic  matter.     He 
contrasted  sections  of  teeth  that  had  been  taken 
from   carious,  and  those   that   had   been  taken 
from  sound,  teeth,  but  found  no  such  difference 
as  had  been  supposed  to  exist.     He  summarized 
his  results  with  regard  to  the  point  in  the  follow- 
ing «ords  :      The  teeth    of    persons    wJw  suffer 
much  from  caries  are  just  a.s  hard,  just  a-s  heavy, 
and  contain  just  as  much  lime-salts,  as  the  teeth 
of  persons  wJw  do  not  suffer  speciall;/  from  caries. 
The  objection  that  the  part  of  the  tooth  specially 
analysed  by  Black    is    not    the  part  that  is  of 
vital  importance  with  regard  to  the  aetiology  of 
dental  caries,  may  be  referred  to.     It  is  true 
that  the  enamel  is  by  far  the  most  important 
from  this  point  of  view.     At  the  same  time  it 
seemed  reasonable   to   infer  that    the   neck  of 
the   tooth   is   in  general  representative  of  the 
state  of  calcification  at  other  parts,  and  as  far 
as    the    dentine    is    concerned    this    has    been 


290 


experimentally  substantiated  by  Charles  Tomes.  1 
Chemical  analysis  of  the  enamel  is  apparently  ! 
extremely  difficult,  and  discrepancies  in  the 
published  results  of  such  analyses  seem  to 
indicate  this  difficulty,  rather  than  real  differ- 
ences m  the  chemical  constitution  of  the  enamel 
itself.  As,  however,  the  enamel  of  man,  horse, 
and  elephant,  shows  no  difference  (32)  with 
regard  to  the  amount  of  organic  matter  and 
water  accompanyuig  the  lime-salts,  it  is  probable 
that  little  difference  exists  between  different 
specimens  of  enamel  from  the  teeth  of  animals 
of  the  same  species.  The  difficulty  in  the 
chemical  analysis  of  the  enamel  being  recognized, 
it  seems  more  satisfactory  that  Black's  experi- 
ments on  the  enamel  were  also  directed  towards 
the  amount  of  crushing  strain  that  the  enamel 
would  bear,  for  in  this  way  his  results  are  a  more 
effective  reply  to  those  who  object  to  his  con- 
clusions on  account  of  his  not  taking  into  con- 
sideration the  molecular  constitution  of  the 
tooth.  His  exjjeriments  seem  to  show  that  no 
relation  whatever  exists  between  the  crushing 
strain  and  the  tendency  of  the  teeth  to  caries. 
Sunilarly,  it  may  be  presumed  that  the  teeth  of 
the  present  day  are  no  more  susceptible  to 
caries  as  a  result  of  their  mmute  constitution, 
for  "  the  ffiiest  lenses  reveal  not  the  slightest 
difference  between  enamel  ground  moist  from 
a  living  tooth,  and  tliat  which  has  lain  in  the 
earth  for  a  hundred  centuries"  (41). 

One  of  Black's  findings,  \\'hich  was  considered 
specially  surprising  by  those  who  believed  in 
susceptibility  and  immunity  existing  in  the 
tooth  substance,  ^^•as  the  fact  that  the  incisor 
and  canine  teeth  are  less  highly  calcified  than 
the  molar  teeth.  Tomes  gives  the  percentage 
of  lime-salts  for  the  incisors  as  11-5,  and  for  the 
molars  73'2.  These  results  are  practically 
the  same  as  those  recorded  by  Black,  and  more 
recently  by  Gasmann. 

Associated  with  the  belief  that  a  deficiency 
in  lime-salts  is  resjionsible  for  the  prevalence 
of  caries  there  were  certam  explanations  of 
how  this  came  about.  Thus  it  was  generally 
believed  that  deficient  calcification  was  associ- 
ated with  a  lack  of  the  mineral  constituents  in 
the  food  or  in  the  ^\ater.  It  was  also  assumed 
that  white  bread,  from  wliicli  all  the  bran  con- 
taining a  large  amount  of  jjhosphates  ^\•as 
removed,  was  responsible  for  defective  calcifica- 
tions ;  but  it  has  been  shown  that  less  phosphates 
were  assimilated  from  the  \\  hole-meal  bread  than 
from  the  white  bread  (16),  so  that  this  explana- 
tion could  not  have  been  maintained  even 
though  defective  calcification  of  the  teeth 
had  been  associated  \\ith  caries.  It  «"ould 
indeed  appear  from  experiments  carried  out 
on  rats  l)y  Chalmers  Watson  that  an  exclusively 
meat  diet^ — that  is,  one  very  deficient  in  lime-salts 
— although   affecting   the   development   of  the 


bones  (rickets),  had  no  apparent  effect  on  the 
development  of  the  teeth.  Deficiency  of  lime- 
salts  in  the  drinking  water  has  been  advanced 
as  a  cause  of  deficiency  of  the  mmeral  con- 
stituents of  the  teeth.  Rose  supports  this  view 
and  has  brought  forward  a  great  number  of 
figures  to  sho\\-  that  in  districts  having  a  large 
proportion  of  lime-salts  in  the  water  the  teeth 
of  the  inhabitants  showed  less  caries  than  in 
those  localities  where  the  drinkmg  water  was 
poor  in  lime-salts.  It  has,  however,  been 
pointed  out  that  in  certain  districts  (Gothland) 
where  the  water  does  contain  a  large  amount  of 
mmeral  matter  caries  is  very  prevalent,  while 
in  certain  other  districts  (Delarne,  Sweden) 
where  the  water  was  relatively  free  from  lime- 
salts  the  teeth  are  relatively  free  from  caries. 
Rose,  on  havmg  his  attention  called  to  this, 
explained  the  prevalence  of  caries  among  the 
Gothlanders  by  pointing  out  that  they  lived 
on  black  bread,  which  was  soft  and  sour  and 
moreover  contained  sugar ;  but  it  is  not  clear 
that  the  dietetic  customs  in  this  respect  are 
essentially  different  in  those  districts  m  Germany 
in  which  the  teeth  are  most  carious. 

It  is  just  possible  that  deficiency  of  lime-salts 
in  the  water  miglit  favour  the  progress  of  dental 
caries,  masmucli  as  it  might  be  presumed  that 
the  lime-salts  m  the  water  and  in  the  foods 
would  neutralize  or  modify  the  effect  of  acid 
formed  from  the  fermentation  of  carbo-hydrates. 
It  is  possible  also  that  when  lime-salts  are 
abundant  m  any  district  the  inhabitants  might 
instinctively  tend  to  eat  more  food  containing 
a  deficiency  of  lime-salts,  e.  g.  meat ;  and  vice 
versa.  Whether  either  of  these  possibilities 
throws  any  light  on  Rose's  statistics  or  not,  it 
is  difficult,  as  Tomes  and  Nowell  observe,  to 
reconcile  them  \\ith  the  chemical  analyses  of 
the  teeth  already  referred  to.  In  this  connec- 
tion it  may  be  mentioned  that  the  Esquimaux 
have  particularly  excellent  teeth,  though  they 
live  largely  on  meat  and  fat — that  is,  food  very 
deficient    in    lime-salts, — and    are    practically 

I  debarred  from  aU  the  kinds  of  foods — e.  g. 
cheese,  peas,  vegetables,  cow's  milk,  etc. — 
that  Rose  recommends  on  account  of  their 
richness  in  lime-salts,  while  they  drink  water 
(melted  snow)  that  is  about  as  free  from  lime- 
salts  as  though  it  had  been  distilled.  A  more 
plausible  theory  of  defective  development  of 
teeth  is  that  which  blames  a  disease — rickets — 
for  the  defects.  Some  have  held  this  view, 
but  while  they  have  cited  the  effect  of  rickets  on 
developmg  bone  as  justifymg  this  assumption, 
they  have  not  brought  forward  statistical 
evidence  such  as  could  be  considered  sufficient 
to  establish  the  claim.     StUl,  although  it  cannot 

]  be  said  that  rickets  has  been  proved  to  interfere 
with  the  development  of  the  enamel,  as  do  tiie 

[  e.xanthemata,  which   have  a  specific   effect   on 


291 


epithelium,  yet  inasmuch  as  rickets  is  a  disease 
acting  during  the  formation  of  tlie  teeth,  the 
possibility  of  such  effect  cannot  be  excluded. 
iShould  rickets  be  shown  to  be  a  cause  of  hypo- 
plasia of  the  enamel,  then  of  course  it  would 
predispose  to  caries,  inasmuch  as  pits  and  grooves 
tend  to  favour  the  undue  lodgement  of  food 
particles.  At  the  present  time,  however,  several 
authors  (2,  p.  51)  claim  that  defective  enamel 
formation  is  not  specially  associated  with  rickets 
(24),  while  others  (33,  p.  229)  are  of  the  contrary 
opinion. 

Although  the  chemical  composition  of  the 
tooth  does  not  appear  to  have  the  effect  in  pre- 
disposing to  caries  that  was  previously  assumed, 
yet  the  form  of  the  tooth,  more  especially 
pits,  crevices,  and  rough  enamel  surfaces, 
obviously  predisposes  it  to  caries  by  promoting 
the  undue  lodgement  of  carbo-hychates  and 
bacteria.  It  is  equally  obvious  that,  the  enamel 
being  absolutely  passive,  it  can  have  no  in- 
fluence ^^hatever  on  the  active  fermentative 
process,  nor  can  any  enamel  resist  decalcifica- 
tion provided  such  fermentation  is  sufficiently 
intense  and  prolonged.  Certain  defects  in  the 
enamel,  however,  influence  the  rate  and  progress 
of  the  decalcification.  Thus  a  crack  or  bruise 
of  the  enamel  (22)  vnder  a  focns  of  fermentation 
allows  of  the  easy  ingress  of  the  acid,  and 
consequently  leads  more  rapidlj-  to  its  decalci- 
fication. The  enamel  cuticle,  too,  offers  a 
certain  resistance  to  the  ingress  of  acid  (22), 
so  that  when  this  is  removed  or  abraded  the 
decalcification  is  made  more  easy.  8o  again, 
w  hen  the  outer  crust  of  the  enamel  is  worn  off, 
it  would  appear  from  experiments  made  by 
Stanley  Mummery  that  the  action  of  acid  is 
more  rapid  than  when  the  enamel  has  not  been 
subjected  to  abrasion.  This  is  of  interest, 
because  it  is  frequently  assumed  that  the  crevices 
of  the  teeth  offer  least  resistance  to  the  action 
of  acid,  on  the  assumption  that  there  is  generally 
defective  formation  of  the  enamel  between  the 
cusps  ;  however,  it  appears  that  the  worn  cusps 
of  the  enamel  are  least  resistant  to  acid.  This 
should  be  remembered,  because  a  generalized 
presence  of  carbo-hydrates  and  bacteria  in 
the  saliva,  together  with  points  of  least  resist- 
ance in  the  teeth  to  the  action  of  the  acid  formed, 
has  often  been  assumed  to  determhie  the 
incidence  of  caries.  In  view  of  what  has  just 
been  said  this  idea  cannot  be  maintained. 

SALIVA   AND  MUCUS 

The  influence  of  the  saliva  in  relation  to  the 
causation  of  dental  caries  has  been  the  subject 
of  much  research,  but  the  conclusions  of  the 
different  investigators  have  not  alwaj's  been  the 
same.  As,  however,  those  of  AliUer  are  both 
most  thorough  and  authoritative,  an  abstract 


of  them  may  be  given,  together  with  the  con- 
clusions of  some  other  investigators,  which  are 
not  in  harmonj''  witli  his. 

Miller  makes  the  following  summary — 

1.  Mixed  human  saliva  does  not  possess  the 
power  to  prevent  or  retard  processes  of  fermenta- 
tion and  putrefaction. 

2.  Potassium  sulphocyanide  does  not  possess 
any  appreciable  antiseptic  action  even  in  the 
greatest  strength  in  which  it  is  found  in  the 
human  mouth. 

3.  Growths  of  bacteria,  and  fermentative 
and  putrefactive  processes,  take  place  in  the 
oral  mucus  quite  as  readily  as  in  the  mixed  saliva 
of  the  same  persons,  if  not  more  so. 

4.  The  saliva  of  immunes  develops,  in  the 
presence  of  carbo-hydrates,  on  an  average,  a 
little  less  acid  than  that  of  highly  susceptible 
persons ;  the  difference  is,  however,  not  con- 
stant, and  not  sufficiently  marked  to  account 
for  the  great  differences  of  susceptibOity. 

According  to  Michaels,  variations  in  the 
standard  of  health  make  corresponding  changes 
in  the  composition  and  reaction  of  saliva. 
\Vlien  the  saliva  is  normal  there  is  immunity  to 
caries,  when  abnormal  the  teeth  show  various 
changes  as  an  effect  (13).  Hugenschmidt,  how- 
ever, came  to  the  conclusion  that  the  antiseptic 
action  of  saliva  is  most  problematical. 

If,  however,  there  is  still  any  doubt  as  to  the 
reliability  of  the  conclusions  of  such  investi- 
gators as  Miller  and  Hugenschmidt,  opinions 
may  be  formed  from  other  considerations.  At 
least  it  may  be  said  that  if  there  is  any  antiseptic 
action  m  the  saliva  it  mvist  be  exceedingly  weak, 
and  in  view  of  the  fact  that  the  mouth  of  man, 
and  animals  also,  whether  susceptible  or  immune 
to  caries,  always  contains  micro-organisms  in 
abundance,  it  may  be  doubted  whether  the 
search  for  antiseptic  properties  in  saliva  is  likely 
to  lead  to  positive  results. 

But  it  does  not  necessarily  follow  that  because 
the  saliva  is  not  antiseptic  it  is  not  antagonistic 
to  the  uiception  of  caries  ;  thus  the  alkaline  salts 
may  to  a  certain  extent  inhibit  the  carious 
process  ;  and  Joseph  Head  comes  experimentally 
to  the  conclusion  that  the  saliva  has  decided 
powers  of  protecting  the  teeth  from  acid  decal- 
cification, which  can  hardly  be  e.xplaitied  by 
its  contained  alkaline  salts.  In  this  there  may 
be  a  partial  explanation  of  the  fact  that  the 
starches  are  less  harmful  to  the  teeth  than  the 
sugars,  because  starch  cannot  give  rise  to  acid 
fermentation  except  when  incorporated  with 
saliva,  while  sugar  is  convertible  into  acids 
solely  by  the  action  of  micro-organisms. 

It  has  been  contended  b\'  F.  VV.  Low  that 
sulphocyanide  of  potassium  prevents  the  in- 
ception of  caries  because  it  is  a  solvent  of 
the  gelatinous  plaques,  or  that  it  inhibits  the 
plaque  formation  which,  it  is  held,  precedes  the 


292 


decalcification  of  the  enamel  (I).  This  subject 
has  not  been  fully  worked  out,  however,  and 
the  results  are  in  a  certain  proportion  of  cases 
conflicting  (27). 

Similarly,  the  class  of  micro-organisms  con- 
tained in  the  mouth  may  be  influenced  by  the 
saliva  and  mucus.  The  albuminous  mucus, 
salivary  corpuscles,  and  desquamated  epithe- 
lium, form  a  nutrient  medium  for  certain 
bacteria,  which  find  albuminous  material  the 
most  suitable  soil  for  tlieir  growth  ;  and  as  there 
is  no  carbo-hydrate  (normally)  secreted  by  the 
salivary  or  mucous  glands,  bacteria  that  find 
their  nutrient  medium  in  carbo-hydrates  are 
not  encouraged  ui  their  development.  It  may 
be  presumed  from  this,  and  from  the  fact  that 
the  fermentation  set  up  by  saliva  rich  in  mucus 
gives  place  more  rapidly  to  putrefaction,  that 
mucus  contains  a  relatively  larger  proportion 
of  saprogenic  bacteria  than  the  clear  saliva. 
The  glutinous  coating  of  a  somewhat  slippery 
nature  (the  basis  of  which  is  probably  mucin) 
to  be  found  on  the  less  rubbed  parts  of  the  teeth 
may  also  help  to  prevent  the  lodgement  of 
certain  food  particles,  and  thus  protect  the  teeth. 
The  nature  of  this  coating  is  no  doubt  very 
variable.  It  must  contain  different  species  of 
bacteria,  but  except  when  it  is  habitually  bathed 
in  fermentable  carbo-hydrates  tliese  bacteria 
are  probably  not  of  a  pronouncedly  acid-forming 
character ;  and  being  somewhat  imjaegnated 
with  saliva  and  salts,  \\hich  when  excessive  in 
amount  result  in  the  coatmg  becommg  soft 
tartar,  it  is  no  doubt  inimical  to  the  carious 
process.  When  tested  witli  litmus  paper  this 
coating  shows  a  distmctly  alkaline  reaction, 
and  when  it  is  artificially  brushed  away  from 
the  necks  of  the  mcisors,  canines,  and  pre- 
molars, these  teeth  appear  to  sliow  a  distinct 
predisposition  to  become  carious.  A  totally 
different  view  of  the  significance  of  this  coating 
is  held  by  Black  (3).  He  strongly  suspects  that 
this  glutinous  deposit  may  afford  coverings, 
which  will  shield  micro-organisms  and  their 
products  from  the  washmgs  of  the  saliva.  But, 
inasmuch  as  carbo-hydrates  are  presented  to 
the  outside  of  this  slippery  coating,  they  are 
liable  to  be  washed  away  altogether ;  it  thus 
seems  difficult  to  see  how  this  coatmg  can  aid 
the  micro-organisms  in  the  retention  of  acid  in 
contact  with  the  teeth.  It  should  be  noted  that 
this  glutinous  coating  is  entirely  different  from 
the  gelatinoid  plaques  formed  by  certain  micro- 
organisms, and  from  the  gummy  coatmg  which  is 
formed  by  the  mannitic  fermentation  of  cane- 
sugar.  This  latter  coatmg  is  highly  favourable 
to  the  inception  of  caries,  because  it  prevents  the 
saliva  diluting,  or  washing  away,  the  acid  formed 
from  the  sugar  under  the  gummy  coating. 

In  general,  it  should  be  noted  that  the  saliva 
and  mucus  are  secreted  in  quantity  and  quality 


proportionate  and  appropriate  to  the  necessity 
for  the  removal  from  the  mouth  of  certain  sub- 
stances, wliich  if  they  lodged  unduly  would  be 
injurious  to  the  teeth.  Thus,  acids  and  carbo- 
hydrates, more  especially  the  sugars,  stimulate 
a  copious  flow  of  saliva.  Caries  may  be  said, 
in  general,  to  be  mduced  by  those  agencies  that 
hinder  the  cleansmg  action  of  the  saliva,  such 
as  the  depth  of  the  crevices  of  the  teeth,  or  the 
nature  of  the  food  itself — for  example,  excess 
of  sugar,  or  absence  of  fibrous  matter,  «hich 
during  mastication  helps  the  saliva  to  reach 
relatively  inaccessible  crevices  in  the  teeth. 

SUSCEPTIBILITY  AND  IMMUNITY 

Disappointment  may  be  felt  that  the  present 
knowledge  of  tlie  chemical  constitution  of  the 
teeth  and  of  the  oral  secretions  does  not  throw 
mucli  light  on  the  question  why  the  teeth  in  some 
moutlis  succumb  to  caries  while  in  others  they 
remain  free  from  this  disease,  and  tliat,  notwith- 
standing the  most  persistent  and  careful  investi- 
gations, the  question  of  "  susceiJtibUity  "  and 
"  immunity  "  is  still  as  far  from  solved  as  ever. 
But  the  negative  results  of  these  investigations 
appear  to  confirm  the  beliefs  of  those  who  think 
tliat  the  existence  of  susceptibility  and  immunity 
has  been  assumed,  \\hen  a  simple  confession 
of  lack  of  knowledge  of  the  aetiology  of  the  dis- 
ease was  alone  justified.  Whetlier  in  the  future 
anything  at  all  analogous  to  susceptibility  and 
immunity,  as  iniderstood  in  medical  literature, 
may  be  discovered,  Ls  doubtful.  At  all  events, 
at  the  present  time  such  discovery  has  not  been 
made,  and  in  the  present  state  of  knowledge 
susceptibility  or  immunity  should  never  be 
assumed,  at  least  untU  all  the  conditions  that 
are  known  to  promote  the  undue  lodgement 
of  fermentable  carbo-hydrates  have  been  mvesti- 
gated.  Unless  the  well-known  conditions  that 
predispose  to  the  undue  lodgement  of  food  are 
included,  such  as  pits,  fissures,  malarrangement 
of  the  teeth,  arrested  flow  of  saliva,  etc., 
probably  it  is  umiecessary  to  believe  that  there 
is  any  appreciable  susceptibility  and  immunity 
to  caries  at  all.  It  has  been  seen  that  what 
was  once  considered  hereditary  predisposition 
is  now  recognized  to  be  entirely,  or  almost 
entirely,  a  matter  of  similarity  of  environment 
in  families,  and  even  in  races  ;  and  this  was  what 
most  necessarily  demanded  the  assumption  of 
a  con.stitutional  susceptibility  to  the  disease. 
Since  the  kinds  of  differences  in  foods  and 
dietetic  customs  that  lead  to  different  results  as 
regards  caries  have  become  more  accurately 
known,  it  has  been  recognized  that  what  once 
would  have  been  attributed  to  susceptibility 
and  immunity  may  now  be  attributed  to 
variations  in  diet  and  dietetic  habits.  Those 
who   assume   that   susceptibility   or   immunity 


293 


results  from  the  constitution  of  the  saliva  are 
confronted  with  the  fact  that  caries  is  a  markedly 
local  disease,  and  may  be  advancing  rapidly  in 
some  teeth  while  it  is  actually  becoming  arrested 
in  others.  Indeed,  in  one  single  tootli  the 
greater  part  may  frequently  show  arrested 
caries  \\hile  at  one  or  two  points  caries  may  be 
actively  progressing. 

Under  the  impression  that  there  was  practi- 
cally no  such  thing  as  inherent  or  constitutional 
susceptibility  to  caries — no  matter  how  much 
the  parents  might  have  been  afflicted  \\ith  the 
disease, — and  basing  a  system  of  prevention  on 
the  aetiology  of  the  disease  as  presented  in  these 
pages,  the  writer  persuaded  the  parents  of  four- 
teen infant  children  to  adopt  the  method  he  sug- 
gested and  to  test  it.  In  every  one  of  these  cases 
the  children  \\ere  free  from  all  traces  of  caries 
at  ages  varying  from  five  to  seven  years  (38). 

RELATIVE  LIABILITY  OF   DIFFERENT  TEETH 
TO  CARIES 

The  relative  liability  of  the  various  teeth 
to  caries  is  a  subject  that  has  received  con- 
siderable attention.  Generally  the  relative  fre- 
quency of  caries  in  different  teeth  has  been 
deduced  from  the  number  of  extractions  of 
particular  teeth  on  account  of  caries.  Con- 
sidered in  this  way  there  are,  of  course,  sources 
of  inaccuracy;  thus  a  first  molar,  for  example, 
is  likely  to  cause  much  more  severe  toothache 
than  a  third  molar,  because  of  its  lial)ility  to 
become  carious  in  early  life ;  this  would  lead 
more  certainly  to  its  extraction.  80  again, 
carious  third  molars  are  more  likely  to  remain 
during  life ;  or,  indeed,  they  may  never  have 
erupted  at  all  when  death  is  premature.  Never- 
theless, on  the  whole  a  fairly  good  general  know- 
ledge of  the  prevalence  of  caries  in  particular 
teeth  may  be  arrived  at  in  this  \\ay.  The 
following  analysis  of  over  30,000  extractions 
made  by  Wallis  and  Pare  indicates  the  relative 
frequency  of  caries  in  the  various  teeth  (33. 
p.  229)— 

Per  C«nt. 
1st  upper  molar  ....      18'7 
1st  lower  molar  ....      17'4 
2nd  lower  molar.         .        .        .      11-62 
2nd  upper  premolar    .        .        .        8-33 
2nd  upper  molar         .        .        .        8'04 
1st  upper  premolar     .        .        .       7'62 
2nd  lower  premolar    .        .        .        5-58 
3rd  lower  molar  ....       4-4 
3rd  upper  molar.         .        .        .        4-38 
Upper  lateral  incisor  .        .        .        3' 37 
1st  lower  ])remolar      .        .        .        3-07 
Upper  canine       ....        286 
Upper  central  incisor .        .        .       2'51 
Lower  canine       ....  '78 

Lower  lateral  incisor  .        .        .  -62 

Lower  central  incisor.        .        .  '44 


From  the  foregoing  table  it  may  be  observed 
that  the  teeth  most  predisposed  to  caries 
are  those  that  tend  to  induce  the  prolonged 
lodgement  of  food  and  micro-organisms.  Thus, 
for  example,  the  lower  incisors  and  canines 
are  particularly  unlikely,  both  from  the  manner 
in  which  they  cut  through  the  food  and  from 
their  shape,  to  favour  the  lodgement  of  food, 
whUe  the  molars  on  the  other  hand  are  par- 
ticularly liable  to  induce  the  undue  lodgement 
of  food,  and  consequently  to  become  carious. 
Further  comment  on  this  aspect  of  the  subject 
(36)  is  hardly  necessary,  for  in  general  it  may  be 
said  that  if  the  movements  of  the  jaws,  lips, 
cheeks,  and  tongue,  together  with  the  normal 
forms  and  arrangement  of  the  teeth  with 
regard  to  each  other  and  the  surrounding 
mucous  membrane,  are  considered,  it  is 
obvious  that  the  lial)ility  of  the  various 
teeth  to  caries  is  just  what  might  be  de- 
duced from  a  consideration  of  the  aetiology  of 
the  disease  as  already  set  forth.  If,  further, 
note  is  taken  of  the  parts  of  the  teeth  (3)  tliat 
are  most  frequently  attacked,  the  conclusion 
is  deduced  that  in  proportion  to  the  relative 
liability  of  any  particular  part  of  a  tooth  to 
lodge  food,  so,  to  a  corresponding  degree,  is 
dental  caries  likely. 

In  conclusion,  a  word  maybe  said  with  regard 
to  the  cause  of  caries  from  the  patient's  point 
of  view.  Patients  constantly  ask  why  the  teeth 
of  the  present  generation  are  so  bad,  and 
dentists  should  always  be  willing  to  answer  the 
question.  But  the  intelligent  layman  only 
wants  to  know — and  ought  accurately  to  be  told 
— important  points.  Consecjuently  he  need  not 
be  confused  with  an  exposition  of  conditions 
that  are  present  whether  the  disease  occurs  or 
not.  To  him  the  cause  of  a  disease  is  that  or 
those  controllable  antecedents,  which  being 
present,  the  disease  invariably  follows.  Atten- 
tion should  therefore  be  directed  to  the  abnormal 
or  prolonged  lodgement  of  fermentable  carbo- 
hydrates hi  the  crevices  of,  and  between,  and 
about,  the  teeth,  for  this  condition  being 
present,  the  disease  will  sooner  or  later  arise. 
It  is,  moreover,  the  alterable  condition  that  is 
of  importance  from  the  point  of  view  of  preven- 
tion. This '  condition  explains  whj'  the  teeth 
of  the  present  day  are  so  bad,  for  the  cooked 
and  prepared  foods  as  so  generally  consumed 
tend  to  lodge  unduly  and  undergo  fermentation 
under  circumstances  that  lead  to  the  destruc- 
tion of  the  teeth.  Technical  knowledge  is  not 
really  required  to  appreciate  the  cause  of  caries 
when  presented  thus,  and  it  is  of  cour.se  the  duty 
of  the  profession  to  the  public  to  see  that  they 
do  become  acquainted  with  the  knowledge 
that  for  their  own  welfare  thev  require. 

J.  s  .w. 


294 


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Turner,  J.  G.  Causes,  Effects,  and  Treatment,  of 

Dental  Diseases  in  Childliood.    Brit.  Med.  Jour., 

1907,  p.   1488. 
W.allace,  J.  Sim.     Cause  and  Prevention  of  Decay 

in  Teeth,  p.  7. 
Wallace,  J.  Sim.     Supplementary  Essays  on  the 

Cause  and  Prevention  of  Dental  Caries,  p.  46. 
Wallace,  J.  Sim.     Diet  in  Infancy  and  Childliood. 

Brit.  Dent.  Jour..  1908,  Vol.  XXIX,  p.  641. 
Wallace,  J.  Sim.    The  Prevention  of  Dental  Caries, 

p.  33. 
Watson,  Chalmers.     Meat  Diet  and  the  Teeth. 

Lancet,  1907,  Vol.  I,  p.  119. 
fl^EisM.ANN,  A.     The  Germ  Plasm,  p.  20. 
Williams,  L.     Formation  and  Structure  of  Dental 

Enamel,  p.  79. 


CHAPTER  XIV 

THE    PATHOLOGY   OF   DENTAL   CARIES 


The  process  and  progress  of  dental  caries — 
essentially  external  in  its  origin — is  one  of 
disintegration  and  loss  of  substance  of  the  teeth, 
prodnced  and  accompanied  by  chemical  means 
and  bacterial  action  in  the  mouth — changes 
which  can  be  experimentally  repeated  in  vitro. 

Its  commencement  is  clinically  noted  by  a 
softenmg  of  a  mmute  portion  of  the  hard 
circumference  of  the  enamel,  which  generally. 


whether  it  be  occlusal  or  mterstitial,  is  easily 
detected  by  the  carefid  examination  with  an 
explorer  of  the  fissure,  sulci,  pits,  and  the  in- 
equalities of  surface.  The  presence  of  a  small 
area  of  discoloration  does  not  necessarily  imply 
the  mception  of  the  condition.  If  situated  on 
the  coronal  portion,  this  would  appear  to  indicate 
some  colour  change  in  Xasm^-ths  membrane, 
either  by  the  action  of  cliromogenic  bacteria,  sucli 
as  the  liacillu.s  lititiejuckns  /luurcscens  molilis  or 


jwn-motilis,  the  Bacillus  prodigiosus,  the  Staphy- 
lococcus pyogenes  aureus  or  citreiis  ;  or  by  adven- 
titious materials  taken  into  the  moutli,  such  as 
the  oil  of  nicotine  ;  or  by  an  organic  change  due 
to  the  perversion  of  the  salivary  secretions. 

On  approximal    surfaces,  as  for  example  in 

the    premolars,    it    is    common    to    note    that 

whereas,  say,  a  cavity  of  "  decay  "  has  occurred 

on  the  distal  portion  of  the  first  premolar,  there 

is  no  actual  breach  on  the  medial  aspect  of  its 

posterior  neighbour,  but  that  a  more  or  less 

small  area  of  brown  or  black  stain  Ls  observed. 

This  is,  probably,  merely  a  superficial  chromatic 

alteration,  which  is  of  little  or  no  importance. 

The  first  real  indication  of  the  onset  of  caries 

is,  to  repeat,  the  decalcification  of  the  enamel, 

whereby  the  fine  extremity  of  an  explorer  can 

enter  the  sufficiently  disintegrated  tissue. 

The  softenmg  may  be,  and  often  is,  accom- 
panied by  a  pigmentation,  or  loss  of  translu- 
cency  or  polish  of  the  parts.  On  exposed,  fiat, 
or  convex  surfaces  an  opaque  condition  may 
obtain.  In  the  fissures  and  pits  of  the  occlusal 
or  buccal  surfaces,  especially  in  the  molar 
region  of  the  dental  arches,  the  former  changes 
are  frequently  seen  ;  and  in  the  later  stages  the 
white  opacity  itself  may  assume  a  greyish  or 
more  or  less  pronounced  brown  or  yellow  tinge. 
The  "bacterial  plaques"  of  some  authors, 
notably  Black  and  Leon  Williams,  are  believed 
to  be  due  to  the  zoogloea  formations  of  masses 
of  bacteria,  which,  collecting  in  favourable 
situations,  are  able,  by  a  precipitation  of  muci- 
laginous compounds,  to  focus  in  a  more  or  less 
widespread  but  yet  well-defuied  fashion  the 
operations  of  the  destructive  agencies  (15). 

But  all  writers  do  not  recognize  the  existence 
of  these  so-called  plaques,  as  such,  and  Kirk  has 
recently  shown  that  it  is  possible  to  manufac- 
ture bacterial  plaques  to  any  size  or  extent  (8). 
If  allowed  to   continue   unchecked,   dental 
caries  proceeds  at    a  varying  rate,  m  the  same 
mouth,    and   in   similar   teeth;   or   it    becomes 
spontaneously  arrested.     If  the  former  occurs, 
the  loss  of  the  enamel  at  the  original  pouit  of 
entrance  of  the  destroying  medium  is  succeeded 
by  invasion  of  the  dentine,  when,  on  account  of 
its  tubular  character,   the  condition  advances 
much  more  rapidly,  extendhig  downwards  and 
laterally,    and    thus    undermining    the    enamel 
to  a  certam  extent.      If  it  still  continues,  areas 
of  dentine   become  devastated  and  disappear, 
295 


296 


and  subsequently  the  enamel,  having  been 
deprived  of  its  support,  fractures  at  its  edge, 
and  shares  the  same  fate. 

If  tlie  condition  is  arrested,  through  mcreased 
physiological  resistance  of  the  parts  as  a  conse- 
quence of  an  amelioration  of  the  health  of  the 
individual,  the  process  and  progress  simul- 
taneously cease,  and  the  teeth,  denuded  of  the 
main  portions  of  their  crowns,  become  perman- 
ently discoloured,  and  do  not  admit  of  penetra- 
tion by  the  point  of  a  steel  instrument,  whUe  the 
previous  softness  of  the  tissues  now  gives  place 
to  a  polished  density  which  is  truly  remarkable. 


Fig.  388. — An  early  stag<^  in  cariet: 
E,  Enamel ;   D,  Dentine.      X 

MICROSCOPICAL    PHENOMENA 

Nasmyth's    Membrane    in    Carles. — It    is    not 

known  whether  tlie  translucent  pellicle  of 
Nasmyth's  membrane  (its  outermost  epithelial 
lamma  of  cells  is  a  negligible  structure  where 
caries  is  concerned)  becomes  peptonized  by  the 
bacterial  action.  It  is  highly  resi.stant  to  acids. 
If,  however,  it  is  of  the  same  chemical  constitu- 
tion as  the  sheaths  of  Neumann  in  the  dentine, 
it  is  capable  of  being  acted  upon  by  the  enzymes 
of  the  micro-organisms  and  split  up  and  dis- 
solved, probably  with  the  production  of  a  small 
quantity  of  amido-acetic  acid.  The  role  played 
by  Nasmyth's  membrane  with  regard  to  caries 
is  not  at  present  understood.  It  is,  however, 
extremely  probable  that  were  tliis  tissue  to 
remain  intact  on  the  surface  of  the  enamel,  no 
penetration  by  micro-organisms  could  take 
place.  It  is  too  thick,  measuring  generally 
50  /x  in  thickness,  not  1  /x  or  2  /x  as  KoUiker 


described ;  but  it  is  so  loosely  adherent  to  the 
periphery  of  the  enamel,  that  it  is  extremely 
easily  damaged  by  mechanical  agencies,  and 
bacteria  are  at  once  brought  into  immediate 
contact  with  the  enamel.  In  the  writer's 
opinion,  however,  it  constitutes  the  first  line 
of  defence  against  dental  caries. 

It  may  be  argued  that  on  approximal  sur- 
faces, where,  it  may  be  surmised,  no  traumatism 
could  exercise  much,  if  any,  effect  on  the  teeth, 
and  m  the  depth  of  pits  and  fissures,  etc., 
caries  should  never  be  found.  It  is  common 
knowledge  that  interstitial  caries  is  of  more 
frequent  occurrence  than 
that  on  the  labial,  buccal, 
or  lingual  surfaces.  This 
frequency  may  be  ex- 
plained by  the  belief 
that,  once  having 
effected  an  opening 
through  the  pellicle  of 
Nasmyth's  membrane — 
say,  for  instance,  on  the 
summit  of  a  cusp  of 
a  premolar — the  micro- 
organisms would  quickly 
travel  down  to  the  future 
site  of  caries.  Black's 
gelatinous  plaques,  which 
both  he  and  Leon  Wil- 
liams lay  so  much  stress 
upon,  are  probably  no- 
thing more  nor  less  than 
fragments  of  this  mem- 
brane, which,  covered 
with  bacteria,  still  re- 
main adherent  to  the 
surface  (1). 

Walkhoff  has  demon- 
strated the  presence  of 
organic  pigment  on  Nasmytirs  membrane  (14). 
This  is  probably  identical  with  tlie  stain  seen 
sometimes  on  the  teeth  of  chUdi'en,  which  does 
not  necessarily  indicate  the  first  stage  of  caries. 
It  is  probably  generated  by  the  chromogenic 
bacteria  before  mentioned,  and  is  more  adherent 
to  the  translucent  pellicle  of  the  membrane 
than  to  the  free  surface  of  the  enamel  itself, 
occurring,  curiously  enough,  most  frequently 
on  the  labial  surfaces  of  the  maxillary  incisors 
— a  fact  which  would  suggest  that  the  colour 
was  due  to  the  action  of  an  air  micro- 
organism. 

The  {precise  effects  of  caries  on  Nasmyth's 
membrane  remain  as  yet  unknown.  Many 
text-book  statements  are  purely  conjectural. 
Pickerill  believes,  perhaps  with  some  reason, 
that  it  acts  as  a  dialysing  membrane  to  certain 
structures,  which  may  disintegrate  the  surface 
of  the  enamel,  and  pave  the  way  for  carious 
changes — an  hypothesis  that  is  apparently  sliared 


of  enamel 
45. 


297 


by  Tomes  and  Nowell  (12).     But  the  difficulties 
of  proof  are,  at  present,  exceeding!}'  great. 

Microscopically  there  is  nothing  to  distinguish 
the  structure  of  the  component  parts  of  the  mem- 
brane in  the  case  of  normal  tLssue,  and  in  the 
case  of  that  associated  witli  caries. 

Enamel 

A. — On    the    Occlusal    Surfaces.     In    vertical 
section   of  the  crowns   of  teeth   in   which   the 
earliest  phenomena  of  caries  appear,  it  is  obvious 
that  these  occur  in  the  neighbourhood  of  the 
fissures.     Examination  of  a  deep  fissure  nearly 
prolonged    to    the    amelo-dentiiial     junction, 
reveals  the  presence  of  broad  brown  patches 
similar  to  the  "  white  spot  "  surrounding  the 
entrance.      These  extend  some  distance  out- 
wards.    Beneath    any    remaining    shreds    of 
Nasmyth's  membrane  the  colouration  is  not 
so  intense  ;   it  is  the  innermost  region  of  the 
affected  area  that  is  most  deeply  pigmented. 
Beyond  this  band  an  area  of  unstained  tLssue 
supervenes   between   it  and  a  large  territory 
of  coloured   enamel.     In  shallow  pits  with  a 
less   truncated  aperture  the   pigmentation   is 
more  pronounced,  and  there  is  but  little  lateral 
extension ;    it    may  happen  that  the  area   of 
unstained    tissue    is    absent.     The    sub-lying 
dentinal  tubules  are  rendered  inconspicuous, 
their  refractive  indices  approximating  to  that 
of  the  matrix ;  the  colourless  area  may,  how- 
ever, be  present. 

As  loss  of  surface  takes  place  the  discolora- 
tion increases,  until  the  enamel  that  .still 
remains  undisintegrated  assumes  a  yellowish 
or  cinnamon  colour  ;  it  thus  occupies  the  base. 
so  to  speak,  of  a  triangle,  the  apex  of  which 
is  directed  downwards  towards  the  dentine. 
The  figure  itself  is  formed  by  the  distribution 
of  the  dentinal  tubules,  which  are  occluded 
with  air  and  debris,  as  they  show  up  most 
clearly  under  a  low  power  objective  of  the 
microscope.  There  may  be  an  actual  separa- 
tion of  enamel  and  dentme  at  their  junction. 
Fragments  of  Nasmyth's  membrane  always 
remaui  at  the  bottom  of  a  pit  or  fissure. 

B. — On  Approximal  Surfaces,  and  on  the 
labial,  but  seldom  on  the  lingual  aspects  of 
the  teeth,  the  phenomena  of  '"  white  spots  " 
appear.  The  pathological  process  is  probably 
identical  with  that  just  described.  The  ap- 
pearances presented  are  as  follow  :  A  band  of 
pigmentation  of  varying  thickne.ss  extends 
into  tiie  enamel  in  an  arcuate  form,  having  on 
both  sides  paler  zones,  of  which  the  innermost 
is  perhaps  the  more  translucent  of  the  two. 
Whether  this  represents  a  decalcification  or 
not,  is  difficult  to  determhie,  but  it  probably 
does,  the  pigmented  band  being  due  most 
probably  to  post-mortem  changes  common  to 
all  dead  matter.  The  enamel  rods  are  them- 
selves exceedingly  granular,  having  lost  a 
10* 


large  part  of  their  characteristic  structure. 
Individually  they  are  pigmented,  and  there  is 
irregular  fusion  of  their  enamel  globules.  By 
transmitted  light  a  "  white  "  spot  is  rendered 
a  dark  spot,  as  light  penetrates  but  feebly 
through  the  enamel  rods  and  their  cementing 
substance. 

Not  all  "  white  spots  "  are  evidences  of 
caries.  Those  seen  in  permanent  teeth  may 
have  a  different  origin.  J.  G.  Turner  has 
shown  that  a  septic  condition  of  the  deciduous 
series  wUl,  at  times,  leave  a  mark  upon  the 
crowns  of  their  successors.     He  attributes  many 


Fig.  389. — Caries  of  the  enamel. 
II,  Micro-organisms;  E,  DecalciBed  enamel.      X  90. 

of  the  discoloured  patches  classified  as  "  white 
and  coloured  spots  "'  to  this  cause  (13). 

The  means  by  which  the  enamel  rods  beconie 
detached  from  one  another,  and  thus  begin 
to  fall  away,  is  the  action  of  the  caries-producing 
micro-organisms.  A  multitudinous  tunnelling 
of  the  tLssue  of  parallel-sided  or  V-shaped 
channels  of  different  lengths  penetrates  the  line 
of  least  resistance,  viz.  that  of  the  cementing 
substance,  and  not  at  first— unless  the  tissue 
is  incompletely  developed— the  actual  axes 
of  the  rods.  'These  channels  at  their  outer 
ends  mav  measure  more  than  5  /u,  in  width  ;  but 
this  naturally  in  acute  caries  Ls  ([uickly  exceeded 
in  amount,  and  in  chronic  conditions  less  rapidly. 
The  morphological  detaUs  of  the  rods  undergo 


298 


less  change  in  the  former  than  in  the  latter 
class  of  caries,  where  they  assume,  according  to 
Leon  Williams,  a  "sponge-like  "  structure,  and 
viewed  by  transmitted  light  appear  to  be  greyish 
or  discoloured,  and  by  reflected  light,  white. 
By  the  absence  or  presence  of  colour,  therefore, 
an  acute  or  chronic  condition  may  usually  be 
diagnosed.  As  caries  advances,  the  transverse 
striae  of  the  individual  rods  become  more 
pronounced. 

"  Secondary  enamel  decay  "  is  thus  termed 
from  the  fact  that  an  extension  from  within 
outwards  of  the  carious  processes  has  taken 
place.  It  consists  almost  enthely  of  broken- 
down  rods  and  ma.sses  of  bacteria.  Between 
this  area  and  that   just  described,  the  changes 


M,   Micro-organisms  in  a  tube ;  LF,  Liquefaction 
focus.      X  450. 


in  the  structure  of  the  enamel  are  truly  re- 
markable. Tlie  rods  have  lost  their  outlines, 
are  exceedingly  granular,  are  broken  up,  and 
are  either  isolated  or  confluent — all  evidences 
of  the  structure  of  a  zone  of  complete  de- 
calcification. 

Dentine 

The  pathological  variations  in  the  dentine, 
similarly  to  those  of  enamel,  are  concerned 
with  two  distuict  chemical  and  histological 
elements.  Unlike  tho.se  of  enamel,  however, 
the  presence  of  tubes  renders  the  process, 
perhaps,  more  easily  comprehensible.  The 
changes  affect  the  walls  of  the  dentinal  tubes, 
the  matrix,  and  the  inter-globular  spaces. 


The  tubular  nature  of  human  dentine  permits 
the  free  entry  of  bacteria,  and  as  the  process 
deepens,  its  rate  increases,  on  account  of  the 
gradual  enlargement  of  the  tubes  as  they 
approach  the  pulp.  Tlirough  the  peptonizing 
action  of  the  bacteria,  the  sheaths  of  Neumann 
become  thickened,  their  elastin  being  probably 
converted  into  immeasurable  quantities  of 
amido-acetic  acid.  That  there  is  a  definite 
swelling  and  dilatation  of  the  sheaths  of  the  tubes 
admits  of  no  doubt,  the  thickening  being  due 
to  the  action  of  the  bacteria  on  the  walls 
themselves,  and  also  on  the  adjacent  matrix, 
which,  becoming  decalcified  and  therefore  soft, 
allows  the  expansion  of  the  diameters  of  the 
tubules. 

A  "liquefaction  focus"  is  an  area 
where  the  matrix  is  softened  to  such  an 
extent  that  the  collagen,  rid  of  its  lime 
salts,  has  probably  become  of  the  nature 
of  calcoglobulin.  The  tubules  here  are  so 
enlarged  that  apparently  the  mechanical 
accumulation  of  bacteria  and  their  pro- 
ducts causes  their  physiological  resistance 
to  be  diminished,  and  they  break  and  fuse 
with  their  neighbours.  Thus  are  pro- 
duced, in  the  fir.st  instance,  oval  or 
balloon-shaped  bodies  in  the  courses  of 
the  tubules,  and  usually,  but  by  no  means 
invariably,  with  the  longer  diameter  placed 
longitudmally. 

A  continuation  of  the  process  involves 
a  greater  number  of  tubules  and  a  more 
extensive  portion  of  raatri.x,  and  ultimately 
ends  in  tlie  formation  of  a  small  cavity. 
The  matrix,  at  all  times,  suffers  first ;  the 
tubules  are  secondarily  affected.  The 
microscopical  features  of  these  enlarged 
tubules  give  the  so-called  "  pipe-stem  " 
appearance  to  carious  dentine. 

The  chief  interest  in  the  changes  in  the 
matrix  lies  in  the  controversy  that  has 
arisen  over  the  cause  of  the  .so-called 
"translucent  zone".  Two  schools  of 
thought  have  occupied  themselves  with 
this  question  :  (i)  the  Vitalists,  who  consider  that 
it  represents  the  physiological  resistance  of 
dentme  to  morbid  changes,  being  due  to  an 
actual  calcification  of  the  dentinal  fibrils — the 
belief  of  Sir  John  Tomes,  Miller,  Walkhoff, 
Magitot,  etc. ;  and  (ii)  the  others,  who  deem  it 
an  area  of  partial  decalcification  produced  by 
the  advancing  army  of  bacteria,  with  consequent 
and  concomitant  obliteration  of  the  tubules, 
through  tlie  swelling  of  the  matri.x.  Wedl, 
Black,  Charles  Tomes,  Leber  and  Rottenstein, 
and  F.  J.  Bemiett,  among  others,  hold  this 
view. 

Into  this  diversity  of  opinion  it  is  unnecessary, 
here,  to  enter.  Suffice  it  to  say  that  the  facts 
connected   with   it    would   appear   to    be   that 


299 


around  the  cone-shaped  carious  region  there  is 
an  alteration  in  the  appearance  of  the  dentine, 
wiiicli  becomes  more  transparent  and  indicates 
an  increase  in  the  homogeneity  of 
the  tissues.  If  this  be  compared 
with  adventitious  dentine — which  is 
so  frequently  an  accompaniment  of 
dental  caries,  an  effort  on  the  part  of 
tlie  pulp  to  withstand  the  bacterial 
intrusion,  as  described  in  Chapter 
XVI — it  is  seen  that  it  possesses  the 
same  lustre  and  translucency,  prol)- 
ably  indicating  that  its  chemical 
constitution  is  similar,  if  not  identi- 
cal.    Translucent    zones    occur    at 


the  presence  of  opaque  zones  in  the  near  proxi- 
mity of  the  translucent  zone,  which  seem  to 
arise  from  the  uiclusion  in  the  tubules  of  certain 


times  in  abrasion  of  the  teeth.  It 
would  be  thought  that  all  doubt 
about  the  method  of  their  formation 
would  be  set  at  rest  by  ascertaining 
^^hethe^  the  tubules  were  patent  or 
otherwise — by  immersion  of  carious 
teeth  in  aniline  dyes  or  carmine 
solutions.  This  apparently  has  been 
done  by  the  advocates  of  both 
hypotheses,  with  the  astonishing 
result  that  both  admit  the  possi- 
bility of  the  staining  of  the  interiors 
of  the  tubules  in  many  instances. 

In  the  vanguard  of  the  advancing 
micrococci,  the  traversing  of  the  inter-globular 
spaces  by  the  tubules  can  sometimes  be  beauti- 
fully observed.     At  an  early  stace,  individual 


KiG.  391. — Mi<To-orguiusins  in  the  doiitinul  tubes. 
M,  Bacteria ;  LF,  Liquefaction  focus.      X  450. 


groups  of  tubule: 
cross  the  spaces. 

In  addition  to  the  above 


\\  ith  their  containing  bacteria 
Miller  has  described 


Fig.  392. — Caries  of  dentine. 
D,  Dentine ;  C,  Carious  tubes.      X  90. 

■■  irregular  angular  granules  "  ;  and  Sir  John 
Tomes  observed  rod-shaped  elements,  which  he 
believed  were  due  to  portions  of  the  "  con- 
solidated dentinal  fibrils  "',  and  also  certam 
"sliming  irregular  granules",  which  may 
be  a  deposit  of  lime  salts,  or  partake  of 
the  nature  of  fatty  material. 

The  three  last-named  phenomena  are  by 
no  means  constant :  in  fact,  the  writer  has 
never  been  able  definitely  to  recognize  in 
any  preparations  of  caries  of  the  dentine 
either  "  opaque  zones  ",  "  consolidated 
dentinal  fibrils  ",  or  "  shiny  irregular 
granules  ''. 

The  Micro-organisms  of  Dental  Caries 

The  micro-organisms  normally  found  in 
the  oral  cavity  of  man  are  of  all  kinds  : 
cocci  e.xLst,  perhaps,  most  abundantly,  but 
also  bacilli,  thread-forms,  sarcinae  and 
spirilla.  It  is  probable  that,  among  these, 
the  Streptococcus  pyogenes,  the  Staphylo- 
coccus pyogenes  aureus,  and  the  Diplococcus 
pneumoniae  are  the  commonest.  In  ad- 
dition, many  aerobic  and  non-aerobic 
sporing  bacilli  are  taken  in  through  the 
media  of  air,  water,  and  food. 

It  is  difficult  to  determine  with  any  degree 

of  accuracy  the  forms  and  biological  j)ro- 

perties  of  the  actual  producers  of  dental  caries  :  it 

is  so  easy,  even  w  ith  the  utmost  care,  to  obtain 

micro-organisms,  for  experimental  purposes,  that 


300 


are  incapable  of  causing  the  initial  decalcification 
of  the  enamel.   Nor  is  it  yet  ascertained  whether 


Fig.  393. — Caries  of  dentine. 
D,  Dentine ;   C,  Carious  tubes.      X  90. 

the  bacterial  factors  that  may  occasion  the 
dissolution  of  the  peripheral  hard  parts  of  the 
teeth  are  the  same  as  those  inhabitmg  the 
dentmal  tubules,  or  the  surfaces  of  carious 
cavities.  The  saliva  carries  with  it,  and 
sweeps  into  the  cavities,  adventitious  bacteria. 
Others  from  the  oral  mucous  membrane,  the 
gingival  troughs,  the  alveolar  "  pockets  ",  the 
tonsils  and  pharynx,  add  their  share  to  tlie 
varieties  of  the  oral  flora,  and  make  the  real 
discrimination  between  the  caries-producing 
and  the  non-caries-producing  organisms  diffi- 
cult to  determine.  In  the  microscopical  in- 
vestigation of  a  fragment  of  carious  enamel 
or  dentme,  multitudes  of  bacteria  are  seen; 
but  it  is  almost  impossible  to  affirm  with 
certamty  whether  those  present  are  such  and 
such  organisms.  Identification  is  often  im- 
possible. The  bacteria  of  caries,  as  Goadby  (4) 
points  out,  appear  to  be  influenced  very  largely 
by  their  environment ;  and  it  is  quite  possible 
that  the  actual  producers  of  the  softeners  of 
the  enamel  are  often  overwhelmed  by  the 
preponderating  growth  of  others,  which,  as 
secondary  agents    of    "dental    decay",    pene- 


trate the  dentinal  tubules  and  peptonize  their 

walls. 

Several  facts,  however,  would  seem,  in  all 
probability,  to  stand  out  pre-eminently.  The 
bacteria  ui  superficial  parts  are  aerobic  :  those 
beneath,  in  the  vanguard  of  the  ad  vane  mg 
host,  are  anaerobic  or  facultative  aerobic. 
Many  are,  as  yet,  incapable  of  cultivation  on 
the  ordinary  laboratory  media  ;  the  superfici- 
ally placed  bacteria  produce  digestive  enzymes, 
others  fermentation,  with  an  acid  reaction  ;  no 
liquefaction  of  undecalcified  dentine  probably 
takes  place  by  means  of  the  proteolytic  en- 
zymes :  and  finally  it  is  practically  impossible 
to  differentiate  between  pathogenic  and  non- 
pathogenic forms.  Emery,  in  WTiting  of  general 
immunity,  says  ;  "  It  is  a  most  marvellous 
natural  phenomenon  that  the  putrefactive 
bacteria  should  be  found  wherever  life  occurs, 
and  wherever  their  aid  may  be  required  to 
deal  with  the  protoplasm  when  dead,  and  that 
this  same  protoplasm  should  have  acquired 
such  potency  in  resistmg  their  attacks  whilst 
still  alive.  Absence  of  bacteria,  or  absence  of 
immunity,  are  alike  incompatible  with  animal 
life." 

"  Considerations  of  this  nature  lead  us  ",  he 
(  imtinues,  "  to  a  short  discussion  between  the 
|iathogenic  and  non-pathogenic  bacteria,  and 
we.  find  that  there  is,  theoretically,  none.  Any 
liacterium  will  produce  disease  if  it  grows  in 
the  tissues  of  the  living  body,  and  all  bacteria 


'■':i^^:j''>?^ 


mm 


Fig.  394. — Transverse  section  of  carious  dentine. 
C,  Micro-organisnas  in  tubes,      x  180. 

— those  growing  only  at  very  high  or  very  low- 
temperatures ,  or  on  media  very  poor  m  nitrogen, 
perhaps  excepted — will  do  so  if  the  necessary 


301 


degree  and  form  of  immunity  is  not  present. 
A  pathogenic  organism  is  one  which  can  grow 
in  the  living  tissues,  and  it  can  do  so  only 
because  those  mechanisms  of  immunity 
which  are  sufficient  in  the  case  of  the 
saprophytic  bacteria  are  powerless  to  resist 
it ;  but  ill  most  cases,  a  liigher  degree  of 
immunity  can  be  produced  artificially,  and 
the  microbe  in  question  then  becomes  non- 
pathogenic to  that  particular  animal.  So, 
too,  will  the  bacteria  ordinarily  regarded 
as  non-pathogenic.  Under  certain  circum- 
stances, some  of  whicli  are  known  and  some 
still  unknown,  the  resistance  of  the  body  or 
of  a  part  of  it  may  be  broken  down  to  such 
an  extent  that  these  organisms  may  gain 
access,  flourish,  and  give  rise  to  disease. 
Thus,  the  Bacillus  proteus  may  give  rise  to 
phlebitis,  growing  in  the  thrombosed  vein, 
and  giving  off  toxins  which  have  an 
injurious  action  on  the  ti.ssues  "  (3). 

If  these  data  are  remembered,  it  will  be 
at  once  obvious  that  the  intricacies,  such 
as  those  afforded  by  a  study  of  the  real 
caries-producing  micro-organisms  and  their 
actions,  are  very  great,  especially  when  one 
is  reminded  that  the  bacteria  of  the  diges- 
tive tract  enter  the  mouth.  At  present 
it  is  impossible  to  say  why  many  persons 
who  are  ignorant  of  the  necessities  of 
ordinary  oral  hygiene,  and  also  never 
perform  the  usual  dental  and  oral  toilet. 
are  free  from  dental  caries  ;  and  the  opinion. 


of  the  immune  individual  is  so  great  as  to  render 
their  action  inoperative,  is  purely  conjectural. 


Fig.  390. — A  late  stage  of  caries  of  the  dentine. 
C,  Cavity;  P,  Pulp-chamber.      X  45. 


Fig.  395. — Transverse  section  of  carious  dentine,      x  250. 

that  either  a  special  bacterium  or  group  of 
bacteria  provocative  of  dental  caries  may  e.xist, 
or  that  the  physiological  resistance  on  the  part 


As  far  as  is  known,  however — thanks 
largely  to  Miller,  Goadby,  and  others — it 
may  be  briefly  stated  that  the  micro-organ- 
isms foiuid  in  the  superficial  parts  of  carious 
dentine  are  either  liquefiers  of  that  tissue, 
when  it  has  already  been  decalcified  to  a 
certain  extent,  or  are  merely  acid-producers. 
To  the  former  groufj  belong,  in  alphabetical 
iirder,  the  Bacillus  furvus.  Bacillus  gingivae 
jii/ogenes,  Bacillus  liquejaciens  fluorescens 
tnotilis  ;  Bacillus  mesentericus  fuscus,  ruber, 
and  vulgatus  ;  Bacillus  plexiformis.  Bacillus 
suhiilis,  and  Proteus  vulgaris  :  to  the  latter, 
the  Sarcina  alba,  auranliaca,  and  lulea ; 
Staphylococcus  albus  and  aureus,  and  Strepto- 
coccus brevis.  Those  discovered  in  the  deeper 
layers  of  dentine  are  the  Bacillus  necroden- 
talis.  Staphylococcus  albus,  and  Staphylococcus 
brevis.  A  third  class  includes  the  chromo- 
genic  bacteria  mentioned  on  an  earlier  page. 
Of  the  above,  the  Bacillus  liquejaciens 
fluorescens  motilis,  the  Bacillus  plexiformis, 

and  the  Proteus  vulgaris  are  Gram-negative,  all 

the  others  being  Gram-positive. 

Round  the  edges  of  carious  surfaces  are  found 


302 


many  thread-like  forms.  These  often  include 
such  organisms  as  tlie  Leptothrix  innominata  and 
racemosa,  Leptothrix  buccalis  maxima,  the  Strepto- 
thrix  buccalis,  and  the  vibrios  described  as  the 
Spirillum  sputugenum,  and  Spirochaete  dentium, 
which  may  be  identical. 

Choquet  has  isolated  five  varieties  of  bacteria 
from  beneath  fillings  (2). 

Caries  of  Cementum. — Dental  caries  occurs 
less  frequently  here  than  in  the  two  other  hard 
tissues.  The  reasons  are  mainly  anatomical. 
If  the  periodontal  membrane  remams  in  situ 
over  the  roots,  and  if  it  becomes  inflamed,  or 
otherwise  undergoes  morbid  changes,  it  is 
possible — though  as  yet  not  demonstrable  nor 
demonstrated — that  a  bacterial  infection  might 


Fig.  -Ml 


-Vi-'i'i  ical  snclitm  t)l'  .■ti;iiii<]  J 
E,  Enamel;  D,  Dentine. 


X  90. 


pass  into  the  substance  of  tlie  cementum. 
Sections  can  be  obtained  for  microscopical 
examination  of  this  tissue  covering  the  dentine 
of  the  palatine  roots  of  maxillary  molars,  when, 
on  account  of  absorption  of  the  bone  of  their 
sockets,  and  denudation  of  the  sub-lying  parts, 
the  cementum  becomes  exposed.  A  certain 
amount  of  softening  occurs,  but  this  differs, 
physically  and  chemically,  from  the  like  phe- 
nomena that  are  seen  in  enamel  and  dentine, 
although  it  more  closely  approaches  that  in  the 
latter  tissue. 

Cocci  have  been  demonstrated  by  Gram's 
method,  in  these  circumstances,  in  the  short 
canals  in  which  the  Sharpey's  fibres  lie.  The 
means  of  penetration  is  more  or  less  mechanical. 
Small  cocci  gam  quite  an  easy  entrance  into  the 
widely-open  apertures  of  the  canals  and  proceed 


for  a  short  distance  only,  for  these  channels  are, 
roughly  speaking,  trumpet-shaped,  and  narrow 
down  very  rapidly  as  they  extend  inwards  to  the 
homogeneous  layer  of  the  cementum.     Thread- 
forms  have  never  been  seen  entering  the  canals. 
"  Arrested  "  Caries. — The  macroscopical  char- 
acteristics    are     recognized    without    difficulty 
by  the  dental  practitioner ;  but  little  is  known 
concerning  the  physical,  chemical,  and  histolo- 
gical phenomena,  or  their  courses.     The  enamel, 
dentine,  and  cementum,  together  with  the  pulp, 
may  all  be  influenced  by  the  condition.     For  if 
caries  has  advanced  but  little  in  a  tooth,  the 
enamel  is  often  partially  retained.     Permanent 
molars  afford  good  opportunities  for  the  exam- 
ination   of    the    microscopical    changes.     They 
should  be  treated  by  the  Koch- 
Weil  method,  which  here  pos- 
sesses the  advantages  of  en- 
abling   the    observer   to    dis- 
tinguish between  the  chemical 
and    physical    alterations    of 
teeth  affected   by   acute  and 
chronic  caries. 

In  such  cases  the  enamel  is 
stained  uniformly  for  varying 
depths.  In  its  widest  portions, 
certain  areas  over  the  cusps 
of  the  dentine  may  remain  un- 
coloured,  although  the  whole 
of  the  superficial  parts  of  the 
tissue  are  stained.  Under  a 
high  power,  the  stained  por- 
tions show  very  clearly — the 
cement mg  substance  between 
the  individual  rods  appearmg 
as  dim  black  longitudinal  Ihies 
running  in  a  parallel  direction 
on  a  red  background.  The 
transverse  striae  of  the  rods  are 
^ird  (-iinrs  ■'.  indistinguishable,    the    struc- 

tural alterations  giving  them  a 
homogeneous  appearance.  In 
the  unstained  areas,  the  boundaries  of  the  rods 
are  observed  without  any  difficulty,  but  they 
themselves,  while  losing  their  transverse  mark- 
ings, are  distinctly  granular.  The  brown  striae 
of  Retzius,  as  well  as  Schreger's  lines,  are  invisible 
in  stained  sections. 

Beneath  the  amelo-dentinal  junction,  which 
may  itself,  at  times,  be  pigmented,  a  thick  band 
of  unstamed  dentine  is  found.  Nearer  the  pulj], 
the  whole  of  the  dentine  is  coloured  a  bright 
carmine,  which  differs  in  intensity  from  the 
scarlet  of  the  enamel.  It  is  quite  prol^able  that 
the  cu'cumferential  dentinal  tubes  have  their 
lumina  comjjletely  obliterated,  for  their' out- 
lines are  absorbed  in  the  general  homogeneous 
appearance  of  the  matrix.  Here  and  there,  in 
many  places,  their  shapes  are  well  defined  by 
the  presence  of  broken  or  contiiuious  greyish  lines 


303 


filling  tlieir  interiors.  The  stained  portions 
contain  multitudes  of  delicate  granules  of  the 
staining  reagents. 

In  the  pulp,  adventitious  dentine  may  or  may 
not  be  found.  The  breach  of  surface  of  the  enamel 
does  not,  ho«  ever,  seem  to  produce  a  correspond- 
ing development  on  the  part  of  tlie  pulp  in  early 
cases,  because  the  formative  cells  of  the  latter 
organ  have  not  been  called  upon  to  provide  a 
physiological  barrier  to  tlie  carious  attack.  The 
pulp  is  not  inflamed.  If,  ho\\ever,  events  should 
occur  rapidly,  and  acute  conditions  should  super- 
vene upon  the  arrested  state,  the  usual  micro- 
scopical changes  of  acute  caries  are  evident. 

The  dentine  and  cementum  of  the  radicular 
portions  of  the  teeth  are  frequently  unstained, 
showing  changes  somewhat 
similar  to  those  of  senile 
teeth,  or  those  affected  by 
disease  of  the  periodontal 
membrane.  There  is  no  pene- 
tration of  reagents,  and  large 
uncoloured  areas  are  found. 

Defective  Formation  of 
Teeth. — The  developmental 
defects  of  enamel  may  or 
may  not  assist  the  process 
and  progress  of  caries.  Ac- 
cording to  the  envkonment, 
and  not  so  much  the  struc- 
ture of  enamel,  does  this 
occur.  Black  has  seen 
'"white  spots",  and  "dead- 
paper  wliite  "  enamel,  free 
from  caries ;  thLs  he  con- 
siders to  be  due  to  lack  of 
cementing  material  between 
the  individual  rods.  He 
wTites  :  '"This  condition  of 
the  enamel  had  not  rendered 
the  teeth  more  than  ordin- 
arily liable  to  caries,  etc." 

If  the  colouration  is  of  a 
dead  lustreless  character,  Nasmyth's  membrane 
is  absent ;   if  not,  it  is  present  as  usual. 

Unusual  Situations  for  Dental  Caries. — As 
throwing  some  light  on  the  aetiology  of  this 
condition,  it  is  necessary  to  observe  and  note 
cases  that  present  bacteriological  and  cliemical 
changes  in  parts  of  the  teeth  that  are  commonly 
unaffected,  viz.  the  admittedly  self-cleansing 
surfaces,  such  as  the  labial  aspects  of  the  anterior 
teetli,  the  extremities  of  the  pointed  cusps  of  the 
canines,  the  lingual  sides  of  the  cro\\iis  of  the 
mandibular  incisors,  etc.  The  writer  has  per- 
sonally observed  instances  of  caries  commencing 
to  attack,  among  others,  the  palatine  surface  of 
the  second  left  maxillary  permanent  molar  in  a 
mouth  otherwise  apparently  innnune  ;  the  lingual 
surface  of  the  left  maxillary  deciduous  incisor ; 
the  disto-buccal  surface  of  the  second  left  maxil- 


lary permanent  molar ;  the  labial  surface  of  the 
first  right  mandibular  permanent  incisor ;  and 
the  tip  of  the  maxillary  permanent  canine,  etc. 
The  collection  of  evidence  such  as  that  just 
adduced  is  much  needed  to  help  to  elucidate 
many  of  the  still  serious  problems  surrounding 
the  pathological  phenomena  of  dental  caries. 

A.  H-S. 
BIBLIOGRAPHY 

(1)  Black.     Operative  Dentistry,  Vol.  I,  1908. 

(2)  Choquet.     a     Study     of     Certain     Microbes     in 

Dental  Caries.  Proc.  Int.  Dent.  Cong.  Paris.  1900. 

(3)  Emery.     Immunity  and  Specific  Therapy,   1909. 

(4)  GoADBY.      The  Mycology  of  the  Mouth,   1903. 

(5)  Hewlett.     A  Manual  of  Bacteriology,  1898. 

(6)  Hopewbll-Smith.     The     Histology    and     Patho- 

Histology  of  the  Teeth  and  Associated  Parts,  1390. 


Fig.  398.- 


-Vertical  section  of  enamel  of  "  arrested  caries  ' 
E,  Enamel ;  D,  Dentine.      X  90. 


(7)  Hopewell-Smith.     The   Pathology   of   the   Pulp 

in  Relation  to  Clinical  Dental  Surgery.     Dental 
Cosmos,  1909,  Vol.  LI,  p.  13h6. 

(8)  Kirk.     A  Consideration  of  the  Question  of  Sus- 

ceptibility   and    Immunity    to    Dental    Caries. 
Dental  Cosmos.  1910,  Vr>l.  LII,  p.  729. 

(9)  Low,    F.   W.      Prophylactic   Value  of   Potassium 

Sulphocyanate  in  Saliva.     Dental  Cosmos,  1911. 
Vol.  LIII   p.  12(59. 

(10)  Miller.      The    Micro-Organisms    of    tlie    Human 

Mouth,    1894. 

(11)  Rose.      Deficiency    of     Mineral    Salts    and    De- 

generacy.    Dental  Cosmos,  1909,  Vol.  LI. 

(12)  Tomes     and     Nowell.     A     System     of     Dental 

Surgery,   1906. 

(13)  Turner,     J.     G.     Aetiology    and     Pathology    of 

Defects     of    Teeth     of     Children.     Brit.     Med. 
Jour.,  No.  23,   1907.  p.  1488. 

(14)  Walkhoff.     Mikrophotographischcr  Atlas  d.  path. 

Histologic  menschlichcr  Ziihne       1901. 
(1."))  Willi \MS.     Dental  Caries.     Dnilnl  ('n.inios,  1897, 
Vol.   XXXIX. 


CHAPTER  XY 


THE  PATHOLOGY  OF    EROSION,  ATTRITION,  AND  ABRASION 


Erosion  may  be  defined  as  "a  progressive 
destruction  of  the  exposed  surfaces  of  teeth, 
])ro(iiieini;  cavities  tliat  are  peculiarly  dense 
and  polished,  and  in  the  majority  of  instances 
hypersensitive  on  receiving  tactile  impressions  " 
(5). 

The  causes  are  predisposing  and  exciting. 
Of  the  former  it  may  be  said  that,  in  all  pro- 
bability, certain  anatomical  relationships  of 
the  parts  are  concerned  in  its  production.  Thus 
if  the  enamel  and  dentine  do  not  meet  bout 
a  bout,  as  is  commonly  the  case,  but  fail  to 
toiicli  one  another,  a  minute  surface  of  dentine 
at  tlie  necks  of  the  teeth  is  denuded  of  its  usual 
covering,  and  may  in  certain  circumstances 
prove  to  be  the  seat  of  the  lesion.  Much  con- 
troversy has  arisen  over  the  nature  of  these 
circumstances,  being  mainly  due  to  the  con- 
fusion existing  in  the  minds  of  some  writers, 
who  regard  attrition  or  abrasion  of  the  teeth 
as  synonymous  ternis. 

It  has  generally  been  believed  that  there  is 
a  chemical  solution  of  the  three  hard  tissues 
at  their  point  of  junction,  caused  by  the  fermen- 
tation of  mucus  and  the  production  of  acid 
sodium  phosphate,  or  by  an  acid  fermentation 
occurring  in  the  material  located  in  the  area 
of  denudation,  through  the  action  of  the  mucus. 
Others,  inchuling  Miller,  per  contra,  consider 
it  to  be  entirely  mechanical  in  origin  (6);  while 
others  again  would  ascribe  it  to  both  these 
agencies. 

Kirk  has  found  acid  sodium  phosphate  in 
vhat  he  has  termed  hydroglyphic  (graphic) 
erosion.  He  considers  that  this  acid  is  produced 
during  diseases  of  sub-oxidation,  when,  as  a 
result  of  the  })erversion  of  metalxilism,  the  blood 
contains  more  carbonic  acid  than  is  normal. 
In  other  words,  gout  and  rheumatism  are  the 
nuiin  prcdisjiosing  causes.  He  would  suggest 
that  in  genei'al  erosion  lactic  acid  is  generated, 
and  is  the  solvent  of  the  enamel ;  that  in 
localized  conditions  acid  sodium  phosphate  or 
acid  calcium  piios]>ha(e  are  the  agents  involved 
(2). 

Black  is  of  the  opinion  that  it  seems  highly 
probable  that  the  .solution  of  the  question  will 
be  found  to  be  associated  with  "  some  systemic 
dyscrasia  ",  and  that  if  it  is  so,  "the  conditions 
leading  to  its  strict  localization  will  require 
explanation  "  (1). 


Erosion  nuist  be  clinically  distinguished  from 
abrasion  and  attrition.  If  the  definition  just 
given  be  accepted,  it  is  possible  to  describe  the 
maeroscopical  appearances  as  those  presented 
by  a  wedge-shaped  cut  or  gioove,  as  if  made  by 
a  file,  at  the  necks  of  the  teeth,  especially 
on  their  labial  or  buccal  aspects.  \'ery  occasion- 
ally, the  lingual  surfaces  of  the  crowns  of  the 
maxillary  canines  or  premolars  may  be  affected. 
The  cavities  are  smooth,  and  brightly  polished, 
and  at  first  possess  everted  edges,  a  relatively 
greater  portioTi  of  the  enamel  being  lost  than 
the  dentine.  These  cavities  may  be  coloured 
yellow,  brown,  black,  or  green,  in  various  shades. 
Hypersensitive  to  tactile  impressions,  but 
not  so  much  to  thermal,  chemical,  or  electrical 
stinudation.  they  may  rarely  be  (piite  insensi- 
tive. Pain  seems  to  be  associated  with  the 
earliest  and  not  the  latest  manifestation  of  their 
development. 

Histologically,  the  edges  of  the  cavity  exhibit 
the  presence  of  numerous  clefts  described  by 
Baume — minute  cracks  in  the  dentine,  on  the 
floor  of  the  cup-.shaped  depressions  that  go 
largely  to  form  the  component  parts  of  the 
eroded  surface.  The  enamel  margins,  at 
first  everted,  may  later  become  somewhat 
inverted,  but  they  never  simulate  those  due 
to  caries.  The  dentinal  tubules  that  proceed 
from  the  floor  of  the  cavity  become  obliterated — 
they  cannot  be  stained.  Adventitious  dentine, 
here  truly  a  ''dentine  of  repair",  is  deposited 
upon  the  surface  of  the  pulp  that  corresponds 
with  the  breach  of  surface.  It  roughly,  also, 
equals  this  in  amount.  It  is  constructed  of  an 
irregular  fine-tubed  material,  and  many  spaces 
frequently  cxi.st  similar  to  those  found  in  areolar 
adventitious  dentine  connected  with  lesions 
due  to  dental  caries. 

As  these  cavities  are  seen  on  labial  surfaces, 
the  use  of  porcelain  inlays  is  generally  indicated 
in  the  treatment  of  this  conclition. 

Attrition. — The  term  attrition  may  be  applied 
to  tiie  gradual  wearing  away  of  the  hard  parts 
of  teeth  through  the  physical  and  physiological 
agencies  of  mastication  of  food. 

A  certain  amount  of  faceting  of  the  occlusal 
surfaces  of  teeth  is  often  the  forerunner  of  a 
larger  attrition,  which  develops  in  the  course 
of  a  few  years.  The  teeth  of  those  whose  food 
is    hard    and    unrefined    often    suffer    severely 


304 


305 


from  this  physioloi^ical  masticatory  effort. 
Those  of  preliistoric  man  commonly  present 
bri^'htly  pohshed  flat  table-lands  of  dentine 
bordered  by  enamel,  whicli  have  become  dis- 
coloured by  age.  Tlie  niandilMilar  incisors  of 
modern  man  frequently  exhibit  a  narrow  strip 
of  brown  discoloration  ruruiini;  in  a  medio- 
distal  direction.  As  tiie  lesion  advances,  com- 
plete wearing  down  of  t  lie  crowns  may  sometimes 
be  seen. 

Tlie  enamel  that  lemains  at  the  edges  of  the 
surface  of  attrition  is  deeply  pigmented,  and 
tlie  dentine,  naturally  stained  tlirougliout  its 
entire  thickness,  presents  a  sharp  smooth 
surface  with  its  tubules  cut  tangentially  or 
transversely. 

Secondary  dentine,  as  distinguished  from 
adventitious  dentine,  is  fretiuently  deposited  in 
the  Jjulp  ;  it  is  generally  well  formed  and  consists 
<)f  a  fine  tube  formation  with  delicate  termi- 
nations, and  but  few  Ijranches.  ''  Transhicent 
zones  ''  may  l)e  found  in  tlie  ])rimarv  dentine. 

Abrasion  means  the  rapicl  wasting  and  de- 
struction of  enamel  and  dentine  l)y  friction 
set  up  by  the  presence  of  foreign  bodies  in  the 
mouth. 

In  complete  contradistinction  from  the  two 
jjreceding  conditions  is  abrasion,  in  which  the 
affected  surface  of  the  teeth  is  rough,  dull, 
flat,  extensive,  and  stained  yellow  or  brown. 


It    speedily    b(!Coines    carious,    atVordhig    ideal 
attachment  for  the  caries-producing  organisms. 

If  sections  are  examined  before  a  bacterial 
attack,  it  will  be  found  that  the  edges  of  the 
dentine  and  cementum  have  disappeared,  and 
the  extremities  of  the  dentinal  tidjules  are 
levelled  flat  w  ith  the  floor  of  the  abraded  sur- 
face, and  that  the  matrix  is  softened  and  can 
be  easily  stained  by  means  of  aniline  dyes. 
This  staining  can  be  effected  without  sectioning 
the  specimens. 

Micro-organLsms  can  be  demonstrated  lining 
the  floor  of  the  cavity. 

A.  H-S. 


BIBLIOGRAPHY 

(1)  Black.     Operative  Dentistry,  Vol.  I,  1908. 

(2)  BuBCHABD.      ,4     Text-book    oj    Dental    Pathology 

and  Therapeutics,   1912. 

(3)  CoLYER.     Dental  Surgery  ami  Pathology,  1910. 

(4)  Heide.     Erosion.     L'Odontologie,    1908. 

(5)  Hopewell-Smith.       The    Histology     and    Patho- 

Histology  of  the  Teeth  and  Associated  Parts,  1903. 
(b)  MiLLEB.      Experiments      and      Observations      on 
Erosion,     etc.      Dental      Cosmos,     1907,      Vol. 
XLIX,  pp.  1,  109,  225  and  677. 

(7)  Ottofy.    Oriental  Erosion.     Dental  Cosmos,  1905, 

Vol.  XLVII,  p.  71. 

(8)  Talbot.     Constitutional  Causes  of  Erosion,  Abra- 

sion,    and     Attrition.     Dental    Cosmos,     1905, 
Vol.  XLVII,   p.   47. 

(9)  Talbot.     Causes     of      Erosion     and     Abrasion, 

Dental  Cosmos,   1907,  Vol.  XLIX,  p.  122.'). 


CHAPTER  XVI 

DISEASES  OF  THE   DENTAL  PULP 


INTRODUCTORY 

It  can  be  but  a  small  matter  for  surprise 
that  the  pulp — the  most  important  part  of  a 
human  tooth,  from  every  pomt  of  view — should 
be  particularly  susceptible  and  predisposed  to 
disease,  when  it  is  remembered  that  its  ana- 
tomical situation  in  the  animal  economy  is  with- 
out a  like  or  equal  elsewhere,  in  consequence  of 
its  being  a  peripheral  organ,  implanted  m  a 
peripheral  environment,  subjected  to  perijjlieral 
structural  metamorphoses — through  the  unique 
vascular  and  nervous  mechanism  that  it 
possesses, — surrounded  by  dense,  unyielding 
walls,  and  rendered  easily  accessible  to  changes 
of  a  thermal,  bacteriological,  chemical,  and  elec- 
trical character. 

The  pulp  of  a  tooth — yea,  the  whole  tooth 
itself — is  a  peripheral  organ — in  much  the  same 
way,  properly  sj^eaking,  as  is  the  external  ear, — 
a  true  epidermal  structure,  placed  not  always 
in  the  oral  cavity.  The  ancestors  of  fishes  had 
dental  appendages,  closely  homologous  with 
dermal  appendages.  The  mouth  of  a  young 
dog-fish  displays  the  fact  that  the  oral  teeth 
are  the  homologues  but  not  the  analogues  of  the 
spines  on  its  skin  ;  the  saw-fish  {Pristis)  at  the 
present  day  possesses  certain  dental  ^\eapons 
of  offence  and  defence  on  its  rostrum  or  snout, 
in  addition  to  numerous  minute  teeth  of  a  less 
functional  type  on  the  surface  of  its  jaws.  In 
the  Gymnodonts  the  teeth  are  not  covered  by 
the  lips. 

It  is  not  difficult  to  conceive  that  Nature 
intended  the  teeth  to  last  throughout  the  life 
of  an  animal ;  even  perhaps  that  of  a  member 
of  the  highest  orders  of  Mammalia,  such  as  the 
Primates  and  Carnivora.  But  it  is  a  universal 
rule  that  the  older  the  creature  the  less  efficient 
is  its  masticatory  apparatus,  on  account  of  the 
impairment  or  the  lo.ss  of  its  functions,  or  the 
shedding  of  the  teeth  themselves.  That  this  is 
so,  is  further  demonstrated  by  the  fact  that  the 
osseous  foundations  of  the  teeth  of  man,  being 
peripherally  jjlaced  in  the  alveolar  processes  of 
the  jaws,  in  which  the  diploetic  bone  is,  at  its 
margins,  of  poor  construction  and  quality  and 
feebly  supplied  vith  blood,  are  anatomically 
and  histologically  deficient  in  those  properties 
that  tend  to  a  jiermanent  condition  of  life. 

A  third  remarkable  peculiarity  is  sho\^n  in 


the  microscopical  .structure  of  the  pulp.  There 
is  no  collateral  circulation  hi  its  blood  stream, 
which  might,  in  the  event  of  uijury,  attempt  to 
induce  a  restoration  of  the  vitality  of  the  affected 
parts ;  the  veins  are  valveless  and  non-collap- 
sible (10) :  no  lymphatic  system  is  present;  and 
the  apical  foramina  of  the  teeth,  which  transmit 
the  blood  vessels,  are  often  so  e.xceedingly  small 
in  adolescence  or  old  age,  that  it  seems  a  mar- 
vellous thing  that,  m  these  circumstances,  the 
pulp,  and  therefore  the  tooth,  is  kept  alive  at  all. 

In  addition,  the  arrangement  of  the  principal 
elements  of  its  nervous  system  is  such  as  to 
render  impossible  a  dkect  neurotic  control  over, 
or  influence  upon,  the  greater  portion  of  the 
tooth,  viz.  the  dentine.  Dentine  is  secondarily 
vitalized  by  lymph — a  protoplasmic  exudation 
from  the  pulp  itself, — while  enamel,  still  more 
remote,  is  entirely  outside  the  pale  of  nutrition. 

Finally,  it  is,  on  mature  reflection,  not  an 
extraordinary  thing  that  it  so  comparatively 
frequently,  as  the  march  of  so-called  civilization 
proceeds,  becomes  a  prey  to  the  attacks  made 
upon  it  by  the  changes  of  temperature  that  the 
oral  cavity  may  daily  experience,  a  temperature 
ranging  from  zero  to  40°  C. ;  a  locus  principii 
for  one  of  the  most  distressing  pains  that  man 
can  suffer ;  a  territory  constantly  invaded  by 
many  diseases  mainly  of  an  inflammatory 
character ;  and  an  organ  that,  more  commonly 
than  is  generally  supposed,  undergoes  retro- 
gressive changes. 

AETIOLOGY 

The  causes  of  diseases  of  the  pulp  may  be 
conveniently  considered  under  the  two  great 
classifications.  Predisposing  and  Exciting,  of 
which  the  former  may  be  cliiefly  congenital,  and 
the  latter  are  always  acquired  and  dependent 
somewhat  on  the  former.  The  exciting  causes 
may  be  further  sub-divided  into — • 

(a)  Tho.se  clue  to  exogenetic  disturbances. 
(h)  Those   due   to   endogenetic   disturbances. 

Regarding  these,  the  former  largely  predomi- 
nate in  point  of  view  of  frequency  of  occurrence, 
are  purely  local  in  origin,  and  are  influenced 
mainly  by  pathological  conditions  of  enamel  and 
dentine  induced  by  dental  caries  (bacteriological) 
or  thermal,  chemical,  electrical,  and  other  stimu- 


306, 


307 


lation  ;  give  rise  to  immediately  referred  symp- 
toms ;  and  yield  successfully  to  local  treat- 
ment. The  latter  are  only  occasionally  met 
with,  are  constitutional  in  origin,  and  depend 
largely  on  general  circulatory  variations  of  the 
blood  stream,  which  act  in  a  limited,  circum- 
scribed sphere. 

The  causes  may  be  summarized  as  follows— 

A. — Predisposing  : — ■ 

1.  General.  (a)   Physiological,   e.  g 

heredity,  sex,  age ;  and  (h)  Patho 
logical,  e.g.  marasmus,  long-con- 
tinued fevers,  etc. 

2.  Local.     Anatomical   individual- 

ities of  hard  and  soft  parts,  etc. 

B. — Exciting  : — 

1.  General.  Endogenetic  :  effects  of 

disease  of — (a)  Vascular  sys- 
tem, e.g.  anaemia,  chlorosis, 
etc.;  and  (6)  Nervous  system, 
e.  g.  neurasthenia,  etc. 

2.  Local.     Exogenetic.    [u]  Appar- 

ent :   Effects  of  dental  caries  ; 

and  (6)  Non-apparent :  Ther- 
mal, chemical,  and  electrical 
stimulations,  etc.  '' 

A. — Predisposing  Causes 

1.  General. — While  the  relationship  be-  ^- 
tween  cause  and  effect  is  fairly  well  under-  ', 

stood,  it  is  impossible  to  ascertain  very 
strictly  the  nature  of  the  complex  jarocesses 
that  may  develop  in  pathology.  Especially 
is  this  so  with  regard  to  those  cases  associ- 
ated w  ith  heredity.  The  effects  of  parent- 
age on  progeny  are  so  difficult  to  follow, 
and  involve  such  large  issues,  that  general- 
izations only  can  properly  be  made  as 
to  plausible  beliefs  respecting  the  question. 
It  is  true  that  heredity  can  be  reduced  by  some 
to  a  mere  porism ;  it  is  also  true  that  heredity 
has  a  control  over  circumstances  that  markedly 
influence  the  determination  m  the  shapes,  sizes. 
and  j)ositions  of  the  crowns  and  roots  of  teeth, 
and  that  the  consequences  of  disease  are  fre- 
quently handed  down  from  father  to  son.  But 
probably  the  pulp  suffers  in  this  manner  very 
little,  although  there  may  be,  at  times,  some 
recondite  transmission  of  susceptibility  to  the 
onset  of  morbid  conditions  existing  on  its 
part. 

Regarding  sex,  one  cannot  recognize  with 
facUity  the  differences  either  macroscopically 
or  microscopically  between  male  and  female 
teeth.  In  a  less  degree  than  the  hard  parts,  it 
may,  however,  be  assumed  that  the  pulps  of 
the  teeth  of  the  two  sexes  do  really  differ  (11). 
There  is  some  support  for  the  theory  of  this  differ- 


ence when  the  morphology  of  tlie  dental  tissues 
is  considered ;  and  it  would  seem  as  if  there 
were  some  good  grounds  for  the  belief  that 
the  fact  of  vascular  alterations  taking  place  in 
women  at  definitely-recurring  intervals  of  time 
would  constitute  a  fundamental  difference  be- 
tween the  two.  There  is  a  widespread  belief  in 
Great  Britain  that  in  parturient  women  a  loss 
of  a  tooth  coincides  with  the  bii'th  of  each 
child. 

Age  plays  a  somewhat  more  prominent  part 
in  the  determination  of  pulp  diseases  than  the 
factors  just  mentioned.  There  can  be  no  deny- 
ing that,  as  time  goes  on,  acute  inflammation 


"t."^ 
.¥■ 


Fig.  399. — Calcareous  degeneration  of  deciduous  molar. 
D,  Dentine ;  P,  Pulp,      x  45. 

j  becomes  rarer,  and  odontalgia,  its  main  symptom, 
1  less  frequent,  whilst  degenerations  of  various 
kinds  become  more  and  more  common.  These 
conditions  are  not  necessarily  connected  with 
the  actual  number  of  years  of  the  individual's 
life,  but  with  the  age  of  the  tooth  and  its  pulp. 
Children's  deciduous  teeth  often  show  his- 
tological evidences  of  calcareous  infiltration, 
fibroid  degeneration,  and  other  morbid  condi- 
tions coincident  with,  and  incidental  to,  old  age. 
Predisposition  to  disease  on  the  part  of  the 
l^ulp  is  dependent  on  the  connections  existing 
between  it  and  other  parts  of  the  body,  as 
evidenced  by  the  vascular  and,  in  a  limited 
degree,  by  the  nervous  system.  The  general 
disorder  of  these  systems  at  or  about  the  age 
of  puberty  in  both  boys  and  girls  renders  the 
pulp  favourable  to  organic  disease.  In  women 
at  the  cata  menial  periods  and  the  menopause 
I  the   same   thing   happens  :  repeated  elevations 


308 


of  the  blood  pressure  in  its  substance,  succeeded 
by  frequent  falls,  are  aetiological  factors  that 
cannot  possibly  be  ignored. 

Certain  chronic  diseases  in  which  grave  evi- 
dences of  katabolic  metabolism  occur,  in  addi- 
tion to  general  disturbances  of  metabolism 
originating  in  infections  or  auto-intoxications 
accompanied  or  iniaccompanied  by  fever,  may 
leave  their  marks  on  the  life  histories  of  the 
pulp  and  dental  tissues.  Degenerations,  such 
as  fatty  or  albuminous,  may  arise  in  this  organ 
during  the  course  of  acute  general  pyrexial  or 


Fig.  400. — Fibroid  degeneration  of  tlie  pulp  in  a 

deciduous  tooth. 

D,  Dentine ;  P,  Pulp.      X  45. 

apyrexial  maladies  :  degenerations  of  a  fibroid 
type  may  follow  in  the  train  of  anaemia, 
chlorosis,  leukaemia  and  the  like ;  and  gout, 
rheumatLsm  and  allied  conditions  become  a.sso- 
ciated  with  nodular  deposits  of  calcified  material 
within  its  substance. 

It  may  be  truly  remarked  that  tlie  general 
health  of  an  individual  is  as  important  for  the 
welfare  of  the  teeth,  and  their  sockets,  as  it  is 
necessary  for  the  welfare  of  the  heart,  the  in- 
testines, the  lungs,  the  kidneys,  and  the  liver. 
The  teeth  suffer  as  a  result  of  rickets  and 
syphOLs,  and  of  the  exanthematous  fevers,  in  the 
early  stages  of  their  growth  and  development ; 


and,    later,  chlorosis,   anaemia,   long-continued 

fevers,     certam     neurotic     influences,     etc.     A 

vicious    circle    may    absolutely    be    established 

by  the  anaemic  conditions   of  the   immediate 

osseous  environment  of  a  tooth,  giving  rise  to 

atrophy  and  symptoms  of  dLsease  of  the  bone 

and    periosteum,    and    setting    up,    if    infected 

with  jiyogenic  bacteria,  a  pyorrhoea  alveolaris, 

and  forms  of  oral  sepsis,  \\'hich,  in  their  turn, 

are    lielieved    by    some    to    induce,  at  times, 

secondary  anaemia  or  be  associated  with  it. 

In  marasmus,  which  is  a  pathological   lesion 

when  occurring  in   the  young,  the   pulp  may 

undergo  retrogressive  changes  like  other  organs ; 

such   are   the  epidermis,   which   becomes    dry 

and   cracked   and   rapidly   desquamates ;    the 

blood   vessels    and    epithelial    linings    of    the 

alveoli  of  the  lungs,  as   well   as   their  elastic 

fibres:  the  lamellae  of  bone,  which  disappear; 

etc.     Finally,  in  general  cachexia  the  chemical 

composition    of    the    blood    is    changed    and 

may    jjioduce   thrombosis,    multiple  capUlary 

haemorrliages.    and    even    go    so    far    as    to 

diminish  the  volume  and  weight  of  the  pulp 

itself. 

2.  Local. — It  has  already  been  hinted  that 
the  pulp  differs  in  several  exceptional  ways 
from  any  other  organ  of  the  body.  These 
are  principally  anatomical,  as  already  noted ; 
and  the  influence  of  these  curious  structural 
features  on  the  general  well-being  of  the 
pulp  leads  the  writer  to  the  conclusion  that 
it  is  rare  to  find  a  healthy  normal  pulp  in 
a  tooth  of  a  European,  Asiatic,  or  American, 
after  the  age  of  twenty-five  years.  The  vast 
majority  are  degenerating,  or  have  already 
undergone  retrogressive  metamorphoses.  It 
must  be  so ;  for  if  the  apices  of  the  roots 
of  teeth  after  that  age  be  examined,  it  will 
at  once  be  obvious  that  the  foramina  are  so 
diminutive  that  it  is  impossible  to  insert  a 
fine  needle-point  through  their  apertures  into 
the  root-canal.  The  openings  will  certainly 
not  admit  a  horse's  or  a  camel's  hair; 
measured,  they  may  only  possess  a  diameter 
of  5  fi. 

In  many — almost  the  majority — of  the 
specimens  examined,  the  apical  foramina  are 
macroscopically  invisible,  whUe  even  a  lens,  in 
numerous  instances,  fails  to  detect  traces  of 
their  presence.  And  this  is  a  universal  fact ; 
thus,  in  a  miscellaneous  collection  of  permanent 
teeth  of  adults,  rich  and  poor  alike,  sent  to  the 
WTiter  from  India  for  the  special  purpose,  no  less 
than  24  per  cent  had  closed  and  completely 
obliterated  foramina. 

It  is  quite  inconceivable  that  the  natural 
nutrition  of  the  soft  parts  in  the  interiors  of 
teeth  can  be  projjerly  carried  on,  if  the  afferent 
and  efferent  vessels  are  restricted  to  so  limited 
an  area  of  ingress  and  egress.     After  the  apical 


309 


foramina  have  become  closed, '  the  blood  supply,  ] 
hitherto  abundant,  or  at  all  events  adequate,  I 
becomes  sooner  or  later  insufficient,  and  there-  1 
fore  inefficient,  and  the  first  stages  of  degenera-  j 
tion  and  disease  begin. 

Many  children's  teeth  show  these  initial 
changes  ;  different  teeth  from  the  same  mouth 
also  exhibit  them. 

It  would  be  interestmg  to  attempt  to  ascertain 
why  the  foramina  become  contracted  and  oc- 
cluded as  years  pass  by.  It  may  be  suggested 
in  the  absence  of  definite  clinical  and  laboratory 
data,  that  the  growth  and  consolidation  of  the 
osseous  frame\\ork  of  the  jaws  may  press  upon 
the  "  formative  rings  "  of  growing  dental  tissue 
— as  a  result  of  the  shortening  of  the  jaws  and 
the  absence  of  diminution  in  the  standardiza- 
tion of  the  size  of  the  teeth — and  gradually  bring 
about  tliis  constriction  and  actual  occlusion  of 
the  orifices.  Added  to  this,  there  are  also, 
most  commonly,  areas  of  pathological  cementum 
deposited  on  the  surface  of  the  roots,  a  fact  that 
might  itself  be  a  contributing  cause.  Anotlier 
sign  of  degeneracy,  too,  is  seen  on  examining 
the  portions  of  the  teeth  by  transmitted  light ; 
a  great  number  reveal  a  tendency  to  a  trans- 
parency of  the  tissues. 

Among  local  predisposing  causes  of  pulp 
disease  may  be  mentioned  the  presence  in  the 
enamel  and  dentine  of  one  or  more  metallic 
or  porcelain  fillings,  whether  pure  gold,  or  mi.x- 
tures  of  tm,  copper,  etc.,  or  the  lute  of  an  inlay 
placed  in  situ  as  obturations  for  carious  cavities. 
If  the  pulp  has  escaped  the  effects  of  the  caries, 
and  is  in  a  more  or  less  physiologically  responsive 
condition,  it  has  a  propensity  to  be  secondarily 
affected  by  the  presence  in  its  neighbourliood 
of  a  mechanical,  inert,  dead  mass,  and  its  blood- 
pressure  to  be  subject,  at  times,  to  certam 
exacerbations  and  declines  in  varymg  circum- 
stances. A  tooth  containing  a  filling  is  almost 
certain  to  have  a  degenerate  or  degenerating 
pulp  ! 

B. — Exciting  Causes 

1.  General. — These — endogenetic  in  origin — 
are  necessarily  associated  with  disturbances 
of  the  vascular  and  nervous  systems.  Tlius, 
anaemia,  chlorosis,  or  other  conditions  due 
to  alteration  in  the  chemical  constituents  of 
the  blood,  which  may  or  may  not  lead  to 
diseases  of  the  vessel  walls,  or  elevation  or 
depression   of  the   blood-pressure   in  the   pulp, 

'  Closiire  of  tlie  apical  foramina  occurs  approximately 
as  follows: — Maxilla  — first  incisor,  11th  year;  second 
incisor,  Uth  year;  canine,  13th  year;  first  premolar, 
12th  year;  second  premolar,  12th  year;  first  molar, 
12th  year;  second  molar,  l.ith  year;  third  molar,  19th 
year.  Mandible — first  incisor,  10th  year;  second 
incisor,  11th  year;  canine,  13th  year;  first  premolar, 
12th  year;  second  premolar,  12th  year;  first  molar, 
11th  year;  second  molar,  Kith  year;  third  molar,  21st 
year. 


belong  to  the  first  group ;  while  neurasthenia, 
hysteria,  or  repeated  undue  excitability  of  the 
nervous  system  reacting  locally,  belong  to  the 
second. 

After  due  consideration  of  the  peculiar  ana- 
tomical conditions  of  the  parts  as  already  re- 
counted, it  is  not  surprising  that  lesions  arising 
from  variations  in  the  blood  stream  or  in  the 
blood-pressure  itself  should  be  fairly  common. 
So  much  is  this  the  case,  that  it  is  probably  true 
to  assert  that,  while  teeth  are  very  frequently 
the  victims  of  dental  caries,  they  may  also 
equally  and  simultaneously  be  subjected  to 
internal  retrogressive  metamorphoses  induced 
by  a  lowered  or  altered  physiological  resistance, 
or  lack  of  it,  on  tlie  part  of  the  pulp,  through 
the  unusual  characteristics  of  its  blood  supply. 
This  does  not  always  apply  to  the  normal  indi- 
vidual, but  applies  more  especially  to  those 
who  suffer  from  disturbances  of  the  circulatory 
system. 

Many  persons  undergo  a  certain  transitory 
discomfort  brought  about  by  hyperaemia  of  the 
pulp.  For  some  reason  the  ves.sels  become 
vicariously  overfilled  and  undergo  hypostatic 
congestion,  which  presently  disappears  when 
j  the  cause  is  removed  or  when  there  is  an  effective 
outlet  provided  for  an  uninterrupted  flow.  If, 
however,  the  intra-dental  pressure  is  so  severe, 
and  so  sudden,  as  to  prevent  the  occurrence 
of  a  rapid  and  permanent  relief,  then  the  tissues 
degenerate  and  perhaps  die,  as  they  are  unable, 
on  account  of  their  dentinal  envelopment,  to 
accommodate  tliemselves  to  their  engorged 
state.  Ferdinand  Tiinzer  (17)  has  recently  em- 
phasized this  point. 

The    introduction    of    metallic    fillings    and 
cement  floorings  into  carious  cavities,  to  which 
j  reference  has  already  been  made,  is  sometimes 
followed  by  local  pain,  and  the  work  of  obtu- 
ration Ls  credited  by  the  uninformed  with  being 
j  the  cause  of  the  odontalgia,  while  it  is  often  due 
I  merely  to    either  reflex   nervous    irritation   or 
a  rise  in  the  local  blood-pressure. 

It  is  thus  clear  that  temporary  engorgement 
j  of   the   vessels   of   the   pulp   tends   to   produce 
odontalgia  of  varyuig  degrees  of  severity  ;  but 
if  this  congestion  is  still  continued,  death  of  the 
parts  ensues,  \^ith  complete  cessation  of  pain. 
I  This  may  be  occasioned,  (a)  slowly,  when  the 
tis.sues  pass  through  the  various  stages  of  fibroid 
degeneration,  or  (&)  rapidly,  when  moist  gan- 
grene supervenes  as  a  result  of  thrombosis  and 
!  arterio -sclerosis,    and    sudden    death  en  masse 
takes  place.     Fortiuiately,  gangrene  as  a  perma- 
nent   termination   of   thrombosis   Ls   a   contin- 
gency of  comparatively  infrequent   occurrence 
from  a  clmical  point  of  view.     It  is  believed 
that  a  slight  rise  of  blood -pressure  produces  no 
symptoms  of  neuralgia,  though  it  can  be  readily 
I  conceded  that  pain  from  other  areas  may  be 


310 


reflected  to  a  tooth  that  is  sound,  but  whose 
pulp  is  somewhat  liyperaemic. 

Exaininatiou  of  sections  showing  these 
vascuhir  lesions  under  the  microscope  displays 
the  engorgement  of  the  capillaries  and  small 
veins  that  are  distributed  to  the  peripheral 
parts  of  the  pulp,  and  particularly  to  the  coronal 
region.  The  corpuscles  and  blood  platelets 
are  appreciably  altered  in  shape  and  size — due, 
no  doubt,  very  largely  to  certam  haemic  changes, 
which  favour  coagulation ;  they  may  partially 
or  completely  fill  the  lumina  of  the  vessels  and 
are  sometimes  arranged  in  rouleaux  ;  frequently 


Fig.  401. — Longitiulmal  snliiMi  of  pulp  Kliowing  tlirom- 

bosis  of  capillaries  and  other  vascular  lesions. 

D,  Dentine.      X  45. 

they  have  escaped  into  the  surrounding  tissues 
as  a  result  of  the  rupture  of  the  vessel  walls. 
Small  arterial  haemorrhages  are  often  seen,  at 
times  among  the  odontoblasts,  at  times  in  the 
basal  layer  of  VVeU,  and  at  times  in  the  sub.stance 
of  the  pulp  it.self.  The  haemorrhagic  infarcts 
may  vary  in  composition  from  a  punctiform 
collection  of  a  dozen  or  more  corpuscles  to  many 
hundreds  clustered  together  to  form  a  large 
mass.  The  endothelium  of  the  ttinica  intima 
of  these  arteries  and  capillaries  is  altered,  and 
the  nuclei  of  its  cells  are  indi.stinguLshable.  The 
larger  arteries  and  larger  veins  are  empty,  and 
hyaline  areas  of  degenerated  material  in  many 
places  extend  across  them,  and  as  they  become 


smaller,  entirely  occlude  their  lumina.  The 
arteries  and  veins  have  lost  their  distinguishing 
coats,  both  having  thinner  walls  than  usual, 
showmg  a  truly  hypoplasic  or  hyaline  degenera- 
tive change. 

The  odontoblasts  are  enormously  multiplied, 
are    vacuolated,    are    flattened    laterally,    and 
possess    planiform   nuclei ;    they  are  colligated 
into  sheaves.      The  basal  layer  of  Weil — free  in 
normal  conditions — is  rich   in  small  cells  with 
large  round   nuclei,   and  its   fibrous   parts  are 
prominent.     The  cells  of  the  pulp  proper  possess 
nuclei  that  are  degenerate  in  shape  and  small 
in  size ;    their  branches  are  well  marked  and 
increased  in  number.     The  nerve  bundles  are 
degenerating.     Organization  of  thrombi  pro- 
ceeds in   places,   leaving  only  a  thin  fibrous 
ccird  or  hyalme  mass  coherent  with  the  walls 
(ir  completely  filling  the  lumina  of  the  vessels. 
Al^sence  of  a  collateral  circulation  predisposes 
t(i  the  onset    of   thrombosis.     Any   increased 
\  olume  of  fluid  (blood)  must  be  compensated 
by  a  corresponding  outpouring,  as  there  cannot 
be  an  adequate  displacement  of  the  surround- 
ing parts  to  afford  the  room  required. 

A  thrombus  may  be  the  cause  or  the  result 
of  arteritis  or  jjlilebitis ;  it  may  be  due  to 
chemical  changes  in  the  blood  itself,  or  to 
lesions  in  the  vessel  walls,  as  in  degeneration. 
( )sler  (13)  has  observed  that  durmg  thrombus 
Inrmation  the  blood  platelets  described  by 
Hizzozero  (1),  and  Eberth  and  Schimmelbusch 
(7),  are  the  first  of  all  the  blood  elements  to 
accumulate  upon  the  vessel  walls  during  coagu- 
lation, and  that  the  filaments  of  fibrin  spread 
principally  from  these  plate  masses.  They 
undergo  viscous  metamorphoses  and  also 
conglutination,  as  explained  by  Thoma.  The 
thrombi  in  the  pulp  consist  of  corpuscles, 
platelets,  fibrin  filaments,  and  a  colourless 
semi-transparent  homogeneous  material.  They 
are  of  the  hyaline  variety,  and  are  non- 
infected. 

Thus  it  ^vould  appear  that  in  the  dental  pulp 
chemical  haemic  changes,  plus  the  unusual 
arrangement  of  the  termmal  vessels,  assisted  by 
the  vis  a  tergo,  which  naturally  leads  to  a  certain 
retardation  of  the  flow,  and  therefore — as  first 
pointed  out  by  Virchow — coagulation,  are  the 
originators  of  atrophic  influences.  Marantic, 
anaemic,  and  debilitated  conditions,  which  often 
form  the  sequelae  of  long-continued  and  en- 
feebling diseases,  have  the  same  or  similar 
efl'ects  on  the  vascular  system.  Other  diseases 
of  the  vessel  walls  occur  in  the  pulp,  such  as 
chronic  arteritis,  atheroma  or  endarteritis, 
phlebitis,  and  varicosity  of  the  veins.  Un- 
fortunately they  are  undiagnosable,  and  all 
terminate  in  degenerative  clianges  or  inflam- 
mation and  death  of  the  tissue. 

Regarding  the  effects  produced  by  diseases 
of  the  nervous  system,  little  need  be  said.     In 


311 


so  far  as  the  trophic  influence  of  the  vascular 
mechanism  Ls  a  permanent,  predominant,  de- 
termining, and  important  factor,  by  so  much  is 
the  ciiculatory  system  affected ;  the  two  are 
interdependent.  In  short,  the  diseases  of  the 
pulp  depend  upon  the  impaired  vitality  of  the 
body  generally,  and  the  circle  is  completed  by 
the  diseases  of  the  former  producing  at  times 
various  forms  of  dyscrasia  in  the  latter. 

2.  Local — 

(a)  Apparent- — Effects  of  Dental  Caries. — The 
action  of  micro-organisms  on  Nasmyth's  mem- 
brane and  the  enamel — no  matter  whether  they 
be  liquefying  or  non-liquefying — produces  prob- 
ably no  direct  effect  on  the  pulp ;  there  are  no 
evidences  to  show  it.  When  the  outer  zone  of 
dentine  is  reached,  however,  and  the  micro- 
organisms are  able  easily  to  penetrate  its  depth, 
on  account  of  its  tubularity,  changes  at  once 
originate. 

Tlie  first  phases  of  the  plienomena  associated 
with  breach  of  surface  are  concomitant  with 
cellular  activity ;  and  a  barrier  to  the  bacterial 
incursions,  composed  of  adventitious  dentine 
conveniently  classified  as  areolar,  cellular,  fibril- 
lar, hyaline,  and  laminar  (10),  is  thrown  up  on 
the  pulp  side  as  a  rampart.  But  the  con- 
structive do  not  proceed  pari  passu  witli  the 


less  rapidly  accomplished,  and  an  entrance  to 
the  pulp  cavity  is  effected,  in  spite  of  the  lowered 
physiological    resistance,    and    in    spite    of   the 


Af.' 


mm^ 


L 


Fio.  402. — Blood  \essols  iii  liyperaoiuia  of  the  pulp.      X    250. 

destructive  transformations  ;  for  the  cells  appear 
to  lose  their  power  of  forming  dentine  and 
offering  physiological  resistance  to  the  demolition 
of  enamel  and  dentme,  wliich  becomes  more  or 


Fio.  403. — Areolar  adventitious  dentine.      X   180. 

limited  area  occupied  by  the  adventitious 
dentine.  Thus  it  is  never  observed  that  the 
soft  tissues  become  enth-ely  obliterated,  but 
only  partially  so  at  the  spot  oppo- 
site to  the  breach  of  surface.  Com- 
plete calcification  of  the  jiulp  can  and 
does  take  place  in  entirely  dLssimilar 
circumstances. 

The  appearance  of  hyperaemic  foci 
is  tlie  very  next  indication  that  the 
pulp  is  becoming  affected  by  disease. 
There  is  a  bacteriological  irritation  of 
the  protoplasm  in  the  dentinal  tubes. 
Long  before  the  micro-organisms  reach 
the  innermost  portion  of  tlie  dentine 
their  toxic  products  liave  passed  on- 
wards in  the  vanguard  of  the  advancing 
destructive  host.  At  first  this  uivasion 
is  slight,  because  the  diameters  of  the 
tubes  and  their  branches  are  so  minute 
(about  2'5  fi.  to  immeasurability)  that 
only  the  smallest  of  micrococci  can 
effect  an  entrance.  As,  however,  the 
matrix  becomes  peptonized  and  re- 
moved, and  the  tubes  become  larger 
in  diameter  at  their  distal  extremities, 
mixed  infections  of  bacteria  occur, 
greater  numbers  gather  together,  and 
the  individual  liquefaction  foci  are 
increased  in  size.  By  tliis  time,  in  the 
majority  of  cases,  pain  has  been  ex- 
perienced, indicating  that  hvperaemia 
has  begun.  The  immediate  effect  of  the  invasion 
of  bacteria,  therefore,  is  a  toxic  infection  of  tlie 
pulp,  which  endeavours  to  make  an  immediate 
effort  to  repel  the  attacks  of  the  enemy. 


312 


Wlien  bacteria  invade  the  cementum,  as  some- 
times happens  in  the  roots  of  maxillary  permanent 
molars,  through  exposure  due  to  loss  of  bone  on 
the  internal  aspect  of  the  alveolar  socket,  they 
penetrate  the  tissues  by  means  of  the  canals 
that  contain  Sharpey's  fibres.  This  invasion, 
unlike  that  via  the  coronal  surface,  is  unaccom- 
panied by  a  deposition  of  adventitious  dentine, 
probably  because  it  occurs  later  in  life,  and  the 
cells  of  the  pulp  are,  therefore,  unable  to  lay 
do^m  fresh  dentine  on  the  pulp  surface. 

(b)  No7i-apparent — Effects  of  Thermal,  Chemi- 
cal, and  other  Stimulations. — The  variations  of 
temperature  that  the  mouth  may  undergo  during 
the  course  of  a  fashionable  English  meal,  in  which 
scalding  hot  fluids  are  succeeded  shortly 
by  icy  cold  confections,  exercise  a  deleteri- 
ous influence  on  the  pulp.  Hence,  while 
normally  the  pulps  are  proljably  maintained 
at  a  temperature  a  fraction  of  a  degree 
higher  than  blood  lieat,  the  result  of  its 
elevation  or  lowering  is  to  act  partly  on  the 
arterial  supply  and  partly  on  the  nervous 
system — heat,  of  course,  producing  vaso- 
dilatation and  a  tendency  to  hyperaemia 
and  pam ;  and  cold,  producing  vaso-con- 
striction  and  anaemia  and  al.so  pain.  Pulps 
constantly  liable  to  experience  these 
thermal  vicissitudes  cannot  but  be  rendered 
amenable  to  the  attack  of  disease  or 
degeneration,  slow  at  first  but  nevertheless 
sure.  The  nerve  bundles  become  easily 
sensible  to  exogenetic  irritation  and  lose 
their  tonic  authority  over  the  blood  vessels  ; 
vaso-dilative  and  vaso-constrictive  influ- 
ences, alternating  in  a  struggle  for  supre- 
macy, lead  in  the  end — which  may  be  soon 
— to  the  loss  of  the  normal  physiological 
equilibrium  of  the  parts,  and,  as  a  result 
of  one  being  overcome,  the  pulp  suffers 
irreparably,  and  the  way  is  paved  for  one 
or  other  of  the  exciting  causes. 

The  effects  of  chemical  stimulation  of  the 
hard  parts  in  an  apparently  sound  tooth  are 
probably  negative.  The  combined  application 
of  lukewarm  alkalies,  and  natural  and  mineral 
acids,  cannot,  per  se,  unless  Nasmyth's  mem- 
brane and  the  enamel  have  been  removed,  prove 
inimical  to  the  pulp.  The  acids  only  act  as 
solvents — as,  for  instance,  in  the  case  of  1% 
lactic  acid — by  first  destroying  the  enamel 
and  then  the  dentine  :  while  lactic  acid,  1  in 
1000  parts,  probably  has  no  ill  effect  what- 
ever, it  is  likely  that  malic  and  citric  acids 
in  weak  solutions  continuously  applied  have. 
It  is  evident  that  in  this  instance,  however, 
the  pulp  would  repair  itself  so  thoroughly, 
that  its  whole  coronal  or  cervical  portions 
might  become  calcified  by  successive  deposi- 
tions of  adventitious  dentine  on  its  surface, 
and  remain    to    the   end   a   normal   organ,   as 


far  as  its  radicular  regions  are  concerned.  The 
liability  to  an  attack  of  disease,  therefore, 
as  the  result  of  chemical  .stimulation,  is  perhaps 
reduced  to  a  minimum.  This  is,  however, 
different  in  the  case  of  a  carious  tooth ;  the 
pathological  conditions  set  up  by  the  repeated 
accidental  or  purposeful  application  of  acids 
to  a  carious  cavity  \\ould  ultimately  end  in  the 
death  of  the  pulp. 

The  above  remarks  apply  also  to  voltaic 
irritation.  A  tooth  that  does  not  contain  a 
metallic  substance  on  its  surface  is  not  subjected 
to  retrogressive  changes,  and  the  pulp  will  not 
respond  by  exhibiting  a  nerve-storm  on  the 
application  of  such  a  current. 


Fig.  404. — Hyperaemia  of  the  pulp. 
D,  Dentine ;  P,  Piilp.      X  45. 

HYPERAEMIA 

WliUe  it  has  been  already  claimed  that  on 
account  of  its  anatomical  surroundings  the  pulp 
occupies  a  unique  position  in  the  human 
economy,  it  may  be  predicated  at  once  that 
pathologically  no  such  distinction  can  be 
made.  Pathological  events  and  phenomena 
are  observed  here  occurring  in  precisely  the 
same  way  as  in  other  soft  organs,  with  the 
exception  that  they  are  modified  by  the  en- 
vironmental factors  previously  enumerated. 
Essentially  the  morbid  processes  are  identical, 
their  causes  similar,  their  courses  analo- 
gous, their  results  alike,  and  the  variations 
due  to  tlieir  anatomical  peculiarities  of  little 
con.sequence,  though  clinically  important. 

The  nutritional  well-being  of  the  pulp — 
a  normal  condition — depends  upon  the  proper 


313 


regulation  of  its  blood  supply,  which  is  governed 
by  the  influence  of  the  vasomotor  nerves  of 
the  unstriped  muscle  fibres  in  the  walls  of  the 
arteries,  the  normal  elastic  tissue  in  the  tunica 
media  of  these  vessels  maintaining  simul- 
taneously the  necessary  "  tone  ".  When  the 
usual  amount  of  blood  exceeds  this  physio- 
logical limitation,  pathological  hyperaemia — a 
frequent  forerunner  of  inflammatory  or  de- 
generative changes — Ls  induced,  and  is  called 
arterial,  active,  or  congestive  hyperaemia. 

Arterial  hyperaemia  may  be  brought  about 
by  any  condition  that  either  paralyses  the 
vaso-constrictor  nerves,  or  stimulates  the 
vaso-dilator  nerves,  or  \\eakens  the  tunica 
media,  or  removes  the  extra-vascular  pres- 
sure. In  dental  caries,  «hen  a  sufficiently 
large  area  of  dentine  has  been  exposed, 
various  forms  of  irritation  may  set  up  a 
localized  regional  hyperaemia,  which  is 
known  as  coronal,  cervical,  or  cornual,  ac- 
cording to  the  parts  of  the  pulp  affected ; 
such  as  the  chemical  or  bio-chemical  pro- 
ducts of  decomposition  of  liquid  or  soft 
food,  vitiated  oral  secretions,  thermal 
changes  in  the  mouth,  and  drugs  medicin- 
ally or  artificially  applied  for  curative  or 
experimental  purposes.  Cold  paralyses  the 
vaso-constrictors,  heat  the  vaso-dUators, 
while  the  protoplasmic  irritation  of  the 
dentine  (via  the  tubules)  caused  by  the 
products  of  bacteria  and  the  use  of  chemical 
reagents  probably  weakens  the  vessel  walls. 

Venous  hyperaemia,  or  passive  conges- 
tion, occurs  much  more  frequently  than 
arterial  hyperaemia,  and  is  due  to  an 
abnormal  obstruction  to  the  outflow  of 
blood  from  the  veins  of  the  jKilp.  depending 
upon  local  conditions.  The  seat  of  the 
obstruction  is  at  the  apical  portion  of  the 
roots  of  the  teeth,  where  the  mechanical 
pressure  of  hard  dentinal  walls,  combined 
with  the  absence  of  a  collateral  circulation, 
causes  its  development  to  the  fullest 
degree. 

The  microscopical  changes  iii  the  pulp 
due  to  venous  congestion  need  not  now  be 
detailed ;  they  have  been  fully  described 
elsewhere  (11).  Suffice  it  to  say  that  here, 
as  in  other  soft  parts,  there  is  a  capillary 
and  venous  dilatation,  the  pulp  becomes  deeply 
reddened,  the  axial  and  peripheral  blood  cur- 
rents in  the  veins  become  confused,  the  red 
corpuscles  are  densely  crowded  together,  and 
stasis  (the  cessation  of  flow  of  the  blood  stream) 
and  diapedesis  (the  emigration  of  corpuscles 
through  the  vessel  walls)  supervene.  The 
dUatation  of  the  veins  and  capillaries  arises 
from  the  loss  of  balance  of  haemodynamic  pres- 
sure, caused  by  the  les.sened  resistance  of  the 
blood  stream  to  friction,   through  its  slowing 


down.  A  transudation  of  serum  is  favoured 
by  the  intra-vascular  pressure  ;  and  more  or  less 
oedematous  conditions  soon  ensue,  because  of 
the  absence  of  lymphatics  from  the  pulp.  If 
the  conditions  remain  unrelieved,  acute  inflam- 
mation takes  place,  and  deatli  and  moist 
gangrene  conclude  the  attack. 

Clinically,  the  symptoms  are  those  of  odontal- 
gia coming  on  as  a  direct  result  of  stimulation 
by  cold.  The  pain  may  cease  at  once  on  removal 
of  the  cause,  or  persist  for  some  hours  and 
assume  a  neuralgic  character. 


FK! 


C, 


.   40.5. — Vertical    .st'ctioii   of  carious  tnotli  with   pulp 

(71  situ. 
Cavity;    CD,  Carious  dentine;   P,   Pulp  which  is  very 
hyperaemic.      X  45. 

INFLAMMATION 

Inflammation  is  the  com])lcx  local  reaction 
of  tlie  tissues  to  injuries  and  lesions  of  various 
kinds.  "  In  recent  years  it  has  become  more 
and  more  evident  that  the  only  theory  that 
allows  the  full  meaning  of  inflammation  to  be 
grasped  is  the  broad  biological  conception  which 
recognizes  in  inflammation  an  adaptive,  pro- 
tective, and  reparative  tendency  common  to 
the  reactions  to  injury  among  all  animals." 
Hektoen  and  Riesman  (9). 

To  Cohnheim  (tj)  and  Metchnikoft"  (12)  belong 


314 


the  credit  for  a  great  deal  of  the  early  and  late 
knowledge  of  tliis  subject. 

"  Inflammation  brings  mto  operation  a  num- 
ber of  factors  to  counteract  harmful  agents, 
protect  the  organism  at  large,  and  effect  healing. 
The  common  mode  of  origin,  the  similarity  of 
the  changes  (though  combmed  in  difl^erent 
proportions),  and  the  evident  tendency  of  the 
inflammatory  processes  to  protect  and  repair, 
justify  fully  the  teaching  that  inflammation  is 
essentially  an  adaptive,  protective,  and  repara- 
tive process,  a  means  of  self-preservation.  Yet 
it  must  not  be  forgotten  that  the  mechanism  of 
defence  and  preservation  is  far  from  perfect : 
the  exudate  may  possess  but  little  bactericidal 
power  ;  the  j)hagocytes  may  be  po\\erless  or  the 
bacteria  may  multiply  freely  ^\  ithin  them ; 
extensive  destruction  of  tissue  may  occur  before 
the  virulence  of  the  bacteria  is  neutralized ;  the 
fixed  cells  may  form  imj)erfect  material  for 
repair  or  multiply  in  excess.  .  .  .  The  inflam- 
matory reaction  does  not  respect  the  re- 
lative importance  of  the  tissues.  .  .  .  Hence 
inflammation,  though  biologically  an  adaptive 
and  preservative  process,  may  appear  harmful, 
requiring  the  intervention  of  medical  art.  Tak- 
ing all  things  into  consideration,  \\e  may  con- 
clude that  inflammation  is  a  reaction  to  local 
injuries,  calling  forth  protective  and  reparative 
measures ;  but  that  it  is  an  imperfect  patho- 
logical adaptation,  often  leading  to  consequences 
that  are  dangerous  per  se  and  defeat  its  purpose." 
Hektoen  and  Riesman  (9). 

As  this  is  true  for  the  tissues  in  general,  so 
does  it  apply  to  the  dental  pulp  in  particular. 

It  has  been  pointed  out  that  venous  hyper- 
aemia  may  soon  pass  into  a  condition  of  inflam- 
mation. A  brief  sketch  of  the  roles  that  are 
severally  played  by  (a)  the  blood  vessels,  (b)  the 
leucocytes,  (o)  the  exudates,  ((/)  the  fixed  cells, 
and  (e)  the  nervous  system  m  this  important 
condition  must  now  be  given. 

(a)  The  Blood  Vessels. — It  is  believed  that 
the  vessel  \\a\]s  are  structurally  altered  during 
the  course  of  inflammation  to  allow  of  and 
facilitate  the  emigration  of  the  blood  cells  and 
plasma.  Their  endothelial  cells  are  contractile 
(Klebs)  and,  according  to  Metchnikoff,  mobile 
and  phagocytic,  and  by  frequently  enlarging, 
cause  an  increased  resistance  to  the  vascular 
stream. 

{b)  The  le.ucocytes  play  a  fundamental  part 
in  the  process,  by  passing  mto  the  perivascular 
tissues,  as  first  pointed  out  by  Dutrocht  in 
1828.  Cohnheim  laid  great  stress  on  this 
phenomenon.  Detaching  themselves  from  the 
marginal  current,  which  they  normally  occupy 
on  account  of  their  low  specific  gravity,  they 
become  attached  to  the  enclothelial  lining  of  the 
walls ;  and,  as  a  result  of  a  localized  positive 
chemiotaxis    produced    by   diffusible    products 


of  bacteria,  drugs,  etc.,  emanating  from  the 
seat  of  the  lesion,  pass  through  the  inter-cellular 
cementing  substance. 

Leucocytic  emigration  is  a  complicated  pro- 
cess, and  varies  with  the  nature  of  cells  actively 
engaged  in  it ;  thus  there  may  be  more  eosino- 
philes  than  neutrophiles,  etc.  This  emigration 
is  favoured  by  the  dilatation  of  the  blood- 
vessels, and  the  contractility  and  mobility  of 
the  endothelial  cells ;  and  is  determined  by 
chemiotaxis,  by  which  the  leucocytes  advance 
towards  the  foci  of  greatest  attraction. 

Tlie  red  corpuscles  foUow  the  white  ones  at 
greater  or  shorter  intervals  of  time. 

Phagocytosis  is  the  action  of  certain  leuco- 
cytes and  wandering  cells — with  endothelial 
and  fixed  connective  tissue  cells  to  a  limited 
degree, — wliich  occurs  in  the  presence  of  patho- 
genic bacteria  and  other  particles  of  matter. 
A  kind  of  intra-cellular  digestion  takes  place, 
alexins — protective  bactericidal  bodies — being 
formed,  either  by  a  process  of  secretion,  or, 
as  Hardy  believes,  excretion,  and  the  adventi- 
tious material  being  destroyed.  Tlie  function 
is  carried  out  by  the  neutrophile  cells  and  the 
polymorphonuclear  leucocytes,  and  also,  per- 
haps, the  mononuclear  hyaline  cells.  Negative 
chemiotaxis,  the  antithesis  of  jjositive  chemio- 
taxis, implies  the  insensibility  of  phagocytes 
to  tlie  toxins  jiresent  in  any  particular  part. 

The  inflammatory  exudate  (plasnia)  ]3ossesses 
also  bactericidal  properties,  as  shown  by  the 
experiments  of  Buchner,  Xissen,  and  others, 
and  assists  the  phagocytes  in  their  beneficent 
work.  All  leucocytes  are  not  phagocytes — - 
eosinophiles  are  not ;  they  probably  possess 
excretary  functions,  and  may  diminish  the 
vitality  of  the  micro-organisms. 

(c)  The  inflammatory  exudates  contain  more 
proteids  than  physiological  lymph,  also  fibrin, 
iibrinoplastin,  etc.,  and  certain  digestive  fer- 
ments and  peptones,  etc.  The  quantity  is 
very  insignificant  in  the  pulp  tissue ;  the  serous 
and  sero-fibrinous  and  fibrinous  exudates  are 
small  in  quantity  and  poor  in  quality,  but  the 
haemorrhagic  exudates,  originated  by  the  in- 
tensity of  tlie  primary  lesion,  and  due  to  an 
enormous  diapedesis  of  the  red  corpuscles,  is 
very  marked.  After  traumatic  exposure  of  the 
pulp,  durmg  excavation  of  a  deep  carious 
cavity,  where  a  small  amount  of  dentine  re- 
mains in  the  floor,  there  is  often  a  large  flow 
of  arterial  and  caiiillary  blood,  signifying 
extensive  changes  in,  and  injuries  to,  the  vessel 
^^•alls,  and  also  a  large  quantity  of  haemorrhagic 
exudate. 

(rf)  Fixed  Tissue  Elements .—RetTogiessive  and 
progressive  changes  may  go  on  side  by  side, 
but  the  former  are  more  pronounced  in  the 
earlier  stages  of  acute  inflammation.  Inflam- 
mation follows    injuries    that    produce    lesions 


315 


not  sufficiently  great  to  induce  complete  necrosis 
or  death  of  the  part.  No  inflammation  of  the 
pulp  is  set  up  by  cocaine  pressure-anaesthesia ; 
it  is  anaesthetized,  and  removed  ahve.  But  in 
carious  encroachments  that  give  rLse  to  an  acute 
inflammation,  the  mesodermic  pulp  cells  become 
greatly  damaged  and  undergo  extensive  retro- 
gressive changes.  Necrosis  and  necrobiosis  of 
the  fixed  cells  and  leucocytes  occur.  The  odon- 
toblasts at  the  site  nearest  to  the  lesion  become 
fatty  and  degenerate  ;  while  further  away  they 
become  "  sheaved  ",  and  show  signs  of  prolifera- 
tion. This  is  probably  an  attempt  on  their  part 
to  heal  the  uijury  or  prevent  furtlier  damage  from 
taking  place  by  warning  the  pulp,  so  to  speak, 
of  the  oncoming  dangers ;  and  perhaps  even 
to  stimulate  the  dormant  dentine-depositing 
cells  arranged  about  them  to  functionate,  and 
produce  adventitious  dentine. 

(c)  That  the  nervous  si/stem  exercises  a  certain 
amount  of  influence  in  inflammation  cannot  be 
denied.  Hyperaemia  and  exudation  are  inter- 
fered with  by  the  uncontrolled  action  of  the 
vaso-con.strictors,  the  toxins  are  not  removed, 
and  repair  of  the  injury  cannot  be  proceeded 
with.  If,  on  the  othei  hand,  the  vaso-dilators 
exceed  their  functions,  congestion  takes  place 
enormously,  and  a  strangulation  of  the  vessels 
in  the  radicidar  region  soon  leads  to  moist 
gangrene  of  the  entire  organ. 

The  Galenic  signs  of  acute  inflammation 
are  manifested  m  the  pulp  as  in  the  other 
parts,  but  ^ary  greatly  in  intensity.  Thus 
pain  (dolor)  is  the  greatest,  whilst  swelling  and 
heat  {tumor  et  calor),  owuig  to  its  circumscribed 
environment,  are  the  least.  The  former  is  due 
to  the  pressure  upon  tlie  nerve  bundles,  and 
the  great  tension  caused  by  the  hyperaemia ; 
while  the  latter  are  due  to  hyjieraemia,  leuco- 
cytic  emigration,  serum  exudation,  prolifera- 
tion of  fixed  tissue  elements,  and  the  relatively 
large  amount  of  blood  in  the  part. 

The  Terminations  of  Inflammation 

The  effects  of  an  acute  inflammatory  attack 
upon  the  pulp  are  disastrous  to  that  tissue. 
It  is  too  small,  it  suffers  too  severely  and  too 
entirely,  its  reparative  powers  are  ordinarily 
too  feeble,  for  its  complete  recovery.  The 
whole  organ  is  usually  lost,  because  it  is  im- 
possible to  treat  at  all  satisfactorOjr  an  ulcer, 
say,  or  a  eircumseriljed  inflammation  of  its 
surface.  Hence  pulp  diseases  generally  end 
in  death,  with  or  without  suppuration,  as  the 
case  may  be.  Rarely,  however,  remarkable 
instances  of  the  partial  or  complete  healing  of  \ 
lesions  may  be  met  with.  Elsewhere  the  writer 
has  drawn  attention  to  these  reparative  pro- 
cesses (10).  It  would  seem  that  under  favour- 
able conditions,  when  a  large  area  of  the  pulp 
surface  has  been  exposed,  attempts  at  healing  [ 


begin  within  the  first  twenty-four  hours  after 
the  receipt  of  the  injury.  Organization  of  the 
inflammatory  i^roducts  has  taken  place.  A 
firm,  fine,  fibrous  stroma,  retaining  many  blood 
cells  and  much  exudation  in  its  reticulum,  may 
be  formed ;  or  the  surface  may  show  the  liisto- 
logical  character  of  ulceration,  many  layers  of 
degenerated  cells  and  pus  cells  being  produced ; 
while,  centrally,  masses  of  the  nature  of  calco- 
globulin  may  exist.  Black  and  Woodhead 
believe  that  these  nodules  are  associated  with 
the  venous  congestion,  and  are  analogous  to 
the  phleboliths  found  sometimes  in  varicose 
veins.  It  may  be  that  they  are  the  local  ex- 
pression of  all  that  is  implied  by  the  production 
of  callus  after  the  fracture  of  a  bone.  Russell's 
fuchsuie  bodies  are  also  occasionally  seen. 

At  times,  a  kmd  of  calcification  of  a  plastic 
exudation  may  heal  the  lesion,  as  reported  by 
Tomes  in  connection  with  a  case  extending 
over  three  years  :  at  times,  a  sort  of  catagmatic 
autoplasty  may  be  set  up  between  the  parts  of 
a  fractured  tooth  that  have  been  kept  in 
apposition  for  some  period  of  time  after  an 
accident.  In  these  latter  cases,  where  an 
impaction  of  the  fragments  has  occurred,  it  is 
probable  that  the  calcified  unitmg  material 
is  the  product  of  the  cells  of  both  pulp  and 
periodontal  memlirane. 

Generally  speakuig,  however,  acute  inflam- 
mation means  death  of  the  pulp,  especially  if 
there  has  been  any  considerable  amount  of 
serous  exudation,  for,  to  repeat,  this  organ 
possesses  no  lymphatics  to  carry  such  exudation 
off. 

In  many  instances,  nevertheless,  progressive 
metamorphoses  may  suiservene  on  an  '"  expo- 
sure "  of  the  pulp.  They  are  all  in  accordance 
with  the  laws  that  govern  cellular  prolifera- 
tion ;  viz.  that  they  follow  the  jjhysiological  types 
of  cellular  division ;  that  the  law  of  cellular 
specificity  is  usually  obeyed ;  that  ]5roliferation 
occurs  most  actively  in  young,  well-nourished, 
slightly  differentiated,  elementary  cells — such 
as  those  of  the  epithelium  and  connective 
tissues ;  and  that  proliferation  occurs  under 
conditions  that  are  opposed  to  those  that  kill 
the  cells,  such  as  dii'ect  traumatism  or  necrosis 
or  gangrene,  and  that  are  not  opposed  to 
those  that  stimulate  the  formative  activities, 
such  as  increased  function,  or  that,  if  con- 
tinued, operate  simultaneously  both  ways. 

These  metamorphoses  are  characterized  by 
the  formation  of  new  tissue,  apparently  for  tlie 
purposes  of  regeneration  or  replacement  of  old 
lost  tissue.  Thus,  surface  ef)ithelium  and  con- 
nective tissue  cells  are  remarkably  reparative. 
The  new  substance  is  called  granulation  tissue, 
and  is  found  developing  in  inflammatory  pro- 
liferations that  occur  in  large  coronal  cavities, 
principally    in    the    permanent    molar    series. 


316 


Clinically,  the  growth  (Roraer's  Pulpitis  granu- 
lomatosa,  14)  is  kno\vn  as  "  polypus  "  of  the 
pulp — an  incorrect  but  common  term.  It  is 
composed  largely  of  cells  of  the  mesodermic 
type  of  variable  size,  round  or  oval,  derived 
diiectly  from  pre-existing  cells  and  chiefly 
concerned  in  the  formation  of  the  bulk  of  the 
mass  of  the  new  tissue ;  of  the  plasma  cells  of 
Umia ;  of  many  polymorphonuclear  hyaline 
leucocytes ;  of  large  mononuclear  hyaline  leu- 
cocytes, which  are  considered  by  MetchnikofT 
to  be  able  to  become  transformed  into  fixed 
comiective  tissue  cells;  of  "mast-cells"  so- 
called;  and,  finally,  if  necrotic  material  is 
present,  or  if  foreign  bodies — e.  g.  a  splinter  of 
dentine — exist,    of    multinucleated     giant-cells, 


Fig.  406. — Cliroaic  inflammation  of  the  pulp. 
D,  Dentine ;  P,  Pulp ;  E,  Epithelium.      X  45 

whose  function  is  somewhat  of  a   phagocytic 
type. 

This  granulation  tissue  undergoes  but  little 
change  after  it  has  once  formed.  It  slowly 
increases  in  bulk  until  it  may  actually  rise 
above  the  lunits  of  the  walls  of  the  cavity  and 
extend  over  its  sides.  Its  free  surface  usually 
has  upon  it  some  degenerated  cells  and  pus 
corpuscles ;  but  when  it  has  come  into  direct 
contact  with  the  epithelium  over  the  surface 
of  the  gum  near  by,  either  as  a  consequence  of 
the  destruction  of  the  dentinal  wall  beneath 
the  gingival  margm,  or  as  the  result  of  exuberant 
granulation  tissue  spreading  itself  over  the 
sides  of  the  wall,  it  acquires  an  epithelial  cover- 
ing of  cells,  which  may  form  a  single  or  several 
layers,  or  even  copy,  with  faithful  accuracy, 
the  normal  oral  epithelium  of  the  neighbour- 
hood.    The  presence  of  this  adventitious  epi- 


thelium on  the  surface  of  a  mesodermic  body 
was  formerly  attributed  to  the  results  of  skm- 
graftmg ;  but  it  is  in  consequence  of  the  irrita- 
tion of  a  sharp  dentinal  edge  that  the  implanta- 
tion of  new  cells  occurs,  and  growth  begins, 
the  latter  passing  by  an  unbroken  continuity 
from  the  gingival  margm  over  the  edge  and 
on  to  the  pulp  surface. 

THE  RETROGRESSIVE  CHANGES  IN  THE  PULP 

Anabolic  metabolism  of  the  cells  of  the  pulp — 
as  in  cells  generally — gives  rise  to  certain  activ- 
ities, which  carry  on  the  proximate  principles 
underlying  nutrition,  function,  and  reproduc- 
tion. The  direct  result  of  disturbances  in  the 
activities  of  cells  leads  to 
different  varieties  of  dis- 
integration and  atrophy 
and  death.  These  are 
retrogressive  changes, 
which  are  distinguished 
from  progressive  changes, 
inasmuch  as  the  latter 
are  concerned  in  building 
up  alinormal  growths  and 
j)roliferations.  The  death 
of  cells  may  be  occa- 
I)  sioned  :  (1)  directly  and 
rapidly,  ajjart  from 
morbid  changes  taking 
place  in  cellular  struc- 
tures— this  is  necrosis,  as 
exemjjlified  in  the  appli- 
cation of  .strong  caustics 
or  arsenious  acid  ;  or  (2) 
indirectly  and  slowly, 
either  by  atrofhy,  or  by 
a  gradual  shrinking  of 
their  size,  or  by  altera- 
tions in  structure  produc- 
ing either  degeneration 
through  the  oncoming  of  certain  abnormal 
chemical  processes  in  the  protoplasm,  or  infiltra- 
tion, that  is,  the  deposition  of  foreign  materials 
from  without — this  is  necrobiosis,  and  is  ex- 
emplified in  many  of  the  degenerations,  such  as 
fibroid,  fatty,  and  the  like  (18). 

Imperfect  nutrition  induces  atrophy,  which 
in  its  turn  may  lead  to  necrobiosis  or  destruction 
of  cells.  Perverted  intra-cellular  metabolism 
produces  degeneration  of  the  protoplasm,  which 
is  conv'erted  into  abnormal  and  useless  sub- 
stances; this,  too,  may  terminate  in  necrobiosis. 
Infiltration  favours  the  death  of  cells. 

For  a  long  time  it  has  been  known  that  the 
pulp  is  peculiarly  liable,  on  account  of  the 
unique  nature  of  its  circulatory  apparatus,  to 
undergo  necrobiosis  through  degeneration  and 
infiltration.  Many  teeth,  apparently  not  in- 
fected   by    disease,    in    old    and    young    alike. 


317 


reveal  this  condition,  wliich  has  been  described 
by  Weil  as  reticulai-  atrophy,  and  by  the  wTiter 
as  fibroid  degeneration.  It  wiU  now  suffice 
briefly  to  indicate  the  pathological  lesions  that 
manifest  themselves  in  connection  with  this 
common  condition. 

Four  main  types  have  been  observed  : 
Fibroid,  Atrophic,  Fatty,  and  Hyaline  or  Colloid. 

The  Degenerations 

1.  Fibroid  Degeneration  or  Sclerosis. — This 
probably  occurs,  in  the  first  place,  as  a  complica- 
tion of  thrombosis  of  the  capillaries  and  veins, 
and  permanent  dilatation  of  the  arteries  through 
atony  (due  to  impairment  of  the  vaso-motor 
mechanism)  or  disease  of  the  walls,  with  or 
without  minute  haemorrhages.  It  seems  often 
to  be  succeeded  or  accompanied  by  a  con- 
densation or  fibrification  of  the  pulp-tissue 
that  lies  between  the  basal  layer  of  Weil  and 
the  substance  of  the  pulp  proper.  A  hyper- 
plasia of  the  connective  tissue  fibres  of  the  parts 
occurs.  "  Sheaving  "  of  the  odontoblasts,  with 
or  without  fatty  degeneration,  permanent  dis- 
tension of  the  arteries  and  arterioles,  and  rapid 
overgro\\th  of  the  fibrous  tissue,  supervene, 
until  a  well-marked  reticular  atrophy  appears, 
and,  m  later  stages,  complete  fibrosis  of  the 
organ,  \\  ith  disappearance  of  all  cells  and  nuclei 


Fio.  407. — Longitudinal  section  of  fibroid 

degeneration  of  the  pulp. 

D,  Dentine ;  P,  Pulp.      X  45. 

and  every  vestige  of  nerve  bundle  and  vascular 
system. 

The  condition  may  be  considered  to  be  a 
natural  old-age  termination  of  the  life  of  a 
healthy  pulp,  dependent  not  upon  the  age  of 


its  possessor,  but  on  the  constitutional  lesions 
already  noted.  In  complete  fibrosis  no  traces 
of  cellular  organization  of  cell  nuclei,  or  inter- 
stitial cementing  substance,  can  be  found  any- 
where.    Nerve    fasciculi,    odontoblasts,     pulp 


Fig.  408. — Transverse  section   of   fibroid 

degeneration  of  the  pulp. 

D,  Dentine.      X  45. 

cells,  blood  vessels,  equally  share  the  process 
of  fibrification,  and  are  no  longer  recognizable 
under  the  microscope.  But  the  connective 
tissue  stroma,  which  is  merely  a  loose  net\vork 
in  normal  circumstances,  has  either  become 
grossly  hyperplasic  or  quite  obliterated,  and 
its  place  occupied  by  a  new  firm  fibrous  struc- 
ture devoid  of  cells,  nuclei,  or  any  regular 
arrangement  of  the  constituent  parts.  Large 
alveolar  spaces  (areolae)  appear ;  rows  of  long 
thick  fibres  of  various  shapes  and  sizes,  some 
bifurcated,  others  plain,  others  possessing 
fibrous  offshoots,  are  visible;  the  odontoblasts 
are  "'.sheaved"  at  first,  and  then  reduced  to 
thin  fibrous  cords  or  bundles  of  fibres.  The 
areolae  at  times  may  measure  from  220  ^  x  160  /x 
to  X  10  /i  5  /x,  and  abound  in  the  central  portions 
of  the  pulp  in  the  \acinity  of  the  blood  vessels 
and  nervous  systems.  The  basal  layer  of  WeU 
and  the  odontoblasts  themselves  are  the  last 
to  undergo  the  change.  As  has  already  been 
pointed  out,  complete  fibrosis  may  occur  in 
deciduous  teeth. 

2.  Degenerative   Atrophy  of   the   Pulp. — This 


318 


is  similar  to  the  preceding,  and  has  been  care- 
fully demonstrated  by  Wedl  (21)  and  Walkhoff 
(20).  Shrinkage  of  the  odontoblasts  is  followed, 
later  on,  by  their  total  disappearance.  The  freely 
anastomosing  capillaries  in  the  peripheral 
regions  often,  even  before  dilatation,  present 
varicosities  through  contraction  of  the  con- 
nective tissue  stroma.  The  pulp  beneath  the 
odontoblasts  becomes  condensed  and  infiltrated 
with  cells,  and  vacuolation  of  the  healthy 
tissues  occurs.  Rothmann  (15)  describes  an 
Atrophia  pulpae  sderoticans,  which  bears  a 
general  resemblance  to  this  condition,  especially 
as.  if  chronic,  it  passes  into  a  state  of  complete 
fibrosis — the  cellular  elements  diminishing  in 
size  and  numbers,  and  the  normal  connective 


i'lG.  40y. — Two  solid  pulp  nodules 
P,  Pulp ;   N,  Nodules.      X  45. 

tissue     fibres     becoming     coarsely     fibrUlated. 
Calcific    deposition    often    takes    place    simul-   ' 
taneously. 

3.  Fatly  Degeneration. — This  is  an  incidental 
necrobiotic  condition  in  senile  permanent 
teeth  and  deciduous  teeth  undergoing  absorp- 
tion, and  in  pulps  whose  "  exposures  "  have 
been  "capped".  The  pulp  recedes  from  the 
dentinal  walls,  and  is  of  a  pale  colour ;  the 
odontoblasts  are  degenerated,  and  fat  globules 
appear  in  their  substances  and  interstitially, 
and  the  walls  and  sheaths  of  the  capillaries 
and  nerves  undergo,  to  some  extent,  a  form  of 
degenerative  lipogenesis.  Accordmg  to  Thoma 
(18),  "  in  fatty  infiltration  free  fat,  deposited 
in  the  form  of  drops,  may  be  formed  from  an 
excess  of  circulatory  albumen,  while  in  albumin- 
ous and  fatty  degeneration  the  organized  albumen 


is  attacked  and  broken  up  into  granular  albumin 
ous  or  albuminoid  and  fatty  molecules."     It  is 
this  latter,  and  not  the  former,  condition  that 
obtains  m  the  dental  pulp,  and  even  there  only 
to  a  very  limited  degree. 

4.  Hyaline  or  Colloid  Degeneration. — The 
writer  possesses  a  section  of  which  the  histological 
elements  exhibit  appearances  dissimilar  to  the 
above,  tlnis  enabluig  the  condition  to  be  placed 
in  a  different  category.  The  pulp  appeared 
to  present  signs  of  undergoing  what,  in  the 
absence  of  a  further  classification,  may  be 
described  as  a  hyaline  or  colloid  degeneration 
of  its  elements.  It  is  probably  a  coagulated 
fibrinous  exudation,  which  subsequently  be- 
comes hyaline  m  character,  and  bears  a  super- 
ficial resemblance  to  the 
hyaline  tube-casts  found 
in  disease  of  the  renal 
glomeruli,  or  in  the 
alveoli  of  the  thyreoid 
gland. 

The  degenerations 
briefly  described  repre- 
sent in  the  pulp  certain 
disturbances  of  tissue 
nutrition  that  are  retro- 
gressive, as  opposed  to 
progressive  or  formative 
metamorphoses.  They 
are  unexposed  to  ex- 
ternal influences,  are  not 
dependent  on  bacterial 
cau.ses,  and  possess  no 
clearly  marked  symp- 
toms, bemg  capable  only 
of  being  demonstrated 
post  mortem. 

Calcification,    Petrifaction, 
or  Calcareous  Infiltration 

Common  as  is  fibrosis 

of     the     pulp,    perhaps 

even  more  general  is  that  pathological  condition 

which  has  been  variously  described  as  calcareous 

infiltration  or  calcification  of  the  pulp. 

The  former  presents  no  operative  difficulties ; 
the  removal  of  pulps  affected  by  what  may  be 
termed  soft  degenerative  processes  is  easy  of 
accomplishment  and  can,  as  a  rule,  be  thoroughly 
carried  out.  This  is  not  so,  however,  \\ith 
the  latter ;  repeated  attempts  at  devitalization 
of  the  sensitive — even  hypersensitive — surface 
are  often  required  to  achieve  the  end  in  view. 

It  would  save  a  confusion  of  ideas  if  three 
kinds  of  calcific  deposition  were  generally 
recognized  :  (I)  Calcareous  mfiltration,  entirely 
produced  by  changes  in  the  pulp  alone — a 
constant  accompaniment  of  caries,  but  also 
found  occasionally  in  apparently  sound  teeth 
as  the  result  of  vascular  changes  due  to  con- 


319 


stitutional  or  idiopathic  causes ;  (2)  secondary 
dentine,  occurring  not  only  as  a  pathological 
process  in  cases  of  attrition,  abrasion,  or  fracture, 
but  physiologically  as  the  result  of  senOe 
changes  in  permanent  and  in  long-retained 
deciduous  teeth ;  and  (3)  adventitious  dentine 
the  product  of  caries  solely. 

Under  the  microscope,  pulps  affected  by 
calcification  present  in  varying  degrees  the 
appearance  of  nodules,  smooth  and  round  or 
irregular,  solid  or  hollow,  attached 
or  unattached  to  the  dentinal  waUs, 
transparent,  laminated,  or  granular. 
They  are  frequently  very  refractUe  and 
exceedingly  hard — as  hard  as  the  neigh  - 
bouring  dentine.  They  arise  in  all 
cases — either  partially  or  completely 
filling  up  the  pulp-cavity,  or  arranged 
in  masses  or  clusters  or  fused  together 
into  homogeneous  \^liole,  or  large  or 
small — from  the  deposition  of  finely 
granular  particles  of  carbonate  and 
phosphate  of  lime  between  the  cells 
and  fibres  of  the  pulp.  Their  frequent 
presence  in  this  region  is  no  doubt 
due  to  the  fact  that  there  is  a  pro- 
pensity, elevated  in  early  stages  of 
life  into  an  actuality,  for  the  pulp 
cells  to  be  concerned  in  the  buUding- 
up  of  hard  dense  osteoid  substances ; 
and  their  histological  resemblance  to 
the  dentinal  walls  of  the  teeth  is  at 
times  particularly  striking.  Thus,  not 
only  are  they  marked  by  more  or  less 
concentric  laminae,  but  they  contain 
radiating  tube-like  lines,  which  may  be 
actual  tubes  or  merely  traces  of  con- 
nective tissue  fibres,  which,  partially 
stiffened  by  impregnation  ^\ith  lime 
salts,  have  become  incorporated  in 
the  general  calcification.  It  is  possible 
to  stain  them  with  borax-carmine,  but 
an  immersion  for  years  is  required  to 
render  them  apparent.  It  is  impos- 
sible to  say  ^^■hether  they  are  hollow ; 
the  probability  is,  however,  that  they 
are  solid  structures. 

Calcification  may  exist  in  one  or  two 
teeth  in  a  given  denture  ;  or  it  may  affect  many, 
or  even  all.  There  are  usually  pronounced 
clinical  symptoms,  which  come  on  after  the  en- 
largements of  the  nodules  have  produced  some 
considerable  pressure  m  the  pulp  cells  and  fibres. 
It  is  not  known  whether  the  actual  mechanical 
pressure  of  the  nodules  on  the  nerve  l)undles 
in  the  immediate  vicinity  (thus  producing  a 
slight  amount  of  nerve  stretching)  sets  up  pain 
and  discomfort ;  or  whether  pam  may  be  due 
to  an  increased  volume  of  tissue  ui  the  pulp 
effecting  an  alteration  in  the  blood  pressure. 
Probably  both  factors  are  in  operation,  espe- 


cially the  former,  as  instances  occur,  in  other 
parts  of  the  body,  of  pain  being  induced  by  the 
slow  gradual  pressure  on  nerve  trunks  issuing 
from  foramina — say,  in  the  skull — where  symp- 
toms of  epileptiform  neuralgia  are  produced. 
Pain  may  also  be  due  to  mere  mechanical 
pressure  on  the  pulp  itself,  induced  by  the  en- 
croachments made  upon,  and  the  diminution 
of,  the  cubic  contents  of  that  organ. 

The     interest     of    this    retrogressive     meta- 


Fiii.  41U. — Calcification  of  tho  pulp. 
P,  Pulp;   N,  HoUow  nodule.      X  90. 

morphosLS  lies  in  this  element  of  pain,  which  is 
almost  always  manifest  in  the  later  stages. 
The  change  is  due  to  a  general  circulatory 
cause,  viz.  lime  salts  ch-culating  in  solution  in 
the  blood,  and  is  proljably  associated  with  the 
gouty  or  rheumatic  diathesis.  In  this  respect 
it  is  probably  analogous  to  those  bodily  condi- 
tions that  give  rise  to  arterioliths  and  phlebo- 
liths  in  arteries  and  vehis,  and  the  concretions 
that  at  times  occur  in  the  efferent  ducts  of  the 
parotid  and  other  salivary  glands,  in  the  urinary 
passages,  and  in  the  bUe-ducts  of  the  gall- 
bladder. 


320 


Necrosis  and  Putrefaction  of  the  Pulp 

Tliis  proceeds  very  rapidly  by  means  of  three 
■distinct  chemical  and  biological  stages — primary, 


Fig.  411. — Complete  calcification  of  the  pulp. 
E,  Enamel;  D,  Dentine;  AD,  Adventitious  dentine. 

secondary,  and  final.  The  fir.st  begins  as  a 
post-mortem  change,  and  does  not  necessarily 
depend  upon  the  presence  of  schizomycetes, 
the  fact  being  that  both  the  liquid  and  solid 
constituents  of  the  pulp,  immediately  after  its 
death,  are  capable  of  destroying  many  micro- 
organisms. The  changes  partake  more  of  a 
chemical  dissolution  than  a  result  of  bacterial 
infection,  and  are  dependent  upon  the  action 
of  the  unformed  soluble  ferments  found  in 
the  pulp,  as  in  other  soft  tissues  of  the  body. 
Tliese  soluble  ferments  or  enzymes  are  present 
in  all  living  tissues,  and  have  a  great  deal  to 
■do  with  the  processes  of  metabolism.  Thus 
■albumen  becomes  converted  by  these  enzymes 
into  peptones  and  hemi-albumens,  and  this 
probably  sums  up  the  changes  in  the  early 
stages. 

Pathogenic  bacteria  are  capable  of  developing 
in  tlie  soft  parts  and  producing  the  changes 
just  noted ;  but  in  order  that  they  may  develop 
sufficiently  to  produce  these  chemical  stages 
in    sufficient    amount    before    they    themselves 


are  destroyed,  there  must  be  some  local  focus 
of  disease  or  area  of  chemical  decomposition 
present,  which  becomes  largely  invaded  by  the 
pus-forming  micro-organisms. 

It  is  therefore  obvious  that  if  the 
balance  between  the  biological  actions  of 
the  invading  and  invaded  forces  is  mam- 
tained  in  equilibrium,  simple  death  of 
the  pulp  will  occur ;  that  is,  its  general 
functions  will  cease,  its  physiological 
resistance  to  disease  or  injury  will  be  in 
abeyance,  its  powers  of  undergoing  pro- 
gressive or  further  retrogressive  meta- 
morphoses will  be  ended,  and  it  will 
remain,  perhaps  for  many  years,  an  inert, 
innocuous,  ineffectual  remnant  of  its 
former  self — pale  and  shrunken.  The 
hard  parts  surrounding  it  will,  at  the 
same  time,  be  affected  by  the  loss  of 
nutrition,  and  the  enamel — probably 
through  changes  in  the  subjacent  dentine, 
certainly  not  through  actual  alteration  in 
its  own  structure  or  chemical  composition 
— wUl  become  dark  and  lustreless. 

On  the  other  hand,  if  the  bacterial 
infection  is  great  and  the  albuminoid 
bodies  produced  are  voluminous  in 
amount,  toxic  enzymes  result.  These 
are  very  active  poisons,  which  give  rise 
in  a  short  space  of  time  to  the  usual 
chemical  products  of  decomposition,  viz. 


X  45. 


Fig.  412. — Vertical  section  of  necrotic  pulp 
M,  Masses  of  micro-organisms.      X  45. 

carbonic  acid,  ammonia,  sulphuretted  hydrogen, 
and  certain  other  salts  and  water.  The  evolu- 
tion of  these  is  dependent  upon  the  access  of 
oxygen,  heat,  and  moisture. 


321 


The  chemical  changes  of  putrefaction  are 
those  of  hydration — the  taking-up  of  one  or  two 
molecules  of  water ;  reduction — the  breaking-up 
and  decomposition  by  nascent  hydrogen ;  and 
oxidation — the  formation  of  carbonic  acid, 
acetic,  nitrous,  nitric,  and  similar  acids.  Other 
substances  manufactured  simultaneously,  in 
varying  degrees,  are  globulins,  toxic  enzymes, 
peptones,  the  nitrogenous  amido-acids,  leucin 
and  tyrosin,  the  nitrogenous  amines,  niethyl- 
amine,  propylamine,  etc. ;  and  organic  and  fatty 
acids,  such  as  formic,  propionic,  butyric, 
valerianic,  palmitic,  and  other  fatty  acids ;  and 
also  putrescLtie  (C^HjoN.,)  and  the  isomers, 
cadaverine  and  neuridine  (CjHjjN.,).  These 
substances  quickly  become  converted  into 
ammonia  and  its  derivatives. 

Buckley  believes  that  not  only  is  the  pulp 
tissue  thus  destroyed,  but  the  contents  of  the 
dentinal  tubules  also ;  and  that  the  pulp- 
chamber,  the  root-canals,  and  the  dentinal 
tubules,  are  more  or  less  filled  with  these 
end-products  of  decomposition  (2)  (3)  (4). 

A.  H-S. 

BIBLIOGRAPHY 

(1)  BizzozEBO.      Virchoius  Archiv.,  Vol.  XC. 

(2)  BocKLEY.     Trans.    Fourth   International    Dental 

Congress.     Dental  Cosmos,    1905,  Vol.  XLVII, 
p.  223. 

(3)  Buckley.     Dental  Cosmos,    1905,    Vol.    XLVII, 

p.  1302. 


(4) 
(5) 

(6) 


BtJCKXEY.     Johnson's  Operative  Dentistry. 
Bukchard-Inglis.     Text-book  of  Dental  Pathology 

and  Therapeutics,  1908. 
CoHNHEiM.     Archiv.  fiir  Pathol.  Anat.,  Vol.  XV, 

1867,  andXLV,  1869. 

(7)  Eberth  AND  ScHiMMELBUSCH.     Virchow's  Arckiv., 

Vol.  cm. 

(8)  Fischer     und     Laxdois.     Zur     Histologie     der 

Gcsunden  und  kranken  Zahnpulpa,  1908. 

(9)  Hektoen-  .\nd  Riesman.     A  Text-book  of  Patho- 

logy, 1901. 
(10)  Hopewell-Smith,  A.     The  Histology  and  Patho- 
Histology  oj  the  Teeth  and  Associated  Parts,  1903. 

Hopewell-Smith,  A.  The  Pathology  of  the  Pulp 
in  Relation  to  Clinical  Dental  Surgery  ;  Pyor- 
rhoea Alveolaris  ;  and  other  Essays.    1911. 

Metchnikoff.  L'Imniunite  dans  les  Maladies 
Infectieuses,  1904.  Pathologic  comparative  de 
V  Inflammation,  1891. 

Osler.  Cartwright  Lectures  on  the  Physiology 
of  the  Blood  Corpuscles.     Medical  News,  1886. 

RoMER.  Ueber  die  Pathologie  der  Zahnpulpa. 
Trans.  Fifth  International  Dental  Congress, 
Berlin,  1909.  Atlas  der  pathologisch-anatom- 
ischen  V erdnderungen  der  Zahnpulpa,  1909. 

RoTHMANN.  Patko- Histologic  der  Zahnpulpa  u. 
Wurzelhaut,  1889. 

Sieberth.     Mikro-organismen    d.  kranken   Zahn- 
pulpa, 1900. 
)  Tanzer.      The     Increased     Intra-dental     Blood 
Pressure.     Oester-Ung.      Vierteljahrsschrift     fitr 
Zahnheilkunde.      1906. 

Thoma.  General  Pathology  and  Pathological 
Anatomy.     1896. 

Tomes  and  Nowell.  A  System  of  Dental  Surgery. 
1906. 

(20)  Walkhoff.  Mikrophotographischer  Atlas  d.pathol. 

Histologie  Menschlichcr  Znhne,  1901. 

(21)  Wedl.     Pathologie  der  Zahne,  1903. 


(11) 


(12) 


(13) 
(14) 


(15) 
(16) 
(1 


(18) 
(19) 


11 


CHAPTER  XYII 


THE   DENTAL   OPERATING   ROOM:    ITS    APPOINTMENTS 

AND   HYGIENE 


The  choice  of  the  operating  room  is  a  matter 
of  very  great  importance  to  the  dental  surgeon, 
inasmuch  as  he  ]ias  to  spend  the  great  part  of 
his  working  life  in  it.  The  room  selected  should 
be  of  good  size  and  well  ventilated ;  it  should 
liave  the  advantage  of  whatever  public  services 
there  may  be  in  the  district,  such  as  gas,  water, 
electricity,  etc.,  and  a  satisfactory  drainage  for 
the  wash-basin  and  fountain  spittoon. 

Light 

Natural. — A  good  light  is  an  absolute  neces- 
sity, and  there  are  certain  conditions  which  must 
be  fulfilled  if  the  lighting  of  the  room  is  to  be 
satisfactory. 

(1)  The  amount  of  light  must  be  sufficient 
for  the  operator  to  see  all  the  details  of  his  work, 
but  should  not  be  great  enough  to  cause  "  glare  "  ; 
as  a  matter  of  fact,  this  is  unlikely  with  anything 
short  of  direct  sunlight. 

(2)  The  actual  area  of  operation  must  be 
the  most  brightly  illuminated  jjart  of  the 
operator's  field  of  view.  This  is  a  most  im- 
portant condition,  because,  if  other  parts  of 
the  fi(  Id  of  view  are  brighter  than  the  operation 
area,  that  area  will  by  contrast  appear  darker 
than  it  really  is,  and  fatigue  and  eye-strain  may 
be  caused  by  the  extra  effort  that  has  to  be 
made. 

(3)  The  light  must  be  diffused,  that  is,  it 
must  come  from  a  source  large  enough  to  sub- 
tend a  wide  angle  at  the  chair  head-rest,  or  else 
from  several  sources  at  sufficient  distance  from 
one  another  to  produce  the  same  effect.  If 
the  light  comes  from  too  small  a  source  it  tends 
to  make  all  shadows  of  an  equal  degree  of  black- 
ness ;  a  more  diffused  light  will  cause  a  grading 
of  the  shadows  corresponding  with  the  different 
amounts  o{  surface  irregularity  that  cause  them. 
This  is  the  reason  why  a  diffused  light  w  ill  show 
the  details  of  a  cavity  better  than  that  coming 
from  a  single  lamp,  however  powerful.  If 
pushed  beyond  a  certain  point,  diffusion  of  light 
tends  to  obscure  detail  by  lighting  hollows  and 
projections  alike,  as  everyone  kno-\\'s  who  has 
tritd  to  make  out  the  surface  details  of  a  crown 
in  a  hot  furnace. 

The  fulfilment  of  these  conditions  will  depend 
partly  on  the  window  and  the  ))osition  of  the 
chair  in  relation  to  it,  and  ])artly  on  the  sur- 


roundings   of    the    chair,    including    the    wall 
decorations. 

The  window  should  be  of  good  size,  say  not 
much  less  than  5A  ft.  by  4J,  with  its  lower  mar- 
gin not  more  than  3J  ft.  from  the  floor,  and  it 
should  command  a  view  of  sky  unobstructed 
by  buildings  or  trees.  There  appears  to  be 
some  difference  of  ojsinion  as  to  what  is  the 
best  aspect,  but  anything  between  north  and 
east  or  even  south-east  will  ans^\er  the  purpose. 
If  one  is  obliged  to  have  a  window  with  such 
an  asjject  that  sunlight  falls  on  the  chair  during 
part  of  the  day,  much  may  be  done  to  mitigate 
the  glare  by  the  use  of  shades  or  of  some  kind 
of  window  glass  that  breaks  ujj  the  direct  rays 
of  the  sunlight. 

The  chair  should  be  placed  facing  the  window 
and  near  to  it  in  such  a  way  that  while  the  light 
falls  full  on  the  work,  no  part  of  the  ^\•inclow  is 
in  the  operator's  field  of  view  while  he  is  in  his 
usual  position  of  "right  side  front".  A  bay 
window  is  not  altogether  satisfactory  in  this 
respect,  although  it  gives  a  large  quantity  of 
light.  Besides  the  main  window,  there  need 
be  no  others  in  the  room  at  all.  There  %\ill  be 
no  actual  disadvantage  in  having  extra  windows 
at  the  operator's  back,  but  should  there  be  any 
facing  him,  they  shoidd  be  fitted  with  opaque 
blinds  that  will  completely  shut  the  light  from 
them  during  working  hours. 

The  surroundings  of  the  chair  and  the  wall 
decorations — that  is,  everything  that  helps 
to  form  the  background  to  the  actiuil  work — 
should  be  of  some  quiet  tone ;  this  does  not 
necessarily  mean  dull  and  inartistic,  but  it 
does  mean  that  there  should  be  nothing  glaring 
or  glittering ;  Black  says  very  truly  that  the 
worst  possible  wall  surface  would  be  glazed 
white.  There  is  perhaps  too  much  tendency 
at  the  present  day  to  use  ^^■hite  enamel,  white 
tiles,  white  opal  glass,  and  such-like  materials. 
These  things  no  doubt  show  the  dirt  better 
than  dark  t-n  s,  and  in  that  way  may  be  a  useful 
means  of  educaticn,  both  to  the  dental  surgeon 
and  to  the  public  ;  but  anyone  who  really  under- 
stands surgical  cleanliness,  can  just  as  easily 

i    keep  a  dark  object  in  a  clean  condition  as  a 

]   light  on". 

Artificial. —  In  most  localities  artificial  light 
will  be  requind  at  some  time  or  other.     Inas- 

22 


323 


much  as  the  intensity,  position,  and  size  of  the 
ilhiminating  agency,  can  be  controlled,  there 
need  be  no  difficulty  in  getting  a  light  satis- 
factory for  \\ork.  Here  again  the  same  rules 
must  be  followed  in  the  matters  of  sufficiency  and 
diffusion  of  light,  and  relative  brightness  of  the 
operation  field.  Most  of  the  methods  of  arti- 
ficial lighting  in  common  use  transgress  these 
rules  to  some  extent.  If  the  source  of  light 
be  a  single  lamp,  or  several  close  together,  there 
will  be  insufficient  diffusion  of  light,  and  the 
operator  will  experience  difficulties  from  the 
blackness  and  definition  of  the  shadows ;  he 
will  be  constantly  getting  in  his  own  light,  and 


Fig.  413. 

moreover  A\ill  find  that  even  with  a  brilliant 
lamp  it  \\'i!l  be  difficult  to  see  clearly  the  details 
of  his  work,  especially  if  he  is  doing  a  gold  filling. 
\'ery  often,  in  order  to  get  intensity  of  illumi- 
nation, the  lamp  is  brought  too  close  to  the  work, 
and  consequently  is  liable  to  come  into  the 
opera  tors  field  of  view. 

Inasmuch  as  the  dentist  has  arranged  both 
the  chair  and  his  o\\'n  position  in  relation  to  the 
window  for  daylight  work,  the  ideal  artificial 
light  shoidd  also  come  from  the  \\-indow,  and  that 
not  from  one  point  of  it,  but  from  all  the  corners 
of  its  upper  half,  so  as  to  imitate  as  far  as 
possible  the  directions  of  the  rays  of  daylight 
that  pass  through  the  window  from  the  sky. 

By  far  the  best  artificial  light  the  \\riter  has 


ever  worked  by  is  afforded  by  six  fifty-candle- 
power  glow-lamps,  attached  to  alight  rectangu- 
lar frame  4i  ft.  broad  and  3  ft.  high,  hung  just 
inside  the  upper  part  of  the  window,  and  capable 
of  being  moved  up  or  down  some  little  distance. 
The  lamps  are  arranged  one  at  each  corner,  and 
one  in  the  middle  of  each  horizontal  side.  (See 
Fig.  413.)  The  light  from  this  arrangement  is  very 
soft  and  easy  to  «'ork  by,  producing  no  feeling  of 
strain  to  the  eyes  and  causing  neither  more  nor 
less  shadow  than  the  ordinary  diffused  daylight 
coming  from  the  window.  For  instance,  an 
ordinary  small  instrument  .such  as  an  excavator 
held  just  in  front  of  a  piece  of  ^\•hite  paper  on 
the  head-rest  casts  hardly  any  shadow  at  all. 
Wliatever  lamps  are  used,  they  should  be  sur- 
rounded by  fro.sted  globes  of  fair  size,  to  prevent 
the  patient  being  dazzled  by  the  intense  bright- 
ness of  the  filaments,  or  mantles.  If  this  is 
done  there  need  be  little  fear  of  having  too 
powerful  a  light.  As  a  matter  of  fact  many 
lights  in  common  use  do  not  give  sufficient  illu- 
mination, although,  on  account  of  being  too 
close  and  not  shaded,  they  may  be  dazzling  to 
both  patient  and  ojierator. 

In  arranging  the  other  appointments  of  the 
room,  and  in  the  general  conduct  of  dental 
operations,  three  considerations  demand  atten- 
tion. These  are  the  comfort  of  the  patient,  the 
comfort  and  convenience  of  the  operator,  and 
cleanliness. 

The  comfort  oj  the  patient,  altiiough  a  most 
important  matter,  can  be  dismissed  in  a  few 
words.  In  the  general  fittings  and  appearance 
of  the  room  any  suggestive  display  of  instru- 
ments or  appliances  should  be  avoided.  Al- 
though the  dental  surgeon  likes  to  be  up  to 
date,  he  must  always  remember  that  the  apjja- 
ratus  he  is  so  proud  of  seems  to  many  people 
nothing  but  a  collection  of  instruments  of  tor- 
ture ;  to  some  nervous  patients  the  v^ery  odour 
of  a  dentist's  room  may  suggest  all  sorts  of 
horrors.  Much  discomfort  may  be  saved  the 
patient  by  proper  adjustment  of  the  chair, 
especially  of  the  head-rest.  This  should  always 
be  arranged  so  that  both  head  and  neck  are 
^\•ell  supported ;  if  only  the  head  is  supported, 
the  neck  has  to  be  kept  stiff  by  muscular  effort, 
which  soon  causes  great  fatigue.  One  of  the 
most  comfortable  tj-pes  is  the  \\'ell-known  "  roll  " 
head-rest,  which  has  the  additional  advantage 
of  serving  as  an  arm-rest  for  the  operator.  In 
cold  weather  a  foot-warmer  or  rug  will  prove 
of  great  use  ;  it  is  not  always  jjleasant  to  sit 
for  an  hour  or  so  on  a  cold  winter's  day  with  the 
feet  to^\ards  a  window.  It  need  liardly  be 
suggested  that  time  and  pain-.saving  a])pliances 
and  methods  should  be  used  to  tlic  utmost 
possible  ext(  nt . 

The  convenience  and   comfort  of   the   operator 


324 


depend  largely  on  the  efiSciency  and  methodical 
arrangement  of  his  instruments.  Everything 
should  be  in  perfect  condition  and  exactly 
in  the  jDlace  where  he  expects  to  find  it,  so  that 
he  does  not  waste  time  groping  for  things, 
perhaps  first  in  one  drawer  and  then  in  another. 
The  cabinet  should  be  placed  so  that  instru- 
ments can  be  reached  from  it  without  the 
operator  moving  his  position  at  the  chair  side  ; 
this  may  seem  to  some  a  trifUng  matter,  but 
the  extra  work  of  moving  backwards  and  for- 
wards a  step  or  two,  each  time  anything  is 
wanted  from  the  cabinet,  will  amount  to  a  good 
deal  in  the  course  of  a  day. 

Cleanliness 

Cleanliness  is  a  matter  that  calls  for  most 
careful  consideration.  There  are  two  sorts  of 
cleanliness,  real  and  apparent,  and  both  are 
necessary.  A  tarnished  or  even  rusty  instru- 
ment, just  sterilized,  is  actually  cleaner,  in  the 
surgical  sense,  and  safer  to  use  than  one  that  is 
bright,  but  has  only  been  polished  in  the  ordi-  , 
nary  household  way ;  nevertheless  out  of  re- 
spect to  the  patient's  feelmgs,  everything  ought 
to  look  as  bright  and  clean  as  possible  ;  many  a 
dentist  allows  his  appliances  to  get  into  a  con- 
dition that  an  ordinary  housekeeper  would  be 
ashamed  to  see. 

While  a  bright  and  cleanly  appearance  is 
most  deshable,  the  all-important  matter  is  the 
real  or  "  surgical  "  cleanliness.  Before  gomg 
into  details  as  to  the  way  in  which  this  may  be 
secured,  it  wUl  be  necessary  to  understand 
clearly  the  nature  of  the  problem  that  the  dental 
surgeon  has  to  face,  and  the  limitations  that 
are  imposed  on  him  by  the  conditions  under 
which  he  is  working. 

In  the  course  of  a  day's  work  a  busy  dental 
surgeon  will  see  and  treat  a  number  of  different 
cases,  and  will  be  at  work  pretty  continuously 
for  several  hours  at  a  stretch.  Some  of  these 
cases  are  almost  certain  to  be  purulent ;  he 
may  have  to  extract  an  abscessed  tooth,  or  , 
perform  a  scaling  for  a  patient  ^\ith  septic  | 
gingivitis,  and  every  day  he  will  be  treating 
ordinary  septic  dead  teeth.  From  these  patients 
there  will  be  projected  from  time  to  time  bits 
of  tartar,  tooth  shavings,  or  droplets  of  saliva, 
blood,  or  pus,  some  large  enough  to  be  visible, 
but  the  greater  number  of  microscopic  size. 
These  ■rtU  settle  in  various  places  according 
to  their  size  and  the  directions  of  the  air  cur- 
rents they  may  meet  with.  Many  will  come 
to  rest  on  the  clothes  of  operator  and  patient, 
others  on  the  cliaii-,  bracket  table,  and  cabinet, 
still  more  on  the  floor;  the  finest  ones  wiD 
eventually  settle  on  the  walls,  curtains,  and 
in  fact  in  any  place  where  dust  can  collect. 

Many  of  these  particles  are  loaded  with  pus- 
producing  bacteria,  but  they  are  not  the  only 


source  of  danger,  as  many  otlier  pathogenic 
organisms  are  occasional  denizens  of  the  mouth. 
It  is  a  well-kno\^Ti  fact  that  people  apparently 
in  perfect  health  maybe  "  carriers  "  of  infection. 
Scarlet  fever  and  diphtlieria  are  of  especial 
interest  in  this  connection,  because  the  organisms 
which  cause  them  may  lurk  about  a  patient's 
throat  long  after  he  has  recovered  from  his 
actual  illness.  At  any  time  a  i^atient  suffering 
from  sjrphilis  may  present  himself  for  dental 
treatment ;  fortunately  most  dental  surgeons 
would  be  able  to  recognize  the  manifestations 
of  this  disease,  and  w^ould  be  on  their  guard 
against  it. 

From  the  fact  that  a  patient  carries  patho- 
genic organisms  in  his  own  mouth,  it  is  obvious 
that  really  "  aseptic  "  dental  surgery  is  not 
possible,  and  fortunately  the  oral  mucous 
membrane  seems  to  possess  an  extraordinary 
power  of  resistance  to  infection.  On  the  other 
hand  there  is  one  thing  that  the  dentist  can 
and  must  do,  and  that  is  to  prevent  the  carrying 
of  uifection  from  one  patient  to  another.  This 
is  part  of  the  problem  that  is  continually  pre- 
senting itself  to  the  general  surgeon,  and  it  will 
be  instructive  to  consider  what  measures  he 
takes  to  prevent  access  of  infective  material  to 
his  operation  wounds. 

If  the  operating  theatre  of  a  hospital  is  visited, 
it  will  be  noticed  that  the  precautions  taken 
may  be  classified  in  four  groups  :  those  relating 
to  the  fittings,  the  instruments,  the  surgeon,  and 
the  patient. 

Without  going  too  much  into  detail  it  may 
be  said  tliat  the  theatre  floor,  walls,  tables,  and 
aU  fittings  generally,  are  made  of  very  easily 
cleansed  substances,  such  as  tiles,  glass,  or  enam- 
elled iron ;  there  are  no  corners,  crevices,  or 
mouldings  to  catch  dust,  and  everything  in  the 
way  of  curtainis,  drapery,  and  upholstering  is 
absent.  Instruments  are  sterOized  by  boiling, 
and  are  then  placed  in  trays  of  antiseptic  fluid 
to  be  taken  thence  as  the  surgeon  requires  them. 
It  is  an  education  in  itself  to  watch  the  elaborate 
cleansing  of  the  surgeon's  hands,  and  the  don- 
ning of  overalls,  and  perhaps  cap  and  mask  as 
well. 

Theoretically,  nothing  would  be  easier  than 
to  sketch  out  an  ideal  set  of  arrangements  and 
rules  for  dental  practice  on  these  lines,  but  it 
must  be  remembered  that  the  conditions  of 
dental  practice  are  widely  different  from  those 
of  general  surgery.  A  surgeon  may  spend  half 
an  hour  or  more  prejjaring  himself  and  his 
instruments  for  one  case,  but  the  dentist  is 
obliged  to  treat  case  after  case  throughout  the 
day,  with  but  very  short  breaks  between  them. 
Hence  whatever  plan  is  proposed  must  not  take 
up  too  much  time,  or  it  will  be  dismissed  by 
the  average  man  as  a  "  counsel  of  perfection  ". 

The     scheme     suggested    in    the    following 


325 


remarks  has  at  least  the  merit  of  having  been 
put  into  actual  everyday  practice.  No  claim  is 
made  that  it  is  ideally  perfect,  as  improvements 
are  continually  being  made  in  it,  both  in  tlie 
direction  of  greater  thoroughness  and  greater 
facility. 

Furniture  ami  Fittings. — One  most  important 
prbiciple  m  cleanly  workuig,  in  the  surgical 
sense,  is,  as  we  have  seen,  the  avoidance  of 
dust ;  and  a  good  deal  may  be  done  to  miti- 
gate this  evU,  witliout  sacrificing  the  artistic 
appearance  of  tlie  room,  or  its  feeling  of 
comfortr.  One  of  the  first  things  to  be  thought 
about  is  the  floor,  and  this  sliould  not  be 
covered  with  that  worst  of  all  dust-catching 
contrivances,  a  fixed  carpet.  Wood  blocks 
form  an  almost  ideal  flooring.  These  are  not 
always  to  be  had,  but  there  are  several  ex- 
cellent substitutes  that  answer  the  purpose 
just  as  well,  such  as  a  veneer  of  small  boards 
J-inch  thick,  carefully  fitted  together,  m  orna- 
mental patterns,  on  the  top  of  the  existing 
deal  floor,  and  subsequently  well  polished. 
Simpler  still  are  inlaid  Unoleum  and  cork  carpets, 
which  are  made  in  colours  and  patterns  hardly 
distinguishable  from  parquet  flooring  itself. 
All  these  materials  can  be  cleaned  as  frequently 
and  as  thoroughly  as  one  may  wish.  A  thin 
rubber  mat  at  the  chair  will  be  comfortable 
to  stand  on,  and  will  prevent  any  possible 
slipping  of  the  operator's  feet,  or  of  the  foot- 
switch  of  the  electric  engine.  One  or  two  rugs 
on  the  floor  will  give  an  appearance  of  comfort, 
and  as  they  can  be  taken  out  into  the  air  every 
day  and  well  shaken,  they  will  be  practically 
unobjectionable  from  the  hygienic  point  of  view. 
Although  dust  can  be  reduced  to  a  mmimum, 
the  actual  floor  surface  is  bound  to  be  unclean ; 
and  it  should  be  made  an  absolute  rule  that 
whatever  falls  on  the  floor  should  go  at  once 
either  into  the  sterilizer  or  the  waste-container. 

It  is  as  well  to  avoid  wall  coverings  that 
have  patterns  m  strong  relief ;  smooth  materials, 
such  as  "  duresco ",  or  flat-varnished  paper, 
not  shiny,  are  clean,  and  also  lend  themselves 
to  artistic  treatment.  Curtains  and  drapery 
should  be  dispensed  with  as  far  as  possible ; 
it  is  best  to  have  none  at  all,  but  whatever 
there  are  should  be  frequently  clianged.  For 
chairs  and  couches  leather  or  removable  covers 
are  perhaps  the  best,  and  plush  about  the  worst 
that  can  be  imagined ;  this  also  applies  to  the 
operating  chair  itself  ;  its  left  arm-rest  in  parti- 
cular is  in  continual  danger  of  being  soiled  by 
drops  that  escape  the  spittoon.  A  great  im- 
provement will  be  made  by  substituting  rubber 
for  the  carpet  with  which  the  foot-rest  is  gener- 
ally covered. 

The  bracket-table  should  be  as  simple  as 
possible  ;  the  best  of  all  is  a  plain  sheet  of  glass 
with  a  removable  metal  rim,  so  that  the  whole 


arrangement  can  be  easily  and  quickly  sponged 
after  each  case.  This  Ls  very  necessary  because 
the  table  is  just  in  the  position  to  catch  a  good 
deal  of  contamination ;  for  this  reason  it  is  well 
to  avoid  a  table  with  drawers,  as  they  are  more 
likely  still  to  catch  dht,  and  increase  the  diffi- 
culty of  cleansuig  tenfold ;  in  fact  it  is  fairly 
safe  to  say  they  are  never  clean  at  all. 

The  cotton-ivool  and  waste  holders  deserve 
some  little  attention.  It  hardly  seems  the  best 
plan  to  have  the  day's  supply  of  wool  on  the 
bracket  table,  where  it  will  be  sure  to  get  fouled 
by  contact  with  soiled  fingers.  A  better  plan 
is  to  take  a  little  fresh  supply  for  each  case, 
an  orduiary  wool  roll  formmg  a  most  convenient 
source  from  which  to  take  small  portions  for 
the  various  needs  that  are  continually  aris- 
ing. Whatever  may  be  said  in  favour  of  the 
wool-holder,  there  is  no  doubt  that  most 
'  waste-receivers  are  objectionable  m  the  extreme, 
inasmuch  as  the  tweezers  are  freed  from  the 
piece  of  wool  sticking  to  them,  by  scraping  them 
along  the  slot  in  the  top  of  the  receiver,  which 
is  already  fouled  by  the  material  from  the  last 
case.  Fortunately,  there  is  now  a  perfectly 
satisfactory,  simple,  and  cheap  device  for  this 
purpose  in  the  shape  of  little  cardboard  waste- 
holders  made  by  some  of  the  supply  houses ;  a 
fresh  one  is  used  for  each  case  and  thrown  away 
when  soiled. 

Of  the  various  kinds  of  spittoon  the  liest  is 
some  variety  of  the  fountain  bowl,  with  constant 
water  supply.  In  fitting  the  fountain  spittoon 
there  must  be  a  good  downfall  for  the  waste- 
pipe,  which  sliould  be  of  large  size.  The  bowl 
and  pipe  should  be  periodically  flushed  out  with 
strong  soda  and  water.  If  hand  spittoons  are 
used,  they  should  be  frequently  changed,  and 
well  cleaned,  and  before  being  used  again  should 
have  placed  in  them  a  small  quantity  of  some 
disinfectant  fluid. 

A  most  important  article  of  furniture  is  the 
instriiment  cabinet.  Of  these  there  can  be 
nothing  better  and  cleaner  than  the  enamelled 
iron  and  glass  cabinets  now  supplied.  The 
chief  objection  to  tliem  is  their  obtrusive  appear- 
ance, which  of  course  can  be  easily  altered,  as 
coloured  enamel  is  just  as  clean  as  wliite.  The 
use  of  formalin,  or  ratlier  of  its  solid  polymer, 
paraform,  has  made  it  possible  to  keep  a  ^^•ooden 
cabinet  hi  as  clean  a  condition,  from  the  sur- 
gical point  of  view,  as  a  metal  one.  If  a  few 
tablets  of  paraform  are  placed  in  each  drawer, 
and  an  ounce  or  so  in  the  space  underneath  the 
lowest  one,  the  air  in  the  cabinet  will  be  kept 
continuously  charged  with  formaldehyde  gas ; 
there  should  be  a  fairly  strong  odour  of  formalin 
every  time  a  drawer  is  opened,  and  they  should 
be  kept  shut,  when  not  actually  in  use,  so  that 
the  strength  of  the  antiseptic  vapour  may  be 
kept  up  to  its  proper  level.     Experiment  has 


326 


shown  that  no  cultivations  can  be  made  from 
dust  taken  from  a  closed  space  in  which  para- 
form  has  been  kept  for  some  hours.  Tliis 
method  of  keeping  sterile  is  equally  applicable 
to  metal  cabinets,  or  any  other  kind  of  closed 
receptacle  whatever.  If  a  wooden  cabinet  is 
used  it  is  an  excellent  plan  to  have  the  drawers 
lined  with  glass ;  the  same  purpose  will  be  an- 
swered by  the  movable  porcelain  trays  now 
supplied,  or  by  having  detachable  linings  of 
enamelled  iron.  By  the  side  of  the  cabinet 
is  usually  the  most  convenient  place  for  the 
table  on  which  the  sterilizer  is  kept,  so  as  to  be 
within  easy  reach  of  the  operator.  The  metal 
tables  supplied  by  the  manufacturers  are 
admirably  suited  for  this  purpose.  It  is  better 
however,  to  have  marble  or  slate  for  the  top 
and  shelf,  in  place  of  glass,  which  is  liable  to 
be  cracked  by  the  heat  of  the  sterilizer. 

histruments. — The  care  of  the  instruments 
may  now  be  considered.  This  is  the  most  im- 
portant of  all  because,  whatever  may  be  the  ulti- 
mate source  of  infection,  it  is  usually  conveyed 
to  the  patient  by  an  instrument  of  some  kind. 

By  far  the  most  convenient  and  most  gener- 
ally satisfactory  method  of  sterilization  is  by 
boUing ;  hence  the  sterilizer  is  one  of  the  most 
important  pieces  of  apparatus  in  the  room. 
The  oblong  shape,  wliich  allows  instruments 
of  the  largest  size  to  be  quite  submerged  in  the 
boiling  fluid,  is  preferable  to  the  "pot"  shajae, 
which  only  allows  the  points  to  be  covered. 
Gas  and  electricity  are  equally  useful  as  sources 
of  heat.  The  addition  of  sodium  carbonate 
(ordinary  washing  soda)  to  the  water  both  ren- 
ders the  sterilization  more  rapid  and  prevents 
the  tarnishing  of  steel  instruments ;  as  a  matter 
of  fact  individual  instruments  have  been  boiled 
hundreds  of  times  in  the  course  of  a  year  or  two 
without  being  deteriorated  in  any  way  whatever. 
This  is  the  case  with  almost  all  articles  made  of 
metal,  with  the  exception  of  aluminium.  Many 
things  not  made  of  metal  \\ill  stand  repeated 
boiling  ;  materials  that  will  not,  such  as  cellu- 
loid, had  better  be  avoided  in  the  construction 
of  dental  instruments. 

Directly  the  patient  is  out  of  the  chair,  all  in- 
struments, with  a  few  exceptions  to  be  mentioned 
later,  should  be  collected  together  and  placed 
in  the  sterilizer,  and  the  table  sponged  with 
an  antiseptic.  Wliile  the  next  patient  is  being 
seen,  the  surgery  attendant,  who  for  this  p\irpose 
need  be  no  more  than  the  servant  who  opens 
the  door,  can  take  the  in.struments  out,  dry 
them,  and  return  them  to  their  places. 

There  are  certain  instruments  that  it  is 
either  impo.s.sible  or  inconvenient  to  boil,  and 
these  must  be  treated  in  some  other  way ;  these 
exceptions  had  better  be  discussed  in  detail. 

Gold- filling  instruments,  inasmuch  as  they 
never   touch   anything   wet,   will    hardly   need 


further  care  than  keeping  in  a  closed  drawer 
with  some  paraform ;  this  does  not  apply  to 
files  and  trimmers,  which  are  sometimes  used 
after  the  rubber  is  taken  off. 

Burrs,  nerve  instruments,  and  such-like  very 
small  articles,  can  be  boiled  with  the  rest  or 
treated  by  being  placed  in  2  "J,  lysol  or  lysoform 
directly  after  use,  and  allowed  to  remain  there 
until  the  next  day,  when  tliey  may  be  brushed 
and  dried.  This  method  involves  the  keeping 
of  more  of  these  instruments  in  use  than  some 
other  methods  do,  but  it  is  not  less  economical, 
as  tlie  instruments  are  not  actually  used  more 
in  the  long  run. 

Lysol,  owing  to  its  alkaline  reaction,  possesses 
the  great  advantage  that  steel  and  nickel-plated 
articles  can  be  kept  in  it  for  an  indefinite  time, 
without  appreciable  rusting  or  tarnishing.  This 
method  of  keeping  is  particularly  convenient  for 
two  classes  of  instruments,  namely 

(1)  Forceps  :  these  should  always  be   boiled 

after  use,  and  then  placed  in  the  anti- 
septic ;  they  are  then  ready  for  use 
at  a  moment's  notice.  Otherwise  they 
ought  certainly  to  be  boiled  immediately 
before  using,  and  this  takes  up  valuable 
time.  Convenient  shallow  glass  dishes, 
with  glass  or  metal  tops,  are  supplied 
in  various  sizes,  and  will  be  found  most 
useful  for  this  purpose. 

(2)  Hand-pieces  :  these  are  often  liable  to  get 

very  much  soiled.  A  convenient  plan 
is  to  have  two  or  more  of  these  in 
use,  and  to  take  them  in  rotation ; 
when  not  actually  being  used,  they 
should  rest  in  lysol ;  this  will  ensure 
their  being  at  least  moderately  clean 
when  their  turn  comes  to  be  taken 
out.  This  treatment,  moreover,  keeps 
them  in  excellent  working  order.  Some 
makers  are  suppljang  right-angle  at- 
tachments with  detachable  heads,  which 
can  be  boiled,  but  even  then  the  handle 
part  should  be  kept  immersed  in  anti- 
septic. 

The  hypodermic  syringe,  if  septic,  is  perhaps 
the  most  dangerous  carrier  of  infection  in  the 
dental  surgeon's  outfit.  Both  all-metal  and 
all-glass  and  also  combination  glass  and  metal 
sjrringes  are  made.  These  can  be  sterilized  by 
boiling,  with  the  exception  of  the  glass,  which 
can  be  cleaned  with  carbolic  or  other  antiseptic. 
If  a  fresh  quantity  of  solution  is  required  for 
the  same  case,  a  new  needle  should  be  fixed 
before  refilling  the  syringe ;  this  wall  prevent 
the  inside  from  getting  soiled  by  septic  matter 
being  drawTi  into  the  barrel. 

Mirrors  have  hitherto  been  difficult  to  ster- 
ilize, but  the  difficulty  has  been  greatly  dimin- 
ished by  the  use  of  cone-socket    handles ;    the 


327 


handle  can  be  unscrewed  and  boiled  after  each 
case,  and  the  glass  placed  in  some  antiseptic 
solution ;  three  or  four  glasses  should  be  kept 
and  used  in  rotation. 

Anaesthetic  apparatus  is  more  difficult  still. 
The  masks  should  be  most  carefully  cleansed 
with  antiseptic  solution,  and  the  rubber  face- 
pad  taken  off  and  boiled.  The  ga.s  stopcock 
frequently  does  not  get  the  attention  it  deserves  ; 
Vernon  Knowles  has  designed  one  made  entirely 
of  metal,  which  can  be  boiled  witliout  injury 
to  any  of  its  parts.  The  gas-bag  is  not  likely 
to  get  fouled,  unless  "  re-breathing  "  is  prac- 
tised. If  this  is  the  case  the  bag  ought  certainly 
to  be  well  cleansed,  and  bags  are  supplied  that 
can  be  turned  inside  out  for  this  purpose. 

Trays  are  easily  sterilized  by  boiling ;  com- 
position should  be  new  for  each  patient,  unless 
it  has  been  kept  for  an  hour  and  a  half  at  boiling- 
water  temperature,  as  Kenneth  Goadby  suggests. 

Napkins  should  be  of  a  material  that  can 
be  tlirown  away  after  use,  or  else  well  boiled 
after  each  case. 

Rvbher-dam  may  quite  well  be  used  again  if 
ihorougJily  sterilized ;  in  fact,  as  J.  H.  Badcock 
has  pointed  out,  it  is  then  jirobably  much 
cleaner  than  when  it  comes  from  the  factory ; 
this  is  the  case  with  many  other  things,  as  factory 
workmen  camiot  be  expected  to  have  much 
idea  of  surgical  cleanliness. 

The  water-syringe  is  certain  to  get  fouled, 
either  from  the  patient's  mouth  or  the  operator's 
fingers ;  all-metal  syringes,  which  can  no\\'  be 
obtained,  cause  no  difficulty;  if  one  with  a 
leather  washer  is  used,  the  piston  part  can  be 
soaked  in  antiseptic  fluid  ^^•hiIe  the  barrel  is 
being  boiled. 

As  is  the  case  in  general  surgery,  certain  pre- 
cautions in  connection  with  the  operator's 
person  and  methods  are  essential.  While  at 
work  the  dentist  should  wear  a  coat  made  of 
some  light  washable  material.  The  care  of  the 
hands  is  quite  a  serious  problem.  The  dental 
surgeon  has  to  clean  his  hands  so  many  times 
in  the  day  that  the  metliods  used  by  the  general 
surgeon  are  inadvisable  on  account  of  their 
destructive  action  on  the  skin ;  they  are,  be- 
sides, unnecessary.  The  ^^■ash-basin  sliould  be 
conveniently  close  to  the  chair,  and  if  possible 
fitted  with  taps  operated  by  foot-pedals.  The 
ordinary  nail-brush,  kept  in  the  open,  is  little 
better  than  a  germ  trap,  as  bacteriological 
examination  has   shown  that  there  are  often 


more  organisms  on  the  hands  after  its  use  than 
before.  This  is  not  the  case  \\-ith  a  brush  kept 
in  an  antiseptic  fluid,  and  brush-containers  are 
made  by  the  surgical-instrument  makers  for 
this  purpose.  Lysol  is  one  of  the  best  fluids  to 
keep  the  brush  in,  and  is  sufficiently  antiseptic 
in  a  strength  that  does  not  injure  the  skin.  The 
chief  objection  to  lysol  is  its  odour,  but  this  can 
be  masked  by  dipping  the  hands  into  a  bowl  of 
glycerine  and  rose-water  after  lirushing  them 
with  the  lysol.  This  treatment  may  be  repeated 
almost  any  number  of  times  a  day  \\-ithout 
injury,  in  fact  it  will  keep  the  hands  in  excellent 
condition. 

WHiile  operating  it  is  well  not  to  allow  the 
.soiled  fingers  to  touch  one's  face  or  clothes, 
or  anjrthing  else  beyond  the  actual  work  in 
hand.  Especial  care  should  be  taken  to  avoid 
contamination  of  the  instrument  cabinet  from 
this  source.  It  is  quite  easy  to  open  the  trays, 
especially  of  metal  cabinets,  and  take  instru- 
ments from  them  with  a  pair  of  stout  straight 
tweezers  similar  to  those  used  in  the  laboratory 
for  soldering.  As  far  as  possible,  the  instru- 
ments required  should  all  be  taken  from  their 
places  before  the  operation  is  begun.  For  the 
operator's  own  sake,  the  use  of  the  chip-blower 
should  be  avoided  except  for  the  necessary 
drying  of  cavities ;  yet  one  often  sees  a  cloud 
of  what  must  be  intensely  septic  dust  thrown 
out  into  the  aii-  that  both  patient  and  operator 
are  breathing  all  the  time. 

Many  other  details  will  suggest  themselves, 
but  the  main  principles  of  surgical  cleanliness 
have  now  been  indicated.  Perfection  has  cer- 
tainly not  been  attained,  but  improvements 
are  constantly  being  made,  and  the  A\liole 
practice  of  dental  surgery  is  in  process  of  evolu- 
tion towards  better  hygienic  conditions. 

J.  B.  P. 

BIBLIOGRAPHY 

(1)  Badcock,     J.     H.      Brit.     Dent.     Jour.,     IQOU, 

Vol.  XXVII,  p.  433. 

(2)  Black,  G.  V.     Operative  Dentistry.  Vol.  I,  p.  172. 

(3)  Law,  W.  J.     Brit.  Dent.  Jour.,  1906,  Vol.  XXVII, 

p.  394. 

(4)  Ottolengui,  R.   jDentai  Cosmo*,  1905,  Vol.  XLVII, 

p.  388. 

(5)  VoYLES,  S.  H.    Dental  Cosmos,  Dec.  1909,  Vol.  LI 

p.  1408. 

(6)  Webster,   A.   E.     Johnson's  Operative  Dentistry, 

pp.  85,  ff. 

(7)  Webster,     .1.     Forbes.      Dental    Record,     1909, 

Vol.  XXIX,  p.  214. 


CHAPTER  XVIII 


ORAL   HYGIENE   AND   PREVENTIVE   TREATMENT   OF   DENTAL 

CARIES 


It  has  been  truly  said  that  "  tlic  mouth  is 
the  vestibule  of  life  ",  and  therefore  it  behoves 
dental  surgeons,  as  the  potential  guardians  of 
that  important  cavity  and  its  contents,  to  take 
every  possible  means  to  keep  its  various  func- 
tions in  as  thorough  working  order  as  possible. 
It  may  be  noted  that  every  piece  of  food  pass- 
ing into  the  stomach,  and  part  of  the  air 
breathed  into  the  lungs,  fu-st  passes  through 
the  mouth,  and  therefore  neither  should  have 
normally  any  chance  of  becoming  contaminated. 
The  two  main  objects  in  oral  hygiene  and 
prophylaxis  as  practised  in  the  mouth  are, 
firstly,  to  jsrevent  oral  sepsis  and  its  many 
sequelae ;  and  secondly,  to  prevent  dental  caries 
and  consequent  destruction  of  the  masticating 
power  of  the  mdividual. 

The  evils  of  oral  sepsis  are  very  frequently 
met  with  and  are  often  serious.  But  the  resist- 
ing and  recuperative  po^\'ers  of  the  mucous 
membrane  of  the  mouth  often  act  as  a  barrier, 
and  are  important  factors  in  the  prevention 
of  grave  results.  The  mouth  itself  is  the 
normal  habitat  of  a  very  large  number  of 
different  micro-organisms,  and,  on  account  of 
its  situation  and  functions,  it  must  necessarily 
be  very  frequently  contaminated  with  patho- 
genic bacteria,  which,  in  a  suitable  nidus, 
wOl  cause  serious  trouble ;  and  it  is  perfectly 
justifiable  to  expect  that  on  the  slightest 
lowering  of  the  Natality  of  the  individual  his 
tissues  will  become  immediately  invaded  by 
the  micro-organisms  present  in  his  moutli, 
and  some  form  of  disease  be  brought  about. 
And  again,  the  arrangement  of  the  teeth  and 
gums  is  often  such  that,  unless  certain  pre- 
cautions are  taken  to  prevent  it,  micro-organisms 
will  be  readily  harboured  and  allowed  to  propa- 
gate in  the  very  situation  that  is  most  suitable 
for  their  existence.  Neglect  of  the  teeth  and 
gums  is  a  most  frequent  source  of  trouble.  If 
food  is  left  undisturbed  in  crevices  and  inter- 
stitial spaces,  it  Mill  readily  ferment  or  jnitrefy 
according  to  its  composition,  and  thereby  the 
soft  tissues  N\'ill  be  irritated  or  the  teeth  them- 
selves destroyed;  and  it  axtII  generally  be 
observed,  in  the  mouths  of  those  N^ho  take  no 
precautionary  measures  to  prevent  tlie  harbour- 
ing of  foreign  matter,  that  there  is  gingivitis 
present  in  greater  or  less  degree. 


The  above  conditions,  then,  constitute  oral 
sepsis,  and  may  affect  the  patient  in  many  ways. 
By  direct  septic  infection  of  neighbouring  tissues, 
general  gingivitis,  stomatitis,  trouble  m  the 
maxillary  sinus,  necrosis,  cellulitis  of  the  tissues 
of  the  cheek  or  neck,  may  all  be  brought  about. 
By  remote  septic  infection,  the  lymphatic  glands, 
the  stomach,  the  intestines,  and  lungs,  may 
severally  be  affected  ;  and  from  septic  absorption, 
either  septicaemia,  pyaemia,  septic  anaemia, 
septic  neuritis,  septic  pleurisy,  septic  nephritis, 
or  puerperal  fever,  may  supervene.  All  tliese 
are  the  residt  of  pyogenic  infection.  (See 
Chapter  XLVI.)  The  conditions  most  necessary 
for  pyogenic  infection  are — (a)  an  abrasion 
of  the  mucous  membrane,  (b)  lowered  vitality 
from  any  cause,  and  hence  diminished  resist- 
ance of  the  tissues,  and  (c)  continuous  expo- 
sure to  the  doses  of  infection  (11).  These  are 
exactly  the  conditions  so  frequently  found 
in  a  septic  mouth,  and  therefore  constitute 
the  reason  why  oral  sepsis  so  often  leads  to 
general  pyogenic  infection.  It  is,  therefore,  of 
the  gravest  importance  that  the  mouth,  which 
can  be  so  easily  treated,  should  be  continually 
tended,  and  hygienic  measures  taken  to  pre- 
vent it  becoming  the  source  of  uifection.  The 
opinion  is  strongly  upheld  (II)  that  if  oral  sepsis 
could  be  overcome  the  other  chamiels  by  which 
"  medical  sepsis  "  gains  entrance  might  be  left 
to  chance. 

It  is  seen  from  the  above  that  the  import- 
ance of  prophylactic  measures  cannot  well  be 
over-estimated  ;  and  ajjart  from  the  individual, 
there  are  few  problems  of  greater  public  import- 
ance than  the  hygiene  of  the  mouth.  The  gospel 
of  the  clean  mouth  and  clean  teeth  shoidd  be  for 
ever  preached,  for  "  the  influence  of  the  training 
of  the  patient  in  the  proper  care  of  the  mouth 
wUl  be  productive  of  much  good  to  the 
teeth  and  general  health  of  generations  to 
come "  (16).  Absolute  cleanliness,  therefore, 
should  be  the  watchword;  but  as  absolute 
cleanliness  is  probably  impossible  of  attainment, 
the  nearest  approximation  to  it  must  be  aimed 
at.  The  reports  of  the  Diamond  Match  Factories 
in  the  United  States  make  interesting  reading 
in  this  connection.  Great  care  and  supervision 
is  taken  with  the  teeth  of  all  employees ;  each 
individual  lias  a  three-monthly  inspection,  all 


328 


329 


teeth  are  scaled  and  filled  when  necessary,  and 
oral  hygiene  is  attended  to,  every  patient  being 
carefully  charted.  In  comparing  the  condition 
of  the  employees  since  these  measures  ^^'ere 
adopted,  with  that  formerly  obtaming,  the 
following  observations  were  made — (a)  much 
less  caries,  {b)  the  gums  all  healthy  and  pink  i 
in  colour,  (c)  fewer  days  lost  through  illness, 
and  (d)  much  better  general  health. 

The  means  of  attaining  the  desired  result  of 
a  clean  mouth  and  clean  teeth  may  be  broadly 
indicated  under  two  headings — (a)  by  natural 
means,  that  is,  by  proper  mastication  of  a 
rational  diet ;  and  (b)  by  artificial  means,  that 
is,  by  hygienic,  chemical,  and  bacteriological 
methods. 

Natural  Means  of  Cleansing. — -The  beautiful 
conformity  and  arrangement  of  a  normal  den- 
tition indicate  that  the  teeth  were  intended  to 
be  of  great  service  to  the  individual ;  but  the 
advance  in  civilization,  and  with  it  the  culinary 
art,  has  lessened  their  use  ;  hence  the  food  tends 
to  cling  about  the  mouth,  and  tartar  to  collect, 
and  the  necessity  for  artificial  means  almost 
invariably  arises.  But  if  it  were  possible  to 
return  to  a  dietary  that  necessitated  vigorous 
mastication,  the  surfaces  of  the  teeth  would  be 
continually  polished  by  the  friction  of  the  food,  ■ 
and  the  gums  stimulated  to  their  proper  func- 
tion, and  thus  the  integrity  and  environment 
of  the  teeth  maintained  in  their  normal  con- 
ditions. There  would  then  be  less  dental  caries 
and  fewer  diseases  of  the  soft  tissues  of  the 
mouth.  Sim  Wallace  (25)  sums  the  whole 
c^uestion  up  in  the  following  words  :  "  If  children 
are  fed  accordmg  to  physiological  principles, 
Awhile  hygiene  requirements  are  not  neglected, 
the  teeth  will  not  decay,  nor  wiU  the  other 
diseases  which  result  from  the  infringement 
of  physiological  laws  be  at  aU  likely  to  be 
prevalent."  A  diet  that  will  teach  the  child 
how  to  masticate  is  the  surest  means  of  preven- 
tion of  caries,  for  not  only  will  the  teeth  be 
properly  cleansed,  but  the  jaws,  being  efficiently 
used,  ^^ill  develop  to  their  fullest  extent,  and  the 
possibility  of  irregularity  in  position  of  the 
teeth,  and  therefore  predisposition  to  caries,  be 
reduced  to  a  minimum.     (See  Chapter  XIII.)      I 

The  method  adopted  in  the  early  rearing  of 
the  uifant  is  of  considerable  importance  from 
the  point  of  view  of  prophylaxis  of  dental  caries. 
There  is  considerable  evidence  to  support  the 
contention  that  breast-fed  children  are  less 
liable  to  caries  than  artificially  fed  children, 
probably  on  account  of  a  larger  percentage  of 
lime  salts  in  their  teeth.  Cow's  milk,  besides 
being  "  humanized  ",  should  therefore  receive 
an  addition  of  lime-water;  and  patent  foods 
should  be  avoided.  And  again,  a  wholly  hygienic 
mode  of  liv^ing  will  lessen  the  tendency  to  rickets 
and  fevers  in  the  infant,  and  tliereby  reduce  to  a  \ 
11* 


minimum  the  risk  of  hypoplasia  of  the  teeth  and 
their  consequent  predisposition  to  caries. 

From  about  nine  months  of  age  the  mfant 
can  be  given  a  little  solid  food,  such  as  bread 
or  toast  with  butter,  from  A\"hich  he  can  gnaw 
and  suck  as  from  tlie  breast ;  the  thorough 
insalivation  and  liquefaction  of  the  bread, 
brought  about  by  the  sucking,  renders  it  per- 
fectly digestible  on  jjassing  into  the  stomach. 
This  can  be  increased  up  to  about  twelve  months, 
and  then,  with  the  advent  of  the  first  deciduous 
molar  teeth,  toast  and  milk-pudding  can  be 
given  as  a  meal,  and  not  merely  as  a  small 
adjunct  to  the  breast ;  and  by  the  time  the 
second  deciduous  molars  are  in  place  boiled  fish 
or  other  simple  albuminous  food  can  be  given, 
as  the  mouth  then  possesses  its  full  function  (26). 

From  this  time  onwards  the  diet  naturally 
becomes  more  varied,  but  tliere  are  certain 
articles  of  food  that  are  especially  deleterious 
and  should  be  avoided,  or  at  least  eaten  in  such 
a  way  that  they  become  a  lesser  latent  source 
of  harm.  The  most  important  is  the  sticky 
carbo-hydrate  food,  from  which  all  fibrous 
material  has  been  eliminated,  and  which  has, 
therefore,  no  cleansing  properties,  but  only 
tends  to  cling  about  the  teeth  and  gums  and  be 
fermented  in  situ  on  the  teeth  into  lactic  acid, 
etc.  It  is  well  recognized  that  roUer-miUed 
flour,  which  has  almost  entirely  displaced 
stone-milled  flour  during  the  last  thirty  years  or 
so,  is  very  much  more  easily  fermented  into 
acid  in  the  mouth  than  its  predecessor,  and  not 
only  that,  but  tends  more  to  cling  than  the  stone- 
milled  flour,  which  contains  a  certain  proportion 
of  the  fibrous  husk  of  the  grain  (21  )i  Therefore 
the  white  loaf,  ^^•hose  falsely  praised  whiteness 
indicates  the  use  of  roller-milled  flour,  should 
be  avoided,  and  the  bread  made  from  stone- 
miUed  or  whole-meal  flour  exclusively  used. 
Sugar  and  sweets,  although  rapidly  fermentable 
into  acids  in  the  mouth,  if  taken  in  moderation 
^^■ill  do  no  harm,  as  they  are  generally  easily 
dissolved  and  washed  away.  But  the  more 
sticky  forms,  especially  if  very  frequently 
eaten,  may  greatly  aid  the  destruction  of  the 
teeth  by  caries ;  if  taken  at  all  they  should  as 
far  as  possible  be  taken  during  and  not  bet-\\een 
meals.  Medicines  containing  free  mineral  acids, 
although  easily  washed  away,  should,  never- 
theless, be  taken  in  such  a  way  as  not  to  be 
allowed  to  flow  about  the  teeth,  or  the  mouth 
should  be  freely  rinsed  after  their  use,  in  order 
to  minimize  the  risk  of  decalcification.  The  acid 
in  fruit  which  is  masticated  stimulates  a  flow  of 
alkaline  saliva;  this  acts  probably  as  a  neutral- 
izing agent,  and  no  harm  results. 

It  is  difficult  definitely  to  outline  a  typical 
meal,  as  the  age  and  taste  naturaUj'  pl^J  so  large 
a  part  in  eating ;  but  it  may  be  pointed  out  that 
the    sticky   carbo-hj'drates    mentioned    above, 


330 


namely,  bread,  biscuits,  thick  sugary  articles, 
etc.,  should  always  be  taken  at  the  beginning  or 
middle  and  never  at  tlie  end  of  a  meal,  which 
should  be  finished  with  food  of  a  cleansing  nature 
such  as  fresh  fruit.  Sim  Wallace  (27)  suggests 
the  following  as  a  tj^ical  meal  for  a  child — 

Breakfast. — Fish,  bacon,  toast  and  butter, 
coffee  or  tea. 

Luncheon. — Meat  or  poultry,  potatoes,  salad, 
well-baked  milk-pudding,  fresh  fruit,  water. 

Supper. — Rusks,  toast  or  bread-rolls  and 
butter,  chicken  or  fish,  water,  milk-and-water 
or  tea,  fresh  fruit. 

Whatever  the  solid  food,  however,  it  should 
always  be  followed  by  liquid  of  some  sort  as 
the  last  ingiedient  of  a  meal. 

The  regularity  m  the  arrangement  of  the 
teeth,  and  the  correct  occlusion,  are  important 
factors  in  the  prevention  of  food  lodgement. 
With  a  perfectly  normal  arrangement  of  the 
two  arches  the  food  is  so  worked  upon  the  teeth 
in  mastication  that  there  is  little  tendency  for 
the  food  to  lodge,  the  lips,  cheeks,  tongue,  and 
inter-proximal  papillae  of  gum,  tending  to  keep 
the  teeth  tree  from  adherent  food,  except  of 
course  the  more  sticky  carbo-hydrates,  which  will 
lodge  in  any  crevice.  It  is,  therefore,  important 
from  a  dtntal  hygienic  point  of  view,  quite 
apart  from  aesthetic  and  utilitarian  reasons, 
that  every  abnormality  in  position  of  the  teeth 
should  be  corrected,  so  as  to  make  the  arch  as 
nearlv  nornifil  as  possible. 

Artificial  Means  of  Cleansing. — The  natural 
means  of  keeping  the  mouth  in  a  hygienic  con- 
dition having  now  been  discussed,  the  artificial 
means  will  be  taken  in  detail.  As  stated  above, 
the  necessity  for  the  latter  arises  on  account  of 
the  unnatural,  but  usual,  mode  of  feeding  of 
both  children  and  adults.  In  almost  every 
text-book  or  article  on  the  subject  one  reads 
the  well-worn  sentence — "  clean  teeth  will  not 
decay " — , which  cannot  be  disputed  if  read 
literally.  It  therefore  behoves  dental  surgeons 
to  do  all  in  their  power  to  see  that  then  patients' 
teeth  are  clean.  The  ordinary  means  at  the 
patient's  disposal  for  cleansing  the  mouth  are 
tooth-brushes,  with  or  without  powders,  tooth- 
picks, floss  silk,  dragon  canes,  and  mouth  washes. 
Tooth-brushe.s. — 'The  tooth-brush  is  an  imple- 
ment that  is  frequently  abused.  Experiments 
conducted  by  Miller  (18)  conclusively  proved 
that  by  vigorous  cross-brushmg,  especially  in 
conjunction  with  powders  or  pastes,  great 
injury  was  done  to  the  teeth  in  the  form  of  so- 
caUed  erosion  cavities,  and  he  attributed  all 
erosion  cavities  to  this  cause.  The  gums  like- 
wise will  be  caused  to  recede.  Healthy  gums 
will  stand  a  considerable  amount  of  brushing 
and  will  be  benefited  by  it  if  used  in  a  judicious 
manner.  To  avoid  injury  it  is  not  sufficient, 
however,  merely  to  instruct  patients,  as  is  so 


often  done,  to  brush  the  teeth  up  and  down  as 
well  as  across ;   they  sliould  be  taught  to  make 
the   brush   rotate  against   the   surfaces  of  the 
teeth,  at  the  same  time  passing  the  bristles  as 
much  as  possible  from  the  gums  to  the  teeth 
and  not  in   the  reverse  direction,  and  to  give 
special  attention  to  the  buccal  surfaces  of  the 
third  molars,   which  are  least  accessible;    the 
occlusal  surfaces  should  be  freely  brushed  in 
all  directions.     The  size  of  the   brush  should 
be  commensurate  with  the  size  of  the  patient's 
mouth,  so  as  to  be  freely  used;   it  should,  for 
preference,   be  a  moderately  stiff  one  with  a 
serrated  edge,  whose  bristles  will  thereby  more 
readily  penetrate  between  the  teeth  than  those 
of  closely  set  brushes.     It  should  also  have  a 
lengthened  tuft  of  bristles  at  its  end  for  more 
efficiently  cleansuig  the  lingual  surfaces  of  the 
incisors ;  or,  better  still,  a  separate  brush  with 
a  tuft  only  may  be  kept  for  that  purpose.     The 
usual  times  for  brushing  the  teeth  are  night 
and  morning.     No  food  should  be  taken  after 
the   cleansing   at   night,   which   is   by  far   the 
more  important  time,  as  the  rest  and  stagnation 
in  the  mouth  during  the  sleeping  hours  give 
the  fermentative  bacteria  the  opportunity  they 
require  for  their  growth.     In  those  especially 
susceptible  to  caries,  the  teeth  should  be  brushed 
after   every    meal   and   on   retiring.     The   age 
at   which   to   start   brushing  the   teeth   is   the 
time  of  the  appearance  of  the  teeth ;  the  early 
use  of  the  brush  in  the  young  child  is  very  im- 
portant, for  not  only  will  the  few  teeth  present 
be  cleansed,  but  also  the  chUd  will  be  brought 
up  to  the  habit  and  appreciation  of  its  use. 

Patients  will  sometimes  be  encountered  with 
very  septic  mouths,  with  abundance  of  tartar, 
and  much  soft  deposit  around  the  necks  of  the 
teeth,  who  will  profess  to  clean  their  teeth  two 
or  three  times  a  day.  Under  these  circum- 
stances one  must,  as  a  rule,  discount  entirely 
any  intention  on  the  part  of  the  patients  to 
deceive,  for  almost  invariably  they  are  speaking 
I  the  truth  as  far  as  they  are  aware.  It  merely 
means  that  their  method  of  cleansing  is  wTong ; 
but  any  doubt  can  be  removed  by  requesting 
I  them  to  illustrate  their  methods.  A  definite 
demonstration  should  then  be  given  to  such 
patients  on  the  proper  hygienic  mode  of  cleans- 
ing the  mouth  and  teeth,  models  and  brushes 
being  used  if  thought  necessary. 

Floss  Silk. — It  must  be  borne  in  mind,  in 
using  the  tooth-brush,  tliat  its  bristles  wUl  not 
penetrate  between  the  teeth  to  any  appreciable 
extent,  and  therefore  if  it  is  used  alone  the  inter- 
proximal spaces,  the  most  vulnerable  spots,  re- 
mam  uncleansed.  The  best  way  to  cleanse  these 
spaces  and  remove  the  bacterial  plaques  lurking 
there  is  by  means  of  waxed  floss  silk.  The 
great  difficulty  and  discomfort  of  correctly 
using  the  silk  precludes  its  general  adoption. 


331 


but  where  patients  will  take  the  trouble  it  is 
of  extreme  utility.  It  should  be  passed  into 
every  inter-proximal  space  to  a  little  below  the 
gum,  and  then  pulled  from  the  gum  to  the  biting 
surface  with  a  light  saving  motion  against  the 
medial  and  distal  surfaces  of  every  tooth ;  if 
it  is  soaked  in  perchloride  of  mercury,  1  in  500, 
before  use,  fermentation  is  stUl  more  likely 
to  be  prevented  (7,  p.  206).  If  this  process,  in 
conjunction  «ith  brushing  and  efficient  rinsing, 
were  carried  out  thoroughly  every  day,  probably 
caries  would  cease  to  exist  in  the  mouth.  In- 
stead of  floss  silk,  thm  rubber  bands  may  be  used 
in  a  similar  manner,  but  it  is  merely  a  matter 
of  choice. 

Toothpicks. — Toothpicks  are  useful  adjuncts 
to  the  above,  especially  with  those  who  lind  a 
difficulty  in  the  use  of  the  silk,  as  they  may  be 
used  to  clear  the  plaques  from  the  inter-proximal 
spaces ;  but  they  are  more  prone  to  injure  the 
gum.  The  quUl  picks  should  be  used,  as  a  fresh 
one  can  always  be  taken,  and  they  are  much 
less  likely  to  injure  the  gum  than  a  gold  one  ; 
the  wooden  ones  tend  to  leave  splinters  in  the 
gum  and  are  more  septic. 

Dragon  Canes. — Where  the  teeth  readily 
become  discoloured  with  tobacco  smoke  or  tea 
stain,  tlie  patient  may  more  or  less  frequently 
use  a  cane,  frayed  out  at  one  end  and  cut  flat 
at  the  other,  to  rub  the  teeth  with  a  little 
powder,  using  the  flat  end  for  the  interstitial 
spaces  and  the  frayed  end  for  the  free  surfaces. 
Although  these  stams  tiiemselves  do  no  harm 
to  the  teeth  or  gums,  the  roughening  that  they 
create  increases  the  readiness  of  tartar  and  other 
deposits  to  collect. 

Tooth-powders  and  pastes. — Opinions  are 
found  to  vary  with  regard  to  the  advLsability 
of  habitually  using  tooth-powders  and  pastes ; 
they  can  be  almost  as  much  abused  as  tooth- 
brushes. The  writer  is  of  opinion  that  with 
those  whose  teeth  show  no  soft  white  deposit 
or  discoloration,  and  but  little  tartar,  the  use 
of  powders  is  superfluous,  but  otherwise  they 
are  a  necessity,  though  always  in  moderation. 
The  abrasive  effect  of  powders  and  pastes  upon 
the  teeth,  if  used  in  excess,  and  especially  if 
there  is  the  smallest  amount  of  grit  in  them, 
may  lie  very  liarmful  to  the  teeth,  as  proved 
by  Miller's  experiments  and  observations  men- 
tioned above.  Moreover,  precipitated  chalk,  of 
which  most  are  largely  composed,  if  used  in  excess, 
becomes  lodged  between  the  teeth  and  is  liable 
to  irritate  the  gum  margins,  for  it  is  insoluble 
in  the  saliva.  Tooth-powders  and  pastes  are 
mostly  used  for  their  mechanical  properties, 
but  antiseptics,  astringents,  deodorants,  etc., 
may  be  added  with  marked  benefit. 

The  following  makes  an  efficient  powder, 
which  may  be  used  with  the  brush  once  or  twice 
a  day,  as  the  necessities  of  the  case  demand,  and 


6  !]• 
5  J- 
5  ]• 
gr.  V. 
Ill  V. 
3  J- 


whose  ingredients  may  be  varied  for  reasons 
detailed  below — 

R 

Mag.  Carb.  Pond. 

Pulv.  Saponis  Dur. 

Pot.  Chlor. 

Ac.  Carbolici 

01.  Rosae.      . 

Calc.  Carb.  Precip.  ad 
M.  Fiat  pulv. 

The  heavy  carbonate  of  magnesia  is  an  antacid, 
and  may  tend  to  counteract  fermentative 
acidity ;  it  is  also  a  cleansing  agent.  The 
powdered  soap  is  also  an  antacid,  and  very 
materially  assists  the  scouring  action  and  helps 
to  dissolve  the  mucous  plaques  of  bacteria. 
For  patients  who  object  to  the  frothy  condition 
brought  about  by  the  soap  it  may  be  omitted. 
The  potassium  chlorate  is  a  slight  astringent, 
and  tends  to  counteract  any  abrasive  effect 
upon  the  gums,  and  is  especially  beneficial  if 
there  is  any  marginal  gingivitis.  If  the  gingi- 
vitis is  very  marked,  thirtj'  grams  of  tannic  acid 
may  be  substituted  for  the  potassium  chlorate. 
The  carbolic  acid  is  an  antiseptic  and  deodorant ; 
the  actual  amount  that  can  be  used  with  comfort 
in  a  tooth-powder  will  have  but  little  effect  in 
inhibiting  the  growth  of  bacteria  present,  but 
it  is  useful  in  impartuig  a  refreshing  sensation 
to  the  mouth  and  certainly  helps  to  prevent 
the  tooth-brush  from  becoming  foul.  With  a 
few  people  it  will  be  found  that  carbolic  acid 
causes  a  slight  stomatitis,  or  eczematous  con- 
dition at  the  angles  of  the  mouth,  when  it  must 
be  omitted,  and  a  similar  quantity  of  one  or 
more  of  the  essential  oils  substituted,  such  as 
the  oils  of  bergamot,  cinnamon,  cloves,  euca- 
lyptus, peppermmt,  or  wintergreen,  according 
to  the  patient's  taste  ;  or,  of  course,  one  or  more 
of  these  may  be  primarily  incorporated  in  the 
powder  instead  of  the  carbolic  acid,  if  the 
patient  so  desires  it  from  choice,  as  they  are  aU 
antiseptics,  as  well  as  powerful  flavouring  agents. 
The  otto  of  rose  is  used  principally  as  a  flavour- 
mg  agent,  it  being  only  very  slightly  antiseptic. 
The  precipitated  chalk,  which  forms  the  principal 
mgredient,  is  used  as  the  scouring  agent ;  it  is 
also  antacid. 

For  those  who  prefer  a  paste  to  a  powder  the 
following  may  be  used,  but  the  efficiency  is 
approximately  the  same — 

R 

Calc.  Carb.  Precip.        .        .  5  j. 

Pulv.  Saponis  Dur.       .        .  3  ss. 

Glycerini         .        .        .        .  3  ss. 

Thvmol gr.  iv. 

01."  Gaultheriae      .        .        .  H)  x. 

01.  Rosae        ....  Ill  j. 

Sp.  Rect q.  s. 

Misce. 


332 


In  the  above,  as  with  the  powder,  the  essential 
oils  may  be  varied  according  to  taste.  The 
thymol  is  substituted  for  carbolic  acid  as  the 
antisej)tic. 

At  no  time  should  any  grit  m  the  form  of 
powdered  cuttle-fish,  pumice,  etc.,  be  incor- 
porated m  the  tooth-powder  or  paste  for 
habitual  use. 

Where  a  powder  or  paste  seems  contra- 
indicated,  either  on  account  of  irritable  gums 
or  rooted  objection  on  the  jjart  of  the  patient, 
a  liquid  dentUrice  may  be  prescribed  for  use  with 
the  tooth-brush,  such  as — 

R 


Tr.  Quillaiae. 

, 

§ 

J- 

Tr.  Krameriae 

. 

5 

ss. 

Aq.  Cologn.  ad      . 

5 

ij- 

Fiat  dentifricium. 

isig. — "A  few  drops  to  be 

placed 

on 

a 

moLst 

tooth-brush  used 

vigorou 

sly 

5  J 

The  tincture  of  quillaia  is  a  cleansmg  agent  and 
becomes  very  frothy  m  the  mouth,  and  the 
tincture  of  rhatany  is  an  astringent. 

Mouth-washes. — The  use  and  value  of  mouth- 
washes as  a  hygienic  measure  \\ill  now  be  con- 
sidered. For  patients  whose  ordmary  methods 
of  cleansmg  are  efficient  the  use  of  moutli- 
washes  is  superfluous,  but  they  become  very 
useful  adjuncts  to  those  who  experience  a 
difficulty  in  cleansing  then  teeth  and  gums, 
or  whose  efforts  are  not  equal  to  their  mten- 
tions,  and  who  suffer  from  much  caries  or 
gingivitis  in  consequence.  But  the  habitual 
use  of  mouth-washes,  purely  as  a  hygienic 
measure,  is  to  be  deprecated,  as  liable  to  do 
injury  in  time  to  the  mucous  membrane  of  the 
mouth ;  and  those  jjatients  whose  moutlis 
seem  to  be  especially  needing  the  use  of  a  mouth- 
wash are  just  those  who  should  be  urged  to  use 
more  efficient  means  of  natural  and  artificial 
mechanical  cleansmg.  In  jirescribing  a  mouth- 
wash for  a  patient's  habitual  use,  it  is  necessary 
that  its  object,  methods  of  use,  and  limitations, 
be  first  explained,  as  otherwise  it  may  result  m 
nothing  but  a  delusion  and  a  snare ;  for  the 
careless  and  uninitiated  may,  and  often  do, 
consider  the  antiseptic  properties  of  the  wash 
all  that  is  to  be  desired  to  counteract  the  fer- 
mentation and  putrefaction  in  the  moutli,  and 
do  not  realize  that  the  wash  will  not,  to  any 
appreciable  extent,  penetrate  the  mucous  plaques 
of  bacteria  and  deposits  of  food  about  the  teeth. 
It  is  essential,  therefore,  that  the  mouth  and 
teeth  should  be  cleansed,  as  described  above, 
a-id  the  debris  about  the  teeth  removed  or  at 
any  rate  loosened,  prior  to  the  use  of  all  moutli- 
washes,  which,  if  antiseptic,  will  then  inhibit 
the  growth  of  the  bacteria  lying  loose  or  in 
the  now  thinned  film  that  may  be  left  between 
the  teeth.     Thus,  if  the  bacterial  colonies  are 


removed  every  twelve  hours  and  mouth-washes 
used,  the  teeth  and  gums  should  remam  healthy ; 
for  a  mass  of  bacteria  such  as  would  be  dangerous 
as  uifection  or  as  an  acid-producer  can  hardly 
grow  from  a  thm  bacterial  film  m  less  than 
twenty-four  hours  (10).  It  is  impossible  to 
get  rid  of  all  the  bacteria  by  the  use  of  anti- 
septic mouth  -  w  ashes.  Rliller's  experiments 
proved  that  they  could  be  apparently  removed 
for  tlie  time  bemg,  but  that  after  a  few  hours 
they  were  as  plentiful  as  before ;  this  was  at 
any  rate  true  of  those  bacteria  habitual  to  the 
mouth ;  those  \\hose  natural  habitat  is  not  in 
the  mouth  can  be  eSectually  removed  by  anti- 
septic washes  and  mechanical  cleansing  (4, 
p.  158).  One  cannot,  therefore,  hope  to  sterilize 
the  oral  cavity,  but  its  condition  can  be  im- 
proved. The  difficulty  lies  in  the  choice  of 
drugs;  for  most  of  those  that  are  able  to  kill 
bacteria  or  uiliibit  their  growth  are  liable  to 
damage  the  mucous  membrane  of  the  mouth. 

There  are  two  distmct  kmds  of  mouth-washes  : 
firstly,  those  that  will  neutralize  the  acidity 
caused  by  fermentation  in  the  mouth ;  and 
secondly,  those  whose  antiseptic  properties 
wiU  kiU  or  inliibit  the  growth  of  bacteria.  The 
former  are  of  special  use  where  there  is  hyper- 
acidity from  fermentation  or  otherwise,  and 
where  caries  is  rampant,  especially  in  those 
cases  where  caries  is  proceedmg  extensively 
around  the  cervical  marguis  of  the  teeth.  The 
alkaline  salts  that  have  been  found  to  be  of 
most  service  are  the  magnesium  salts ;  all 
others  are  so  readily  soluble  that  they  are  very 
easily  washed  away,  if  used  alone.  Tlie  most 
convenient  and  effective  form  to  use  is  the 
hydroxide  or  hydrate  of  magnesia  (Mg  (H0)o), 
sometimes  called  "  milk  of  magnesia  "  when  ui 
solution.  This  is  prepared  by  the  mteraction 
of  magnesium  sulphate  and  solution  of  ammo- 
nia, and  collection  of  the  precipitate,  which  is 
washed  until  the  washing  ceases  to  give  a 
reaction  to  sulphates  (7,  p.  90).  The  following 
is  the  strength  that  should  be  used — 

R 


Magnesii  Hydroxidi 
Aquam  ad 

gr.  xxiv 

Sig.  M.d.  utend. 

A  teaspoonful  of  this  should  be  taken  into  the 
mouth  night  and  mornmg  after  cleansing  the 
teeth,  and  allowed  to  run  around  and  between 
all  the  teeth,  and  not  washed  away  by  further 
rinsing. 

Of  the  antiseptic  washes  only  weak  solutions 
can  be  used,  owing  to  tlie  risk  of  injury  to 
the  mouth.  Either  carbolic  acid  (1  in  200), 
formalin  (1  m  4000),  or  hydrogen  peroxide  (two 
volumes),  may  be  used  once  or  twice  a  day  after 
cleansing   the   teeth.     A   combmed   and   more 


333 


elegant  wash  may  be  made  up  as  follows  for 
the  same  purpose — 

R 

Liq.  Formaldehydi  (40  »;)     1   ._.   :.  g_. 
Tr.  Ivrameriae.    .         .        .     |  ' '    >>    ' " 
01.  Gautheriae    .        .        .     |  ..  - 
01.  Menth.  Pip.  .        .        .1  ''^  '^ 

Sp.  Rect 5  i^'- 

M.  Fiat  collutorium. 
Sig. — Add  a  few  drops  to  a  third  of  a  tumblerful 
of  water. 

Any  of  these  should  be  kept  moving  about  the 
mouth  for  at  least  a  minute,  and  it  is  important 
that  the  action  of  the  cheeks,  lips,  and  tongue, 
should  always  be  brought  vigorously  uito  use 
in  order  to  keep  the  wash  forcibly  passing  be- 
tween the  teeth.  Wadsworth  (23)  was  the 
first  to  advocate  that  a  30  per  cent,  solution  of 
alcohol  in  water,  to  which  is  added  glycerine, 
sodium  chloride,  and  sodium  bicarbonate,  was 
a  much  more  efficient  wash  than  the  ordinary 
antiseptics  for  removing  the  secretion  and 
infectious  deposits  from  the  mouth,  and  de- 
stroying the  bacteria,  the  salts  aiding  the 
dissolution  of  the  mucm,  epithelial  debris,  and 
coagula.  The  writer  suggests  the  following, 
which  he  has  found  most  useful,  being  more 
pleasant  to  use,  but  somewhat  weaker  than 
Wadsworth  recommended — 

R 

Sod.  Chlor.      . 

Sod.  Bicarb.    . 

Aq.  Cologn.     . 

Sp.  Pect. 

Aq.  ad     .        .        . 
M.  Fiat  collutorium. 
Sig. — "  Use  a  large  teaspoonful  with  an  equal 
quantity  of  water  to  swill  round  the 
mouth  and  between  the  teeth  for  at 
least  a  minute." 

During  illness,  especially  all  febrile  conditions 
and  pregnancy,  the  saliva  is  more  mucoid  and 
stickj%  and  therefore  acid  fermentation  Ls  much 
more  likely  to  take  place  in  situ  upon  the  teeth, 
esjiecially  as  the  diet  is  probably  of  the  soft 
carbo-hydrate  variety,  or  milk  alone.  The 
absence  of  true  mastication  will  cause  stagnation 
in  the  mouth,  and  the  teeth  may  be  rapidly 
destroyed.  It  is  essential,  therefore,  that  special 
attention  be  paid  to  the  teeth  at  such  times. 
The  tooth-brush  should  be  freely  used  after 
each  meal  if  possible,  and  the  mouth  ^\ell  rinsed 
with  some  antiseptic  wash.  If  the  patient  is 
too  ill  to  do  this  himself,  the  nurse  should 
cleanse  the  mouth,  either  with  a  brush  or  lint 
dipped  iti  some  aTitiseptic. 

Periodical  Cleansing. — Apart  from  the  daily 
treatment  adopted  by  the  patient,  it  is  advisal)le 
that  the  teeth  and  mouth  should  be  clean.sed 


-  aa  gr.  xxx. 
3  vnj. 


periodically  by  the  dentist.  The  frequency 
will  vary  according  to  the  adequacy  and  thor- 
oughness of  the  patient's  own  daily  cleansing, 
and  the  tendency  to  caries  and  the  accumu- 
lation of  tartar.  But  the  more  frequent  the 
treatment,  the  less  will  be  the  liability  to  caries 
or  oral  sepsis.  G.  H.  Wright  of  Cincinnati 
and  D.  Smith  of  Philadelphia  advocate  fort- 
nightly, or  at  least  monthly,  visits  by  their 
patients  for  extreme  cleansing  and  massage, 
and  they  describe  their  treatment  as  "an 
enforced,  radical,  and  frequent  change  of  environ- 
ment for  the  teeth  and  perfect  sanitation  for 
all  oral  conditions  ".  They  claim  that  by  this 
continual  polishmg  of  all  the  aspects  of  the  teeth 
they  have  reduced  the  tendency  to  caries  in 
their  patients  to  a  very  great  degree.  In 
practising  such  prophylactic  measures  as  these, 
or  even  to  a  less  degree,  the  theory  of  it  must 
first  be  j^ropounded  to  the  patients,  and  their 
interest  aroused  comjiletely  to  its  importance 
and  utility ;  otherwise  the  treatment  will  meet 
with  little  or  no  success,  for  they  will  be  apt 
to  rely  too  much  upon  the  periodical  scour,  and 
too  little  upon  their  own  cleansing.  The  result 
is  due  as  much  to  the  patient's  zeal  and  thorough- 
ness in  carrying  out  daily  the  instructions  given, 
as  to  the  dentist's  professional  skill  and  handi- 
work. 

For  projjhylactic  treatment  to  be  suc- 
cessful all  conservative  work  in  the  mouth 
must  be  as  perfect  as  possible,  so  as  to  allow 
no  chance  for  lodgements ;  all  septic  roots  must 
be  extracted,  and  abscesses  and  pyorrhoea 
alveolaris  cured.  At  the  periodical  visit, 
whether  it  be  fortnightly,  monthly,  or  at  greater 
intervals,  the  teeth  should  first  be  completely 
freed  from  all  calcareous  deposits  above  and 
below  the  gum  margins  with  suitable  scalers, 
and  attention  then  paid  to  all  the  aspects  of  the 
teeth,  special  care  being  given  to  the  approxi- 
mal  surfaces.  The  method  of  affecting  this 
cleansing  varies  ■^^•ith  different  practitioners, 
but  the  essential  matter  is  that  all  surfaces  must 
be  completely  freed  from  plaques,  whicli  gener- 
ally consist  of  decomposing  food,  mucus,  epithe- 
lial debris,  and  bacteria,  and  must  then  be  left 
in  a  polished  condition.  Tlie  simplest  method 
is  by  the  use  of  engine  brushes,  aided  by  finely 
ground  "  flower  of  pumice,"  moistened  with  a 
little  Eau  de  Cologne,  which  is  both  antiseptic 
and  fragrant.  The  bruslies  the  \vi-iter  has 
found  most  useful  are  those  whose  bristles  are 
set  end  on,  and  therefore  spread  out  on  being 
applied  to  the  teeth;  and  those  whose  bristles 
are  arranged  like  the  base  of  a  small  cone ;  both 
of  these  penetrate  bet^^•een  the  teeth  better  than 
most  others.  The  approximal  surfaces  are  then 
further  polished  with  waxed  floss  silk  as  described 
above,  and  finally  freely  sjTinged  with  hydrogen 
peroxide  (ten  volumes)  or  other  suitable  anti- 


334 


septic  solution  to  remove  all  traces  of  powder 
and  debris.  For  tliose  who  possess  a  com- 
pressed air  plant,  tlie  antiseptic  sjjray  Ls  a  very 
useful  adjunct  to  this  periodical  cleansing.  It 
is  applied  to  all  parts  of  the  teeth  and  gums,  any 
mOd  antiseptic  solution  being  used,  at  a  pressure 
of  about  thii'ty  or  forty  pounds,  and  is  employed 
to  advantage  before  and  after  the  scaling,  and 
again  after  the  polishing.  It  is  advised  (12) 
that  before  the  polishing  the  spray  should  con- 
sist of  warm  ^\•ater  with  a  little  aromatic  spirit 
of  ammonia,  in  order  to  dissolve  the  mucous 
coating  of  the  plaques  of  bacteria.  In  using 
the  spray,  especially  in  cases  of  marked  oral 
sepsis,  the  precaution  is  adopted  by  some 
operators  of  wearing  a  celluloid  or  fine  gauze 
mask  to  protect  themselves  from  infection  of 
eyes  or  air  passages  by  the  spray  passing  back 
from  the  patient's  mouth. 

There  is  a  prophylactic  method  of  oil  polishing 
(13)  which  is  claimed  by  its  author  to  give 
beneficial  results.  Fine  precipitated  chalk  is 
mixed  with  vaseline  oil  to  form  a  stiff  paste  and 
applied  by  rotary  brushes  after  drying  the 
teeth,  special  attention  again  being  given  to 
fissures  and  approximal  surfaces.  Quarterly 
applications  are  advised  for  children,  bakers, 
vegetarians  and  during  pregnancy,  and  half- 
yearly  applications  for  all  other  patients ;  and 
one  daily  application  also  is  recommended  for 
use  by  the  patients  themselves. 

Treatment 

Silver  Nitrate. — There  are  other  methods, 
which  are  occasionally  adopted  by  some,  for  the 
preventive  treatment  of  dental  caries  and  the 
treatment  of  small  cavities  other  than  by  filling. 
The  principal  of  these  is  by  the  use  of  silver 
nitrate.  MUler  (19)  conducted  some  experi- 
ments by  rubbing  a  saturated  solution  of  silver 
nitrate  upon  teeth,  allowing  it  to  dry,  and 
subjecting  the  teeth  to  artificial  caries,  and  then 
again  treating  with  silver  nitrate.  The  pro- 
tective action  was  found  to  be  greater  when 
there  was  already  some  slight  decalcification, 
and  in  many  teeth  so  treated  it  was  found  that 
established  caries  was  completely  arrested. 
Therefore,  this  treatment  seems  to  be  specially 
indicated  for  readily  accessible  and  superficial 
caries,  and  for  carious  deciduous  teeth  that 
cannot  readily  be  treated  otherwise.  Black 
(4,  p.  231)  advises  the  following  method  of  use  : 
Apply  the  rubber-dam  and  thoroughly  dry  the 
surface  with  hot  air ;  apply  a  saturated  solution 
of  silver  nitrate  with  the  pomt  of  an  orange- 
wood  stick ;  leave  in  direct  sunlight  for  ten 
minutes  or  in  daylight  for  one  hour  till  deep 
black.  If  not  black  the  silver  nitrate  has  not 
been  reduced  and  is  soon  dissolved  out ;  the 
black  precipitate  is  insoluble.  It  is  uncertain 
whether   the   protective   action   is   due  to   the 


coagulation  of  the  contents  of  the  tubules  or 
to  the  formation  of  an  insoluble  precipitate 
therein.  There  is  another  method  of  use 
advised  by  L.  C.  Bryan  (5),  of  Basle,  for  children, 
where  deep  fissures  or  rough  surfaces  invite 
caries.  He  uses  a  40  per  cent,  solution  of  silver 
nitrate  as  follows  :  Apply  rubber  if  possible ; 
heat  shreds  of  asbestos  wool  to  burn  off  organic 
matter ;  with  these  apply  the  silver  nitrate 
solution  to  the  teeth ;  \^'ork  to  the  bottom  of 
the  fissures  with  a  quill  pick ;  if  possible  let  it 
dry  on  the  teeth  ;  repeat  twice  a  year.  The 
writer  has  had  no  experience  of  this  method. 

Potassium  Sulplwcijanide. — A  treatment  for 
the  staying  and  prevention  of  dental  caries  has 
been  devised  by  Michaels  of  Paris  (17),  based 
upon  investigations  on  the  biochemical  states 
of  the  saliva.  He  found  that  the  chief  chemical 
variations  associated  with  caries  were  the 
relative  amounts  of  alkaline  sulphocyanides  and 
ammonia  in  saliva.  In  those  cases  where  caries 
was  rampant  the  ammonia  was  in  excess  of  the 
sulphocyanide ;  and  in  those  cases  where  caries 
was  absent,  the  sulphocyanide  was  in  excess  of 
the  ammonia.  He  also  found  that  potassium 
sulphocyanide  given  internally  was  excreted 
by  the  saliva,  and  went  on  being  excreted  for 
some  considerable  time  afterwards.  He  there- 
fore devised  the  treatment  of  giving  three  times 
a  day  to  patients  with  rampant  caries  tablets 
containing  half  a  grain  of  potassium  sulpho- 
cyanide ;  the  caries  in  these  cases  was  checked 
and  no  further  cavities  developed.  These  facts 
have  since  been  confirmed  by  many  in- 
vestigators.    (See  Chapter  XI.) 

Gliange  of  Mouth  "  Flora  ". — Another  form  of 
treatment  \\ith  a  similar  purpose,  ba.sed  on  the 
principle  that  one  set  of  micro-organisms  will 
crowd  out  another,  has  been  devised  by  Kenneth 
Goadby  (8),  who  essays  to  eject  the  acid- 
producing  bacteria  from  the  mouth  by  means 
of  others  of  a  less  virulent  type.  His  method 
is,  first,  to  determine  the  type  of  organism  that 
j  is  present  in  largest  numbers ;  then  to  carefully 
,  cleanse  the  mouth  of  all  bacteria  as  much  as 
possible,  especially  the  most  prevalent  form ; 
and  freely  to  "  sow  "  the  mouth  from  time  to 
time  \\ith  the  spores  of  a  specially  selected  and 
innocuous  form  of  organism.  In  this  way  he 
claims  to  have  had  excellent  results  in  the  stay- 
ing of  rampant  caries.  The  treatment,  though 
ingenious  and  highly  scientific,  does  not  seem 
likely  to  be  universally  or  even  commonly 
adopted,  on  account  of  the  technical  difficulties 
for  the  ordinary  practitioner. 

Excision. — The  excision  of  dental  caries  to 
prevent  further  ravages  is  somewhat  limited 
in  its  scope,  though  useful  when  adopted 
judiciously.  It  is  only  in  treating  quite  shallow 
cavities  by  this  method  that  any  degree  of 
success  can  be  hoped  for ;    the  depth  of  the 


335 


caries  in  the  dentine  should  not  be  greater  than 
the  tliickness  of  the  enamel  (22).  The  carious 
spot  should  be  excised  by  means  of  small  files, 
carborundum  stones,  emery  discs  and  strips, 
and  finally  ])olished  with  pumice  powder  and 
whiting  on  wood  points.  Only  those  situations 
that  can  be  easily  and  habitually  cleansed 
afterwards  should  be  attempted ;  otherwise, 
with  the  dentine  exposed  caries  may  readily 
recommence. 

It  will  be  well  to  recapitulate  briefly  the 
essentials  of  dental  hygiene.  Its  importance  for 
preventing  both  pyogenic  infection  and  dental 
caries  is  without  question.  The  natural,  and 
probably  the  mo.st  efficient,  mode  of  cleansuig, 
is  by  the  proper  mastication  of  a  rational  diet. 
The  artificial  methods  of  cleansing  by  brushes, 
.silk,  picks,  and  canes,  are  laborious  if  efficiently 
done,  but  generally  necessary  on  account  of 
irrational  diet  and  insufficient  mastication. 
Dentifrices  and  mouth-washes  are  useful  ad- 
juncts, though  not  a  necessity  for  many  people. 
Periodical  cleansing  by  the  dentbt  is  essential, 
but  must  not  be  relied  upon  by  the  patient  as 
the  most  important  factor.  Other  methods 
for  the  prevention  or  inhibition  of  dental  caries, 
such  as  by  silver  nitrate,  altered  states  of  the 
saliva  (by  drugs  or  bacteria),  and  excision,  have 
all  a  somewhat  limited  application,  though 
useful  in  their  places. 

The  technicalities  of  efficient  dental  hygiene 
are  sucli  that  at  the  best  it  is  the  few  who  can 
profit  by  it  to  its  fullest  extent.  It  has  been 
well  said  (28)  that  with  regard  to  the  masses 
of  the  people,  if  it  was  possible  to  get  rid  of 
dental  caries  by  altering  the  character  of  the 
people's  food,  then  there  was  some  hope ;  but 
if  it  was  necessary  to  rely  upon  elaborate 
methods  of  cleansing,  prevention  of  caries  was 
hopeless. 

E.  B.  D. 
BIBLIOGRAPHY 

(1)  Austen,  H.  Effects  of  Drugs  in  Causation  of 
Dental  Caries.  Brit.  Med.  Jour.,  Sept.  1910, 
p.  772. 


(3 


(9 

(10 

(11 

(12 

(13 
(14 
(15 

(16 

(1" 
(18 

(19 
(20 

(21 

(22 
(23 

(24 
(25 
(20 
(27 

(28 


Badcock,   .1.    H.     The   Need   for   Correction   of 

Malposition   of   the   Teeth.     Brit.    Med.   Jour., 

Sept.  1910,  p.  771. 
Bennett,     Norman    G.     Dental    Hygiene    and 

National    Physique.     Brit.    Dent.   Jour.,    1904, 

Vol.  XXV.  p.  888. 
Black,  G.  V.     Operative  Dentistry,  Vol.  I. 
Bryan,  L.  C.     Dental  Review,  1904,  p.  1. 
BuRCH.\RD.     Dental   Pathology.   1908  ed.,  p.  393. 
Gabell  and  Austen.     Dental  Materia  Medica. 
GOADBY,  Kenneth.     The  Buccal  Secretions  and 

Dental  Caries.     Brit.   Med.   Jour.,   Sept.    1910, 

p.  769. 
Godlee,  Sir  B.  J.    Surgical  Aspect  of  Oral  Hygiene 

and  Oral  Sepsis.     Brit.  Med.  Jour.,  Nov.   1904, 

p.  1367. 
Head,  J.     Dental   Prophylaxis.     Dental  Cosmos, 

1908,  Vol.  L.  p.  317. 
Hunter,     W.    Oral     Sepsis.     Brit.    Med.     Jour., 

1904,  p.  1358. 
Kelly.     Prophylaxis.     Dental  Cosmos,  1909,  Vol. 

LI.  p.   1283. 
Kleinsorgen.    Dental  Cosmos,  1908,  Vol.  L,  p.  881. 
Marshall,  J.  S.     Operative  Dentistry,  p.  176. 
McKenzie,     H.     Care     of     the     Mouth      during 

General     Disorders.     Brit.    Med.    Jour.,     Sept. 

1910,  p.  620. 
Meerhof,  C.  E.     Oral   Prophylaxis.     Dental  Re- 
view, 1908,  p.  198. 
Michaels.      Transactions    of    Third    I nternatioruil 

Dental  Congress,  1902. 
Miller,   VV.   D.     Experiments  and   Observations 

on  the  Wasting  of  Tooth  Tissue.    Dental  Cosmos, 
1907,  Vol.  XLIX.  pp.  1,  109,  225,  677. 
Miller,  W.  D.      Preventive  Treatment  of  Teeth. 

Dental  Cosmos,  1905,  Vol.  XLVII,  p.  913. 
Mummery,  J.   H.     Susceptibility  and  Immunity 

to  Dental  Caries.     Brit.  Med.  Jour.,  Sept.  1910, 

p.  773. 
Read,    T.    .1.     Chemical   Changes   in   the   Mouth 

during  the  Mastication  of  Bread.     Brit.    Dent. 

Jour.,  Aug.  1901,  Vol.  XXII,  p.  590. 
Tomes  and    Nowell.     Dental  Surgery,   5th  ed., 

p.  280. 

Journal     of     Infectious     Diseases, 


Dental  Cosmos,  1907,  Vol.  XLIX, 


Wadsworth. 
Oct.  1906. 

W.\dsworth. 
p.  415. 

Wallace,  J.  Sim.  Causes  and  Prevention  of 
Dental  Caries,  p.  73. 

W.ALLACE,  J.  Sim.  Prevention  of  Dental  Caries. 
Brit.  Dent.  Jour.,  1910,  Vol.  XXXI,  p.  241. 

Wallace,  J.  Sim.  Effect  of  Food  Stuffs  in  Pre- 
vention of  Dental  Caries.  Brit.  Med.  Jour., 
Sept.  1910.  p.  617. 

Wheatly.     Brit.  Med.  Jour.,  Sept.  1910,  p.  621. 


CHAPTER  XIX 

TREATMENT   OF   CAVITIES   IN  THE  TEETH  BY   FILLING 


I.— EXAMINATION    OF    THE    MOUTH    AND 
TEETH 

Too  much  importance  cannot  be  attached 
to  the  care,  skill,  and  judgement  required  in  the 
thorough  examination  of  the  mouth ;  it  must 
be  accurate,  compreheiLsive,  and  exhaustive, 
so  that  any  opinion  or  advice  founded  upon  it 
may  be  of  the  utmost  advantage  to  the  patients 
who  entrust  themselves  to  the  dental  practi- 
tioner. It  is  in  all  cases  advisable  that  the  ex- 
amination should  be  periodical,  the  intervening 
periods  vaiying  in  different  cases,  according  to 
the  age  of  the  patient  and  the  predisposition 
to  caries  and  other  pathological  conditions.  In 
children  and  through  early  life  it  is  usually 
necessary  every  three  months,  later  on  every 
six  months,  and  in  some  cases  an  annual  ex- 
amination may  suffice.  At  the  first  visit  com- 
prehensive views  of  the  patient  should  be  taken, 
and  general  note  should  be  made  of  any  special 
feature  in  walk,  manner  of  speech,  habits,  etc., 
as  well  as  any  special  condition  such  as  preg- 
nancy, or  any  general  pathological  state  such  as 
diabetes,  etc.  More  detailed  exammation  may 
take  place  then  or  at  a  subsequent  sitting. 

A  systematic  record  should  be  made  of  every 
case,  the  card  system  now  so  much  used  in 
almost  every  department  of  life  being  the  most 
convenient  form.  A  useful  card  is  8  in.  by  5  in., 
and  on  the  left-hand  side  may  be  a  diagram  of 
the  mouth,  the  rest  of  the  card  being  ruled  ^\itll 
famt  blue  Imes  on  which  details  of  treatment, 
etc..  may  be  entered.  A  note  should  be  taken 
of  the  conditions  mentioned  iDreviously,  and  in 
the  case  of  chOdren  especially  the  exact  age 
should  be  entered.  It  is  also  a  good  plan  to 
take  models  at  stated  intervals ;  these,  to- 
gether with  the  wTitten  record,  afford  very 
valuable  data  at  a  subsequent  time.  The 
general  condition  of  the  teeth  and  gums  should 
also  be  entered,  especially  conditions  such  as 
hypoplasia  of  the  enamel,  abnormalities  in 
size  or  shajie,  suppression  or  early  erujition,  etc. 

The  examination  of  the  mouth  should  always 
be  conducted  in  an  orderlj'  manner.  Some 
practitioners  recommend  that  it  should  com- 
mence at  the  third  left  mandibular  molar  and 
proceed  to  the  third  right  mandibular  molar, 
and  then  return  from  right  to  left  in  the  max- 
illa ;  others  prefer  to  commence  at  the  middle 


line  and  work  in  a  posterior  direction.  Very 
little  importance  need  be  attached  to  the  order 
providing  some  system  is  used,  so  that  nothing 
shall  be  overlooked  and  that  each  tooth  shall 
receive  individual  examination.  As  j)ointed 
out  by  Johnson,  each  tooth  has  five  surfaces, 
therefore  time  must  be  devoted  to  this  matter, 
or  important  conditions  may  very  easily  be 
overlooked.  Nothing  is  more  likely  to  bring 
discredit  upon  a  practitioner  than  the  occur- 
rence of  pain  that  might  have  been  prevented 
by  a  more  thorough  examination. 

The  appliances  required  are  a  mouth  mirror, 
one  or  more  exploring  instruments,  floss  silk, 
water  syringe,  and  in  some  cases  an  electric 
mouth-lamp.  The  mouth  should  be  free  from 
deposits  of  salivary  calculus,  etc.,  and  should 
be  in  a  generally  clean  condition.  If  it  is  not 
so,  before  a  systematic  exammation  can  be 
made  it  must  be  brought  into  that  condition  by 
suitable  scaling  and  cleansing.  The  recently 
introduced  method  of  using  compressed  air 
medication  is  a  very  good  preliminary,  and  will 
soon  be  looked  upon  as  a  sine  qua  non  in  dental 
practice.  Some  sort  of  aii-  compressor  must  be 
employed,  the  simplest  type  being  a  hand  pump 
attached  to  an  air  receiver  capable  of  with- 
standing an  internal  pressure  of  at  least  forty 
to  sixty  poinids  to  the  square  mch.  The  air, 
under  pressure  and  capable  of  being  controlled, 
is  conveyed  to  a  spray  bottle  by  a  strong 
mdia-rubber  tube.  The  bottle  sliould  contain 
some  suitable  non-irritant  antiseptic,  such  as 
hydrogen  peroxide  or  comf)ound  glycerin  of 
thymol,  and  should  be  warmed  to  about  blood- 
heat  electrically,  or  otherwise.  Variously  shaped 
nozzles  may  be  used,  and  the  drug,  in  a  fine  state 
of  division,  and  delivered  with  considerable 
force,  is  applied  to  the  surface  of  the  teeth  and 
gums,  and  very  successfully  removes  food 
debris,  etc.,  the  thorough  examination  of  the 
mouth  being  thus  very  greatly  facilitated.  Many 
other  uses  may  be  foinid  for  the  compressed  air 
atomizer,  such  as  in  the  treatment  of  pyorrhoja. 
An  automatic  compressor,  the  pump  being 
actuated  by  an  electric  motor,  has  also  been 
introduced.  This  is  the  most  convenient  form, 
as  the  pressure  can  be  easily  controlled  and 
kept  uniform. 

The  mouth  having  been  rendered  clean  in 
the  maimer  indicated,  the  examination  may  be 


33(i 


337 


commenced  at  the  predetermined  tooth,  a 
mirror  being  in  the  left  hand  and  held  in  siicli  a 
position  that  it  may  be  used  either  as  a  rcfl(?ctor 
of  light,  or  to  give  an  image  of  the  tooth,  by  an 
alteration  of  the  angle  at  ^diich  it  is  held.  An 
exceedingly  useful  form  of  mirror  is  one  having 
a  double  surface,  with  a  reflector  at  what  would 
be  the  back  of  a  mirror  made  in  the  usual  way. 
This  is  especially  valuable  in  the  examination 
and  treatment  of  buccal  cavities,  where  the 
mirror  can  also  be  used  as  a  retractor  of  the 
cheeks.  If  preferred,  t«'o  mirrors  may  be  used, 
each  with  one  of  the  reflectmg  surfaces  as 
indicated.  The  exploring  instruments  should 
be  very  sharply  pointed,  and  so  bent  near  the 
extremity  that  all  positions  may  be  reached 
with  ease  ;  it  is  not  well  to  have  the  handles  too 
thin,  as  it  is  important  that  the  sensations 
conveyed  through  the  instrument  should  be 
conducted  to  a  sufficiently  large  area  of  the 
fingers  to  enable  the  touch  sensations  to  be 
accurate.  Each  tooth  should  be  looked  upon 
as  occupying  an  isolated  position,  and  all  the 
five  surfaces  should  be  examined  by  the  probe, 
the  most  difficult  being  of  course  the  medial 
and  distal  ones  when  the  teeth  are  tightly 
placed,  especially  the  area  between  the  actual 
point  of  contact  with  the  adjacent  tooth  and 
the  cervical  margm.  The  fine  point  of  the 
probe  should  be  introduced  here  with  as  great 
thoroughness  as  possible,  but  even  with  the 
greatest  care  a  small  cavity  may  easily  be  over- 
looked. If  the  point  of  the  probe  can  be  made 
to  stick  in  any  fissure  or  other  pit,  and  so  reveal 
a  softening  through  the  enamel,  that  may  be 
taken  as  a  general  sign  that  a  carious  cavity  is 
forming,  and  that  treatment  should  be  under- 
taken. Frequently  the  fissures  in  molars  and 
premolars  may  be  deep  and  stained,  but  unless 
softening  is  found  treatment  by  filling  should 
be  deferred,  as  with  suitable  care  on  the  part 
of  the  patient  (his  attention  having  been  directed 
to  it  by  the  dentist)  the  fissures  may  never 
degenerate  into  carious  cavities. 

After  careful  examination  as  above,  unwaxed 
floss  silk  may  be  passed  between  the  teeth  and 
drawn  to  and  fro  ;  if  any  rough  place  be  detected 
it  probably  indicates  a  carious  cavity,  but  the 
absence  of  such  a  fraying  is  not  conclusive 
evidence  of  a  perfect  condition,  as  frequently 
in  very  early  caries  the  enamel  edges  are  not 
sufficiently  marked  to  catcli  the  silk.  In  case 
of  doubt  the  best  method  is  to  dry  the  teeth 
thoroughly  with  absolute  alcohol,  after  intro- 
ducing a  napkin,  wool  roll,  or  even  rubber-dam  ; 
then  by  the  aid  of  the  mirror  and  the  electric 
mouth-lamp  a  slight  difference  in  translucency 
may  be  detected  if  caries  is  commencing. 
Before  doing  this  it  may  be  helpful  to  put  in 
separating  material  for  a  day  or  two,  or  an 
immediate  separation  may  be  made  at  the  time 


if  thought  desirable.  Frequently  very  definite 
opacity  is  found  when  the  actual  opening  of 
the  cavity  is  not  reached  by  an  exploring 
instrument,  witliout  separation.  Particular 
care  should  be  given  to  examining  the  edges 
of  existing  fillings  (if  present),  more  particularly 
if  they  extend  below  the  gingival  margin ;  the 
same  remark  applies  to  crowns  and  bridges. 
Artificial  dentures,  if  worn,  should  of  course  be 
removed  before  the  examination,  and  note 
should  be  made  of  their  construction  and  design, 
especially  the  portions  coming  in  actual  contact 
with  the  natural  teeth. 

The  occlusion  should  also  be  examined. 
For  this  purpose  the  patient  should  be  asked  to 
close  the  teeth  in  a  natural  manner,  leaving 
the  muscles  of  the  lips  and  cheek  in  a  lax  state 
(care  must  be  taken  to  see  that  the  "  bite  "  is  a 
correct  one) ;  the  lips  and  cheeks  should  then 
be  lifted  up  and  retracted  by  the  mirror  and  the 
forefinger  of  the  left  hand.  While  this  is  being 
done,  the  condition  of  the  gums  and  gingival 
margins  may  be  noted,  and  any  sinuses  or 
cicatrices  of  old  abscesses  may  be  investigated ; 
the  condition  of  the  palate,  tongue,  fauces,  etc., 
should  also  receive  attention.  It  is  well  to 
pass  the  tip  of  the  first  finger  over  the  buccal 
surfaces  of  the  gums,  as  by  this  method  alveolar 
abscesses,  exostoses,  etc.,  may  sometimes  be 
detected.  Finally,  any  sign  of  discoloration,  or 
loss  of  translucency,  suggesting  the  death  of  a 
pulp,  should  be  looked  for.  If  an  examination 
is  conducted  in  this  mamier  the  first  time  the 
patient  is  interviewed,  and  careful  notes  are 
made  both  as  to  present  conditions  and  also 
weak  spots  that  may  require  attention  at  a 
future  visit,  the  best  interests  of  the  patient 
wiU  be  studied,  and  much  time  may  be  saved 
later  on  when  the  case  comes  for  further  con- 
sideration and  advice. 

II.— EXCLUSION   OF   SALIVA 

In  the  treatment  of  teeth  it  is  necessary  to 
isolate  them  from  the  fluid  that  normally 
bathes  all  their  exposed  surfaces.  It  is  neces- 
sary in  order  that  a  perfect  and  unrestricted 
view  of  the  cavity  or  surface  may  be  obtained ; 
the  presence  of  saliva  both  obscures  and  distorts. 
It  is  necessary  in  order  that  the  cavity  may 
be  storUized  and  dehydrated ;  it  is  found  in 
practice  that  live  dentine  is  generally  more 
sensitive  when  wet  (this  however  is  not  always 
the  case,  and  the  very  act  of  dehydration  may 
cause  considerable  pain).  It  is  necessary  to 
keep  the  tooth  in  a  dry  state  in  order  not  to 
interfere  with  the  chemical  action  of  cements 
during  setting ;  and  also  when  cohesive  gold  is 
used,  as  any  moisture  will  quite  prevent  the 
thorough  welding  that  should  take  place  between 
all  the  laminae  as  the  filling  is  built  up. 


338 


A  large  variety  of  methods  liave  been  intro- 
duced from  time  to  time  to  secure  the  desired 
result.  It  is  impossible  to  go  into  all  the  details, 
but  a  general  indication  will  be  given  of  the 
methods    vvhicli    have   been   found   of   greatest 


{    -'■■ 

■  / 

/ 

/ 

^ 

Fig.  414. — Method  of  folding  a  napkin  before  intro- 
duction into  the  mouth.  It  should  be  folded 
upon  itself  once  or  twice  more  than  shown  in  the 
bottom  figure,  so  as  to  form  a  long  pointed  cone. 

service.  Occupying  the  foremost  place  is,  of 
course,  "rubber-dam";  this  was  introduced 
many  years  ago  in  the  United  States  b^^  Barnum 
and  since  that  time  has  never  been  superseded. 
Its  use  is  essential  in  many  cases,  more  particu- 
larly in  cohesive  gold  filling  and  in  certain 
root-canal  treatments,  but  its  application  is 
always  attended  with  considerable  inconveni- 
ence and  discomfort  to  the  patient,  and  there- 
fore for  short  operations,  and  particularly  in 
young  children,  other  methods  are  frequently 
to  be  preferred. 

The  Napkin. — Except  in  the  case  of  those 
patients  who  have  an  abnormally  free  flow  of 
saliva,  the  napkin  may  be  found  of  the  greatest 
possible  service.  The  most  useful  size  is  seven 
or  eight  inches  square :    it  should  be  made  of 


"  bandage  muslin "  cut  into  suitable  pieces 
and  should  be  quite  free  from  "dressing."  It 
can  be  obtained  ready  prepared  from  the  depots. 
This  is  much  superior  to  the  washable  napkin 
made  of  damask,  either  from  a  sanitary  or 
economic  point  of  view.  Some  operators  have 
suggested  the  placing  of  a  piece  of  rubber-dam 
in  the  folds  of  the  napkin  ;  this  sometimes  gives 
good  results. 

In  applying  a  napkin  to  the  upper  jaw,  it 
should  first  be  folded  diagonally,  and  then  upon 
itself  to  form  a  long  pointed  cone  (see  Fig.  414) ; 
a  portion  about  three  inches  from  the  point  is 
then  taken  between  the  thumb  and  first  finger 
of  the  right  hand  and  introduced  into  the  sulcus 
while  the  cheek  is  held  away  from  the  teeth  by 
the  left  hand  of  the  operator  (see  Fig.  415).  It 
should  be  tucked  up  opposite  the  orifice  of 
Stenson's  duct ;  the  rest  of  the  point  should 
then  be  snugly  packed  into  tlie  sulcus  above  the 
anterior  teeth,  the  lip  being  lifted  out  to  enable 
that  to  be  done.  The  tliicker  portion  of  the 
napkin  is  then  spread  out  over  the  lower  incisors. 


V 

Fig.  415. — Shows  napkin  in  situ  for  upper  teeth. 

and  acts  as  an  "  apron  "  if  any  debris  is  dropped 
during  the  excavation  or  filling  of  the  tooth. 

In  applying  the  napkin  to  the  lower  posterior 
teeth  (see  Fig.  416)  somewhat  the  same  pro- 
cedure should  be  followed,  but  when  the  napkin 


339 


is  being  tucked  along  the  lingual  side  of  the 
teeth  the  patient  must  be  requested  to  lift  up  the 
tongue;  this  enables  it  to  be  introduced  quite 


Fig.  416. — Shows  napkin  in  situ  for  lower  posterior 
teeth.  The  pointed  end  of  the  folded  napkin 
should  be  introduced  into  the  sulcus  after  the 
other  portion  has  been  introduced  on  to  the 
floor  of  the  mouth. 

on  the  floor  of  the  mouth,  thus  more  readily 
blocking    the    flow    of    saliva    from    the    sub- 
maxillary   and    sub-lingual    glands,    and    also 
being    kept    in    place    by    the 
tongue.     A  few  folds  of  white 
blotting  paper,   say,   one  inch 
square    or    less,    placed    over 
Stenson's  duct  on  the  side  to 
be  operated  on,  will  frequently 
be  found  a   valuable   addition 
to  the  napkin  in  the  lower  jaw, 
as  the  parotid  gland  is  a  very 
active  one  and  readily  responds 
to  the   stimulus  of   pam,  and 
always  on  the  side  from  which 
the  stimulus  arises ;   that  is  to 
say,     the     increased     flow     is 
unilateral,  in  contradistinction 
from  the  bDateral  flow  produced 
by  mental  stimuli.     The  use  of 
a  clamp,  either  with  or  without 
the  addition  of   "wings"  or  other  devices,  is 
frequently  a  great  help  in  the  retention  of  the 
napkin  in  the  lower  jaw. 


Wool  Rolls,  a  large  variety  of  which  have  been 
introduced,  are  preferred  by  some  operators  to 
napkins ;  they  may  be  retained  in  place  by 
being  either  tucked  into  the  sulcus  between 
cheek  and  gum  or  used  in  connection  with 
clamps  and  springs  (see  Figs.  417,  418). 

Small  discs  of  unglossed  pipe-clay  have  also 
been  advocated  for  application  to  the  orifices  of 
the  salivary  ducts. 

Wliere  any  of  these  methods  are  used  it  must 
not  be  forgotten  that  the  moisture  around  a 
tooth  is  not  due  only  to  the  salivary  glands, 
but  that  the  mmute  mucous  glands  found  in 
the  flap  of   gum   that   surrounds  the    cervical 


Fig.  417. — Harvard  wool-roll  clamp.  (Robert  Richter's.) 
Made  in  four  sizes.  To  fasten  the  cotton  roll  to  the  clamp  the  wire 
is  bent  somewhat  outwards,  the  roll  pierced  lengthways,  and  the  pin, 
with  roll  attached,  pressed  back  under  the  hook.  Either  two  separate 
rolls  or  one  long  roll  (as  shown  in  the  figure),  may  be  used.  {Dental 
Manufacturing  Co.,  Ltd.) 

portion  of  the  teeth  are  also  active :  it  may 
therefore  be  necessary  to  place  small  pledgets 
of  wool  saturated  with  mastic  varnish  in  the 


340 


inter-spaces  of  adjoining  teeth,  or  if  the  cavity 
approaches  the  cervical  margin,  the  surface  of 
the  mucous  membrane  may  be  thoroughly  dried 
and  pahited  over  with  "  liquid  amber "  (a 
sort  of  varnLsh  used  by  jewellers).  A  14  % 
solution  of  trichloracetic  acid  has  also  been 
recommended  for  application  to  the  free  edge 
of  gum  to  prevent  "  weepmg  "  ;  this  gives  very 
satisfactory  results  where  for  any  reason 
rubber-dam  cannot  be  applied. 

The  Saliva  Ejector  when  first  introduced  met 
with  considerable  oj)position,  but  its  use  is  now 
almost  universal,  and  if  simple  aseptic  pre- 
cautions are  taken  no  objection  can  possibly  be 
found  to  its  adoption.  It  is  important  that  the 
orifices  of  the  tubes  should  be  so  placed  that  the 


Fio.  418. — Simmons'  wool-roll  clamp. 
For  application  of  wool  rolls  to  lower  teeth.  The 
upper  teeth  rest  upon  the  upright  of  the  clamp ; 
the  mouth  is  thereby  held  open,  and  the  clamp 
held  firmly  down  in  place.  The  clamp  does  not 
touch  the  lower  teeth — simply  presses  the  rolls 
firmly  against  the  gimis  below  the  teeth.  The 
rolls  are  slipped  upon  the  sharpened  points  before 
the  clamp  is  placed  in  the  mouth.  [Dental 
Manufacturing  Co.,  Lid.) 

soft  tissues  of  the  floor  of  the  mouth  are  not 
sucked  into  the  holes,  as  in  this  way  considerable 
pain  may  be  caused. 

Rubber-dam. — As  indicated  above,  the  most 
thoroughly  satisfactory  method  of  obtaming 
dryness  of  a  tooth  or  teeth  is  by  the  use  of 
rubber-dam.  It  is  necessary  that  only  rubber 
of  a  good  quality  be  used,  so  as  to  minimize  as 
far  as  possible  the  liability  to  split ;  for  the  same 
reason  it  must  be  fresh  and  kept  in  a  well-fitting 
tin  case  when  not  in  use.  If  in  good  condition  it 
should  be  capable  of  returning  to  the  flat  after 
being  stretched  over  the  forefinger  ;  if  it  "  bags  " 
its  quality  Ls  doubtful.  A  light-surfaced  rubber 
has  been  supjjlicd,  and  for  use  in  the  back  of  the 
mouth  has  some  advantages.  Again,  some 
operators  advocate  a  "  twill  "  surface,  but  each 
operator,  getting  accustomed  to  a  particular 
make,  finds  that  he  can  get  the  best  results  with. 
it.  Rubber-dam  is  usually  supplied  in  three 
weights,  viz.  so-called  thin,  medium,  and  thick; 
the  latter  is  rarely  if  ever  used,  the  medium  being 
the  most   popular,   but  the  thin,   if  carefuUy 


manipulated,  is  both  less  painful  and  more 
easUy  adapted,  especially  in  the  case  of  upjier  and 
anterior  teeth. 

Before  any  attempt  is  made  to  apply  the 
dam,  the  teeth  in  the  neighbourhood  should  be 
carefully  examined  and  a  scaler  passed  over 
them,  as  even  a  small  portion  of  calculus  under 
the  cervical  flap  of  the  gum  may  prevent  the 
proper  adjustment  of  rubber  and  ligature. 
VVliere  approximal  cavities  exist  in  the  teeth  to 
be  treated,  it  is  also  most  important  to  smooth 
over  any  sharp  cervical  edges,  as  otherwise 
the  rubber  wiU  be  torn  at  each  attempt.  Much 
trouble  is  saved  if  the  rough  excavation  of  the 
cavities  is  made  before  the  application  of  rubber ; 
edges  can  then  be  trimmed  approximately  and 
much  waste  of  time  avoided.  It  is  well  always  . 
to  test  the  teeth  by  passing  silk  vip  in  the 
approximal  spaces ;  if  this  runs  into  place 
readUy,  without  any  fraymg  or  catching,  the 
rubber  may  be  expected  to  do  the  same. 

For  the  upper  anterior  teeth  some  operators 
prefer  to  use  a  triangular-shaped  piece,  but  a 
square,  6  in.  by  6  in.,  is  most  universally  useful ; 
for  molars,  especially  in  the  lower  jaw,  a  piece 
even  larger  may  be  required,  measuring  6  in.  by 
7|in. 

Rules  have  been  laid  down  by  some  as  to  the 
number  of  teeth  on  either  side  of  the  one  to  be 
operated  upon  that  should  be  included  in  the 
rubber.  No  general  rule  will  suit  all  cases,  but 
it  must  be  borne  in  mmd  that  if  too  few  teeth 
are  included  easy  access  to  the  cavity  may  be 
prevented ;  and  if  too  many  are  allowed  for,  the 
possibility  of  leakage  is  somewhat  increased, 
and  the  pain  and  discomfort  of  an  unnecessary 
number  of  ligatures  are  also  incurred .  Generally 
speaking  it  is  necessary  to  include  a  minimum 
of  three  teeth,  that  is  to  say,  one  on  each  side 
of  the  tooth  to  be  treated ;  in  a  few  cases, 
however,  it  may  only  be  necessary  to  pass  it 
over  two  teeth ;  while  in  isolated  teeth,  or  for 
a  cavity  on  the  occlusal  surface  of  a  premolar 
or  molar,  only  the  one  may  be  necessary.  When 
applied  to  a  lower  molar  it  is  generally  advisable 
to  include  a  molar  posterior  to  the  one  to  be 
treated,  as  the  "  bag  "  forward  of  the  rubber 
is  apt  seriously  to  inconvenience  the  operator ; 
this  is  more  particularly  so  if  the  cavity  is  a  distal 
one.  It  is  also  desii-able,  where  applied  to  the 
upper  teeth,  to  finish  on  a  premolar  rather  than 
a  canine,  as  a  ligature  is  more  difficult  to  retain 
upon  the  latter  than  the  former. 

The  position  in  which  to  punch  the  holes  is 
not  without  importance.  For  the  upper  in- 
cisors they  should  be  from  one  inch  to  one  inch 
and  a  quarter  from  the  edge  of  the  rubber; 
the  holes  should  be  nearly  a  quarter  of  an  inch 
apart  (between  centres)  unless  the  size  or 
position  of  any  of  the  teeth  is  abnormal ;  the 
distance  apart   should   be  even  greater  if   the 


341 


teeth  are  spaced,  or  if  much  recession  of  gum 
has  taken  place.  The  important  point  to  bear 
in  mind  is  that  there  should  be  sufficient 
width  of  rubber  completely  to  cover  the  gum 
between  the  teeth,  and  also  to  turn  under  the 
free  edge  of  gum  to  form  a  watertight  joint 
(see  Fig.  420) ;  at  the  same  time,  any  snqjlus 
rubber  only  "  bags  "  and  prevents  free  access 
to  the  cerv^ical  portion  of  the  cavity,  and  is 
much  more  likely  to  be  caught  and  torn  by 
instruments  than  if  it  were  taut.  The  holes 
ought  also  to  be  punched  in  an  arch  correspond- 
ing to  the  arch  of  the  teeth.  A  frequent  error 
is  to  make  the  holes  too  small,  in  fact  the 
Ains\\-orth  punch  as  ordLnarUy  supplied  by  the 
depots  should  have  at  least  two  more  holes  of 

Fig.  4Ht. —  To  illustrate  position  in  which  holes  should 
generally  be  punched  in  rubber-dam. 


Upper  incisors 


Upper  premolars  and  molars 

Lower  premolars  and  molars  the  same,  but  3  inches 
from  edge  of  rubber,  instead  of  \\  inch  as  above. 

Lower  incisors  in  arc  of  a  circle  2  to  3  inches  from 
the  edge  of  the  rubber. 

increasing  size,  so  that  the  rubber  when  stretched 
over  an  Ivory's  molar  (or  other  large)  clamj)  is 
not  so  liable  to  split  (see  Fig.  421).  Just  as  satis- 
factory a  watertight  joint  may  be  made  as  with 
the  smaller  holes,  without  the  increased  liability 
to  this  annoying  accident.  An  easy  method 
of  determining  the  position  of  the  holes  is 
slightly  to  stretch  the  dam  over  the  teeth  to  be 
included,  and  then  to  mark  the  centre  of  the 
cutting  edge  of  each  by  touching  lightly  with  a 
tine-pointed  probe.  The  same  method  may  be 
used  if  there  are  any  spaces  between  the  teeth 
due  to  the  loss  of  some  members  of  the  series. 

Upper  or  Lower  Anterior  Teeth. — The  rubber 
should  be  slightly  stretched  and  gently  passed 
over  each  of  the  teeth  in  turn — sometimes  a  slight 
smear  of  vaseline  on  the  under  surface  of  the 
rubber  will  considerably  facilitate  this  stage.    In 


case  of  nausea  in  the  application  of  rubber-dam, 
Louis  Jack  recommends  a  few  drachms  of  aqua 
camphora  used  as  a  gargle  in  mouth  and  throat. 
The  retractors  should  then  be  applied,  but  with- 
out any  "pull"  on  the  rubber;  this  enables 
both  hands  to  be  kept  free  for  tlie  adjustment 


INCORRECT  METHOD 


CORRECT  METHOD 


Fig.  420. — To  illustrate  the  method  of  tucking  in 
edge  of  rubber-dam  under  free  edge  of  gum  to 
form  a  watertight  joint  or  "  valve  ". 

of  ligatures.  If  the  edge  of  the  rubber  does  not 
turn  under  the  free  edge  of  gum  readily,  a  few 
touches  with  a  blunt  flattened  burnisher  (so- 
called  battle-axe  pattern)  will  usually  suffice ; 
it  is  always  desirable  to  do  this  before  the 
ligature  is  applied  rather  than  to  trust  to  its 
carrying  the  rubber  before  it,  for  leakage  is  then 
liable  to  occur,  because  sometimes  the  ligature 
masks  the  position  of  the  "  valve  "  of  rubber. 

The  ligature  is  usually  formed  of  waxed  floss 
silk,  but  waxed  "  twist  "  sOk  is  equally  good 
and  sometimes  seems  to  retain  its  position 
more  readily.  Cobblers'  thread,  with  thek 
special  wax,  has  also  been  used  by  some.  The 
knot  should  be  a  surgeon's  one,  and  a  double 
twist  in  the  first  portion  of  it  will  prevent 
slipping  while  the  burnisher  is  again  used  to 
adjust  the  ligature  into  place ;  when  this  is 
satisfactory  the  knot  should  be  completed, 
and  the  ends  cut  off  quite  close,  so  as  to  be  out 
of  the  way  of  instruments  later.  For  very 
sensitive  patients  it  may  be  advisable  to  apply 


o 


Fio.  421. — Plate  of  Ainsworth's  punch  showing  correct 
range  of  holes  that  should  be  supplied. 

novooaine  or  other  local  anaesthetic  to  the  edge 
of  the  gum  before  adjusting  the  rubber-dam  and 
ligature.  It  is  not  always  necessary  to  ligature 
each  tooth  included  in  the  dam,  but  it  is  generally 
advisable  to  put  one  on  the  tooth  to  be  treated. 
Small  pledgels  of  cotton- wool  saturated  in 
varnish  and  placed  in  the  inter-spaces  of  the 


342 


other  teeth  will  frequently  take  the  place  of 
ligatures,  and  be  very  much  less  pamful  in 
application ;  this  method  is  especially  applicable 
wliere  much  recession  of  the  gum  has  taken 
place.  Soft  copper  or  iron  "  binding  wire  " 
may  be  used  with  advantage  in  some  cases, 
where  there  is  a  difficulty  experienced  in  the 
application  or  retention  of  silk,  or  where  tlie 
cavity  is  near  the  cervical  margin.  In  order 
that  "the  rubber  may  not  slip  over  the  ligature, 
knots  may  be  tied  on  the  silk  before  application ; 
these  knots  should  be  so  placed  as  to  come  on  the 
lingual  surface  of  the  tooth.  Small  glass  beads 
may  be  tied  in  instead  if  preferred.  After  all 
the  ligatures  have  been  adjusted  the  retractors 
may  be  tightened,  and  an  unrestricted  view  of 


Fig.  422. — Rubber-dam  holder.     {H.  P.  Fernald's.) 

Co.,  Ltd.) 

the  cavity  should  result.  A  napkin  should 
be  placed  under  the  rubber  where  it  passes 
over  the  lower  lip,  and  if  weiglits  are  employed 
they  will  keep  it  in  place  by  catching  it  in  the 
clips.  Many  operators  prefer  Fernald's  wire 
frame  holder  to  take  the  place  of  retractors 
and  weights  (see  Fig.  422). 

Uf-per  Posterior  Teeth. — To  apply  the  rubber- 
dam  to  these  teeth  is  a  little  more  difficult  than 
the  foregoing.  Ligatures  can  be  used  near  the 
front  of  the  mouth,  but  are  much  more  difficult 
to  adjust  further  back.  For  the  molars,  there- 
fore, and  also  frequently  for  the  premolars, 
"  clamps "  must  be  used.  A  very  large 
number  of  these  have  been  designed  and  intro- 
duced from  time  to  time,  and  much  difference 
of  opuiion  has  resulted  from  a  comparison  of 
their  supposed   merits.     It   is   most  important 


that  a  clamp  should  accurately  fit  the  neck  of 
the  tooth  to  which  it  is  to  be  applied.     It  should 
have  sufficient  "  spring  "  to  retain  its  position 
against  the  strain  of  the  rubber,  and  it  should 
hold  the  rubber  out  of  the  way  so  that  easy 
access  may  be  obtained  to  the  tooth.     A  selec- 
tion  of   different    shapes,    therefore,    must    be 
kept,  and  the  clamp  should  always  be  tried  on 
the  tooth  before  being  used.     Where  a  clamp  is 
to  be  applied  the  procedure  may  be  in  either  of 
two  ways  :    [a)  The  rubber  may  be  passed  over 
the  tooth  and  held  in  position  by  the  left  hand 
while  the  clamp,  previously  placed  on  the  forceps, 
is  passed  over  the  tooth,  care  being  taken  to 
see  that  the  edges  of  the  rubber  are  turned  under 
the  cervical    edge  of    gum ;    (6)  the  "  blades  " 
of  the  clamp  may  be  passed 
through   the   hole   in  the 
rubber  so  that  the  points 
of   the   forceps    may   just 
pass  through  the  holes  in 
the  clamp;   the  rubber  is 
gathered  together  and  held 
in    the    left    hand,    while 
the    blades   of   the   clamp 
are    adjusted    exactly    in 
place    on  the  tooth ;    the 
rubber  is  then  spread  out 
and  carefully  worked  over 
the  tooth  and  clamp  with 
a  burnisher  or  other  blunt 
instrument ;  in  this  way  a 
water-tight  joint  may  be 
more    readily    made    and 
there  is  less  likelihood  of 
the  clamp  "  pinching  "  the 
edge  of  the  rubber.  Ivory's 
clamps  were  introduced  to 
facilitate  the  application  of 
rubber,  and  are  made  with 
a  little  process  of  metal  on 
each    side,    so    that    the 
rubber  is  held  clear  of  the 
blades  until  the  clamp  is  in  correct  position; 
the  rubber  is  then  released  by  a  blunt  instru- 
ment and  sprmgs  into  its  correct  place.     It  is 
necessary  to  punch  rather  larger  holes  for  these 
clamps,    but   their   use   greatly   facilitates   the 
application  of  rubber  in  many  cases.     Where 
more  than  one  clamp  is  to  be  used  the  posterior 
one  should  be  introduced  first  and  the  rubber 
brought  over  the  anterior  teeth  afterwards. 

The  procedure  in  the  case  of  lower  molars  or 
premolars  is  the  same  as  described  above,  except 
that  it  is  almost  always  necessary  to  pass  the 
clamp  through  the  rubber  unless  an  Ivory's 
pattern  is  used. 

Cervical  cavnties,  especially  those  in  the 
posterior  teeth,  frequently  present  great  diffi- 
culties in  the  application  of  rubber-dam ;  some- 
times it  is  quite  impossible  to  apply  it  without 


(Dental  Manufacturing 


343 


great  pain  and  inconvenience  to  the  patient, 
besides  considerable  damage  to  the  periodontal 
?nembrane.  In  these  cases  some  other  treat- 
ment has  to  be  adopted,  and  possibly  a  filling 
chosen  that  does  not  demand  absolute  dryness 
for  its  insertion. 

For  the  anterior  teeth  various  cervical  clamps 
have  been  introduced,  and  by  their  use  some 
otherwise  difficult  cervical  cavities  may  be  kept 
quite  dry  durmg  the  building  of  the  filling  (see 
Fig.  423).  The  cavity  should  be  partly  ex- 
cavated, and  a  temporary  gutta-percha  filling 
inserted  and  left  rather  full  and  packed  against 
the  free  edge  of  gum.  In  a  day  or  two  when 
this  is  removed,  the  cervical  margin  of  the 
cavity  will  be  better  defined  by  the  lifting  back 


Fig.  423. — Ivory's  adjustable  cervical  clamp. 
This  clamp  is  tightened  to  the  tooth  by  a  slide. 
It  may  be  adjusted  to  slide  higher  up  the  tooth  without 

being   removed    by   loosening    the   set-screw    and 

pushing  the  arm  attached  to  the  labial  jaw  farther 

through  the  slide,  and  then  tightening  the  screw 

again. 
Pin-holes  are  made  in  the  arm  to  prevent  any  tendency 

to   slip   on    large   teeth.      (Dental    Manufacturing 

Co.,  Ltd.) 

of  the  soft  parts,  and  the  application  of  the 
rubber-dam  and  cervical  clamp  much  facilitated. 

Where  some  posterior  teeth  are  missing,  as  for 
instance  in  the  case  of  a  distal  cavity  in  an  upper 
canine  \\ith  both  the  premolars  on  the  .same  side 
absent,  much  time  may  often  be  saved  if,  instead 
of  punching  a  hole  for  the  first  molar,  the  rubber 
is  merely  stretched  over  the  molar  and  a  blunt- 
edged  clamp  placed  upon  that  tooth  outside 
the  rubber.  This  serves  to  hold  the  rubber  out 
of  the  way,  and  the  adjustment  of  it  over  the 
intervening  space  is  easily  made,  whereas  if  a 
hole  is  punched  some  difficulty  may  be  ex- 
perienced in  finding  the  exact  position  for  it ;  if 
it  is  made  too  near  the  canine  hole  the  rubber 
will  be  pulled  away  from  that  tooth,  and  if  too 
far  away  the  rubber  will  "  bag  "  and  interfere 
with  the  clear  view  of  the  cavity. 

Where  rubber  is  applied  to  the  lower  jaw  it  is 
usually  necessary  to  use  the  saliva  ejector,  as 


the  difficulty  of  swallowing  is  sometimes  con- 
siderable ;  this  may  also  be  necessary  in  the  case 
of  the  upper  teeth. 

III.— SEPARATION 

Before  a  tooth  can  be  successfully  filled,  it  is 
frequently  necessary  to  obtain  a  certain  amount 
of  separation ;  this  is  especially  the  case  where 
the  teeth  are  somewhat  tightly  placed  or 
crowded  together. 

The  ideal  tillmg  entirely  restores  the  tooth  to  its 
original  contour,  and  as,  generahy  speaking,  the 
teeth  have  tended  to  ajjproximate  to  each  other 
with  the  progress  of  caries  and  loss  of  tissue,  so 
it  is  necessary  to  separate  to  allow  for  the  correct 
building  up  to  replace  this  lost  tissue.  Wliere 
gold  is  used  for  the  restoration  of  contour 
sufficient  separation  must  be  obtained  to  allow 
for  the  correct  polishing  of  the  contact  points 
before  the  teeth  come  into  their  normal  position 
agam.  Good  separation  also  avoids  the  neces- 
sity of  cutting  away  unich  tooth  tissue  before 
the  introduction  of  the  filling  or  inlay. 

The  methods  may  be  divided  into  Gradual 
and  Immediate. 

Gradual 

In  the  gradual  method,  some  material  is 
introduced  between  the  teeth,  and  by  its  change 
of  shape  the  desired  result  is  brought  about. 
It  is  usually  the  less  painful  and  more  satis- 
factory plan  where  it  can  be  used,  but  care  must 
be  taken  not  to  produce  too  much  pressure  on 
the  process  of  gum  between  the  teeth  or  per- 
manent recession  of  the  gum  may  result.  Some 
writers  lay  great  stress  on  this  point,  which 
should  not  be  overlooked.  In  certain  cases, 
however,  where  the  interstitial  gum  tissue  has 
become  abnormally  thickened,  o\\ing  for  instance 
to  the  irritation  of  a  rough  cervical  edge,  it  may 
be  necessary  deliberately  to  produce  pressure 
upon  it,  in  oi-der  that  a  clear  view  of  the  margins 
of  the  cavity  may  be  afterwards  obtained. 

The  most  certain  and  rapid  material  to  use 
for  separation  is  undoubtedly  rubber,  either  in 
the  form  of  wedges  or  blocks  of  various  thick- 
nesses, or  rubber-dam  rolled  up  to  the  required 
size.  In  either  case  the  rubber  is  stretched  and 
passed  up  between  the  teeth,  a  space  being 
allowed  to  remain  between  it  and  the  gum ; 
the  ends  are  then  cut  off  quite  close  to  the  teeth. 
As  a  rule  one  to  two  days  is  the  utmost  time  that 
should  be  allowed  to  elapse  before  the  patient 
is  seen  again,  as  the  action  is  rapid,  and  much 
pain  and  inconvenience  may  result  if  the  rubber 
is  left  in  too  long.  Even  after  twenty -four  hours 
it  may  be  advisable  to  substitute  some  non- 
expansUe  material,  which  may  be  left  in  untfi 
the  periodontitis  has  passed  away.  An  opera- 
tion on  a  tooth  immediately  after  separation 


344 


by  rubber  is  sometimes  exceedingly  paiuful.  In 
order  to  jDrevent  the  rubber  slipping  out  after 
separation  has  commenced,  or  to  prevent 
pressure  on  the  gum,  it  is  often  a  good  plan  to 
open  ujj  and  partly  excavate  the  cavity,  and 
fix  tlie  iiibber  with  gutta-percha  packed  in 
nearly  cold  while  the  rubber  is  kept  on  the 
stretch.  Another  way  of  avoiding  undue 
pressure  on  the  gum  where  there  are  two  adjacent 
carious  cavities  is  to  place  a  small  metal  bridge 
across  the  floor  of  the  space  with  its  ends  resting 
in  both  cavities. 

Another  means  of  effecting  separation  is  by 
the  use  of  cotton-wool.  It  is  best  applied  in  the 
following  manner.  Firstly,  roughly  excavate 
the  cavity,  cutting  away  sharp  edges  of  enamel. 
Then  wipe  out  -v^dth  carbolized  resin,  next  pass 
a  piece  of  waxed  ligature  sUk  between  the  teeth, 
and  pack  in  cotton-wool  from  the  lingual 
surface ;  when  the  space  is  quite  full  tie  the 
silk  tightly  around  the  cotton-wool,  making  it 
into  a  "  bale  ",  so  that  the  expansion  wUl  be  in  a 
medio-distal  direction.  If  the  cavity  is  very 
deep  or  sensitive,  a  sedative  dressing  may  be 
applied,  and  temporary  gutta-percha  packed 
into  the  deeper  portion  before  the  wool  is  packed 
in.  It  is  necessary,  however,  to  leave  room  for 
a  certain  bulk  of  wool,  or  the  resulting  separation 
wUl  not  be  -sufficient. 

Tape  folded  upon  itseK  until  just  thick  enough 
to  pass  tightly  up  between  the  teeth  is  another 
material  that  may  be  used.  This  may  be  put 
in  by  the  jMtient  instead  of  rubber  after  the  latter 
has  been  in  a  few  hours,  if  much  pain  has 
resulted.  A  wooden  wedge  made  from  a  lucifer 
match  may  also  be  easily  put  in  by  the  patient 
if  tape  is  inconvenient. 

Wedges  of  orange-wood  lightly  tapped  into 
place  with  a  mallet,  or  pressed  into  position 
with  specially  designed  forceps,  are  also  used; 
they  tend,  however,  as  rubber  does,  to  press  on 
the  inter-proximal  gum  tissue,  and  care  must  be 
exercised  to  prevent  this. 

Gutta-percha  packed  between  the  teeth,  if 
left  in  position  for  a  sufficient  length  of  time, 
wUl  produce  separation,  but  this  is  brought 
about  more  by  the  pressure  of  occlusion  and 
mastication  upon  the  gutta-percha  than  by  any 
power  of  expansion  inliercnt  in  the  material. 


In 


Immediate 

immediate     separation    some    form    of 


mechanical  appliance  is  used  to  force  the  teeth 
apart.  Here  the  danger  is  that  the  enamel  may 
be  injured  at  the  point  of  contact  with  the 
instrument,  or  that  such  force  may  be  used  as  to 
cause  severe  periodontitis.  In  young  patients 
there  is  least  danger  of  either,  as  the  degree  of 
mobility  of  teeth  is  greater  than  in  those  of  more 
advanced  age,  but  in  all  cases  the  greatest  care 
should  be  exercised. 


Combination  of  Gradual  and  Immediate 

Probably  a  combination  of  both  methods  is 
the  most  desirable — the  use  of  a  separator  to 
obtain  the  preliminary  opening,  and  whOe 
it  is  still  in  situ  the  packing  in  of  gutta-percha 
with  cold  instruments ;  at  the  next  visit  of  the 
patient  all  inflammation  will  have  passed  away 
and  the  fillmg  may  be  completed. 

The  separators  as  supplied  are  either  in  the 
form  of  a  double  wedge,  gradually  approximated 
by  the  tightening  of  a  screw  (as  in  the  "  Uni- 
versal ",    etc.,   see   Fig.  424),   or   in  the   form 


Fio.  424. — The  "Universal"  separator.      (Dental 
Manufacturing  Co.,  Ltd.) 

of  "  cribs  "  applied  to  teeth  and  then  gradually 
separated  by  means  of  double -threaded  screws 
(as  in  the  "  Perry ",  see  Fig.  425).  In  the 
latter  type  the  j)ressure  is  spread  over  two 
points  on  each  tooth  instead  of  only  one,  and 
therefore  it  is  claimed  that  less  damage  is 
likely  to  result ;  by  means  of  rubber  or  impres- 
sion composition  placed  between  the  "  bow  "  of 
the  instrument  and  the  occlusal  surfaces  of  the 
teeth,  the  jaws  can  be  prevented  from  sliding  up 
and  injuring  the  soft  parts.     The  "  Perry  "  is 


Fig.  425. — The  "  Perry  "  separator.     (Dental 
Manufacturing  Co.,  Ltd.) 

especially  useful  for  the  posterior  teeth,  while 
the  so-called  "  Universal  "  is  sometimes  more 
readily  applied  in  the  anterior  region. 

IV.— GENERAL   PRIKCIPLES    OF   CAVITY 
PREPARATION 

It  frequently  happens  that  when  a  patient 
presents  himself  for  dental  treatment,  examina- 
tion of  the  mouth  will  reveal  a  number  of  teeth 
that  require  attention.  Before  a  reliable 
opinion  can  be  given  it  may  be  necessary  (and 
in  most  cases  it  is  necessary)  to  open  up  the 
cavities,  and  thus  determine  the  extent  of  the 


345 


disease,  and  form  a  mental  picture  of  the  most 
suitable  after-treatment.  If  the  moutli  is  not 
in  a  clean  state,  suitable  scaling  should  be 
undertaken,  the  teeth  should  be  polished,  and 
the  mouth  sprayed  with  the  compressed  air 
atomizer  previously  referred  to.  It  may  also 
be  advisable  to  give  the  patient  instructions  as 
to  the  use  of  the  tooth-brush,  etc.,  so  that  on 
the  next  visit  aU  the  teeth  may  be  found  in  a 
more  suitable  condition  for  treatment. 

All  the  cavities  should  then  be  opened  up,  and 
those  in  which  the  pulp  is  not  involved  may,  after 
slight  excavation,  be  dressed  vdth  oil  of  cloves 
or  other  suitable  obtundent,  and  sealed  with 
temporary  gutta-percha.  Attention  may  then 
be  directed  to  those  requiring  root-treatment. 
In  this  way  a  more  comprehensive  view  may  ' 
be  obtained  of  the  condition  of  the  dentition, 
and  while  treatment  is  being  undertaken  in  the 
teeth  ^^■ith  the  most  advanced  caries,  or  in 
those  that  have  been  giving  pain,  the  others, 
partly  excavated  and  sealed  up  wdth  antiseptic 
obtundent  dressings,  are  tending  to  become 
more  amenable  to  future  treatment.  During 
the  preliminary  opening  up  and  excavation 
the  carious  cavity  should  be  freely  syringed 
out  with  tepid  water  in  ANhich  some  pleasantly 
flavoured  antiseptic  has  been  dissolved.  It  is 
important  that  the  water  should  be  kept  near 
to  the  temperature  of  the  blood,  as  even  a  ' 
comparatively  slight  variation  from  this  may  ! 
cause  pain,  especially  if  there  be  an  exposed 
and  inflamed  pulp  in  the  tooth. 

A  chisel,  either  straight  or  curved,  is  the  most 
useful  instrument  for  the  preliminary  opening 
up   of   most   cavities.     It   must   be   kept   very 
sharp,  and  a  thumb-rest  must  be  found  before 
any  force  is  applied,  so  that  the  blade  shall  never 
reach  the  floor  of  the  cavity,  nor  the  cutting 
edge  slip  from  its  correct  position  in  case  of  , 
any  sudden   movement   of   the  patient.      The  j 
direction  and  "  cut  "  of  the  chisel  must  always 
be  so  arranged  that  the  line  of  cleavage  shall  j 
be  in  a   Ime  with,  and  so  between,  the  enamel 
prisms,    and    never    across    them.      The    chisel 
should  only   be   used   for   the    breaking   down 
of  enamel  that  is  unsupported  by  dentine.     A 
few    bold    cuts    \\ill    usually    suffice    to    give 
thorough  access  to  most  approximal  cavities, 
and  also  those   on   the  occlusal  surface  where 
fairly   extensive   caries   has   taken    place.      In  ! 
some  fissure  cavities,  howev^er,  it  is  necessary  ' 
first    to    use    a    cross-cut    fissure-burr.     These 
are  of  very  hard  steel,  and  consequently  care 
must  be  taken  when  using  lateral  pressure  to  I 
avoid    fracture.     The    point    should    be    intro- 
duced into  that  part  of  the  fissure  which  offers 
most  opportunity,  and  the  burr  should  be  di- 
rected along  the  line  of  tlie  fissure  ;  a  slight  saw- 
ing motion  facilitates  the  cutting.     The  cariou.s 
floor  of  the  cavity  should  be  avoided,  as   the  l 


cross-cut  burrs  are  liable  to  give  pain  when  used 
in  dentine.  It  will  be  found  that  enamel  is  most 
readily  cut  from  the  itiside  ;  the  burr  should, 
therefore,  be  so  directed  along  the  fissure  that 
it  tends  to  cut  the  enamel  from  within  outwards. 
The  cross-cut  burrs  require  frequent  renewal 
as  they  soon  become  dull ;  when  this  has  taken 
place  they  should  be  discarded.  Breaking  off 
the  terminal  y,,  inch  will  sometimes  allow 
another  unworn  portion  to  come  into  use 
and  give  a  fissure-burr  another  short  period 
of  usefulness.  Carborundum  wheels  and  points 
may  sometimes  be  used  in  the  preliminary 
treatment  of  enamel  walls,  more  especially  in 
molars  where  clearance  for  the  opposing  tootli 
has  to  be  made.  Enamel  walls  can  be  reduced 
in  height  very  readily  by  this  means. 

Wlien  free  access  has  been  made,  the  softened 
dentine  should  be  very  carefully  removed. 
Sharp,  straight  or  curved,  spoon  excavators  are 
generally  the  best  for  this  purpose.  They 
should  be  so  directed  that  the  carious  decalcified 
portion  is  flaked  up  around  the  edges  first,  and 
then  gradually  all  removed  towards  the  centre 
of  the  cavity,  special  care  being  taken  when  the 
instrument  has  to  approach  near  to  the  pulp. 
After  the  removal  of  all  softened  tissue  the  cavity 
has  to  be  shaped  to  receive  the  filling,  or  inlay, 
or  whatever  treatment  has  been  decided  upon. 
This  further  excavation  is  done  by  the  use  of 
round,  oval,  or  inverted-cone  burrs,  and  hatchet 
or  hoe  excavators.  Again  it  is  all-important 
that  every  mstrument  should  be  exceedingly 
sharp,  for  in  this  way  much  pain  and  time  may 
be  saved.  Dentine  when  cut  is  much  less  painjul 
than  tvhen  scraped;  therefore  all  instruments 
should  be  applied  at  such  an  aiu/le  that  real 
cutting  takes  place.  Too  much  stress  caimot 
be  laid  upon  this  point. 

The  shaping  of  a  cavity  demands  great  care 
and  consideration ;  the  outlines  of  the  subse- 
quent fUlLng  should  be  graceful  (this  is  specially 
important  for  gold  fillings  in  the  anterior  teeth), 
and  the  walls  should  be  sufficiently  strong,  not 
only  to  retain  the  filling,  but  to  bear  the  stress 
and  stram  of  mastication,  etc.  In  approximal 
cavities  endeavour  should  be  made  to  arrange 
the  junction  of  the  tooth  and  filling  in  such  a 
position  that  it  may  easily  be  kejit  clean.  The 
cervical  margins  of  cavities  demand  special 
attention;  the  position  of  the  junction  of  the 
enamel  and  cementum  must  be  clearly  defined, 
judgement  being  necessary  to  direct  the  excava- 
tion so  that  on  the  one  hand  weak  edges  of 
enamel  may  not  be  left,  and  on  the  other  that 
the  junction  of  filling  and  tooth  shall  not  be 
too  far  under  the  gum  margin.  In  approximal 
cavities  in  premolars  and  molars  the  buccal 
and  lingual  walls  should  be  kept  as  nearly 
parallel  as  possible.  Any  softened  patches  in 
the  enamel  in  the  vicinity  of  a  cavity  should  also 


346 


be  excavated  and  if  necessary  included  in  it ; 
likewise  some  developmental  pits  may  have  to 
be  cut  out  and  included  in  the  cavity  outline. 
Where  grooves  are  cut  in  the  dentine  for  reten- 
tion purposes  they  must  not  be  too  deep,  as 
there  is  great  danger  of  \\'eakening  the  wall  and 
of  leaving  inaccessible  portions  of  the  cavity, 
especially  when  cohesive  gold  is  to  be  used. 

The  final  treatment  of  the  enamel  edges  varies 
in  accordance  with  the  nature  of  the  filling 
material  to  be  used,  and  it  will  be  sufficient  in 
this  place  merely  to  lay  stress  upon  the  import- 
ance of  smooth  well-finished  edges,  so  that  there 
may  be  a  perfect  junction  between  the  tooth 
and  filling.  Very  sharp  chisels  are  again 
required,  and  now  the  edges  may  be  "  planed  ". 
Fine-cut  '"  finishing  "  burrs  are  also  very  useful, 
and  very  small  stones  mounted  on  thin  mandrels 
give  excellent  results.  Strips  and  discs  are  some- 
times necessary,  but  enamel  edges  bevelled  in 
this  way  are  apt  to  be  uneven,  as  it  is  difficult 
to  direct  the  cut  at  the  same  angle  with  the 
surface  in  the  different  parts  of  the  cavity. 

v.— SENSITIVE    DENTINE    AND    THE 
AVOIDANCE    OF    PAIN 

[For  Electro-therapeutical  Treatment,  see  Chap.  XXXI.] 

Much  has  been  written  on  this  subject,  and 
many  methods  have  been  introduced  to  over- 
come the  po«er  of  transmission  of  pain  through 
the  hard  portions  of  a  tooth  during  excavation 
or  other  necessary  treatment.  It  has  been 
stated  that  perfectly  normal  dentine  is  not 
sensitive ;  for  example,  in  fracture  of  a  portion 
of  the  cutting  edge  of  an  incisor  where  dentine 
is  exposed,  at  first  this  tissue  does  not  give 
rise  to  pain,  but  a  short  exposure  to  the  fluids 
of  the  mouth  makes  it  hypersensitive.  Again, 
all  the  teeth  in  the  same  mouth  may  show 
different  degrees  of  sensibility,  and  even  cavities 
in  different  jjortions  of  the  same  teeth  vary  in 
tlie  same  way.  The  dentine  near  the  cervical 
margin  is  invariably  more  capable  of  trans- 
mitting f)ain  than  the  rest,  especially  on  the 
buccal  surface  of  molars.  These  A\ell-known 
clinical  facts  can  be  explained,  to  a  certain 
extent  only,  by  the  structure  of  the  teeth ;  it 
can  be  readily  believed  that  dentine  in  the 
neighbourhood  of  the  "  granular  layer ",  and 
at  tlie  amelo-dentinal  junction,  would  be  more 
capable  of  transmitting  sensation  than  in  a 
somewhat  deeper  portion  of  the  tooth. 

Authorities  are  not  yet  agreed  as  to  the  exact 
nature  of  the  contents  of  the  dentinal  tubules ; 
the  outstanding  clinical  fact,  however,  is  that 
the  contents,  whether  nervous  tissue  (according 
to  the  recent  researches  of  Howard  Mummery) 
or  merely  protoplasmic,  are  capable  of  trans- 
mitting as  pain  to  the  sensorium  certain  stimuli, 
which  may  reach  them.     Another  fact  to  bear 


in  mind  is  that  not  infrequently,  especially  over 
the  cusps  of  the  j)osterior  teeth,  there  is  pene- 
tration of  the  enamel  by  the  so-called  "  enamel 
spindles  " ;  these  spaces  in  the  enamel,  being 
filled  with  the  same  tissue  as  the  dentinal 
tubules  and  connected  with  them,  are  capable 
of  giving  rise  to  considerable  pain  when  sub- 
jected to  cutting,  or  grinding  with  a  stone. 
There  is  jirobably  considerable  tactile  sense 
about  the  teeth,  quite  apart  from  the  sense  of 
pressure  that  may  be  recognized  through  the 
pericementum ;  for  instance,  the  crunch  of 
sugar  may  be  readily  differentiated  from  the 
crunch  of  a  cinder.  A  pulpless  tootli  has  much 
less  power  of  discrimination  in  this  way  than  a 
normal  one. 

Dentine  reacts  to  thermal  stimuli,  which 
however  are  interpreted  as  jMin,  not  as  a 
thermal  change.  It  also  reacts  to  bacterial 
products,  such  as  lactic  acid,  and  to  salt,  sweet, 
or  acid  substances  or  fluids,  as  well  as  to 
mechanical  stimuli.  The  exact  method  of 
transmission  has  not  yet  been  determined  ;  nor 
have  the  exact  histological  contents  of  the 
dentinal  tubules.  Burchard  gives  two  theories 
of  the  jihysical  phenomena  that  may  be  con- 
cerned in  the  process,  the  second  one  being 
favoured  by  him — 

(a)  That  a  contraction  of  the  whole  cell, 
fibril  and  odontoblast,  occurs,  sensory 
nerve-endings  being  pressed  upon  in 
the  act ; 

(6)  That  a  wave-like  motion  along  the  pro- 
toplasm is  set  up,  causing  excitation 
of  the  sensory  nerves,  and  due  to  the 
incompressibility  of  the  water  (Gysi). 

There  is  no  doubt  that  if  excessive  sensibility 
of  dentine  could  easily  be  avoided,  many  of  the 
difficulties  of  operative  dental  surgery  would 
vanish  ;  the  nervous  strain  on  both  patient  and 
operator  would  be  reduced  enormously.  Very 
many  methods  have  been  introduced,  and  all 
have  given  a  certain  amount  of  success,  but 
nothing  so  far  has  proved  thorouglily  and  uni- 
formly satisfactory.  The  ideal  method  should 
conform  to  the  following  conditions — ■ 

(1)  Ease  and  painlessness  of  application. 

(2)  Rapidity  of  action. 

(3)  Limitation  of  action  to  the  dentine,  with 

sufficient  penetration  to  allow  for  the 
painless  shaping  of  the  cavity. 

(4)  Non-irritation  of  the  pulp,   botli  at  the 

time  of  application  and  afterwards. 

(5)  Absence  of  discoloration. 

So  far  no  drug  or  method  has  been  introduced 
that  conforms  to  the  above  rather  exacting 
requirements ;  the  failures  have  been  so  many 
that  some  of  the  best  operators  have  come  to 
rely  principally  on  gaining  the  confidence  of 


347 


the  patient  and  on  firm,  decisive,  and  rapid 
cutting  with  perfectly  sharpened  instruments, 
by  wliich  they  claim  that  more  can  be  done  than 
by  the  use  of  any  special  drug,  etc.  The 
advantage  of  sharp  instruments  lies  largely  in 
the  fact  that  pressure  is  avoided,  as  this  causes 
more  pain  than  cutting.  Carious  dentine  is 
often  more  sensitive  if  cut  in  one  direction 
than  another.  Generally  speaking,  the  part 
just  under  the  enamel  is  the  most  sensitive, 
and  cutting  outwards  causes  less  pain  than 
driving  an  instrument  between  the  enamel  and 
dentine  and  then  cutting  inwards.  Neverthe- 
less, many  individuals,  especially  children, 
present  tliemselves  for  treatment  for  whom  it  is 
impossible  to  excavate  a  cavity  correctly  with- 
out the  use  of  some  method  for  reducing  the 
sensitiveness  of  dentine.  It  is  impossible  to 
mention  all  the  methods  that  have  been 
employed,  but  the  following  are  the  more 
important — 

Hot  Air,  especially  if  a  dehydrating  agent 
(e.  g.  alcohol)  is  used  in  conjunction  with  it ; 
the  application  at  first  may  be  very  painful,  and 
sometimes  the  pain  may  be  rather  prolonged. 

Cold  has  been  used  in  the  form  of  ethyl 
chloride  spray  directed  upon  the  sensitive  cavity, 
which  has  been  liglitly  filled  with  wool.  It 
is  frequently  very  painful  in  application,  and 
as  the  effects  are  somewhat  transient,  rapid 
excavation  has  to  be  done  before  recovery  of 
sensation;  there  is  also  danger  of  causing 
inflammation  of  the  pulp.  It  is  only  used  for 
shallow  cavities  in  tlie  anterior  teeth. 

Phenol  is  very  nuich  used,  especially  in  con- 
junction with  hot  air  ;  it  may  also  be  .sealed  into 
the  cavity  \\-ith  temporary  gutta-percha  with 
advantage. 

Oil  of  Cloves  is  used  in  the  same  way.  A 
combination  of  both  di'ugs  in  equal  parts  sealed 
into  the  cavity  for  some  days  seems  to  give 
better  results  than  either  used  separately. 

Zinc  Chloride. — F.  N.  Johnston  recommends 
the  following — 

R 

Zinci  Chloridi      .  .        .     gr.  xx. 

Alcohol         .        .  .        .     f.T  iv. 

ClJoroformum  ad  .        .     f  3  j. 

M.  (If  the  zinc  salt  does  not  make  a  clear 
solution  with  alcohol  add  a  drop  of 
hydrochloric  acid.) 

Silver  Nitrate  may  be  applied  either  in  the 
solid  form  or  in  a  50  %  solution.  If  in  the 
former,  the  most  con\'enient  method  is  to  melt 
a  small  bead  of  the  salt  upon  a  roughened  silver 
point,  care  being  taken  not  to  allow  it  to  become 
dish)dged.  This  is  important,  because  a  dis- 
lodged portion  might  easily  set  up  larjaigeal 
spasm  if  it  remained  in  tlie  air  passage,  or  if 


swallo^\■ed  might  set  up  ulceration  of  the 
stomach ;  a  prompt  dose  of  sodium  chloride 
would  of  course  counteract  the  latter.  The 
resulting  discoloration  of  the  dentine  when 
silver  nitrate  is  used  limits  the  use  of  this  drug 
very  considerably.  Fortunately,  however,  as  it 
is  extremely  efficient  in  many  cases,  the  dis- 
coloration is  usually  limited  to  the  decalcified 
dentine,  which  is  removed  on  a  subsequent 
occasion  in  the  preparation  of  the  cavity. 

Cocaine  has  been  advocated  and  may  be  used 
in  several  ^\ays ;  the  mere  application  of  a 
.solution  of  hydrochloride  of  cocame  to  the 
dentine,  even  if  sealed  in  for  some  time,  does 
not  appear  to  have  any  effect.  If,  however, 
pressure  is  used,  by  tlie  introduction  of  a  plug 
of  unvulcanized  rubber  pressed  into  place  with 
a  large-headed  plugger,  anaesthesia  of  the  dentine 
may  result ;  this  is,  however,  brought  about 
in  many  instances  by  the  cocaine  reaching  the 
pulp  tissue,  and  it  is  therefore  not  truly  an 
anaesthesia  of  the  dentine.  The  use  of  the 
so-called  "'  high  pressure  "  syringe  is  followed 
by  anaesthesia  of  the  pulp.  Its  use  is  only 
justifiable  when  the  removal  of  the  pulp  is 
intended;  it  should  not,  therefore,  be  employed 
in  ordinary  cases  of  hypersensitive  dentine,  if 
the  pulp  is  to  be  left  intact. 

Paraform  is  a  polymer  of  formaldehyde  and 
occurs  as  a  white  amorphous  po\\der  with  a 
pungent  odour.  It  is  exceedingly  powerful,  and 
must  be  used  with  the  utmo.st  caution  and  with  a 
definite  know  ledge  of  its  action.  It  is  especially 
useful  in  shallow  hypersensitiv^e  cavities  where 
a  dressing  can  be  left  in  contact  for  a  week  or 
more.  It  should  be  mixed  with  some  form  of 
temporary  filling  but  never  in  a  greater  propor- 
tion than  five  per  cent ;  care  must  be  taken 
that  the  paraform  is  evenly  distributed  through- 
out, so  as  to  avoid  the  possibility  of  a  concen- 
trated dose  upon  a  small  portion  of  dentine. 
The  most  convenient  preparation  is  that  made 
with  temporary  gutta-percha ;  it  should  not  be 
heated  more  than  neces.sary,  as  the  paraform 
tends  to  volatilize.  Another  preparation  may 
be  made  by  mixing  it  with  ox\^-sulphate  of  zinc  ; 
this,  when  mixed  into  a  paste  with  an  aqueous 
solution  of  gum  arable,  may  be  introduced  into 
the  sensitive  cavity  and  covered  with  temporary 
gutta-percha.  Paraform  should  not  be  used 
in  a  deep  cavity,  and  if  used  in  a  two  per  cent 
or  five  per  cent  proportion  should  be  left  in 
from  seven  to  fourteen  days ;  the  penetration 
is  sufficient  to  allow  of  excavation,  but  is 
localized  to  the  cavity  treated,  i.  e.  treatment 
of  a  cavity  on  the  occlusal  .surface  of  a  molar 
would  not  render  the  dentine  in  the  buccal  region 
insensitive. 

Trichloracetic  Acid,  10  to  15  %  solution,  some- 
times gives  good  results  if  the  dentine  be 
saturated  with  the  acid,  which   is  afterwards 


348 


evaporated  by  the  hot-air  syi'inge.     The  appli- 
cation may,  however,  be  rather  painful. 

General  Anodynes,  such  as  opium,  morphine, 
or  the  bromides  of  potassium,  sodium,  or 
ammonium,  have  been  used ;  in  ordinary  cases, 
however,  such  treatment  is  not  indicated.  In 
the  same  way  general  anaesthetics  have  been 
employed,  but  are  now  rarely  necessary. 

Local  Anaesthesia. — The  introduction  of  drugs 
like  novocaine,  and  the  improvement  in  sjTinges 
and  technique,  have  naturally  opened  up  a  field 
of  usefulness  in  application  to  conservative 
dentistry.  It  has  been  found  that  a  deep 
injection  m  many  cases  results  in  complete 
anaesthesia  of  several  teeth ;  this  of  course 
eiaables  perfect  excavation  to  be  made  without 
any  inconvenience  to  the  patient.  A.  H.  Parrott, 
of  Birmingham  (16)  (17),  by  means  of  a  special 
syringe,  makes  injections  into  the  bony  septum, 
by  means  of  which  he  claims  to  get  perfect 
anaesthesia  of  the  part  extending  to  the  pulp, 
and  thus  to  render  the  dentine  insensitive.  It 
may  be  by  such  methods,  rather  than  by  means 
of  drugs  applied  directly  to  the  dentine,  that 
success  may  be  achieved,  but  at  the  moment 
it  is  impossible  to  forecast  with  any  degree  of 
certainty. 

J.  A.  W. 

VI.— OBJECTS    AND    INTENTIONS    OF   TOOTH 
RESTORATION 

The  objects  and  intentions  in  filling  a  carious 
tooth  are  :  firstly,  to  arrest  the  progress  of  the 
caries  that  is  taking  place  in  the  tooth  ;  secondly, 
to  restore  the  usefulness  of  the  tooth  for  mastica- 
tion and  other  purposes ;  and  thii-dly,  to  prevent 
the  recurrence  of  the  caries,  that  is,  so  to  alter 
the  conditions,  that  having  been  once  arrested 
it  wUl  not  commence  afresh. 

In  considering  this  subject,  therefore,  it  is 
necessary  to  distinguish  between— 

(1)  Arrest  of  the  caries  (for  the  time  being) ; 

(2)  Prevention    of    its    recurrence    (at    some 

future  time) ; 

(3)  Restoration  of  function. 

1.  Arrest  of  Caries. — It  is  the  general  experi- 
ence of  dentists  that  caries  in  a  tooth  may  be 
inhibited  for  the  time  being  by  removmg  from 
the  tooth  all  the  tissues  affected,  and  replacing 
them  by  a  watertight  plug.  It  is  obvious,  liow- 
ever,  that  in  doing  this  the  pulp  must  not  be 
injured  or  exposed  to  mjury,  and  that  the  tooth 
must  be  left  strong  enough,  when  fiUed,  to  with- 
stand the  stresses  of  mastication,  as  failure  in 
either  of  these  particulars  would  render  useless 
the  success  gained  in  arresting  the  caries.  To 
remove  completely  all  that  part  of  the  tooth 
that  is  affected  by  caries  is  not  easy,  and,  as 
will  presently  be  seen,  is  not  always  desirable, 
nor  is  it  possible  in  all  cases  to  be  sure  that 


the  fillings  inserted  are  watertight ;  but  it  is 
admitted  that  the  more  nearly  perfect  the 
operation  of  filling  a  tooth  is  in  these  two  par- 
ticulars, the  more  certain  is  it  to  be  successful 
in  arresting  the  caries.  It  is  worth  while,  there- 
fore, to  consider  the  amount  of  latitude  that  may 
be  allowed — how  far,  in  fact,  the  fillings  may 
fail  in  being  watertight,  or  the  removal  of 
carious  tissues  fail  in  being  complete,  without 
endangering  success. 

The  affected  tissues  to  be  removed  may  be 
either  enamel  or  dentine,  and  to  ensure  their 
complete  removal  it  is  necessary  to  distinguisli 
them  from  those  parts  of  the  tootli  that  are  still 
sound.  The  first  effect  of  caries  on  enamel  is 
a  partial  decalcification,  probably  of  the  inter- 
prismatic  substance,  which  renders  the  enamel 
to  a  certain  extent  porous,  and  causes  this  dense 
and  translucent  substance  to  look  more  opaque  ; 
this  appearance  is  brought  about  by  the  per- 
meation of  the  enamel  by  a  substance  (saliva) 
with  a  lesser  coefficient  of  refraction  of  light 
than  has  enamel  itself  (just  as  air  mixed  with 
water  wiU  cause  the  opacity  of  foam),  and  one 
of  the  incidental  advantages  of  the  use  of  the 
rubber -dam  is  that  it  causes  the  carious  enamel 
to  be  more  easily  recognized,  since  dry,  porous 
enamel  is  even  more  opaque  than  w  et  (air  having 
a  lesser  coefficient  of  refraction  of  light  than 
saliva).  As  the  decalcification  proceeds  the 
enamel  is  gradually  disintegrated  and  broken  up 
into  minute  fragments ;  on  the  external  surface  of 
the  tooth  these  are  washed  away  by  the  saliva, 
but  should  the  decalcification  of  the  enamel  take 
place  from  the  side  of  the  dentine  (secondary 
enamel  caries),  the  fragments  can  be  seen  as  a 
I  white  cheesy  layer  between  the  enamel  and  the 
I  dentine.  Owing  to  its  opacity,  therefore,  carious 
1  enamel  in  any  position  can  be  easily  recognized, 
and  in  its  case  ocular  evidence  is  more  trust- 
worthy than  tactile,  since  partly  decalcified 
enamel,  even  though  opaque,  is  capable  of 
opposing  great  resistance  to  an  excavator  or 
a  burr,  and  even  to  a  chisel.  The  question 
how  enamel  affected  by  primary  caries  should 
be  dealt  with,  is  easily  answered :  it  should  be 
entirely  removed.  It  has  been  shown  that 
enamel  in  which  there  is  only  slight  loss  of 
translucency  may  be  quite  porous,  and  this 
bemg  so,  it  is  almost  certain  sooner  or  later  to 
become  disintegrated  and  break  dowai  alto- 
gether; there  can,  therefore,  be  no  justification 
for  leaving  any  such  opaque  enamel  at  the  edge 
of  a  filling  (26).  Nor  must  any  of  the  debris  of 
secondary  caries  of  enamel  be  left  in  the  cavity  ; 
in  addition  to  tlie  fact  that  such  debris  are 
loaded  with  micro-organisms,  their  presence 
shows  that  the  enamel  fibres  under  which  they 
are  seen — from  which  in  fact  they  have  been 
broken  off — are  unsupported,  i.  e.  are  not  con- 
tinuous with  sound  dentine.     It  is  known  that 


349 


such  fibres,  if  not  removed  (and  their  removal 
ia  generaUy  the  safer  course),  should  be  sup- 
ported by  an  adhesive  filling-material,  such  as 
oxy-phosphate  of  zmc,  this  being  the  treatment 
that  gives  them  the  best  chance  of  resistmg 
fracture  duruig  mastication ;  and  in  order  to 
make  such  a  filling  adliere,  all  trace  of  the 
cheesy  material  must  be  carefully  scraped  from 
the  under-surface  of  the  enamel.  The  rule, 
therefore,  Ls,  without  exception  :  all  enamel 
that  shows  any  signs  of  decalcification — any 
loss  of  translucency — should  be  removed. 

To  distinguish  sound  from  affected  dentine, 
reliance  is  placed  not  on  sight,  but  on  sense  of 
touch ;  it  is,  in  fact,  assumed,  that  hard  dentine 
is  sound,  while  dentine  in  any  degree  softened, 
i.  e.  decalcified,  is  unsound ;  and  for  present 
purposes,  it  is  probably  justifiable  to  make  this 
assumption,  though  Mller  (14)  has  shown  that 
the  tubules  of  even  hard  dentine  may  be 
invaded  by  bacteria.  The  best  means  of 
estimating  tlie  hardness  of  dentine  is  by  the 
use  of  a  sharp  spoon-excavator ;  with  this 
instrument,  better  than  any  other,  the  educated 
touch  can  tell  when  all  the  decalcified  dentine 
has  been  removed  and  tissues  of  normal  hardness 
have  been  reached. 

No  decalcified  dentine,  i.  e.  no  dentine  at  all 
soft  under  the  excavator,  should  be  left  under 
the  enamel  or  in  the  walls  of  the  cavity ;  this  is 
a  rule  that  admits  of  no  exception,  since  it  is 
plain  that  such  dentine,  even  should  the  process 
of  caries  become  arrested  in  it,  would  not  give 
sufficient  support  to  the  overlying  enamel  to 
enable  it  to  withstand  mastication,  and  would 
also,  owing  to  the  large  amount  of  moisture  in 
it,  greatly  increase  the  difficulty  of  inserting 
a  watertight  filling. 

As  regards  the  floor  of  tlie  cavity,  and  by 
floor  is  here  meant  the  pulp  wall,  the  course 
is  not  quite  so  clear.  It  has  until  lately  been 
the  accepted  teaching  (23,  pp.  286  and  402)  that 
a  certain  amount  of  soft  dentine  may  safely  be 
left  ui  this  position  as  a  protective  covermg  for 
the  pulp  agamst  thermal  irritation,  provided 
that  under  the  soft  dentine  a  layer  of  hard  den- 
tme  remams  to  protect  the  pulp  from  pressure  ; 
it  was  recommended  that  the  soft  dentme  left 
should  be  soaked  with  oil  of  cloves  or  some  other 
antiseptic,  and  by  some  authors  the  hope  was 
even  held  out  that  in  course  of  time  it  might 
become  recalcified  (10).  Lately,  however,  these 
views  have  undergone  considerable  cliange.  It 
is  pointed  out  that  softened  dentine  is  charged 
with  products  of  bacterial  growth,  which  act 
as  irritants  to  the  pulp ;  that  these  can  pene- 
trate to  the  pulp  even  through  a  layer  of  hard 
dentine  (20) ;  and  that  there  is  no  proof  that 
they  can  be  in  any  way  neutralized  by  antiseptic 
treatment.  It  is  also  stated  that  the  results 
of  this  treatment  in  the  past  have  not  been  good 


(11,  p.  141);  that  in  most  cases,  when  much 
soft  dentme  has  been  left,  the  pulp  has  either 
degenerated,  as  the  result  of  chronic  inflamma- 
tion, or  has  been  destroyed  by  acute  septic 
inflammation  (21).  The  practice  of  leaving 
softened  dentme  to  protect  the  pulp  seems  to 
have  been  fostered  by  the  belief  that  pulp 
trouble  following  on  a  filling  is  generally  due 
to  thermal  hritation ;  whereas  there  is  reason 
to  believe  that  in  most  cases  these  troubles  are 
of  septic  origin,  and  more  likely  to  be  caused 
than  prevented  by  leaving,  under  the  filling, 
material  charged  with  micro-organisms  and 
their  products.  It  is,  therefore,  now  generally 
taught,  that  it  is  better  to  remove  completely 
(11,  p.  141)  (3,  vol.  i,  p.  206)  (15)  (22,  vol.  u, 
p.  379)  aU  the  softened  dentme  from  the  floor 
of  the  cavity,  when  this  can  be  done  without 
exposmg  the  pulp,  and  to  insert  a  lining  of  non- 
couductmg  material  underneath  the  fillmg, 
should  thermal  irritation  be  feared.  When 
complete  removal  would  cause  an  expo.sure, 
there  is  perhaps  justification  for  leaving  over 
the  pulp  a  very  small  quantity  of  decalcified 
dentine,  more  especially  in  young  patients,  in 
whom  the  pulp  has  greater  vitality,  and  in  whom 
root-filling  involves  greater  risks ;  such  treat- 
ment, however,  should  be  restricted  to  those 
cases  in  which  there  is  no  history  of  the  spas- 
modic pam  characteristic  of  mflammation  of 
the  pulp,  and,  as  a  measure  of  precaution,  the 
dentine  left  should  be  rendered  sterile  as  far  as 
possible ;  it  is  generally  recognized,  however, 
that  if  any  large  quantity  of  softened  dentme 
is  left,  resulting  injury  to  the  pulp  is  almost 
certain  to  occur.  Should  no  trouble  arise 
from  the  pulp,  the  leaving  of  a  small  amount 
of  decalcified  dentine  on  the  floor  of  the  cavity 
does  not  seem  to  interfere  with  the  power  of  the 
fillmg  to  arrest  caries  (3,  vol.  i,  p.  206).  To 
sum  up,  then  :  in  order  to  arrest  the  progress 
of  the  caries,  all  carious  enamel  must  be  removed 
and  all  carious  dentine,  save  ui  some  cases  a 
minute  portion  covering  the  pulp,  and  even 
this  should  be  removed  if  it  can  be  done  without 
exposmg  the  pulp. 

The  second  question — Must  the  plug  be  water- 
tight m  order  to  arrest  caries  ? — is  a  more 
difficult  one  to  answer. 

It  can  hardly  be  doubted  that  many  fUIings 
that  have  rendered  excellent  service  in  the 
mouth  for  years,  are  not,  and  indeed  have 
never  been,  watertight.  But  it  is  pointed  out 
that  this  good  service  is  only  rendered  ia 
mouths  m  which  there  is  a  jjractical  immunity 
from  caries,  and  that  the  fiUhig  only  remauis 
serviceable  as  long  as  this  immunity  lasts  : 
should  the  immunity  disappear,  the  leak  serves 
as  a  starting  point  for  the  renewal  of  caries. 
The  fact  indeed  seems  to  be,  that  in  im- 
mune mouths  almost  any  filling  that  {prevents 


350 


effectively  the  lodgement  of  food,  is  sufficient  to 
arrest  the  caries  for  the  time  being.  It  must 
also  be  admitted  to  be  improbable  that  most 
iillmg-materials  are  an  effective  barrier  against 
micro-organisms  (25),  and  indeed  they  are  not 
used  by  the  ordinary  operator  in  such  a  way 
as  always  to  make  perfectly  watertight  joints 
(23,  p.  298) ;  but  in  spite  of  this  there  is  a 
consensus  of  opinion  among  dentists  that  the 
efficiency  of  a  filUng  in  causing  arrest  of  caries 
depends  largely  on  the  amoiuit  of  success 
attained  m  making  it  watertight  (22,  vol.  ii, 
p.  400)  (3,  vol.  i,  p.  192)  (11,  p.  153)  (23,  p.  383). 

With  the  present  limited  knowledge  of  the 
exact  conditions  under  which  caries  takes  place, 
it  is  impossible  to  be  too  dogmatic  ;  but  it  is 
probably  true  that  in  most  mouths  a  leaking 
filling  will  lead  sooner  or  later  to  a  renewal  of 
the  carious  process  in  the  cavity,  while  with  a 
watertight  filling  no  such  result  need  be  feared, 
and,  if  caries  recurs,  it  does  so  by  a  fresh 
decalcification  of  the  enamel  taking  place  at 
the  edge  of  the  filling. 

2.  Prevention  of  Recurrence. — Even  when  it 
has  been  arrested  for  the  time  being  by  a  suc- 
cessful operation,  caries  may  recur  later  at  the 
edge  of  the  filling.  This  may  happen  because 
an  uneven  joint  between  the  enamel  and  the 
filling-material  affords  lodgement  for  ferment- 
able material,  and  must  in  such  a  case  be 
attributed  to  faulty  technique  on  the  part  of 
the  operator,  or  to  defects  in  the  filling -material 
he  has  used ;  it  may  also,  however,  happen 
when  the  joint  is  perfect,  and  in  this  case  the 
recurrence  of  the  caries  must  be  due  to  the  non- 
removal  of  the  conditions  that  caused  it.  It 
is  to  remove  these  conditions  that  "  extension 
for  prevention  "  has  been  suggested,  and  it  is 
v\orth  « hile  to  consider  this  proceeding  in  some 
detail. 

The  principles  on  which  extension  for  preven- 
tion is  based  were  given  out  many  years  ago 
(18)  (24),  but  in  more  recent  times  they  have 
been  much  insisted  on  by  G.  V.  Black,  and  it  is 
from  his  writings  that  the  followmg  account  of 
them  is  mainly  taken.  It  is  pointed  out  by  him 
that  carious  cavities  may  be  divided  into  two 
groups,  according  to  their  origin — 

1.  Pit  and  fissure  cavities. 

2.  Smooth  surface  cavities. 

Pit  and  fissure  cavities  are  those  originating 
in  the  pits  and  fissures  to  be  found  m  the 
teeth;  these  occur  normally  on  occlusal  sur- 
faces of  molars  and  premolars,  on  Iniccal  surfaces 
of  molars,  and  sometimes  on  lingual  surfaces 
of  upper  incisors — m  irregularly  calcified  teeth 
they  may  be  found  in  any  part  of  the  enamel. 
Although  these  pits  and  fissures  do  not  generally 
extend  completely  through  the  enamel,  they 
act  as  starting-points  for  cavities,  since  they 


afford  lodgement  for  colonies  of  micro-organ- 
isms, which  grow  on  the  carbo-hydrates 
that  have  found  entrance  into  them,  and 
which  are  supported  by  the  fresh  supplies 
of  sugar  and  other  carbo-hydrates  coming  in 
from  the  mouth.  The  acid  generated  by  these 
micro-organisms  gradually  decalcifies  the 
enamel,  and  this  it  does  more  quickly  in  the 
direction  of  the  enamel  fibres  (that  is  towards 
the  dentine),  perhaps  because  the  cementing 
substance  between  the  rods  is  more  easily 
decalcified  than  the  rods  themselves.  When 
the  dentine  is  reached,  the  process  of  softening 
is  more  rapid  :  it  spreads  most  rapidly  in  the 
direction  of  the  tubules  and  under  the  enamel, 
the  result  being  an  area  of  softening  in  the 
dentine  of  pyramidal  shape,  with  its  base  to- 
wards the  opening  in  the  ennmel  (see  Fig.  426). 


Fig.    420. — C'arums  dentine   under  fissure   in   a  molar 
tooth  showing  pyramidal  shape  of  softened  area. 

In  these  cavities,  given  a  thorough  removal  of 
the  softened  dentine  and  the  frail  enamel,  and  a 
watertight  filling  with  perfect  edges,  there  is 
no  tendency  to  recurrence,  since  in  making  such 
a  filling,  the  pit  or  fissure,  the  predisposing 
cause  of  the  caries,  is  of  necessity  removed.  In 
them,  therefore,  no  extension  for  prevention  is 
required. 

Smooth  surface  cavities  are  cavities  not 
commencing  in  pits  or  fissures ;  they  occur  on 
the  buccal,  labial  and  approximal  surfaces  of 
all  the  teeth,  and  rarely  on  the  lingual  surfaces 
also.  The  caries  appears  first  as  an  opaque 
spot  on  the  smooth  translucent  surface  of  the 
enamel.  For  such  spots  to  occur,  it  is  believed 
to  be  necessary  that  micro-organisms  should 
have  become  attached  to  the  tooth  in  a  gela- 
tinous matrix  (zoogloea  formation),  which  pre- 
vents the  washing  away  of  the  acid  they  produce, 
and  so  leads  to  the  decalcification  of  the  enamel 


351 


on   which    they    are    fixed.     The    opaque    spot 
gradually  enlarges  and  finally  the  enamel  breaks 
down,  generally  at  the  point  where  the  opacity 
first  appeared,  and  the  cav-ity  in  the  dentine 
is  formed  in  the  usual  way.     If  a  section  of 
such  a  tooth  is  made,  it  will  be  found  that  the 
cavity  or  softening  in  the  dentine  is  of  the 
usual  pyramidal  shape — the  apex  towards  the 
pulp  and  the  base  towards  the  enamel ;   but  it 
will  also  be  found  that  the  enamel  is  more  ex- 
tensively carious  on  the  surface  than  in  its 
deeper  layers,  so  that  the  area  of  caries  in  it 
is  more  or  less  cone-shaped,  and  on  the  surface 
may  even  be  of  greater  extent  than  the  dentinal 
softening  (see  Figs.  427,  428).    In  this  particular, 
therefore,  these  cavities  differ  markedly  from  pit 
and  fissure  cavities,  in  which  the  decay  does  not 
spread  on  the  external  surface  of  the  enamel. 


any  quantity  of  enamel  may  ultimately  break 
down,  but  on  the  surface  the  caries  only 
spreads  to  a  certain  limited  extent.    There  are, 


KiG.  427. — Diagram  showing  largo  extent  of  carious 
enamel  iu  smooth-surface  cavities.  (G.  V.  Black  : 
Operative  Dentistry.) 

but  on  its  dentinal  surface,  where  it  is  secondary 
to  that  of  the  dentine. 

It  is  supposed  that  the  acid  generated  by  the 
micro-organisms  penetrates  the  enamel  more 
easilv  in  the  direction  of  the  fibres,  since  the 


Fig.  i2H. — i'hotograph  of  a  cross-soctiuii  of  a  pre- 
molar, showing  broad  whitened  areas  of  caries  of 
enamel  on  the  approximal  surfaces.  (G.  V.  Black  : 
Operative  Dentistry.) 

decalcification  is  greater  under  the  older 
zoogloea  formation  in  the  centre  of  the  opacjue 
spot  than  under  the  more  recent  i^eripheral 
portion.  Owing  to  the  softening  of  the  dentine 
and  to  consec|uent  secondary  caries  of  enamel, 


'  ^iiiiiiiiiiiiiiiiiiiuiijDjjjjg-  /  ViiiSiJSSiiSilSffllli^ 
Fig.   429. 


Fig.  430. 

A  diagrammatic  representation  of  caries  of  the  bucca 
surfaces,  Fig.  429,  and  of  cross-sections  of  the 
crowns.  Fig.  430,  of  tlie  lower  first  and  second 
premolars  and  first  and  second  molars,  showing 
the  location  of  caries  and  tendency  to  spread  in 
a  direction  aroimd  the  crowns  of  the  teeth, 
following  the  free  margin  of  tlie  gingivae.  In 
Fig.  429  the  dotted  line  represents  the  gingival 
line,  or  Ime  of  the  attachment  of  the  gum  tissue 
to  the  teeth.  The  continuous  dark  line  represents 
the  line  of  the  free  margin  of  the  gingivae,  which 
arches  toward  tlie  occlusal  surface  in  passing 
between  the  teeth.  The  double  Ime  represents 
a  saw-cut  dividing  the  crowns  through  the  areas 
of  carious  enamel.  Fig.  430  represents  the  areas 
of  carious  enamel  exposed  by  cutting  away  the 
crowns.  The  portions  darkened  represent  the 
parts  of  the  enamel  most  liable  to  caries,  while 
the  areas  left  white  at  the  medio-  and  disto-buccal 
angles  of  the  teeth  represent  areas  that  are  almost 
always  immune  to  caries.  (G.  V.  Black  :  Opera- 
tive Denti.strij.) 

in  fact,  certain  boundaries  that  it  does  not 
cross :  on  buccal  and  labial  surfaces  it  starts 
near  the  gum  margin  and  sjjreads  medio- 
distally  and  occlusally,  but  stops  short  of  the 
angles  of  the  tooth,  and  does  not  extend  oc- 
clusally beyond  the  ghigival  third  nor  reach 
underneath  the  gum  (see  Figs.  429,  430) ; 
on  approximal  surfaces  it  generally  starts  just 
underneath  the  contact  point  and  spreads  in 
every  direction,  but  stops  short  of  the  angles 
of  the  tooth,  and  does  not  encroach  on  the 
occlusal  surface  or  reach  beneath  the  gum  (see 
Figs.  431,  432). 

The  non-immune  area,  therefore,  or  area  over 
which  the  caries  may  spread,  may  be  seen  in 
both  these  cases  to  correspond  to  the  area  of 
the  tooth  over  which  food  is  not  driven  in 
mastication,  or  that  is  not  covered  by  gum.  It 
is  probable  that  the  gum-covering  and  the 
friction  of  food  both  prevent  the  zoogloea  forma- 
tion necessary  for  the  production  of  surface 
caries,  and  it  is  noticed  in  confirmation  of  this 
theory  that  the  non-immune  area  varies  under 
different  conditions  :  for  instance,  it  is  relatively 


352 


smaller  in  teeth  in  which  the  embrasures  or 
re-entrant  angles  are  large  (see  Fig.  433),  since 
the  approximal  surfaces  of  such  teeth  are  more 
exposed  to  the  friction  of  food;  and  it  is 
extended  gingivally  on  approximal  surfaces 
when  the  inter-proximal  gum  has  been  so 
flattened  by  the  impaction  of  food  as  to  be 
pushed  away  from  tlie  neck  of  the  tooth. 

In  preparing  a  smooth  surface  cavity  accord- 
ing to  the  ordinary  rules,  all  the  surface  enamel 


Figs.  431,  432. 

Diagrammatic  representation  of  the  areas  of  liability 
to  caries  on  the  approximal  surfaces  of  the  pre- 
molars and  molars.  Fig.  431,  and  on  the  buccal 
surfaces  of  the  premolars  and  molars,  Fig.  432. 
The  arching  of  the  free  border  of  the  gum  tissue 
as  it  passes  between  the  teeth  is  iUustrated  in 
Fig.  431.  The  form  of  this  arch  varies  greatly 
in  different  cases.  In  many,  and  particularly  in 
young  persons,  the  summit  of  the  arch  is  nearly 
flat  for  a  more  or  less  considerable  space.  (G.  V. 
Black  :  Operative  Dentistry.) 

that  shows  signs  of  decalcification  must  be 
removed ;  but,  at  least  in  shallow  cavities,  it  is 
not  an  uncommon  practice  to  polish  the  carious 
surface  with  tapes  or  discs,  so  as  to  diminish 
as  far  as  possible  the  area  over  which  such 
removal  need  be  made,  since  such  polishing 
completely  removes  the  opacity  at  its  most 
peripheral  part.     According  to  the  doctrines  of 


Fig.   433. — Caries   in   the  distal  surface   of  a  second 
premolar,  which  makes  a  broad  contact  with  the 
first  molar. 
a.  Large  en^brasures  or  re-entrant  angles. 
6.   Small  re-entrant  angles. 
The  second  premolar  and  first  molar  should  be  sepa- 
rated, the  premolar  cut  away  for  prevention,  and 
the  original  contour   restored  by  filling   material. 
(G.  V.  Black  :  Operative  Dentistry.) 

extension  for  prevention,  by  acting  in  this  way 
the  operator  is  courting  recurrence  of  caries, 
since  the  edges  of  the  filling  are  placed  in  a  non- 
immune area.  In  such  a  case  what  piobably 
happens  is  that  the  zoogloea  formation  starts 
again  in  much  the  same  place  as  before,  which 
will  be  somewhere  on  the  surface  of  the  filling ; 
as  before,  also,  it  gradually  spreads  peripherally, 
and  attains  or  even  exceeds  its  original  extent, 
so  that  unless  the  area  of  the  cavity  has  been 
made  at  least  coextensive  with  this,  there  is 


good  reason  to  expect  recurrence.  It  is  true 
that  filling  the  tooth  may  alter  the  conditions 
under  which  tlie  decalcification  went  on,  by 
enabling  the  patient  to  masticate  with  greater 
vigour,  or  that,  on  buccal  and  labial  surfaces, 
special  instructions  as  to  the  use  of  a  tooth- 
brush may  have  the  same  result ;  but  it  is  un- 
wise to  trust  very  much  to  the  effect  of  this 
alteration  of  conditions,  whicli  at  the  best  is 
but  problematical. 

To  carry  out  the  principle  of  extension  for 
prevention  in  its  entirety  it  is  necessary  to  go 
yet  further;  even  if  the  surface  decalcification 
has  not  extended  all  over  the  non-immune  area, 
all  that  area  should  be  cut  out  and  included  in 
the  cavity,  so  that  the  edges  may  be  placed  in 
positions  immune  from  caries.  Thus,  on  a 
buccal  surface  the  cavity  should  be  extended 
medially  and  distally  almost  as  far  as  the  angles 
of  the  tooth ;  occlusally  it  should  extend  at 
least  one-third  of  the  distance  from  the  gum  to 
the  occlusal  edge  ;  and  gingivally  it  should  reach 
as  far  as  just  under  the  free  margin  of  the  gum. 
Similarly,  ajiproximal  cavities  should  be  ex- 
tended below  the  gum,  above  the  contact  point, 
and  out  to  the  angles  of  the  tooth ;  this  will  have 
the  effect  of  placing  all  the  cavity  edges  clear 
of  the  non-immune  area,  on  the  so-called  self- 
cleansing  surfaces,  which  are  protected  by 
friction  from  the  feltmg  of  micro-organisms. 
It  is  believed  by  the  upholders  of  this  doctrine, 
that  in  susceptible  mouths  such  extended 
fillings  are  the  only  ones  that  are  effective  ;  and 
they  hold  that  in  these  mouths  the  extension 
should  be  made  even  at  the  expense  of  sound 
tissue.  It  is  true  that  in  all  mouths  a  layer  of 
micro-organisms  wiU  be  found  felted  to  the 
crowns  of  the  teeth  in  those  parts  less  exposed 
to  friction;  but  it  is  only  in  non-immune  or 
susceptible  mouths  that  tliese  plaques  seem  to 
have  the  power  of  causing  decalcification  of  the 
enamel  to  which  they  are  fixed.  This  would 
also  account  for  the  facts  already  mentioned, 
namely,  that  enamel  fissures  and  the  edge  of 
fillings  not  strictly  watertight  do  not  always 
act  as  startmg-points  for  caries.  On  the  whole, 
the  advocates  of  extension  for  prevention  would 
seem  to  have  established  their  position,  and  it 
is  now  generally  recognized  that  fUlings  inserted 
according  to  their  principles  are  most  to  be 
relied  on  in  preventing  recurrence  of  caries  at 
the  cavity  margin.  In  spite  of  this,  however, 
it  must  be  admitted  that  in  practice  the  com- 
plete carrjdng  out  of  the  23rocedure  is  not  always 
possible  or  perhaps  to  be  recommended.  In 
young  patients  and  in  those  with  sensitive  teeth 
— often  in  fact  in  those  very  cases  where  it  is 
most  desirable — the  difficulty  of  extending  a 
cavity  is  so  great  that  the  operator  must  be 
content  with  cutting  out  the  carious  tissues  and 
inserting  a  filling  as  best  he  can.     A  period  of 


353 


immunity  may  be  approaching,  in  which  case  ' 
the  filling  will  stand,  or,  should  the  worst 
happen  and  recurrence  take  place,  the  filling 
can  then  be  extended ;  the  first  filling  will  not 
have  been  useless,  since  by  arresting  the  caries 
in  the  deeper  parts  it  wiU  have  prevented  the 
involvement  of  the  pulp. 

3.  Restoration  of  Function. — In  order  to  re- 
store the  function  of  the  tooth,  the  tissues  lost 
by  caries  must  be  replaced,  and  the  crown  of 
the  tootli  be  built  up  to  its  original  shape. 

On  buccal  and  labial  surfaces  this  is  so 
obviously  necessary  that  no  comment  on  them 
is  needed.  On  occlusal  surfaces  the  exact 
reproduction  of  the  original  shape  of  the  tooth 
is  somewhat  subordinated  to  considerations  of 
strength,  in  so  far  that  the  cusps  need  not  always 
be  reproduced  in  their  entirety ;  but  any  great 
alteration  in  the  shape  of  the  surface  should  be  ; 
avoided,  as  the  effectiveness  of  the  tooth  for 
mastication  is  thereby  impaired.  On  approxi-  i 
mal  surfaces  the  restoration  of  the  original  shape 
is  a  matter  of  the  greatest  importance,  and 
indeed  much  of  the  success  of  the  operation 
depends  on  the  contouring  of  the  filling ;  it 
has  already  been  shown  how  insufficient  ! 
building  out  of  the  approximal  surface  may 
increase  the  area  predisposed  to  caries,  and  so 
be  a  cause  of  recurrent  caries,  and  it  will  be 
found  that  this  is  not  the  only  ill  result  that  is 
to  be  feared. 

In  a  healthy  mouth  the  triangular,  or  rather 
pyramidal,  spaces,  whose  apices  are  the  contact 
points  and  whose  bases  are  the  portions  of  the 
alveolus  between  the  necks  of  the  teeth,  are 
completely  filled  by  muco-periosteal  tissue — 
the  inter-proximal  gum ;  the  contact  points  of 
the  teeth  by  their  apposition  protect  the  apices 
of  these  p3Tamids  of  inter-proximal  gum,. so 
that  food  in  mastication  camiot  impinge  on  the 
apex  but  only  on  the  sloping  sides,  off  ^^•hicll  it 
glides;  should  the  adjacent  teeth,  however, 
not  be  in  contact,  food  will  be  forced  on  to  the 
apex  of  the  p\Tamid  in  mastication  so  as  to 
flatten  it  dowTi,  and  will  become  impacted  be- 
tween the  teeth,  and  a  so-caUed  food  pocket  will 
be  formed  (see  Fig. 434).  The  inter-jDroximal  gum 
being  very  sensitive,  such  a  pocket  wUl  render 
the  teeth  useless  for  mastication ;  in  addition 
to  this  the  fermentation  of  tlie  impacted  food, 
if  it  be  acid,  may  cause  decalcification  and  caries 
of  the  adjoining  teeth,  or,  if  alkaline,  may  cause 
periodontitis  in  their  root-membranes ;  indeed 
some  cases  have  been  recorded  in  which  such 
a  pocket  is  believed  to  have  been  the  source 
of  a  septic  inflammation  of  the  gravest  char- 
acter (1). 

The  ideal  contact  between  teeth  is  like  that 

between  two  marbles  firmly  pressed  together, 

which    only   touch    each   other    at   one   small 

point.     If  the  areas  in  contact  are  flat  surfaces 

12 


instead  of  points,  the  inter-proximal  gum  will 
soon  be  no  longer  protected  :  food  driven  be- 
tween such  surfaces  sticks  fast  and  cannot  be 
easUy  removed,  and  acts  as  a  wedge,  causing 
slight  separation  of  the  teeth ;  more  food  is 
then  driven  down  during  mastication  on  the 
top  of  what  is  already  there,  forcing  it  on  to  the 
inter-proximal  gum,  which  it  flattens  down  and 
pushes  away  from  the  approximal  surfaces  of 
the  teeth ;  in  this  way  a  pocket  is  formed. 
Contact  points,  therefore,  to  be  effective  must 
be  quite  small — points  and  not  surfaces.  Again, 
the  full  medio-distal  diameter  of  the  tooth  must 
be  restored ;  if  this  is  not  done,  the  teeth  will 
not  be  in  sufficiently  firm  contact  with  each 
other  to  protect  the  inter-proximal  gum,  nor 


Fig.   434. 

1.  a.     Inter-proximal  space. 

b.  Inter-proximal  gum  driven  away  from  contact 

point :  commencing  food  pocket. 

c.  Healthy  inter-proximal  gum  in  position. 

2.  Approximal  surface.    Gum  driven  away  from  eon- 

tact  point — black  line  shows  original  position. 

3.  Inter-proximal  gum  in  position. 

(Feiesell  :  Dfntal  Cosmos.) 

will  the  formation  of  a  food  pocket  be  long 
prevented  in  any  case,  since,  if  tlie  diameters 
of  the  crowns  are  lessened,  the  teetli  come 
together  at  their  necks,  and  again  flat  surfaces 
are  in  contact ;  a  narrow  crevice  is  in  fact 
thereby  formed,  from  which  it  is  almost  im- 
possible to  dislodge  with  tongue  or  lips  such 
pieces  of  food  as  must  now  and  then  be  forced 
past  the  contact  points,  and  the  final  result  is 
a  food  pocket.  In  order,  therefore,  to  seQure 
restoration  of  function,  small  contact  points 
and  restoration  of  the  full  inter-proximal  space 
are  required  (3,  ^'ol.  ii,  p.  296)  (8). 

Methods 

The  procedures  by  ^hich  it  is  souglit  to 
arrest  caries,  to  prevent  its  recurrence,  and  to 
restore  the  function  of  the  tooth,  having  been 
discussed,  it  will  now  be  well  to  describe  the 


354 


methods   by  which   these   procedures  may   be 
carried  out.     The  general  priaciples  of  cavity 


Fig.  435. — Ivory's  Matrix  and  Retainer. 
{Messrs.Claudius  Ash,  Sons  <fc  Co.,  Ltd.) 

prejiaration  have  akeady  been 
described  (see  p.  344),  and  details 
are  dealt  with  in  the  descriptions 
of  the  filling  of  individual  cavities, 
and  of  the  uses  of  particular  filling- 
materials,  but  there  are  certain 
methods  of  such  universal  applica- 
tion that  they  may  well  come  under 
the  head  of  general  principles. 

Watertight  Fillings.  —  The 
methods  by  which  one  endeavours 
to  make  a  filling  watertight  are 
considered  in  those  chapters  where 
the  msertion  of  the  various  fiUing- 
materials  is  described.  Generally 
speaking,  it  may  be  said  that  in 
order  to  insert  a  watertight  filling 
the  cavity  must  be  thoroughly 
dried  with  hot  air,  since  no  pressure 
that  can  be  applied  is  sufficient  to 
expel  the  layer  of  moisture  between 
the  fiUmg-material  and  the  walls 
of  a  wet  cavity ;  the  drying,  how- 
ever, must  be  done  with  certain 
precautions,  since  it  is  stated  (3, 
vol.  i,  p.  193)  that  saliva  evaporated 
away  with  a  hot-air  syringe  leaves 
behind  it  a  deposit,  partly  crystal- 
line, partly  gummy,  which  pre- 
vents close  contact  of  tlie  filling- 
material  and  the  cavity  wall,  and 
is  itself  soluble  in  the  fluids  of  the 
mouth.  The  importance  of  this 
lies  m  the  fact  that  many  dentists 
excavate  the  cavity  (using  warm 
water  for  clearing  away  the  debris) 
before  adjusting  the  rubber-dam, 
drying  the  cavity,  and  putting  in 
the  filling.  Tliey  do  this  for  two 
reasons  :  firstly,  to  spare  the 
patient  as  much  as  possible  the 
disagreeable  sensation  caused  by 
the  rubber-dam  ;  and  secondly,  to 
avoid  constantly  blowing  the  debris 
from  the  cavity  about  the  operating  room,  as  is 
done  when  the  cavity  is  kept  dry  while  it  is  being 


excavated,  and  a  chip-syringe  used  for  clearing 
away  the  debris.  If  no  further  excavation  id 
found  necessary  after  the  adjustment 
of  the  rubber-dam,  it  is  as  well  to 
take  the  precaution  of  removing  the 
saliva,  by  washing,  before  the  cavity 
is  dried.  (Black  recommends  scrap- 
ing the  whole  internal  surface  with  a  sharp 
instrument  as  a  last  proceeding,  after  drying.) 


y 


Fio.  436.- 


1.  Flexible  key. 

2.  Shaping  tool. 

3.  Clamp  and  section  of  same.  6. 

4.  Clamp,  new  form  designed  by      7. 
W.  J.  Law.  {Me.9srs. 


6  7 

Lennox's  Matrix  and  Clamp. 

5.  Matrices  ready  for  bending  into 


shape. 
Matrix  ready  for  use. 
Wire  twister. 
Claudius  Ash,  Sons  &  Co.,  Ltd.) 


Restoration  of 
this,   a   durable 


Function. — In  order  to  effect 
and    strong    filling   that   will 


355 


® 


restore  the  shape  of  the  tooth  is  required.  The 
methods  by  which  durability  and  strength  are 
attained  are  dealt  with  elsewhere ;  but  as 
regards  restoration  of  shape,  at  least  in 
approximal  cavities  mvolving  the  occlusal 
surface,  there  are  some  points  to  be  now- 
considered.  There  are  two  classes  of 
approximo-occlusal  cavity — one  in  ^hich 
there  is  not  much  broken-down  enamel, 
though  the  amount  of  secondary  enamel- 
caries  may  be  considerable,  and  another 
in  which  so  much  of  the  enamel  has  broken 
down  that  the  tooth  has  been  allowed  to 
come  close  to  its  neighbour.  In  the  latter 
class,  in  order  to  restore  the  full  medio- 
distal  diameter  of  the  tooth,  the  crowns, 
either  before  or  during  the  filling  operation, 
must  be  separated  and  put  back  into  their 
original  positions.  The  methods  of  obtain- 
ing separation  have  already  been  described 
(see  p.  343). 

■  Whether  separation  has  been  made  or 
not,  in  order  to  insert  and  give  the  proper 
contour  to  an  approximal  filling  that 
involves  the  occlusal  surface,  the  use  of  a 
matrix  or  thin  metal  strip  applied  to  the 
tooth  so  as  to  supply  an  approximal  wall 
to  the  cavity  during  the  operation,  is 
desirable.  In  the  case  of  gold  or  cement 
fillings  the  matrix  is  merely  an  assistance, 
but  in  the  insertion  of  amalgam  fillings  it 
must  be  regarded  as  a  necessity,  as  with- 
out it  no  sufiicient  pressure  can  be  exerted 
3  on  the  amalgam  to  condense  and  contour 
it  properly. 

Matrices  for  use  with  amalgam  filluigs 
are  of  two  kinds.  In  one  the  metal  slip  is 
not  flexible,  but  is  of  tempered  steel,  and 
is  shaped  so  as  to  conform  to  the  shape 
of  the  approximal  surface  of  the  tooth ; 


punch  (.such  as  the  handle  of  an  old  excavator) 
on  a  lead  block,  according  to  the  method  sug- 
gested by  Arthur  (2).  This  kind  of  matrix  has 
one  serious  drawback,  which  is  that  owmg  to 
its  convexity  it  is  difficult  to  \\ithdraw  with- 
out injuring  the  filling,  while  the  amalgam  is  still 
soft. 

The  other  kind  of  matrix  is  in  more  general 
use :  it  consists  of  a  thin  strip  of  copper,  steel, 
or  German  silver,  which  is  either  fastened  round 
the  tooth,  as  for  instance  in  the  Ivory,  Hinni- 
ker,    Lennox,    Guilford,    Ladmore-Brunton,    or 


12  3  4 

Fig.  437. — The  Ladmore-Brunton  Matrix  and  Clamp,  with  flexible  key. 

1.  Key  for  adjusting,  with  steel  spiral  spring  between  the  upper  end  and  the 

handle. 

2.  Clamp  with  sliding  bar  parallel  with  the  screw. 

In  3  and  4  a  clamp  is  shown  in  which   the  sliding  bar  is  placed  at  right 
angles  to  the  hooks,  instead  of  imderneath  as  in  2. 

3.  Matrix  for  premolars  attached  to  the  clamp. 

4.  Matrix  for  molars  attached  to  the  clamp.     The  depth  of  this  matrix  is  given 

in  the  section. 

{Messrs.  Claudius  Ash,  Sons  dc  Co.,  Ltd.) 

of  these  a  set  may  be  kept  to  fit  every  tooth 
(as  the  Jack  matrices),  or  such  a  matrix  may 
be  struck  up  to  suit  the  case  in  hand  by 
punching    a    thin   steel    strip    with    a    convex 


[Fig.    438. — Spring  Matrices.      (Herbst's.) 

(Messrs.  Claudius  Ash,  Sons  cfc  Co.,  Ltd.) 

Herbst  matrices,  or  wedged  between  it  and  the 
neighbourmg  teeth,  as  in  the  Miller,  Crenshaw, 
and  Woodward.  In  all  these  an  attempt  is 
made  (in  most  of  them  by  the  tightening  action 
of  a  screw)  to  bring  the  metal  slip  in  close  con- 
tact with  the  cervical  edge  of  the  cavity,  while 
the  occlusal  edge  of  the  matrix  is  pushed  out  so 
as  to  be  in  contact  with  the  adjacent  tooth ; 
such  strips  can  be  easily  straightened  and  slipped 
out  without  disturbing  tlie  amalgam,  and  the 
filling  then  can  be  carved  to  shape ;  it  wUl  be 
found  that  except  in  the  cervical  third  of  the 
filling  a  good  deal  of  shaping  will  be  necessary. 
It  is  probable  that  with  each  and  all  of  these 
mstruments  good  work  may  be  done,  but  for 
mserting  amalgam  fillings  it  is  doubtful  if  they 
have  any  advantage  over  a  simjjler  form  of 
matrix  described  by  Clapp  (7),  for  the  fixmg  of 
which  a  ligature  only  is  used.  This  is  made  in 
the  following  way.     (See  Fig.  439.) 

Out  of  a  sheet  of  German 
sUver  of  about  35  to  38 
gauge  a  strip  is  cut,  long 
enough  to  encircle  half  the 
tooth  and  deep  enough  to 
reach  from  the  cervical 
edge  to  the  occlusal  sur- 
face ;  it  is  shaped  to  fit  just 
over  the  cervical  edge  of 
the  cavity,  and  the  occlusal 
edge  is  also  trimmed  do\vn 
approximately  to  the  bite, 
as  any  over-fillhig  of  the 
cavity  at  this  part  renders 
the  safe  removal  of  the 
matrix  more  difficult.  In 
the  lower  or  cervical  mar- 
gin of  the  strip  two  small  holes  are  punched, 
one  at  each  end,  and  through  these  a  ligature 
is  passed  so  as  to  lie  on  the  outer  surface 
of   the   matrix.     The   strip    is    then    adjusted. 


356 


and  the  ligature  firmly  tied  round  the  tooth  | 
and  knotted  so  as  to  hold  the  cervical  edge 
of  the  matrix  m  position  (if  necessary  it  may 
be  assisted  in  this  by  the  insertion  of  a  plug 
of  gutta-percha,  or  a  wedge  of  wood,  or  pledget 
of  cotton-wool,  between  the  matrix  and  the 
neck  of  the  adjacent  tooth).  The  loose  ends  of 
the  ligature  are  then  wound  round  and  round 
the  tooth  so  as  to  hold  the  matrix  firmly  in 
contact  with  the  edges  of  the  cavity  as  far  as 
possible  up  the  sides  of  the  tooth ;  and  finally 
the  occlusal  portion  is  pressed  outwards  with 
a  ball-ended  plugger.  so  as  to  give  the  desired 
bulk  to  the  occlusal  portion  of  the  filling.  When 
the  filling  is  completed  the  ligatures  are  first 
cut  and  removed ;  the  matrix  can  then  be 
straightened  out  and  withdrawn  laterally.     It 


Fig.  439.— The  Clapp  Matrix. 
Dentistry.) 


(Kirk  :  Operative 


is,  of  course,  possible  to  leave  it  tied  round  the 
tooth  uiitU  the  amalgam  is  quite  set,  or  even  for 
twenty-four  hours,  but  this  is  in  most  cases 
quite  unnecessary  if  due  regard  is  paid  to  the 
occlusion. 

In  fitting  a  matrix  to  an  approximal  cavity, 
it  must  be  borne  in  mind  that  the  end  m  view 
is  to  fit  the  matrix  so  closely  to  the  edges  of 
the  cavity  ui  its  gmgival  half  that  little,  if  any, 
finishing  shall  be  required  on  this  jjart  of  the 
filling  ;  the  occlusal  half  and  its  edges  are  easily 
accessible  when  the  matrix  is  removed,  and  can 
then  be  shaped  and  .smoothed.  Any  attempt 
to  bring  a  .slip  matrix  into  accurate  contact 
with  the  occlusal  half  of  the  approximal  walls 
renders  it  more  difficult  to  get  contact  with  their 
gingival  half,  and  it  is  a  special  merit  in  the 
Clapp  matrix  (as  also  m  the  Ivory)  that  it  can 


be  adjusted  and  firmly  fixed  at  the  cervical 
edge  before  any  attempt  is  made  to  fix  the 
occlusal  portion. 

A  double  spring  matrix,  the  Herbst,  has  also 
been  recommended,  which  enables  one  to  insert 
two  opposed  approximal  fillings  at  one  sitting ; 
but  the  effective  carrymg  out  of  this,  either  with 
the  Herbst  or  any  other  form  of  matrix,^  is  a 
most  difficult  operation,  likely  to  result  in 
failure,  smce  the  heavy  pressure  necessary  to 
condense  the  amalgam  in  one  fillmg  tends  to 
press  the  other  out  of  shape.  It  is  better 
to  finish  and  polish  one  filling  and  then  insert 
the  opposmg  one  at  a  future  visit.  Makeshift 
matrices,  such  as  a  strip  of  steel  or  dividmg 
file  fixed  in  position  with  a  wooden  wedge,  may 
be  effective  in  skilled  hands  or  in  simple  cases, 
but  as  a  rule  the  short  time  required  to  adjust 
a  matrix  properly  is  in  the  end  time  saved. 

VII.— FILLING  MATERIALS 

The  qualities  that  are  necessary  ui  an  ideal 
filling  material  are  : 

(1)  Edge-strength  and  hardness; 

(2)  Resistance  to  w  ear  and  chemical  action ; 

(3)  That  it  shall  not  alter  in  volume  or  shape ; 

(4)  Ease  in  working  ; 

(5)  That  it  shall  be  it.self  a  good  colour,  and 

shall  not  discolour  the  tooth  substance  ; 

(6)  That  it  shall  be  of  low  conductivity  for 

heat,  and  as  far  as  possible  non-irritant. 

Gold   (see  Chaps.  XXI,  XXII) 

Cohesive  gold,  introduced  in  1851,  must  still 
be  considered  the  best  fiUuig-material  at  com- 
mand in  suitable  cavities.  Its  edge-strength  is 
very  great,  so  much  so  that  it  can  be  slightly 
bevelled  over  the  cut  surface  of  the  enamel  at 
the  cavo-surface  angle  without  fear  of  makmg 
the  edge  of  the  filling  itself  too  weak,  and  in 
this  way  gives  great  strength  to  the  enamel 
margin ;  with  no  other  filling-material  can  this 
be  safely  done.  Its  hardness,  though  not  so 
great  as  that  of  porcelain,  is  sufficient  to  with- 
stand the  stress  of  mastication,  and  though  in 
inter-proximal  fiUings  there  will  be  some  wearmg 
down  of  the  contact  point,  this  is  not  enough  to 
interfere  with  the  usefulness  of  the  filling.  It 
is  unaffected  by  the  fluids  of  the  mouth,  and  does 
not  tend  in  any  way  to  alter  in  shape  after 
insertion. 

It  is  held  by  Black  (3,  vol.  ii,  p.  225)  that 
among  its  advantages  must  be  counted  the  fact 
that  gold  hammered  into  a  filling  ijosssesses  a 
considerable  power  of  sustaining  pressure  with- 
out altering  in  shape  ;  and  that  since  the  dentine 
into  which  it  is  inserted  is  a  very  elastic  sub- 
stance, the  result  is  that  a  skilful  operator  can 

'  The  Crensliaw  matrices  are  not  meant  to  be  ixsed 
in  this  way  (12). 


357 


so  wedge  iii  the  gold  as  to  cause  it  to  be  gripped, 
so  to  speak,  by  the  elastic  dentine ;  and  that  in 
this  way  a  tighter  filling  can  be  made  witli  gold 
than  with  any  other  material.  In  fact,  just 
as  the  compression  of  a  cork  causes  it  to  be 
held  tightly  in  a  bottle,  so  the  compression 
of  the  dentine  causes  the  filling  to  be  held 
tightly  in  the  cavity.  Gold  can  be  worked 
cohesively  because  it  has  the  property  of  being 
welded  cold. 

In  other  qualities  cohesive  gold  is  not  so  good. 
Its  colour  makes  it  conspicuous  in  the  incisors, 
and  in  them,  therefore,  for  aesthetic  reasons 
porcelain  inlays  and  the  sUicate  cements  have 
largely  replaced  it.  It  is  a  good  conductor  of 
heat  and  should  not,  therefore,  be  placed  in 
proximity  to  the  pulp,  but  this  bad  quality  can 
be  neutralized  by  mserting  a  layer  of  oxy- 
phosphate  cement  on  the  floor  of  the  cavity  and 
allowing  it  to  harden  before  inserting  the  gold 
filling.  It  cannot  be  said  to  possess  ease  of 
working,  either  for  the  patient  or  for  the 
operator,  and  a  slight  mistake  on  the  part  of 
the  latter  is  sufficient  to  impair  the  lasting 
qualities  of  the  filling. 

In  order  to  condense  gold  sufficiently, 
repeated  blow.s  of  suitable  strength  must  be 
delivered,  and  it  is  pointed  out  by  Black 
(3,  vol.  ii,  p.  238)  that  the  resistance  offered 
by  the  tootli  is  to  be  considered,  as  well  as  the 
force  of  impact  of  the  mallet ;  the  periodontal 
membrane  is  thicker  in  youth  than  iii  adult  life, 
and  acts  as  a  cushion,  by  which  much  of  the 
force  of  the  blo\\'  is  absorbed,  and  this  makes 
the  condensing  of  gold  fillings  more  difficult  in 
young  patients.  It  Ls  also  believed  by  some 
operators  that  the  enamel  in  the  teetli  of  young 
persons  is  not  of  sufficient  strength  to  withstand 
the  impaction  of  cohesive  gold  against  it  without 
being  cracked,  or  checked,  and  that  this  is  a 
common  cause  of  the  failure  of  gold  fillings ; 
and  lately  this  belief  in  the  want  of  strength 
of  recently  erupted  enamel  has  received  con- 
firmation from  the  investigations  of  Pickerill 
(19,  pp.  90  et  seq.)  on  the  hardness  of  enamel.  It 
has,  however,  been  demonstrated  by  Black  that 
far  too  mucli  importance  has  been  attached  to 
the  age  and  appearance  of  enamel,  juvenile  or 
adult,  as  an  indication  of  its  strength,  and  that 
probably  all  enamel  is  strong  enough  to  with- 
stand the  force  necessary  for  the  adaptation  of 
gold  (4)  No  limit  of  age.  therefore,  can  be  laid 
down,  but  it  may  be  stated  generally  that 
chUdren  are  not  good  subjects  for  cohesive  gold 
filling,  on  account  of  the  tediousness  of  the 
operation,  and  of  the  thicker  periodontal  mem- 
brane and  larger  tooth  pulp. 

Various  forms  of  crystal  gold  or  mat  gold 
have  been  put  on  the  market,  and  excellent 
fillings  have  been  made  with  them,  but  they  do 
not  keep  well. 


Non-cohesive  Gold. — This  form  of  gold  was  the 
first  employed,  and  was  for  a  long  time  the  only 
form  in  -vihich  gold  was  used ;  a  filling  can  be 
made  with  it  that  is  so  firmly  pressed  against 
the  cavity  walls  as  to  be  watertight,  and 
capable  of  withstanding  very  well,  in  suitable 
cavities,  the  wear  and  tear  of  mastication. 
It  is  not  possible,  however,  to  form  con- 
tours, such  as  are  necessary  in  approximal 
cavities,  mth  this  form  of  gold,  and  since 
the  advent  of  cohesive  gold,  the  non-cohesive 
fillings  have  been  very  generally  given  up. 
Non-cohesive  gold,  however,  is  still  used  by 
many  operators  for  filling  the  cervical  or 
buccal  portion  of  approximal  cavities,  as  much 
as  a  third  of  the  filling  being  sometimes  so 
constructed ;  in  this  portion  it  is  not  exposed  to 
attrition  and  need  not  be  to  any  great  extent 
contoured. I 

Tin 

Tin  in  the  form  of  foil  can  be  used  in  the  same 
way,  and  in  the  same  class  of  cavity,  as  non- 
cohesive  gold.  It  possesses  much  the  same 
advantages  and  drawbacks  as  the  latter ;  it 
is,  hoM'ever,  rather  softer,  and  for  this  reason, 
though  easy  to  adapt  to  the  cavity  walls,  it  does 
not  wear  so  well.     Its  colour  also  is  objectionable. 

The  two  materials,  tin  and  non-cohesive  gold, 
may  be  combined,  a  sheet  of  tinfoil  being  folded 
between  two  sheets  of  gold.  Used  in  the  same 
way  as  non-cohesive  gold,  this  mixture  becomes 
very  hard  and  durable,  and  has  excellent  wearing 
and  tooth-saving  properties.  But  tin,  and  tin 
and  gold,  are  as  limited  in  their  application  as 
non-cohesive  gold,  as  they  are  not  strong  enough 
for  forming  contours. 

Amalgams  (see  Chap.  XXIII) 

Under  this  name  are  grouped  those  alloys 
that  contain  mercury  and  have  the  property  of 
setting  or  becoming  hard  after  their  formation. 
They  may  be  divided  into  two  groups — those 
containing  in  addition  to  the  mercury  only 
copper,  or  large  quantities  of  copper,  and  those 
containing  mostly  silver  and  tin. 

The  silver-tin  alloys  are  permanent  fillings  in 
so  far  as  they  are  not  subject  to  solution  or  -wear 
in  the  mouth  to  any  harmful  extent ;  they  are 
a  bad  colour,  but  do  not  discolour  tooth  sub- 
stance when  it  is  sound ;  they  are  good  con- 
ductors of  heat,  but  are  non-irritant ;  they  are 
easy  to  work  and  to  adapt  to  the  cavity  walls; 
their  edge-strength  and  crushing  strength  are 
sufficient,  if  care  is  taken  so  to  sliape  the  enamel 
edges  of  the  cavity  that  no  thin  edge  of  the 
filling-material  shall  be  left.  On  account  of  all 
these  merits  they  are  very  largely  used  for 
fillings  in  the  back  of  the  mouth,  but  owing  to 
their  bad  colour  they  are  not  suitable  for  filling 
incisors.     It  is  stated  by  Black  that  the  chance 


358 


of  finding  a  good  light-coloured  amalgam  is 
remote,  since  both  zinc  and  gold,  the  metals 
that  give  the  best  colour  results,  have  a  very 
harmful  effect  on  the  other  properties  of  the 
alloy.  The  question  whether  they  discolour 
the  tooth  substance  has  been  investigated  by 
A.  Witzel  (27),  and  the  conclusion  arrived  at  by 
him  from  the  study  of  extracted  teeth,  is  that 
neither  copper  nor  silver-tin  amalgams  discolour 
dentine  in  which  no  softening  has  taken  place, 
unless  the  dentinal  fibrils  in  it  are  dead,  either 
from  death  of  the  pulp  or  from  having  their 
communication  with  the  pulp  severed.  If  the 
filling  leaks  discoloration  is  produced ;  the 
stain  is  probably  a  sulphide  of  silver  or  of 
copper,  produced  by  the  action  of  the  sulphide 
of  hydrogen  in  the  saliva  on  the  fiUmg-material, 
and  it  is  only  in  a  leaking  filling  that  this  can 
be  formed  next  the  dentine. 

The  worst  defect  in  silver-tin  amalgams  is 
that  they  do  not  usually  preserve  their  shape 
unaltered  after  being  inserted.  In  this  respect 
their  behaviour  is  inconstant ;  that  is,  a  filling 
made  from  a  certain  alloy  may  be  seen  some 
time  afterwards  in  the  mouth  with  gaping  and 
curled-up  edges,  whilst  another  of  about  the 
same  age  from  the  same  alloy  may  be  found  in 
good  condition.  The  cause  of  this  alteration 
in  shape,  shrinkage,  expansion,  spheroiding,  or 
whatever  it  may  be,  has  been  diligently  searched 
for  by  many  inquirers,  but  it  is  only  possible 
here  to  allude  to  a  few  of  the  conclusions  arrived 
at.  It  has  been  established,  chiefly  by  the 
labours  of  Black  (5),  that  the  inconstancy  in  the 
behaviour  of  any  silver-tin  alloy,  though  in- 
serted under  the  same  conditions,  may  be 
accounted  for  by  the  fact  that  these  alloys  are 
affected,  as  regards  their  shrinkage  and  expan- 
sion on  setting,  by  the  temperature  to  which 
they  are  exposed  after  being  cut  up  from  the 
mgot ;  an  alloy  f reslily  cut  from  the  ingot  and 
ready  for  mixing  he  calls  a  fresh  alloy,  and  one 
wliich  has  been  exposed  to  a  temperature  of 
212°  F.  for  fifteen  minutes  he  calls  a  fully 
"  aged  "  or  "  annealed  "  alloy  (the  same  effect 
is  obtained  by  exposure  to  a  lower  temperature 
for  a  longer  period).  The  fresh  and  the  an- 
nealed alloy  behave  quite  differently  as  regards 
shrinkage  and  expansion  on  setting ;  thus  an 
alloy  that  expands  on  setting  when  fresh  may 
shrink  considerably  on  setting  when  annealed 
before  mixing,  and  it  is  plain  that  much  of  the 
inconstant  behaviour  of  silver-tin  amalgams  may 
be  thus  accounted  for,  since  the  annealing  may 
go  on  as  a  gradual  process  in  the  dentist's  room. 
Incidentally  Black  discovered  that  silver-tin 
alloys  possess  to  a  marked  extent  a  quality  that 
he  called  "flow",  which  causes  them  to  yield 
continually  under  a  given  fixed  pressure,  this 
quality  apparently  depending  on  the  presence 
of  the  tin.     Now  it  seems  likely  that  the  curled- 


up  or  gapmg  edges  of  old  amalgam  fiULngs  must 
be  accounted  for  in  some  other  way  than  by 
the  shrinkage  or  expansion  of  the  fUling.  Were 
this  the  cause  these  edges  would  be  seen  earlier 
in  the  life  of  the  filling,  since  it  has  been  shown 
by  Black  that  the  amount  of  shrinkage  that 
goes  on  after  a  few  months  is  so  small  as  to  be 
a  negligible  quantity.  It  has,  therefore,  been 
suggested  that  the  cause  may  be  found  in  this 
property  of  "flowing".  The  muscles  of  the 
jaw  can  compress  food  with  great  force,  more 
than  sufficient  to  cause  "  flow  "  in  many  of  the 
amalgams  used ;  this  means  that  each  time 
sufficient  pressure  is  exerted  on  one  part  of  the 
filling,  the  amalgam  is  driven  towards  that 
surface  where  the  pressure  is  least.  In  this 
way  it  is  plain  that  an  approximal  fUling,  for 
instance,  might  be  easily  driven  out  of  a  cavity 
by  pressure  on  the  coronal  portion ;  it  is  also 
conceivable  that  such  pressure  might  cause  the 
gaping  or  curling  up  of  the  edges  seen  in  old 
amalgam  fillmgs  in  the  mouth.  It  is  pointed 
out  by  Cass  Grayston  (9,  p.  639)  that  experi- 
mental amalgam  fillings  made  in  extracted  teeth 
do  not  exhibit  this  appearance,  even  after  many 
years,  and  this  would  seem  to  corroborate  the 
suggestion. 

These  experiments  of  Black  are  in  one  sense 
very  disappointing ;  they  have  not  resulted  in 
a  fixed  formula  i  for  a  silver-tin  alloy  that  after 
annealing  will  neither  contract  nor  expand  on 
setting,  and  that  will  possess  sufficient  crushing 
strength  and  absence  of  flow — a  formula  that 
would,  in  fact,  give  an  amalgam  that  if  properly 
mixed  and  inserted  would  be  unalterable ;  but 
they  have  been  of  enormous  service  in  directing 
the  attention  of  the  profession  and  the  dental 
manufacturers  to  the  drawbacks  of  amalgams 
and  to  the  methods  of  overcoming  them. 

It  seems  to  be  generally  admitted  that  the 
best  results  with  silver-tin  alloys  are  to  be  got 
by  the  use  of  an  alloy  in  the  manufacture  of 
which  due  account  has  been  taken  of  Black's 
experiments,  and  in  the  insertion  of  which  his 
methods  of  handling  and  cavity  preparation 
have  been  followed,  since  these  have  been 
designed  to  neutralize  as  far  as  possible  the 
faults  found  by  him  to  be  inlaerent  in  the 
material.  Though  an  ardent  supporter  of  gold 
as  the  best  fUling-material,  Black  himself  thinks 
tliat  a  well-inserted  amalgam  fLlImg  is  but  little 
inferior,  except  in  appearance,  to  a  gold  filling. 

Copper  Amalgam,  or  copper  amalgam  with  a 
small  percentage  of  tin,  has  two  great  merits  : 
it  is  easily  worked  and  it  does  not  shrink  or 
expand  when  setting ;  it  is  also  very  hard  and 
does  not  "  flow  ",  i.  e.  does  not  yield  to  long- 

'  This  is  attributed  by  Black  (3,  vol.  ii,  p.  310)  to 
the  fact  that  such  a  formula  can  only  bo  given  for  pure 
metals,  and  that  the  expense  of  getting  pure  metals 
is  prohibitive. 


359 


continued  pressure.  Ifc  is  not,  however,  inde- 
structible in  the  mouth ;  it  gradually  wastes 
away,  « ith  varying  rapidity  in  different  mouths, 
and  cannot,  therefore,  be  regarded  as  a  perma- 
nent filling  ;  this  wasting  seems  to  proceed  ^\ith 
greater  rapidity  at  the  cervical  edges  of  approxi- 
mal  fillings  than  elsewhere,  and  the  attempt  to 
make  a  permanent  approximal  filling  ^^'ith 
copper  amalgam  generally  results  after  a  longer 
or  shorter  interval  in  penetrating  caries  at  the 
cervical  edge,  and  an  exposed  pulp.  In 
approximal  cavities  it  should  not  be  used  except 
as  a  temporary  filling,  as  in  the  deciduous  molars. 
In  crown  cavities,  where  the  wasting  can  be 
seen,  and  is  of  less  importance,  as  not  causing 
loss  of  medio-distal  diameter,  it  may  often  be 
placed  with  advantage.  Like  the  silver-tin 
alloys  it  is  itself  a  bad  colour,  and  also  discolours 
the  tooth-substance,  though  probably  not  in 
those  parts  where  the  tissues  are  not  decalcified, 
and  contain  living  matter  in  the  tubules ;  it  is 
a  non-irritant,  but  is  a  good  conductor  of  heat, 
so  that  it  is  liable  to  cause  irritation  from 
thermal  changes.  Under  copper  amalgam  fill- 
ings, dentine  of  a  hard  leathery  consistency  and 
deeply  stained  is  found,  in  which  caries  has 
seemingly  been  arrested,  and  one  is  justified  in 
assuming  that  in  many  cases  this  dentine  was 
soft  and  actively  carious  when  the  filling  was 
put  in;  the  same  thing  is  said  to  occur  under 
amalgams  containing  much  silver.^  It  is  as 
yet  unknown  whether  this  arrest  is  due  to 
chemical  causes,  such  as  the  formation  of  copper 
and  silver  sulphides,  or  whether  it  is  caused  by 
the  mechanical  action  of  the  filling  in  preventing 
the  lodgement  of  food  in  the  cavity. 

Cements  (see  Chap.  XXIII) 
All  the  oxy-phospliate  and  oxy-chloride 
cements  are  pervious  to  fluids,  and  are  not  (^^ith 
the  possible  exception  of  oxy-chloride  of  zinc) 
an  effective  barrier  to  the  entrance  of  micro- 
organisms (25) ;  nevertheless,  their  power  of 
arresting  caries  in  a  tooth  is  good.  In  this 
respect  there  does  not  seem  to  be  any  difference 
between  them,  though  some,  such  as  oxy- 
phosphate  of  copper  and  oxy-chloride  of  zinc, 
have  certain  antiseptic  qualities,  and  if  caries 
progresses  not  at  the  margin  of  the  filling,  but 
underneath  it,  in  a  cavity  into  which  cement 
has  been  put,  one  may  assume  that  the 
cause  lies  in  defective  cavity  preparation. 
They  all  waste  away  when  exposed  to  the 
fluids  of  the  mouth,  this  wasting  taking  place 
more  rapidly  in  the  less  exposed  portion  of  the 
fUling,  as  at  the  cervical  edge,  and  this  defect 
renders  them  unsuitable  for  any  but  temporary 
fillings.     The  use  of  them  is  especially  to  be 

'  It  is  suggested  by  Cass  Grayston  that  the  zinc, 
put  into  amalgams  to  improve  their  colour,  does  away 
with  this  preservative  action  (9,  p.  637). 


avoided  on  approximal  surfaces  in  molars  and 
premolars,  as  they  neither  preserve  the  full 
medio-distal  diameter  of  the  tooth,  nor  protect 
from  caries  the  cervical  margin,  the  most 
vulnerable  part ;  should  it  be  necessary  to  use 
them  in  this  position,  it  is  an  excellent  plan  to 
line  thickly  the  cervical  wall  -with  a  permanent 
amalgam  before  inserting  the  cement,  as  this 
protects  the  cervical  wall  to  a  certain  extent. 

The  rapidity  with  which  cements  waste  varies 
in  different  mouths ;  as  a  rule  the  process  is 
most  rapid  in  those  mouths  most  prone  to  caries. 
The  oxy-phosphates  are  the  only  material  that 
can  be  successfully  used  to  support  weak 
enamel ;  this  quality  they  owe  to  their  adhesive- 
ness and  to  the  fact  that  they  do  not  shrink  or 
expand. 

Oxy-pJiospIiate  of  Zinc  is  useful  as  a  temporary 
filling;  to  get  the  best  results  the  rubber-dam 
must  be  used,  as  dryness  of  the  cavity  wall,  and 
protection  from  moisture  of  the  cement  while 
setting,  are  necessary  conditions.  Though  a 
bad  conductor  of  heat  it  is  a  chemical  irritant, 
and  should  not  be  placed  very  close  to  a  live 
pulp.  Owing  to  its  lack  of  transparency  it 
can  scarcely  ever  be  made  to  resemble  the  tooth 
substance  in  appearance.  Its  largest  field  of 
usefulness  is  for  the  Iming  of  cavities  and  for 
the  setting  of  hilays  and  crowns. 

Oxy-chloride  of  Zinc. — This  cement  has  anti- 
septic properties  :  it  can  act  as  a  barrier  to  the 
entrance  of  micro-organisms,  at  any  rate  for  a 
considerable  time  (25),  and  does  not  become  so 
rapidly  septic  in  the  mouth  as  does  oxy-phos- 
phate  of  zinc  ;  in  every  other  respect,  however, 
it  is  slightly  inferior  to  the  latter,  and  it  is  now 
not  often  used  except  for  filling  the  pulp- 
chamber  when  the  root-canals  are  filled  with 
gutta-percha. 

Oxy-phosphale  of  Copper.— With  the  exception 
i  of  colour  (for  it  is  quite  black),  this  cement  has 
all  the  good  qualities  of  oxy-phosphate  of  zinc ; 
the  claim  is  also  made  that  it  has  the  same 
preservative  effect  on  the  tooth  substances  as 
is  attributed  to  copper  amalgam. 

Permanent  fiUiiigs  cannot  be  made  with  it, 
but  it  is  much  used  by  some  operators  for  fiUing 
the  deciduous  teeth. 

Silicates. — Tliese  cements  have  not  been  long 
enough  in  use  to  permit  definite  knowledge  to 
be  gained  as  to  their  qualities.  Generally 
speakmg  their  tooth-saving  .  properties  are 
inferior  to  those  of  the  oxy-phosphates.  With 
silicates  caries  is  more  likely  to  recur  under- 
neath the  fiUing  and  at  the  cavity  margin, 
probably  because  it  is  much  more  difiicult  to 
secure  a  good  joint  between  the  filling  and  the 
cavity  wall.  None  of  the  cements  on  the 
market  are  adhesive,  and  some  of  them  at  any 
rate  shrink  considerably  on  settmg ;  some  of 
them  also  become  discoloured  after  a  period  in 


360 


the  mouth.  There  are  two  points,  however,  in 
which  they  are  superior  to  any  oxy-phosphate  : 
firstly,  owing  to  their  translucency  a  very  exact 
imitation  of  the  tootli  substance  can  be  made, 
and  so  a  filling  is  secured  that  is  very  difficult 
to  detect  as  long  as  its  smooth  surface  is  re- 
tamed ;  secondly,  they  do  not  waste  away  as 
rapidly  as  the  oxy-phosphates,  so  that  contours 
can  be  made  with  them,  though  in  this  connec- 
tion it  should  be  stated  tliat  they  are  not  hard 
enough  to  retain  for  any  length  of  time  the  small 
point  of  contact  to  be  desired  m  an  approximal 
filling.  As  regards  edge-strength  they  are 
inferior  to  the  oxy-phosphates.  They  aie  non- 
conductors but  are  irritant,  and  many  of  them 
cont«,ui  arsenic ;  cases  have  been  observed  in 
which  death  of  the  pulp  has  followed  the  insertion 
of  a  small  silicate  fiUmg,  and  it  is  therefore 
best  in  deep  cavities,  to  place  under  them  an 
oxy-phosphate  of  zinc  lining.  As  far  as  one 
can  judge  at  present  the  fillings  of  this  material 
camiot  be  regarded  as  permanent  work. 

Inlays  (see  Chaps.  XXIV,  XXV) 

High-fusing  porcelam,  fused  so  as  to  fit  the 
cavity,  and  cemented  in  place  with  oxy-phos- 
phate of  zinc,  is  a  fiUing-material  with  most 
excellent  qualities.  From  an  aesthetic  point  of 
view  it  is  far  beyond  all  other  materials  except 
the  silicates.  It  is  hard,  and  strong  enough  to 
form  contours,  is  unalterable  in  the  mouth,  and 
is  a  bad  conductor  of  heat.  It  has,  however, 
two  drawbacks,  which  have  interfered  with  its 
more  general  adoption  :  one  is  the  difficulty 
that  sometimes  exists  in  gettmg  adequate 
retention  for  the  filling,  and  the  other  the  diffi- 
culty in  working  the  material,  for  the  fitting 
and  making  of  a  good  fused-porcelam  inlay  is 
a  matter  in  which  much  skill  is  required. 
^Vhen  inserted,  the  life  of  the  filling  depends 
entirely  on  the  permanence  of  the  cement  with 
which  it  is  fixed ;  this  fact  has  not  proved  as 
serious  as  was  at  first  anticipated,  since  the 
dissolution  of  the  cement,  after  a  certain  time, 
proceeds  very  slowly,  so  much  so  that  some 
observers  believe  that  the  depth  to  which  the 
cement  will  dissolve  away  does  not  exceed  the 
width  of  its  exposed  surface.  It  is  certain  that 
inlays  have  been  retained  without  recurrence  of 
caries  in  some  cases  for  over  fifteen  years  (6) ; 
this  should  justify  their  being  regarded  as 
permanent  fillings ;  and  though  to  attain  this 
result  in  every  case  may  be  beyond  reasonable 
expectation,  they  must  be  regarded  as  the  best 
material  to  use  when  colour  has  to  be  taken  into 
consideration.  Inlays  are  also  made  of  low- 
fusing  porcelain  and  used  with  success,  but  the 
surface  is  more  liable  to  become  etched  and  dull 
in  the  mouth.  Equally  good  results  can  be 
got  from  Ball's  and  Guttmann's  inlays,  but  as 
the  cavity  must  be  made  to  fit  them  instead  of 


their  being  made  to  fit  the  cavity,  they  are  of 
more  limited  application. 

Inlays  can  also  be  made  of  metal,  and  since 
the  introduction  of  the  pressure-casting  process 
by  Taggart,  gold  inlays  have  been  widely  used. 
By  this  process,  which  enables  one  to  reproduce 
in  gold  an  exact  copy  of  a  wax  model  of  the 
cavity,  very  well-fitting  inlays  can  be  obtained, 
and  contours  can  be  reproduced  more  easily 
than  with  porcelain.  The  gold  inlay  is  superior 
to  the  porcelain  in  edge-strength,  and  though 
not  so  hard,  it  is  not  brittle,  and  is  therefore 
not  liable  to  fracture.  Owing  to  its  malleable 
nature  the  gold  can  be  burnished,  while  the 
cement  is  setting,  agamst  the  cavity  edges, 
which  are  left  slightly  bevelled  to  facilitate  the 
process,  and  in  this  way  it  is  possible  to  prevent 
any  exposure  of  the  cement  to  the  fluids  of  the 
mouth.  This  power  of  protecting  the  cement 
used  for  its  setting  is  obviously  a  most  valuable 
one,  and  justifies  one  in  thmking  that  m  the 
case  of  this  inlay  no  failure  from  solution  of  the 
cement  is  to  be  feared,  so  that  it  can  be  made  a 
permanent  and  unalterable  filling. 

In  preparing  a  cavity  for  a  gold  or  porcelain 
inlay,  undercuts  must  be  altogether  removed, 
for  obvious  reasons,  and  it  is  probable  that  it 
is  to  this  free  opening-up  of  the  cavity  that  is 
due  the  absence  of  recurrence  that  has  been 
noticed  in  connection  with  porcelain  inlays,  and 
that  it  is  hoped  will  also  belong  to  gold  inlays. 
There  is  very  little  doubt  that  failure  to  remove 
decalcified  enamel  or  dentme,  and  in  some  cases 
failure  to  extend  the  cavity  so  that  its  edges 
shall  be  suitably  placed,  are  the  chief  causes  of 
recurrence  of  caries ;  now  in  these  two  respects, 
and  especially  in  the  former,  owing  to  the 
necessity  for  removing  undercuts  a  cavity 
prepared  for  an  inlay  is  likely  to  be  superior  to 
one  prepared  for  a  filling  by  the  same  operator, 
and  so  the  power  of  retaining  undercuts  that  at 
first  sight  appears  to  give  strength,  and,  there- 
fore, to  be  a  point  in  favour  of  amalgam  or 
cement  or  of  the  two  combined,  cannot  really 
be  regarded  as  an  inimixed  advantage. 

There  is  another  method,  however,  of  using 
inlays,  which  allows  undercuts  to  be  retained  : 
the  cavity  can  be  first  excavated  and  filled  with 
cement,  and  after  this  has  hardened  a  sufficient 
quantity  of  it  may  be  cut  out,  and  an  inlay  made 
and  cemented  in  to  replace  it ;  or  the  undercuts 
may  be  filled  with  cement  and  the  cavity  thereby 
made  of  suitable  form  for  the  insertion  of  an 
inlay. 

Gutta-percha  (see  Chap.  XXIII) 

Even  the  so-called  permanent  gutta-perchas 
are  not  permanent  fillings,  as  they  are  not 
hard  enough  to  withstand  the  pressure  of 
mastication  and  the  friction  of  food :  in 
places  where  they  are  least  exposed  to  these, 


361 


they  may  last  a  long  time.  Gutta-percha, 
though  it  becomes  foul  in  the  mouth  (or  perhaps 
for  this  reason,  since  it  is  then  probably  alkaline 
in  reaction),  has  good  powers  of  arresting  caries, 
and  this  in  spite  of  the  fact  that  a  watertight 
joint  is  rarely  attained  with  it.  It  swells  in  the 
presence  of  moisture,  and  is  believed  in  this 
way  sometimes  to  cause  the  fracture  of  a  cavity 
wall,  if  it  is  confined  underneath  an  unyielding 
filling. 

VIII. —  THE  APPROPRIATE  FILLING  IN 
CAVITIES  OF  VARIOUS  DEGREES  IN 
DIFFERENT  TEETH  AT  DIFFERENT  AGES 

Incisors. — In  dealing  with  the  teeth  of  young 
people  it  must  be  borne  in  mind  that  root- 
fillings  put  into  teeth  whose  roots  are  incom- 
pletely formed  are  rarely  successful ;  three 
to  five  years,  generally  speaking,  are  required 
after  the  eruption  of  a  tooth  to  complete  the 
formation  of  its  roots.  Great  care  should, 
therefore,  be  taken  to  preserve  the  vitality  of 
the  pulp  in  young  patients ;  and  in  susceptible  j 
mouths  the  most  constant  and  regular  examina- 
tion is  required  in  order  that  cavities  may  be 
dealt  \\itli  before  they  have  attained  nuich 
depth. 

Approximal  caries  in  the  mcisors  may  appear 
as  early  as  the  eighth  year.  With  such  young 
patients  a  gold  filling  is  generally  impossible,  and 
oxy-pliosphate  of  zinc  or  the  so-called  permanent 
gutta-percha  should  be  used ;  if  the  cavity  is 
deep  and  can  be  made  of  a  strongly  retentive 
shape,  the  latter  will  be  the  most  durable  filling, 
but  it  should  be  inspected  at  mtervals  to  see 
if  it  is  wearing  out  unduly  fast.  Well -inserted 
gutta-percha  fillings  will  last  for  years.  Cement 
fillings,  if  it  has  been  possible  to  excavate  the 
cavity  properly,  may  be  expected  to  last  about 
two  years  before  they  need  replacement.  In 
all  cases  the  cavities  should  be  opened  from  the 
lingual  side,  and  as  little  as  possible  of  the  labial 
enamel  removed ;  when  the  patient  is  older 
these  fillings  can  be  replaced  with  something 
permanent.  It  is  a  good  plan,  especially  if  the 
patient  is  a  boy,  to  place  amalgam  fillings  with 
a  thick  cement  lining  into  these  cavities ;  such 
fillings  often  preserve  the  tooth  very  effectively, 
and  they  can  be  replaced  \\ith  gold  or  a  porcelain 
inlay  when  the  boy  is  grown  up.  In  distal 
cavities  where  the  labial  enamel  is  not  much 
encroached  on,  cement-lined  amalgam  can  be 
used  as  a  permanent  filling.  As  regards  the 
permanent  filling  to  be  used  in  incisors,  the 
choice  lies  between  cohesive  gold  with  or  without 
a  cement  lining,  a  cast-gold  inlay,  a  porcelain 
inlay,  or  a  silicate  cement.  Of  these  a  porcelain 
inlay  is  much  the  best  in  appearance,  and 
should  be  preferred  when  the  filling  is  a  con- 
spicuous one ;  should  the  filling  not  be  very 
12* 


visible,  a  gold  inlay  or  filling  should  be  inserted, 
as  having  perhaps  a  better  chance  of  perman- 
ence. In  a  gM's  mouth  one  is  justified  in  making 
great  sacrifices  for  the  sake  of  appearance,  and 
if  a  good  effect  can  be  best  attained  with  sUicate 
cement,  tliLs  material  should  be  used,  but  it 
must  be  remembered  tliat  such  fillings  will 
require  careful  and  frequent  inspection. 

Should  the  pulp  in  a  j'oung  patient  become 
exposed  and  have  to  be  removed,  it  is  not 
advisable  to  crown  the  tooth  as  long  as  its  shape 
and  appearance  can  be  preserved  by  means  of 
fillings  ;  this  remark  applies  even  more  strongly 
to  teeth  with  a  live  pulp. 

In  later  life  the  incisors  often  require  filling 
on  the  labial  surface  ;  the  best  filling  for  such 
cases  is  a  porcelain  inlay.  In  old  people  when 
the  labial  and  approximal  cavities  have  coal- 
esced, one  is  sometimes  obliged  to  use  amalgam 
or  even  gutta-percha  as  a  filling. 

Premolars  mid  Molars. — Coronal  cavities  are 
likely  to  appear  soon  after  eruption,  and  should 
be  at  once  filled  with  a  metal  filling  ;   in  the  first 
permanent  molar  this  wOl  generally  be  a  silver- 
tm  alloy,  as,  owing  to  the  youth  of  the  jjatient 
and  the  difficulty  of  securing  complete  dryness 
of  the  field  of  operation,  gold  will  be  contra- 
indicated.     If  it  can  be  done  without  distressing 
the  child  it  is  better  to  cut  out  all  the  fissures, 
as  by  so  doing  all  fear  of  recurrence  Ls  removed  ; 
but  this  cutting  out  is  not  essential,  as  such 
recurrence  can  be  dealt  with  later  if  it  occurs. 
Buccal  cavities  in  lower  molars  are  generally 
fissure   cavities   and   are   easily   controlled    by 
filling  with  amalgam.     In  upper  molars  they 
are  smooth  surface  cavities,  and  are  not  only 
very  difficult  to  excavate,  but  are  also  prone 
to  recur ;    for  this  reason  particular  attention 
should  be  given  to  brushing  the  buccal  surface 
of  the  first  permanent  upper  molar,  and  direc- 
tions to  this  effect  should  always  be  given.     If 
this    cavity    occurs    it    should    be    filled    with 
amalgam  ;   should  it  be  found  impossible  to  get 
sufficient  retention  for  this  material,  a  cement 
filling  may  be  used,  and  if  this  wears  out  it  can 
be  replaced  with  amalgam  when  the  child  is 
older  and  the  cavity  less  sensitive. 

Medial  cavities  in  the  first  permanent  molars 
should  be  carefully  watched  for  during  the  life 
of  the  second  deciduous  molars,  and  should  be 
filled  as  soon  as  they  are  detected  with  amalgam 
or  cement.  This  filling  must  be  regarded  as  a 
temporary  one,  and  when  the  second  deciduous 
molar  comes  out  (sometimes  it  should  even  be 
extracted  for  this  purpose)  this  filling  should  be 
extended  if  necessary  and  made  as  perfect  as 
possible ;  particular  attention  must  be  given 
to  the  contour  and  contact  point,  as  any  failure 
here  will  react  injuriously  on  the  alignment  of 
the  second  premolar  when  it  erupts.  If  the 
conditions  allow,  it  is  preferable  to  insert  a  gold 


362 


inlay  rather  than  an  amalgam  filling,  as  gold, 
besides  being  more  reliable  as  a  filling,  can 
be  made  to  give  a  better  contact  point  than 
amalgam. 

Should  one  unfortunately  have  to  fill  cavities 
in  the  molars  of  children  who  are  irregular  in 
their  attendance,  and  in  whom  the  cavities  are 
extensive,  the  difficulties  are  enormously  in- 
creased. In  these  cases  cement  should  be  used 
where  possible  as  a  lining  for  amalgam  filling 
in  large  cavities,  and  every  effort  should  be 
made  to  preserve  the  vitality  of  the  pulp,  as 
even  if  root-filling  becomes  ultimately  necessary, 
the  longer  it  is  postponed  the  more  likely  is  it 
to  be  successful  and  the  easier  to  carry  out. 
One  is  often  pleasantly  surprised  to  find  that 
immunity  comes  on  while  there  is  stiU  enough 
sound  dentine  left  in  the  tooth  to  form  a  base 
for  a  strong  fiUmg,  such  as  cement-lined  amal- 
gam or  a  gold  inlay,  and  that  devitalization  is 
not  necessary  after  all. 

The  same  principles  should  be  carried  out  in 
the  treatment  of  the  other  molars  and  of  the 
premolars.  In  the  case  of  the  latter  more  care 
should  be  taken  to  preserve  buccal  enamel,  and 
it  .should  be  supported  with  oxy-phosphate  of 
zmc  and  retamed  where  possible.  In  these 
teeth  also  porcelain  inlays  must  sometimes  be 
inserted  for  the  sake  of  appearance.  Should  it 
be  necessary  to  devitalize  an  upper  premolar, 
one  should  bear  in  mind  the  tendency  that  this 
tooth  has  to  split  when  there  has  been  much 
of  its  central  dentine  destroyed.  Something 
may  be  done  to  prevent  this  by  shaping  the 
fillmg,  but  it  is  best,  if  the  dentme  of  the  crown 
is  much  reduced,  to  crowir  the  root  at  once ;  if 
crowning  is  j)ostponed,  and  either  the  buccal  or 
Imgual  face  meantime  splits  off,  it  may  be  found 
impossible. 

This  rule  applies  also  to  devitalized  molars : 
whether  one  Ls  to  crown  the  tooth  or  fill  it  should 
depend  on  the  amount  of  sound  dentine  in  the 


tooth ;  if  there  is  not  sufficient  on  which  to 
build  a  strong  filling,  a  crown  should  be  applied. 
The  crowning  of  a  live  tooth  is  never  necessary. 

W.  G.  T.  S.' 


BIBLIOGRAPHY 


Dental 


(1)  Arnone,  L.     Case  of  Ludwig's  Angina. 

Cosmos,  1909,  Vol.  LI,  p.  1141. 

(2)  Arthur.    Dental    Cosmos,    1906,    Vol.    XLVIII, 

p.  35. 

(3)  Black,  G.  V.     Operative  Dentistry. 

(4)  Black,  G.  V.     Physical  Characters  of  the  Human 

Teeth.     Dental   Cosmos,    1895,  Vol.   XXXVII, 
p.  353. 

(5)  Black,  G.  V.    Dental  Cosmos,  1895,  Vol.  XXXVII, 

p.  965. 

(6)  Capon.     Dental  Cosmos,  1908,  Vol.  L,  p.  909. 

(7)  Clapp.     Kirk's    Amer.     Text-book    of     Operative 

Dentistry,  2nd  ed.,  p.  349. 

(8)  Friesell.     Dental  Cosmos,  1909,  Vol.  LI,  p.  1247. 

(9)  Gbayston,  Cass.     Brit.  Dent.  Jour.,  Vol.  XXXII, 

1911. 

10)  Guilford.     Kirk's  Amer.  Text-book  of   Operative 

Dentistry,  3rd  ed.,  p.  219. 

1 1 )  Johnson,  C.  N.     Principles  and  Practice  of  Filling 

Teeth. 

12)  Kirk.     Amer.   Text-book  of    Operative  Dentistry, 

3rd  ed.,  p.  219. 

13)  Makins.     Trans.  Odont.  Soc,  June,   1872. 

14)  Miller,  W.  D.     Micro-Organisms  of  the  Human 

Mouth,  p.  178. 

15)  Miller,   W.   D.     Lehrbuch    der    Konservierenden 

Zahnhcilkunde,  p.   117. 

16)  Parbott,    a.    H.     Anaesthesia    in    Conservative 

Work.     Brit.    Dent.   Jour.,    1909,    Vol.    XXX, 
p.   861. 

17)  Parrott,  a.  H.     Roy.  Soc.  of  Med. 

18)  Perry.     Dental  Cosmos,  1874,  Vol.  XVI. 

19)  PicKEKiLL,  H.  p.     Prevention   of   Dental   Caries 
and  Oral  Sepsis. 

)  RoTHMANN.     Patho-Histologie  der  Zahnpulpa,   p. 

188. 
)  RoTHMANN.     Zahnpulpa  und  Wurzelhaut,  p.  11. 
)  Sachs.     Scheff's  Handbuch  der  Zahnhcilkunde. 
)  Tomes,  C.  S.     Dental  Surgery,  5th  ed. 
)  Webb.     Dental  Cosmos,  1874,  Vol.  XVI,  p.  636. 
)  Webster,  A.  E.     Dental  Review,  1903,  p.  275. 
)  Williams,    Leon.      Dental    Cosmos,    1897,    Vol. 
XXXIX,  p.  289. 
(27)  WiTZEL,  A.     Das  F iillung  der  Ziihne  mil  Amalgam. 


(20) 

(21) 
(22) 
(23) 
(24) 
(25) 
(26) 


CHAPTER  XX 


ANTISEPTIC   TECHNIQUE   IN   DENTAL   SURGERY— DRESSINGS 

AND   TEMPORARY   FILLINGS 


ANTISEPTIC   TECHNIQUE 

Under  this  heading  it  is  intended  to  discuss 
briefly  the  application  of  the  principles  of 
asepsis,  antisepsis,  and  disinfection,  iii  the  prac- 
tice of  operative  dental  surgery.  There  are 
five  sources  of  infection  recognized  in  general 
surgery — 

(1)  the  field  of  operation,  or  patient, 

(2)  the  operator, 

(3)  the  instruments, 

(4)  the  material  used  (i.  e.  dressings,  etc.), 

(5)  aerial  particles ; 

and  the  utmost  care  is  taken  to  eliminate  in- 
fection from  each  of  these  sources.  There  can 
be  no  doubt  that  similar  precautions  should  be 
taken  in  the  practice  of  dental  surgery. 

Field  of  Operation 

Extraction  of  Teeth. — For  surgical  ^jrocedure, 
such  as  the  extraction  of  teeth,  it  is  not  possible 
to  secure  a  sterile  field,  but  much  may  be  done, 
and  should  be  done  in  duty  to  the  patient,  to 
render  the  oral  cavity  less  septic  in  certaiii  cases. 
For  instance,  when  the  extraction  of  teeth  has 
to  be  performed  in  an  unclean  mouth,  all  salivary 
calculus  should  first  be  removed,  the  teeth 
scrubbed  with  a  stiff  tooth-brush  and  a  detergent 
tooth-powder,  and  a  strong  antiseptic  mouth- 
wash used  vigorously  for  some  time  immediately 
before  the  operation.  Tooth-brushes  with 
metal  handles  are  now  made,  and  these  can  be 
sterilized  very  well  by  boiling,  so  that  a  few 
(at  least  in  hospital  practice)  serve  for  many 
patients.  The  only  drug  of  any  real  value  as 
a  mouth-wash  is  perchloride  of  mercury,  used 
in  a  strength  of  1  in  2500.  Tliis  may  be  used 
in  simple  aqueous  solution,  or  combined  with 
ammonium  chloride  in  equal  strength  to  render 
it  less  distasteful  to  the  patient ;  or  a  more 
pleasant  mouth-wash  may  be  made  by  combin- 
ing with  it  such  drugs  as  menthol,  eucalyptus, 
glycerme,  and  gaultheria.  In  a  series  of  some 
270  tests  Hunt  (1)  found  that  this  was  the  only 
mouth-wash  of  which  tests  made  an  hour 
after  use  showed  any  decrease  in  the  num- 
ber of  organisms  in  the  mouth,  and  this  is 
confirmed  by  the  writer's  experience,  clinical 
and  experimental. 


The  oral  tissues  have  such  wonderful  powers 
of  resistance  and  recuperation  that  given  this 
advantage  they  will  make  a  good  recovery.  It 
is  necessary,  however,  to  take  these  precautions 
to  prevent  septic  matter  being  carried  down 
deep  into  the  tissues  by  the  blades  of  the  forceps, 
and  thus  giving  rise  to  those  cases  of  intense 
swelling,  mflammation,  sloughing,  or  necrosis, 
which  otherwise  not  infrequently  supervene. 

Hypodermic  Injections. — The  surface  of  the 
mucous  membrane  should  be  sterilized  as  far 
as  possible  before  being  punctured  by  the 
needle,  in  order  to  prevent  infection  from  the 
surface  being  forced  deeply  into  the  tissues. 
Tincture  of  iodine  rubbed  on  the  surface  with 

I  a  pledget  of  cotton-wool  serves  well  for  this 
purpose,   and  probably   has  the  advantage   of 

I  counteracting  the  deleterious  prolonged  eSect 
of  adrenalin  chloride,  by  causing  a  local  vaso- 
dilatation and  leucocytosis,  which  render  the 
wounded  tissue  less  liable  to  invasion  by 
micro-organisms. 

Sterility  of  the  Field  in  Conservative  Operations 

Caries  of  the  teeth  is  admittedly  caused  by 
bacterial  infection,  and  there  can  be  no  question 
as  to  the  absolute  necessity  of  removing  all 
infection  before  proceeding  to  replace  the  lost 
tissue.  Again,  there  can  be  no  doubt  that 
mechanical  means  alone  are  as  a  rule  insufficient 
to  sterilize  the  dentme,  ^vith  the  consequence 
that  there  is  always  the  possibility,  if  nothing 
further  be  done,  of  a  recurrence  and  extension 
of  caries  beneath  the  filling  or  crown.  In  some 
cases  too  it  may  be  desirable  not  to  carry 
excavation  to  the  extreme  limit,  in  order  to 
avoid  an  exposure  of  the  pulp  ;  or  in  other  cases 
it  may  be  desired  to  retam  certain  tissue,  the 
sterility  of  which  is  doubtful,  for  mechanical 
support.  In  all  cases,  therefore,  it  becomes 
necessary  to  have  recourse  to  disinfection  by 
drugs. 

The  choice  of  drugs  will  depend  upon  the 
particular  surface  to  be  sterilized. 

(a)  For  the  sterilization  of  dentine  in  root- 
canals,  which  is  usually  infected,  or  may  be 
slightly  softened,  a  dressing  of  formalin,  10  % 
or  even  pure,  is  undoubtedly  best,  on  account 
of  its  great  penetrating  po\\er.  Simms  (7)  has 
,  shown  that  in  strong  solutions  it  penetrates 
363 


Oxy-phosphate  of  zinc. 


Oxy-phosphate  of  Copper. 


Copper  Amalgam. 


"  True-dent  Alloy  "   Amalgam 


Fellowship  Amalgam. 


Gold  Annealed. 


reddobd  one-halp. 
Fig.  440. 


The  cements  were  mixed  on  ordinarily  clean  slab,  with  spatula,  and  placed  in  Petri  dish. 

The  amalgams  were  mixed  in  ordinarily  clean  (unsterilized)  mortar,  and  also  in  hand  previously 
washed  with  carbolic  soap.  The  agar  was  inoculated  from  a  broth  culture  from  cariotis  dentine 
and  placed  in  the  incubator  (at  body  temperature,  37°  C.)  for  two  days. 

The  shaded  portion  in  Petri  dish  represents  colonies  of  organisms.      (British  Denial  Journal.) 


Oxy-phosphate  of  Zinc. 


Oxy-phosphate  of  Copper. 


Copper  Amalgam. 


Fellowship  Amalgam. 


■  True-dent  Alloy  "  Amalgam. 


Gold  unaiinealed. 


REDUCED  ONE-HALF. 


Fig.  441. 


The  cements  and  amalgams  were  mixed  and  allowed  to  set  for  one  day,  sterilized  by  boiling 
for  five  minutes,  and  placed  in  sterile  Petri  dish  and  allowed  to  become  quite  cold. 

Agar  shake  cultures  were  inoculated  with  two  loopfuls  of  two-day  broth  culture  from  carious 
tooth,  and  incubated  at  37°  C  for  two  days. 

The  shaded  portion  in  Petri  dish  represents  colonies  of  organisms.     {British  Dental  Journal.) 


366 


the  whole  thickness  of  the  dentine  of  the  root, 
and  tlie  WTiter  (5)  tliat  a  10  %  solution  easily 
penetrates  1-5  mm.  of  dentine,  and  prevents 
bacterial  growth  in  agar  for  3  mm.  beyond. 
Formalin  may  be  combined  with  creosote  and 
glycerine,  or  tricresol ;  or  the  polymer,  paraform, 
may  be  used  in  a  similar  manner. 

{b)  For  the  sterilization  of  the  surfaces  of 
teeth  to  be  covered  by  a  crown  no  better  drug 
can  be  used  than  silver  nitrate  m  a  solution  of 
20  grains  to  the  ounce.  This  has  the  double 
advantage  of  acting  as  a  powerful  disinfectant 
and  of  forming  an  albuminate  of  silver,  which 
is  insoluble  in  acids  and  so  protects  the  surface 
mechanically ;  the  latter  fact  was  demonstrated 
by  Miller  (3)  in  an  interestmg  experiment.  The 
surface  so  treated  must  be  carefully  neutralized 
with  a  solution  of  sodium  chloride  before  appli- 
cation of  the  phosphate  cement ;  otlierwise  any 
free  silver  nitrate  will  react  with  the  phosphoric 
acid  and  form  nitric  acid.  This  will  not  affect 
the  tooth,  but  will  disintegrate  the  cement. 

(c)  The  sterilization  of  "  cavities  ".  It  is  of 
course  a  sine  qna  non  that  the  cavity  must  be 
kept  dry  during  and  after  excavation  of  infected 
tissue.  The  student  should  always  think  of 
dentine  as  a  porous  substance,  the  porosities 
of  which  are  filled  up  either  by  w'ounded,  living, 
and  sentient  tissue,  or  by  similar  tissue  in  a 
necrosed  condition  ;  in  either  case  it  is  obviously 
in  a  most  favourable  state  for  infection  by 
micro-organisms,  with  which  the  saliva  is 
loaded.  But,  further,  it  is  not  possible  to  know 
that  a  cavity  is  sterile,  even  if  it  has  been  kept 
dry  and  excavation  appears  to  be  complete — 
tlie  probability  is  that  it  is  not.  The  dentine 
should,  therefore,  be  carefully  sterilized  before  the 
filling  is  inserted ;  neglect  of  this  precaution  (in 
the  writer's  opinion  at  least)  is  the  cause  of  many 
of  those  cases  of  extension  of  caries  and  inflam- 
mation of  pulp  (the  latter  especially,  owing  to 
infection  along  the  tubules  without  softening) 
that  occur  under  fillings  inserted  by  otherwise 
most  careful  operators. 

In  order  to  sterUize  the  cavity,  the  dentine 
should  firstly  be  thoroughly  dehydrated  with 
alcohol  and  warm  air,  and  then  treated  for  as 
long  a  time  as  possible  with  a  strong  disinfectant. 
The  relative  penetrating  and  germicidal  powers 
of  the  chief  disinfectants  have  been  estimated 
by  the  writer  {loc.  cit.).  Perchloride  of  mercury 
was  found  to  be  the  most  efficient ;  in  a  strength 
of  1  in  1000  it  readily  penetrated  and  disinfected 
1"5  mm.  of  dentine  and  8  mm.  of  agar  beyond. 
"  Pure  "  carbolic  acid  was  also  found  to  be 
quite  efficient  for  dentine  of  the  same  thickness 
(in  using  carbolic  acid  sufficient  water  should 
be  added  to  make  it  quite  liquid ;  in  this  con- 
dition it  is  a  much  stronger  antiseptic  than  when 
quite  pure).  Formalin  is  not  of  much  value 
for  this  work  unless  it  can  be  sealed  in,  since  the 


formic  aldehyde  gas  escapes  into  the  mouth  and 
will  not  penetrate  the  dentine.  The  essential 
oils  were  shown  to  be  very  poor  penetrators. 
Should  there  be  only  a  thin  layer  of  dentine 
covering  the  pulp,  the  carbolic  may  be  advan- 
tageously combined  with  thymol ;  this  destroys 
the  escharotic  properties  of  the  carbolic.  If  it 
is  particularly  desired  to  retain  any  dentine 
that  is  obviously  infected,  one  of  the  above 
drugs  should  be  sealed  in  the  cavity  for  at  least 
24  hours ;  formalin  in  10  per  cent  solution  is 
useful  in  these  cases,  but  is  liable  to  cause 
irritation  if  the  pulp  is  alive. 

Sterility  of  Material 

(o)  For  Root-fillmgs. — It  is  quite  obvious  that 
any  material  used  for  this  purpose  should  be 
absolutely  sterile,  either  by  being  of  itself 
antiseptic  (e.  g.  oxy -chloride  of  zinc,  combina- 
tions of  paraform  and  zinc  oxide,  etc.),  or  by 
having  been  sterilized.  That  so  large  a  number 
of  substances  have  been  at  various  times  advo- 
cated for  root-filling,  is  undoubtedly  due  to  the 
fact  that  the  one  essential — that  of  sterility — 
was  not  recognized.  No  material  that  is  not 
antiseptic,  or  cannot  be  sterilized  by  the 
operator,  should  be  used  for  root-filling.  Gutta- 
percha points,  especially,  should  be  sterilized 
before  use ;  this  obviously  cannot  be  effected 
by  boiling,  but  may  be  quite  conveniently  done 
by  keeping  a  stock  of  them  in  a  solution  of 
ji  -  naphthol  and  alcohol  in  a  wide-necked 
stoppered  bottle,  and  only  withdrawing  one 
immediately  before  use,  care  being  taken  to 
avoid  contamination  on  the  bracket  or  m  the 
mouth. 

(h)  For  Fillings. — IVCUer's  (4)  experiments 
showed  that  some  filling  materials,  such  as  cop- 
per amalgam  or  oxy-cldoride  of  zinc,  possessed 
definite  antiseptic  properties.  This  has  been 
confirmed  by  the  writer  (loc.  cit.)  with  the 
exception  of  unannealed  gold,  which  was  not 
found  to  be  antiseptic  (See  Figs.  440,  441). 
Such  filling  materials,  therefore,  it  is  not 
necessary  to  sterilize,  and  gold  is  usually 
quite  efficiently  sterilized  by  annealing.  Oxy- 
phosphate  of  zinc  was  also  shown  to  be  mildly 
antiseptic. 

With  regard  to  silver -tin  amalgams,  it  was 
also  shown  by  the  author  that  not  only  were 
they  not  disinfectant,  but  that  if  mixed  in  the 
usual  way  were  capable  of  carrying  infection 
into  a  cavity;  but,  further,  that  this  can  be 
overcome  by  mixing  the  amalgam  with  alcohol 
or  methylated  spirit  and  allowing  evaporation. 
In  this  coimection  it  has  been  proposed  to  take 
advantage  of  the  marked  antiseptic  value  of 
copper  amalgam  by  lining  cavities  with  this 
material  and  completmg  with  ordinary  amalgam ; 
the  staming  properties  of  copper  amalgam, 
though,  have  to  be  remembered. 


367 


Oxy -chloride  of  ziiic  may  be  used  in  a 
similar  mamier,  but  here  the  irritating  properties 
of  the  material  must  be  borne  in  mind,  when 
it  is  placed  in  deep  cavities.  No  material  that  is 
not  aseptic,  or  cannot  be  sterilized,  should  be  used 
for  filling  teeth. 

Sterility  of  Instruments  (see  Chapter  XVII) 

All  instruments  that  will  stand  it  sliould  be 
boUed  for  five  minutes  after  each  operation. 
Instruments  that  are  used  on  the  soft  tissues, 
such  as  forceps,  lancets,  knives,  etc.,  are  best 
boOed  before  and  after  use,  in  order  to  destroy 
spores  eflfectually  and  to  disinfect  any  "dust  " 
that  might  have  accunuilated  on  them  since 
the  last  time  of  using.  Burrs  should  be  first 
cleaned  and  then  boiled.  The  addition  of 
carbonate  of  soda  to  the  water  (a  teaspoonful  to 
the  pint)  prevents  the  instruments  from  rustmg. 
Boiling  is  said  to  dull  the  fine  edge  of  cutting 
instruments,  but  this  is  more  probably  due  to 
careless  handling  in  the  sterilizer ;  in  any  case 
such  instruments  requu'e  frequent  sharpening, 
and  the  objection  should  not  be  allowed  to 
stand  in  the  way  of  efficient  sterilization. 
Instruments  may  be  sterilized  by  prolonged  im- 
mersion in  disinfectants — the  mere  dipping  of 
an  instrument  in  an  antiseptic  for  a  minute  or 
so  does  very  little  or  no  good,  and,  in  the  words 
of  Lockwood  (2),  is  "  mere  fetish  ".  All  instru- 
ments should  be  made  of  polished  metal 
throughout ;  wooden  "  ebony  "  handles  cannot 
be  boiled  or  soaked  in  disinfectants,  without 
being  spoUed,  and  therefore  should  be  dis- 
carded. It  is  highly  important  that  all  root- 
canal  instruments  should  be  sterUe.  This  may 
be  effected  by  keeping  them  in  a  disinfectant 
solution,  such  as  ^-naphthol  and  alcohol.  A 
convenient  method  of  doing  this  is  to  insert 
the  blunt  ends  of  the  bristles,  cleaners,  and 
broaches,  into  the  under-side  of  the  cork  of  a 
wide-necked  bottle,  which  is  kept  fUled  with 
the  disinfectant  solution.  If  such  instruments 
have  been  used  for  septic  canals,  they  should 
be  boiled  before  being  replaced  in  the  bottle. 
A  stock  of  bristles,  etc.,  should  be  kept  in  this 
manner,  and  no  single  one  used  twice  in  the 
same  day. 

Hypodermic  Syringes. — These  have  undoubt- 
edly been  a  fruitful  source  of  infection  in  recent 
years.  Unfortunately  many  othemise  very 
suitable  forms  of  sjTinge  contain  a  leather 
washer  at  the  upper  end  of  the  cylinder,  and 
the  whole  of  tlie  instrument  camiot  therefore 
be  boiled.  The  needle,  however,  should  be 
boiled  after  use ;  and  the  syringe  should  be 
filled  with  a  weak  solution  of  lysol,  and  placed 
upright  in  a  "  Bardett  "  sterilizer,  or  small 
bottle  (with  a  wide  base),  containing  a  similar 
solution,  and  so  kept  until  next  required. 

"  All  metal  "  and  "  all  glass  "  syringes  have 


the  advantage  that  they  can  be  sterilized  by 
boiling;  but  the  former  rapidly  wear  out,  and 
the  latter  are  too  weak. 

The   Operator   (see  Chapter  XVII) 

Although  it  may  not  be  necessary  for  dental 
surgeons  to  pay  the  same  care  and  attention  to 
the  sterilization  of  the  hands  asageneral  surgeon, 
yet  the  matter  is  to  be  by  no  means  neglected. 
Infection  may  be  only  too  readily  carried  from 
one  patient  to  another.  One  patient  with  a 
high  tissue  resistance  may  contaiia  in  his  mouth 
such  organisms  as  tubercle  bacilli,  diphtheria 
bacilli,  or  pneumococci,  and  yet  be  in  good 
health ;  but  these  same  organisms  may  produce 
an  attack  of  a  most  serious  disease  if  introduced 
into  the  mouth  of  a  patient  having  a  low  tissue 
resistance  or  a  "  low  opsonic  index  "  to  one  of 
them.  The  treponema  pallida  and  the  contagia 
of  exanthemata  may  also  be  transferred,  not 
only  from  patient  to  patient,  but  also  from 
patient  to  operator.  It  has  been  shown,  too. 
by  the  writer  (6)  that  organisms  may  be  trans- 
ferred from  the  hands  to  filling-material,  such 
as  amalgam,  and  so  infect  an  otherwise  sterile 
cavity. 

Before  and  after  each  patient,  therefore,  the 
hands  should  be  scrubbed  with  a  clean  nail- 
brush, soap,  and  hot  water;  and  before  perform- 
ing extractions  at  all  extensive  the  hands  should 
also  be  washed  in  either  a  solution  of  biniodide 
of  mercury,  1  in  500,  or  a  solution  of  lysol,  1  in 
40,  for  three  minutes. 

Atmospheric  Infection  (see  Chapter  XVII) 
It  is  neither  practicable  nor  necessary  in 
dental  surgery  to  take  such  minute  precautions 
against  infection  from  this  source  as  are  taken 
in  general  surgery.  Yet  gross  infection  from 
dust-laden  air  shoiildbe  avoided.  Theroomwhere 
dentaloperations  are  performed, should, of  course, 
be  ventilated,  but  should  not,  if  possible,  derive 
its  air  supply  from  a  busy  and  dusty  thorough- 
fare ;  with  the  constant  increase  of  motor  traffic 
this  precaution  becomes  daily  more  important. 
The  appointments  of  the  room,  whilst  not 
savouring  too  much  of  the  operatmg  theatre, 
should  not  be  such  as  unnecessarily  to  accumu- 
late dust,  which  may  be  given  off  again  at  some 
inopportune  time.  Instruments  and  materials 
should  be  protected  from  dust  infection  as  much 
as  possible.  Every  kind  of  material  should  be 
kept  in  well-stoppered  bottles.  Instruments 
should  preferably  be  kept  on  glass  shelves ;  the 
glass  is  readily  cleansed  ^^■ith  antiseptic  solutions, 
and  moreover  the  slightest  trace  of  dust  is  at 
once  visible.  Cabinets  lined  with  leather  or 
baize  are  to  be  regarded  as  relics  of  the  pre- 
Listerian  age. 

Because  it  has  been,  or  is,  possible  to  attain 
a  measure  of  "  success  "  without  the  observance 


368 


of  such  principles  of  asepsis,  is  it  necessary  that 
they  should  be  carried  out  in  such  detail  ? 
There  can  be  no  doubt  as  to  the  answer.  The 
principle  involved  is  unquestionably  a  right 
one ;  therefore  its  conscientious  application 
should  follow  as  a  matter  of  course.  If  the 
work  of  the  dentist  can  thereby  be  made  only 
one-tenth  more  efficacious,  or  unnecessary  infec- 
tion eliminated,  and  if  his  patients  can  thus  be 
saved  only  one-tenth  of  their  pain,  suffering,  or 
discomfort,  then  it  is  clearly  his  duty  to  practise 
aseptic  dental  surgery. 

DRESSINGS 

No  dressing  sliould  be  inserted  in  a  cavity 
or  applied  to  a  tooth  unless  it  is  intended  to 
accomplish  some  definite  object.  The  condition 
of  the  tooth,  therefore,  should  first  be  clearly 
understood ;  and  then  a  dnig  or  material 
selected  that  both  can  and  will  accomijlish  the 
desired  object. 

Dressings  may  be  classified  as  follows — 

1.  Emergency  dressings. 

(a)  For  the  relief  of  pain. 
{b)  Pre-Operation. 

2.  Dressings  to  devitalize  the  pulp. 

3.  Dressings  to  obtund  dentine. 

4.  Dressings  for  mechanical  effect. 

(a)  Separation  of  teeth. 
{b)  Preservation  of  enamel  edges, 
(c)  For    expression     of    "polypi"    or 
hypertrophied  gum. 

5.  Antiseptic  dressings. 

1.  Emergency  Dressings 
(a)  For  the  Relief  of  Pain. — Pain  may  be  due 
to  inflammation  of  the  pulp  or  periodontal 
membrane.  If  the  former,  the  chief  con- 
siderations are  to  protect  the  surface  of  the 
pulp,  and  to  apply  a  sedative  and  antiseptic 
drug.  For  this  purpose  nothing  is  so  generally 
useful  as  the  well-known  "  carbolized  resin  and 
zinc  oxide  "  dressmg,  for  which  the  following 
is  a  useful  formula — 

R    Acidi    Carbolici    .        .        .      ^ij. 
Resinae  .        .        .        .      5ij- 

Spiritus  Mni  Rectificati    .      "^iv. 
M. 

To  be  mixed  with  zinc  oxide  and  cotton-wool 
to  the  consistency  of  a  stiff  paste. 

The  cavity  should  be  syringed  out  with  warm 
water,  excavated  if  possible,  and  dried  ;  the  plug 
of  carbolized  resin  is  then  inserted.  The  watery 
saliva  precipitates  the  resin  from  solution  and 
the  spirit  evaporates ;  in  this  way  it  "  sets  ",  and 
a  firm  protective  and  sedative  dressing  is  the 
result.  Another  well-known  preparation  for 
this  purpose  is  a  mixture  of  equal  parts  of 
carbolic  acid,  thymol,  and  menthol;  this  is  far 
superior  in  its  antiseptic  properties  to  carbolized 


resin,  but  it  requires  to  be  sealed  in  the  cavity 
mth  cement  or  gutta-percha,  all  pressure  being 
avoided. 

Other  drugs  that  may  be  used  in  a  similar 
maimer  are  oil  of  cloves,  eugenol,  creosote, 
chloretone,  and  cocaine.  Useful  combinations 
of  these  are  as  foUows — 

(1)  Zinc    oxide    and    oil    of    cloves    mixed 

fresh  and  to  "saturation".     This  mix- 
ture sets  hard  in  a  few  hours. 

(2)  Cocainae  Hydrochloridiim        .  gr.  x. 
Chloretone           ....  gr.  xx. 
Acidum  Carbolicum  .        .        .  3i- 
Oleum  Caryophylli    .        .        .  Jij. 

To  be  soaked  on  cotton-wool  and  sealed  in  the 
cavity. 

Pure  carbolic  acid  should  7iever  be  used  alone 
for  this  purpose,  since  it  forms  a  dense  coagulum 
on  the  surface  of  the  pulp,  through  which  it  is 
difficult  or  impossible  for  drugs  like  arsenic  or 
cocaine  to  penetrate,  should  this  be  desired,  on 
a  subsequent  occasion. 

Pain  due  to  Periodontitis. — Simply  to  effect 
relief  in  this  condition  it  is  best  to  open  up  the 
cavity  as  freely  as  possible,  and  to  leave  it  open. 
Counter-irritants,  hot  fomentations,  or  small 
bread  poultices  inside  the  mouth,  or  scarifica- 
tion of  the  gums,  may  severally  be  used  with 
advantage  according  to  the  stage  of  periodontitis 
present.  If  the  periodontitis  is  not  severe,  it 
may  be  relieved  (and  cured)  by  a  dressing  of 
formalin  and  tricresol  sealed  in  the  pulp-chamber 
and  canals ;  the  rationale  of  the  method  being 
that  the  liberated  formic  aldehyde  gas  at  once 
destroys  the  organisms  that  caused  the  condi- 
tion, and  the  tricresol  chemically  unites  with 
the  irritating  products  of  decomposition  of  the 
pulp  and  neutralizes  them. 

(b)  Dressings  Preparatory  to  Major  Operations. 
It  is  fortunately  becoming  more  and  more 
customary  for  surgeons  before  operating  on  the 
mouth,  throat,  or  abdomen,  to  require  the 
patient's  mouth  and  teeth  to  be  rendered  as 
aseptic  as  possible.  This  is  undoubtedly  a  very 
wise  precaution,  since  it  eliminates  a  most 
frequent  and  potent  source  of  infection,  and 
thus  minimizes  the  risk  of  suppuration  of 
wounds,  tearing  of  sutures,  parotitis,  or  more 
serious  complications  such  as  septic  pneumonia. 
The  dental  surgeon  is  often  called  upon  for  such 
services  at  short  notice,  and  it  becomes  his  duty 
to  render  the  teeth  and  gums  as  healthy  as 
possible  in  a  comparatively  short  space  of  time. 
But  because  this  has  to  be  done  it  does  not 
follow  that  the  general  principles  of  conservative 
dentistry  are  to  be  abandoned,  and  the  patient's 
teeth  ruthlessly  or  unnecessarily  sacrificed ;  on 
the  other  hand  permanent  fillings,  etc.,  are  out 
of  the  question. 


3C9 


The  method  adopted  by  the  wTiter  under 
such  ckcumstances  is  as  follows — Whenever  it 
can  possibly  be  arranged  the  patient  is  placed 
under  a  major  anaesthetic ;  there  is  as  a  rule  no 
difficidty  about  this  in  hospital  ^^•ork,  and  it 
shovdd  be  insisted  on  as  far  as  possible  in  jirivate. 
When,  however,  for  various  reasons  this  method 
cannot  be  pursued,  recourse  is  had  to  local 
anaesthesia  by  the  "  bone  injection  "  method. 
It  is  essential  for  rapid  work  that  the  field  of 
operation  should  be  insensible.  The  work  is 
then  proceeded  with  in  the  following  order. 
Thefcarious  tissue  from  all  cavities  is  removed 
rapidly  with  chisel,  excavator,  and  burr;  if  the 
pulp  is  not  involved,  a  dressing  of  pure  carbolic 
acid,  and  a  large  pledget  of  cotton-wool  are 
inserted  temporarily.  If  the  pulp  is  involved 
it  is  immediately  extirpated,  and  if  possible  the 
canals  filled  with  sterile  gutta-percha  points ;  or 
the  body  of  the  pulp  may  be  removed,  the  fine 
root-canals  being  left.  In  cases  where  the  pulp 
is  gangrenous  and  there  are  no  marked  signs  of 
periodontitis,  the  canals  are  cleaned  out,  and 
dressings  of  formalin  and  tricresol  inserted,  and 
immediately  sealed  in  with  gutta-percha  or 
cement.  When  either  marked  periodontitis  or 
alveolar  abscess  (acute  or  clironic)  exists,  the 
tooth  is  avoided  for  the  present.  An  assistant 
now  mixes  a  large  quantity  of  oxy-phosphate 
cement,  and  as  many  of  the  cavities  as  possible 
are  filled,  and  rapidly  coated  with  mastic  var- 
nish. In  those  cases  in  ^^•hich  the  pulp  was 
amputated  only,  a  mixture  of  carbolized  resm 
and  zinc  oxide  on  sterile  cotton-wool  is  placed 
in  the  cavity  underneath  the  oxy-phosphate. 

Attention  is  next  paid  to  deposits  of  salivary 
calculus,  and  to  the  treatment  of  any  "  pyorrhoea 
alveolaris  ''  that  may  be  present.  The  gums  and 
teeth  are  first  swabbed  witli  peroxide  of  hydrogen 
for  several  minutes,  and  tliis  is  removed  with 
tincture  of  iodine.  The  calculus  is  removed  as 
thorouglily  as  circumstances  ^^ill  jiermit  with 
Howe  and  Good  Younger  instruments.  Through- 
out, an  assistant  makes  constant  applications 
of  tincture  of  iodine,  and  it  is  found  that  this 
controls  any  bleeding  and  acts  as  a  very  eiBcient 
antiseptic.  All  pyorrhoea  pockets  are  next 
freely  excised,  in  order  to  eliminate  any  focus  of 
infection  (also  as  one  of  the  best  remedial 
treatments    for    the    condition),  and    dressings 


of  peroxide  of  hydrogen  and  iodine  are  again 
applied.  This  usually  arrests  the  haemorrhage 
and  enables  the  finer  deposits  of  calculus  to  be 
removed  more  readily,  since  they  are  perfectly 
visible.  The  teeth  are  then  brushed  with  a  stiff 
rotary  brush  on  the  engine,  with  j'umice  and 
water.  Finally,  any  septic  or  hopelessly  loose 
teeth  are  extracted. 

Most  mouths  can  be  treated  in  this  manner 
in  a  remarkably  short  time — -half  an  hour  to 
three-quarters  of  an  hour,  if  the  patient  is 
anaesthetized,  is  usually  sufficient.  One  hour, 
or  two  sittings,  may  be  necessary  if  local 
anaesthesia  has  to  be  employed.  Those  who 
have  not  performed  conservative  dental  opera- 
tions under  general  anaesthesia  can  with  diffi- 
culty realize  the  ease,  freedom,  and  rapidity 
with  which  such  work  can  be  carried  out  with 
the  aid  of  some  trained  assistance. 

Numbers  2,  3  and  4,  will  not  be  discussed 
here  as  they  are  fully  and  more  appropriately 
described  in  other  sections  of  this  work. 

5.  Antiseptic  Dressings 

These  have  already  been  discussed  in  the 
previous  part  of  this  section;  it  remains  only 
to  add  that  advantage  should  be  taken  of  a 
penetrating  antiseptic  dressing  wherever  and 
whenever  possible.  Wlien  a  temporary  filling 
is  inserted  merely  to  preserve  things  in  statu 
quo  until  the  next  visit,  it  should  be  either 
decidedly  antiseptic  itself  or  should  be  placed 
on  the  top  of  an  antiseptic  dressing ;  so  that  the 
dentine  may  be  gradually  sterilized  in  the 
interval,  and  thus  the  length  of  the  next  sitting 
perhaps  lessened,  and  the  sterility  of  the  cavity 
assuredlv  rendered  more  certain. 

H.P.P. 

BIBLIOGRAPHY 

(1)  Hunt.     Dental  Cosmos,  1904,  Vol.  XLVI,  p.  825. 

(2)  LocKWOOD.     Antiseptic  Surgery,  p.  178. 

(3)  Miller.     Dental  Cosmos,  1905,  Vol.  XLVII,  p.  917. 

(4)  Miller.     Micro-Organisms  of  the  Human  Mouth. 

(5)  PiCKERiLL,  H.  P.     Brit.   Dent.   Jour.,    1909,   Vol. 

XXX,  p.  1185. 

(6)  PiCKERiLL,    H.    P.     Brit.   Dent.  Jour.,    1909,   Vol. 

XXX,  p.  1191. 

(7)  SIMMS.    Proc.  Roy.  Soc.  of  Med.  (Odont.  Sec),  1909, 

p.  99. 


CHAPTER  XXI 


THE   MANIPULATION   OF   GOLD 


The  preparation  and  properties  of  gold  are 
fully  described  in  text-books  of  Metallurgy, 
and  it  will  be  sufficient  for  present  purposes  to 
mention  that  gold  is  a  very  soft  metal,  its 
specific  gravity  is  19"3,  it  is  a  good  conductor 
of  heat  and  electricity,  and  that  it  has  the 
remarkable  property  in  certam  circumstances  1 
of  welding  at  ordinary  temperatures. 

As  prepared  for  use  in  filling  teeth,  gold 
comes  to  hand  in  two  varieties,  cohesive  and 
non-cohesive,  and  a  very  simple  experiment 
will  demonstrate  the  difference  between  them. 
If  two  well-annealed  strips  of  cohesive  foil  are 
allowed  to  come  m  contact  with  one  another, 
they  will  cohere  firmly  at  the  points  of  con- 
tact, and  if  the  two  surfaces  are  brought  into 
apposition  with  slight  pressure,  they  will  weld 
together  so  firmly  that  they  will  tear  across 
rather  than  come  apart.  Hence  a  cohesive 
filling  is  a  solid  piece  of  metal,  and  can  be  built 
out  to  form  a  corner  or  edge  with  little  risk  of 
subsequent  disintegration.  A  non-cohesive  fill- 
ing, on  the  other  hand,  is  composed  of  a  number 
of  separate  pieces,  not  sticking  to  one  another, 
but  packed  together  as  so  much  paper  might 
be,  and  it  can  be  easily  picked  to  pieces  if 
removed  from  its  contaming  cavity. 

The  terms  "  hard  "  and  "  soft  "  are  sometimes 
used  instead  of  "cohesive  "  and  "non-cohesive  ", 
on  account  of  the  different  behaviour  of  the 
two  kinds  during  manipulation  (if  properly 
made,  both  fillings  are  equally  hard).  If  a 
number  of  cylmders  of  non-cohesive  gold  are 
placed  in  a  cavity  and  steadily  compressed 
against  one  side,  they  wOl  yield  before  the 
instrument,  by  glidmg  of  the  layers  over  one 
another,  until  all  the  air  spaces  have  been 
obliterated.  If  annealed  cohesive  cylinders 
are  treated  in  the  same  way,  their  surface 
layers  wiU  cohere  together  and  form  a  hard 
cake,  which  resists  the  instrument  and  prevents 
the  underlying  parts  from  being  condensed, 
the  hard  feeling  in  this  case  being  very  different 
from  the  soft  yielding  feel  of  the  non-cohesive 
gold.  In  just  the  same  way  a  bag  of  shot  feels 
softer  than  a  bag  of  clay. 

Cohesive  Gold. — There  are  two  kinds  of  co- 
hesive gold,  sheet  and  mat,  the  latter  of  which 
is  a  loosely  coherent  spongy  mass  of  minute 
crystals. 

Sheet,  or  foil,  is  made  from  the  cast  ingot  by 

3 


roUmg  and  hammering.  The  various  thick- 
nesses are  distinguished  by  number,  the  number 
in  each  case  corresponding  to  the  weight,  in 
grains,  of  a  sheet  four  inches  square  ;  thus  16  sq. 
ins.  of  No.  4  wiU  weigh  4  grs.,  from  which  it 
win  appear  that  this  particular  sheet  is  about 
^owo  of  an  mcli  thick.  No.  32  wiU  be  eight 
times  as  thick  as  No.  4,  and  it  wiU  be  called 
"  32  ",  whether  it  is  a  single  sheet  of  an  approxi- 
mate thickness  of  Tr5\j„  of  an  inch,  or  composed 
of  several  thmner  layers,  provided  that  a 
square  inch  of  the  combination  weighs  2  grs. 
The  different  thicknesses  have  different  uses; 
the  thmner  kinds  can  be  more  easily  adapted 
to  the  margins  and  wall  of  cavities,  especially 
where  pits  or  grooves  are  to  be  filled ;  thick 
sheet,  on  the  other  hand,  tends  to  make  a 
much  more  solid  fiUing,  partly  because  there 
are  actually  fewer  layers  to  the  same  quantity 
of  material,  and  partly  because  its  stiffer 
character  necessitates  a  more  careful  lamina- 
tion, and  hence  a  more  complete  obliteration 
of  air  spaces.  If  thin  foil  is  used,  it  should 
be  thin  enough  to  allow  of  its  beuig  crumpled 
and  condensed  as  a  pellet,  independently  of  the 
lamination  of  its  layers ;  No.  4  is  the  one  most 
generally  used ;  if  much  thicker  than  this,  the 
gold  can  only  be  properly  condensed  ia  parallel 
layers. 

It  would  take  an  extremely  long  time  to 
build  up  a  whole  fillmg  with  single  layers  of 
No.  4,  so  some  more  expeditious  method  must  be 
used.     Of  these  there  are  three  in  common  use— 

(1)  The  sheet  of  No.  4  may  be  folded  double, 
then  double  agam,  and  then  a  third  time ;  this 
procedure  will  reduce  its  size  to  two  square 
inches  and  mcrease  its  thickness  to  32.  So 
treated,  its  workmg  properties  will  be  somewhat 
intermediate  between  those  of  thick  foil  and 
thin ;  it  will  allow  itself  to  be  satisfactorily  con- 
densed ui  pits  and  grooves,  and  if  carefully 
lammated,  will  make  a  filling  that  will  compare 
favourably  with  one  made  of  thick  or  "  heavy  " 
foU. 

(2)  Tlie  sheet  may  be  cut  mto  strips  of  J  or 
^  inch  width,  and  the  strips  made  into  ropes 
by  lightly  roUing  them  between  two  layers  of 
clean  dry  wash-leather.  Tlie  ropes  can  then 
be  cut  into  pellets  of  convenient  length. 

(3)  Cylinders  or  blocks  can  be  bought  ready 
made. 


371 


The  second  method  has  several  advantages 
over  the  others ;  the  pellets  are  very  easy  to 
make,  they  can  be  of  any  degree  of  tiglitness 
or  looseness,  thickness  or  length,  and  can  be 
made  of  the  most  cohesive  foil  that  can  be 
obtained. 

Thick  or  "  hea\'y  "  foil  has  the  advantage 
that,  instead  of  gaining  substance  by  folding, 
it  is  all  ill  one  piece,  and  the  resultuig  filling 
is  so  much  the  more  solid.  Nos.  40  and  60  are 
very  convenient  sizes  of  thick  foil ;  they  are 
sufficiently  flexible  to  permit  rapid  and  easy 
work,  provided  care  is  taken  in  the  lammation, 
and  each  layer  is  condensed  before  the  applica- 
tion of  the  next  one.  Heavy  foU  is  most  suitable 
for  use  on  comparatively  flat  or  convex  surfaces, 
and  especially  for  forming  the  actual  working 
face  of  a  fiUing,  and  in  these  situations  its  use 
wfll  permit  the  condensation  of  a  greater 
quantity  of  gold  m  a  given  time  than  if  pellets 
or  cylinders  are  employed. 

Gold  and  platinum  is  simUar  in  appearance 
and  working  properties  to  thick  gold  fofl ;  it 
consists  of  a  sheet  of  platinum  coated  on  both 
sides  with  gold.  The  presence  of  the  platmum 
renders  the  foil  stififer  to  work,  lighter  in  colour 
when  polished,  and  much  harder,  and  hence 
better  adapted  to  withstand  heavy  wear ; 
dift'erent  grades  are  supplied,  the  lighter  and 
harder  ones  naturally  being  those  contaming 
most  platinum.  The  lightness  of  colour  would 
seem  to  be  an  advantage,  and  if  seen  at  a 
certain  angle  a  gold  and  platinum  fillmg  may 
be  almost  invisible,  but  if  seen  in  other  lights 
it  shows  up  quite  as  much  as  gold,  if  not  more  so. 
Gold  and  iridium  is  still  harder,  but  in  other 
respects  is  very  similar  to  gold  and  jilatinum. 

Crystal  or  mat  gold  is  not  made  by  rolling 
or  beating,  but  is  chemically  deposited  as  a 
spongy  mass  of  minute  crystals.  It  does  not 
look  like  gold  at  all,  but,  when  properly  con- 
densed, the  particles  weld  together  into  a  hard 
mass  quite  indistinguishable  from  one  made 
from  any  other  kuid  of  gold ;  in  fact  one  of  the 
hardest  test  iiUings  the  ^^Titer  ever  made  ^^'as 
composed  of  crystal  gold  from  beginning  to 
end.  Bulk  for  bulk,  crystal  gold  is  heavier 
than  ordinary  cylinders.  It  is  very  cohesive, 
and  for  this  reason  is  useful  when  there  is  any 
difficulty  about  the  cohesion,  as  for  instance 
in  patching  an  old  fUling.  Owing  to  its  density 
and  cohesiveness  it  requires  great  care  in  its 
condensation;  if  too  much  is  put  on  at  once, 
the  plugging  instrument  is  rather  liable  to 
form  a  hard  cake  on  the  surface  and  leave 
soft  places  in  tlie  interior.  Gold  and  platinum 
is  also  obtainable  in  mat  form  and  is  similar 
to  mat  gold  in  its  working  properties. 

It  is  an  excellent  plan  to  use  all  three  kinds  J 
of   gold  in  one  fiUing,  mat   for  small  pits  and 
angles,  pellets  for  the  mam  part  of  the  cavity. 


and  towards  the  end,  peUets  and  foil  alternately, 
finishing  up  with  foil  alone. 

Annealing. — In  order  to  develop  to  its  fullest 
extent  the  all-important  quality  of  cohesiveness, 
gold  requires  to  undergo  the  process  cal.'el 
annealing.  It  may  be  noted  that  the  term 
"  cohesiveness  "  is  used  to  indicate  the  property 
of  welding  that  is  possessed  by  cohesive  gold ; 
it  does  not  mean  the  same  thmg  as  "  cohesion  ", 
which  is  the  force  of  attraction  between  adjacent 
molecules  in  the  substance  of  the  metal.  Al- 
though caUed  "-annealing  ",  this  process  is  not 
to  be  confounded  with  the  operation  of  heatmg 
to  relieve  internal  strains,  which  is  largely  used 
in  various  kinds  of  metal  work,  although  it  is 
quite  possible  that  there  hiay  be  some  kind  of 
molecular  rearrangement,  such  as  the  formation 
or  alteration  of  crystaUme  structure  in  the 
metal. 

It  is  found  that  heatmg  to  redness,  or  in 
some  cases  to  a  point  far  below  that  tempera- 
ture, will  render  some  specimens  of  gold  cohesive 
that  were  not  so  before  that  treatment.  This 
property  is  impaired  or  destroyed  by  any 
obvious  contamination,  such  as  soot,  grease, 
or  even  moisture.  Exposure  to  certain  gases, 
especiaUy  ammonia,  will  produce  the  same 
effect,  and  "  amiealing  "  in  all  probability 
consists  in  great  part  in  dissipating,  any  film 
or  layer  that  may  have  formed  on  the  surface 
of  the  gold ;  or  it  may  be  that  the  heat  decom- 
poses some  loose  chemical  combmation  between 
the  gas  and  the  surface  layer  of  the  metal. 
Other  substances  besides  ammonia,  namely, 
hydrogen,  sulphur  dioxide,  phosphuretted  hy- 
drogen, and  chlorine,  are  said  to  have  deleterious 
effects  on  the  cohesive  properties  of  gold. 

The  question  arises  M'hether  gold  can  be  an- 
nealed too  much  ;  many  good  operators  believe 
that  annealing  beyond  a  certam  point  is  detri- 
mental to  the  workmg  jiroperties,  especially  of 
crystal  gold,  but  actual  experiment  faUs  to 
demonstrate  any  lessening  of  cohesive  qualities 
by  heating  to  any  temperature  sliort  of  the 
fusion  point.  The  explanation  perliaps  lies  in 
the  fact  that  for  certain  kinds  of  work,  such  as 
the  building  up  of  a  large  filling  that  is  not 
likely  to  be  subjected  to  violent  strains,  the 
gold  can  be  condensed  more  easily  and  more 
rapidly  if  used  in  large  pellets  and  in  what 
may  be  called  a  "  semi-cohesive  "  state.  Thick 
foil  is  certamly  at  its  best  after  being  heated  to 
redness. 

Tliere  are  three  methods  of  annealing  in 
common  use. 

(1)  Holding  each  Piece  over  the  Flame. 
Although  much  used  this  plan  is  not  to  be 
recommended  ;  it  wastes  valuable  time,  the  gold 
is  liable  to  be  fused  or  else  to  escape  heating 
altogether,  and  if  the  flame  is  not  a  clean  one 
it  may  cause  trouble  by  deposition  of  soot. 


372 


(2)  Heating  on  a  Sheet  of  Mica,  or  better  still 
Platinum  Foil,  held  over  a  Flame. — This  is  an 
excellent  method;  the  heat  is  uniform,  and 
much  time  may  be  saved  by  having  an  assistant 
to  keep  the  heating  tray  charged  with  gold, 
so  that  the  operator  has  nothing  to  do  but 
pick  it  oflf.  Thick  foU  is  liable  to  be  under- 
annealed,  unless  a  strong  flame  is  used  for 
heating  the  tray. 

(3)  Annealing  on  an  Electrically  Heated  Slab. 
This  method  differs  from  the  last  only  in  the 
source  of  the  heat,  and  experience  of  both  shows 
that  there  is  little  to  choose  between  them ; 
no  contamination  of  the  gold  is  possible  with 
either. 

Condensation  of  Gold. — On  trial  it  is  found 
that  good  specimens  of  cohesive  gold  require 
very  little  pressure  to  make  them  cohere ;  it 
seems  as  if  the  mere  bringing  them  into  contact 
with  one  another  is  sufficient  for  the  purpose. 
In  the  condensation  of  a  filling,  however,  a 
certain  amount  of  pressure  is  required  to  bring 
the  different  layers  into  contact  over  as  great 
a  part  of  their  surface  as  possible,  so  as  to 
obliterate  air  spaces  that  would  otherwise  form 
weak  places  in  the  fiOing.  The  degree  of 
condensation  can  be  measured  by  the  specific 
gravity,  wliich,  in  an  ordinary  filling,  may  be 
about  sixteen.  The  necessary  pressure  may 
be  produced  by  hand  instruments,  or  by  various 
kinds  of  mallets,  actuated  by  hand  or  driven 
mechanically.  These  methods  differ  consider- 
ably from  one  another,  and  each  has  its 
advocates,  M'ho  believe  it  to  be  the  best  way 
to  condense  a  filling ;  they  are  all,  however, 
only  so  many  means  of  exercising  force  to 
produce  pressure,  and  can  be  compared  with 
one  another  if  in  each  case  are  known  the  point 
of  application  of  the  force,  its  direction,  its 
magnitude,  and  the  time  during  which  it  is 
applied.  These  various  data  may  be  considered 
separately. 

(1)  Point  of  Application. — In  this  respect 
hand  pressure  certainly  has  some  advantage, 
but  users  of  the  right-angle  engine-mallet  and 
the  back  action  of  the  automatic  will  find  that 
there  are  very  few  points  in  any  reasonably 
shaped  cavity  that  cannot  be  reached  by  one 
or  other  of  these  instruments. 

(2)  Direction. — Here  hand  pressure  is  easily 
first  as,  with  appropriate  finger  manipulation, 
the  gold  can  be  condensed  towards  the  cavity 
wall,  whether  the  direction  be  towards  the 
operator,  away  from  him,  or  somewhere  be- 
tween these  two.  It  is  a  mistake,  however, 
to  suppose  that  the  force  of  a  mallet  blow  is 
limited  entirely  to  the  direction  of  the  shaft 
of  the  instrument,  and  that  therefore  the 
striking  face  must  always  be  at  right  angles 
to  the  shaft.  If  the  face  is  set  at  some  other 
angle,  the  force  can  always  be  considered  as 


resolved  into  two  components ;  one  of  these 
acts  vertically  to  the  striking  face  and  con- 
denses the  gold  in  that  direction ;  the  other 
tends  to  push  the  face  of  the  plugger  along 
the  surface  of  the  gold  ;  this  tendency  is  resisted 
by  the  serrations,  which  are  quite  sufficient  to 
keep  the  instrument  steady,  unless  it  is  much 
worn  or  the  angle  is  too  great.  As  the  serra- 
tions transmit  this  lateral  pressure  to  the  gold 
itself,  care  must  be  taken  that  its  direction  is 
always  towards  a  cavity  wall  rather  than  away 
from  it. 

(3)  Magnitude. — Strictly  speaking,  the  con- 
densing effect  does  not  depend  on  the  total 
pressure,  but  on  the  pressure  per  unit  area. 
Hence  a  small  point  will  condense  better  than 
a  large  one,  the  effect  being  in  inverse  propor- 
tion to  the  area  of  the  working  face  ;  a  diameter 
of  '75  mm.  will  be  found  large  enough  for  most 
work.  If  the  working  face  is  not  at  right 
angles  to  the  shaft,  the  proportion  of  the  useful 
component  will  be  represented  by  the  sine  of 
the  angle  they  make  with  one  another ;  thus, 
if  the  serrated  face  is  inclined  to  the  shaft  at 
an  angle  of  C0°,  the  useful  pressure  will  be 
rather  more  than  eight-tenths  of  the  whole. 

The  pressure  required  for  condensation  will 
vary  with  the  stiffness  of  the  gold  and  the 
thickness  of  the  pellet  used.  Black's  opinion 
is  that  15  lb  per  sq.  mm.  is  about  the  most 
useful  amount,  but  this  statement  must  be 
read  in  connection  with  the  rest  of  his  work 
on  gold  manipulation,  where  much  valuable 
information  wHl  be  found. 

The  amount  of  pressure  exercised  with  hand 

\  instruments  can  easily  be  found  by  making  a 

test  filling  in  a  tooth  fixed  on  the  pan  of  a 

!  spring  balance.     "  Light  "   pressure   would  be 

about  two  or  three  pounds,  "  ordinary  "  might 

I  be   from   about   seven   to   twelve,   while    most 

operators — and  patients — would  class  pressures 

of  fifteen  pounds  and  upwards  as  "  heavy". 

It  is  more  difficult  to  estimate  the  force  of  a 
mallet  blow  because  the  pressure  depends  not 
only  on  the  amount  of  energy  in  the  moving 
hammer,  but  also  on  the  nature  of  the  resist- 
ance that  brings  it  to  rest.  The  work  done 
by  a  force  is  proportional  both  to  the  force 
and  to  the  distance  through  which  it  acts. 
In  this  case  the  work  done  by  the  resistance 
is  always  equal  to  that  stored  in  the  moving 
hammer,  and  the  distance  through  which  the 
resisting  force  acts  is  the  very  small  one  the 
hammer  travels  after  commencing  to  strike  its 
blow  ;  the  force  of  resistance  must  in  consequence 
be  proportionally  large,  and,  as  action  and 
reaction  are  equal,  this  force  will  be  the  same 
as  the  pressure  caused  by  the  blow.  Of  all 
the  mallets  the  automatic  most  readily  lends 
itself  to  estimations  of  this  kind.  In  this 
instrument  the  blow  is  given  by  a  small  steel 


373 


hammer  which  weighs  an  ounce  or  less ;  this 
hammer  is  actuated  by  an  adjustable  spring, 
the  force  of  which  at  the  moment  of  release 
can  readily  be  found  by  pressing  the  point  of 
the  instrument  on  a  dynamometer  or  spring 
balance.  The  distance  through  which  the 
force  acts  is  about  one-eighth  of  an  inch,  and 
if  the  force  of  the  spring  is  two  pounds,  the 
work  imparted  to  the  hammer  will  be  one- 
forty-eighth  of  a  foot-pound ;  if  the  hammer 
is  brought  to  rest  in  the  hundredth  part  of  an 
inch,  the  pressure  produced  will  be  25  lb., 
leaving  out  of  account  the  loss  of  energy  due 
to  transformation  into  heat  and  production 
of  vibrations.  Other  mallets  are  somewhat 
similar  in  prmciple,  but  do  not  so  readily  lend 
themselves  to  calculation. 

If  accurate  knowledge  of  the  pressure  is 
required,  it  can  be  obtained,  as  indicated  by 
Black,  by  measuring  the  depth  of  the  indent 
made  by  the  point  of  the  plugging  instrument 
into  the  gold.  In  practice  the  '"  feel  "  of  the 
blow  will  enable  the  operator  to  judge  with 
sufficient  accuracy  whetlier  the  pressure  is 
satisfactory,  or  too  great,  or  too  small.  The 
important  fact  is  that  a  small  hammer  can 
produce  quite  a  considerable  jiressure,  and  this 
explains  why  a  mallet  is  such  an  efficient  instru- 
ment for  condensing  gold,  and  also  %\hy  it  is 
so  destructive  to  enamel  in  case  of  a  false  stroke. 

(4)  Time. — Time  is  of  some  importance  be- 
cause the  layers  of  gold  take  a  certain  definite, 
though  small,  time  to  bend  and  get  into  a]3posi- 
tion  with  one  another.  Hand  pressure  differs 
markedly  from  that  produced  by  a  mallet 
blow  in  that  it  can  be  kept  up  for  an  indefinite 
time,  and  that  is  why  it  is  used  almost  ex- 
clusively in  working  non-cohesive  gold,  which 
is  condensed,  not  piece  by  piece,  but  rather  en 
masse.  Mallet  pressure,  while  greater  in 
amount,  lasts  but  a  very  short  time,  which 
may  be  slightly  lengthened  by  any  condition 
that  lessens  the  resistance,  such  as  the  leaden 
striking  face  of  certain  hand  mallets.  With 
some  of  the  mechanical  mallets  the  pressure 
rises  to  its  maximum  and  falls  again  to  zero  so 
rapidly  that  unless  a  number  of  blows  are  given 
in  the  same  place  only  the  surface  layers  will 
get  condensed  at  all ;  in  common  language,  the 
blow  lacks  "  penetration  ".  This  kind  of  mallet 
is  at  its  best  when  layer  after  layer  of  thick 
foil  is  being  applied,  and  for  this  purpose  is 
unrivalled  both  for  efficiency  and  rapidity  of 
working. 

Non-cohe.sk'e  Gold. — Tlie  manipulation  of  non- 
cohesive  gold,  although  requiring  a  considerable 
degree  of  dexterity,  is  a  simple  matter  in  prin- 
ciple. A  filling  made  of  this  material  is  com- 
posed of  a  number  of  separate  pieces ;  these 
must  be  of  fair  size  or  the  filling  would  dis- 
integrate, and  they  must  also  be  flexible  enough 


to  allow  of  close  packing.  Hence,  faii'ly  thin 
foil  is  the  only  form  of  non-cohesive  gold  that 
is  of  use  for  filling  teeth,  and  the  individual 
layers  should  be  parallel  to  one  another  and 
to  the  walls  of  the  cavity,  and  should  extend 
the  whole  depth  of  the  filling.  These  conditions 
are  most  easily  realized  by  the  use  of  tightly 
rolled  ready-made  cylinders ;  but  rope  and 
folded  strips  can  be  employed,  and  produce 
perfectly  good  practical  results  in  the  hands  of 
those  accustomed  to  their  use.  The  dis- 
tinguishmg  feature  of  non-cohesive  gold  is  that, 
owing  to  the  sliding  of  the  layers  upon  one 
anotlier,  the  degree  of  condensation  of  the  mass 
keeps  increasing  up  to  the  end  of  the  operation. 
Hence  the  apposition  of  the  gold  to  the  cavity 
margin  grows  better  as  the  filling  proceeds, 
and  it  is  a  fact  that  it  is  easier  to  get  a  water- 
tight joint  with  non-cohesive  than  w  ith  cohesive 
gold. 

The  same  principles  govern  the  manipulation 
of  tm,  and  tin  and  gold.  Both  can  be  obtained 
in  ready-made  blocks  or  cylinders,  but  very 
convenient  blocks  of  tin  and  gold  can  be  made 
by  the  operator  himself ;  one  sheet  of  tin  is 
placed  between  two  sheets  of  No.  4  gold,  the 
combined  sheet  is  then  cut  into  strips  about 
J  in.  wide,  and  each  strip  rolled  into  a  rope 
and  then  folded  "  cracker- wise  "  into  a  cubical 
block.  Gold-and-tin  sometimes  undergoes  a 
change  in  the  mouth,  which  renders  it  somewhat 
more  brittle,  and  not  unlike  amalgam  in  texture. 
Miller  has  attributed  this  change  to  solution  of 
the  tin  and  redeposition  of  it  on  the  gold,  but 
in  view  of  Sir  William  Roberts-Austen's  experi- 
ments it  is  possible  that  the  gold  penetrates  the 
substance  of  the  tin,  the  close  apposition  under 
pressure  being  a  favourable  condition  for  this 
action  to  take  place  between  the  two  metals. 

J.  B.  P. 

BIBLIOGRAPHY 

(1)  Black,     G.     V.     Operative    Dentistry,     Vol.     II, 

pp.  229,  etc. 

(2)  Black,  G.V.  Dental  Cosmos,  1896,  Vol.  XXXVIII, 

pp.  303,  etc. 

(3)  Black,  G.  V.     Nature  of  Blows  and  Relation  of 

Size    of    Plugger   Points   to   Force   as   used   in 
Filling  Teeth.     Dental  Review,   1907,  p.   499. 

(4)  Carlson,  K.  E.     The  Problem  of  Condensation 

and  of  Specific  Gravity  of  Gold  Fillings.     Dental 
Review,  1907,  p.  523. 

(5)  Fenchel,  Carl.     Dental  Cosmos,  1909,  Vol.  LI, 

p.  1155. 

(6)  Haskins,    G.    W.     Use    of    Non-cohesive    Gold. 

Dental  Review,  1903,  p.  305. 

(7)  Hepbubn.     Dental  Record,  1908,  p.  303. 

(8)  Johnson,  C.  N.     Operative  Dentistry  (Article  on 

Gold). 

(9)  Roberts-Austen,  Sir  W.     Nature,  May  21,  1896, 

p.  55. 

(10)  Southwell,     C.     Methods     and     Principles     of 

Packing  Gold.     Dental  Review,  1907,  p.  904. 

(11)  Wedelst.aedt,  E.  K.     Methods  and  Principles  of 

Packing  Gold.     Dental  Review,  1907,  p.  896. 


CHAPTER  XXII 

FILLING    WITH    FOIL 


In  the  treatment  of  dental  caries  by  filling, 
gold  foil  was  for  many  years  considered  the 
most  satisfactory  material  available  for  the 
purpose.  So  exclusive  indeed  was  their  jjrefer- 
ence  for  gold  that  several  distinguished  operators 
of  the  past  generation  used  little  of  any  other 
material,  and  to  the  end  of  their  lives  refused 
to  use  amalgam.  The  general  experience  of  the 
dental  profession,  however,  tends  to  the  con- 
clusion that  neither  gold  nor  any  other  single 
filling  material  at  present  known  is  universally 
suitable  in  the  treatment  of  caries.  There 
being,  then,  no  ideal  or  universal  filling,  judicious 
choice  among  those  that  are  used  must  depend 
upon  a  proper  estimate  of  the  conditions  to  be 
dealt  with  in  each  case  or  class  of  cases. 

Improved  amalgams,  recently  devised  inlay 
methods,  or  artificial  crowns,  have  superseded 
the  larger  and  more  complex  foil  operations. 
But  there  is  still  an  important  class  of  cavities 
for  which  gold  foU  is  the  most  suitable  filling 
available ;  with  this  class  it  is  the  purpose  of  the 
present  chapter  to  deal.  Mention  of  cases  not 
suitable  for  foU,  or  better  treated  otherttdse,  and 
of  other  methods  than  foil  filling,  is  intended  to 
aid  the  reader  in  deciding  where  to  use  and 
where  not  to  use  foil — a  matter  quite  as  im- 
portant as  how  to  use  it. 


CAVITIES   FOR    WHICH    FOIL    FILLING 
SUITABLE 


IS 


1 .  Approximal  cavities  in  incisors  and  canines 
that  do  not  include  the  incisal  angle  or  much  of 
the  labial  enamel,  and  in  which  the  pulp  is  not 
exposed  though  lingual  enamel  may  be  more  or 
less  involved. 

2.  Pit  and  fissure  cavities  in  which  caries  is 
not  extensive  in  teeth  otherwise  sound. 

3.  Certain  labial  or  buccal  cavities  in  upper 
incisors,  canines,  and  premolars. 

4.  Small  approximal  cavities  in  premolars  or 
first  molars  in  which  the  filling  would  be  without 
approximal  contact,  owing  to  loss  of  a  tooth, 
e.  g.  a  medial  cavity  in  a  first  molar  or  a  distal 
cavity  in  a  first  premolar  where  the  second 
premolar  is  lost. 

Various  considerations,  including  an  operator's 
preference  for  the  material  or  method  tliat  he 
has  most  success  in  using,  will  determine  the 
choice  of  filling  in  certain  cases  not  defined  in 


374 


the  foregoing  classes.  Approximal  incisor  or 
canine  cavities  involving  a  considerable  amount 
of  labial  enamel,  or  even  the  incisal  angle ;  pit 
and  fissure  cavities  so  large  that  the  difficulties 
of  foil  or  of  gold  inlays  are  about  equal,  and 
certain  buccal,  or  labial,  or  approximal-occlusal 
cavities,  will  be  found  for  which  the  choice 
between  foil  and  other  fillings  should  depend 
upon  the  special  attendant  conditions  in  each 
case.  These  conditions  are  so  varied  that  they 
cannot  all  be  mentioned  ui  detail  [1  (d)]  [1  (e)]. 

Advantages  of  Gold  in  Class  1. — For  cavities 
of  this  class  the  fiUmgs  now  available  are  gold 
foU,  porcelain  inlay,  gold  inlay,  white  gutta- 
percha, and  the  various  cements. 

Of  the  cements  in  general  it  may  be  said  that 
they  are  fit  for  temporary  use  only.  Exposed 
to  the  fluids  of  the  mouth  they  are  more  or  less 
liable  to  solution  or  erosion.  They  are  irritating 
to  the  gum  when  in  contact  with  it,  and  are 
especiall}'  liable  to  solution  or  leakage  at  the 
gingival  margin.  They  are  apt  to  waste  at  the 
surface,  thus  losmg  contour,  to  the  detriment 
of  the  gum  septum  and  the  regularity  of  the 
arch. 

For  cavities  of  this  class  in  the  teeth  of  young 
children,  or  of  boys  or  ghls  whose  teeth  show 
marked  susceptibility  to  caries,  white  base-plate 
gutta-percha  properly  inserted  and  finished  is 
altogether  superior  to  the  cements.  This 
material,  while  not  faultless,  has  been  found 
to  do  good  service  for  years ;  or  until  comparative 
immunity  from  caries,  or  adult  age,  indicates 
other  filling  more  suitable  to  the  changed 
conditions. 

The  gold  inlay  will  not  in  these  cases  econo- 
mize either  time  or  tooth  tissue.  Wider  separa- 
tion is  necessary  for  inlay  work  m  these  cavities 
than  for  foil  filling,  and  when  finished  in  this 
situation  a  gold  inlay  is  not  necessarily  superior 
to  a  foil  filling. 

The  porcelain  inlay  for  such  a  case  will 
require  either  wide  separation  of  the  teeth,  or 
an  otherwise  needless  cutting  away  of  lingual 
or  labial  enamel.  Its  retention  is  not  easOy 
made  secure,  and  in  any  case  washing  away 
of  cement  from  the  joints  may  be  regarded  as 
likely  to  occur.  Few  small  porcelain  inlays  in 
these  situations  have  an  appearance  wholly 
satisfactory ;  indeed  the  aesthetic  result  is  in 
many  cases  inferior  to  what  might  be  secured 


375 


with  gold.  A  small  but  visible  margin  of  gold 
in  contrast  with  enamel  in  a  well-inserted  fiJlLng 
is  more  satisfactory  to  the  eye  than  is  any  aspect 
of  a  porcelain  inlay  which  raises  a  doubt  in  the 
mind  of  the  observer  [1  (d)].  For  certain  incisor 
cavities  outside  the  class  here  considered, 
however,  porcelain  inlays  are  for  aesthetic 
reasons   to    be   preferred. 

Durability,  adaptability,  edge-strength,  and 
cleanliness,  are  the  qualities  that  render  gold 
suitable  for  the  cavities  in  question.  For  its 
insertion  the  rubber-dam  is  necessary ;  but  this 
is  more  easily  adjusted  and  retained,  and  is 
worn  with  less  discomfort,  upon  the  upper 
incisors  than  upon  any  other  teeth.  Clamps 
are  not  necessary,  and  in  the  use  of  ligatures 
reasonable  care,  and  knowledge  of  the  anatomy 
of  the  teeth  and  adjacent  parts,  should  enable 
the  operator  to  use  the  rubber-dam  without 
causing  injury  [1  (/) ]. 

CASES    IN    WHICH    FOIL    FILLING    IS    NOT 
SUITABLE 

Generally  speaking,  gold  foU  should  not  be 
used  in  the  teeth  of  boys  or  girls  less  than 
fourteen  years  old.  The  pulp  in  the  teeth  of 
a  child  is  larger,  and  the  dentine  walls  surround- 
ing it  proportionately  thinner,  than  will  be  the 
case  later  in  life ;  the  tissues  of  the  teeth  are  at 
this  early  time  of  life  most  sensitive  to  irritation 
of  any  kind ;  support  of  the  root  is  not  yet  fully 
developed ;  and  children  should  not  be  subjected 
to  an  operation  so  likely  to  make  them  dread 
a  visit  to  the  dentist.  Girls  or  boys  in  their 
"  teens  "  whose  teeth  bear  evidence  of  unusual 
susceptibility  to  caries  are  unfavourable  for  foil 
fillmg.  The  teeth  are  sensitive,  the  cavities  are 
many,  and  the  recurrence  of  caries  is  j^robable. 

Foil  fiUing  should  not  be  undertaken  for  any 
person  in  a  state  of  health  too  weak  to  bear 
without  injury  such  pain  or  discomfort  as  may 
be  incident  to  the  proper  performance  of  such 
an  operation. 

Sore  or  loose  teeth,  attacks  of  caries  upon  the 
necks  of  teeth  after  recession  of  the  gum  in 
elderly  persons,  buccal  cavities  at  the  gum 
margin  in  molars,  large  or  compound  cavities 
in  any  of  the  lower  teeth,  situations  where 
application  of  the  rubber-dam  is  difficult  or 
injurious — in  none  of  these  cases  need  cavities 
be  filled  with  foil. 

For  large  or  conspicuous  cavities  in  or 
including  the  labial  surfaces  of  teeth  much 
exposed  to  view  the  colour  of  gold  is  objection- 
able. 

Pulpless  teeth  are  unfavourable  for  foil 
filling,  because  cavities  through  which  pulps 
are  exposed  by  caries  are  large,  while  the  cavity 
walls  are  tliin  and  weak,  often  consisting  only 
of  enamel  on  account  of  the  more  rapid  progress 


of  caries  in  the  dentine.  The  strain  upon  both 
patient  and  operator,  and  the  liability  of  such 
an  operation  to  failure,  justify  the  choice  of 
some  filling  other  than  foil  for  most  pulpless 
teeth.  Gold  or  porcelain  inlays,  or  amalgam, 
are  well  suited  to  these  cases.  Experience  shows 
that  pulpless  premolars  are  especially  apt  to 
discolour  or  split  after  even  careful  operations 
^\'ith  foil.  Lateral  stress  necessary  to  adapt  and 
condense  foil,  together  with  masticatory  stress 
afterwards,  seems  to  be  too  much  for  cavity 
walls  in  pulpless  premolars.  The  lameness  of 
pulpless  teeth,  or  their  diminished  toleration  of 
stress,  is  also  against  the  use  of  foil  in  them. 

SPECIAL  REQUIREMENTS   IN   THE   FORM    OF 
CAVITIES   FOR    GOLD 

In  outline  form  cavities  for  foil  are  prepared 
upon  the  principles  governing  cavity  prepara- 
tion in  general  (see  Chapter  XIX,  p.  344).  For 
convenience  the  form  of  cavity  must  be  such  that 
with  the  instruments  to  be  used  gold  may  be 
effectively  condensed  against 'all  walls  and  into 
all  angles  of  the  cavity.  The  form,  moreover, 
must  be  such  as  to  retain  the  first  portion  of 
gold  laid  from  one  wall  or  angle  to  the  opposite, 
when  condensed,  so  that  no  pressure  afterwards 
applied  wiU  tend  to  move  it. 

The  cavo-surface  angle  should  at  all  points 
be  so  bevelled  that  no  short  enamel  rods  \\ill 
remain  at  the  margin  exposed  to  fracture  or 
dislodgement  during  the  filling  operation  or 
afterwards.  Gold  has  greater  edge-strength 
or  toughness  than  has  amalgam,  porcelain,  or 
any  square-cut  margin  of  enamel ;  hence  the 
bevel  of  cavity  margins  for  gold,  whether  foil 
or  inlay,  may  be  more  attenuated  than  for  any 
other  filling.  The  advantages  of  bevelling, 
besides  the  protection  of  the  enamel,  are  the 
opportunity  to  secure  complete  closure  of  the 
joint  by  burnishing  the  knife-like  edge  of  gold 
agamst  the  bevelled  enamel,  and  also  tlie 
conservation  of  tooth  tissue  ^^■hen  extending 
the  outlines  of  the  filling  to  immune  areas. 

For  foil  filling  especially,  it  is  necessary  to 
change  that  rounded  form  of  cavity  interior 
generally  found  after  removal  of  decalcified 
dentine  only;  such  a  form  is  unfavourable  for 
the  successful  insertion  of  a  gold  filling.  The 
interior  form  of  an  approximal  incisor  cavity 
is  corrected  by  making  the  line-angles  fairly 
definite  and  the  axial  wall  approximately  flat. 
The  labial,  lingual,  and  gingival  walls,  as  they 
approach  the  axio-gingivo-lingual  and  axio- 
gingivo-labial  point-angles,  should  be  slightly 
undercut  to  render  these  point-angles  fairly 
acute  for  retention  and  convenience  in  starting 
the  filling.  The  axio-incisal  angle,  and  that 
part  of  the  labial  wall  adjacent  to  it,  should 
be  slightly  undercut  to  complete  the  retentive 


37a 


form  of  the  cavity.  Grooving  or  undercutting  I 
of  labial  or  lingual  walls  throughout  their  length 
is  to  be  avoided  as  a  needless  weakening  of  these 
walls  and  a  menace  to  the  pulp.  All  walls,  as 
well  as  the  cavo-surface  bevel,  should  be  as 
smoothly  cut  as  possible,  to  allow  clo.se  adapta- 
tion of  the  gold  and  to  avoid  fracture  or  crum- 
bling of  the  cavity  surface  during  its  insertion  ^ 
[1(a)]. 

Ketention. — Since  the  use  of  cohesive  gold 
began,  various  methods  or  devices  for  the 
retention  of  fillings  have  from  time  to  time 
been  introduced,  only  to  pass  out  of  use  again 
as  soon  as  their  unfitness  was  recognized. 
Promment  among  these  was  the  screw ;  at 
some  point  in  the  cavity  the  screw  was  inserted 
in  a  hole  drilled  in  the  dentine,  or  in  a  pulpless 
tooth  it  was  set  in  the  pulp-chamber ;  the  gold 
was  built  about  the  head,  but  before  this  was 
altogether  covered  the  screw -driver  was  applied 
to  tighten  the  whole  in  the  cavity,  after  which 
the  remainder  of  the  filling  was  built.  Another 
now  obsolete  device  was  the  retention  "pit  "; 
pits  were  bored  tit  one  or  more  points  in  the 
cavity,  each  pit  was  fiUed  with  cohesive  gold, 
and  to  the  gold  protruding  from  these  the 
remainder  of  the  filling  was  welded.  Cements 
have  from  time  to  time  been  tried,  the  plan 
with  these  being  to  coat  the  interior  of  the 
cavity,  and  force  gold  against  the  wet  cement 
to  anchor  it  for  a  start,  and,  as  was  claimed, 
seal  the  joint  between  gold  and  tooth.  This 
cement  method  has  had  a  few  advocates  in 
recent  years  but  it  cannot  be  said  to  meet  with 
any  considerable  approval  (5).  For  reasons 
that  need  not  be  given  these  methods  of  reten- 
tion have  proved  unsatisfactory  and  may  be 
regarded  as  obsolete. 

At  the  present  time  the  only  recognized  means 
of  retention  for  foil  fillings  is  the  form  of  the 
cavity.  And  the  retentive  form,  as  distin- 
guished from  the  resistance  form,  is  secured  by 
making  at  least  two  opposing  walls  of  the 
cavity  quite  parallel  to  each  other  or  slightly 
undercut,  so  that  the  filling  when  made  'will 
be  a  little  larger  in  two  or  more  directions  in  the 
deeper  part  of  the  cavity  than  it  is  at  the 
orifice.  When  walls  are  strong  and  the  chances 
for  dislodgement  small,  the  resilient  grip  of 
parallel  dentine  walls  upon  properly  inserted 
gold  will  be  sufficient  without  undercuts ;  such 
is  the  case  in  pit  and  fissure  cavities  in  otherwise 
sound  teeth.  But  in  buccal,  labial,  or  approximal 
cavities  that  are  necessarily  shallow,  under- 
cutting is  necessary  both  for  retention  and 
convenience  in  the  insertion  of  gold.  Excessive 
undercutting  is,  however,  to  be  avoided,  as  it 
weakens  cavity  walls  and  increases  the  diffi- 
culties of  adaptation  ^\-ithout  affording  any 
advantage.  For  a  labial  cavity  an  inverted- 
cone  burr,  used  with  its  base  parallel  with  the 


axial  wall  or  floor  of  the  cavity,  will  undercut 
the  walls  to  about  the  proper  degree  [1  (b)]. 
The  use  of  the  pulp-chamber  for  retention  is 
permissible  in  case  a  pulpless  lateral  incisor  is 
to  be  filled  with  foil.  The  larger  teeth  when 
pidpless  are  unsuitable  for  foil,  as  elsewhere 
mentioned. 

Lining  Cavities  with  Cement. — It  is  desirable, 
especially  in  cavities  that  closely  approach  the 
pulp,  to  interpose  some  non-conductor  between 
gold  and  dentme  to  protect  the  pulp  from 
thermal  irritation.  In  the  deeper  cavities 
cement  may  be  used  for  this  purpose  with 
advantage.  In  shallow  cavities,  however,  its 
use  is  more  difficult  and  the  result  less  certain, 
as  the  neces-sarily  thin  layer  of  cement  is  likely 
to  be  more  or  less  pulverized  by  pressure  of 
pluggers  in  working  gold  against  it,  unless 
particular  skill  and  care  are  exercised  [15(c)]. 
When  cement  linmg  is  to  be  used,  the  cavity 
is  dried  after  the  removal  of  decalcified  tissue, 
cement  in  an  adhesive  state  is  introduced,  and 
at  the  proper  stage  of  setting  packed  so  as  to 
allow  no  air  spaces.  In  completing  the  prepara- 
tion of  the  cavity  for  gold  the  cement  is  cut 
away  only  where  necessary ;  no  cement  should 
be  allowed  to  remain  upon  the  prepared  enamel 
margins.  The  practice  elsewhere  mentioned  of 
immediately  packing  gold  upon  a  plastic  or  unset 
lining  of  cement  is  likely  to  be  uncertain  in 
results,  except  perhaps  in  cavities  of  unusual 
retentive  form.  Movement  of  the  gold  under 
pressure  of  jikiggers  ■\\'ould  be  likely  to  break 
the  desired  adhesion  between  gold  and  cement 
and  leave  the  latter  in  a  more  or  less  pulverized 
state.  The  friability  of  cement  would  seem  to 
discourage  reliance  upon  it  for  use  in  this  way, 
especially  in  the  absence  of  any  general  approval 
warranted  by  experience. 

Combination    of    Gold     with    Amalgam    or    Tin : 
Reasons  for  Disuse  of  these  Combinations 

No  advantage  is  secured  by  the  combination 
of  gold  foil  with  amalgam  as  a  filling.  The 
objectionable  qualities  of  an  amalgam  will 
assert  themselves  whether  gold  is  used  with 
it  or  not.  Stain  of  the  tooth  or  unsatisfactory 
colour  of  the  filling  are  not  avoided  by  combinmg 
these  materials,  for  gold  in  the  same  cavity  with 
amalgam  usually  assumes  a  black  or  tarnished 
appearance.  If  shrinkage,  expansion,  or  flow 
under  stress,  be  a  fault  of  the  amalgam  used,  the 
addition  of  gold  ^^  ill  not  prevent  either  of  the 
two  former,  and  will  prove  but  a  partial  or  un- 
certain remedy  for  the  last.  The  best  amalgam 
in  a  plastic  state,  or  in  the  course  of  setting, 
would  make  an  insecure  foundation  upon  which 
to  build  gold.  The  tendency  of  amalgam  when 
not  completely  crystallized  or  set  is  to  move  or 
change  form  under  such  stress  as  is  used  in  the 
condensation  of  gold.     Amalgamation  of  gold 


377 


in  the  surplus  mercury  of  freshly  inserted 
amalgam  would  be  a  little  worse  than  waste  of 
time  and  gold,  for  the  result  would  be  less  certain 
than  it  would  be  by  the  use  of  amalgam  alone. 
"  No  advantage  ^^■llatever  is  derived  from  adding 
gold  or  platinum  to  (amalgam)  alloys,  but  so 
long  as  these  are  used  very  sparingly  they  do 
not  do  much  harm." — Black  [1(c)]. 

Tin  foil  in  the  gingival  portion  of  approximal 
cavities  to  be  filled  with  gold  was  used  many 
years  ago.  The  method  is  little  if  at  all  used 
now  and  may  be  neglected  for  the  purposes  of 
this  chapter  [1(e)]. 

A  combination  of  gold  and  tin,  made  by 
rolling  together  a  slieet  of  gold  foil  and  a  sheet 
of  tin  foil  of  equal  size  to  form  a  rope,  was  used 
for  the  gingival  third,  or  sometimes  half,  of 
large  approximal  cavities  in  molars  or  pre- 
molars where  not  exposed  to  view.  The  sheets 
of  foil  were  cut  so  as  to  have  the  rope  of  con- 
venient size.  One  end  of  the  rope  was  inserted 
in  the  cavity  (to  which  a  matrix  was  previously 
fitted),  and  by  firm  thrusts  of  a  large  plugger 
the  desired  quantity  was  inserted,  but  not 
entirely  condensed  at  the  surface.  The  rope 
was  then  broken  off,  and  cohesive  or  semi- 
cohesive  gold  thrust  into  tlie  tin  combination 
with  small  pluggers  until  a  welding  surface  ^^'as 
secured,  and  tJie  filling  finished  with  gold  (6), 
[!!(/«)],  (14).  The  g  od  and  tin  combination 
proved  superior  to  tin  alone,  but  it  turns  black 
and  becomes  brittle  in  the  mouth. 

WTien  amalgam  alloys  were  less  reliable  than 
they  are  now,  and  no  practicable  inlay  method 
was  generally  kno^^'n  or  in  use,  these  combina- 
tions %\ere  useful  or  necessary.  But  they  may 
now  be  considered  to  be  superseded,  and  so 
likely  to  pass  out  of  use  that  further  discussion 
of  their  uses  or  merits  may  be  omitted. 

Disadvantages  of  Filling  Materials  or  Methods  that 
require  Application  of  the  Rubber-dam 

Any  method  or  material  for  the  restoration  of 
carious  posterior  (especially  lower)  teeth  that 
does  not  necessarily  require  application  of  the 
rubber-dam  has  an  advantage  over  foil  filling 
not  to  be  ignored  or  underestimated.  Besides 
the  inconvenience,  discomfort,  or  pain,  suffered 
by  the  patient,  and  the  time  and  energy  sj^ent 
by  the  operator  in  the  adjustment  and  retention 
of  the  rubber-dam,  there  is  in  many  cases  a  more 
serious  objection  to  its  use.  Cavities  extending 
to  the  gum  margin  or  bej'ond  it  commonly 
require  the  use  of  clamps  or  ligatures,  or  both, 
to  retain  the  rubber.  These  devices  must  be 
placed  beyond  the  margin  of  the  cavity,  thus 
dangerouslyencroaching  upon  the  pericementum, 
alveolar  process,  and  gum.  That  these  tissues 
do  not  readily  recover  from  such  injuries  as 
clamps  and  ligatures  are  apt  to  inflict,  is  now 
more   widely  known  than  it  was  a  few  years 


ago  (2).  The  difficulty  of  using  clamps  and  liga- 
tures in  these  cases  without  doing  injury  is 
not  yet  so  commonly  recognized  as  it  should 
be  [!(/)]. 

Gold  or  other  foils  cannot  be  successfully  used 
without  the  total  exclusion  of  moisture  from  the 
field  of  operation.  But  golel  inlays  or  amalgams 
can  be  used  without  such  long-sustained  exclu- 
sion of  moisture  as  would  require  the  rubber- 
dam,  and  in  this  respect  have  a  very  important 
advantage  over  foil. 

Foil  filling  superseded  in  Ajjproximo-occliisal 
Cavities. — In  the  treatment  of  approximal  caries 
in  molars  and  premolars  foil  filling  was,  until  a 
short  time  ago,  the  standard.  The  principle  of 
"  extension  for  prevention  ",  i.  e.  the  extension 
of  cavity  margins  to  areas  of  enamel  compara- 
tively immune  from  decay ;  the  importance  of 
normal  contour  and  contact  point ;  the  necessity 
for  such  cavity  forms  and  strength  of  material 
as  will  resist  the  stress  of  mastication,  are  all 
now  recognized  as  essential,  and  insisted  upon 
by  the  foremost  operators  and  teachers  in  Great 
Britain  and  America.  Until  recently  gold  foil 
was  found  more  nearly  to  meet  these  require- 
ments than  did  any  other  material  available. 
Now  ho\\ever  these  j^rinciples  can  be  put  in 
practice  by  means  of  the  cast  inlay  with  less 
waste  or  weakening  of  the  tooth,  less  pain  or 
discomfort  to  the  patient,  more  certainty  of 
contour  and  contact  point,  and  greater  strength 
to  resist  stress  in  mastication,  than  was  the  case 
with  gold  foil.  For  some  cavities  in  posterior 
teeth,  in  circumstances  not  at  all  uncommon, 
good  amalgam  has  advantages  over  either  foil 
or  inlays. 

The  disadvantages  of  foil  filling  for  regular 
approximo-occlusal  cavities  in  molars  and  pre- 
molars— so  recently  regarded  as  standard — are 
these  :  the  necessary  use  of  the  rubber-dam,  the 
painful  procedures  in  cavity  preparation, thermal 
irritation  from  direct  contact  of  gold  with,  vital 
dentine,  and  the  unavoidable  tediousness, 
fatigue,  and  expenditure  of  time,  on  the  part 
of  patient  and  operator.  Operations  requiring 
such  patience  and  fortitude  are  unwelcome,  and 
tend  to  discourage  many  M'ho  %\'ould  otherwise 
prefer  conservative  treatment  of  their  teeth. 
On  the  other  hand,  the  less  painful  or  disagree- 
able dental  treatment  is,  the  greater  will  be  the 
number  willing  to  receive  it,  and  the  broader  %\ill 
be  the  public  usefulness  of  dentistry.  In  view 
of  these  considerations,  and  the  fact  that  foO- 
filling  of  approximo-occlusal  ca\-ities  is  fully 
described  in  recent  works  available  to  the 
reader,  such  description  will  be  omitted.  The 
probability  that  foil  will  generally  give  place 
to  the  cast  inlay  in  these  cases  is,  at  the  present 
stage  of  inlay  development,  so  strong  that  de- 
scription of  the  foil  method  may  here  be  regarded 
as  superfluous  [1  (n)],  [l(o)],  [16]. 


378 


MaUets 

Hand  Mallets. — -Where  malleting  is  required 
a  hand  mallet  used  by  a  trained  assistant  is  best. 
This  enables  the  operator  to  place  and  direct 
his  plugger  with  greater  facility  and  correctness 
than  any  other  kind  of  mallet  will  permit ;  he 
can  combine  hand  pressure  with  malleting,  or 
use  either  at  will,  as  the  work  may  require.  Of 
the  mallets  tried  by  the  writer,  which  were  of 
various  weights  and  materials,  including  steel, 
wood,  lead,  brass,  leather,  the  most  satisfactory 
seemed  to  be  a  steel  mallet  weighmg  650  grains, 
or  about  1^  oz.  Troy;  the  handle  should  be 
flexible  and  about  9  ins.  long.  A  jeweller's 
chasing  hammer  of  this  weight,  when  fitted 
with  the  proper  handle,  will  be  found  to  answer 
well  [11  (6)].  To  obtain  the  greatest  eflSciency 
in  transmitting  maUet  blows  to  the  gold,  the 
plugger  should  be  entirely  straight  from  point 
to  end  of  shaft,  and  no  heavier  than  necessary 
rigidity  requires.  Use  of  the  plugger  and  hand 
mallet  at  once  by  the  operator  is  a  slow  and 
difficult  procedure  [1(^)]. 

Automatic  Mallets. — Where  malleting  must  be 
done  without  the  aid  of  an  assistant  the  auto- 
matic mallet  may  be  used.  The  objections  to 
the  automatic  are  its  clumsiness,  and  the 
Liability  there  is  in  its  use  to  fracture  cavity 
margins,  unless  great  care  is  exercised.  The 
accurate  application  of  the  plugger  point  to  the 
spot  intended  at  each  stroke  is  more  difficult 
with  an  automatic  than  with  a  hand  plugger; 
hence  the  automatic  should  be  used,  it  at  all, 
only  to  condense  the  more  central  mass  of  the 
gold  in  a  filling,  including  of  course  the  surface 
when  the  cavity  is  full.  Right-angle  automatic 
or  engine  mallets  will  hereafter  be  so  seldom,  if 
ever,  needed  that  their  use  need  not  here  be 
described  [11  (c)]. 

Electric  and  engine  mallets  were  designed  to 
facilitate  the  building  and  condensation  of  large 
cohesive  gold-fiJlings.  Even  where  these  large 
restorations  were  undertaken,  the  majority  of 
competent  operators,  after  trial  of  both,  seem 
to  have  preferred  the  hand  mallet  used  by  an 
assistant.  As  tlie  large  foil  restoration  gives 
place  to  the  inlay,  interest  in  the  relative  merits 
of  the  various  mallets  diminishes  [1(A)]. 

Hand   Pressure 

Hand  pressure  has  many  advantages  in  the 
condensation  of  gold.  The  point  of  the  plugger 
is  placed  with  more  accuracy,  and  the  degree 
and  direction  of  the  force  applied  are  in  most 
cases  better  controlled  by  the  operator  when 
using  hand  pressure  than  when  using  automatic 
or  other  mallets.  The  use  of  hand  pressure 
develops  in  the  operator  a  discrimmative  sense 
that  is  hard  to  define  or  describe,  but  is 
of    great    advantage    in    the    manipulation    of 


gold ;  this  sense  of  touch  or  muscular  sense 
enables  the  trained  hand  to  feel  what  the 
operator  camiot  see.  The  impressions  thus 
conveyed  to  the  mind  through  the  mstrument 
in  hand  pressure  are  not  at  all  so  distinctly 
perceived  when  mallet  blows  are  used ;  for 
example,  an  operator  of  experience  cannot, 
when  using  hand  pressure,  scratch,  fracture, 
or  pulverize  a  cavity-wall  without  instantly 
knowing  it,  whereas  these  accidents  may  occur 
unnoticed  under  mallet  blows. 

It  is  therefore  best  to  use  only  hand  pressure 
in  filling  undercuts,  in  starting  a  filling,  or  in 
placing  or  condensing  gold  against  walls  or 
margins  liable  to  fracture.  Malleting  should 
be  done  only  where  walls  are  so  covered  as  to 
protect  them  from  contact  with  the  plugger. 
In  the  manipulation  of  gold  against  walls  by 
hand  pressure,  a  slight  swaying  motion  of  the 
shank,  and  consequent  rocking  motion  of  the 
point,  towards  the  wall  often  gives  better  control 
and  distribution  of  the  force  used,  and  is 
generally  more  effective  than  a  straight  thrust 
in  securing  good  adaptation.  Hand  pressure  is 
to  be  preferred  for  the  greater  part  of  the  gold 
used  in  cavities  in  the  incisors.  Indeed  it  may 
with  advantage  be  used  exclusively  in  the 
smaller  cavities  in  incisors  or  canines,  or  in 
any  situation  where  maUeting  is  not  convenient. 
The  disadvantages  of  hand  pressure  are  fatigue 
of  the  hand  and  delay  of  the  operation  where 
much  gold  is  to  be  used  [11  (<£)]. 

Matrices. — The  matrix  is  a  useful  and  almost 
indispensable  aid  to  the  proper  insertion  of 
amalgam  in  approximo-occlusal  cavities.  In 
distal  cavities  of  this  class  the  matrix  was  used 
with  advantage  in  fUlmg  with  gold  foil  or  with 
gold  and  tin.  In  medial  cavities  however  the 
advantages  of  the  matrix  in  filling  with  gold 
are  largely  or  entirely  neutralized  by  the 
obstruction  it  offers  to  manipulation  and  to 
the  operator's  view  of  the  cavity.  In  filling 
incisor  or  other  cavities  now  considered  suitable 
for  foil  the  use  of  a  matrix  is  impracticable  or 
of  no  advantage  [11(/)],  (18). 

Instruments  used  in  Condensation  of  Gold. 
There  is  at  present  no  set  of  gold-pluggers 
recognized  or  uniformly  accepted  as  standard 
by  the  dental  profession.  The  forms  and  sizes 
of  pluggers  of  the  several  classes,  and  the  variety 
and  number  of  these  chosen  to  constitute  a  set 
sufficient  for  each  operator's  use,  seem  to  depend 
upon  individual  preference  or  upon  variations 
in  procedure  adopted  by  different  operators. 
However,  simple  forms  of  plugger  are  adapted 
to  the  simple  forms  of  cavity  now  usually  pre- 
pared, and  the  tendency  is  towards  uniform 
procedure  in  placing  and  condensing  gold,  and 
consequent  uniformity  in  sets  of  instruments 
selected  for  this  purpose  [1(^)1.  The  fewer  the 
instruments  used  in  an  operation,  the  less  will 


379 


be  the  delay  and  strain  upon  the  operator, 
provided  those  used  are  well  adapted  for  the 
work  to  be  done.  The  greater  the  variety  used, 
the  less  will  be  the  skill  in  using  each  individual 
instrument.  Hence  it  is  well  to  select  or  use 
the  smallest  assortment  that  will  include  the 
forms  and  sizes  necessary,  and  to  use  each 
instrument  for  all  the  work  to  which  it  is 
adapted,  changing  only  when  some  other  form 
or  size  is  clearly  necessary. 

The  instruments  shown  in  Fig.  442  are  of  forms 
found  efficient  by  the  writer  and  others  in  filling 
cavities  now  considered  suitable  for  foil.  These 
are  not  presented  as  standard  or  as  the  only 
forms  to  be  chosen,  but  merely  as  an  aid  to 
description  of  procedure.  Nos.  1  and  2  are 
used  for  filling  convenience-points  and  under- 
cuts, and  for  condensing  where  a  small  point 
and  hand  pressure  are  necessary ;  the  opposite 
curves  in  the  shanks  adapt  these  instruments 


Fig.  442. 

for  the  angles  of  cavities  where  fillings  are 
started,  and  also  for  the  use  of  one  in  each 
hand  in  certain  cases ;  their  face  diameter  is 
•5  mm.  The  rubber  finger-rests  shown  upon 
the  shanks  afford  an  efficient  and  comfortable 
"  pen  grasp  "  for  thrusting.  No.  3  is  a  -5  mm. 
right-angle  used  for  filling  incisal  undercuts 
where  thrusting  with  No.  1  or  No.  2  is  not 
convenient.  No.  4  is  a  larger  and  stronger 
right-angle,  -6  mm.,  and  may  be  used  with 
"  palm  and  thumb  "  grasp  in  distal  cavities  of 
the  left  side,  where  thrusts  or  mallet  blows  are 
not  conveniently  applied.  No.  5  has  a  flat  nib 
and  face,  -5  mm.  x  -8  mm.,  convex  in  its  long 
diameter ;  it  is  suitable  for  either  hand  pressure 
or  malleting,  or  both,  and  has  a  wide  range  of 
usefulness  in  building  agauast  walls,  and  in 
general  building  and  condensation  in  many 
forms  of  cavity.  No.  6,  round  face,  -8  mm.,  is 
used  with  hand  pressure  only.  No.  7  is  a  -6 
mm.  condenser,  to  be  used  for  hand  malleting 
only.     No.  8  is  serrated  on  both  sides,  and  is 


used  to  mould  fresh  pieces  to  place  in  buUding 
contour.  No.  9  is  the  well-known  Varney 
foot-plugger,  used  to  mould  and  shape  contour, 
and  condense  margms  or  surfaces  that  cannot 
otherwise  be  reached.  No.  10,  the  holding 
instrument,  having  a  similar  point  ■with  the 
opposite  curve  at  the  other  end,  is  used  to  hold 
the  first  piece  in  starting,  until  the  gold  is 
anchored  in  the  cavity. 

Uses  of  Various  Degrees  of  Cohesiveness. — For 
makmg  entire  fillings,  non-cohesive  gold,  i.  e. 
gold  that  will  not  cohere  or  weld  at  all,  is  now 
so  little  used  that  description  of  its  use  in  this 
way  may  be  omitted  (7).  On  account  of  its 
easy  adaptation  a  layer  of  non-cohesive  gold 
may  be  used  upon  the  gingival  or  the  labial 
wall  of  an  appro  ximal  cavity,  or  in  the  pulpal 
portion  of  a  deep  occlusal  cavity,  with  good 
results  when  the  rest  of  the  filling  is  made  of 
cohesive  gold.  To  adapt  gold  in  a  state  of 
maximum  cohesiveness  to 
cavity  walls  so  as  to  make 
a  moisture-tight  joint,  is 
more  difficult  than  to  do 
the  same  thing  uith  gold  in 
a  less  cohesive  state.  Since 
any  degree  of  cohesiveness 
less  than  the  maximum  can 
readily  be  secured,  it  will 
be  found  best  to  use  fully 
amiealed  gold  only  where  the 
strength,  or  resistance  to 
wear,  of  a  thoroughly  welded 
mass  is  necessary. 

In  most  cases  advantage 
will  be  gained  by  the  use 
of  slightly  annealed  or  semi- 
cohesive  pieces  in  contact 
with  the  walls,  and  fuUy 
cohesive  gold  only  in  the  main  or  central  body 
of  the  filling  and  at  the  surface  to  be  finished  (12). 
The  objection  to  non-cohesive  gold  is  that  no 
welding  occurs  between  it  and  cohesive  gold. 
Except  in  deep  cavities  or  those  of  the  most 
retentive  form,  such  as  occlusal  cavities  in 
molars,  any  considerable  mass  of  non-cohesive 
gold  will  be  liable  to  movement  during  manipula- 
tion ;  or,  in  other  words,  the  cavity  will  not  have 
a  sufficiently  firm  grip  of  the  partly  built  filling 
to  ensure  its  stability  during  the  operation  or 
afterwards.  Gold  in  a  semi-cohesive  state  can 
be  sufficiently  well  adapted  to  ^\'alls  and  angles, 
and  at  the  same  time  more  or  less  \\'elded  to  all 
the  gold  in  the  fillmg.  The  proportion  of  non- 
cohesive  or  semi-cohesive  to  fully  cohesive  gold 
thus  used  in  a  filling  must  be  determined  by 
the  operator  in  each  case.  To  secure  the  best 
results  this  proportion  will  depend  upon  the 
situation  and  form  of  the  cavity,  the  retention 
available,  and  the  stress  to  which  the  filling  will 


be   exposed.     The 


greater 


the    stress    tending 


380 


to  dislodge  the  filling,  or  the  less  secure  the 
available  retention,  the  more  should  be  the 
cohesive  gold  used,  and  vice  versa.  Fillings 
exposed  to  no  stress  at  all  are  much  more  easUy 
and  quickly  buUt  with  gold  in  a  state  of  minimum 
cohesiveness.  Only  the  surface  of  such  fillings 
need  be  of  fully  cohesive  gold;  this  should,  how- 
ever, be  added  before  the  gold  against  which  it  is 
placed  is  entirely  condensed.  In  other  words, 
the  cohesive  gold  should  be  forced  into  the  semi- 
cohesive  or  non-cohesive  so  as  to  be  interlocked 
or  matted  with  it ;  this  operation  is  performed 
best  by  hand  pressure. 

Hints  on  Working  Gold 

Though  it  is  generally  preferable  to  use  the 
foil  pliers  to  pick  up  pellets  and  place  them  in 
the  cavity,  it  will  often  economize  time  and 
energy  to  pick  up  the  gold  with  the  plugger. 
Pellets  of  gold  laid  upon  a  sheet  of  clean  spunk 
kept  for  the  purpose  may  be  easily  and  neatly 
picked  up  with  the  end  of  the  plugger  without 
soiling  or  injuriously  condensing  the  pellet  in  so 
doing. 

Gold  can  be  overworked  by  repeated  applica- 
tions of  the  plugger,  so  that  the  cohesiveness  of 
its  surface  is  lost  and  the  welding  of  additional 
gold  to  it  rendered  difficult  or  impossible.  To 
add  gold  to  an  overworked  surface,  take  a  piece 
of  well-annealed  foil,  lay  it  flat  over  the  surface, 
and,  with  a  small  sharply  serrated  plugger  in 
each  hand,  hold  one  end  of  the  piece  with  one 
plugger  while  beginning  to  weld  at  the  opposite 
end,  and  stepping  the  plugger  to\^'ards  the  end 
that  is  being  held.  Should  this  fail,  use  a 
sharp  excavator  to  serrate  the  surface  deeply. 
Dust,  exhalations  from  the  skin  on  a  warm 
day,  or  the  patient's  breath,  may  quickly 
damage  the  welding  properties  of  gold.  Ex- 
cept when  moulding  large  pieces  of  gold  to 
place,  as  in  building  contour,  gold  should  not 
be  patted,  or  lightly  or  frequently  touched.  It 
is  a  good  plan,  however,  to  weld  two  or  more 
opposite  edges  of  a  fresh  piece,  as  may  be  done 
with  two  or  three  thrusts  of  the  plugger,  before 
beginning  the  regular  stepping  from  the  centre 
towards  the  walls.  The  ability  to  use  an  instru- 
ment in  each  hand  is  of  great  advantage  in  many 
operations,  but  especially  so  in  the  manipulation 
of  gold  foil.  A  reasonably  skilful  use  of  two 
instruments  at  once  not  only  prevents  rocking, 
curling  up,  or  movement  of  the  mass  in  the 
cavity  when  starting  the  filling,  but  facilitates 
rapid  progress  in  the  work  of  building  gold. 

The  gradual  appearance  of  stained  tooth 
tissue  surrounding  a  gold  filling  indicates 
leakage.  This  may  occur  on  account  of  faulty 
adaptation,  or  of  movement  of  the  filling  in  the 
cavity  after  part  or  the  whole  of  it  is  built. 
Such  failures  were  very  frequent  when  rounded 
cavities  and  "  retention  pits  "  were  used,  and 


also  \\here  the  entire  filling  was  made  of  cohesive 
gold  packed  with  the  automatic  mallet. 

Class  1. — Approximal  Cavities  in  Incisors  and 
Canines 
A  Case  for  Foil-filling. — In  Fig.  443,  cavities 
prepared  for  filling  are  sho^^•n  on  the  distal 
surface  of  a  right  central  and  on  the  medial 
surface  of  a  right  lateral  incisor.  These  cavity 
outlines  include  the  more  susceptible  areas  of 
the  surfaces  involved,  and  illustrate  cavity  forms 
suited  to  the  prevention  of  recurrent  caries  in 
susceptible  cases.  Widely  extended  cavities  are 
chosen,  because  the  insertion  of  foil  can  be  more 
clearly  illustrated  in  them  [l(m)].  Though 
the  extension  of  cavity  outlines  should  vary  in 
accordance  with  the  needs  of  each  case,  regular 
approximal  cavities  in  incisors  or  canines  should 
always  have  the  triangular  form  seen  in  the 
illustration.  Separation  of  the  teeth  should  be 
sufficient  to  allow  full  restoration  of  normal 
contour,  with  room  to  finish  without  destroying 
contact  points ;  such  separation  will  allow  labial 


Fig.  443. 

approach,  w'hich  is  to  be  preferred  ^^in  filling 
regular  or  typical  approximal  cavities.  In  the 
case  of  two  adjacent  cavities  one  should  be 
filled  and  finished  before  the  filling  of  the  other 
is  begun. 

To  fill  either  cavity  :  Place  a  large  pellet  or 
cylinder  of  semi-cohesive  gold  in  the  linguo- 
gingival  angle  so  as  to  reach  the  axial  wall  while 
protruding  beyond  the  enamel.  With  a  holding 
instrument  in  the  left  hand  and  such  a  plugger 
as  No.  5  or  No.  6,  Fig.  442,  in  the  right,  pack  the 
gold  into  the  angle  and  against  the  bevel  of  the 
margin  by  hand  pressure.  Place  over  this 
another  piece  of  semi-cohesive  gold  covering 
about  equally  the  axial,  lingual,  and  gingival 
walls,  and  pack  it  into  place,  but  do  not  en- 
tirely condense  it.  Next  apply  a  smaller  pellet 
of  annealed  gold  against  the  central  part  of  the 
last  piece,  and  with  a  small  point,  such  as  No.  1, 
thrust  the  annealed  gold  so  as  to  force  the 
semi-cohesive  gold  ahead  of  it  into  the  angle. 
A  few  additional  pieces  of  armealed  gold,  and 


381 


firm  pressure  with  a  small  point,  wOl  force  the 
semi-coliesive  gold  into  perfect  adaptation  and 
fill  the  angle  as  seen  in  the  central  incisor, 
Fig.  444.  To  proceed,  either  begin  separately  in 
the  labio-gingival  angle  or  build  along  the  axio- 
gingival  angle  until  the  labial  wall  is  reached. 
In  either  case  lay  semi-cohesive  gold  upon  the 
walls  and  force  cohesive  hito  it.  Fig.  444  sliows 
a  separate  start  made  in  tlie  labio-gingival  angle. 
Next  place  semi-cohesive  gold  uixni  all  un- 
covered surface  of  the  gingival  wall,  letting  it 
buncli  against  the  axial  wall  and  fully  cover  the 
bevelled  margin,  but  not  overlap  nnich  the 
condensed  gold  in  the  angles ;  pack  with  a  large 
])oint.  Upon  this  place  cohesive  gold,  so  that 
its  edges  will  weld  to  the  gold  in  the  angles. 
\Vith  hand  pressure  or  mallet  the  whole  may 
now  be  condensed,  and  cohesive  gold  added 
until  the  filling  is  firmly  locked  in  the  cavity. 
(See  lateral  incisor.  Fig.  444.) 

In  building  keep  the  gold  at  the  walls  and 
angles  in  advance,  and  in  condensing  always 
step  the  plugger  from  the  central  part  of  tlie 
filling  towards  the  walls.  After  the  gold  is 
firmly  locked  in  the  cavity,  make  .sure  liiat  the 
gingival  margin  is  filled  and  condensed  Hush 
witii  the  enamel  before  the  view  of  it  or  the 
approach  to  it  is  obstructed.  Tlie  same  care  is 
to  be  exercised  with  the  lingual  and,  later,  the 
labial  margins.  The  toe  of  tlu>  foot-plugger 
will  be  found  necessary  to  pack  and  sliape  tlie 
gold  at  the  gingival  margin  in  beginning  the 
contour.  In  such  cavities  as  these,  semi- 
cohesive    gold    in    small    pellets    may    be    used 


to  make  some  edges  of  the  fresh  piece  «eld  so 
that  it  will  not  curl  up  when  the  condenser  is 
applied  to  the  middle.  Sucii  a  condenser  as 
No.  7  is  excellent  in  building  contour,  wliiie  a 
form  like  No.  5  has  an  advantage  along  walls 
or  margins. 

The  direction  of  f(nve  in  condensing  gold 
should  mostly  be  nearly,  but  not  tiuite,  parallel 
with  the  long  axis  of  the  tooth.  Force  should 
always  be  directed  so  as  to  drive  the  gold  into 
the  cavity,  and  no  force  should  at  any  time  be 


Fig.  -4  44.  : 

against  the  walls  and  in  the  angles,  while 
annealed  or  fully  cohesive  gold  fori'ns  the  main 
body  of  the  tilling.  In  all  cases  the  cohesive 
gold  should  be  tlirust  firmly  into  the  semi- 
cohesive  with  small  pluggers  where  an  angle 
or  an  undercut  is  to  be  filled.  In  building 
contour  larger  pieces  of  gold  may  l)e  used  than 
are  permissible  elsewhere.  Such  an  instrument 
as  No.  8,  or  the  Varney  foot-plugger,  is  con- 
venient to  pack  or  mould  frcsii  pieces  to  the 
form  desired.     Enough  pressure  should  be  used 


used  tending  to  loosen  or  move  the  filling  from 
the  cavity.  This  should  be  especially  borne  in 
mind  when  malleting  upon  the  periphery  of  a 
contour,  where  a  blow  in  the  wrong  direction, 
though  unnoticed  at  the  tinu",  will  move  the 
filling,  causing  it  to  leak  and  impart  a  stained 
appearance  to  the  tootii  afterwards.  Huilding 
along  the  lingual  wall  should  be  kept  in  advance, 
as  indicated  in  the  lateral.  Fig.  445.  When  tiio 
incisal  undercut  is  reached,  the  small  right-angle 
for  the  lateral,  or  the  No.  2  point  for  the  central, 
will  be  suitable.  Small  jiellets  of  semi-cohesive 
gold  followed  by  small  pellets  of  coiiesive  should 
be  forced  in  the  lingual  direction  to  wedge 
the  gold  in  the  cavity  and  ct)nipletely  till  the 
retentive  undercut.  The  last  i)art  of  tiu'  cavity 
to  be  filled  is  indicated  in  the  central,  Fig.  445. 
[Previous  to  this  stage  the  incisal  )indere\it  is 
entirely  filled,  the  filling  being  tinis  tinally 
locked,  and  a  cohesive  surface  being  left  to 
receive  further  additions  of  gold  to  conipleto 
the  contour.  By  this  ])rocedure  good  oppor- 
tunity is  secured  to  build  the  contact  ]ioiat  and 
the  remainder  of  the  lingual  and  incisal  margins 
and  finish  t  he  work  when'  there  is  no  obstrui^t  ion. 
When  the  filling  is  thought  to  be  conipletcly 
built,  the  nuirgins  should  1h^  examined.  Any 
soft  or  unfilled  spots  should  receive  a  suital)ly 
small  pellet  of  well-annealed  gold  by  hand 
pressure,  so  that  the  filling  nuiy  be  finished 
without  any  pit  [!('«)]. 

Procedure  in  cavities  that  arc  much  extended 
lingually  while  the  labial  enamel  and  the  incisal 
angle  are  intact  and  sound  will  vary  from  the 


382 


foregoing.  Lingual  approach,  hand  pressure, 
and  proportionally  more  non-cohesive  gold  in 
larger  pieces,  will  be  used,  anchorage  being 
obtained  bet^¥een  opposing  walls  of  retentive 
form ;  cohesive  gold  will  be  added  only  to  form 


the  contour,  contact  point,  and  surface  exposed 
to  attrition. 

Finishing. — Restoration  of  contour  and  con- 
tact point  should  be  kept  constantly  in  mind 
during  the  preparation  of  the  cavity,  the  inser- 
tion of  the  gold,  and  the  finishing  of  approximal 
surfaces  (2). 

The  cavity  being  filled,  and  the  proper  contour 
built,  the  first  part  of  finishing  should  be  to 
burnish  the  whole  surface.  Beginning  with  a 
flat  burnisher  (see  No.  3,  Fig.  446)  at  the  contact 
point,  move  the  instrument  towards  and  over 
the  margins  in  all  directions,  except  at  the 
gingival  margin,  where,  to  avoid  injury  of  the 
gum,  the  burnisher  may  be  drawn  labially  at 
one  side  and  lingually  at  the  other;  No.  2  is  a 
form  of  burnisher  convenient  for  labial  or 
lingual  margins.  The  advantages  of  burnishing 
are  the  complete  condensation  of  the  surface  and 
the  tendency  to  fill  slight  pits  left  by  pluggers, 
and  also  the  final  and  complete  closure  effected 
between  the  gold  and  the  enamel  margins. 

Any  considerable  excess  of  gold  overlying  the 
enamel  after  burnishing  may  be  cut  away  at  the 
gingival  margin  with  small  safety  back  files 
{see  Nos.  6  and  7,  Fig.  446),  which  should  be 
operated  only  in  a  labio-lingual  direction  for 


the  safety  of  the  gum.  Excess  along  the  labial 
or  the  lingual  margin  may  be  most  satisfactorily 
cut  away  by  suitable  knives  or  draw-cut  scalers 
used  always  towards  the  enamel  and  never  in 
the  opposite  direction. 

Emery-paper  discs  of  small  diameter  and 
lubricated  liberally  with  vaseline  may  next  be 
used  to  dress  the  labial  and  lingual  margins. 
If  separation  is  sufficient,  |  inch  paper  discs 
may  be  used  to  dress  the  approximal  surface. 
In  doing  this  much  care  is  necessary  to  avoid 
undue  cutting  of  the  contact  point.  A  little 
pressure,  as  from  finger-ends  or  a  burnisher  upon 
the  back  of  the  disc  at  its  edge,  will  make  it  cut 
more  rapidly  the  part  against  which  the  pressure 
is  applied.  Such  pressure  is  usefully  introduced 
in  dressing  the  approximal  surface  at  or  near 
the  gingival  margin  with  the  edge  of  a  wide  disc 
not  allowed  to  cut  the  contact  point.  Margins 
extending  to  the  lingual  fossa  are  dressed  by 
application  of  a  ball  burnisher  to  the  back 
of  a  small  thin  disc  near  its  rim,  so  as  to  force 
the  grit  side  to  the  form  of  the  fossa  while  the 
disc  revolves.  In  most  cases  the  disc  should  be 
mounted  with  its  grit  side  towards  the  hand- 
piece. Vaseline  minimizes  frictional  heat,  and 
also  the  tendency  of  the  disc  to  catch  and  wmd 
the  rubber-dam.  A  thin  finishing  strip  may  be 
used  upon  the  gingival  portion ;  this  strip  should 
be  so  narrow  as  to  ^^•ork  witlaout  cutting  the 
contact  point,  and  should  be  well  vaselined ; 
care  is  necessary  in  the  use  of  strips  to  avoid 
injury  of  the  gum  or  the  pericementum.  Cuttle- 
fish or  crocus  discs  may  be  used,  and  finally  a 
thin  strip  charged  with  fine  grit  may  be  drawn 
a  few  times  over  the  whole  filling,  provided  no 
pressure  of  the  adjacent  tooth  is  allowed  upon 
the  back  of  the  strip  at  the  contact  point,  to  give 


Fig.  447. 

a  satisfactory  surface  to  the  whole  of  an  incisor 
filling  [l(p)]. 

When  removing  the  rubber-dam,  be  sure  to 
remove  all  shreds  of  rubber  or  ligature,  or  any 
foreign  matter,  that  may  have  found  its  way 
under  the  gum  margin  during  the  operation. 
Vigorous  streams  of  water  from  a  syringe  serve 


383 


well  for  the  removal  of  grit  used  in  finishing,  or 
other  matter  that  should  not  be  allowed  to 
remain  where  it  may  cause  injury  to  the  sur- 
rounding parts. 

Fig.  447  is  an  approximal  view  of  the  finished 
fillings.  Figs.  448  and  449  are  labial  views  of 
the  filled  teeth  in  situ.  Fig.  450  is  a  lingual 
view  of  the  filled  teeth  in  situ. 

Note  in  Figs.  448, 449,  and  450,  that  contact  of 
the  filled  teeth  occurs  upon  the  fUlings  only ; 
cavity  outlines  should  in  all  cases  be  managed  so 
as  not  to  allow  contact  of  the  teeth  to  occur  at  or 
near  the  joint  between  filling  and  enamel.     The 


Fig.  448. 

medial  filling  in  the  central.  Fig.  450,  shows 
extension  to  the  lingual  surface  for  the  removal 
of  tissue  too  much  damaged  by  caries  to  remain. 
The  lingual  and  gingival  extension  seen  in  the 
other  fillings  in  these  teeth  is  ordinarilv  sufficient, 


Fig.  449. 

and  need  not  be  exceeded  except  in  cases  of 
extreme  susceptibOity  or  for  the  removal  of 
tissue  unfit  to  remain.  The  labial  extension 
seen  in  Figs.  448  and  449  is  the  maximum  to  be 
used  for  prophylactic  reasons.  In  extreme  cases 
indicated  by  ext;nsion  of  caries  of  the  enamel 


along  the  gum  line  the  cavity  should  be  extended 
to  include  all  carious  enamel. 

Fig.  451  shows  the  relation  of  the  cavity  out- 
line to  the  gum  margin,  and  the  appearance  of 
fillings  thus  extended  labially.  Note  that  the 
free  margin  of  gum  covers  the  gingival  margin 


Fig.   45'J. 

of  the  filling ;  while  the  joint  is  thus  covered 
gingival  recurrence  of  caries  will  not  take  place. 
The  maintenance  of  the  inter-proximal  space 
and  of  the  health  of  the  tissues  occupying  it  are 
therefore  of  the  first  importance  in  the  preven- 
tion of  both  caries  and  pyorrhoea  alveolaris. 


Fig.   451. 

The  student  is  advised  to  note  well  tlie  form 
of  the  gingival  lines  upon  the  incisors  as  seen 
in  these  figures,  so  that  in  the  application  of 
ligatures,  finishing  instruments,  etc.,  he  may 
the  better  guard  against  violence  to  the  peri- 
cementum, which,  if  wounded  or  separated  from 
the  cementum,is  likely  to  remain  in  a  permanently 
diseased  condition  (2). 

Class  2. — Pit  and  Fissure  Cavities 

Typical  examples  of  the  smaller  pit  and  fissure 
cavities  prepared  for  filling  are  seen  in  Fig.  452. 
The  filling  of  these  ca\'ities  with  foil  is  a  com- 
paratively simple  operation.  The  end  of  a  roll 
of  very  slightly  cohesive  foil  is  introduced  and 


384 


with  thrusts  of  such  a  phigger  as  Nos.  5  or  6, 
Fig.  442,  packed  until  the  cavity  is  one-half  or 
two-thirds  filled.  Into  the  gold  thus  packed 
cohesive  gold  is  thrust  with  a  small  point  and 
by  hand  pressure  until  the  whole  is  solid  and 
the  cavity  has  a  firm  grip  of  it.  By  mallet  or 
hand  pressure  the  remainder  of  the  cavity  is 
filled  with  cohesive  gold.  No  considerable  ex- 
cess of  gold  should  be  allowed  to  extend  over 
the  uncut  enamel ;  by  the  addition  of  small 
pieces  at  the  last  the  desired  fullness  may  be 
obtained  without  excess.  Serrations  at  the 
edges  of  the  plugger  faces  should 'not  be  sharp, 


Fig.   452. 

but  rather  smooth  or  rounded,  so  that  in  sliding 
upon  the  inclines  leading  into  the  cavity  they 
will  not  catch  or  injure  the  enamel. 

In  the  larger  occlusal  cavities  of  Class  2  in 
molars  non-cohesive  gold  may  be  used  for  the 
greater  part  of  the  filling.  Cylinders  long  enough 
to  reach  the  cavity  margins  are  placed  on  end 
and  forced  to  the  walls.  Wlien  the  greater  part 
of  the  cavity  is  thus  filled,  the  walls  and  floor 
being  covered,  a  pellet  of  cohesive  gold  is  fii-mly 
thrust  into  the  mass  at  the  centre.  Cohesive 
gold  is  added  in  an  outward  direction  until  the 


Fig.  453. 

non-cohesive  is  forced  solid  against  the  walls 
and  margins  and  partly  covered  by  cohesive 
gold.  The  welded  surface  ^vill  stand  attrition 
better  than  will  non-cohesive  gold,  while  the 
adaptability  and  rapid  filling  qualities  of  the 
latter  are  fully  utilized  (4)  (7).  To  finish  this 
kind  of  filling  a  hand  burnisher  with  rounded 
point  such  as  No.  1,  Fig.  446,  may  be  used,  so  as 
to  leave  a  good  finish  with  no  occasion  for  cutting 
or  further  polish.  A  straight  instrument  with 
a  smooth  and  somewhat  flattened  end  may  often 
be  used  with  mallet  blows  to  condense  and 
smooth  tlie  surface  of  this  kind  of  filling.  Any 
excess  of  gold  overlying  enamel  in  grooves  or 


depressions  can  be  cut  away  with  a  discoid 
excavator  or  such  an  instrument  as  No.  5, 
Fig.  446,  and  complete  finish  made  by  burnish- 
ing. Fig.  453  shows  the  cavities  filled,  and 
finished  by  burnishing. 

Treatment  of  buccal  pits  in  molars,  or  lingual 
pits  in  lateral  incisors,  is  essentially  the  same  as 
in  the  examples  illustrated. 

Class  3. — Labial  and  Buccal  Cavities 

Fillings  in  these  cavities  are  exposed  to  little 
friction  or  wear,  and  to  no  stress,  in  mastication ; 
therefore  strength  and  hardness  in  the  material 
used  are  not  essential.  The  situation  at  the 
gum  margm,  where  these  cavities  begin,  is 
unfavourable  for  easy  or  harmless  application 
of  the  rubber-dam ;  and,  except  in  the  upper 
incisors  and  canines,  quite  as  unfavourable  for 
the  safe  or  harmless  use  of  the  usual  means  of 
finishing  gold.  The  colour  of  gold  is  sometimes, 
and  its  conducting  properties  are  always, 
objectionable  in  these  cases.  The  pulp  is 
separated  from  the  filling  by  a  very  thin  body 
of  dentine  at  the  neck  of  the  tooth.  Considering 
the  difficulties  and  the  liability  of  adjacent  parts 
to  injury,  gold  foil  can  hardly  be  recommended 
as  generally  suitable  to  such  cavities,  especially 
in  the  lower  teeth.  Inlays,  gutta-percha, 
amalgam,  and  oxy-phosphate  of  copper,  afford 
alternatives  where  such  obstacles  are  promi- 
nently in  the  way  of  foil-work. 

Labial  cavities  in  upper  incisors  or  canines 
may,  however,  be  filled  with  foil  without  using 
the  rubber-dam.  It  has  been  found  quite 
practicable  to  work  foil  in  these  cases  without 
the  rubber  for  patients  whose  control  of  lips  and 
tongue  is  good,  and  from  whose  gums  there  is 
no  abnormal  exudation. 

Having  the  cavity  prepared,  wash  the  moiith 
with  warm  water,  dry  the  gum  and  lip,  place  a 
cotton-wool  roll  under  the  lip,  and  the  edge  of 
a  napkin  below  the  upper  teeth.  Dry  the  cavity 
and  gum  margin  with  alcohol  and  warm  air. 
Begin  at  once  with  a  large  pellet  or  cylinder  of 
very  slightly  cohesive,  or  non-cohesive,  gold 
against  the  gingival  wall.  Let  this  piece  pro- 
trude a  little  from  the  cavity,  even  if  it  is 
against  the  gum,  to  ensure  complete  filling  of 
the  cavity  at  the  gingival  margin.  Use  a 
plugger  in  each  hand  and  rapidly  pack  the 
semi-cohesive  gold,  adding  only  enough  cohesive 
gold  to  bind  or  toughen  the  filling  and  render  it 
stable  for  finishing.  A  cavity  may  thus  be  well 
filled  in  a  few  niinutes,  or  at  least  before  there 
is  any  oozing  of  moisture  to  prevent  the  ^\•orking 
of  gold.  When  all  the  gold  is  in  moisture  can 
do  no  harm ;  it  may  be  wiped  away  while  the 
filling  is  being  finished. 

Having  the  contour  restored,  burnish  the 
whole  surface,  remove  any  excess  at  the  gingival 
margin  with  files  or  points  of  knives,  and  burnish 


385 


smooth  all  gold  covered  by  gum.  The  rest  of 
the  filling  may  be  finished  with  the  edges  of 
small  paper  discs  mounted  on  a  small  neat 
mandrel  with  thin  screw-head ;  thorough  control 
of  the  disc  should  be  maintained,  but  no  attempt 
made  to  operate  a  paper  disc  under  the  gum. 

W.  C.  G. 

BIBLIOGRAPHY 

(1)  Black,     G.     V.     Operative    Dentistry,    Vol.     II: 

(a)  Cavity  Preparation,  pp.  105  ei  seq.  (6)  Re- 
tention Form,  pp.  113,  126,  182,  208.  (c) 
Modification  of  Alloys,  p.  312.  (d)  Inlays, 
pp.  330  et  seq.  (e)  Filling  Materials,  p.  224. 
(/)  Injuries  by  Use  of  Clamps,  p.  51.  [g)  Liga- 
tures, p.  86.  {h)  Nature  of  Blows,  p.  237. 
(i)  Application  of  Force,  p.  251.  (/)  Plugger 
Points,  pp.  2.54  ct  seq.  {k)  Forms  of  Gold, 
p.  227.  {!)  Preparation  of  Foil,  p.  249.  (m) 
Filling  Incisors  and  Canines,  p.  282.  (n)  Cavities 
in  Approximal  Surfaces  in  Premolars  and 
Molars,  pp.  143  et  seq.  (o)  Filling  Approximal 
Cavities  in  Premolars  and  Molars,  pp.  265  et  seq. 
(p)  Finishing  Gold  Fillings,  pp.  291  et  seq. 

(2)  Black,  G.  V.     The  Contact  Point  and   its  Func- 

tion considered  with  Reference  to  Caries  and 
its  Treatment.  Dental  Review,  1909,  pp.  595- 
663. 

(3)  Clack,   W.    R.     Gold   Fillings.     Dental   Cosmos, 

1909,  Vol.  LI,  pp.   1274-1304. 

(4)  Clapp,  D.  M.     Various  Kinds  of  Gold  in  Combina- 

tion. Kjrk^s  Operative  Dentistry,  3rd  ed., 
p.  345. 

(5)  COE,  Ika  J.     New  Feature  in  Retention  of  Gold 

FiUings.  Dental  Cosmos,  1906,  Vol.  XLVIII, 
p.  563. 

(6)  Darby,   E.   T.     Gold   and   Tin   Fillings.     Kirk's 

Operative  Dentistry,  3rd  ed.,  p.  227. 

(7)  Dunning,    W.    B.      Manipulation    of    Non-cohe- 

sive Gold.  Dental  Cosmos,  1906,  Vol.  XLVIII, 
p.  558. 


(8)  Enomoto,     Sekichi.      Annealing    Gold.     Dental 

Cosmos,  1905,  Vol.  XLVII,  p.  233. 

(9)  Geayston,  VV.  C.    Gold  Filling.    Brit.  Dent.  Jour., 

1909,  Vol.  XXIX,  p.  241. 

(10)  Gbayston,  W.  C.     Gold  Fillings  (Tests).     Trans. 

Odont.  Soc,  1901-2,  p.  47. 

(11)  Johnson,  C.  N.     Principles  and  Practice  of  Filling 

Teeth.  3rd  ed.  (a)  Crystal  Golds,  pp.  174-5. 
(6)  Experiments  with  Various   Mallets,   p.    178. 

(c)  Automatic   and  Rapid  Mallets,  pp.    182-3. 

(d)  Hand  Pressure,  pp.  185  et  seq.  (e)  Protecting 
Periodontal  Membrane,  p.  187.  (/)  Matrices, 
pp.  201  et  seq.  (gf)  Finishing  Filhngs,  p.  214.  (h) 
Manipulation  of  Tin  and  Gold,  pp.  228  et  seq. 
(i)  Manipulation  of  Amalgam,  pp.  232  et  seq. 
(/)  Manipulation  of  Gutta-percha,  pp.  239  et 
seq. 

(12)  LiTCH,  Wilbur  F.     American  System  of  Dentistry, 

Vol.  II.  (a)  General  Principles  concerning 
Packing  of  Gold,  pp.  107-123.  (6)  Hprbst 
Method  of  Gold  Filling,  pp.   207-217. 

(13)  Matheson,     L.     Gold     Fillings.     Trans.     Odont. 

Soc,  1903-4,  p.  220. 

(14)  Noel,   L.    G.     Methods   of    combining   Cohesive 

with  Non-cohesive  Gold  or  with  Tin,  or  Tin 
with  Non-cohesive  Gold.  Dental  Cosmos,  1908, 
Vol.  L,  pp.  320-6. 

(15)  Ottolengui,     R.     Methods     of     Filling     Teeth. 

(a)  Gold  as  a  Filling  Material,  pp.  69-77. 
(6)  Uses  of  Heavy  Gold,  pp.  77-81.  (c)  Lining 
Cavity  with  Oxy-phosphate,  pp.  82-3.  (d)  Con- 
densing Gold,  pp.  85-9.  (e)  Preparing  Cavities 
for  Gold,  pp.  114-184.  (/)  Finishing  Gold 
Filling,  pp.   187-9. 

(16)  Owre,   Alfred.     Johnson's   Operative   Dentistry. 

(a)  Gold  Filling,  p.  225.      (6)  Tin  Filling,  p.  245. 

(17)  Parfitt,     J.    B.     Mechanical    Principles     (Gold 

Fillings).      Trans.  Odont.  Soc.,  1906-7,  p.  34. 

(18)  Sachs,   Prof.   Wilhelm.     Adjusting  Matrix   for 

Approximal  Cavities  in  Molars  and  Premolars. 
Dental  Cosmos,  1908,  Vol.  L,  p.  531. 

(19)  Wedelstaedt,   E.    K.     Methods  and   Principles 

of  Packing  Gold.  Dental  Cosmos,  1905,  Vol. 
XLVII,  p.  985. 


13 


CHAPTER  XXIII 

PLASTIC    FILLINGS 


Easily  moulded  filling  -  materials,  which 
undergo  a  process  of  self-hardening,  are 
known  as  "  Plastics  ". 

Great  as  are  the  advantages  pertaining  to 
these  two  properties  something  further  is 
demanded  of  the  ideal  fillmg.  Thus,  it  should 
resemble  m  colour  and  appearance  the  adjacent 
tooth  tissue ;  harden  fairly  rapidly ;  maintam 
its  form,  i.  e.  neither  contract,  expand,  nor 
warp,  and  be  insoluble  in  the  oral  fluids ;  be 
strong  enough  to  stand  the  mechanical  stress 
of  mastication  without  fracturing  or  becoming 
defaced  ;  be  capable  of  receiving  and  maintaming 
a  high  polish ;  and  exert  no  mjurious  effects 
on  the  hard  or  soft  dental  structures. 

AU  these  desu'able  qualities  are  not  to  be 
met  \\  ith  in  any  single  filling ;  the  plastics,  how- 
ever, combme  many  of  them,  and  as  will  be 
shown,  some  have  jjroved  the  most  generally 
useful  of  all  the  fillings  at  present  in  use. 

Plastic  fillings  may  be  divided  into  three 
mam  classes — 

1.  Dental    Amalyams — metallic    alloys    con- 

taming  mercury. 

2.  Osteo-plastic      Cements — inorganic      com- 

pounds  resulting   from    the    union   of 
a  powder  with  a  liquid. 

3.  Compounds — largely    organic,    containing 

gutta-percha. 

1.  DENTAL  AMALGAMS 

In  its  widest  sense  an  amalgam  is  an  alloy 
of  one  or  more  metals  with  mercury.  A 
dental  amalgam  is  such  an  alloy,  ui  which, 
however,  the  mercury  is  present  as  one  of  the 
chief  constituents.  The  other  metals  usually 
employed  are  silver,  tin,  copper,  gold,  zinc, 
platinum,  palladium,  and  bismuth. 

Of  these,  copper  is  sometimes  used  alone,  as 
is  also  palladium,  to  form  simple  binary  amal- 
gams, but  the  ternary  alloy  of  mercury,  silver, 
and  tin,  occasionally  modified  by  the  addition 
of  small  amounts  of  certam  other  metals,  has  i 
proved  the  most  reliable  in  practice.  1 

Amalgamation. — Mercury     is    in    several    re-   I 
spects  a  remarkable  metal ;  fluid  at  ordinary   I 
temperatures,  it  volatilizes  at  360°  C,  and  will 
combine  to  some  extent,  even  in  the  cold,  with 
nearly  all  the  other  metals.      Amalgamation  is 
facilitated  and  rendered  more  thorough  by  heat,   ; 

386 


and  by  the  other  metals  being  in  a  fine  state 
of  division.  In  the  case  of  copper  and  palla- 
dium, ^precipitates  of  the  metals  obtained  from 
solutions  of  their  salts  are  used ;  with  ternary 
and  other  alloys,  the  metals  other  than  the 
mercury  are  alloyed  fu'st  by  fusion,  and  then 
reduced  to  a  fine  state,  by  filing,  drilling,  or 
turning  the  mgot.  The  production  of  this 
primary  alloy  is  a  matter  of  some  importance. 
Wlien  the  meltmg  is  conducted  in  an  ordinary 
crucible  oxidation  of  some  of  the  base  metals 
is  very  liable  to  occur,  with  the  result  that  the 
composition  of  the  alloy  is  varied ;  hence  it  is 
best  to  employ  (4,  f»-  307)  a  closed  electric 
crucible  and  fuse  the  metals  together  under 
hydrogen.  Further,  it  is  very  difficult  to 
obtam  an  ingot  that  is  perfectly  homogeneous, 
one  m  which  the  metals  are  evenly  alloyed 
throughout  the  mass.  Two  pomts  only,  liavmg 
a  bearmg  on  this  matter,  may  be  mentioned 
here.  When  two  metals  of  differing  densities 
are  melted  and  poured  together  into  a  vessel, 
preferably  higher  than  it  is  wide,  the  metal  with 
the  greater  specific  gravity  tends  to  collect  at  the 
bottom,  and  the  lighter  metal  at  the  top,  but 
it  ^\ill  be  found  on  analysis  that  the  separation 
is  not  complete — some  of  the  heavier  metal 
has  passed  up  into  the  lighter  metal,  whilst  a 
portion  of  the  lighter  metal  has  combined  with 
the  heavier  metal  below. 

Again,  by  means  of  the  readings  of  a  pyro- 
meter it  is  possible  to  construct  a  curve  illustrat- 
ing the  behaviour  of  a  cooling  mass  of  metal  or 
aUoy.  When  a  single  metal  cools,  the  coolmg 
curve  becomes  practically  horizontal  at  the 
point  of  the  metal's  solidification.  But  in 
tlie  case  of  an  alloy  several  interruptions  of  the 
curve  may  be  noticed ;  these  breaks  correspond 
with  the  formation  of  crystals  of  a  definite 
composition,  and  may  be  observed  after  the 
mass  has  solidified.  It  has  been  shown  by 
Black  that  an  amalgam  made  from  filings  cut 
from  previously  prepared  alloy  possesses  physical 
properties  different  from  those  of  an  amalgam 
made  from  the  precipitates  of  the  same  metals, 
the  proportions  of  the  metals  being  the  same 
in  each  case  (4,  p.  307) ;  so  that  it  is  possible 
that  the  manner  in  wliich  the  primary  alloy 
is  cooled,  quickly  or  slowly,  may  have  some 
influence  on  the  properties  of  the  resultant 
amalgam. 


387 


For  the  supj)ly  of  these  alloys  the  dentist 
is  entii'ely  iii  the  hands  of  the  manufacturers, 
and  it  is  to  be  feared  that  many  of  them  are 
prepared  in  a  wholly  empirical  manner,  with 
no  regard  to  their  perfect  homogeneity. 

When  the  filhigs  or  turnmgs  from  a  previously 
prepared  alloy  are  brought  into  intimate  contact 
with  a  sufficiency  of  mercury,  either  by  tritura- 
tion with  pestle  and  mortar,  by  shakuig  the 
filuigs  together  m  a  test  tube,  or  by  simply 
nibbing  them  together  in  the  palm  of  the  hand, 
the  other  metals  go  into  solution  with  the 
mercury  very  much  in  the  same  manner  as  do 
metals  when  fused  in  a  crucible,  a  soft  plastic 
mass  being  formed.  Sooner  or  later,  but  usually 
in  a  few  mmutes,  tlie  time  varymg  with  the 
composition  and  treatment  of  the  primary 
(silver-tin)  alloy,  and  the  amount  of  mercury, 
a  process  of  crystallization  ensues,  and  the  mass 
becomes  harder,  feeling  crystalline  \^'hen  rubbed 
between  the  fingers,  and  finally  sets.  In  this 
way  is  formed  a  solid  metallic  alloy,  which  may 
be  a  chemical  compound,  or  series  of  com- 
pounds, composed  of  mercury  and  the  other 
metals  in  the  alloy,  crystallized,  and  dissolved 
in  the  excess  of  mercury  present. 

There  is,  and  always  must  be,  some  excess 
of  mercury  present  in  the  original  mix,  over 
and  above  that  requu-ed  to  satisfy  the  chemical 
affinities  of  the  other  metals,  in  order  that  the 
alloy  may  be  rendered  sufficiently  plastic  to 
be  workable.  This  excess  is  usually  partly 
removed  by  squeezing  it  out,  through  chamois 
leather  or  linen,  before  packing  the  amalgam 
into  the  tooth  cavity ;  and  as  will  be  seen  later, 
much  care  is  taken  to  remove,  as  far  as  possible, 
the  remainder  of  the  excess  during  the  insertion 
of  tlie  filluig.  It  is  jjossible  that  the  variations 
in  the  amount  of  mercury  used,  over  and  above 
that  which  is  necessary,  and  the  alteration  in 
the  constitution  of  the  alio  •,  consequent  upon 
the  extraction  of  small  qua  titles  of  the  other 
metals  with  the  expressed  mercury,  account 
in  some  degree  for  the  differii  "■  results  achieved 
with  amalgam  fillings. 

It  has  already  been  mention  'd  that  amalgam- 
ation is  facilitated  by  heat,  uid  Fenchel  has 
pointed  out  that  an  alloy  \\ith  a  low  melting- 
point  will  combine  more  readily  and  more 
completely  with  mercury  than  one  with  a  high 
melting-point ;  further,  that  as  a  result  of  the 
complete  solution  of  the  alloy  in  the  mercury, 
a  true  homogeneous  amalgam  may  be  expected 
by  recrystallization  out  of  a  perfect  solution, 
thus  obviating  the  formation  of  masses  of 
amalgam  uniting  imamalgamated  crystals  of 
the  primary  alloy ;  and  he  advocates  the  use 
of  a  primary  alloy  compo.sed  of  silver  48,  tin 
52,  which  melts  at  470°  C.  (14). 

The  majority  of  alloys  in  use  to-day  possess 
a  nmch  larger  content  of  silver.     These  high- 


(jrmh  alloys,  as  they  are  called,  set  rapidly, 
particularly  so  if  the  filings  are  coarse  and  are 
used  when  freshly  cut.  There  is  a  possible 
advantage  to  be  derived  from  rapid  setting, 
inasmuch  as  the  amalgam  mass  is  under  the 
control  of  the  operator  and  may  be  condensed 
during  a  critical  jseriod,  when  many  changes 
in  form  are  liable  to  occur;  further,  it  is  less 
likely  to  be  defaced  by  use  before  it  has 
hardened. 

Alterations  in  Form. — Just  as  other  alloys 
undergo  changes  in  density  at  the  time  of 
solidification,  so  amalgam  alloys  exhibit  changes 
of  form  whUst  hardening;  and  although  it  is 
true  that  these  changes  are  very  marked  at 
and  about  the  period  of  setting,  yet  in  some 
instances  they  continue  to  occur  for  some 
considerable  time  after  the  mass  has  apparently 
fully  hardened.  Thus  a  dental  amalgam  may 
either  contract,  exj)and,  or  warp.  Many  alloys 
contract  at  first,  but  subsequently  expand  and 
recover  their  original  density,  or  may  go  be- 
yond it ;  a  few  expand  at  first  and  then  contract ; 
others  expand  or  contiact  only. 

Black  has  shown  that  expansion  and  con- 
traction are  mainly  due  to  the  composition  of 
the  primary  alloy,  and  partly  to  its  method 
of  preparation  and  the  amount  of  mercury  used. 
Speaking  generally,  in  a  ternary  alloy  of  mer- 
cury, silver,  and  tin,  the  silver  promotes  ex- 
pansion, whilst  the  tin  tends  to  induce  contrac- 
tion. It  has  been  found  by  experiment  that 
with  an  alloy  composed  of  silver,  65  parts, 
and  tin,  35  parts,  mixed  with  52  per  cent 
of  mercury,  the  tendency  towards  expansion 
and  contraction  on  the  part  of  these  two 
metals  is  approximately  neutralized,  and  that 
such  an  alloy  yields  an  amalgam  that  is  practi- 
cally unalterable.  This  result,  however,  is  only 
achieved  when  the  amalgam  is  made  with 
filings  that  are  freshly  cut,  or  with  shavings 
newly  turned  (4,  p.  308).  Fresh-cut  alloys 
containing  over  65  jjer  cent  of  silver  and  less 
than  35  jJcr  cent  of  tin,  as  a  general  rule,  form 
amalgams  that  expand,  the  expansion  being 
very  marked  when  the  silver  exceeds  70  per 
cent ;  whilst  those  containing  less  than  65  per 
cent  of  silver  and  more  than  35  per  cent  of 
tin  contract. 

Tomes  has  shown  that  there  is  a  minimum 
of  shrinkage  resulting  from  the  use  of  pieces 
of  old  silver-tin  amalgam,  which  have  been 
heated  and  softened  in  the  same  manner  as 
that  adopted  when  working  copper  amalgam 
(23).  Silver -tin  amalgam,  however,  when  so 
used,  sets  so  rapidly  that  it  is  almost  impossible 
to  pack  it  into  any  but  the  simplest  and  most 
accessible  cavities.  The  same  observer  has 
also  found  that  shrinkage  may  be  partly  con- 
trolled by  inserting  hard  metallic  bodies,  such 
as  pieces  of  already  hardened  amalgam,  small 


388 


iron  rinrrs,  etc.,  into  the  amalgam  mass  whUe 
it  is  still  soft. 

The  form  of  shrinkage  or  of  expansion  de- 
pends somewhat  on  the  shape  of  the  ping,  and, 
if  it  is  packed  into  a  cavity,  on  the  shajoe  and 
character  of  that  cavity.  Thus  amalgam  packed 
into  a  simple  mould,  slightly  undercut,  with 
approximately  straight  walls,  and  a  flat  base, 
will  exhibit  shrinkage  after  the  form  shown  in 
Fig.  454.  On  the  other  hand,  should  the  alloy 
used  be  one  that  expands,  the  expansion  will 
take  place  in  the  dhection  of  least  resistance, 
and  hence  it  wUl  rise  from  the  of)en  end  of  the 
mould ;  further,  it  will  experience  some  resist- 
ance at  the  sides  of  the  mould,  and  wUl  as  a 
result  of  this  rise  more  easily  and  to  a  greater 
extent  in  the  centre,  very  much  in  the  same 
way  as  ice  forms  at  the  open  end  of  a  tube 
when  the  water  that  it  contains  is  frozen.     This 


Fig.  454. 

appearance  gave  rise  to  the  idea  that  there 
was  a  tendency  on  the  part  of  some  amalgams 
to  "  spheroid". 

The  Amount  and  Distribution  of  the  Mercury. 
With  an  unalterable  alloy,  such  as  one  composed 
of  sil\er,  65  per  cent,  and  tin,  35  per  cent, 
when  the  filings  are  used  freshly  cut,  variations 
in  the  amount  of  mercury  incorporated  with 
tliem  have  no  effect  upon  the  volume  of  the 
amalgam  made,  that  is  to  say,  upon  its  con- 
traction or  expansion ;  variation  in  the  amount 
of  mercury,  however,  seriously  affects  its  rigidity 
and  strength.  The  quantity  of  mercury  required 
to  f)roduce  the  strongest  plug  differs  with  the 
formula  and  method  of  preparation  of  the 
primary  alloy  ;  it  is  usually  bet\^een  30  per  cent 
and  60  per  cent.  Freshly  cut  and  finely  com- 
niiiuited  alloys,  and  also  those  that  contam  much 
silver  requue  a  large  amount  of  mercury. 

Alterations  in  the  quantity  of  mercury  used 
V  ith  alloys  that  have  a  greater  or  lesser  content 
of  silver  than  65  per  cent,  however,  increase 
the  contraction  and  expansion  resjaectively  of 
these  alloys,  and  these  changes  caimot  be 
controlled  by  the  percentage  of  mercury 
employed. 

It  is  of  the  utmost  importance  that  the 
mercury  should  be  evenly  distributed  through- 
out the  mass.  As  the  plug  hardens,  there  is 
apparently  a  tendency  for  the  excess  of  mercury 
in  what  may  l)e  termed  the  wetter  portion  to 
migrate  to  the  drier  portion,  and  this  spon- 
taneous equalization  of  the  distribution  of  the 


mercury  is  often  accompanied  by  some  warping 
or  twisting  of  the  plug  (lit). 

Changes  in  Form  due  to  Mechanical  Stress. — A 
mass  of  amalgam,  when  fuUy  set,  possesses  in 
some  curious  way  the  two  opposite  physical 
properties  of  brittleness  and  flow.  Thus,  when 
a  piece  of  amalgam  is  struck  a  smart  blow  with 
a  hammer,  or  subjected  to  very  great  pressure, 
it  win  fly  to  pieces ;  yet  it  Ls  almost  malleable 
when  the  j^ressure  is  limited  to  an  amount 
below  that  required  to  produce  fracture  (5). 
Further  its  malleability  is  of  a  distinctive  kind. 
When  a  cube  of  pure  gold  is  compressed,  it 
yields  to  an  extent  limited  by  the  amount  of 
the  pressure  to  which  it  is  subjected,  and  camiot 
be  made  to  yield  further  unless  the  pressure 
is  increased.  Many  dental  amalgams,  on  the 
other  hand,  will  yield  or  flow  under  pressure 
so  long  as  the  pressure  is  maintained,  no  matter 
whether  it  is  constant  or  intermittent,  and  that 
without  any  increase  m  the  amount  of  the 
stress  applied.  It  will  be  evident  that  this 
prof)erty  of  molecular  motion  under  stress  is 
one  of  extreme  importance  from  the  point  of 
view  of  the  stability  of  an  amalgam  filling.  For 
whilst  an  amalgam  may  be  sufficiently  strong 
to  withstand  the  strain  of  mastication  without 
fracturing,  its  strength  will  be  of  no  avail,  so 
far  as  its  tooth-saving  properties  are  concerned, 
if  it  is  liable  to  be  defaced,  and  to  flow  away 
from  the  cavity  margins.  The  tendency  to 
flow  is  at  zero  in  the  binary  amalgam  of  copper 
and  mercury ;  is  less  marked  in  those  silver-tin 
alloys  that  contain  from  two  per  cent  to  five 
per  cent  of  cof)i5er ;  and  also  in  those  amalgams 
that  are  made  from  freshly  cut  filings. 

The  flow  is  increased  by  using  an  excess  of 
mercury,  and  by  unevenness  in  its  distribution 
throughout  the  mass ;  it  is  also  greater  in 
amalgams  made  from  very  finely  comminuted 
filings  or  from  those  that  have  been  annealed. 
Increase  in  the  percentage  of  tin  increases  the 
flow,  as  does  also  the  addition  of  gold  to  a 
sUver-tin  alloy. 

The  following  table  from  Black  shows  some 
of  the  results  obtained  by  him,  the  percentage 
of  flow  being  that  per  hour,  \\ith  a  pressure  of 
60  lb. 


Silver 

60 

42-45 

70 


Tin 

40 

57-55 

30 


Percentage 
of  Mercury 

38-58 
39-05 
50 


Percentage 
of  Flow 

2-91 

9 

4-12 


Crushing  Stress. — It  is  very  rarely  that  an 
amalgam  filling,  when  once  fully  hardened,  frac- 
tures under  the  stress  of  mastication.  Before 
it  has  fully  set,  however,  it  passes  through  a 
stage  in  which  it  is  very  friable,  and  is  then 
easily  broken  if  bitten  upon.  Amalgams  made 
from   alloys   containing   a   high   percentage   of 


389 


silver  possess  a  good  crushing  stress,  but  it  is 
reduced  by  increasing  the  amount  of  tin,  by 
using  filmgs  that  have  been  freshly  cut,  and 
by  incorporating  too  much  or  too  little  mercury 
A^itli  the  mix.  The  addition  of  five  per  cent 
of  gold  to  a  silver-tin  alloy  slightly  raises  its 
crushuig  stress,  whilst  the  addition  of  a  similar 
amount  of  copper  raises  it  very  considerably. 
No  other  metal  appears  to  have  any  beneficial 
effect  in  this  respect.  A  cube  of  amalgam 
measurmg  '085  inch  will  withstand  a  pressure 
of  from  200  lb  to  400  lb  before  crushmg, 
varymg  of  course  with  the  composition  of  the 
alloy  and  the  methods  adopted  in  its  preparation. 
It  will  thus  be  seen  that  amalgam  fillings  usually 
possess  sufficient  strength  for  the  purposes 
required  of  them. 

The  Ageing  or  Annealing  of  Comminuted 
Amalgam  Alloys. — When  an  amalgam  is  mado 
with  filings  immediately  after  they  have  been 
cut,  an  alloy  is  produced  that  possesses  pro- 
perties differmg  from  those  possessed  by  an 
aUoy  made  from  the  same  batch  of  filings  some 
weeks  or  months  after  they  have  been  cut. 
Two  explanations  have  been  offered  to  account 
for  these  changes,  one  being  that  they  are  due 
to  the  surface  oxidation  of  the  filings,  and  the 
other  that  they  are  the  result  of  a  slow  process 
of  annealing,  \\hich  the  filings  undergo  when 
left  at  rest  in  a  moderately  warm  room.  It 
is  probable  that  the  second  of  these  two  ex- 
planations is  the  correct  one,  the  argument 
being  that  as  the  filings  come  off  from  the  file 
they  are  rendered  hard  and  harsh,  and  that  the 
displaced  molecules  of  the  alloy  subsequently 
readjust  themselves  (4,  p.  309) ;  thus  filings 
may  be  artificially  aged  by  annealing  them  as 
soon  as  they  are  cut,  and  it  has  been  found  by 
experiment  that  this  may  be  efficiently  accom- 
plished by  placing  the  filings  in  a  test  tube, 
and  the  latter  in  boiling  water  for  twenty 
minutes.  Tlie  following  table  shows  the  effects 
of  annealing  on  the  physical  and  working 
properties  of  the  same  alloy  (4,  p.  310) — 

Percentage  Flow     Crush- 
of           Shrink-  Expan-       per-         ing 

Silver  Tin   Mercury        age         siou  centage    Stress 

Fresh-cut  65     35       52  0        1-5  3-67      290 

Annealed    65     35        33        6-10         0  5  335 

Thus  it  wUl  be  seen  that  as  the  result  of 
annealing  less  mercury  is  required  to  make  a 
working  mi.x  ;  that  the  expansion  of  an  expand- 
ing alloy  is  reduced  ;  and  that  both  the  flow  and 
the  crushing  .stress  are  increased.  Further, 
the  setting  of  the  mass  is  delayed. 

The  effects  of  annealing  are  proportional  to 
the  temperature  to  which  the  filings  are  sub- 
jected. It  is  possible  to  carry  the  process  so 
far  as  to  oxidize  the  tm  and  render  the  alloy 
useless  ;  this  is  safeguarded  against  by  adoptmg 
the  method  described  above.     From  the  fore- 


going it  will  be  seen  that  an  unmodified  silver- 
tin  aUoy,  which  is  to  be  comminuted  and  re- 
served for  future  use,  will  be  one  containing  a 
larger  amount  of  silver  than  65  per  cent.  It  will 
be  found  to  be  somewhere  in  the  neighbourhood 
of  70  per  cent,  but  the  actual  amount  wfil 
depend  on  the  purity  of  the  metals  employed, 
and  must  be  determined  independently  for  each 
batch  of  metals  as  received  from  the  refiners. 

The  Action  of  the  Oral  Fluids  on  Dental 
Amalgams. — With  the  exception  of  the  binary 
alloy  of  copper  and  mercury,  dental  amalgams 
are  practically  insoluble  in  the  oral  fluids. 
Most  of  them,  however,  become  tarnished  more 
or  less  speedily  in  the  mouth,  owing  to  the 
action  of  the  sulphuretted  hydrogen  i^resent, 
and  it  is  difficult  to  see  how  this  can  be  entirely 
prevented,  so  long  as  silver  forms  one  of  their 
principal  constituents.  A  content  of  copper 
also  tends  to  increase  then-  liability  to  discolour. 
Zinc,  on  the  other  hand,  even  in  quite  small 
quantities,  owing  to  the  fact  that  it  forms  a 
white  sulphide,  helps  to  maintam  the  colour 
of  the  alloy,  as  jjrobably  also  does  the  addition 
of  a  little  gold.  It  is  possible,  too,  that  the 
presence  on  the  surface  of  the  filling  of  uncom- 
bined  portions  of  silver,  in  an  imperfectly 
amalgamated  alloy,  may  be  a  factor  increasing 
discoloration. 

Stauiing  of  the  tooth  tissue  is  due  to  the 
penetration  of  the  sulphides  of  the  metals  used, 
resulting  from  the  presence  of  moisture  between 
the  filling  and  the  cavity  walls.  It  may  follow 
shruikage  of  the  plug,  imperfect  adaptation  of 
the  fUling,  or  want  of  care  in  the  preparation 
of  the  cavity.  Discoloration  is  more  marked 
in  pulpless  teeth,  and  in  those  portions  of  the 
dentme  in  which  dead  dentinal  fibrils  are  pre- 
sent, such  as  frequently  occur  when  the  cavity 
is  large,  and  the  fibrils  have  been  cut  off  from 
their  connection  with  the  pulp  (4,  p.  315). 
The  character  of  the  staining  depends  upon 
the  constituents  of  the  alloy ;  it  is  usually  a 
greyish  black.  Certain  acids,  however,  acting 
upon  copper,  produce  staming  of  a  blue,  green, 
or  purple  colour.  All  discoloration  may  be  pre- 
vented by  properly  lining  the  cavity  with  one 
of  the  osteo-plastic  cements. 

Another  point  that  must  be  taken  into  con- 
sideration when  dealing  with  the  action  of  the 
oral  fluids,  is  the  electro-motive  force  that  is 
occasionally  established  between  two  fillings 
made  from  different  metals,  such  as  amalgam 
and  gold,  or  between  an  amalgam  filling  and 
a  gold  clasp  on  a  denture,  or  a  metal  crown. 
Such  galvanic  action  not  uncommonly  occurs 
when  the  reaction  of  the  oral  secretions  is  acid 
and  the  amalgam  is  new  and  untarnished.  It 
is  induced  by  the  different  metals  acting  as 
electrodes,  and  the  oral  fluid  as  the  electrolyte, 
and  is   most  marked   when  the  two  metals  are 


390 


widely  separated  in  the  voltaic  series.  It  thus 
happens  that  the  impact  of  a  newly  made 
amalgam  fillmp;  on  another  fiUiiig  made  of  gold 
in  a  different  tooth,  or  similar  conjunction 
of  two  metals,  results  m  a  sharp  pain  being 
felt  in  the  tooth  containing  the  amalgam.  A 
similar  residt  ensues  when  the  filling  is  touched 
with  a  steel  instrument,  or  with  the  nickel  rim 
of  a  mouth  mirror.  The  action  is  very  marked 
■with  high-grade  silver  aUoys  that  also  contain 
zinc,  and  particularly  so  when  these  alloys  are 
used  to  repair  old  fillings  made  from  copper 
amalgam.  It  is  quite  jjrobable  that  some  of 
the  wasting  of  copper  amalgam  in  the  mouth 
may  be  due  to  electrical  action,  and  the  darken- 
ing of  gold  fillings  when  coexistent  ui  the  mouth 
with  amalgam  fiUmgs  may  be  attributed  to  the 
same  cause. 

Conductivity  for  Heat. — As  might  be  expected, 
amalgam  fillings  are  good  conductors  of  ther- 
mal changes ;  in  this  respect,  however,  they  are 
inferior  to  gold,  but  possess  a  higher  rate  of 
conductivity  than  do  the  osteo-plastic  cements. 

Modified  Silver-tin  Alloys. — Small  quantities 
of  other  metals  are  often  added  to  sUver-tin 
alloys  in  order  to  secure  or  enhance  certain 
desirable  properties.  Such  metals  are  gold, 
copper,  zinc,  occasionally  j)latmum,  and  more 
rarely  bismuth.  Cadmium  also  was  used  for- 
merly, but  has  been  abandoned  owmg  to  the 
fact  that  it  forms  a  yellow  sulphide,  \^hich 
under  certam  conditions  stained  the  dental 
tissues.  Considerable  difference  of  opinion 
exists  as  to  the  results  accruing  from  such 
modifications.  It  is  claimed  that  gold,  when 
added  to  the  extent  of  five  per  cent,  renders 
amalgamation  more  easy,  improves  the  colour 
of  the  filling,  hastens  its  settmg,  and  reduces 
any  tendency  it  may  have  to  contract.  Black 
on  the  other  hand,  is  of  opinion  that  gold  has 
no  influence  on  the  contraction  of  the  alloy, 
whilst  it  increases  the  liability  to  flow,  and  to 
some  extent  raises  its  crusjiing  stress. 


It  has  been  already  indicated  that  the  binary 
alloy  of  copper  and  mercury  forms  the  most 
rigid  amalgam — one  showing  the  least  tendency 
to  flow.  The  addition  of  five  per  cent  of  copper 
to  a  silver -tin  alloy  makes  it  much  more  rigid, 
and  at  the  same  time  increases  its  crushing 
stress,  and  apparently  also  hastens  the  settmg 
of  the  mass.  It  is  the  most  useful  of  all  the 
metals  added  to  modify  a  sUver-tin  alloy.  Its 
presence,  however,  promotes  discoloration  of 
the  filling,  although  this  may  be  partly  con- 
trolled by  a  small  content  of  zinc  or  gold. 
Some  observers  claim  that  the  mclusion  of  copper 
in  a  dental  amalgam  lessens  the  liability  to 
a  recurrence  of  caries,  as  the  salts  of  the  metal 
have  a  preservative  and  antiseptic  action  on 
the  tooth  tissue ;  this,  however,  needs  corrobora- 
tion. The  addition  of  zinc  to  a  silver-tm  aUoy 
materially  helps  to  preserve  its  colour.  As  a 
general  rule  it  promotes  expansion,  which  is 
contmued  over  a  long  period  and  renders  the 
amalgam  so  unstable  as  to  contra-mdicate  its 
use.  Alloys  contaming  zmc  are  much  harsher 
when  commuiuted,  they  amalgamate  less  readily, 
requu'ing  more  mercurj'  than  an  unmodi- 
fied alloy,  their  tendency  to  flow  is  reduced, 
but  their  crushing  stress  remains  practically 
unaltered. 

Fletcher  first  introduced  platinum  as  a 
constituent  of  amalgam  alloys,  claiming  that 
its  presence,  when  combined  with  a  small 
percentage  of  gold,  both  hastened  the  settmg 
and  rendered  the  mass  more  rigid  (16,  p.  39). 
Black  is  of  of)inion  that  platinum  increases 
the  flow  and  yields  a  plug  that  contracts 
steadily,  whether  gold  is  present  in  the  alloy 
or  not. 

Bismuth  is  very  seldom  used.  It  facilitates 
amalgamation,  but  makes  a  somewhat  dirty 
and  sticky  mix  (16,  p.  64). 

The  following  table  shows  the  results  obtained 
from  experiments  conducted  by  Black  (4,  p. 
312)— 


Formulae 

How  pre- 

Percentage 

Shrink- 

Expan- 

Flow 

Crushing 

Modifying 

Metal           Silver 

Tin 

pared 

of  Mercury 

age 

sion 

Stress 

65 

35 

Fresli  cut 

52-33 

0 

1 

3-67 

290 

65 

35 

Annealed 

33-00 

10 

0 

5-00 

335 

66-75 

33-25 

Fresh  cut 

51-52 

0 

4 

3-35 

329 

66-75 

do. 

Annealed 

33-53 

7 

0 

5-06 

380 

Gold  5       . 

61-75 

33-25 

Fresh  cut 

47-56 

0 

1 

4-62 

330 

do. 

do. 

Annealed 

30-35 

7 

0 

6-07 

395 

Copper  .")  . 

do. 

do. 

Fresh  cut 

53-65 

0 

23 

2-38 

300-343 

do. 

do. 

Annealed 

35-60 

5 

0 

3-50 

416-450 

Zinc  5 

do. 

do. 

Fresh  exit 

56-65 

0 

68 

1-83 

200-290 

do. 

do. 

Annealed 

40-65 

0 

9 

2-07 

250-345 

Platinum  5 

do. 

do. 

Fresh  cut 

51-87 

0 

9 

9-68 

200-273 

do. 

do. 

•  Annealed 

37-33 

7 

0 

8-20 

250-352 

Bismuth  5 

.        .          do. 

do. 

Fresh  cut 

46-26 

0 

0 

4-78 

250-288 

do. 

do. 

Annealed 

23-67 

6 

0 

5-58 

308 

391 


The  follovvmg  list  gives  the  formulae  of  some 
of  the  modified  silver -tm  alloys  in  general  use — 


surface  of  the  mercury ;  whilst  the  anode  con- 
sists of  copper  turnings  enclosed  in  a  muslin 


1      Silver 

Tin 

Copper 

Gold 

Zinc 

Platinum  | 

C.A.S.  Alloy  . 

.    1       67-18 

27-24 

4-48 

1-1 

Tulloeh's  Alloy   (1) 

.    j      69-5 

25-5 

4 

1 

(2)       . 

.    j      66 

29 

4 

1 

Fletcher's  Gold  Alloy  . 

.   j      40 

56 

4 

Platinum  and  Gold  Alloy           43-35 

50-35 

1-65 

3-35 

1-3 

Fellowship  Alloy  . 

67-73 

■  27-24 

4-71 

1-23 

True  Dental  Alloy 

.    1       65-82 

27-94 

3-86 

2-38       : 

Flagg's  (Submarine)    . 

60 

35 

5 

1 

„        (Contour)  . 

58 

37 

5 

(Facing)    . 

37 

35 

5 

3 

Eckfeldt's  (Standard)  . 

.   1      52 

40-6 

3 

4-4 

1 

Binary  Amalgams. — The  only  buiary  amal- 
gams employed  in  dentistry  as  filluig  materials 
are  those  of  copper  and  palladium ;  the  latter, 
however,  is  now  but  seldom  used.  Both  con- 
sist of  a  combmation  of  the  precij)itates  of  the 
metals  with  mercury. 

Copper  Amalgam. — This,  which  was  intro- 
duced under  the  name  of  Sullivan's  Cement, 
may  be  prepared  by  precipitating  metallic  copper 
from  a  weak  and  slightly  acid  solution  of  copper 
sulphate  by  rods  of  pure  zinc  or  iron.  The 
precipitate  is  collected  and  thoroughly  washed 
with  sulphuric  acid,  and  finally  with  water ; 
it  is  then  dried  and  mixed  with  twice  its  weight 
of  pure  mercury,  by  trituration  m  a  mortar. 
Amalgamation  does  not  take  place  very  readily 
at  first,  but  may  be  facilitated  by  heat,  or  by 
the  addition  of  a  small  quantity  of  mercuric 
nitrate.  When  thoroughly  mcorporated,  the 
mass  LS  made  mto  pellets  of  suitable  size,  which 
are  then  allowed  to  harden.  These  pellets 
possess  the  property  of  becoming  softened  again 
when  strongly  heated,  and  may  then  be  tri- 
turated in  a  mortar  and  worked  up  uito  a 
plastic  mass,  \\hich  is  then  ready  for  packing 
into  a  tooth  cavity.  Boyd-Wallis  is  of  opinion 
that  copper  precipitated  by  iron  produces  an 
amalgam  superior  to  that  made  from  copjser 
precipitated  by  zinc  (6). 

Another  method  of  preparation  consists  in 
depositing  the  copper  electroIyticaUy  directly 
into  the  mercury.  A  quantity  of  mercury  is 
placed  at  the  bottom  of  a  suitable  vessel,  and 
covered  with  a  saturated  solution  of  copper 
sulphate.  The  mercury  is  made  the  cathode 
by  introducing  a  copper  wire,  which  is  attached 
to   tlie   zinc   pole   of   a   battery,    beneath   the 


bag,  which  is  suspended  from  a  wire  attached 
to  the  carbon  pole  of  the  battery.  The  action 
is  contmued  until  the  mercury  at  the  bottom 
of  the  vessel  is  completely  saturated  with  the 
precipitated  copper  (20).  The  mass  is  collected 
and  thoroughly  washed,  and  the  excess  of 
mercury  squeezed  out.  It  Ls  then  made  mto 
pellets  of  a  requked  size. 

Copper  amalgam  possesses  many  jjroperties 
that  render  it  suitable  as  a  fillmg  material. 
It  is  the  most  rigid  of  all  dental  amalgams  and 
undergoes  no  change  of  volume  whilst  hardening. 
Its  colour  is  objectionable  from  the  fact  that  it 
quickly  becomes  coated  with  a  black  sulphide, 
from  exposure  in  the  mouth,  and  unless  special 
precautions  are  taken,  it  is  liable  to  stain  the 
tooth  tissues.  The  first  of  these  undesirable 
properties,  however,  is  of  minor  importance 
when  the  use  of  the  material  is  restricted  to 
cavities  that  are  at  the  back  of  the  mouth  and 
hidden  from  view ;  whilst  the  second  may  be 
obviated  by  properly  Iming  the  cavity  \vith  one 
of  the  osteo-plastic  cements.  Unfortunately, 
however,  the  amalgam  undergoes  dismtegration 
in  the  mouth,  which  renders  it  inadmissible 
as  a  permanent  filling  material.  As  the  surface 
of  the  filling  is  attacked  by  the  sulphuretted 
hydrogen  present,  it  becomes  converted  into 
copper  sulphide,  and  the  combined  mercury  is 
liberated.  In  crown  cavities  the  sulphide  is 
washed  away  as  formed.  In  approximal  cavi- 
ties, particularly  at  cervical  margins,  the  dis- 
integration is  very  marked,  resulting  m  the 
formation  of  a  new  cavity,  partly  from  the 
loss  of  fiUmg  material,  and  partly  owing  to 
the  recurrence  of  caries.  In  this  cavity,  little 
globules   of   free   mercury   may   frequently   be 


392 


observed.  The  rate  of  wasting  of  the  plug 
appears  to  depend  upon  the  density  of  the 
filling,  the  amount  of  copper 


it  contains,  the 


Fig.  455. 


{Trans.    Odont.   Soc.) 


amount  of  sulphuretted  hydrogen  present,  and 

the  degree  of  friction  to  which  it  is  subjected. 

In   short,  copper   amalgam   should 

never  be  used  in  a  cavity  of  which 

any  of  the  margms  are  hidden  from 

view. 

As  already  mentioned,  certain 
therapeutic  and  preservative  pro- 
perties have  been  claimed  for  this 
material.  It  is  more  probable  that 
its  preservative  qualities  are  due  to 
the  fact  that  it  does  not  contract, 
and  hence,  so  long  as  it  remains 
intact,  forms  a  watertight  plug  (2). 

It  is  stated  tliat  the  addition  of 
from  two  per  cent  to  five  per  cent 
of  tm  to  a  copper  amalgam  lessens 
its  tendency  to  waste  in  the  mouth, 
and  also  improves  its  colour. 

Palladium  Amalgam. — An  amalgam 
composed  of  precipitated  palladium 
and  mercury  was  formerly  much  used 
in  this  country  ;  it  is  now  but  seldom 
employed.  This  is  no  doubt  partly 
due  to  the  great  advance  in  the  cost 
of  the  metal.  The  precipitate  is 
prepared  by  dissolving  palladium 
foil  in  nitro-hydrochloric  acid,  and 
precipitating  the  metal  from  a 
dilute  and  slightly  acid  solution  of 
its  salt  by  rods  of  zinc.  The  grey- 
black  powder  thus  obtained  is  col- 
lected, and  thoroughly  washed  free 
of  all  acid  with  hot  water.  It  is 
then  dried,  and  should  be  kept  in  a 
tightly  stoppered  bottle,  as  it  seems  to  lose  its 
affinity  for  mercury  after  exposure  to  the  air. 
When  triturated  together  in  a  mortar,  paUadium 


and  mercury  do  not  combine  at  once ;  when 
the  union  does  occur,  it  is  somewhat  sudden, 
and  a  certain  amount  of  heat  is  generated, 
indicating  a  chemical  union. 

Palladium  amalgam  sets  rapidly, 
yielding  a  plug  that  exliibits  a  large 
degree  of  expansion,  which  continues 
for  a  fairly  long  period.  In  the  mouth 
the  fiUmg  becomes  jet  black  in  colour ; 
it  does  not,  however,  stain  tlie  tooth 
tissue. 

The  Mixing  of  Dental  Amalgams. — It 
has  already  been  indicated  that  the 
amount  of  mercury  required  to  make  a 
mass  that  is  easily  manipulated  and 
that  may  be  condensed  without  diffi- 
culty varies  with  the  constitution, 
character,  and  method  of  preparation 
of  the  primary  alloy.  Some  excess  of 
mercury  over  and  above  what  is  neces- 
sary to  satisfy  the  chemical  affinities  of 
the  constituent  metals  is  required,  as 
otherwise  the  mass  cannot  be  rendered 
sufficiently  plastic ;  but  the  limitation 
of  this  excess  to  a  uniform  minimum,  as  well 
as  evenness  m  its  distribution,  are  matters  of 


Fig. 


456. — TuUoch's  amalgam  alloy  measure. 

(Trans.    Odont. 


Soc.) 


the  first  importance.  Amalgamation  is  effected 
in  various  ways  :  by  trituration  with  pestle 
and  mortar ;  by  shakmg  the  finely  divided  alloy 


393 


and  mercury  together  iii  a  test  tube ;  or  by 
merely  rubbing  tliem  together  ui  the  palm  of 
the  hand.  The  first  of  these  is  the  method 
most  generally  adopted  and  is  the  best ;  further, 
the  mortar  should  be  warmed. 

The  filings  having  been  incorporated  with 
the  mercury,  it  is  a  common  practice  to  express 
some  of  the  excess  mercury  by  squeezing  it  out 
through  a  cloth  or  piece  of  chamois  leather. 
Such  a  procedure  cannot  but  lead  to  a  lack 
of  uniformity  in  the  results  achieved.  If 
some  of  the  expressed  mercury  Is  exammed, 
and  a  globule  of  it  made  to  roll  do«ii  a  smooth 
incline,  it  will  at  once  be  observed  that  it  is 
contanimated  by  some  other  metal,  as  evidenced 
by  the  fact  that,  when  rolling,  it  does  not  main- 
tain the  form  of  a  perfect  sphere.  With  the 
mercury  have  been  extracted  varying  propor- 
tions of  the  other  constituents  of  the  alloy, 
gold  and  tin  being  the  chief  losers.  This  may 
be  confirmed  by  treating  a  little  of  the  expressed 
mercury  in  a  test  tube  w  ith  dilute  nitric  acid ; 
the  mercury,  together  with  any  silver,  is  dis- 
solved, \\liilst  a  residue  is  left,  which  m  the 
case  of  tui  alone  is  white  (metastannic  acid), 
and  in  the  event  of  gold  also  being  present  is 
purple  (Purple  of  Cassius).  The  amount  of 
tin  removed  ^^ith  the  excess  of  mercury  is 
proportional  to  the  quantity  of  the  latter  metal 


of  silver  38-8  per  cent,  tin  49  per  cent,  gold 
12  per  cent,  it  was  found  that,  after  amalgama- 
tion  with    a   large    quantity   of   mercury,   and 


_^_^^p^ 


Fig.  457. — ^Tulloch's  amalgam  alloy  measure. 

(Trails.  Odont 

that    is    expressed,    being    approximately    one 
per  cent  (17).      As  the  result  of  an  experiment 
conducted  by  Brisleo,  with  an  alloy  composed 
13* 


Fig.  458. 


removal  of  the  excess  by  squeezing,  the  alloy 
then  contained  silver  67  per  cent,  tin  31  per 
cent,  gold  2  per  cent  (7).  It  is 
obvious  that  with  such  haphazard 
methods  as  those  commonly  adojited, 
the  amount  of  mercury  removed 
being  dependent  upon  the  caprice  of 
the  operator,  uniform  results  with 
dental  amalgam  fiUmgs  caimot  pos- 
sibly be  obtained ;  and  the  differ- 
ences will  be  further  accentuated 
by  variations  m  the  amount  of 
mercury  expressed  during  the  actual 
insertion  of  the  filling. 

In  order  to  ensure  a  uniform  mix, 
from  which  it  is  unnecessary  to  ex- 
f)ress  any  mercury,  several  balances 
for  easily  weighing  definite  quantities 
of  mercury  and  alloy  filings  have 
been  devised ;  that  designed  bv  J.  B. 
Parfitt  is  excellent  (Fig.  455).  Of 
a  similar  nature  are  the  appliances 
introduced  by  Tulloch  (24)  (see  Figs. 
456,  457).  These  machines  may  be 
adjusted  to  throw  a  desired  amount 
of  mercury  or  alloy,  and  prove  very 
satisfactory  in  use.  The  appliance 
for  measuring  the  filings  may  be 
replaced  by  the  little  spoon  (Fig. 
458) ;  the  weight  of  the  filings  it 
contains  when  quite  full  having 
been  ascertained,  the  mercury  appliance  may 
be  adjusted  to  throw  the  required  amount 
to   produce   the   desired   mis.     A   spoon   with 


Soc.) 


394 


t< 


[ 


a    capacity    of    five   grains    will    prove    most 
convenient. 

Methods  of  Packing. — The  technique  involved 
in  the  preparation  of  cavities  for  the  reception 
of  fillings  is  dealt  with  in 
Chapter  XIX.  Briefly  it  may 
be  said  that  such  cavities 
should  possess  strong  and  as 
nearly  as  possible  straight 
walls,  with  squared  edges, 
whilst  as  broad  a  seat  as  may 
be  is  secured  for  the  fillmg. 
The  cavity  should  be  com- 
pletely lined  with  one  of  the 
osteo-plastic  cements,  prefer- 
ably an  oxy-phosphate  of  zinc. 

The  packing  of  the  amalgam 
should  be  commenced  before 
the  cement  has  hardened,  in 
the  mamier  recommended  by 
Baldwui  (3),  ui  order  to  take 
advantage  of  the  adhesive 
qualities  of  the  cement,  which 
also  serves  to  reduce  the  con- 
ductivity of  thermal  changes 
through  the  amalgam  to  the 
tooth-pulp.  The  best  results 
are  obtained  by  using  the  alloy 
in  small  pieces,  and  thoroughly 
condensing  them  into  place  with 
heavy  pressure.  Plugger  points 
with  finely  serrated  flat  surfaces 
are  to  be  preferred  to  ball- 
headed  burnishers  (Fig.  459), 
and  here  agam  the  importance 
of  properly  mixed  amalgam  is 
seen.  If  the  mix  is  too  soft,  it 
cannot  be  made  to  stay  in 
close  apposition  with  the  cavity 
walls  :  as  soon  as  the  pressure  is 
removed  there  is  a  tendency 
for  the  compressed  mass  to 
rebound,  as  it  were,  after  the 
manner  of  a  sponge  (18).  Pre- 
cautions must  be  taken  to 
remove  any  portions  of  the 
cement  lining  that  may  have 
encroached  on  the  enamel  mar- 
gins, in  order  that  the  whole  of 
the  exposed  surface  of  the 
filling  may  be  of  metal.  With 
compound  cavities  a  matrix 
(see  Chapter  XIX)  is  indis- 
pensable, not  oiJy  to  assist  in 
securing  the  desired  contour, 
but  also  to  allow  of  the  amalgam  being  evenly 
condensed.  There  are  many  methods  of  packing 
amalgam,  all  of  which  are  directed  towards 
securing  an  even  distribution  of  the  mercury 
and  a  rapid  setting  of  the  plug. 

KLirby   was   the    first   to   suggest   using   two 


mixes,  one  containing  more  mercury  than  the 
other,  and  employing  the  former  for  commencing 
the  filling,  and  the  latter  for  finish mg ;  by  this 
means   the   excess   of   mercury,    which   always 


n 


Fig.   459.- 


-Hopson's  Amalgam  Pluggers. 

(Messrs.  Claudhis  Ash,  Sons  <fc  Co.,  Ltd.] 


works  to  the  surface  as  the  amalgam  is  con- 
densed, makes  up  the  deficiency  in  the  portion 
of  the  alloy  that  is  inserted  last  (19).  The 
same  result  may  be  achieved  when  definite 
quantities  of  mercury  and  alloy  are  taken,  if, 
when   partlj'   incorjjorated    with   the   mercury, 


395 


a  portion  of  the  mix  is  placed  on  one  side  to 
be  used  in  completing  the  filling.  Other  methods 
consist  ill  removing  any  excess  of  mercury,  after 
the  addition  of  each  fresh  piece  of  amalgam, 
by  pressure  with  pledget  of  amadou  or  cotton-  i 
wool.  Loosely  rolled  cylinders,  or  the  foU,  of 
tm,  silver,  or  gold,  when  burnished  on  to  the  \ 
surface  of  the  amalgam,  will  absorb  and  thus 
remove  the  excess  mercury.  As  already  in- 
dicated, however,  these  latter  methods  lead  to  a 
lack  of  uniformity  in  the  resultant  fillings. 

The  cavity  being  completely  filled,  attention 
must  be  given  to  its  correct  occlusion  with 
opposing  teeth.  When  a  matrix  is  used  this 
may  be  done  before  its  removal ;  any  chance 
of  the  filling  being  fractured  by  being  bitten 
upon  is  thereby  prevented.  In  the  removal 
of  the  matrix  much  care  is  needed  to  avoid 
displacing  some  portion  of  the  plug.  Any 
overlap  at  the  cervical  margin  is  removed  by 
a  thin  burnisher,  and  finished  off  with  a  piece 
of  rubber-dam  or  sUk  ribbon ;  the  position  and 
character  of  the  contour  m  relation  to  the 
adjacent  tooth  and  the  actual  contact  point 
are  of  great  importance.  Finally,  a  burnisher 
may  be  employed  to  ensure  the  close  adaj)tation 
of  the  filling  to  the  cavity  marguis.  At  a 
subsequent  visit  the  fiUing  is  carefully  polished, 
with  sand-paper  and  cuttle-fish  discs  and  strips, 
and  finally  \\ith  a  soft  felt  wheel  charged  with 
pumice.  During  the  polishing  process  much 
care  is  needed  to  avoid  destroying  the  correct  ' 
contour  of  the  filling  by  the  excessive  use  of 
polishmg  discs,  and  the  use  of  some  form  of 
separator  to  afford  free  access  is  mdicated. 

For  aesthetic  reasons  amalgam  should  be 
excluded  from  cavities  in  w'hich  it  is  readily 
seen ;  its  appropriate  situation  is  in  the  pre- 
molar and  molar  regions.  It  is  especially 
useful  in  large  compound  cavities,  and  also  in 
those  that  extend  under  the  gum  margin, 
where  it  is  difficult  or  impossible  to  maintaui 
absolute  dryness  for  any  length  of  time. 

The  Physical  Examination  of  Dental  Amalgam 
Alloys. — Change  of  volume  m  a  dental  amalgam 
may  be  determined  in  various  ways.  A  some- 
what rough-and-ready  method  is  that  of  packing 
a  small  quantity  into  a  small  glass  tube,  about 
i  inch  in  diameter  and  closed  at  one  end. 
AVlien  such  a  tube  is  packed  partly  fuU,  and 
the  remainder  filled  in  w  ith  red  ink  or  aniline 
dye,  any  contraction  of  the  amalgam  would 
be  indicated  by  the  leakage  of  the  coloured 
fluid  between  the  plug  and  the  side  of  the 
tube.  On  the  other  hand,  expansion  may  be 
noted  by  packing  a  similar  tube  quite  full, 
taking  care  that  the  plug  is  made  flush  with 
the  open  end,  and  a  subsequent  examination 
with  a  strong  lens. 

A  more  accurate  and  scientific  method  of 
a.scertaining  changes  of  volume  entails  the  use 


of  a  micrometer,  a  delicately  constructed  instru- 
ment, which  records  on  a  dial  or  scale  variations 
measured  to  j^l^^  inch.     Such  an  instrument 


is  shown  in  Fig.  460.  A  plug  of  amalgam 
is  made  in  the  motild  (Fig.  461)  and  is  placed 
in  position  m  the  micrometer,  and  the  degrees 
of  contraction   are   noted   from  time  to    time. 


1-ic:.    41.1. 


The  disadvantage  pertaining  to  this  mstrument 
is  that  only  one  experiment  can  be  conducted 
with  it  at  a  time. 

Another  useful  form  of  micrometer  for  the 


396 


examination  of  amalgam  alloys  is  that  designed 
by  Black  and  shown  in  Fig.  462.  For  use  with 
this' instrument  moulds  known  as  Wedelstaedt 


Fig.  462. 

(G.  V.  Bl^ck  :  Operative  Dentistry. 


tubes  are  employed.  These  tubes  consist  of 
little  steel  blocks  (Fig.  463)  m  which  cavities 
!  inch  in  diameter  and  \  inch  deejj  are  drUled. 
The  bottoms  of  the  cavities  are  fiat  and  the 
margins  are  ground  absolutely  true  and  flat. 
Amalgam  having  been  packed  into  the  tube,  it 
is  placed  in  the  position  mdicated,  and  any 
change  in  form  is  registered  by  the  pointer  on 
the  scale. 

Amalgam  packed  hi  a  Wedelstaedt  tube  may 
be  examined  for  shruikage  microscopically  by 
placing  it  on  the  stage  of  a  microscope,  and 
rotating  it  so  as  to  bring  the  whole  of  the 
cavity  margin  into  the  field.  Finally,  the 
specific  gravity  of  the  alloy  may  be  computed 
from  the  amounts  of  its  constituents,  and  com- 


pared with  what  it  is  actually  found  to  possess 
by  experiment.  Should  the  alloy  be  found  to 
posses,"  a  density  greater  than  that  of  its  com- 
puted mean  specific  gravity, 
contraction  has  occurred ; 
on  the  other  hand,  a  decrease 
in  the  density  indicates  ex- 
pansion. 

The  amount  of  stress  re- 
quired to  crush  a  mass  of 
fully  hardened  amalgam 
may  be  determined  by  the 
use  of  an  mstrument  kiiown 
as  a  dynamometer,  such  as 
that  shown  ui  Fig.  464. 
Small  cubes  of  amalgam 
measurmg  J  inch  are  made 
in  a  moulcl  (Fig.  465)  and 
allowed  five  days  to  har- 
den ;  they  are  then  tested  in 
the  dynamometer,  and  the 
number  of  pounds  pressure 
required  to  crush  them,  as 
indicated  on  the  dial,  noted. 
An  attachment  for  measur- 
ing the  breaking  stram  of 
J  inch  bars  of  amalgam 
may  be  used  with  the  same 
instrument. 

Metallography  of  Dental 
Amalgams. — Much  attention 
has  been  given  m  recent 
years  to  the  microscopic 
structure  of  metals  and 
alloys,  and  to  the  associa- 
tion of  the  structures  re- 
vealed with  the  physical 
properties  possessed  by  the 
metals. 

The  method  adopted  of 
making  such  an  examma- 
tion  is  as  follows  :  A  portion 
of  the  alloy  is  taken  and 
made  perfectly  flat.  It  is 
then  carefully  polished  until 
all  scratches  are  entirely  removed,  and  the 
surface   is   etched   by   allowing  some    suitable 


Fig.  463. 
(G.  V.  Black  :  Operative  Dentistry.) 

dUute  acid  to  remain  in  contact  with  it.  The 
result  is  that  a  pattern  is  produced  by  the 
degree  of  action  of  the  acid  on  the  different 


397 


metals  present  in  the  alloys ;  the  etched  surface 
is  then  examined  under  the  microscope.  BrLslee 
(7)  and  Fenchel  (13)  have  examined  amalgam 
alloys  in  this  manner  with  uiteresting  results. 
It  has  been  shown  that  with  many  amalgam 
alloys  the  crystals  that  first  form  disappear  and 
are  replaced  by  others  differently  constituted, 
and  that  this  process  continues  until  a  condition 
of  equilibrium  is  reached ;  that  with  an  alloy 
of  a  low  meltuig  point  crystals  form  more 
readily  out  of  the  solution  in  a  condition  of 
equilibrium,  and  that  this  is  facilitated  by 
having  the  pestle  and  mortar  and  the  pluggers 
warmed ;  that  in  some  instances  unamalgam- 
ated  pieces  of  metal  are  merely  joined  together 
by  masses  of  amalgam,  and  that  changes 
continue  to  occur  untU  the  mercury  has  com- 
pletely diffused  throughout  the  plug. 

2.   OSTEO-PLASTIC  CEMENTS 

The  filling  materials  kno\vii  by  the  generic 
term  of  osteo-plastic  cements  consist  of  a 
powder  and  liquid,  which  when  incorporated 
together  set  more  or  less  rapidly,  somewhat 
after  the  manner  of  builder's  cement,  to  form 
a  hard  and  in  most  cases  adliesive  solid. 

There  are  five  varieties  in  common  use ;  of 
these,  four  are  basic-zinc  compounds,  viz.  oxy- 
phosphate,  oxy-chloride,  and  oxy-sulphate  of 
zmc,  and  oxy-phosphate  of  copper,  whilst  the 
fifth  is  a  silicious  compound.  There  is  no  stan- 
dard formula  for  any  variety,  each  manufacturer 
slightly  modifying  his  particular  product,  both 
■with  regard  to  its  composition  and  method  of 
preparation  ;  nor  have  tlie  chemical  and  physical 
properties  of  these  cements  been  investigated 
to  the  same  extent  as  those  of  dental  amalgams. 

Oxy-phosphate  of  Zinc. — The  powder  is  com- 
posed of  calcined  zinc  oxide  to  which  small 
quantities  of  other  materials  are  added  for  the 
purpose  of  increasino;  the  hardness  of  the  cement 
and  of  modifying  its  colour;  the  liquid  is  one 
of  the  forms  of  phosphoric  acid,  often  modified 
by  the  addition  of  small  amounts  of  zinc  oxide 
and  alumina.  In  the  preparation  of  the  powder 
it  is  of  the  first  importance  that  the  zinc  oxide 
Hsed  should  be  quite  pure.  The  commercial 
form  commonly  contains  imjiurities,  such  as 
white  lead,  chalk,  and  arsenic.  To  ensure 
purity,  therefore,  it  is  best  prepared  by  adding 
sodium  carbonate  to  a  solution  of  zinc  sulphate, 
which  yields  a  white  precipitate  of  zinc  car- 
bonate. This  precipitate  is  collected,  washed, 
and  dried ;  finally  it  is  heated  to  drive  off  the 
carbonic  acid,  and  zinc  oxide  is  left  in  the  form 
of  white  powder. 

The  zinc  oxide  is  placed  in  a  perfectly  clean 
and  previously  annealed  clay  crucible,  and 
calcined  at  a  bright  red  heat  in  a  muffle  furnace 
for  several  hours.     During  the  process  the  oxide 


shrinks  very  considerably,  whilst  its  colour  is 
changed  to  a  pale  yellow;  with  a  very  higli 
temperature  a  deeper  yellow  is  produced,  and 
the  powder  is  converted  into  a  semi-vitrified 
mass.  The  calcined  product  is  then  removed 
from  the  crucible  and  ground  by  machine  mills 
to  a  very  fine  powder.  The  substances  added 
with  the  object  of  imparting  hardness  and 
better  wearing  properties  to  the  cement  include 


1 


tmmtf, 


mw^ 


B 

4 

1 

j 

1 

•  -i- 

Fig.  464. 

sUex,  borax,  powdered  glass,  oxide  of  tin,  and 
oxide  of  bismuth.  To  make  the  cement  set 
more  quickly,  the  oxides  of  magnesium  and 
aluminium  in  small  quantities  are  sometimes 
incorporated  with  the  jjowder.  To  secure  a 
desired  shade,  colouring  matters  of  the  nature 
of  yellow  ochre,  ferric  oxide,  titanium  oxide, 
gold  oxide,  powdered  slate,  etc.,  are  employed. 
The  f  oUomng  formulae  have  been  published — 
(1)  Zinc  oxide  30  parts,  borax  2  parts,  silex 
1  part. 


398 


The  constituents  are  thoroughly  ground 
together  and  then  calcined  in  the  manner 
already  described.  After  removal  from  the 
crucible  they  are  again  ground  to  the  finest 
powder,  together  with  a  further  3  parts  of  zinc 
oxide  (12). 

(2)  Zinc  oxide  200  f)arts,  silex  8  parts,  borax 
4  parts,  ground  glass  5  parts. 

The  component  parts  are  levigated  under 
water    to    ensure    their    complete    admixture, 


OLj 


Fig.  465. 
(G.  V.  Black 


Operative  Dentistry. ) 


then  dried  by  evaporation,  calcined  at  a  white 
heat,  and  finally  reduced  to  the  finest  possible 
powder. 

(3)  Zinc  oxide  82"5  parts,  aluminium  silicate 
8'5  parts,  magnesia  7"5  parts,  and  alumina 
1-5  parts  (9). 

It  is  advisable  to  keep  the  powder  in  tightly 
stoppered  bottles,  as  it  absorbs  moisture  and 
is  impaired  thereby. 

The  liquid  to  be  used  with  the  above  powder 
is  ijrepared  by  dissolving  glacial  phosphoric 
acid  in  distilled  water  and  applying  a  gentle 


heat  until  the  solution  assumes  a  syrupy  con- 
sistency. If  after  standing  crystals  apjjear  in 
the  liquid,  a  drop  or  two  more  of  water  should 
be  added ;  or  it  may  be  composed  of  phos- 
phoric acid  65  parts,  zinc  oxide  16  parts, 
alumina  6  parts,  and  water  13  jjarts  (9). 

Care  is  needed  in  mixing  these  cements,  as  the 
results  obtained  depend  very  largely  not  only 
on  the  purity  of  the  ingredients  and  the  fineness 
of  the  powder,  but  also  on  the  manner  in  which 
the  liquid  and  powder  are  incorpor- . 
ated.  A  drop  of  liquid  should  be 
removed  from  the  bottle  by  means 
of  a  glass  rod  or  sjjecially  constructed 
"dropper",  and  not  by  a  metal 
spatula ;  the  drop  of  liquid  should 
be  placed  at  one  end  of  a  clean  glass 
slab,  which  should  be  about  one  inch 
thick  and  six  inches  long  by  four 
^  inches  broad.  A  sufficiency  of  the 
/— V  po^\der  should  then  be  placed  on  the 
Y  \  slab  at  some  distance  from  the  liquid, 
\Jx  and  the  powder  gradually  drawn  into 
V-''  the  liquid  and  thoroughly  spatulated, 
backwards  and  forwards,  ^vith  a 
spatula  made  of  pure  nickel.  No 
more  poA\cler  should  be  used  than  is 
sufficient  to  produce  a  mix  that 
though  possessing  a  glazed  appear- 
ance yet  will  not  drop  from  the 
spatula.  Setting  is  hastened  by  heat 
and  retarded  by  cold. 

A  useful  and  ingenious  mixing 
slab,  devised  by  W.  R.  Humby,  is 
made  of  a  sheet  of  copper,  about  half 
an  inch  thick,  thickly  plated  -with 
nickel  to  lessen  as  much  as  possible 
any  chemical  activity.  The  copper, 
being  a  good  conductor,  absorbs  the 
heat  generated  during  the  crystal- 
lization of  the  mass,  and  thus  retards 
the  setting.  Such  a  slab  is  useful 
during  the  hot  days  of  summer,  and 
particularly  where  a  large  mix  is 
required,  as  is  sometimes  the  case 
when  setting  crowns  and  bridges. 
A  somewhat  similar  result  may  be 
secured  by  using  as  a  mixing  slab 
the  side  of  a  flat  glass  bottle  filled 
with  cold  water. 

A  well-made  and  properly  mixed  oxy-phos- 
phate  cement  yields  in  a  few  minutes  a  hard, 
closely  grained,  solid  mass  with  a  glazed  surface 
capable  of  adhering  to  any  dry  substance  against 
which  it  has  been  packed  while  still  plastic.  Its 
strength  and  adhesiveness  are  in  proportion 
to  the  fineness  of  the  powder  and  the  thorough- 
ness with  which  tlie  mixing  with  the  liquid 
has  been  conducted.  During  the  process  of 
hardening  some  of  these  cements  contract; 
many    are   also    j)orous,    more    jiarticularly   so 


399 


when  moisture  is  allo\\'ed  to  come  in  contact 
with  them  before  they  have  fully  set ;  those 
exliibiting  the  most  contraction,  however,  are 
the  least  porous.  They  are  attacked  and  dis- 
solved by  the  oral  fluids,  and  are  soluble  in  lactic 
acid  and  ammonium  salts,  and  hence  they  do 
not  make  permanent  fillings,  usually  requiring 
to  be  renewed  or  repaired  after  about  two 
years'  service.  In  a  few  mouths,  however,  they 
occasionally  last  for  many  years.  They  must 
not  be  placed  in  too  close  contact  ^\•ith  the 
dental  pulp,  as  this  organ  is  liable  to  be  irritated 
by  the  action  of  the  phosphoric  acid.  There 
is  also  the  possibility  of  arsenious  oxide  being 
present  in  the  powder,  as  zmc  and  arsenic  are 
often  associated  together  in  nature ;  the  usual 
method  of  preparation,  however,  would  probably 
eliminate  all  but  the  merest  trace.  Compared 
with  metal  fillings,  oxy-phosphates  are  poor 
conductors  of  thermal  changes,  but  at  the 
same  time  are  not  to  be  classed  -with  the  non- 
conductors, such  as  gutta-percha ;  they  also 
possess  slightly  antiseptic  properties.  Oxy- 
phosphate  cements  are  largely  used  to  form 
temporary  fillings. 

Small  pellets  of  the  cement,  mixed  as  de- 
scribed above,  are  taken,  and  rapidly  packed 
into  the  cavity  with  suitable  nickel-plated 
burnishers  and  spatulas.  It  is  important  that 
the  instruments  be  jierfectly  clean  and  brightly 
polished.  The  packing  shoukl  be  conducted 
in  such  a  mamier  as  just  to  fill  the  cavity  and 
produce  the  desired  contour,  avoiding  as  far 
as  possible  any  great  excess  of  the  material. 
In  approximal  cavities  a  thin  "  silver-compo  " 
or  celluloid  strip,  with  a  suspicion  of  vaseline 
upon  it,  \^ill  be  found  extremely  useful  in 
shaping  the  filling.  At  this  stage  the  mass 
should  be  left  at  rest  until  it  has  set.  It  is 
finally  polished  ^^-ith  sand-pajier  and  cuttle-fish 
discs,  and  polishing  strips  of  the  same. 

For  reasons  alreaely  stated  it  is  essential  that 
the  cement  shoukl  be  protecteel  from  the  action 
of  the  oral  fluiels  until  it  has  fully  liardencd ; 
this  is  effected  by  the  use  of  the  rubber-dam, 
which  should  be  retained  in  place  for  ten  or 
fifteen  mmutes  after  the  completion  of  the 
fillmg  ;  further  jirotection  may  be  secured  by 
a  coating  of  copal-ether  varnish  or  chloro- 
percha,  or  by  melting  a  little  paraffin  wax  upon 
it.  In  the  so-called  "  hydraulic  "  and  "  sub- 
marine "  cements,  however,  the  formula  is 
deprived  of  a  certain  amount  of  the  water 
necessary  to  satisfy  the  demands  of  the  crystal- 
lizing process.  Such  cements  must  not  be 
kept  dry  whUst  setting,  but  be  allowed  access 
either  to  water  or  the  fluids  of  the  moutli. 

Oxy-phosphates  are  also  employed  to  seal 
medicaments  and  elressings  in  tooth  cavities ; 
when  used  for  this  purpose  more  powder  than 
usual  may  be  mixed  with  the  liquid,  as  a  cement 


so  made  is  less  liarel,  anel  therefore  more  easily 
cut  out  and  removeel.  As  a  lining  for  practically 
all  cavities  of  ^\  hicli  the  filling  is  to  be  completed 
with  gokl  or  amalgam,  it  has  no  ecjual.  The 
method  of  using  it  in  conjunction  with  amalgam 
has  already  been  described  The  cement  may 
be  employed  in  a  somewhat  similar  way  for 
starting  gold  fillings.  A  piece  of  foil  or  a 
cylinder  may  be  packed  into  the  cement  whilst 
it  is  stUl  plastic,  and  the  condensing  of  the  gold 
proceeded  with  when  the  oxy-phospliate  has 
hardened.  The  use  of  the  cement  as  a  lining 
not  only  lessens  the  conduction  of  thermal 
changes  through  the  metal  filling,  but  also  by 
its  firm  adhesion  to  all  the  walls  of  the  cavity 
greatly  strengthens  them  and  the  tooth.  The 
possibility  of  pulp  irritation  may  be  minimized 
by  painting  the  floor  of  the  cavity  \\ith  an 
ethereal  varnish  or  solution  of  gutta-percha. 
Oxy-phosphate  cement  is  also  employeel  very 
largely  for  setting  pieces  of  fixeel  bridge-work, 
crowns,  and  ortlioelontic  appliances,  as  well  as 
for  retaining  jDoreelain  and  gokl  inlays. 

Oxy-chloride  of  Zinc. — Tlie  powder  used  for 
'  these  cements  is  \-ei'y  similar  to  that  already 
'  described,  but  the  liejuid  is  a  solution  of  zinc 
chloride.  It  is  prepared  by  delicpiescing  one 
ounce  of  zinc  chloriele  with  six  elrachms  of 
water.  The  solution  is  allowed  to  stanel  for 
some  days  to  allow  any  residue  to  settle ;  it  is 
then  filtered,  and  bottled,  ready  for  use. 

Oxy-cliloride  cement  possesses  properties 
very  similar  to  those  of  oxy-phosphate.  It 
sets  somewhat  more  rapielly,  however,  anel  is 
more  readily  acteel  upon  by  acids.  0%\-ing  to 
the  caustic  nature  of  zinc  chleiride,  it  is  liable 
to  cause  acute  irritation  of  the  dental  pulp  if 
jjlaced  in  too  close  contact  ^dth  it.  On  the 
other  hand,  in  shallow  cavities  it  serves  as  an 
obtundent  of  sensitive  dentine  by  its  caustic 
i  action  on  the  contents  of  the  tubules.  It 
yields  a  \s-hiter  filling  than  the  oxy-phosphate, 
anel  for  this  reason  is  sometimes  employed 
as  a  Iming  m  staineel  teeth  from  which  the 
discoloration  has  been  partially  removed  by 
bleaching.  In  general  use  it  has  been  displaced 
by  the  preceeling  variety;  it  forms,  however, 
a  most  excellent  root -filling,  being  strongly 
antiseptic — a  property  that  it  retains  for  some 
time  after  setting  (see  Chapter  XXVII). 

Oxy-sulphate  of  Zinc. — Ihis  cement  is  made 
by  mixing  finely  poM-elereel  zinc  oxide  with  a 
saturated  solution  of  zinc  sulphate.  It  forms 
a  white  plastic  mass,  which  sets  somewhat 
quickly,  but  does  not  become  very  hard,  and 
may  be  easily  cut  with  an  excavator.  It  is 
too  soft  and  too  readily  acted  upon  by  moisture 
to  be  employeel  even  as  a  temporary  filling. 
As  a  pidp-capping  material,  however,  it  is  of 
great  service,  its  properties  being  quite  bland 
and  slightly  astringent.     A  small  domed  cap 


400 


of  metal  or  celluloid  is  filled  with  the  plastic 
cement,  with  which  may  be  incorporated  a 
drop  of  one  of  the  essential  oUs,  i.  e.  oil  of  cloves, 
and  is  placed  over  the  exposed  or  nearly  exposed 
pulp ;  a  layer  of  oxy-phosphate  is  then  added, 
and  the  filling  completed  as  desired. 

Fletcher's  artificial  dentine  is  a  cement  of 
the  same  class ;  it  produces  a  harder  mass  than 
the  above,  and  may  be  used  to  seal  temporary 
dressings,  or  as  temporary  fillings  for  a  few- 
weeks  in  sensitive  cavities. 

Its  reputed  formula  is — Poivder :  Zinc  Sul- 
phate, 1  part;  Zinc  Oxide,  2  parts;  calcined, 
ground  and  sifted.  Liquid  :  Gum  Arabic,  grs. 
XX  ;  Water.  5  ss  ;  Sulphite  of  Lime,  gr.  j  (16). 

Oxy-phosphate  of  Copper, — The  cement  that 
is  \'endtd  under  this  name  is  a  modified  oxy- 
phosphate  of  zuic,  and  is  prepared  for  dental 
use  in  the  same  manner  as  that  already  described, 
viz.  by  incorporating  a  po\\der  ^vith  a  liquid. 
It  produces  a  sticky  mass,  jet  black  in  colour, 
which  shows  little  inclination  to  set  when  first 
mixed ;  when  the  process  of  hardening  com- 
mences, however,  the  mass  sets  rather  rapidly, 
even  under  water.  It  adheres  well  to  tooth 
tissue,  and  offers  considerable  resistance  to  the 
action  of  the  oral  fluids.  Its  crushing  stress 
is  less  than  tliat  of  the  oxy-phosphate  and 
sUicate  cements.  The  chief  use  of  oxy-phos- 
phate of  copper  would  seem  to  be  as  a  filling 
material  in  children's  deciduous  teeth,  where  it 
endures  sufficiently  long  to  serve  its  purpose. 
An  analysis  of  the  powder  of  one  of  these 
cements  showed  it  to  be  composed  of  zinc  oxide, 
cojjper  oxide,  and  an  appreciable  amount  of 
the  oxides  of  both  cobalt  and  iron.  The  liquid 
is  lihosphoric  acid  contaimng  a  little  zinc  oxide 
in  .solution. 

Silicious  Cements. — The  distinguishing  feature 
of  these  cements  when  compared  with  those 
already  mentioned  is  their  greater  degree  of 
translucency,  and  consequent  closer  resemblance 
to  the  enamel  of  the  natural  tooth. 

The  original  silicious  cement  was  introduced 
by  Fletcher  of  Warrington  in  1878.  From  his 
Letters  Patent  it  would  appear  that  the  powder 
consisted  of  hydrate  of  alumina,  heavy  oxide 
of  zinc  or  magnesia,  and  basic  silicate  of  zinc  ; 
and  the  liquid,  of  phosphate  of  alumina  dissolved 
in  phosphoric  acid.  This  cement,  however, 
proved  a  failure  and  was  ^^-ithdrawn  from  the 
market,  and  the  patent  lapsed. 

In  1904  Steenbock  filed  a  new  patent  for  an 
improved  form  of  this  filling  material,  the 
powder  of  which  was  composed  of  beryllium 
nitrate  and  sodium  silicate,  and  the  liquid  of 
a  nearly  saturated  solution  of  aluminium,  zinc, 
and  strontium  pho.sphates  in  52  per  cent  ortho- 
phosphoric  acid.  There  are  now  a  large  number 
of  these  so-caLIed  silicate  cements  upon  the 
market    vended    under    various    trade    names. 


There  is  hardly  a  single  make,  however,  that 
has  not  been  modified  since  its  first  appearance  ; 
indeed,  it  would  seem  that  the  compound  is  still 
in  an  experimental  stage,  and  hence  it  is  only 
possible  to  -wTite  of  it  in  general  terms. 

The  following  formula  also  has  been  regis- 
tered— 

Four  to  6  parts  of  finely  ground  aluminium 
silicate  are  mixed  with  8  parts  of  a  fused,  cooled, 
and  finely  ground  mixture  of  1  part  of  calcium 
oxide,  2  parts  of  silicon  anhydride,  and  1 
part  of  aluminium  oxide.  The  liquid  is  a 
solution  of  phosphoric  acid  of  a  specific  gravity 
of  r5,  and  containing  150  grammes  of  aluminium 
oxide  to  the  litre.  Colouring  ingredients  are 
added  as  desired. 

The  possible  chemical  reactions  that  take 
place  when  these  cements  harden  are  difficult 
to  determine.  Dreschfeld  (10)  has  suggested 
the  follo'O'ing  as  being  approximately  the  for- 
mulae of  two  different  varieties — 

(1)  12CaSi03  +  UBeSiOa  +  13  AL,  (POJ., 
+  xSiOo  +  xH,0. 

(2)  eCaSiOg  +  4BeSi03  -f  13  Al.,  (F0,)„  -f 
xSiO,  +  xH,0. 

Both  of  these  cements  contain,  as  wUl  be 
seen,  beryllium,  and  it  is  claimed  that  its 
presence  adds  greatly  to  the  insolubility  of  the 
filling.  On  the  other  hand,  varieties  from  which 
this  substance  is  absent  appear  to  possess  an 
equal  resistance  to  the  action  of  the  oral  fluids. 

It  is  not  at  present  known  jjrecisely  what  is 
the  reaction  that  occurs  to  cause  the  cementation 
of  the  mass — whether  it  is  due  to  "  the  gelatin- 
izing of  the  finely  divided  silicates  through  the 
action  of  the  acid"  (11);  or  whether  "the 
silicates  are  merely  held  together  by  a  basic 
pliosj)hate  "  formed  by  the  action  of  the 
phosphoric  acid  on  the  calcium  present.  If  the 
latter  is  true,  these  cements  are  but  modified 
oxy-phos[)liates  (1). 

In  mixing  these  cements  absolute  cleanluiess 
is  essential,  and  it  is  ad\'isable  to  use  an  agate 
or  bone  spatula,  as  steel  or  nickel  is  liable  to 
affect  the  colour.  The  incorporation  of  the 
powder  v,-ith  the  liquid  must  be  quite  complete, 
and  shoidd  be  carried  to  a  stage  resembling 
slightly  softened  wax.  It  is  then  conveyed  to 
the  cavity  by  suitable  pluggers,  made  of  agate, 
ivory,  tortoise-sheU,  or  tantalum,  and  rapidly 
packed  into  place  in  small  pieces.  It  is  most 
important  to  keep  the  filliiig  absolutely  dry 
until  it  has  set ;  this  is  secured  by  the  use  of  the 
rubber-dam.  As  with  other  cements,  setting 
can  be  hastened  by  the  application  of  heat, 
such  as  may  be  obtained  by  a  hot-air  syringe, 
the  average  time  to  allow  being  about  fifteen 
minutes.  With  care  and  skill,  cavities  can  be 
filled  so  as  to  demand  a  minimum  amount  of 


401 


trimming  of  the  filling  after  it  has  hardened. 
In  approximal  cavities  a  thin  celluloid  strip 
contributes  to  this  end,  jiroducing  a  surface 
that  is  the  best  obtainaljle.  As  soon  as  the 
cavity  is  full,  it  is  always  advisable  \\'ith  all 
cement  fillings  to  allow  the  mass  to  harden 
before  disking  or  burnishing  its  surface — in 
other  words,  not  to  interfere  with  its  crystal- 
lization. It  has  been  suggested  that  this  rule 
should  be  disregarded  with  silicious  cements, 
and  that  the  sxu'face  should  be  worked  wp  with 
agate  burnishers  and  a  little  vaselme  during 
the  setting,  but  there  seem  to  be  no  just  grounds 
for  such  a  procedure ;  a  perfect  surface  can  be 
obtained  in  the  manner  already  described,  or 
where  this  is  impossible,  by  the  finest  of  cuttle- 
fish discs  with  a  little  paraffin  wax.  For  further 
protection  from  moisture  a  wafer  of  paraffin 
wax  may  be  sweated  over  the  entire  surface 
of  the  filluig  before  the  removal  of  the  rubber- 
dam. 

The  chief  advantages  of  sUicious  cements  as 
compared  ^vith  oxy-phosphates  are  their  greater 
translucency,  and  resistance  to  the  action  of 
the  oral  fluids ;  they  are  also  stronger.  Their 
translucency  is  dependent  upon  the  presence 
of  moisture.  They  lack  the  adhesiveness  of 
oxy-phosphates,  and  in  many  instances  prove 
very  irritating  if  placed  in  too  close  proximity 
to  the  dental  pulp.  For  retention  the  cavity 
should  be  slightly  undercut,  and  lined  \^'ith 
the  more  adhesive  oxy-phosphates,  as  suggested 
when  describmg  the  methods  of  inserting  dental 
amalgam,  and  the  edges  should  be  as  square 
as  possible. 

These  fillings  have  not  yet  had  a  sufficiently 
long  trial  to  prove  their  real  merits.  Many 
show  a  porous  surface  after  a  few  months,  and 
discolour ;  this  may  be  due  to  faulty  manipida- 
tion,  as  others  in  the  same  mouth  may  wear 
well.  They  are  certainly  not  insoluble,  but  in 
this  respect  are  far  superior  to  the  other  osteo- 
plastic cements.  Their  appropriate  place  is 
in  small  cavities,  not  involving  the  incisal 
margin,  in  anterior  teeth,  and  occasionally  in 
compound  cavities  in  premolars.  For  large 
restorations  in  incisors  they  are  far  inferior  to 
porcelain  inlays. 

3.  GUTTA-PERCHA  COMPOUNDS 

Gutta-percha. — Gutta-percha  is  the  inspissated 
juice  obtained  from  incisions  made  through 
the  bark  of  trees  belonging  to  the  order,  "  Sapo- 
taceae  ".  Its  chief  source  is  the  "  Isonandra 
Gutta  ",  which  is  found  in  the  East,  and  particu- 
larly in  the  Malay  Archipelago.  Crude  gutta- 
percha consists  of  a  hydro-carbon  possessing  the 
formula  C,qH,,.,  ;  certain  resins,  of  which  one  is 
yellow  and  kno^\^l  as  fluavile  (CViHi-^O.,),  and 
another  white  called  albane   (CnjHujO) ;  and  a 


variable  component  named  guttane ;  together 
with  foreign  matters,  such  as  sawdust,  earth, 
etc.  The  essential  constituent  is  the  hydro- 
carbon, ^^■hich  represents  the  pure  gutta,  whilst 
the  resins  represent  compounds  resulting  from 
oxidation.  The  crude  samples  vary  much  in 
colour,  from  dark  brown  to  ^vhitisll-yello^\^ 
whilst  the  amount  and  the  quality  of  the  yield 
depend  uiDon  the  condition  of  the  trees  and  the 
time  of  year  it  is  tapped.  The  amount  of  gutta 
in  different  samples  varies  from  30  to  85  jaer 
cent;  of  resins  from  11  to  8  per  cent;  foreign 
bodies  from  2  to  5  per  cent ;  ^vhilst  the  amount 
of  water  present  depends  partly  upon  the  length 
of  time  that  has  elapsed  since  the  juice  was 
collected.  To  purify  it,  the  blocks  as  imported 
are  cut  into  slices  by  machinery,  and  washed 
in  hot  water ;  when  soft  enough  the  masses  are 
passed  through  a  machine  that  shreds  them 
into  smaller  particles;  the.se  are  again  washed 
in  water,  when  the  heavier  foreign  particles 
sink  to  the  bottom  of  the  trough,  and 
the  lighter  gutta-percha  floats  and  is  removed. 
It  is  next  heated  by  steam,  and  worked 
up,  whilst  soft,  into  blocks  of  required  size. 
It  is  of  importance  that  the  crude  samples 
should  be  purified  as  soon  as  possible  ;  otherwise 
oxidation  occurs  and  deterioration  ensues. 

Pure  gutta-percha  is  white  in  colour,  hard, 
and  tough  when  cold,  but  rendered  soft  and 
pliable  when  heated.  It  is  soluble  in  benzene, 
chloroform,  and  bisulphide  of  carbon,  and 
partially  in  ether  and  the  essential  oils.  It  is 
insoluble  in  water,  dilute  acids  and  alkalies, 
and  in  alcohol.  Wlien  incinerated  pure  gutta- 
percha leaves  about  one  per  cent  of  a.sh  only. 

The  chief  uses  of  gutta-percha  in  dental 
practice  are  :  as  a  filling-material ;  to  form  root- 
canal  fillings ;  for  taking  impressions ;  as  a 
soft  lining  for  lower  dentures  ;  for  setting  crowns 
and  bridges.  For  these  various  purposes  other 
substances  are  added  with  the  object  of  im- 
j^arting  special  properties. 

Gutta-percha  as  a  Filling-material. — The  chief 
advantages  of  gutta-percha  as  a  fillmg- material 
are  :  when  softened  it  is  easily  inserted ;  it  is 
a  very  poor  conductor  of  thermal  changes ;  it 
is  compatible  \\-ith  the  tooth  substance ;  it  is 
insoluble  in  the  oral  fluids ;  and  it  protects  the 
tooth  against  recurrent  caries.  The  chief  dis- 
advantage is  that  it  is  the  least  hard  and 
rigid  of  any  filling-material ;  its  use  is  therefore 
contra-indicated  in  situations  where  it  is  liable 
to  be  subjected  to  much  mechanical  stress 
durmg  mastication;  some  makes  tend  to  swell 
and  are  to  a  certain  extent  f)orous,  becoming 
foul  after  being  in  use  for  some  time. 

To  impart  hardness  and  thus  improve  its 
wearing  properties,  zinc  oxide  and  finely  ground 
silica  are  added ;  this  is  accomplished  by  in- 
corporating a  little  at  a  time  and  thoroughly 


402 


kxieading  it  into  the  softened  gutta.  The  forms 
of  gutta-percha  known  as  low,  medium,  and 
high  heat,  are  produced  by  varying  the  amount 
of  zinc  oxide ;  thus,  the  low  heat  contains  4  j)arts 
of  zinc  oxide  to  1  of  gutta-percha  and  is 
softened  at  a  temperature  below  200°  F. ;  the 
medium  contains  6  to  1  and  softens  at  205°  F. ; 
whilst  the  high  heat  contains  just  sufficient 
gutta-percha  to  bind  the  particles  of  zinc  oxide 
together  and  softens  at  about  220°  F.  (8). 
Whilst  the  addition  of  such  substances  as  zinc 
oxide  and  sUica  undoubtedly  imparts  wear- 
resistmg  jjroperties  to  tlie  filling,  it  at  the  same 
time  impairs  one  of  its  most  desirable  qualities, 
viz.  toughness.  It  therefore  seems  desirable  to 
limit  the  amount  of  these  substances.  Rushton 
recommends  the  following  :  Pure  gutta,  50 
parts ;  furely  levigated  silica,  30  parts ;  oxide 
of  zinc,  20  jmrts  (22,  p.  116).  The  zinc  oxide 
and  silica  are  mixed  together  and  worked  into 
the  gutta,  which  has  been  gradually  heated, 
a  little  at  a  time. 

Another  form  of  "  Permanent  "  gutta-percha 
is  prepared  in  the  follo-sving  manner.  The 
crude  gutta  is  thoroughly  washed  in  hot  water, 
and  as  much  du't  and  other  foreign  particles 
as  possible  are  removed.  It  is  then  dried  and 
made  uj)  into  small  pellets,  -which  are  enclosed 
in  Imen  bags  and  immersed  in  cUoroform.  The 
gutta  is  dissolved  by  the  chloroform,  ^N'hilst 
extraneous  matters  are  retained  inside  the  bags. 
The  solution  of  chloro-percha  is  collected  and 
placed  in  a  vessel  with  a  stop-cock  at  its  lower 
end,  through  which  its  contents  may  be  drawn 
off.  By  the  addition  of  a  little  water  a  small 
portion  of  the  gutta-percha  is  precipitated  ;  this 
floats  to  the  top  and  carries  ^\'ith  it  such  foreign 
particles  as  remain  in  the  solution.  The  vessel 
is  then  emptied  by  way  of  the  stop-cock,  the 
chloroform  is  driven  off  by  heat,  and  the  gutta- 
percha thus  recovered.  After  drying  and  heat- 
ing, 20  per  cent,  of  finely  ground  \\'hite  silica 
is  added  (22,  p.  113).  Rushton  suggests  that- 
the  value  of  a  filling-material  so  prepared  depends 
very  much  upon  the  quality  of  the  crude  sample 
of  gutta-percha  originally  taken,  inasmuch  as 
the  method  of  preparation  fails  to  eliminate 
the  resins  present ;  these,  however,  may  be  got 
rid  of  by  treating  a  solution  of  gutta-percha 
with  spirit,  \^hicli  dissolves  out  the  resins  and 
throws  down  the  gutta. 

The  so-called  pink  base-plate  gutta-percha 
contains  sulphide  of  mercury  (vermilion)  in 
addition  to  zinc  oxide. 

Gutta-percha  deteriorates  after  long  exposure 
to  light,  and  should  therefore  be  kept  either 
wrapped  in  metal  foU,  or  in  boxes  or  bottles 
that  are  impervious  to  light.  In  softening 
gutta-percha  care  is  needed  to  avoid  over- 
heating, as  the  material  is  easily  burnt  and 
oxidized,  its  properties  being  thereby  ruined. 


Softening  is  best  effected  by  placing  the  gutta- 
percha on  a  slab  of  mica  or  soap-stone,  and 
applying  heat  to  the  under-surface  of  the  slab 
from  a  sjjirit  lamp,  any  actual  contact  with 
a  naked  flame  being  prevented  by  these 
means. 

The  cavity  for  the  reception  of  "  permanent  " 
gutta-f)ercha  should  be  prepared  with  perfectly 
even,  square  edges,  and  with,  some  degree  of 
undercut.  Anything  in  the  nature  of  a  feather 
edge  in  the  completed  filling  is  to  be  avoided. 
A  little  oil  of  cajuput  should  be  smeartd  over 
the  cavity  walls ;  this  assists  greatly  in  producing 
a  \\atertight  plug.  Small  pieces  should  be 
used,  and  carefully  packed  into  place  with  a 
nearly  cold  instrument.  The  head  of  the 
plugger  should  be  round,  slightly  tapered,  and 
^^^th  a  smooth  flat  face.  Every  eflort  should 
be  made  to  complete  the  filling  in  such  a  manner 
as  to  avoid  as  far  as  possible  the  necessity  to 
trim  it  afterwards ;  such  amount  of  trimming 
as  may  be  requu-ed  is  best  effected,  after  the 
filling  has  hardened,  with  a  small,  very  sharp 
knife.  The  whole  surface  should  then  be 
burnished  with  an  instrument  slightly  warmed. 

The  so-called  "  Temporary  "  gutta-percha  is 
composed  of  gutta-percha,  white  wax.  Burgundy 
pitch,  zinc  oxide,  chalk,  and  often  some  colour- 
ing matter.  It  is  of  great  service  as  a  temporary 
filling-material,  for  sealing  medicaments  in  a 
tooth  cavity,  for  preserving  and  promoting 
space  between  two  teeth  preparatory  to  filling, 
and  for  filluig  root-canals.  As  might  be  in- 
ferred from  its  composition,  it  softens  at  a 
much  lower  temperature  than  the  more  perma- 
nent variety  described  above,  and  is  more 
easily  inserted  and  removed ;  further,  it  is 
somewhat  adhesive.  It  is  quickly  worn  away, 
however,  if  placed  in  a  position  in  \\hicli  it  is 
subjected  to  attrition,  and  is  decidedly  porous. 

'M.F.  H. 

BIBLIOGRAPHY 

(1)  Ames,  W.     Dental  Cosmos,  1909,  Vol.  LI,  p.  463. 

(2)  Badcoce.  J.  H.     Trans.  Odont.  Soc,  1896-7,  Vol. 

XXIX,  p.  112. 

(3)  Baldwin,  H.     Trans.   Odont.  Soc,   1896-7,  Vol. 

XXIX,  p.  93. 

(4)  Black,  G.  V.     Operative  Dentistry,  Vol.  II. 

(5)  Black,     G.     V.      Dental     Cosmos,     1895,     Vol. 

XXXVII,  p.  558. 

(6)  Boyd-Wallls,  C.  J.     Trans.  Odont.  Soc.,  1896-7, 

Vol.  XXIX,  p.  127. 

(7)  Brislee,  F.  J.     Dental  Record,  1906,  Vol.  XXVI, 

p.  53. 

(8)  BtjRCHARD,    H.    H.     Kirk's    Operative   Dentistry, 

p.  240. 

(9)  CoLYEB,  J.  F.     Dental  Surgery,  p.  456. 

(10)  Dreschfeld,    H.    T.     Brit.    Dent.    Jour.,    1907, 

Vol.  XXVIII,  p.  1065. 

(11)  Dunning,  W.  B.     Dental  Cosmos,  1909,  Vol.  LI, 

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(12)  Essio,  C.  J.  Dental  Metallurgy,  p.  241. 

(13)  Fenchel,  a.  Dental  Cosmos,  1908,  Vol.  L,  p.  I. 

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403 


(15)  Flagg,  J.  F.     Plastic  Fillings,  p.  156. 

(16)  Fletcher,  T.     Dental  Metallurgy. 

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(18)  Johnson,  C.  N.     Principles  and  Practice  of  Filling 

Teeth,  p.  238. 

(19)  KiRBY,  A.     Trans.  Odont.  Soc,  1875-6,  Vol.  VIII, 

p.  7. 

(20)  KiRE,  E.  C.     Operative  Dentistry,  1898,  p.  226. 


(21)  Parfitt,  J.  B.     Trans^  Odont.  Soc,  1902-3,  Vol. 

XXXV,  p.  65. 

(22)  RusHTON,  W.     Trans.  Odont.  Soc.   1897-S,  Vol. 

XXX. 

(23)  Tomes,  C.   S.     Trans.  Odont.  Soc,    1894-5,  Vol. 

XXVII,  p.  56. 

(24)  TuLLOCH,   A.     Trans.   Odont.   Soc,    1902-3,   Vol. 

XXXV,  p.  210. 


CHAPTEIi   XXIV 


PORCELAIN  INLAYS 


THE    VALUE  OF  PORCELAIN    AS    A   FILLING- 
MATERIAL. 

The  manipulation  of  a  material  and  its  value 
for  the  purposes  of  filliiig  teeth  depend  upon 
its  physical  and  chemical  properties ;  hence 
these  must  be  considered  before  questions  of 
operative  procedure  are  dealt  with.  The  most 
useful  way  of  doing  this  is  to  see  how  far  it 
fulfils  the  requirements  of  what  may  be  called 
the  "  ideal  filling- material  ",  and  also  in  what 
respects  it  falls  short  of  this  ideal. 

The  qualities  required  in  an  ideal  filling- 
material  are — 

(1)  It  must  be  free  from  changes  of  form, 
bulk,  or  colour  under  the  influence  of  any 
agencies  that  may  be  brought  to  bear  upon  it 
in  the  mouth,  whether  these  be  chemical  or 
physical,  inherent  in  its  own  substance,  or 
external  to  it. 

(2)  It  must  be  innocent  of  any  harmful 
action  on  tooth  substance,  pulf),  neighbouring 
teeth,  oral  mucous  membrane,  or  the  general 
health  of  the  patient. 

(3)  It  should  be  pleasing  in  appearance  ;  this 
can  only  be  the  case  if  the  filling  harmonizes 
so  well  with  its  surroundings,  that  the  casual 
observer  would  not  notice  it. 

(4)  It  should  be  easy  to  manipulate. 

In  considering  the  properties  of  a  porcelain 
inlay  it  must  be  remembered  that  the  cement 
lute  forms  an  essential  part  of  it ;  in  fact,  it 
would  not  be  altogether  incorrect  to  describe 
it  as  a  cement  filling  \\-ith  a  working  face  of 
porcelain. 

Witli  regard  to  the  first  requirement,  freedom 
from  secular  change,  the  porcelain  part  of  the 
filling  almost  comes  up  to  the  ideal  standard. 
It  does  not  expand  or  contract,  nor  does  it 
midergo  any  chemical  change,  with  the  excep- 
tion of  a  slight  roughening  or  etching  of  the 
surface,  which  sometimes  occurs  in  certain  low- 
fusing  porcelains,  and  causes  a  deterioration  of 
colour  from  deposit  of  stain. 

The  chief  thing  to  be  feared  is  the  impact 
of  a  heavy  bite.  Porcelain  nuist  be  classed  as 
a  distinctly  brittle  substance,  and  if  sharp  edges 
of  it  are  exposed  to  heavy  jjressure  they  wUl 
almost  certainly  be  chipped.  In  the  mass, 
however,  porcelain  has  considerable  strength ; 
Le  Cron  found  its  resistance  to  crushing  to  vary 


404 


from  seven  to  twenty  tons  to  the  square  inch, 
according  to  the  kind  of  porcelain,  so  that  there 
need  be  little  fear  that  a  well-made  inlay  wUl 
be  actually  broken. 

In  spite  of  experiments  that  seem  to  prove 
the  contrary,  it  may  be  said  that,  for  all 
practical  purposes,  the  cement  lute  neither 
expands  nor  contracts ;  it  is,  moreover,  pro- 
tected by  the  porcelain  from  being  worn  away 
by  the  tooth-brush  and  by  mastication — 
agencies  that  are  very  destructive  to  plain 
cement  fillings.  At  the  joint,  however,  it  is 
exposed  to  the  chemical  action  of  the  saliva 
and  substances  dissolved  in  it,  and  for  this 
reason  many  dentists,  when  fu'st  using  porcelain 
inlays,  feared  that  they  would  soon  drop  out 
in  consequence  of  the  solution  of  the  cement 
lute.  So  far  from  this  being  the  case,  ex- 
perience has  showTi  that  well-fitted  porcelain 
inlays  last  remarkably  well,  and  have  good 
claim  to  rank  with  gold  and  amalgam  as  per- 
manent fiUings  (3).  The  explanation  probably 
is  that  the  solution  of  the  cement,  although  it 
may  possibly  go  on  fairly  fast  at  first,  quickly 
comes  to  a  standstill.  For  a  solid  to  dissolve 
in  a  liquid  there  nuist  be  a  more  or  less  con- 
tinuous removal  of  the  saturated  solution,  so 
that  the  solid  may  be  exposed  to  the  action  of 
a  fresh  portion  of  liquid.  In  the  case  of  a  well- 
fitting  inlay,  the  cement  presents  only  a  thin 
edge  to  the  action  of  the  saliva ;  after  solution 
has  gone  on  for  a  short  time,  the  exposed  surface 
of  the  cement  will  lie  at  the  bottom  of  a  deep 
and  narrow  chink  between  the  enamel  on  the 
one  hand  and  the  porcelain  on  the  other ;  this 
chink  will  fill  up  with  insoluble  j)articles  and 
greasy  materials  from  the  food,  so  that  the 
saturated  solution  will  gradually  stagnate  at 
the  surface  of  the  cement,  and  solution  wUl 
either  cease  altogether,  or  proceed  with  extreme 
slowness. 

The  second  quality,  freedom  from,  harmful 
action,  is  also  possessed  by  porcelain  inlays  in  a 
high  degree  :  to  the  tooth  substance  and  pulp 
they  behave  like  cement,  which  years  of  experi- 
ence have  shown  to  be  one  of  the  least  u'ritating 
of  fillings ;  the  porcelain  surface,  from  its 
chemical  nature,  is  quite  incapable  of  any 
injurious  action  on  living  tissues  and  also  has 
the  great  advantage  of  being  highly  glazed,  and 
as  this  glaze  is  permanent,  porcelain  ranks  with 


405 


gold  as  one  of  the  most  cleanly  materials  for 
interstitial  fillings. 

In  the  matter  of  the  third  quality,  pleasing 
appearance,  jjorcelain  leaves  very  little  to  be 
desired.  Natural  teeth  are  translucent,  and 
their  colour  depends  very  much  on  the  light  that 
comes  to  the  eye  from  the  dentme  that  under- 
lies the  relatively  transparent  enamel.  Porce- 
lain bodies  have  much  the  same  translucency  as 
the  natural  teeth,  and  with  care  any  natural 
colour  can  be  very  exactly  matched.  The 
chief  difficulty  m  the  matter  of  colour  arises 
from  the  opacity  of  the  cement  lute.  The 
main  lighting  of  the  teeth  is  from  the  front  and 
above  ;  if  an  opaque  layer  of  cement  intercepts 
part  of  the  light,  the  portion  of  material  nearer 
the  source  of  light,  whether  it  be  tooth  or 
porcelain,  will  send  back  to  the  eye  more  than 
its  share  of  light,  in  other  words  it  will  appear 
lighter  in  colour,  and  the  other  portion  con- 
versely w  ill  appear  darker.  If  the  source  of  light 
be  shifted,  the  colours  of  tooth  and  porcelain 
will  alter  relatively  to  one  another,  so  that 
\\hLle  it  is  always  possible  to  match  the  inlay  for 
one  particular  incidence  of  light,  it  is,  as  a  rule, 
not  possible  to  make  it  look  equally  «ell  under 
different  conditions  of  lighting.  The  difficulty 
is  at  a  minimum  when  the  oj)aque  layer  is 
parallel  to  the  rays  of  incident  light. 

With  regard  to  the  fourth  requirement, 
facility  of  manipulation,  it  must  be  at  once 
confessed  that,  from  the  of)erator's  point  of 
view,  porcelain  fillings  stand  at  the  bottom  of 
the  list.  Besides  the  difficulty  of  fitting  the 
porcelain,  tlie  fact  that  it  is  an  inlay  and  nnist 
be  inserted  all  in  one  piece  necessitates  a  great 
deal  of  separation  and  cavity  preparation  that 
would  not  be  required  for  gold  or  amalgam.  To 
the  patient  the  making  of  an  inlay  is  not  so 
tedious  as  many  other  operations,  as  so  much 
of  the  work  is  done  out  of  the  moutli. 


CAVITY  PREPARATION  FOR  PORCELAIN 
INLAYS 

The  principles  underlying  the  preparation  of 
cavities  may  be  divided  into  two  classes  :  those 
that  apply  equally  to  aU  permanent  fillings,  and 
those  that  depend  upon  the  special  properties 
of  the  material  in  hand. 

The  main  pruiciples  of  the  first  class  are — ■ 

(a)  The  cavity  margin  should  be  extended 
until  it  is  formed  entirely  of  hard  translucent 
enamel  of  perfect  structure,  without  any  chalky 
patches  of  decalcification.  -Tlie  slope  of  the 
cut  surface  from  the  outside  Aovn\  to  the 
dentine  should  correspond  \\ith  the  direction 
of  the  natural  cleavage  of  the  enamel,  that  is 
with  the  slope  of  the  prisms. 

(ft)  All  carious  dentine  should   be  removed, 


the  practical  sign  of  caries  being  decalcification 
and  consequent  softenhig  of  the  matrix. 

(c)  The  pulp  must  be  in  such  a  condition  that 
it  is  likely  to  remain  for  an  indefinite  time  with- 
out giving  trouble  ;  that  is  to  say,  it  should  either 
be  healthy  and  well  protected,  or  else  destroyed 
and  its  place  taken  by  a  satisfactory  root- 
filling. 

The  special  qualities  of  porcelain  bearing  on 
cavity  prej)aration  are — 

(a)  The  fact  that  the  inlay  has  to  be  made 
out  of  the  mouth  and  then  conveyed  to  the 
cavity. 

(b)  Its  strength  in  bulk,  and  weakness  m 
thin  flakes  and  sharp  margins. 

(c)  Its  lack  of  any  real  acUiesion  to  the 
cement. 

{d)  Its  close  correspondence  with  the  colour 
of  the  natural  teeth,  and  lack  of  any  injurious 
action,  especially  heat  conductivity. 

To  commence  with,  there  must  be  good  access 
to  the  cavity  in  order  that  the  impression  may 
be  secured  and  the  inlay  inserted,  the  latter 
often  requiring  more  room  than  the  former. 
Access  may  be  obtamed  by  separation  or  by 
cavity  extension,  or  a  combination  of  the  two. 
The  teeth  can  be  separated  by  any  of  the  ordinaiy 
methods.  The  most  useful  plan  is  to  let  the 
patient  wedge  them  apart  with  three  or  four 
thicknesses  of  tape,  and  at  the  time  of  the  opera- 
tion to  apply  a  Perry  separator  gently  so  as  to 
steady  the  otherwise  loose  and  tender  teeth, 
and  mcidentally  obtain  some  extra  space.  If 
access  is  still  too  restricted,  the  cavity  may  be 
extended  in  whatever  direction  gives  the  best 
result,  the  satisfactory  colour  of  porcelain  allow- 
ing it  to  be  carried  over  the  front  surface  of  the 
tooth,  if  need  be. 

The  cavity  itself  must  be  free  from  undercuts, 
as  these  would  make  the  taking  of  a  con-ect 
impression  impossiljle.  If  undercuts  exist  they 
must  be  obliterated,  either  by  filling  them  up 
with  cement,  or  by  cutting  away  the  over- 
hanging edges. 

In  the  preparation  of  the  cavity  special  care 
must  be  taken  to  ensure  the  strength  of  the 
porcelain,  both  in  the  mass  and  at  the  margins, 
and  also  adequate  retention  for  it ;  it  is  also 
very  desirable  that  the  cavity  shall  have  such 
a  sliape  both  in  marginal  outline  and  in  cross- 
section,  that  there  shall  be  no  possible  doubt 
as  to  the  exact  way  the  inlay  shall  go  into 
place. 

If  the  cross-section  of  a  well-prepared  cavity 
for  a  pinless  inlay  of  simple  shape  be  studied, 
it  will  be  seen  that — 

(a)  It  is  of  reasonable  depth.  This  is  neces- 
sary in  order  to  give  strength  to  the  inlay,  and 
also  to  allow  of  definite  grooving  of  its  sides  for 
purposes  of  retention.  No  definite  nile  can  be 
given  as  to  how  thick  the  porcelain  must  be. 


406 


as  the  thickness  will  bear  some  sort  of  relation 
to  its  surface  area ;  it  must  be  neither  so  thick 
as  to  endanger  the  pulp  in  the  preparation  of 


Fig.  466. — Diagrammatic  section  of  inlay  cemented 
in  tooth. 

the  cavity,  nor  so  thin  as  to  constitute  a  mere 
veneer. 

(b)  The    sides   slope    steeply    from   the    free 


A 


(' 


B 

Fio.   467. 
<A)   Simple  approximal  cavity  in  front  tooth. 

(B)  Cross-section  of  same,  with  inlay  in  position. 

(C)  Longitudinal    section    of    same,    with    inlay    in 

position. 

surface  to  the  floor,  and  meet  both  as  nearly  as 
possible  at  right  angles ;  this  does  not  neces- 
sarily mean  tliat  the  opposite  sides  are  parallel. 


of  the  porcelam  and  slightly  undercutting  the 
correspondmg  parts  of  the  cavity.  The  inlay 
Ls  then  independent  of  any  mere  adhesion,  but 
is  keyed  in  by  the  mass  of  cement  that  occupies 


A  B 

Fig.  469. 

(A)  Cavity  in  premolar  mvolving  cusp. 

(B)  Inlay  for  same. 

the  grooves,  and  can  only  come  out  if  this  mass 
is  crushed  or  sheared  across. 

It  will  be  seen  that  all  these  requirements 
are  satisfied  by  a  Ball's  inlay,  which  may  be 


A  B  C 

Fig.   468. 

(A)  Approximal  cavity  in  front  tooth,  opening  on  labial 

sm'face. 
<B)  Cross-section  of  same,  with  inlay  in  position. 
(C)  Longitudinal  section  of  same,  with  inlay  in  position. 

because  the  surface  of  the  tooth  is  not  fiat  but 
■curved.  This  shape  gives  the  maximum  edge 
strength  to  the  inlay,  and  also  allows  exceUent 
anchorage  to  be  obtained  by  groovmg  the  sides 


B  .\ 

Fig.  470. 

(A)  "  Isthmus  "  cavity  in  lower  molar. 

(B)  Inlay  for  same. 

taken  as  a  type  of  all  those  that  depend  for 
retention  upon  their  shape  and  not  on  a  post 
or  staple.  From  this  type  there  will  be  endless 
variations  in  such  matters  as  marginal  outline, 
proportion  between  depth  and  width,  curva- 
ture of  surface  and  floor,  and  inclination  of 
sides. 

Sometimes  complicated  shapes  occur, 
which  may  be  looked  upon  as  two  or  more 
simple  cavities  jomed  into  one ;  such  are  the 
combmation  crown  and  approximal  cavities 
of  molars  and  premolars,  forming  "  isthmus  ", 
"  saddle-shaped  ",  and  "  dovetail  "  cavities. 
These  all  differ  from  the  simple  type  rather 
in  their  extent  than  in  the  principles  of  their 
preparation. 

In  aO  cases  the  cavity  must,  if  possible,  be 

so  shaped  that  dislodgement  is  resisted  by 

some  definite  keying  of  the  porcelain  into 

the   tooth  substance.     In  "  saddle-shaped  " 

cavities,  involving  the  medial,  crown,  and  distal 

aspects  of  a   molar  or  premolar,  the   natural 

shape  affords  ideal  retention  and  resistance  to 

dislodgement  by  the  bite. 


407 


As  good  a  result  is  also  obtained  in  "  isthmus  " 
and  "  dovetail  "  cavities,  whose  shape  wUl  only 
allow  the  insertion  or  withdrawal  of  tlie  inlay 
from  the  cro«ii  surface. 

In  cavities  exposed  to  the  bite,  and  in  wliich 
no  dovetail  or  post  can  be  arranged,  the  best 
plan  is  to  make  the  floor  and  wall  meet  at  a 


B 
Fig.  471. 

(A)  Approximal  cavity  in  canine,  opening  on  to  lingual 

surface. 

(B)  Transverse    section    of    san^e    tootli    witli    inlay    in 

position. 

(C)  Longitudinal    section   of   same    tooth    with    inlay    in 

position. 

sharp  angle  at  the  point  opposite  the  direction 
of  the  prevailing  force.  In  such  a  position  as 
the  cervical  part  of  a  premolar  or  molar,  or  the 
labial  margm  of  a  front  tooth  cavity  that  ojJens 
on  the  lingual  surface,  the  angle  may  for  a  short 
distance  be  less  than  a  right  angle,  so  that  the 
pressure  tends  rather  to  di'ive  the  uilay  further 
into  the  cavity  than  to  dislodge  it. 

A  different  mode  of  preparation  is  often,  al- 
though not  always,  adojited,  wlien  a  inn,  post, 
or  staple  is  used  for  the  retention  of  the  inlay. 
The  more  the  retention  depends  on  the  metal 


results  in  actual  practice,  or  by  experience  of 
the  analogous  arrangement  in  the  ordinary  pin 
teeth  used  in  j)rosthetic  work. 

In  preparing  a  cavity  for  this  kmd  of  reten- 
tion, it  is  necessary  to  decide  on  the  position, 
du-ection,  and  size  of  the  hole  that  is  to  receive 
the    post.     In   a   dead   tooth    this    is   an   easy 
matter,  as  a  stout  post,  anything  up  to  pin  size, 
in   an   enlarged   root-canal    will    give   all   the 
holdfast  neces.sary.     In  living  teeth  the  holes 
nuist  of  necessity  be  small,  as  they  have  to  be 
uell  internal  to  the  enamel  and  at  the  same 
time  must  not  endanger  the  pulp  :  practically, 
nothing  larger  or  longer  than  an  artificial  tooth 
pin  can  be  used. 

The  direction  must  be  such  as  not  to  inter- 
fere with  the  insertion  of  the  inlay.  The 
position  of  the  hole  should  be  so  chosen  that  the 
force  that  tends  to  dislodge  the  porcelain  will  be 
resisted  by  the  whole  tensile  strength  of  the  pin, 
in  other  words,  it  must  tend  to  pull  the  pin  out 
and  not  merely  to  bend  it ;  thus  in  the  case  of 


Fig.  472. 

(A)  Canine  tooth  requiring  restoration  of  tip. 

(B)  Porcelain  tip  for  same  showing  retention  posts. 

holdfast,  the  less  need  there  is  to  have  the  mass 
of  porcelain  actually  keyed  into  the  cavity ;  in 
extreme  cases  porcelain  and  tooth  substance 
meet  one  another  as  mere  plane  surfaces  in 
apposition,  the  whole  stram  bemg  borne  by  the 
post  or  staple.  The  great  advantage  of  this 
form  of  retention  is  that  it  gives  a  good  holdfast 
with  the  minimum  of  tooth  cutting.  While  the 
post  is  no  strength  to  the  porcelain  itself,  but 
rather  the  reverse,  its  strong  condemnation 
by  some  writers  is  scarcely  justified  either  by 


Fig.  473. — Porcelaui  resturatiuu  of  icpnu-r  uf  devitalized 
front  tooth  retained  by  platiniuu  post  in  root- 
canal. 

an  upper  front  tooth  the  pin  should  be  towards 
the  lingual  side  rather  than  the  reverse,  the  dis- 
lodging force  being  the  outward  thrust  of  the 
lower  teeth,  which  tends  to  tilt  the  inlay  out- 
wards round  its  labial  edge  as  a  sort  of  pivot. 

As  an  illustration  of  the  application  of  the 
principles  here  set  forth,  the  preparation  of  an 
approximal  cavity  in  a  front  tooth  iuvohTiig 
the  cutting  edge  may  be  taken.  This  is  a  fairly 
common  cavity,  and  one  that  it  is  very  desirable 
to  fill  with  porcelain ;  at  the  same  time  there 
is  some  difficulty  in  getting  sufficient  strength 
and  anchorage  for  the  inlay. 

The  labial,  lingual,  and  cervical  walls  are 
trimmed  so  that  their  enamel  margins  are  strong 
and  of  even  contour.  These  three  walls,  or  sides, 
meet  the  floor,  or  pulp  wall,  at  a  definite  angle, 
which,  in  the  cervical  part  of  the  cavity,  may  be 
less  than  a  right  angle.  A  definite  step  is  made 
at  the  cuttmg  edge  by  extending  the  lower  third 
of  the  cavity  to  about  the  middle  of  the  tooth. 
This  is  most  easUy  done  by  grinding  enamel  and 


408 


dentine  a\\ay  together  with  a  tiat-tdged  stone, 
the  lingual  side  being  cut  slightly  deeper  than 
the  labial.  The  dentine  of  the  horizontal  part 
is  slightly  hollowed  out  so  as  to  give  a  definite 
seating,  and  also  some  resistance  to  lateral  stress, 
but  the  chief  part  of  the  anchorage  is  from  two 
platinum  pins,  one  near  the  end  of  the  horizontal 
part  of  the  cavity,  and  the  other  towards  the 
Imgual  end  of  the  cer\ical  wall.  These  pins 
are  parallel  to  one  another  and  to  the  long  axis 


A  P.  (•  I) 

Fig.  Hi. — Kestoration  of  corner  of  living  front  tooth. 

(A)  Labial  view  of  prepared  cavity. 

(B)  Side  view  of  prepared  cavity. 

(C)  Labial  view  of  finished  inlay  showing  anchorage  posts, 

(D)  Side  view  of  finished  inlay  showing  anchorage  posts. 


of  the  tooth ;  the  one  in  the  horizontal  part  of 
the  inlay  must  of  necessity  be  short,  about 
one  millimetre,  for  instance,  or  it  will  endanger 
the  pulp,  but  the  other  may  be  double  tliis 
length.  In  preparing  tlie  cavity  the  holes  must 
be  made  for  these  pins  in  the  approjiriate  filaces, 
and  of  a  size  to  take  them  easily. 

It  will  be  seen  that  this  mode  of  preparation 
provides  the  strongest  possible  shape  to  both 
tooth  and  porcelain  at  the  vulner- 
able cutting  edge,  and  the  exten- 
sion with  its  small  pin,  together 
with  the  pin  at  the  cervical  part 
of  the  cavity,  gives  excellent  re- 
tention; in  fact,  the  inlay  can 
hardly  come  out  without  break- 
ing, and  experience  of  inlays  made 
in  this  way  shows  that  breakage 
is    a    very    unlikely    accident    to  ^ 

happen.      The  "lighting  "  is  also 
very  good,  as  they  take  in  and 
reflect    what    light     there    is    in 
much  the  same  way  as  does  the  • 
rest  of  the  tooth. 

THE    MAKING    OF    INLAYS 

There  are  two  methods  of  fitting  the  inlay  to 
the  cavity  :  one  is  to  take  a  piece  of  ready-made 
porcelain,  such  as  an  artificial  tooth,  and  grind 
it  to  shape ;  the  other  is  to  pack  the  plastic 
porcelain  body  into  a  suitably  shaped  mould 
and  harden  it  by  heating  to  a  high  temperature. 

Methods  of  Grinding  to  Shape. — (1)  A  simple 
and  obvious  way  is  to  prepare  the  cavity  in  the 


ordinary  ntanner,  select  an  artificial  tooth  of  the 
proper  colour,  and  cut  a  piece  out  of  it  to  fit 
the  cavity.  The  process  resembles  the  fitting 
of  jjorcelain  teeth  on  iJrosthetic  work,  and  no 
special  directions  need  be  given  for  it.  Although 
this  method  is  a  tedious  one,  perfectly  satisfac- 
tory results  can  be  attained  with  it,  such  as  the 
case  shown  by  A.  S.  Underwood,  in  which  the 
inlays  were  still  in  place  after  twelve  years' 
service  (22). 

(2)  Many  years  ago  it  was  seen  that 
the  fitting  could  be  greatly  simplified  if 
the  cavity  were  of  such  a  kind  that  it 
could  be  made  exactly  circular  on  cross- 
section.  The  advantages  of  circular  shape 
are  twofold  :  first,  both  cavity  and  inlay 
can  be  shaped  with  mathematical  accuracy, 
and  secondly,  there  is  no  trouble  about 
the  orientation  of  the  inlay  in  placing  it 
in  the  cavity,  as  is  the  case  with  other 
shapes.  Even  this  method  took  a  great 
deal  of  time  \^hen  the  dentist  had  to  make 
his  own  inlay,  and  it  was  only  when  the 
Ball's  inlays  were  introduced  that  it  came 
into  general  use.  The  principle  of  the  Dall 
method  is  that  the  inlays  are  supplied 
ready  made  in  definite  numbered  sizes,  each  of 
which  fits  the  hole  made  by  the  similarly 
numbered  burr. 

The  fitting  of  a  Ball's  inlay  is  a  very  simple 
matter.  The  cavity  being  considered  a  suitable 
one,  it  is  cleared  of  carious  debris  and  reduced 
to  an  approximately  circular  form  with  ordinary 
burrs.  The  final  shaijing  is  accomplished  with 
the  special  burr  ;  this  should  be  of  a  size  just  too 


B  (J 

Fig.  475. 

(A)  Large  and  small  Dall's  inlays. 

(B)  The  corresponding  special  burrs. 

(C)  Cavities  prepared  for  Dall's  inlays. 

{All  natural  size.) 

large  to  enter  the  cavity ;  while  cuttmg,  its 
shaft  must  be  held  perfectly  steady  and  alter- 
nately advanced  and  -wdthdrawn  so  that  the 
burr  "  finds  its  way  "  without  the  exercise  of 
any  great  force.  The  burrs  are  so  gauged  that 
if  the  one  chosen  does  not  complete  the  shape, 
the  grinding  can,  without  difficulty,  be  con- 
tinued with  the  next  size  larger.  As  soon  as 
the  cavity  becomes  truly  circular,  the  grinding 
nuist   be  stopped  and  the  inlay  tried  in,  the 


409 


number  of  the  burr  last  used  indicating  which 
one  to  take ;  it  should  fit  the  cavitj^  tightly  : 
if  this  is  not  the  case,  the  cavity  must  be  ground 
further  until  it  takes  the  next  larger  size  of  inlay. 
The  sides  of  the  inlay  should  now  be  grooved 
and  the  cavity  undercut  to  correspond  ;  a  little 
thin  cement  is  now  smeared  over  both,  and  the 
inlay  carefully  and  firmly  pressed  into  place 
with  a  screwing  motion.  After  the  cement  has 
thorougUy  set  the  excess  may  be  removed,  and 
the  projecting  mass  of  porcelain  ground  level 
vwth  the  surface  of  the  tooth  and  polished. 

(3)  The  Howard  method  mvolves  the  fitting  of 
the  cavity  to  a  ready-made  porcelain  rod,  wliicli 
is  of  dovetail  shape  in  cross-section  and  tapers 
regularly  from  the  large  end  to  the  smaller  one, 
so  that  an  inlay  of  any  size  can  be  got  by  cut- 
ting out  the  appropriate  section. 

In  order  to  adapt  the  ca\-ity,  it  is  first  extended 
so  as  to  open  out  on  both  labial  and  lingual 
aspects ;  it  is  then  brought  to  the  proper  shape 
with  fine  flat  files,  the  rod  being  frequently 
tried  in  as  the  fitting  proceeds.  Wien  the 
Jomt  is  perfect,  the  parts  of  the  rod  that  project 
on  the  labial  and  lingual  sides  are  cut  off.  The 
section  that  is  to  form  the  inlay  is  then  slightly 
grooved  and  cemented  in  place  ;  on  account  of 
its  shape  it  can  only  be  introduced,  or  fall  out, 
from  the  labial  side.  \Vlien  the  cement  has 
become  hard  the  excess  of  porcelain  is  ground 
off  and  the  inlay  finally  polished. 

(4)  The  Jeffery  (12)  method  resembles  the 
Howard  in  that  a  ready-made  tapering  rod  of 
porcelain  is  used.  The  Jeffery  I'od  is,  however, 
of  conical  shape,  being  circular  in  cross-section, 
and  is  designed  for  the  filling  of  two  approximal 
cavities  in  one  operation ;  for  this  reason  it  is 
divided  down  the  middle,  the  t^^•o  halves  being 
joined  together  with  shellac,  each  half  bemg,  of 
course,   semi-circular  in  cross-section. 

To  fill  two  approximal  cavities  by  this  method. 


two  inlays  fixed  with  one  mix  of  cement,  care 
being  taken  that  the  shellac  joint  corresponds 
exactly  with  the  space  between  the  teetli. 
The  cement  is  now  allowed  to  set  thoroughly 
and,  preferably  at  a  subsequent  visit,  the  inlays 
are    separated    by    running    a    hot    instrument 


Fig.  476. 

(A)  Howard  inlay  rod  seen  from  side. 

(B)  Howard  inlay  rod  seen  from  one  end. 

(C)  ."Approximal  front  tooth  cavity  prepared  for  Howard  inlay. 


they  are  both  opened  out  to  the  labial  and 
lingual  aspects  of  the  teeth.  The  two  cavities 
are  then  brought  to  shape  by  means  of  the  large 
special  burr,  which  has  the  same  diameter  and 
taper  as  the  inlay  rod.  When  the  fitting  is 
complete,  the  section  that  is  to  make  the  inlays 
is  cut  out  of  the  rod,  and  each  half  well  grooved 
for  retention  ;  the  cavities  are  undercut,  and  the 


B 

Fig.   477. 

(A)  Jeffery  "  duplex  "  inlay  rod. 

(B)  Special    burr    for    simultaneous   preparation   of  two 

approximal  ca\'ities. 

(C)  Medial  cavities  in  the  two  central  incisors  prepared  for 

Jeffery  inlays. 

between  them,  and  are  then  dressed  down  and 
polished. 

There  are  several  other  methods  involving  the 
use  of  ready  prepared  rods,  such  as  Robin's  (20), 
and  Guttmann's  (7),  but  as  they  are  similar  in 
principle  to  those  already  described  they  need 
not  be  referred  to  further. 

(5)  Cornelius  Robbins  (19) 

Dhas  devised  a  convenient 
method  of  restoring  the 
broken  tip  of  a  front  tootli. 
A  fiat  English  porcelain 
tooth  is  selected.  Its  colour 
must  be  that  of  the  missing 
tip,  and  its  pins  far  enough 
apart  to  allow  holes  to  be 
drilled  for  them  into  the 
C  dentine,   parallel    with    the 

long  axis  of  the  pul]),  and 
far  enough  away  from  it  to  avoid  subsequent 
irritation  ;  the  thickness  at  the  pins  nuist  not  be 
less  than  the  length  of  the  proposed  restoration. 
The  broken  edge  of  the  tooth  is  then  made  flat, 
so  as  to  fit  against  the  flat  back  of  the  porcelain  ; 
the  holes  are  drilled  in  the  correct  position, 
which  is  indicated  by  pressing  the  pins  against 
a  piece  of  articulating  paper  held  against  the 


410 


end  of  the  tooth.  Any  fittmg  necessary  to 
perfect  the  joint  is  now  done,  and  the  excess 
of  porcelain  that  projects  over  the  margin  of 
the  natural  tooth  ground  off,  so  as  to  produce 
the  desired  contour ;  the  inlay  is  now  polished 
and  cemented  in  place. 

(6)  McCullough  of  Philadelpliia  has  described 
methods  of  making  inlays  that  somewhat  re- 
semble the  Steele's  detachable  facings,  as  the 
inlay  is  grooved  and  slides  over  a  metal  rod  fixed 
in  the  tooth.  For  a  detailed  description  the 
reader  is  referred  to  the  original  article  (16). 

Methods  of  Making  Inlays  by  Baking  in  a 
Mould. — All  the  methods  of  grinding  the  uilay 
to  shajie  have  the  great  advantage  that  the 
substance  of  the  porcelain  is  of  good  quality. 
A  high  grade  artificial  tooth  made  by  the  expert 
manufacturer  may  be  taken  as  a  specimen 
of  the  best  porcelain  that  can  be  obtained, 
and  in  baking  porcelam  in  the  laboratory  the 
aim  should  be  to  attain  the  same  degree  of 
excellence,  not  only  in  colour  but  also  in  strength 
and  density  of  structure.  In  order  to  get  the 
best  results  a  good  grade  of  porcelain  body 
must  be  used,  it  must  be  properly  packed,  and 
last,  but  by  no  means  least,  it  must  be  correctly 
.fired. 

The  Porcelain  Body. — This  is  not  a  definite 
chemical  compound,  nor  even  a  homogeneous 
mixture,  it  has  been  defined  by  Fickes  (5)  as  "a 
solidified  mass  composed  of  one  or  more  silicious 
substances,  suspended  in  a  fused  silicate  ".  Each 
manufacturer  keeps  the  composition  of  his  por- 
celain a  secret,  but  it  may  be  stated  generally 
that  the  "  silicious  substances  "  of  the  defuiition 
are  quartz  and  kaolm,  and  the  "  fused  sUicate  " 
Ls  in  the  main  felsf)ar,  which  owes  its  fusibility 
to  the  alkali  in  it ;  addition  of  more  alkali  causes 
the  fusing  point  to  be  lowered  still  further. 

There  is  a  class  of  porcelain  bodies  variously 
called  Plastic  Porcelain,  Mouldable  Porcelam, 
and  Fusible  Filling,  which,  like  ordinary  cements, 
are  supplied  in  packets  containmg  a  powder  and 
a  liquid.  BrUl's  Plastic  Porcelain  may  be  taken 
as  an  example  of  bodies  of  this  class.  This 
particular  substance  can  be  used  in  three  differ- 
ent ways  :  the  powder  can  be  mixed  mth  water 
or  alcohol  and  fired  like  any  other  ordinary 
porcelain ;  or  the  powder  and  liquid  can  be 
mixed  like  a  cement,  and  the  resulting  mass 
either  used  as  a  plastic  filling  (resembling  the 
rest  of  the  translucent  cements),  or  fired  and 
made  into  a  substance  like  porcelain,  fusing  at 
a  higher  temperature  than  the  powder  alone 
and  producing  a  body  somewhat  less  dense. 

In  deciding  on  a  porcelain  body  for  use,  the 
chief  qualities  to  be  noted  are :  colour,  trans- 
lucency,  fineness  of  the  powder,  strength,  and 
fusibility. 

The  two  first  can  readUy  be  judged  from  a 
test  piece.     The  fineness  of  the   powder  is  a 


matter  of  some  importance.  For  small  work 
like  uilays,  it  should  be  so  fine  that  it  gives  no 
"  sandy  "  feel  when  rubbed  between  the  fingers. 
If  too  coarse,  it  will  not  pack  hard,  nor  can  it 
be  carved  satisfactorily ;  it  can,  however,  be 
quickly  reduced  to  the  proper  fineness  by  gruid- 
ing  in  an  agate  mortar.  Some  idea  of  the 
strength  can  be  obtamed  by  breaking  a  test 
piece  with  the  fuigers,  but  an  accurate  estimation 
can  only  be  made  by  using  special  apparatus. 
The  results  of  a  number  of  such  estimations  are 
indicated  in  the  foUowmg  table.  In  explanation 
it  may  be  said  that  Le  Ci-on's  (14)  figures 
represent  crushing  strength  in  thousands  of 
pounds  to  the  square  inch ;  Jenkins  (13)  gives 
crushing  strength  in  pounds  per  square  centi- 
metre. Head  (9)  tested  the  shearing  strength, 
his  first  column  indicating  the  steady  pressure 
in  jjounds  requu'ed  to  shear  a  piece  of  porcelain 
of  given  size  and  shape,  the  second  the  tension 
of  a  rubber  band,  in  ounces,  required  to  produce 
the  same  effect  by  causing  a  weight  to  be  im- 
pacted against  the  test  piece.  Wlieeler  (23) 
gives  the  tensile  force,  in  pounds,  required  to 
pull  platinum  pins  from  the  porcelain  in  which 
they  were  baked,  the  machine  used  being  that 
employed  to  test  the  strength  of  ordinary 
artificial  teeth.     The   very   variable   nature   of 


Comparative  Strengths  of 

Porcelain 

C^„:  Jenkins 

Head 

Wheeler 

Allen 

27 

— 

'^  -2 

— 

Ash's  High 

23 

— 

— 

— 

45 

Ash's  Low 

— 

— 

— 

— 

30-5 

Brewster  Foundation 

20 

— 

— 

— 

— 

Brewster  Enamel     . 

23 

— 

21 

8 

19 

Close 

40 

782-5 

— 

— 

— 

Close-Whiteley 

— 

225 

— 

— 

— 

Consolidated    Con- 

tinuous Gmn 

30 

520 

— 

— 

— 

Consolidated  Inlay  . 

15 

460 

— 

— 

— 

Jenkins 

28 

924 

26 

6 

32-5 

Jenkins  Improved   . 

— 

— 

15 

8 

. — 

Parker       .        .         [ 

— 

— 

— 

— 

unbroken 

in  test 

Wliite 

32 

— 

26 

6 

33-5 

Whiteley  Inlay 

16 

430 



41 

Whiteley  Special 

— 

787-5 

— 

— 

the  material  experimented  on  would  make  dis- 
crepancies in  these  results  likely,  but  they  give 
valuable  information  as  to  the  comparative 
strengths  of  various  bodies.  As  a  matter  of 
fact  most  if  not  all  of  them  are  strong  enough  for 
the  purpose  ij  they  are  manipulaied  properly ; 
careless  use  will  ruin  the  best  body  ever  made. 
The  porcelain  bodies  are  of  various  degrees 
of  fusibility,  but  can  be  divided  into  two  classes, 
the  high  and  the  low ;  and  a  very  convenient, 
although  of  course  perfectly  arbitrary,  dividing 
point  between  them  is  the  melting-point  of  pure 
gold.     In  a  general  way  it  is  easy  to  make  a 


411 


comparison  between  the  properties  of  the  t\\o 
classes,  but  any  accurate  treatment  of  the 
question  in  a  scientific  sense  is  liardly  possible, 
partly  because  the  compositions  of  tlie  porcelain 
bodies  are  trade  secrets,  and  partly  because,  as 
with  all  other  proprietary  articles,  there  is  no 
guarantee  that  their  coinjjosition  is  constant ; 
for  all  that  can  be  told,  the  body  used  to-day 
may  differ  in  some  important  particular  from 
that  of  the  same  name  used  a  year  ago. 

In  the  matter  of  colour  and  general  apj)earance 
there  is  little  to  choose  between  high-  and  low- 
fusing  bodies ;  complahit  has,  however,  been 
made  that  some  of  the  latter  lose  their  glaze 
in  a  few  months,  with  the  result  that  a  dark 
stam  settles  on  the  surface  ;  the  jn'obable  reason 
for  this  is  excess  of  soluble  alkali  in  their 
composition. 

Low-fusing  bodies  are  more  easy  to  manipu- 
late ;  their  fusing  takes  less  time  and  its  tempera- 
ture can  be  gauged  with  sufficient  accuracy  by 
inspection.  They  cause  less  wear  and  tear  to 
the  furnace,  and  can  be  baked  m  a  gold  matrix. 
The  high-fusing  bodies  require  practically  a 
white  heat,  which  is  very  trying  to  the  eyes,  and 
very  difficult  to  gauge  at  all  accurately ;  and  as 
30°  C.  may  make  a  good  deal  of  difference  to  the 
quality  of  the  porcelaui,  it  is  almost  necessary 
to  use  some  sort  of  pyrometric  device. 

High -fusing  bodies  possess  the  great  ad- 
vantage that,  like  true  porcelain,  they  develop 


their  high  strength,  density,  and  glaze  without 
loss  of  shaj)e ;  on  the  other  hand  some  of  the 
workers  who  use  Jenkins'  body  advise  heating 
it  until  it  "flows",  so  that  contourmg  with  it 
would  hardly  l>e  possible.  In  the  matter  of 
strength,  the  high-fusing  porcelains  on  the 
whole  take  the  lead,  although  it  must  not  be 
forgotten  that  some  of  them  are  actually  inferior 
to  the  Jenkins  body  in  both  strength  and 
density. 

In  spite  of  individual  preferences,  it  would 
not  be  far  wTong  to  say  that  while  low-fusing 
bodies  have  the  advantage  of  convenience,  the 
high  make  better  porcelain ;  and  this  is  appar- 
ently the  opinion  of  the  manufacturers,  who 
invariably  use  high-fusing  materials  in  the 
making  of  thek  artificial  teeth. 

The  follo^vulg  table  will  give  some  idea  of  the 
fusing  points  of  several  of  the  porcelain  bodies 
in  common  use  :  the  figures  may  be  regarded 
as  approximate  and  are  collected  from  various 
authorities,  who  do  not  always  agree  ^^■ith  one 
another. 

Packing  the  Porcelain. — The  aim  is  to  get  the 
maximum  density,  or  in  other  words  the  greatest 
amount  of  body  in  a  given  space.  The  difficulty 
to  contend  with  is  that  the  grains  are  of  irregular 
shapes,  so  that  air  spaces  are  inevitably  left 
lietween  them.  If  the  body  is  merely  placed 
in  the  mould  with  brush  or  s^satula,  the  grains 
will  lie  in  a  perfectly  haphazard  fashion,  like 


Fusibility   Table 


F. 

Dazzling  White  Heat      2600° 


C. 


Wliite  Heat 


2500°- 
.    2400°- 


2300°- 
Orange  Yellow  Heat     .    2200°- 

2100°- 


Orange  Heat 

2000°— 
1900°— 

1800°— 

Bright  Red  Hrat  . 

.    1700°— 

1600°— i 

Red  Heat 

.    I. 500°— 

-1400° 


-1300° 


-1200° 


-1100° 


-1000° 


-900° 


-800° 


-Parker's  Body  (1420° 


-Allen  (1280°). 

-Dental  Manufacturing  Co.  Foundation  (1260°). 

Close  (1260°). 
-Brewster  Foundation  (1215°). 

-Dental  Manufacturing  Co.  High  Fusing  (1170°). 
^Consolidated  Inlay  (1170°). 
-S.S.W.  High  Fusing  (1150°  1) 
-Brewster  Enamel  (1140°). 
Fellowship  Fusible  Filling. 

-Dental  Manufacturing  Co.'s  Mediiun  (1093°). 
-Gold  melts,  S.S.W.  Medium  (1065°). 
-Ash  High  Fusing  (1035°). 
Brill's  Plastic  Porcelain. 


-Brewster  Gold  Matrix  (960" 


-Ash  Low  Fusing,  Jenkins  (850°  to  900° 


412 


bricks  tipped  out  of  a  cart.  The  best  way  to 
get  the  grains  packed  as  closely  as  they  can  go 
is  to  have  the  body  damp  and  the  mould  kept 
ui  constant  vibration ;  under  these  conditions 
the  grains  settle  themselves  together,  and  the 
moisture  that  occupied  their  inter-spaces  appears 
on  the  surface.     A  simple  way  of  vibrating  the 


Fig.   478. — Settling    porcelain    solidly    in    matrix    by 
vibration. 


mould  is  to  hold  it,  or  the  tray  in  which  it  is 
invested,  in  a  pair  of  spring  tweezers,  and  gently 
draw  a  .serrated  rod,  or  coarse  file,  across  their 
handles.  As  the  moisture  appears  it  can  be 
soaked  up  «'ith  blotting  paper. 

Even  when  the  grains  are  packed  as  closely 
as  they  can  go,  the  mass  is  still  far  from  solid, 
and  if  heated  to  its  fusmg  pohit  will  show  a 
considerable  contraction,  corresponding  in 
amount  to  that  of  the  air  spaces  obliterated. 
If  baked  free  from  a  mould,  as  artificial  teeth 
are  baked,  the  mass  contracts  uniformly  to- 
wards its  centre  and  attains  its  maximum 
den.sity.  If  baked  wt  a  mould,  the  contraction 
still  takes  place,  and  causes  fissures  or  spaces  to 
appear  in  the  substance  of  the  porcelain,  or 
between  it  and  the  mould ;  or  else  the  mould 
itself  is  drawn  out  of  shape.  The  latter  result 
would  be  disa.strous  to  an  inlay,  so  that  the  best 
way  to  counteract  the  effect  of  shrinkage  is  to 
cut  the  mass  into  two  or  more  sections,  by  a 
fine  division  running  right  down  to  the  floor 
of  the  mould.  Each  section  is  then  free  to 
contract  towards  its  own  centre,  and  the  result- 
ing chinks  can  be  filled  up  at  a  subsequent 
bakmg. 

The  Firing  of  the  Porcelain. — In  the  process 
of  firing,  the  "fused  silicate  ",  of  Fickes'  defini- 
tion, must  be  properly  melted  so  as  to  get  the 
necessary  cohesion,  but  the  particles  of  "  sili- 
cious  substances  "  must  retain  their  identity 
so  that  the  essential  structure  of  the  porcelain 
is  not  lost,  as  it  would  be  if  the  whole  mass  were 
melted  into  a  homogeneous  glassy  mixture. 
The  correct  point  to  stop  the  firing  is  when  all 
the  contraction  has  taken  place,  and  the  surface 
become  properly  glazed,  but  before  any  change 
of  shape,  or  loss  of  sharpness  of  outline,  has 


occurred.  Both  over-  and  under-fusmg  produce 
a  material  deficient  in  strength ;  for  instance, 
Weston  Price  (18)  found  that  both  Brewster 
and  Jenkin  bodies  were  nearly  twice  as  strong 
if  properly  fused  than  if  over-  or  under-baked  to 
the  extent  of  85°  C. ;  Bluell  (1)  gives  similar 
results. 

Time  has  an  importance  only  second  to  that 
of  temperature  in  the  fusing  of  porcelain ;  some 
experiments  of  J.  Byram  (2)  show  that  bodies 
that  normally  fuse  at  or  above  1200°  C,  can  be 
satisfactorily  fired  by  keeping  them  at  the 
melting-point  of  gold  for  a  long  time.  Close 
body  and  Bre%\.ster  foundation  requiring  about 
an  hour.  White  and  Whiteley  about  three 
hours,  and  Consolidated  six  hours  or  more. 

There  are  many  kinds  of  furnace  for  the  firmg 
of  porcelain.  The  heating  is  effected  either  by 
electrical  means,  or  by  the  burning  of  gas,  oil, 
or  (in  the  older  furnaces)  coke. 

Excellent  electric  furnaces  are  on  the  market ; 
among  many  may  be  mentioned  the  Pelton, 
the  Price,  and  the  Hammond.  The  principle 
of  all  of  them  is  the  same,  the  heating  being 
effected  by  the  passage  of  an  electric  current 
through  a  platinum  wire  embedded  in  the 
furnace  walls.  In  the  best  furnaces  the  heating 
of  the  interior  is  made  uniform  by  a  closer 
winding  of  the  wire  towards  the  entrance.  Loss 
of  heat  is  guarded  against  by  having  a  thick 


A  BCD 

Fig.   479. — Stages  of  firing  of  porcelain. 

(A)  Plaster  cast  of  mould  showing  original  size  of 

pellets  B,  C,  D. 

(B)  Pellet  of    S.S.   white  medium-fusing  porcelain 

fired  to  1050°  C.  ("  biscuited  "). 

(C)  Similar  pellet  fired  to  the  proper  fusing  point, 

1070°  C. ;  note  the  glaze  without  loss  of  shape. 

(D)  Over-fired  pellet,  heated  to  1130°  C. ;  note  loss 

of  sharp  outline. 

non-conducting  jacket  and  a  close-fitting  door; 
the  less  loss  of  heat  there  is,  the  greater  is  the 
temperature  that  can  be  obtained  without  undue 
heatmg  of  the  platinum  wire.  The  amount  of 
power  required  to  run  a  furnace  will,  of  course, 
vary  with  its  size ;  a  moderate-sized  one  might 
take  anything  up  to  half  a  kilowatt.  Custer  (4) 
and  others  (6  and  8)  give  directions  for  making 
a  furnace ;    the  writer  has  known  a  home-made 


413 


furnace  last  several  years,  in  spite  of  heating 
many  dozens  of  times  to  1100°  C.  and  over. 

While  the  electric  furnace  is  far  the  most 
convenient,  results  just  as  good  can  be  obtained 
by  heating  with  gas  or  oU,  provided  the  burnt 
or  partly  burnt  gases  are  excluded  from  the  interior 
of  the  muffle.  Various  kinds  of  gas  and  oil 
furnaces  are  to  be  obtained,  some  of  them 
caj)able  of  firing  the  most  refractory  bodies  on 
the  market. 

The  methods  used  for  gaugmg  the  temperature 
are — 

(1)  Inspection. — This  is  satisfactory  only  if 
the  porcelain  fuses  at  a  red  heat.  It  is  practi- 
cally impossible  to  see  details  with  sufficient 
accuracy  in  a  white-hot  furnace,  even  if  a  strong 
beam  of  light  is  thrown  on  the  work  from  an 
external  source,  as  has  been  recommended. 

(2)  Test  Pieces. — These  consist  of  small  pieces 
of  the  same  body  placed  on  a  tray  or  in  a  loop 
of  platinum  wire  and  fired  side  by  side  with  the 
work.  The  test  piece  is  taken  out  from  time  to 
time  and  the  progress  of  the  baking  judged 
thereby.  This  is  a  fairly  satisfactory  method, 
although  the  small  piece  fires  more  quickly 
than  the  work  itself ;  it  is  much  better  than 
the  plan  of  taking  the  work  itself  out  for  in- 
spection, which  cools  it  down  to  quite  an  un- 
known degree,  so  that  it  is  most  difficult  to 
judge  just  how  long  it  must  be  baked  again  to 
raise  it,  first  to  its  former  temperature,  and  then 
as  nuich  more  as  may  be  necessary,  especially 
as  the  furnace  has  been  getting  hotter  all  the 
time. 

(3)  Melting  of  Substances  of  Known  Fusing 
Point. — (a)  Tlie  simplest  of  these  methods  is  to 
use  a  pellet  of  pure  gold  as  the  test,  and  if  the 
body  fuses  at  a  higher  temperature  than  1065°  C, 
to  leave  it  in  the  steadUy  heatmg  furnace  for  a 
certain  definite  time  after  the  meltmg  of  the 
gold,  which  must  be  determined  by  trial  for  the 
particular  furnace,  body,  and  current  voltage. 

(b)  Seger's  cones  of  the  proper  fusing  pomt 
for  the  particular  body  may  be  obtained. 

(c)  Le  Cron's  pellets  of  gold  and  platinum 
alloy  afford  a  very  simple  and  reliable  means  of 
gauging  the  temperature.  The  proportions 
given  by  Le  Cron  are  as  follows — 


Percentage 

Body. 

Composition  of  Pellet 

Gold 

Platinum 

Allen      . 

89 

11 

Close      . 

90i 

9.^ 

Wliite  Inlay 

91 

9 

Brewster  Foundation 

OU 

8i 

Brewster  Enamel 

98 

o 

^Vhiteley  Inlay     . 

921 

n 

Consolidated  Inlay 

92i 

7i 

White  Medium      . 

mo 

0 

The  pellets  are  used  in  connection  with  an 
ingeniously  shaped  crucible,  which  is  placed  on 
the  furnace  floor  next  to  the  work  that  is  being 
fired.  The  crucible  has  two  oj)enings,  one  in 
the  roof,  which  is  just  too  small  to  allow  the 
pellet  to  pass,  and  the  other  larger  one  in 
the  side.  At  the  commencement  of  a  bakmg  the 
pellet  is  placed  on  the  top  of  the  crucible,  resting 
in  the  smaller  hole ;  when  its  fusing  point  is 
reached  it  falls  into  the  well  ui  the  crucible  floor, 
from  which  it  can  be  recovered,  when  cold, 
for  use  m  the  next  baking.  As  the  pellets 
do  not  tarnish,  they  can  be  used  over  and  over 
agam. 

[d)  If  the  furnace  always  heats  up  in  a 
perfectly  regular  mamier,  its  temperature  can 
be  gauged  by  the  melting  of  a  piece  of  metal 
of  low  fusing-point  such  as  lead,  placed  in  some 
position  where  the  temperature  bears  some 
definite  relation  to  that  of  the  interior  of  the 
furnace.  Such  an  arrangement  can  be  made 
to  actuate  an  alarm  or  an  automatic  cut-out. 

(4)  Thermo-electric  Pyrometer. — This  consists 
of  a  platinum-rhodium  couple,  the  junction 
of  which  is  placed  in  tlie  furnace  at  the  point 


Fio.   480. — Le    Cron's    Pyrometer   PeUet    in    crucible, 
ready   for   use.     Nat^u'al   size. 

whose  temperature  is  required  to  be  known. 
The  free  ends  of  the  couple  are  connected  with 
a  very  delicate  galvanometer,  and  as  the  current 
is  proportional  to  the  difference  between  the 
temperatures  of  the  hot  and  cold  junctions,  the 
excursion  of  the  needle  of  the  galvanometer  can 
be  made  to  indicate  degrees  of  temperature. 
As  the  electro-motive  force  of  the  couple  may 
be  only  about  '02  volt,  it  will  be  understood 
that  the  pyrometer  is  a  somewhat  delicate 
instrument ;  nevertheless,  if  well  made,  it  wiU 
last  a  very  long  time.  This  is  one  of  the  most 
satisfactory  and  easy  ways  of  gauging  the 
temperature,  and  if  used  with  reasonable  care 
and  intelligence  w  ill  enable  the  operator  to  get 
a  properly  fused  piece  every  time. 

Effects  of  Over-firing. — These  are  loss  of  shape, 
loss  of  colour,  loss  of  strength,  and  porosity. 

Loss  of  strength  and  shape  have  already 
been  mentioned,  loss  of  colour  can  to  some 
extent  be  remedied  by  painting  with  coloured 
enamel  and  refiring. 

The  most  mischievous  defect  of  all  is  porosity, 
although  this  may  be  due  to  other  causes  besides 
over-firing.     The    bubbles   may   have   been   in 


414 


the  mass  from  the  first,  owing  to  bad  packing, 
and  this  is  a  much  more  frequent  cause  than 
most  workers  might  imagine.  They  may  be 
due  to  steam  generated  by  putting  a  moist  mass 
into  the  hot  furnace.  Porosity  may  also  be 
caused  by  insufficient  allowance  for  contraction  ; 
m  this  case  it  ^^■ould  take  the  form  of  fissures 
rather  than  a  diffuse  sponginess.  If  not  due  to 
either  of  these  causes  the  bubbles  must  result 
from  the  evolution  of  gases,  owing  to  the  de- 
composition of  some  constituent  of  the  porcelain, 
or  of  some  foreign  substance  mixed  with  it. 
Most  ordinary  volatile  substances  would  dis- 
appear before  the  body  had  become  viscous 
enough  to  imprison  the  bubbles,  but  possible 
gases  that  might  be  given  off  at  a  high  tempera- 
ture are  water  and  sulphur  dioxide,  the  latter 
being  readily  provided  by  the  accidental  in- 
clusion of  a  little  plaster  of  Paris. 

If  the  body  has  become  porous,  there  is 
nothing  to  do  but  dissolve  it  out  of  the  mould, 
wholly  or  in  part,  by  hydrofluoric  acid,  and 
replace  it  with  fresh  porcelain,  or  else  to  start  a 
new  inlay  altogether. 

THE   MAKING  OF  A   FUSED  INLAY 

The  mould  or  matrix  is  usually  made  of  gold  or 
platinum  foil,  and  there  are  two  ways  of  adapting 
it  to  the  proper  shape.  The  ordinary  one  is  to 
swage  it  into  the  cavity  or  some  reproduction 
of  it ;  in  this  case  the  inlay  is  necessarily  smaller 
than  the  cavity  by  the  thickness  of  the  foil 
lining.  The  other  way,  generally  associated 
with  the  name  of  Peck,  is  to  adapt  the  foil  to  a 
cement  impression,  which  might  be  called,  by 
a  photographic  analogy,  the  "negative"  of 
the  cavity,  as  opposed  to  the  "  positive  "  ob- 
tained by  first  taking  an  impression  and  then 
casting  a  model  from  it ;  if  the  matrix  is  made 
by  this  method,  its  inside  measurement  will 
exactly  equal  that  of  the  original  cavity,  no 
matter  what  the  thickness  of  the  foil  may  be. 

Ordinary  Method. — The  cavity  having  been 
prepared,  the  matrix  may  be  swaged  directly 
into  the  cavity  or  into  a  model  of  it. 

If  a  model  is  used,  an  imjiression  must  first 
be  taken  in  some  plastic  material,  the  ones  most 
used  being  ordinary  mcdellmg  composition,  den- 
tal lac,  gutta-perclia,  and  osteo-plastic  cement. 
To  prevent  undue  adhesion  the  cavity  must  be 
either  dusted  with  French  chalk,  wetted,  or,  if 
cement  is  to  be  used,  vaselined.  In  a  labial 
cavity,  an  impression  in  one  of  the  materials 
that  "soften  by  heat  can  be  obtained  by  the 
simple  process  of  warming  one  end  of  a  stick 
of  the  impression  material  and  using  the  other 
one  as  a  handle  to  press  it  into  the  cavity.  In 
approximal  cavities,  and  in  the  case  of  cement 
in  all  cavities,  a  metal  strip  or  tray  is  required, 
both  to  press  the  material  into  the  cavity  and 


to  prevent  undue  thickness  of  the  impression, 
which  might  hinder  its  \\ithdrawal  from  the 
cavity.  In  some  cases  Dowsett's  trays  aaIII  be 
found  useful.  In  others,  especially  approximal 
cavities  in  which  there  is  not  too  much  space, 
a  convenient  plan  is  to  press  the  material  in 
with  a  band  of  thin  steel  or  German  silver,  wide 
enough  to  reach  from  the  tip  of  the  tooth 
down  over  the  cervical  margin,  and  long  enough 
to  project  on  the  labial  and  lingual  sides,  so  that 
it  can  be  gripped  by  the  finger  and  tliumb  of 
each  hand  when  pressing  the  material  into  the 
cavity.  The  strip,  preferably  vaselined,  is  placed 
in  the  space  first,  and  then  the  small  j^ellet  of 
softened  modelling  material  is  quickly  packed 
into  the  cavity  and  pressed  well  home  with  the 
strip.  From  this  impression  the  model  is  made, 
cement,  Spence  metal,  or  amalgam  being  most 
commonly  used  for  the  purpose. 

Cement  is  a  very  satisfactory  substance  to 
make  a  model  of ;  it  is  easily  manipulated,  and 
is   quite   hard   enough   to   stand  the  necessary 


Fig.   481. — Taking  impression  of  cavity  with 
composition  or  lac,  and  metal  strip. 

piessure.  Care  must  be  taken  to  smear  it  well 
into  the  parts  of  the  impression  that  represent 
the  enamel  margins.  If  cement  is  cast  into 
cement,  the  impiression  must  be  well  vaselined, 
and  the  model  part  mixed  rather  thick,  rolled 
in  the  fingers  with  French  chalk,  and  packed 
with  considerable  pressure. 

Spence  metal,  or  sulphide  of  iron,  can  be 
poured  into  a  dental  lac  impression,  and  gives 
a  very  sharp  model.  A  little  practice  is  re- 
quired to  pour  it  satisfactorily.  If  heated  in 
a  spoon  it  will  be  observed  that  it  is  in  the  best 
condition  for  pouring  M'hen  just  above  its  melt- 
ing point,  a  higher  temperature  causing  it  to 
become  thick  and  full  of  bubbles;  M'hen  it  is 
melted  the  ladle  should  be  taken  oif  the  flame 
and  gently  tapped  on  the  bench  to  get  all  the 
bubbles  to  the  surface ;  when  these  have  all 
disappeared  and  while  the  material  is  still  quite 
fluid,  it  should  be  quicldy  poured  into  the 
impression,  care  being  taken  to  avoid  inclusion 
of  air  in  the  deeper  parts. 

Amalgam  requires  no  special  description; 
it  is  not  so  satisfactory  as  either  Spence  metal 
or  cement,  for  general  use. 

The    use    of    a    model    has    several    great 


415 


advantages.  It  is  far  more  easy  to  swage  the 
foil  to  a  model  than  to  the  cavity  itself,  partly 
because  there  are  no  adjoining  or  opposing 
teeth  to  get  in  the  ^vny,  and  no  patient  to 
consider,  and  partly  because  the  mechanical 
swaging  press  can  be  used  instead  of  the  much 
more  tedious  method  of  hand  instruments. 
Moreover,  the  work  can  be  done  at  leisure 
at  any  convenient  time,  or  better  still  the  den- 
tist can  get  some  one  else  to  do  it  for  him. 
On  the  other  hand,  no  method  of  swaging  on  a 
model  can,  as  a  rule,  give  as  good  a  fit  and  as 
sharp  a  margin  as  can  be  obtained  by  directly 
burnishing  the  foil  to  the  cavity  itself.  The 
method  about  to  be  described  combines  the 
advantages  of  the  use  of  a  model  with  those  of 
direct  swaging  into  the  tooth  ca\'ity. 

The  preliminary  fitting  is  done  to  a  model. 
The  matrix  may  be  made  from  gold,  platinum, 
or  some  combination  of  the  two.  Gold  is  easier 
to  swage,  but  its  very  pliability  makes  it  neces- 
sary to  use  a  thicker  sheet  than 
would  be  the  case  with  platinum ; 
it  can,  moreover,  only  be  used  Avith 
lo^\•-fusing  bodies.  Platinum  has  the 
great  advantage  that  it  allo^\■s  the 
use  of  porcelain  of  any  degree  of 
fusibility.  Strength  for  strength,  it 
is  thinner  than  gold,  and  although 
a  little  more  care  may  be  required,  it 
is  safe  to  say  that  any  matrix  that 
can  be  made  at  all  can  be  made  mth 
platinum;  the  difference  is  at  a 
minimum  in  the  beautifully  soft 
platinum  now  made  for  the  purpose  ; 
the  full  iiliability  is  brought  out  by 
careful  annealing,  preferably  in  the 
electric  furnace. 

The  thickness  is  a  matter  of  importance ;  a 
certain  thickness  is  necessary  to  give  the  mould 
strength  to  keep  its  shape  during  the  various 
manipulations ;  moreover,  it  is  of  no  use  at  all 
to  have  a  mould  thinner  than  the  average  size 
of  the  grains  of  the  cement  forming  the  lute. 
Head  (10)  and  Poundstone  (17)  have  made 
careful  measurements,  both  of  the  size  of  the 
grains  and  of  the  minimum  thickness  of  a 
cement  film  setting  between  two  plane  surfaces 
under  pressure.  From  their  estimations  it 
appears  that  foil  up  to  jy^gTy  inch  thick  may 
be  quite  safely  used.  It  so  happens  that  soft 
platinum  foil  of  this  thickiaess  is  pliable  enough 
for  all  cavities  of  ordinary  size,  and  stiff  enough 
to  keep  its  shape  if  used  ■\\dth  reasonable  care, 
and  this  is  the  foil  that  on  the  \\-liole  will  be 
found  most  suitable  for  general  work ;  in  making 
very  small  inlays,  foil  ^^jyjj  inch  thick  may 
be  used,  on  account  of  its  greater  pliability,  this 
quality  being  much  more  than  doubled  by 
halving  the  thickness.  WTien  freed  from  the 
matrix,  the  inlay  wiU  go  further  into  the  cavity 


by  an  amount  represented  by  the  foil  thickness, 
and  this  wiU  reduce  the  discrepancy  between  the 
sizes  of  the  inlay  and  cavity  in  all  except  those 
that  have  absolutely  parallel  walls. 

In  order  to  make  the  matrix,  the  model  of 
the  cavity  should  first  be  fixed  to  the  bed 
plate  of  the  swaging  press  ^v-ith  plaster  or 
composition. 

_  A  piece  of  the  foil  is  then  cut,  of  sufficient 
size  to  leave  a  margin  all  round  the  cavity. 
This  is  at  first  carefully  adapted  by  hand,  mth 
the  aid  of  ball-ended  tweezers,  and  pieces  of 
cotton- wool,  amadou,  or  chamois  leather.  The 
middle  parts  should  be  worked  down  first,  and 
advance  made  gradually  towards  the  margin. 
A  piece  of  the  thinnest  china  silk  jslaced  between 
the  foil  and  the  cavity  during  the  preliminary 
part  of  the  hand  fitting  will  greatly  help  in  the 
prevention  of  tears.  A  few  small  tears  are 
almost  inevitable,  and  unless  they  are  near  the 
margin  they  will  not  prejudice  the  fit  of  the 


Fig.  482. 

(A)  The  tooth  cavity. 

(B)  Impression  of  cavity  iia  composition. 

(C)  Cement  model  of  tlie  impression  moimted  on  bed-plate  of  swager. 

inlay ;  in  fact  it  may  be  said  that  the  relief  they 
afford  to  the  foil  prevents  the  necessity  of  having 
so  much  fullness  at  the  margin,  v^ith  consequent 
wrinkles  that  must  be  flattened  out.  The 
fitting  of  a  foil  matrix  is  not  quite  comparable 
to  the  swaging  of  a  metal  denture,  which  is 
entirely  a  matter  of  stretching  of  the  material. 
Of  course  some  amount  of  stretching  of  tlie 
foil  does  take  place,  but,  except  in  a  simple 
case,  there  is  almost  bound  to  be  some  \\Tinkling 
or  folding  at  the  edge  or  some  tear  in  the  floor ; 
the  best  plan  is  to  get  as  much  real  stretching 
as  possible,  and  for  the  rest  make  a  compromise 
between  too  much  wrinkling  on  the  one  hand 
and  too  much  tearing  on  the  other. 

\Vlien  the  fltting  is  complete,  any  ^Tinkles 
on  the  margin  must  be  carefully  burnished 
out,  so  that  the  outline  of  the  enamel  edge  is 
shaqaly  and  evenly  defined  the  whole  way 
round.  For  this  purpose,  as  also  for  the  greater 
part  of  the  fitting,  Booth  Pearsall's  rotary 
burnishers  are  very  useful ;  failing  these,  a 
perfectly  smooth  instrument  must  be  employed. 


416 


so  that  the  foil  may  not  be  cut  or  torn  at  the 
margin. 

The  metal  plate  carrying  the  model  and  foil 
matrix  is  now  transferred  to  the  swaging  press, 
and  any  warp  or  sjiringiness  removed  by  press- 
ing \\ell  \\ith  the  water-bag  plunger. 

The  matrix,  which  should  now  fit  perfectly, 
must  at  this  stage  be  removed  from  the  model. 
In  order  to  prevent  distortion,  it  should  first 
be  filled  with  some  substance  that  ^^'ill  sufficiently 
support  it,  and  that  can  be  easily  and  com- 
pletely removed  after  the  matrix  is  invested. 
Wax,  gutta-percha,  or  camphor  may  be  used 
for  this  jnirpose.  Of  the  various  kinds  of  gutta- 
percha the  most  suitable  is  the  pink  "  base- 
plate " ;  it  should  be  packed  into  the  matrix 
comparatively  cold,  so  that  it  will  not  adhere 
too  firmly  to  the  platinum.  After  the  invest- 
ment has  set  it  can  readily  be  removed  if  it  is 


(A)  Asli's  Inlay  Press. 

(B)  The   bed-plate,    to   which   is   fixed    the    cement 

model. 

(C)  The  water-bag  plimger  for  fitting  thin  foil. 

(D  and  E)  Iron  plunger  and  hard  rubber  block  for 
heavy  swaging. 

warmed  on  the  top  surface ;  if  the  mould  itself 
is  heated,  there  is  danger  of  the  gutta-percha 
sticking  to  the  platinum  foil  and  pulling  it 
away  from  the  investment.  If  wax  is  used 
it  should  be  that  supplied  for  casting  and 
guaranteed  to  leave  no  fixed  residue  on  ignition. 
The  most  convenient  substance  of  all  is  camphor. 
If  small  pieces  are  packed  into  the  mould,  they 
can  readily  be  made  to  cohere  into  a  solid  mass 
which  acts  as  a  very  satisfactory  support  to 
the  foil ;  after  investment  the  camphor  can 
easily  be  removed  with  a  blast  of  hot  air,  as  it 
volatilizes  at  a  low  temperature  without  melting 
to  a  liquid  and  so  rumiing  into  the  pores  of  the 
investment,  as  wax  does. 

Various  substances  are  used  for  investing  the 
matrix,  such  as  asbestos  powder,  alone  or  mixed 
with  plaster,  clay,  or  kaolin,  or  either  of  these 
two  latter  by  themselves.  As  useful  an  invest- 
ment as  any  is  a   mixture  of  three  parts  of 


powdered  silica  and  one  part  of  plaster.  The 
investment  should  be  mixed  with  water  to  make 
a  stiff  batter,  a  portion  placed  in  a  little  platinum 
tray,  and  the  matrix  with  its  contained  camphor 
gently  settled  into  place  by  vibration.  The 
camphor  may  be  removed  directly  the  invest- 
ment has  set.  It  may  be  observed  that  the  chief 
function  of  the  investment  is  to  give  a  ready 
means  of  handling  the  matrix  \\dthout  bending 
it ;  it  cannot  really  be  relied  upon  to  counteract 

A  B 

Fig.   48-i. 

(A)  The  foil  matrix. 

(B)  Matrix  invested  in  small  platinmn  tray. 

the  tendency  of  the  porcelain  to  warp  the 
foil. 

The  first  part  of  the  porcelain  should  have  a 
much  higher  fusing-point  than  that  used  for 
the  more  superficial  layer.  The  matrix  should 
be  wetted,  and  tlie  body  thoroughly  packed  by 
vibration  in  the  manner  already  described. 
Wlien  completely  solid  it  is  carved  to  shape  so 
as  roughly  to  represent  the  dentine  of  the 
ntissing  part  of  the  tooth,  a  margin  of  t;V  of 
an  inch  or  more  being  left  free  from  porcelain 
all  the  way  round  inside  the  actual  cavitj'  edge. 
The  object  of  this  is  to  allow  the  refitting  of 
the  foil  to  the  enamel  margin  of  the  tooth  cavity 
after  the  foundation  body  has  been  fired,  and 
consequently  after  all  possibility  of  ^^■arping 
has  passed,  as  the  foundation  body  is  never 
heated  to  its  fusing  point  in  the  firing  of  the 
subsequent  layer.  Finally,  the  resulting  core 
is  cut  into  two  or  more  sections,  according  to 


Fio.   485. — End  of  first  baking;  core  in  two  sections. 

its  size  and  shape,  by  carefully  scratching 
through  the  hard  packed  body  with  a  fine 
point  until  it  is  completely  divided  down  to 
the  platinum. 

With  regard  to  the  colour  of  the  foundation, 
a  very  safe  rule,  especially  for  beginners,  is  to 
have  it  the  same  colour  as  the  rest  of  the  inlay. 
Another  good  plan  is  to  make  the  foundation 
always  white,  and  put  all  the  colour  into  the 
overlying  layer ;   the  advantage  of  this  arrange- 


417 


ment  is  tliat  it  lessens  or  does  away  with  the 
"  shadow  effect  "  of  the  cement  lute.  For 
this  purpose  "  dead  "  white  foundation  body  is 
supplied  by  the  manufacturers,  but  the  same 
effect  may  be  obtained  by  mixing  oxide  of  tin 
with  an  ordinary  translucent  body  of  light 
colour.  Tliompson  and  others,  (juoted  by 
Smreker  (21,  p.  137),  attempt  to  imitate  the 
natural  translucency  of  the  tooth  by  building 
in  layers,  beginning  -i^ith  dark  in  tlie  centre 
and  advancing  to  lighter  on  the  outside,  in 
some  cases  going  .so  far  as  to  put  a  spot  of  red 
in  the  floor  to  in\itate  the  colour  of  the  blood- 
vessels of  the  pulp  shining  tlu'ough. 

The  foundation  is  now  fiixd,  and  it  will  be 
found  that  the  sections  into  which  it  had  been 
cut  liave  contracted,  each  to  its  o^^•n  centre  ; 
the  resulting  chinks  are  now  solidly  filled  with 
the  same  body  as  before,  and  the  completed  core 
fused  to  a  rough  glaze. 

The  matrix  containing  the  core  of  foundation 
is  now  removed  from  the  investment  and  well 
cleaned.  The  easiest  way  to  clean  it,  both  from 
investment  and  from  stray  particles  of  body, 
is  to  soak  it  for  a  few  moments  in  hydrofluoric 
acid,  and  as  this  leaves  a  film  of  insohible 
earthy  fluoride  on  the  surface,  it  may  with  great 
advantage  be  boiled  in  strong  sulphuric  acid 
and  then  \^'ashed  in  plenty  of  plain  water ;  this 
treatment  takes  very  little  time  and  leaves  the 
mould  beautifully  briglit  and  clean  in  the  parts 
free  from  porcelain,  %\hicli  is  itself  roughened  in 
a  manner  that  greatly  helps  the  adhesion  of  the 
next   layer.     The    foil    is,    moreover,    rendered 


over  the  whole  area  of  the  cavity  and  held  by 
the  fingers  of  the  free  hand.  The  matrix  is 
now  removed  from  the  cavity,  the  greatest 
care  being  taken  to  prevent  distortion  of  the 
edge  ;  as  a  rule  it  is  best  to  pack  it  ^^■ith  camphor 
under  the  rubber  strip,  or  if  any  difficulty  is 
likely  to  be  experienced  in  getting  it  out,  it  may 
be  jjacked  with  cement  in  tlie  same  way ;  this 
of  course  holds  the  foil  margin  .so  strongly  that 
it   will   bear   quite  a   lot   of   handling   \\ithout 


-S^J^/i 


Fig.  486. — End  of  second  baking ;  core  complete,  but 
edges  of  matrix  free  from  porcelain.  Matrix  and 
core  are  now  ready  for  trying  in  cavity  and 
reburnishing  of  edges. 

very  pliable  by  the  annealing  it  has  received  in 
the  furnace. 

Tlie  half-finished  inlay  is  now  tried  in  the 
cavity.  A  little  trimming  of  the  surplus  foil 
may  be  necessary,  especially  at  the  side  that 
goes  in  first  and  at  the  cervical  margin ;  there 
is  no  need  to  have  more  surplus  any\\here  than 
is  just  necessary  for  judging  what  cf)ntour  is 
required.  The  foil  is  well  burnished  against 
the  margin  of  the  cavity  so  as  to  get  the  edge 
sharply  defined  without  any  break  in  its  con- 
tinuity. A  final  dead  fit  is  obtained  by  burnish- 
ing with  a  steel  instrument  through  a  double 
fold  of  rubber-dam  which  is  tightly  strained 
14 


F'lO.   487. — Reburnishing    nuuf^iii.,    uf    matri.x    luider 
strip  of  rubber-dam,  after  second  baking. 

distortion.     The  cement  is  removed  by  boiling 
with  a  little  nitric  acid. 

The  matrix  is  now  ready  to  receive  the 
remainder  of  the  porcelain.  The  body  chosen 
should  fuse  at  a  temperature  about  50°  C.  or 
so  below  that  of  the  foundation.  The  tip  and 
base  of  the  tooth  must  generally  be  matched 
separately,  and  the  whole  inlay  made  a  trifle 
dark  for  medial  cavities,  and  light  for  di.stal 
ones.  The  first  layer  after  tlie  tryiiig-in  should 
consist  of  a  thin  coating  round  the  foil  margin, 
great  care  being  taken  in  this,  as  in  all  other 
j  stages,  not  to  get  tlie  slightest  particle  of  body 
over  the  sharp  edge  of  the  cavity.  This  layer 
should  be  fired  to  a  "high  biscuit",  i.  e.  some- 
thing short  of  the  complete  glaze.  The  next 
layer  should  bring  the  porcelain  right  out  to 
its  proper  .shape,  any  surplus  being  carved 
away  so  that  the  sharp  edge  of  the  matrix 
stands  out  the  ^\llole  way  round  as  a  bright, 
slightly  prominent  line.  This  layer  is  also 
fired  to  a  "high  bi.scuit  ".  Some  sliiinkage  will 
have  taken  place,  and  this  mu.st  be  made  right, 
and  the  inlay  fired  to  a  good  glaze,  or,  what  is 
perhaps  a  safer  plan,  brought  to  a  rough  glaze, 
and  the  actual  smooth  surface  obtained  by 
painting  on  a  very  thin  layer  of  body  of  a  still 
lower  fusing  point  and  firing  this  to  a  high 
glaze. 

The  inlay  should  now  be  ready  for  removal 
of  the  matrix,  grooving,  and  setting  in  the 
cavity- 

The  Peck  Method. — The  es.sential  feature  of 
this  method  consists  in  the  fact  tliat  tlie  inside 
dimensions  of  the  matrix  are  equal  to  those  of 
the  ca\'ity  itself.  Consequently,  neither  the 
thickness  of  the  foil  nor  the  presence  of  folds 
in  it  make  any  difference  to  the  fit  of  the  inlay. 


418 


The  use  of  thick  foil  minimizes  the  tendency  to 
warping,  so  that  this  method  is  extremely  useful 
for  making  any  kind  of  inlay  in  -which  A\arping 
is  liable  to  occur,  such  as  those  that  are  shallow 
in  jjroportion  to  their  ai-ea,  and  on  account  of 
the  parallelism  of  their  walls  do  not  permit 
the  use  of  thick  foil  in  the  ordinary  A^ay.  Both 
these  conditions  are  present  in  many  labial 
festoon  cavities  in  which  it  is  very  desirable  to 
place  porcelain  fillings,  and  it  will  be  found  that 
in  these  cases  the  Peck  method  gives  an  accuracy 
and  uniformity  of  fit  that  is  other^vise  very 
difficult  to  obtain. 

Let  it  be  su^jposed  that  the  cavity  has  been 
prepared.  The  matrix  is  swaged  on  to  an 
impression  of  the  cavity ;  this  impression  must 
witlistand  a  good  deal  of  lieavy  pressure  in  the 
course  of  staging,  so  that  cement  is  the  only 
material  both  strong  enough  and  quick-setting 
enough  for  the  purpose. 

To  get  the  impression,  the  cavity  is  first 
vaselined,  and   the   cement  mixed   to   a   thick 


The  Peck  method. 


(A)  The  tooth  cavity. 

(B)  Tile  cement  impression,  fixed  to  the  bed-plate  of  the  press 

(C)  The  foil  matrix  freed  from  cement. 

(D)  The  finished  inlay. 


putty-like  consistency,  and  in  order  to  over- 
come still  further  the  tendency  to  stick  to  the 
dentine,  it  is  rolled  between  the  fingers,  and  the 
surface  made  smooth  with  a  little  French  chalk. 
WliLle  .still  plastic,  it  is  packed  into  the  cavity, 
preferably  in  one  piece,  and  pressed  home  v,ith 
a  little  disc  or  strip  of  metal  large  enough  to 
cover  the  margins  of  the  cavity,  and  if  necessary 
bent  to  the  contour  of  the  tooth  surface.  When 
the  cement  has  set  the  impression  is  gently 
removed,  and  transferred  to  the  bed-plate  of 
the  swaging  press.  It  is  supported  on  and 
fixed  to  tlie  plate  with  cement ;  if  plaster  or 
composition  be  used,  the  impression  \\  ill  ahuo.st 
certainly  crack  in  swaging. 

A  piece  of  foil  is  now  cut  out,  ygVo  inch 
thick  for  small  inlays,  and  -^}ij,  inch  for 
larger  ones.  This  is  first  carefully  fitted  d(n\n 
by  hand.  It  must  be  remembertd  that  the  | 
work  is  being  done  on  a  "  negative  "  of  the 
cavity,  so  that  the  prominent  enamel  margin 
is  represented  by  a  deep  groove,  into  the  bottom 


of  which  the  foil  must  be  taken.  The  fitting 
should  proceed  from  the  centre  outwards,  finish- 
ing up  with  the  groove.  The  thick  foil  rec|uires 
a  certain  amount  of  pressure  to  adapt  it ;  folds 
and  crinkles  are  of  no  consequence  at  all,  as  the 
final  s^\aging  vnil  obliterate  all  traces  of  them 
on  the  inside  of  the  mould.  Burnishers,  and 
pads  of  wool  held  in  the  tweezers,  will  be  found 
the  most  useful  means  of  adapting  the  matrix. 
As  the  fitting  proceeds,  the  surplus  foil  round 
the  edge  may  with  advantage  be  trimmed 
away. 

Opposite  j)laces  where  the  marginal  groove  is 
very  deep  it  is  best  to  trim  the  foil  until  there 
is  hardly  any  surplus  at  all ;  this  ^vill  greatly 
facilitate  the  carrying  of  the  matrix  down  to 
the  bottom  of  the  groove  without  tearing. 
Hand  fitting  should  be  persevered  in  until,  on 
removing  the  matrix,  the  margin  of  the  cavity 
is  well  defined  the  whole  way  round.  It  is 
now  ready  for  SAvagmg ;  this  must  be  very 
thorough,  as  the  smallest  failure  of  adaptation 
of  the  foil  Mill  result  in  making  an  inlay  that 
will  not  go  into  the  cavity  at  all.  The  plate 
carrying  the  impression  and  matrix  is  placed 
in  the  floor  of  the  swaging  press,  and  the  solid 
rul)ber  block,  7iot  the  water-bag,  used 
under  the  iron  plunger.  The  pres- 
sure must  be  very  considerable,  such 
as  that  produced  by  a  large  tail-vice, 
or  a  hydraulic  or  differential  plate- 
swager. 

If  the  pressure  has  been  sufficient, 
the  matrix  will  be  found  absolutely 
adapted  to  the  cement  impression. 
Foil  and  cement  are  removed  to- 
gether from  the  iron  plate  and  boiled 
in  strong  nitric  acid ;  the  acid  dis- 
solves the  cement  and  leaves  the 
matrix  free.  Some  authors  recommend  that 
the  matrix  should  be  detached  from  the  im- 
pression by  the  aid  of  investment  poured  over 
it  and  alloA^'ed  to  set,  or  viith  gutta-percha; 
but  if  the  foil  has  really  been  adapted  well,  both 
these  methods  render  the  matrix  liable  to  fatal 
distortion.  If  the  cement  contains  an  insoluble 
silicious  material,  the  addition  of  a  drop  or  two 
of  hydrofluoric  acid  to  the  nitric  will  soon  make 
it  dissolve.  When  free  from  cement  the  matrix 
is  ready  to  receive  the  porcelain.  It  may  be 
invested  or  not,  as  may  be  most  convenient. 

The  further  stages  are  similar  to  those  of  the 
ordinary  method,  with  the  exception  that  it 
is  impossible  to  try  in  and  re-burnish  when  tlie 
inlay  is  half  finished.  Although  thick  foil  has 
been  used,  no  chance  must  be  given  to  the 
porcelain  to  A\ar))  tlie  matrix,  so  the  body  must 
be  at  once  carried  u])  to  the  cavity  edge  and  the 
mass  well  sectionizrd  for  the  first  baking ;  the 
first  layer  should  also  be  of  a  higher  fusing  point 
than  the  rest  of  the  inlay.     A  little  care  may  be 


419 


necessary  in  removing  the  thick  foO,  especially 
from  a  broad  shallow  piece  of  porcelain ;  the 
best  plan  is  to  loosen  the  matrix  gently  all  round 
the  margin  to  commence  with. 

RETENTION 

This  matter  has  of  necessity  been  alluded  to 
■while  considering  the  preparation  of  the  cavity. 
There  are  two  kinds  of  retention  :  grooving, 
with  or  without  etching ;  and  fixing  with  a 
metal  post,  pin,  or  some  such  means. 

Grooving  and  etching  are  suitable  and  suf- 
ficient for  inlays  that  have  in  cross-sections  ver- 
tical to  the  floor,  an  outline  of  the  Dall  type. 
The  grooves  should  be  in  the  middle  of  the 
lateral  walls,  parallel  to  tlie  surface  and  floor, 
as  narrow  as  they  can  be  made,  and  about  as 
deep  as  their  width.  They  are  most  easily 
made  witli  a  thin  diamond  disc.  They  may  also 
be  made  by  placing  in  a  suitable  position  in 
the  matrix  some  substance  that  can  be  sub- 
sequently removed,  or  is  burnt  out  in  the  firing. 


Fig.  489. — Thin  section  of  porcelain  etched  witli 
hydrofluoric  acid,  showing  the  rough  siu-face 
produced. 

(Magnified   (i   diameters.) 

Such  are  pieces  of  starch,  as  recommended  by 
Le  Cron  (14),  clay,  or  powdered  silica.  Rolls 
of  platimnu  foil,  or  pieces  of  platinum  wire  or 
in  low-fusing  body  gold  foil  or  wire  (or  even 
copper  wire  (21,  p.  297),)  have  been  used  for  the 
same  purpose,  the  metal  being  subsequently 
dissolved  out  with  aqua  regia.  If  the  inlay  is 
being  made  by  the  Peck  method,  the  grooves 
may  be  cut  in  the  sides  of  the  cement  impression, 
and  will  be  accurately  reproduced  in  the  finished 
inlay. 

Besides  grooving,  it  is  well  to  take  advantage 
of  the  additional  lioldfast  given  by  etching  the 
surface  next  to  the  cavity.  This  may  easily  be 
done  by  pouring  a  few  drops  of  strong  hydro- 
fluoric acid  on  the  parts  to  be  roughened ;  the 
outer  surface,  and  a  narro\\'  area  just  inside  the 
edge  all  the  way  round,  should  be  protected 
from  the  action  of  the  acid  by  mdliiuj  a  thin 
layer  of  wax  on  to  them.  After  a  few  minutes, 
according  to  the  strength  of  the  acid,  the  inlav 


is  \\ashed,  the  wax  removed,  and  the  roughened 
surface  made  still  rougher  by  boiling  for  a 
moment  in  strong  sulphuric  acid;  this  is  to 
remove  the  chalky  layer  of  earthy  fluoride  that 
would  otherwise  be  left  on  the  surface.  The 
inlay  is  no^\-  ready  for  drying  and  cementing  in 
the  cavity. 

The  other  method  of  anchorage,  as  aheady 
stated,  is  by  a  metal  post ;  this  may  or  may  not 

A  B 

Fig.  4'JO. 

(A)  Bosch  pin  for  retention  of  inlays. 

(B)  Diagrammatic  section  of  Bosch  pin  in  inlay. 

be  fixed  in  a  special  hole  drilled  in  the  dentine 
for  it. 

If  there  is  no  special  hole  for  the  post,  the 
cavity  must  be  shaped  in  just  the  same  way 
as  if  the  holdfast  consisted  of  etching  and  groov- 
ing only,  but  a  considerable  dei^ression  must  be 
left  on  the  under  side  of  the  inlay  to  contain 
the  metal  anchor  and  the  cement  in  which  it 
holds.  The  post  has  to  l)e  kept  in  place  in  the 
matrix  while  the  body  is  being  packed;  this  is 
most  easily  done  by  making  one  end  of  it  long 
and  sharp,  and  pushing  it  through  the  floor 
of  the  matrix,  so  that  it  holds  in  the  investment, 
the  surplus  length  being  cut  oif  before  the  inlay 
is  fixed  in  the  cavity.  The  cement  space  is 
obtained  by  building  investment  material,  or 
thin  gold  or  platinum  foil,  round  the  part  of 
the  anchor  near  the  floor,  the  other  part  being 
left  free,  so  that  it  is  smrounded  by,  and  solidly 
held  in,  the  porcelain  body. 

Bosch  (15)  has  devised  some  double-headed 
Ijlatinum  pins  for  this  purpose. 

The  part  from  A  to  B  is  pushed  through  the 
floor  of  the  matrix  and  holds  the  pin  in  place 


Fig.  4'Jl. 

(A)  Double-ended  platinum  wire   loop  answering   the 

same  purpose  a~s  Bosch  pin. 

(B)  Section  of  inlay  with  loop  in  situ. 

while  the  body  is  being  packed  ;  when  the  inlay 
is  finished,  it  is  cut  off.  The  part  from  B  to  C 
is  surrounded  by  investment  or  other  material 
during  the  firing,  and  later  on  is  held  in  the 
cement  lute.  Tlie  part  from  C  to  D  is  baked 
into  the  ])orcelain.  A  pin  that  answers  the  same 
purpose  may  be  made  by  bending  a  piece  of 
platmum  wire   in  a  loojj   ^ith   the   two    ends 


420 


projecting,  one  for  fixing  through  the  matrix  and 
the  other  for  holding  in  the  porcelain  body. 

The  fitting  of  a  pin  into  a  hole  specially 
drilled  for  it  affords  a  very  secure  anchorage 
indeed.  The  governing  principle  of  this  kind 
of  anchorage,  and  the  necessary  cavity  pre- 
paration, have  already  been  considered. 

Let  it  be  .supposed  that  the  cavity  has  been 
prepared  and  the  hole  drilled  for  the  post.  An 
impression  is  taken  ^\■itll  the  post  in  position ; 
the  latter  necessarily  comes  away  in  the  im- 
pression and  then  appears  in  its  proper  place  in 
the  cement  model.  To  facilitate  its  removal 
from  the  model  it  should  be  coated  with  a  thin 
layer  of  wax,  and  this  should  be  applied  be/ore 
the  taking  of  the  impression,  the  hole  in  the 
tooth  being  made  sufficiently  easy  to  permit 
this  being  done.  The  pin  is  now  removed  from 
its  hole  in  the  model,  and  the  matrix  fitted  ;  the 
post  is  then  pushed  through  the  floor  of  the 
matrix  into  its  place,  and  the  camphor  packed 
in  as  usual.  Matiix  and  jiost  are  no\\'  removed 
from  the  model,  the  camphor  keeping  them  in 
their  proper  relative  positions ;  they  are  then 
invested,  and  after  the  camphor  has  been 
volatilized  the  post  is  found  firmly  fixed  in  its 
proper  position.  The  core  of  foundation  body 
is  then  made,  fixing  matrix  and  post  together 
with  porcelain,  and  the  inlay  tried  in  and 
finished  in  the  ordinary  way. 

It  has  been  suggested  that  the  pin  should 
be  pushed  through  the  matrix  after  it  is  in- 
vested, and  the  hole  drilled  in  the  tooth  to 
accommodate  the  pin.  If  this  plan  is  adopted, 
it  will  be  found  that  it  is  a  very  difficult  matter 
to  drill  the  hole  in  its  exact  position  ;  in  fact,  the 
attempt  generally  results  in  having  a  hole  much 
too  large  for  the  pin.  In  a  dead  tooth  this  will 
not  matter,  as  there  is  plenty  of  tooth  substance 
to  cut,  and  opportunity  to  have  a  large  and 
strong  post ;  but  in  a  living  tooth,  where  space 
between  the  pulp  and  the  enamel  wall  is  so 
limited,  it  will  generally  be  found  best  to  take 
the  impression  with  the  pin  in  its  place  to 
commence  with. 

If  two  pins  are  required  it  is  well  to  let  their 
ends  join  together  inside  the  porcelain ;  that 
is  to  say,  the  two  pins  should  form  the  two 
ends  of  a  staple.  This  arrangement  greatly 
helps  to  prevent  warping  of  the  porcelain. 
In  cases  that  allow  of  it  the  staple  may  be 
reversed,  so  that  the  two  eyids  are  baked  in  the 
porcelain,  while  the  loop  lies  in  a  groove  cut  in 
the  tooth  to  receive  it. 

FIXING    OF    THE    INLAY 

The  inlay  has  now  been  grooved,  and  its 
underneath  surface  well  etched  with  hydro- 
fluoric acid  to  about  one  millimetre  from  the 
margin. 


As  dryness  is  an  essential  condition  for  the 
adliesion  of  cement,  the  tooth  must  be  satis- 
factorily isolated  from  moisture. 

The  question  now  arises  whether  the  cavity 
shall  be  undercut  or  not. 

It  has  been  stated  by  some  authorities  that 
the  cavity  should  be  left  just  as  it  is,  in  order 
to  ensure  the  accurate  "  keying  "  of  the  inlay 
into  the  tooth  substance.  Head's  researches 
(II),  however,  show  that  cement  is  not  at  its 
be.st  in  a  thin  film,  but  requires  a  certain  thick- 
ness of  substance  to  develop  its  full  strength. 
Moreover,  a  slight  space  under  the  floor  of  the 
inlay  allows  its  margin  to  be  pressed  into  very 
close  apposition  with  the  enamel  edge,  thus 
making  a  better  inlay  and  further  minimizing 
the  chance  of  solution  of  the  cement.  Hence 
a  little  freshening  and  roughening  of  the  surface 
of  the  cavity  is  altogether  an  advantage. 

The  cenient  chosen  should  be  of  fine  grain, 
not  too  cjuick-setting,  and  of  such  a  nature  that 
it  develops  its  full  strength  when  mixed  to  a 
thin  creamy  consistency.  There  are  various 
special  inlay  and  crown  cements  on  the  market, 
which  are  said  by  their  makers  to  possess  these 
properties.  The  colour  may  be  such  as  to 
harmonize  with  that  of  the  inlay,  or  a  white 
cement  may  be  used  for  all  cases,  the  advantage 
of  the  latter  plan  being  that  the  white  ground 
reflects  the  greatest  amount  of  light  without 
changing  the  colour  tone.  In  any  case  of  doubt 
it  is  best  to  try  the  inlay  in  with  some  of  the 
cement  ponder  mixed  with  water,  so  that  the 
actual  effect  may  be  noticed  and  a  powder  of 
different  colour  used  if  necessary. 

The  cement  having  been  chosen,  it  should 
be  mixed  fairly  thin,  and  then  smeared  on  the 
etched  surface  of  the  inlay,  and  over  the  walls 
of  the  cavity.  The  inlay  is  now  placed  in  the 
cavity  and  pressed  gently  and  firmly  into  its 
correct  position,  especial  care  being  taken  to 
avoid  any  tilting,  \\'hich  Mould  make  one  edge 
too  high  and  the  opposite  one  too  low,  and  so 
spoil  the  whole  fit  of  the  fillini;.  If  the  cavity 
has  been  properly  prepared,  this  accident  is  not 
very  likely  to  happen.  In  approximal  cavities 
it  is  best  to  tie  the  inlay  in  place  while  the 
cement  is  hardening. 

After  the  cement  has  thoroughly  set,  the 
exce.ss  is  removed.  If  fitted  as  it  can  quite  well 
be  fitted,  the  inlay  itself  .should  not  require 
either  dressing  down  or  polishing  of  any  kind. 
If  the  edge  projects  above  the  level  of  the 
enamel,  it  is  a  sign  of  faulty  workman.ship,  either 
in  making  the  inlay  or  in  cementing  it  into 
place. 

COMBINATION    FILLINGS 

Some  difficult  cavities  are  most  easily  treated 
by  filling  each  half  of  them  separately. 

Both  fillings  may  in  some  cases  be  made  of 


421 


porcelain.  This  can  be  done  by  first  filling  one 
half  of  the  cavity  with  cement  or  artificial 
dentine,  then  making  and  fixing  an  inlay  in 
the  other  part,  and  finally  cutting  the  temporary 
filling  away  and  making  the  inlay  for  the  second 
half.  As  a  rule  it  is  only  necessary  to  put 
porcelain  in  the  half  that  shows  most.  The 
other  half  ^\ould  in  these  cases  be  filled  ^\ith 
amalgam  or  gold  before  the  preparation  of  the 
rest  of  the  cavity  for  the  inlay.  Gold  and 
porcelain  inlays  may  be  combined  in  this 
way,  the  gold  inlay  being  made  and  fixed 
first. 

CJold  and  porcelain  can  also  be  joined  together 
and  cemented  into  the  tooth  as  one  mass.  There 
are  two  ways  of  doing  this. 

In  the  first  method  a  wax  foi'm  is  made  for 
the  whole  cavity,  but  before  casting,  a  portion 
of  the  wax  is  removed  from  the  labial  surface, 
so  as  to  make  a  depression  in  the  finished 
inlay,  care  being  taken  to  preserve  the  rim  of  the 
mould  intact.  The  resulting  depression  in  the 
cast  gold  inlay  is  filled  ^\  ith  low  -fusing  body,  so 
that  nothing  of  the  gold  is  visible  but  the  fine 
line  at  the  edge. 

By  the  other  method  the  porcelain  inlay  is 
made  first ;  the  side  of  it  that  fits  against  the 
gold  is  then  cut  into  a  dovetail,  and  the  inlay 
put  into  its  place  in  the  cavity.  The  renu\ining 
part  of  the  space  is  then  filled  with  casting  wax  ; 
porcelain  and  wax  are  removed  together  and 
invested,  and  the  gold  is  cast  in  the  ordinary 
manner.  The  gold  runs  into  the  dovetails  of 
the  porcelain,  and  the  two  form  one  solid  mass, 
which  is  then  groo\ed  for  retention  and  cemented 
like  anv  other  inlav. 

J.  B.  P. 


(1 

(2, 

(3 

(4 
(5 

(6: 

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(8 

(9 

(10 

(11 
(12 

(13 
(14 

(15 

(16 

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(18: 
(19 

(20 
(21 

(22 

(23 


BIBLIOGRAPHY 

Bluell.     Dental  Cosmos,  1910,  Vol.  LIl,  p.  84. 
BYR.4M,      J.      Plienoinena     observed     in     fusing 

Porcelain.     Dental  Review,  1906,  pp.   223,  338. 
Capon,   W.  A.     Porcelain   after   Eighteen  Years. 

Dental  Cosmos.  Sept.   1008,  Vol.  L,  p.  909. 
Custer,  L,  E.     Construction  of  Electric  Furnaces, 

Dental  Rciueic,  1906,  p,  878. 
FiCEES,  W.  h.     Chemical  and  Physical  Character- 
istics   of    Porcelain    and    their   Relation   to  its 

Manipulation.     Dental  Cosmos,    1910,  Vol.  LIT, 

p.  48. 
Garhart,    W.  E.     Construction  of  Electric  Fur- 
naces.    Dental  Review,  1906,  p.  891. 
GuTTMANN,  A,     Progrls  Dentaire,   1904,  pp.  257, 

326. 
Hammond,  J,  F.      Construction  of  Electric  Fur- 
naces,    Dental  Review,  1906,  p.  883, 
Head,     Strength    of   Porcelain,     Dental  Cosmos, 

1906,  Vol,  XLVIU,  p,  130, 
He.\d,     Tests    on    tlie    Inlay    Cement    Problem. 

Dental  Cosmos,  1905,  VoLXLVlI,  p,  775, 
Head,     Dental  Cosmos,  1908,  Vol,  L,  p,  812, 
Jeffery,  L,     Duplex  Inlays,     Brit.  Dent.  Jour., 

1904,  Vol,  XXV,  p,  767, 
Jenkins,    Dental  Cosmos,  1902,  Vol.  XLIV,  p,  456, 
Le  Cron,     Porcelain  Work.     Published  by  Dental 

Manufacturing  Co,,  Ltd. 
Machwurth,     Porcellanfiillung  mit  Platinstiften, 

Deutsche  ilonatsschrijt  fur  Zahnheilkunde,  1902, 

p,  531, 
McCuxLOUGH.     Dental     Cosmos,     190(>-7,     Vols, 

XLVIII-XLIX.  p,   143, 
PouNDSTONE,     Tile  Cement  Problem  in  Porcelain 

Work,     DcntM  Cosmos,  1904,  Vol,  XLVI,  p,  760, 
Price,  Weston  A,     Dental  Brie),  1904,  p,  136, 
RoBBiNS,   C,     Aji   Improved  Porcelain  Inlay  Tip, 

Brit.    Dent.    Jour.,     1907-8,      Vols,    XXVIU  - 

XXIX,  p,    611, 
Robin,  Pierre,     Progri's  Dentaire,  1901,  p.  257. 
Smreker,  E,     Handbiich  der  Porzellan/ idlang  und 

Goldcinlagen. 
Underwood,    A,   S,       Trans.    Odont.    Soc,    April 

1904,  p,  179, 
Wheeler,     Dental    Cosmos,     1904,    Vol,    XLVI, 

p,  547, 


CHAPTER  XXV 

GOLD  INLAYS 


Treatment  of  caries,  or  restoration  of  lost 
portions  of  teeth,  by  inlaying  gold  is  not  alto- 
gether new  (13).  Gold  inlays  were  made  as 
early  as  1868,  notably  by  the  late  Dr.  Swazey 
of  Chicago,  whose  work  was  found  in  good 
condition  in  teeth  of  his  patients  more  than 
thirty  years  afterwards.  The  durability  of 
inlaid  fillings  cannot  therefore  be  regarded  as 
untried  (6). 

In  respect  of  technique  the  gold  inlay  is  yet 
in  the  developmental  stage.  Inlay  technique 
in  use  prior  to  the  advent  of  pressure  casting  is 
now  abandoned,  and  even  the  technique  of  the 
latter  process  has  undergone  many  variations 
since  its  introduction.  Hence  any  description 
of  technical  jirocedure  written  now  may  soon 
become  obsolete  by  reason  of  further  change 
or  improvement.  Pressure  casting  renders  prac- 
ticable certain  changes  in  tlie  interior  form  of  an 
important  class  of  cavities,  and  these  changes 
tend  to  enlarge  the  limits  within  M'hich  gold 
inlays  may  be  used. 

The  advantages  of  the  cast  inlay  over  the 
large  or  complex  foil  fillmg  may  be  briefly 
stated  as  follows  :  The  inlay  lessens  the  work 
to  be  done  in  the  mouth ;  better  protects  frail 
walls  against  wear  or  fracture ;  restores  projjer 
contour  and  contact  ^vith  more  certainty ; 
lessens  pain  by  the  form  and  manner  of  cavity 
preparation  in  Hve  teeth ;  and  minimizes  waste 
of  tissue  and  encroachment  upon  the  region  of 
the  pulp,  more  especially  in  buccal,  lingual, 
and  gingival  extension  of  cavity  margins  to 
areas  of  comparative  immunity.  It  minimizes 
irritation  of  live  dentine  or  pulp  by  inter- 
position of  cement.  It  renders  the  rubber-dam, 
with  its  clamps  and  ligatures,  unnecessary.  It  is 
inserted  without  the  irritation  of  the  periodontal 
membrane  incident  to  the  condensation  of  foil. 
By  the  use  of  suitably  alloyed  gold  the  cast 
inlay  is  harder,  stronger,  and  less  conspicuous, 
by  reason  of  colour,  than  is  the  foil  filling.  The 
comparative  advantages  of  the  inlay  do  not, 
however,  hold  good  for  all  cavities,  but  only  for 
the  larger  or  more  complex  kinds  hereafter 
described.  Generally  speaking,  the  smaller  and 
simpler  the  cavity  the  less  will  be  the  advantage 
of  the  inlay  (12).  Wliile  it  is  trae  that 
gold  inlays  are  made  more  accurately  and 
easily  by  casting  than  they  were  by  any  other 
method,  it  does  not  follow  that  less  knowledge, 


422 


skill,  or  attention  to  detail  wUl  suffice  to  attain 
the  desired  results. 

Dimension  Changes  in  Gold  Investments  and 
Wax. — The  follo\\ing  statements  of  dimension 
changes  occurring  in  gold  or  accessories  in 
process  of  casting  are  derived  from  Weston  A. 
Price's  report  of  his  investigation  recently 
published  in  the  Dental  Cosmos.  As  sf)ace 
allows  only  brief  mention  of  these  important 
matters  here,  the  reader  is  referred  to  Price's 
interesting  account  of  the  newly  discovered 
properties  of  these  materials,  and  the  principles 
upon  which  errors  in  practical  results  are  to  be 
avoided  (23). 

No  process  now  in  use  yields  gold  castings 
that  exactly  fit  all  jsarts  of  the  cavities  they 
are  made  for.  Gold,  whether  alloyed  or  not, 
contracts  upon  solidification  and  cooling. 
According  to  Price's  figures  the  total  linear 
contraction  of  24-carat  gold  in  passing  from 
the  liquid  state  to  0°  C.  is  -0384,  or  3-84  per 
cent;  contraction  in  change  of  state  is  r64 
per  cent,  and  in  cooling  2'20  per  cent.  This 
contraction,  though  not  preventable  by  any 
means  no^\'  known,  may  be  off-set,  compensated, 
or  controlled,  so  as  to  lessen  or  minimize  the 
errors  in  fit  otherwise  inevitable  in  a  cast  inlay 
of  complex  form  (19). 

Off-set  is  here  used  to  mean  expansion  or 
enlargement  of  the  mould,  as  by  crystallization 
or  heating,  so  that  the  molten  metal  is  introduced 
while  cxjjansion  of  the  mould  is  greatest.  The 
expansion  available  in  the  best  moulds  at  pre- 
sent is  effected  by  heating,  and  is  generally 
equal  to  less  than  one-third  of  the  contraction 
of  gold. 

By  compensation  is  meant  the  effect  of  sus- 
tained pressure  upon  the  molten  gold  in  the 
mould.  As  solidification  is  not  instantaneous 
but  gradual,  and  accompanied  by  contraction, 
additional  metal  is  forced  into  the  mould  by 
pressure  upon  the  surjilus  in  the  gate.  In 
other  Mords,  sustained  pressure  keeps  the  mould 
full  until  the  metal  becomes  so  solid  as  to  resist 
the  pressure  used,  the  inevitable  contraction 
occurring  in  the  sprue  more  than  in  the  casting. 
The  greater  the  pressiu'e,  the  larger  is  the  fraction 
of  total  contraction  of  the  casting  compensated 
for.  The  contraction  of  a  gold  casting  is 
reduced  to  "013  or  1'3  per  cent  by  an  effective 
pressure  of  five  and  a  half  pounds  per  square 


423 


1^  incli  upon  the  casting,  as  developed  in  a  centri- 
fugal machine  (19). 

The  direction  of  contraction  can  be  to  some 
extent  controlled.  Such  control  depends  upon 
the  figure  of  the  casting,  the  hardness  of  certain 
parts  of  the  mould,  and  the  contractile  strength 
of  the  metal.  If  a  band  of  gold  is  cast  iipon  a 
hard  stone  core,  contraction  of  the  gold  in  one 
direction  is  ojjposed  or  ^^'ithstood  by  the  core, 
and  does  not  lessen  the  inside  diameter  of  the 
band ;  the  contraction  of  the  gold  takes  place 
in  directions  where  it  is  unopposed,  making  the 
band  narrower  and  thimier.  This  kind  of 
control  has  a  useful  application  in  casting  an 
inlay  to  fit  two  or  more  surfaces  of  a  tooth.  A 
hard  stone  model,  by  holding  the  cooling  gold, 
maintains  certain  inside  dimensions  of  the  inlay 
that  are  essential  to  its  fitting  the  cavity ;  hence 
effectiveness  of  control  may  depend  upon 
cavity  preparation  and  consequent  shape  of  the 
inlay.  Complex  ca\aties  should  therefore  be 
prepared  ^\'ith  due  regard  for  the  control  of 
contraction  and  the  consequent  transfer  of  its 
effects  to  parts  where  they  do  no  harm  (20). 

Off-set,  comi)ensation,  and  control,  may  all  be 
used  at  once  in  casting  complex  inlays.  Their 
combined  effect,  with  present  facilities,  wOl  be 
equal  to  less  than  the  total  contraction  of  gold, 
plus  the  contraction  of  wax  impression  or  model. 

Investment  Materials. — Expansion  or  con- 
traction of  any  investment  now  in  use  varies 
with  the  temperature  to  which  it  is  heated. 
The  investment  mixtures  supplied  by  dealers 
differ  froni  one  another  in  the  extent  to  which 
they  contract  or  expand  when  heated,  and  also 
in  the  temperature  at  which  maximum  expansion 
or  contraction  occurs.  In  the  best  investment 
tested  by  Price  a  maximum  expansion  of  "0085 
was  reached  at  1000°  F. ;  in  others  the  maximum 
expansions  were  much  less  and  occurred  at 
loM'er  temperatures  ;  in  some  contraction  began 
at  900°.  After  reaching  a  temperature  of  1000° 
and  cooling  to  ordinary  temperature,  all  con- 
tracted to  an  extent  var\dng  from  -005  to  '035 
of  their  original  linear  dimensions  when  set. 
If  heated  to  burn  out  the  wax  and  then  cooled 
before  casting,  a  mould  made  of  such  an  in- 
vestment \\\\\  contract,  increasing  the  errors  in 
dimension  due  to  contraction  of  the  gold ;  the 
mould  sliould  therefore  not  be  allowed  to  cool 
before  casting,  which  should  be  done  at  the 
temperature  of  maximum  expansion  (21). 

Wax. — The  volume  of  any  wax  varies  with 
its  temperature.  "  The  rate  of  expansion  of 
all  waxes  changes  rapidly  with  increase  of 
temperature,  but  at  different  rates  for  different 
base  waxes  and  different  formulae  of  mixtures." 
Inlay  waxes  for  use  in  making  models  or  jiatterns 
are  composed  of  base  waxes  according  to  different 
formulae.  These  differ  from  one  another  in  the 
maximum  and  minimum  temperatures  at  which 


they  are  M'orkable,  and  also  in  the  degree  to 
^^'hich  they  contract  in  cooling  from  lowest 
working  temperature  to  room  temperature,  or 
67°  F.  The  linear  contractions  recorded  within 
these  limits  of  temperature  vary,  for  the  ^^'axes 
tested,  from  Tl  to  2-3  per  cent.  A  wax  model 
prepared  in  the  mouth  and  chilled  for  removal 
will  at  67°  F.  have  linear  dimensions  from  1-1 
to  2'3  per  cent  (according  to  the  wax  used)  less 
than  the  dimensions  of  the  cavity  in  which  it 
was  made.  If  invested  at  67°  or  a  lower 
temperature  the  error  in  dimensions  will  be 
carried  forward.  If  left  uninvested  for  several 
hours  in  a  warm  room,  or  warmed  to  or  near  its 
lowest  working  temperature  for  expansion,  the 
model  will  be  distorted.  Distortion  cannot  be 
corrected  by  a  subsequent  step. 

Inlay  waxes  have  considerable  elasticity. 
Stretched,  compressed,  or  bent,  while  warm, 
and  then  chilled,  tliey  retain  the  new  form  only 
•\\hile  kept  cold  ;  if  warmed  they  tend  to  resume 
original  form ;  stretched  parts  shorten,  com- 
pressed parts  expand,  and  bent  parts  tend  to 
straighten,  ^\•hile  the  volume  of  the  wax  in- 
creases M'ith  rising  temperature.  For  im- 
pressions, as  distinguished  from  models,  a  wax 
may  be  used  having  only  half  the  contraction  of 
the  best  model  ■\\-ax,  or  0'6  per  cent  linear,  and 
less  than  one-fourth  the  elasticity  of  inlay  waxes. 

Cement. — Cement  exposed  to  the  fluids  of  the 
mouth  disintegrates ;  the  greater  the  area 
exposed,  the  thinner  the  mix  of  cement,  or 
the  nearer  the  exposure  to  the  gum  margin, 
the  more  rapid  will  solution  or  ^\■asting  be.  The 
quality  of  the  cement,  its  manipulation,  or  the 
character  of  the  oral  fluids,  may  one  or  all  hasten 
or  delay  solution ;  but  the  general  experience 
of  the  dental  profession  ^Aith  cements  seems  to 
warrant  the  caution  to  treat  them  all  as  soluble 
in  the  fluids  of  the  mouth.  For  this  reason  the 
margins  of  all  gold  inlays  must  fit  so  closely  to 
the  prepared  enamel  as  to  exclude  oral  fluids 
from  contact  with  the  cement  (26)  (30). 

Qualities  of  Metals  for  Inlay  Casting. — Ideal 
alloys  for  inlay  castings  have  not,  so  far  as  is 
known,  been  produced  ;  that  such  alloys  will  be 
developed  does  not,  however,  seem  impossible. 
The  qualities  desirable  in  metals  for  this  use 
are- — 

Malleability,  strength,  and  hardness,  varying 
from  tliat  of  pure  gold  to  about  that  of  an 
alloy  composed  of  ninety-five  parts  gold 
and  five  parts  coin  silver,  to  satisfy  the 
needs  of  various  situations. 

Immunity  from  chemical  attack  or  change  in 
the  mouth,  as  complete  as  that  of  pure 
gold. 

Contraction  upon  solidification  and  cooling 
to  an  extent  of  one-third  that  of  gold,  or 
about  one  per  cent. 


424 


Colour,  that  of  a  white  metal  or  alloy  that 
would  be  inconspicuous  in  the  mouth. 

Conductivity,  electrical  or  thermal,  the 
minimum. 

Especially  undesirable  qualities  are  brittleness 
and  elasticity. 

Pure  or  24-carat  gold,  by  reason  of  its 
malleability  and  softness,  is  easily  moulded 
or  burnished  to  close  contact  \^ith  cavity 
margins.  Exposed  to  stress  on  incisal  angles 
or  marginal  ridges,  however,  it  is  too  soft,  and 
is  ajjt  to  spread  or  .stretch  so  as  to  fail  where  the 
bite  is  strong.  Reinforcement  is  suggested  by 
Price  as  a  remedy  for  this.  Small  threaded 
platino-iridium  wire  bent  to  the  form  of  the 
letter  L  is  j)laced  in  the  cavity  of  the  stone 
model  before  waxing,  so  that  the  gold  when  cast 
will  enclose  it.  The  wire  strengthens  parts 
otherwise  lial)le  to  stretching  oi'  bending,  and 
also  restrains  contraction  along  the  wire,  without 
changing  the  mouklable  qualities  of  the  inlay 
at  the  margins  (21).  For  inlays  not  exj)osed  to 
stress,  or  those  surrounded  by  strong  walls,  as 
in  buccal  or  some  occlusal  cavities  of  molars, 
pure  gold  is  best  a,i\d  needs  no  reinforcement. 

The  addition  of  five  per  cent  of  either  platinum 
or  coin  silver  to  gold  gives  it  strength  and  hard- 
ness equal  to  the  needs  of  almost  any  situation 
without  rendering  it  too  hard  for  burnishing. 
The  harder  the  metal  in  an  inlay,  the  thinner 
its  edges  should  I)e  to  allow  effective  burnish- 
ing; and  the  liarder  the  alloy  of  gold,  the 
greater  are  the  difficulties  due  to  shrinkage  or 
to  .slight  inaccuracies  in  technique.  Therefore, 
thick  or  bulky  inlays,  if  made  at  all,  .should  not 
be  made  of  hard  metal  (32). 

Inlays  that  are  to  support  ends  of  bridges 
should  be  of  alloyed  gold,  or  else  reinforced  with 
wire.  But  no  alloy  to  be  used  for  an  inlay 
should  be  harder  than  the  situation  requires. 
The  harder  the  gold,  the  more  elastic  it  is  and 
the  less  effectively  burnished  ;  an  edge  of  elastic 
metal  pi-essed  against  the  enamel  %\'ith  a 
burnisher  tends  to  return  or  spring  away, 
leaving  the  joint  imperfectly  closed.  Scraps 
containing  .solder,  or  zinc,  or  any  ba.se  metal 
should  nut  be  added  to  inlay  gold. 

Special  Instruments. — For  preparation  of 
inlay  cavities,  abrasives,  where  they  can  be  used, 
are  superior  to  steel  cutting  instruments. 
Especially  useful  are  thin  steel  discs  charged 
upon  one  side  with  carborundum ;  these  can 
be  used  upon  an  approximal  surface  without 
injury  to  the  adjacent  tooth.  "  Vulcarbo  "  discs 
are  excellent  for  their  rapid  cutting  qualities ; 
these  and  the  charged  metal  discs  are  to  be 
preferred  for  their  thinness.  Small  square- 
edge  wheels  and  cones  should  be  of  vitrified 
carborundum  ■ 

Abrasives  cut  with  less  irritation  and  vibra- 


tory jar  than  burrs  do.  Enamel  margins  cut 
with  abrasives  are  stronger  against  attack  of 
any  kind  than  when  cut  with  steel  instruments, 
as  will  be  obvious  upon  consideration  of  the 
.structure  of  enamel  (29).  The  friction  of  any 
rotary  cutter  used  dry  rapidly  generates  heat, 
which  is  largely,  sometimes  wholly,  responsible 
for  the  pain  suffered.  Therefore,  water  should 
be  applied  to  minimize  frictional  heat  and  keep 
the  cutter  clean  for  rapid  progress ;  a  medicine 
dropper  held  in  the  left  hanel  will  conveniently 
supply  A\'ater  for  this  purpose. 

CAVITIES    SUITABLE    FOR    GOLD    INLAYS 

(1)  Approximal  cavities  in  meilars  and  pre- 
molars that  involve  the  contact  point.  Science 
and  experience  both  teach  that  the  occlusal 
surface  is  the  proper  place  for  the  fillings  of 
these  cavities  to  terminate  at,  whether  it  is 
carious  or  not.  These  cavities,  and  tho.se  in 
whicli  the  occlusal  surface  also  is  carious,  "will 
be  treateel  as  approximo-occlusal. 

(2)  Occlusal  cavities  extending  to  buccal  or 
lingual  surfaces,  or  other^xise  so  large  as  to 
render  any  wall  weak  or  unsafe  for  foil  filling. 

(3)  Any  large  portion  of  tooth-crown  lost  by 
fracture,  abrasion,  or  caries,  where  an  artificial 
crown  is  not  indicated,  and  exposure  to  view  or 
to  stress  contra-indicatcs  amalgam  or  porcelain. 

(4)  Certain  buccal  ca\'ities  in  molars  or  pre- 
molars. 

(5)  Certain  approximal  cavities  in  incisors  or 
canines  involving  the  incisal  angle,  or  the  pulp, 
or  both,  especially  where  the  fillings  are  exposed 
to  stress,  anel  aesthetic  considerations  are  not 
paramount. 

(6)  Cavities  in  molars  or  premolars  in  which 
death  of  the  pulp  has  occurred. 

Special  Requirements  in  the  Preparation  of 
Cavities  for  Gold  Inlays. — According  to  current 
teacliing  cavdties  for  gold  inlays  are  prepared  in 
much  the  same  way  as  for  foil,  but  \\ithout 
undercuts  or  convenience  points  (2).  This 
teaching  needs  amendment  in  so  far  only  as  it 
relates  to  complex  cavities :  a  cast  inlay  of 
complex  form  differs  from  the  corresponding 
foil  filling  in  tensile  strength,  retention,  manner 
of  insertion,  and  form  necessary  for  resisting 
stress  (3). 

Gold  alloyed  with  five  per  cent  of  platinum 
or  coin  silver,  or  reinforced  with  platino- 
iridium  wire,  and  ca.st  under  high  pressure,  is 
stronger  in  all  ^^•ays  than  a  foil  filling  of  like  size 
and  form.  The  interior  dimensions  of  a  cavity 
may,  so  far  as  the  strength  of  the  filling  itself 
is  concerned,  be  smaller  for  an  inlay  than  for 
foil.  Certain  interior  dimensions  and  form  of 
cavity  that  are  not  necessary  for  the  insertion 
of  an  iiday  are  necessary  for  the  insertion  of 
foil. 


425 


To  withstand  masticatory  stress  approximo- 
occlusal  foil  fillings  require  as  a  foundation  a 
broad  flat  gingival  ^^■all  at  right  angles  ^\ith  the 
tooth's  axis,  and  need  a  dovetailed  step,  or 
occlusal  portion,  as  a  brace.  An  inlay,  on  the 
other  hand,  being  a  single  rigid  piece,  is  supported 
by  the  whole  area  covered  by  it ;  its  hook-like 
hold  in  the  occlusal  portion  of  the  cavity  is 
much  stronger  than  that  of  a  foil  filling,  so  that 
unless   much   dentine  is   lost    by   caries,   little 


Fig.  492. 


gingival  wall  is  needed  to  supjaort  the  inlay 
against  occlusal  stress.  \Vlien  the  dentine 
underlying  a  marginal  ridge  is  not  destroyed  by 
caries,  it  is  obvious  that  broad  or  deep  cutting 


Fig.   4'J3. 

of  the  approximal  part  of  the  cavity  only  trans- 
fers so  much  stress-resisting  area  from  the  step  to 
the  gingival  wall.  \\'ithoiit  at  all  increasing  tlie 
support  of  the  inlav.  Much  is  lost  by  such 
14* 


cutting  for  an  inlaj',  however  necessary  it  may 
be  for  other  fillings,  and  nothing  is  gained 
except  convenience  in  preparing  the  wax  model 
in  the  mouth,  an  object  likely  to  be  abandoned. 


Fig.   4<J4. 


Sufficient  retention  for  the  cast  inlay  is  secured 
without  broad  or  deep  rectangular  preparation 
of  the  approximal  part  of  the  cavity.  Too  much 
cutting  for  retention  is  worse  tlian  too  little,  for 


besides  the  pain  occasioned  the  strength  of  the 
tooth  is  endangered,  and  the  difficulty  of  secur- 
ing satisfactory  fit  of  the  inlay  is  increased 
by  needless  addition  to  its  mass.  Insufficient 
retention,  on  the  other  hand,  allo\\s  the  inlaj' 
to  leave  the  cavity  the  moment  its  usefulness 
has  ceased ;  the  occurrence  is  known  to  the 
patient  and  the  remedy  is  simi^le  (36). 

Thill  edges  of  a  cast  inlay  can  be  extended  for 


426 


any  desired  distance  beyond  the  necessarily 
deep  parts  of  the  cavity.  Therefore,  extension 
of  cavity  outlines  to  immune  areas  does  not 
require  corresj)onding  extension  of  parts  de- 
signed for  retention  or  resistance.     For  these 


Fig.   49G. 

reasons  cavity  preparation  may  be  more  simple 
and  less  wasteful  for  the  cast  inlay  than  for  any 
other  filling. 

The  same  considerations  govern  outline  form 
of  inlay  as  of  other  fillings.  Any 
special  difference  will  be  to  allow 
withdrawal  of  impression,  or  more 
amply  to  protect  frail  walls  on  the 
occlusal  surface  than  other  fillings 
can  be  made  to  do.  For  all  inlays 
exposed  to  stress  the  cavities 
should  have  such  form  as  will 
lock  the  inlay,  independently  of 
cement,  against  movement  caused 
by  application  of  that  stress. 

The  fgures  are  intended  to 
show  cavity  preparation  in  which 
these  requirements  are  fulfilled 
in  the  several  classes  of  teeth. 

The  margins  of  inlay  cavities 
should  at  all  points  be  bevelled  so 
widely  that  contraction  in  casting 
cannot  cause  the  margin  of  the 
inlay  to  fall  short  of  the  margin  of 
the  cavity  at  any  point  when  the 
inlay  is  in  place.  Figs.  493  and 
494  show  the  results  of  failure  to  bevel  the 
gingival  margins.  Fig.  492  shows  a  bevel  that  is 
insufficient  for  an  inlay  of  that  form  if  made  of 
alloyed  gold;  half  the  overlap  is  removed  to 
show  that  the  body  does  not  reach  the  gingival 


wall.  The  other  figures,  except  504,  show  the 
advantages  of  preparation  that  allows  the  inlay 
to  terminate  iji  knife-edge  margins  overlapping 
prepared  enamel  (21). 

An  inlay  cavity  must  have  such  form  that 
impression  or  model  can  be 
withdrawal  in  one  direction 
from  it  without  mutilation ; 
and  the  direction  of  with- 
dra\\al  should  be  opposite  to 
that  from  which  the  stress  of 
mastication  comes. 

AVliere  caries  is  extensive, 

as  in  many  of  the  specimens 

illustrated,  the  first  measure 

of  preparation  after  removal 

of  debris  should  be  the  filling 

of    the    cavity    with    a    soft 

cement    easUy    cut    without 

damage  to  instruments.  With 

discs  and  water  the  approxi- 

mal  surface  should  be  cut  flat, 

,  .  cement  and  enamel  together. 

'^^^^iS  The  facet  so  prepared  should 

■PI^^^P  extend     gmgivally    a     little 

^^^^■^  beyond  the  gum  margin,  and 

bucco-lmgually    to    immune 

areas  or  sound  enamel.     The 

plane  of  this  facet  may  incline 

slightly  towards  the  long  axis 

of  the  tooth  occlusally  where  necessary,  to  allow 

withdrawal  of  impression,  or  to  terminate  the 

facet  gingivally  without  a  step. 

Where  dentine  is  destroyed  upon  the  approxi- 


mal  aspect,  as  in  Fig.  501 ,  a  groove  parallel  to  the 
axis  of  the  tooth  may  be  cut  in  the  cement  with 
an  inlay  burr,  reaching  as  far  as  the  dentine,  or 
the  amalgam  preparation  at  the  gingival  wall 
elsewhere   described,   to   afford   direct   support 


427 


against  occlusal  stress,  in  addition  to  that 
always  provided  in  the  occlusal  portion,  and  by 
the  underlying  cement  elsewhere.  The  gingival 
end  of  this  groove  should  mark  the  termination 
of  caries,  and  serve  for  guidance  in  making  the 
proper  extension  of  gold  beyond  this  point 
to  fit  the  bevelled  margin  of  the  cavity. 
This  interior  form  of  inlay  is  favourable  to 
firm  attachment  of  cement. 

It  \\ill  be  found  that  flattening  an 
approximal  surface  of  almost  any  molar  or 
premolar  to  the  extent  specified,  will  allow, 
in  restoration  of  contour,  a  sufficient  body 
of  alloyed  or  reinforced  gold  to  meet  all  the 
needs  of  the  situation.  The  edges  of  an 
inlay  fittmg  cavity  margins  of  this  form  are 
thin,  and  easil}'  burnished  to  close  contact 
with  the  prejiared  enamel,  if  the  gold  be 
not  too  hard  or  elastic. 

Occlusal  steps  or  grooves  are  cut  with 
square-edge  wheels  of  suitable  thickness 
and  diameter,  finished  where  necessary 
with  square-end  fissure-burrs,  and  bevelled 
with  bevel-edge  wheels  or  conical  points. 
An  occlusal  pit  or  dovetail  is  preimred 
preferably  at  the  termination  of  the  step 
by  means  of  an  enamel  drUl,  and  finished 
with  an  inlay  burr  in  a  natural  groove  or 
pit  where  little  waste  of  tissue  is  incurred. 

To  prepare  such  incisor  cavities  as  in  Figs.  506, 
508  and  511,  involving  as  they  do  the  puljJ  and 
the  incisal  angle,  fill  the  cavity  to  excess  with 
cement,  and  dress  with  a  disc  to  form  a  convexity, 


form  of  inlay.  In  such  a  form  as  in  Fig.  504, 
where  a  thick  body  of  metal  enters  the  cavity 
and  extends  upon  the  incisal  edge,  slight  errors 
of  dimension  in  the  ca.sting  will  make  closure 
of  joints  difficult  or  impossible,  unless  unpre- 


4'JS. 


providing  for  an  inlay  that  is  concave  upon  its 
cavity  aspect  and  terminates  in  a  knife  edge  at 
all  margins.  Such  a  form  allows  perfect  closure 
of  the  entire  joint  by  burnishing,  and  is  quite  as 
easily  made  upon  the  stone  model  as  any  other 


Fig.  4yy. 

pared  enamel  is  overlapped  by  a  feather  edge 
of  metal.  The  thickness  of  this  inlay,  if  of 
alloyed  gold,  is  far  in  excess  of  the  need,  and 
out  of  proportion  to  the  strength  of  cavity 
walls.  Thick  bodies  of  metal  and 
butt-joints  or  abrupt  termination, 
seen  also  in  Figs.  493  and  494,  are 
difficult  terminations  to  manage. 
They  are  rendered  ill-fitting  by 
-flight  errors  in  dimension  due  to 
I  ontraction  of  wax  model,  invest- 
ment, or  gold,  so  that  the  joints 
'•annot  be  closed  by  liurnishing. 

Cavity  forms  in  Figs.  496  to 
"ill,  except  504,  were  recently 
designed  to  avoid  or  lessen  errors 
due  to  the  part  of  contraction  not 
I  orrected,  and  to  render  small  and 
unavoidable  inaccuracies  practi- 
cally harmless.  These  forms  are 
found  in  practical  use  to  have 
other  advantages;  they  are  pre- 
pared more  easily  and  less  pain- 
fully, waste  less  tooth  tissue,  keep 
the  metal  farther  from  the  pulp, 
and  yield  an  accurate  impression 
more  easDy  than  do  the  deeper 
cavities  now  generally  in  use.  Some  advan- 
tages of  this  preparation  are  seen  by  compari- 
son of  Fig.  493  with  Fig.  497,  each  being 
the  medial  surface  of  a  right  upj^er  molar.  In 
Fig.  497,  buccal,  lingual,  and  gingival  extension 


428 


to  immune  areas  is  secured  by  very  little 
cutting  of  surface  enamel,  and  no  dentine  is 
cut.  The  inlay  is  wider  at  the  gingival  than  at 
the  marginal  ridge,  and  no  tissue  is  cut  except 


Fi., 


for  retention,  resistance,  and  extension  to 
immune  areas.  In  Fig.  493,  the  cavity  was 
prepared  upon  the  assumption  that  a  stress- 
resisting   gingival   wall   is   necessary.     Because 


Fk;.    0(11. 

a  molar  decreases  in  medio-distal  diameter 
towards  its  neck,  bucco-lingual  extension  to 
immune  areas  in  that  region  necessitates  the 
wide  cutting  seen  at  the  marginal  ridge.  Un- 
preventable  contraction  of  the  large  rigid  mass 
of  metal  in  this  inlay  accounts  for  the  gaping 
joint  at  the  gingival  margin  and  angles  ;  bevel 
of  these  margins  «ould  partly,  but  not  com- 
jtletcly,  remedy  this  defect  (26). 


I  Comparing  Fig.  494  with  Fig.  498,  the  cavity  of 
large  interior  dimensions  is  seen  to  yield  «'orse 
results  in  all  ways,  though  metal,  pressure,  and 
hardness  of  mould  were  the  same  m  each  case. 
Experience  in  making  inlays  for  cavities  of 
various  forms  in  extracted  teeth,  where  the 
results  can  be  seen,  enforces  the  conclusion 
that  any  cavity  preparation  that  increases  the 
thickness  or  mass  of  a  cast  inlay  beyond  its 


Fig.   502. 

needs  for  retention  or  strength,  magnifies  the 
defects  in  fit  due  to  contraction  in  casting  or  to 
slight  errors  in  technique. 

Concave  form  of  the  approximal  portion,  and 


Fig.   50.1. 


rounded  bottom  of  the  step,  are  bad  features 
in  the  cavity  in  Fig.  495.  A  step  should  have 
definite  angles,  as  in  Figs.  496  and  497,  to  in- 
crease retention  by  more  perfect  key  action  of 


429 


cement,  and  to  prevent  any  tendency  of  the 
inlay  to  move  under  stress. 

Fig.  500  shows  a  good  form  of  cavity  prepara- 
tion for  lower  premolars. 

In  restoration  of  the  whole  occlusal  surface 
including  parts  of  lateral  walls,  as  in  Fig.  503,  no 
shoulders  should  be  prepared,  or  butted  joints 
upon  the  enamel ;  the  gold  should  overlap 
prejjared  enamel  so  as  to  close  the  johit  \\ith 
certainty   all    round    the    tooth.     Any    special 


Fig.  504. 

form  necessary  for  retention  may  be  cut  in  the 
cement  that  replaces  the  carious  parts. 

Fig.  509  shows  good  preparation  in  bilateral 
caries,  with  abrasion,  of  an  incisor  ;  Fig.  510, 
abrasion  of  the  canme. 


Fio.  505. 

Fig.  512  is  an  example  of  recurrent  approximal 
caries  usual  at  the  margins  of  small  cavities 
filled  without  extension  to  immune  areas. 

Cavities  that  reach  the  Gingival  Line. — In  caries 
of  a  molar  or  premolar  extending  to  the  gmgival 


line  or  beyond  it,  as  in  Figs.  492,  493,  and  501, 
and  the  medial  surfaces  of  Figs.  496  and  499,  satis- 
factory fitting  of  the  margin  by  an  inlay  in  this 
extreme  position  is  exceedmgly  difficult  by  any 
method.     The  obstructing  gum,  the  restricted 


room  to  work  in,  and  the  smaller  medio-distal 
diameter  of  a  tooth  at  the  neck,  render  attempts 
at  accurate  fitting  uncertam.  AVhere  caries  is 
thus  extensive  the  inilio  is  usually  involved  and 
much  dentine  destroyed,  so  that  the  interests 


Fig.    507. 

of  the  tooth,  except  as  regards  its  extreme 
gingival  portion,  are  best  served  by  a  gold 
inlay  (17).  In  such  a  case  comjjletely  remove 
carious  tissue  and  secure  retentive  form  in  the 
gingival  half  of  the  cavity.  Fill  this  part  Avith 
a  good  quick-setting  amalgam  to  a  point 
slightly  crownward  of  the  gum  margin,  and 
finish  before  it  hardens  ;  accurate  gingival  finish 
is  easy  ^^•ith  no  contour  in  the  way.  Fill  the 
rest  of  the  cavity  with  a  soft  cement,  and  when 
it  has  set  prepare  it  in  the  mamier  previously 


430 


explained,  as  in  Figs.  497,  498,  and  500.  Treat 
the  amalgam  as  part  of  the  tooth  to  be  prepared  ; 
it  forms  a  margin  where  accurate  fit  and  finish 
are  easy  to  obtain.     Entire  concealment  of  the 


By  Price's  method  tlie  wax  model  is  prepared  out 
of  the  mouth  in  a  stone  model  of  the  tooth,  which 
serves  also  as  the  mould  in  which  the  inlay  is  cast. 


amalgam  is  not  necessary,  except  on  the  medial 
aspect  of  certain  upper  premolars  or  first  molars, 
where  it  should  not  be  visible  on  the  buccal  side. 
The  thin  edge  of  gold  burnished  to  the  prepared 


FiQ.  509. 

amalgam  makes  an  excellent  jouit,  and  all  the 
interests  of  the  tooth  are  well  served. 

OBTAINING  THE  WAX  MODEL 

Two  methods  are  in  use  for  preparation  of  the 
wax  model.  By  Taggart's  method  the  model  for 
reproduction  in  gold  is  prepared  in  the  mouth. 


Fig.  510. 


Taggart's  Method. — The  cavity  is  prepared 
in  much  the  same  way  as  for  foil,  but  is  made 
more  shallow  on  the  apjiroxiinal  as]iect  with  more 


Fig.  511. 


widely  bevelled  margins,  and  without  undercuts. 
Such  cavity  forms  as  are  seen  in  Figs.  492,  493, 
494,  502,  and  504,  are  suited  to  this  method  ;  the 


431 


margins  in  Fig.  494  should,  however,  be  bevelled, 
and  tlie  cavity  in  Fig.  493  filled  at  the  gingival 
wall  with  amalgam.  Inlay  \\a.\  is  prepared  in 
the  form  of  a  cone,  warmed  until  very  soft  at  the 
point,  and  pressed  into  the  cavity,  which  should 
be  wet  to  prevent  adliesion  ;  after  being  cooled  in 
the  tooth  with  water,  the  wax  is  withdrawn  for 
examination.  If  a  complete  and  unmutilated 
impression  of  the  cavity  is  found,  the  larger 
excesses  of  wax  are  carved  away,  and  the  model 
is  returned  to  the  cavity  (27).  If  the  cavity  is 
approximo-occlusal,  thin  tape  or  celluloid  matri.x 
is  placed  between  the  wax  and  the  adjacent 
tooth  to  support  and  form  the  approximal  portion 
of  the  model.  The  occlusal  wax  is  warmed,  as 
by  a  blast  of  hot  air,  and  the  patient  directed 
to  "  chew  "  it ;  this  operation  indicates  proper 
occlusal  contour  (32).  Without  removing  the 
model    any    excess    is    now    carved    from    the 


Fi. 


r,\-2. 


occlusal  surface,  the  tape  or  matrix  is  removed, 
and  the  approximal  contour  fashioned  by  carvmg 
with  delicate  instruments  ;  the  opposing  teeth 
serve  to  prevent  movement  of  the  model  wliile 
carving  those  parts  accessible  with  the  jaws 
closed.  The  direction  of  the  cutting  should 
be  such  as  not  to  move  the  model  wliile  con- 
touring the  lingual  aspect.  The  approximal 
surface  is  finished  by  rubbing  with  tape  or  a 
warm  burnisher,  and  the  occlusal  surface  by 
smoothmg  with  a  little  ball  of  cotton-wool, 
held  in  conveying  forceps.  If  the  contour  or 
contact  point  is  found  cleficient,  as  is  likely  to 
be  the  case,  the  model  is  removed  and  dried, 
and  with  a  little  wax  on  the  point  of  a  hot 
spatula  the  contact  or  other  point  improved  ; 
the  model  is  then  returned  to  the  cavity  to 
prove  the  correctness  of  all  parts. 

The  sprue  wire  is  now  inserted  at  some  point 
convenient  for  finishing,  preferably  the  contact 
point,  and  in  such  direction  as  will  place  the 


cavity  side  of  the  model  upward  for  investment. 
Unless  the  model  Ls  kept  cool  it  should  be  in- 
vested immediately  upon  removal  from  the 
tooth.  If  allowed  to  stand  for  hours  at  room 
temperature,  67°  F.,  or  warmer  as  in  summer, 
the  elasticity  of  the  wax  will  assert  itself  in 
distortion  of  the  model.  A  temperature 
to  prevent  distortion  causes  contraction  of 
I'l  to  2-3  per  cent  in  the  linear  dimensions  of 
the  model,  according  to  tlie  wax  used.  Thus 
either  contraction  or  distortion  (or  both  of 
these  errors)  is  carried  forward  to  the  mould. 
But  expansion  to  or  beyond  cavity  dimensions, 
with  distortion,  may  be  induced  by  warmth 
at  tlie  time  of  investment.  As  distortion  is 
likely  to  prove  a  more  serious  error  than  con- 
traction, tliLS  latter  plan  is  to  be  avoided. 

Investment. — As  the  compounds  for  sale  are 
not  alike,  only  general  directions  for  manipula- 
tion can  be  given  (19).  Just  sufficient  water 
to  make  tlie  mixture  How  when  jolted  should 
be  used,  and  in  all  cases  a  small  quantity  of  the 
mixture  should  be  first  applied  to  the  model 
with  a  brush,  so  as  to  exclude  air  bubbles.  The 
flask  is  then  filled,  and  jolted  to  ensure  complete 
filling. 

A  good  investment  may  be  made  of  three 
parts  sand  to  one  fine  plaster,  by  measure.  The 
sand  should  be  free  from  other  earths,  organic 
matter,  or  particles  of  mica;  one-third  should 
be  quicksand,  and  the  remamder  of  varying 
fineness  up  to  the  size  that  will  pass  through 
a  mUk-.strainer  screen.  For  investment  the 
model  should  always  be  placed  cavity  side 
upwards,  and  after  a  small  quantity  has  been 
applied  with  a  brush,  the  remainder  is  poured 
directly  on  the  model.  Jolting  causes  the  finer 
sand  to  sink,  while  air,  coarser  grahis,  excess 
of  water  and  plaster,  tend  to  rise  ;  this  makes 
the  walls  of  the  mould  more  firm  and  solid,  and 
the  cavity  side  of  the  mould  especially  so. 
Such  a  mould  will  bear  more  pressure  without 
yielding  than  w  ill  those  made  of  finer  powders, 
such  as  sile.x. 

But  a  mould  made  entirely  of  any  such 
investment  is,  as  elsewhere  mentioned,  from 
I'l  to  2' 3  per  cent  less  in  linear  dimensions  than 
the  cavity,  by  reason  of  contraction  of  the  w^ax. 
The  strength  of  its  walls,  especially  when  heated 
to  induce  maximum  expansion,  is  quite  in- 
sufficient to  control  the  contraction  of  cooling 
gold,  or  to  bear,  without  yieldmg,  more  than  the 
pressure  necessary  to  compensate  for  that  part 
of  contraction  due  to  change  of  gold  from  the 
liquid  to  the  solid  .state.  If  the  walls  of  such  a 
mould  yield,  they  do  .so  ui  an  irregular  way  or 
yield  in  spots.  The  result  is  distortion  or 
irregular  enlargement  of  the  casting,  which,  if 
it  occurs  on  the  cavity  side  of  the  inlay,  renders 
it  useless. 

Price's    Method.  —  Any    approved     form    of 


432 


cavity  may  Le  used,  including  such  forms  as  in  I 
Figs.  496  to  511,  in  many  of  which  the  Taggart 
method  would  be  too  difficult  for  use.  An 
accurate  impression  of  the  cavity  and  adjacent 
parts  of  the  tooth  is  taken  with  a  special  im- 
pression wax  held  in  a  small  metal  tray  suited 
to  the  situation  of  the  cavity,  size  of  tooth,  etc. 
A  tray  for  ajJi^roximo-occlusal  cavities  should 
have  a  septum  or  partition  extending  between 
the  teeth  to  the  gingival  margin  to  support  and 
convey  the  wax  to  the  remotest  parts  of  the 
cavity  and  protect  it  upon  withdrawal.  If  no 
septum  were  used  the  wax  would  fill  the  inter- 
proximal space  like  a  wedge  with  its  thick  end 
towards  the  gum,  and  withdrawal  without 
breakage  or  distortion  would  be  impossible  (31). 
The  impression  is  filled  with  artificial  stone, 
which  forms  a  hard  and  accurate  model  of  the 
tooth. 

In  the  cavity  of  the  stone  model  so  made 
the  fiUing  is  built  in  wax ;  with  a  hot  spatula 
wax  may  be  modelled  to  any  ideal  of  form. 
Guides  for  contour  and  occlusion  are  obtained 
with  the  impression.  No  obstruction,  sali\a,  or 
vital  conditions  are  in  the  way,  as  the  work  is 
done  out  of  the  mouth.  The  stone  tooth  with  the 
finished  wax  filling  in  it  is  invested,  preferably 
in  sand  and  plaster,  the  stone  cavity,  after  the 
wax  is  displaced,  forming  the  more  important 
walls  of  the  mould.  The  metal  is  thus  east 
directly  into  the  stone,  in  which  it  is  afterwards 
conveniently  held  for  finishing.  When  the 
inlay  is  suitably  finished  for  setting,  the  stone 
is  removed  by  fiucturing  with  nippers  in  such 
direction  as  not  to  strain  or  mutilate  the  gold. 
The  iidays  illustrated  were  all  cast  by  this 
method. 

Prices  Artificial  Stone. — This  product  is 
kept  on  hand  in  the  form  of  a  liquid  and  a 
powder,  as  cements  are.  For  use  these  are 
mixed  with  a  spatula  on  a  glass  slab  to  the 
consistency  of  soft  butter,  and  packed  carefully 
into  the  impression  with  a  little  spatula,  so  as 
not  to  mclude  air  bubbles.  It  is  well  to  apply 
first  with  a  fine  sable  pencil  a  little  of  the  stone 
mixed  thin,  so  as  to  ensure  complete  reproduc- 
tion of  detail,  and  then  fill  with  the  thicker 
mixture  ;  the  latter  must  be  thick  enough  not  to 
sag  by  its  own  weight  (20).  When  filled  to 
excess  the  impression  is  turned  stone  side  down 
upon  a  piece  of  brass  plate.  It  may  be  laid  by 
to  set,  or  heated  at  once.  A  low  degree  of  heat 
applied  to  the  stone  hastens  setting,  after  which 
by  means  of  a  gradually  rising  temperature 
the  wax  is  melted  and  burnt  off,  and  the  stone 
is  heated  to  a  low  red  to  harden  it.  Heat 
should  first  be  applied  directly  to  the  stone  to 
set  it,  so  that  its  form  will  not  change  when  the 
impression  melts  (21).  When  properly  mani- 
pulated the  stone  neither  expands  nor  contracts 
on  setting,  and  a  model  thus  made  is  a  very 


accurate,  smooth,  hard  reproduction  of  the 
tooth,  showing  every  detail  of  the  cavity  and 
adjacent  jjarts.  Such  a  model  will  bear  without 
injury  the  full  heat  of  a  gas-and-air  blowpipe, 
and  is  hard  enough  to  bear  without  yielding  any 
pressure  possible  in  casting,  or  even  to  restrain 
or  withstand  the  contraction  of  gold  in  such 
inlays  as  in  Figs.  496,  497,  498,  and  499,  and 
others  of  such  a  form  as  to  allow  this  restraint. 
The  advantages  of  Price's  method  are — 

(1)  It  lessens  the   work  to   be  done   in  the 

mouth. 

(2)  It  simplifies  cavity  preparation  and  the 

management  of  inlay  margins,  with 
marked  economy  of  tooth  tissue. 

(3)  Shrinkage  of  impression  wax  is  less,  and 

is  controlled  by  the  tooth  and  the  tray, 
w  liich  tend  to  maintain  the  dimensions 
of  the  impression  until  it  is  cold. 

(4)  The  inlay  is  modelled  with  greater  ease 

and  accuracy  to  ideal  form. 

(5)  The   mould   may   be  safely  heated  to   a 

greater  degree  of  expansion  than 
common  investment  moulds  permit. 

(6)  Any  pressure  necessary  may  be  used  in 

ca.sting. 

(7)  Contraction    is    restramed    in    important 

parts  of  the  inlay. 

(8)  The    stone    model    affords    a    convenient 

hold  and  a  protecting  support  to  the 
inlay  while  finishing  (22). 

METHODS    OF    CASTING   UNDER    PRESSURE 

The  means  now  in  use  for  application  of 
pressure  to  molten  gold  are  as  follows — 

(1)  Compressed  gas  or  air  applied  under  a 
tight-fitting  lid,  which  is  closed  at  the  moment 
over  the  molten  metal  with  the  mould  in  ver- 
tical position,  its  sprue  serving  as  a  crucible 
(27),  (28). 

(2)  Same  as  No.  1  except  that  freshly 
generated  steam  from  a  wet  asbestos  pad  in 
the  lid  takes  the  place  of  compressed  gas  (24), 
(25). 

(3)  Direct  pressure  of  moulding  clay  in  lid- 
arrangement  of  mould  and  crucible  the  same  as 
Nos.  1  and  2. 

(4)  Suction. — Air  is  exhausted  from  a  receiver, 
which  has  air-tight  jjipe  connection  with  the 
bottom  of  the  flask,  of  which  the  top  is  the 
crucible,  as  in  No.  1.  When  the  metal  is  molten, 
a  stopcock  between  receiver  and  flask  is  opened, 
and  atmospheric  pressure  forces  the  metal  into 
the  mould. 

(5)  Centrifugal  pressure. — At  the  end  of  a 
bar  adjusted  to  describe  a  circle  horizontally  a 
device  holding  both  flask  and  crucible  is  pivoted. 
The  flask  lies  in  a  horizontal  position,  with  the 
fumiel  of  the  mould  ready  to  receive  the  molten 


433 


metal  tliro\^-n  from  the  crucit)le.  The  metal 
is  fused  in  the  crucible  by  l)lo\\pipe  wliile  the 
machine  is  at  rest.  When  fusion  is  complete 
the  machine  is  set  in  motion ;  the  metal  is 
thrown  by  this  motion  into  the  mould,  the 
surplus  metal  in  the  sprue  exerting  pressure  upon 
that  in  the  mould  until  solidification  occurs. 

The  centrifugal  method  has  advantages  over 
the  others.  The  horizontal  position  provides 
against  falling  of  dust,  borax,  or  other  foreign 
matter,  into  the  mould,  the  crucible  being 
separate  from  it.  The  mould  may  be  heated 
to  any  desired  degree  to  receive  the  metal. 
The  pressure  exerted  depends  upon  the  number 
of  revolutions  per  second,  the  diameter  of  the 
circle  traversed,  and  the  weight  of  gold  in  the 
sprue.  These  factors  are  readily  controlled 
by  the  operator  and  are  certain  in  result ;  hence 
any  desired  pressure  can  be  provided  and 
effectively  sustained,  which  is  not  the  case  in 
any  other  device  mentioned  (19).  Sustained 
pressure  is  necessary  because  in  the  earlier 
stages  of  solidification  and  contraction  the  gold 
can  still  be  moved  l)y  pressure,  which  forces 
additional  gold  into  the  mould  from  the  gate 
to  compensate  for  contraction.  Half  an  ounce 
of  gold  revolving  in  a  circle  of  ten  inches 
diameter  at  the  rate  of  five  revolutions  per 
second  gives  an  effective  pressure  upon  the 
casting  of  approximately  half  a  pound  ;  at  ten 
revolutions  two  pounds,  at  twenty  revolutions 
eight  pounds — less  the  pressure  received  by 
the  tapered  walls  of  the  funnel,  which  in  practice 
is  but  a  small  fraction  of  the  total  (19). 

Ordinary  silex  and  plaster  moulds  do  not 
■withstand  such  pressures  as  these.  Their  ^\■l^]\s 
yield  easily,  distorting  the  cast  so  that  it  will 
not  fit ;  so  soft  a  material  can  exert  little  or  no 
restraint  upon  contraction  in  any  direction.  A 
mould  should  withstand  a  low  red  heat  and  a 
pressure  upon  the  casting  of  more  than  two 
pounds,  to  reduce  sufficiently  the  errors  due  to 
contraction  of  gold.  To  make  such  a  mould, 
paint  the  wax  filling,  and  the  stone  model  about 
its  margins,  with  porcelain  body  and  water 
(the  cheap  body  used  in  making  insulators  for 
electric  wiring),  and  invest  in  sand  and  plaster. 
The  porcelain,  though  not  fused,  protects  the 
mould  in  case  of  decomposition  of  plaster  by 
heat.  The  investment  should  contain  the 
minimum  quantity  of  plaster  that  will  hold 
the  sand  together. 

RETENTION    OF    INLAYS 

Force  is  seldom  exerted  upon  an  inlay  in 
a  direction  opposite  to  that  of  occlusion,  and 
this  is  the  only  direction  in  which  it  should 
be  possible  to  withdraw  an  inlay  that  is  ex- 
posed   to    stress.       Against     such    withdrawal 


cement  when  set  serves  as  a  key  rather  than 
an  adhesive ;  in  the  latter  property  cement  is 
uncertain,  and  in  cavities  of  saucer  form  cannot 
be  depended  on  to  hold  an  inlay,  even  w  here  it  is 
not  exposed  to  stress.  The  retentive  form  of  a 
cavity  is  that  form  which  allows  cement  to  act 
as  a  key  bet^\•een  the  gold  and  the  cavity  walls ; 
retentive  forms,  as  seen  in  the  figures,  are  used 
according  to  the  needs  or  opportunities  found  in 
each  ca.se.  For  want  of  recognized  names  for 
parts  of  inlays  and  inlay  cavities  these  are  not 
now  conveniently  described.  However,  the 
short  dowel,  or  projection  of  metal  fitting  the 
hole  prepared  for  it  in  the  incisal  or  occlusal 
part,  and  the  rib  or  tongue  fitting  the  longi- 
tudinal groove  in  the  approximal  surface,  together 
serve  as  means  of  retention  in  Figs.  498,  500, 
501,  505  and  507.  A  dowel  fitting  the  pulp- 
cavity  and  root-canal  is  the  chief  means  of 
retention  in  Figs.  506,  508,  and  511,  which  are 
pulpless  teeth.  The  means  of  retention  in  the 
other  cases  illustrated  will  be  obvious  to  the 
reader. 

Additional  retention  can  be  provided  by 
removal  of  wax  from  suitable  points  on  the 
cavity  side  of  the  model,  to  form  depressions  in 
the  gold  for  projections  of  cement.  The  same 
effect  may  be  secured  in  such  an  inlay  as  Fig.  500 
by  a  cut  made  with  a  carborundum  disc  across 
the  aijproximal  portion  after  casting.  Wliere 
room  in  the  cavity  allows,  as  in  Fig.  505,  spurs 
may  be  raised  upon  the  gold  with  a  sliarji  tool. 

INSERTION    AND    CEMENTATION 

Complete  or  close  finish  of  inlay  margins 
should  not  be  undertaken  Ijefore  setting.  The 
removal  of  small  excesses  of  metal  overlapping 
unprepared  enamel  is  more  safely  and  evenly 
accomplished  when  tlie  inlay  is  in  the  tooth. 
Such  unfinished  overlap  as  that  seen  in  Fig.  504 
should  remain  until  the  inlay  is  set  and  well 
burnished  at  the  margins. 

Before  preparing  to  cement  an  inlay  try  its 
fit  in  the  cavity.  If  it  will  not  go  into  place 
the  cause  may  be  :  foreign  matter  in  the 
cavity ;  beads  from  air  bubbles,  or  other  faults 
in  the  mould ;  distortion  from  yielding  walls  of 
mould  ;  uncontrolled  contraction  of  wax  model, 
investment,  or  metal ;  or  all  of  the.se.  Misfit 
due  to  the  two  latter  causes  is  w  ithout  remedy 
except  by  making  another  inlay.  There  is, 
however,  a  remedy  for  a  certain  error  in  fit  due 
to  contraction,  which,  while  allowing  the  inlay  to 
go  into  place  at  the  occlusal  surface,  as  in  Figs. 
492,  493,  and  494,  leaves  the  gingival  joint  open. 
In  this  case,  having  found  the  inlay  go  into 
place  at  the  occlusal  surface,  remove  and  dry 
it.  Heat  the  inlay  and  while  hot  apply  to  its 
gingival  end  a  small  piece  of  base-plate  gutta- 
percha.    Pteturn    before    cooling    to    the    wet 


434 


cavity  and  press  quickly  into  place.  Cool  and 
remove.  Cut  surplus  gutta-percha  away  with 
sharp  knife  and  set  with  cement,  as  if  the  inlay 
were  all  gold.  Gutta-percha  ^^ill  not  dissolve 
in  the  mouth. 

The  rubber-dam  is  not  necessary  in  gold  inlay 
work.  During  preparation  the  cavity  should 
be  wet,  and  for  the  use  of  wax  it  must  be  so. 
Rolls  of  cotton-wool  and  paper,  and  the  saliva- 
pump,  can  ah\-ays  be  used  with  success  to 
maintain  dryness  -whOe  setting. 

Before  an  inlay  is  cemented,  all  filling-material , 
cement,  or  decalcified  tissue,  should  be  removed. 
A  single  body  of  fresh  cement  should  occupy  all 
the  space  between  the  gold  and  the  cavity  walls. 
A  slo\\'  setting  cement  is  to  be  preferred.  For 
teeth  exposed  to  view  its  colour  should  be  white 
or  pale  yellow.  The  liquid  and  the  powder 
should  be  used  in  the  proportion  knoAMito  make, 
\\'hen  set,  a  strong  hard  mass  having  the  mmimuin 
liability  to  solution  in  the  mouth.  The  inner 
surface  of  the  inlay  and  all  the  walls  of  the  cavity 
should  be  covered  \vith  cement ;  no  air  spaces 
should  be  allowed.  The  inlay  is  then  forced 
into  place,  and  held  securely  against  movement 
by  the  opposing  teeth  or  otherM-ise  until  the 
margins  are  burnished  into  contact  ^nili  the 
prepared  enamel  at  all  points.  Burnishing 
should  be  done  before  setting  of  cement  occurs, 
as  otherwise  the  joint  \\'ill  be  imperfectly  closed. 

When  the  cement  has  set,  polish  away  excess 
of  margins,  scars  of  burnishing,  etc.,  Avith  fine 
paper  discs,  not  stone  points  or  wheels.  Wliere 
exjaosed  to  view,  inlays  may  be  given  a  dull  finish 
by  rubbing  the  gold  with  wet  powdered  pumice 
on  the  end  of  the  finger  as  a  final  application. 

W.  C.  G. 
BIBLIOGRAPHY 

(1)  Alter,  H.      Partial  Restoration  of  Incisors  by  Cast 

Gold  Inlavs   combined  with   Porcelain.     Dental 
Cosmos,  1909,  Vol.  LI,  p.   1227. 

(2)  Black,  G.  V.     Porcelain  and  Gold  Inlays.    Opera- 

tive. Dentistry,  Vol.  II,  p.  330. 

(3)  CoNZETT,  J.  V.     The  Gold  Inlay.     Dental  Costnos , 

1910,  Vol.  LI  I,  p.  1339.     Disnission.  p.  1367. 

(4)  Cpster,    L.    E.     Approximal    Contact   for   Gold 

Inlays.     Dental  Cosmos,  1908,  Vol.  L,  p.   1451. 

(5)  DiTTMAE,     G.     W.     Cast     Gold     Inlay.     Dental 

Review,  1908,   pp.   172,  649. 

(6)  DiTTMAB,  G.  W.     Remarks  on  Cast  Gold  Inlay. 

Dental  Revieu;  1909,  p.  339. 

(7)  GiLLETT,     H.     W.     Discussion    of    Gold    Inlays. 

Dental  Cosmos,  1910,  Vol.  LII,  p.   1288. 
(S)   GosLEE,    H.    .J.     Gold    Inlays.     Dominion   Dent. 
Jour.,  1909,  pp.  491,  541. 


(9)  GosLEE,    H.    J.     Gold    Inlays.     Dental    Review, 
1908,  p.  684. 

(10)  HoFHiNG,    R.    H.     Discvission    of    Gold    Inlays. 

Dental  Cosmos,  1910,  Vol.  LII.  p.  1291. 

(11)  Johnson,    C.    N.     Gold   Inlays.     Principles   and 

Practice,  3rd  ed.,  p.  255. 

(12)  Johnson,  C.  N.     Selection  of  Fillings.     Dominion 

Dent.  Jour.,  1910,  p.  438. 

(13)  Knowles,   S.   J.     Gold  Inlays  (Matrix  Method). 

Dental  Review,  1907,  p.  257. 

(14)  Moore,   W.    D.     Gold   Inlays   (Matrix   Method). 

Dental  Review,  1907,  p.  265. 

(15)  Newkirk,     G-iRRETT.     Comments     on     Use     of 

Inlays.     Dental    Review,   1910,  pp.    1269  et  seq. 

(16)  Nyman,    J.    E.     Construction    of    Gold    Inlays. 

Johnson's  Operative  Dentistry,  p.  301.  Sso  new 
ed. 

(17)  Perry,  S.  G.     Sectional  Inlays.     Dental  Cosmos, 

1910,  Vol.  LII.  p.  1204. 

(18)  Plat^chik    B.     Fused   Gold    Inlay.      Brit.  Dent. 

Jotir.,  1907,  Vol.  XXVIII,  p.  970. 

(19)  Price,   Weston  A.      Laws  determining  Casting 

and  Fusing  Results  .  .  .  Control  .  .  .  New  and 
Rational  Technique.  Items  of  Interest,  1908, 
May,  p.  363,  and  June,  p.  409. 

(20)  Price,     Weston     A.     Detailed     Technique     for 

making  Dental  Restorations  on  Artificial  Stone 
Models.     Dominion  Dent.  Jour.,  1908,  p.  394. 

(21)  Price,    Weston    A.     Casting     to    Models;     its 

Advantages  and  Technique.  Items  of  Interest, 
Sept.,  1910,  p.  681. 

(22)  Price,    Weston   A.     Advantages    of    the    Stone 

Model.     Dental  Cosmos,  1910,  Vol.  LII,  p.  1015. 

(23)  Price,  Weston  A.      The  Laws  determining  the 

Behaviour  of  Gold  in  Fusing  and  Casting. 
Dental  Cosmos,  March  1911,  Vol.  LIII,  pp.  165 
et  seq. 

(24)  Solbrig,   O.     Cast  Gold  Inlays.      V Odontologie, 

1908,  Jan.  15,  p.  11. 

(25)  SoLBRiG,   O.     Casting   Gold   Inlays.     Dental  Re- 

view, 1908,  p.  112. 

(26)  Spring,     W.     A.     Fillings     v.     Inlays.     Dental 

Review,  1909.  pp.  1032,  1101. 

(27)  Tagoart,  W.  H.     An  Accurate  Method  of  making 

Gold  Inlays.  Dental  Cosmos.  1907,  Vol.  XLIX, 
p.   1117. 

(28)  Tagoart,  W.  H.     Gold  Inlay.     Items  of  Interest, 

April  1908,  p.  267. 

(29)  Taggart,  W.  H.     Remarks.     Dental  Review,  190S, 

pp.  173,  615,  1049. 

(30)  Tenney,  L.  S.     Remarks  on  Gold  Inlay  Casting, 

etc.     Dental  Review,  1908,  pp.  660,  794,  1047. 

(31)  Thompson,  C.  N.     Cavities  for  Inlays.     Dominion 

Dent.  Jour.,  1907,  p.  361. 

(32)  Thompson,  C.  N.     Experience  with  Cast  Metal. 

Dental  Review,  1910,  pp.  1214,  1251. 

(33)  Van    Horn,    C.    S.     Cast    Gold    Inlays.     Dental 

Cosmos,  1909,  Vol.  LI.  p.  546. 

(34)  Van    Horn,    C.     S.      Review    and    Conmientary 

on  Casting  Size  of  Wax,  Dental  Cosmos,  1910, 
Vol.  Lll.  p.  873. 

(35)  Webster,  A.  E.     Gold  Inlay  in  Artificial  Stone. 

Dominion  Dent.  Jour.,  1908,  p.  461. 

(36)  Webster,    A.    E.     Casting    Process    for   Fillings. 

Dominion  Dent.  Jour.,  1909,  p.  363. 


CHAPTER  XXVI 

DIAGNOSIS   OF   THE   CAUSE   OF   PAIN 


That  it  is  of  primary  importance  to  the  witli  the  obvious  signs  and  symptoms,  will  at 
dentist  to  be  able  to  form  a  correct  conckision  once  afford  a  clue  to  the  elucidation  of  the  case ; 
as   to   the  cause   of   the   pain   from   which   his   ,    but    there    are    other    cases,    often    the    most 


Skort    root 


To  papiU te  and 
muc.  membrane 
of  tonyue 

CubtinffuaC 
gland. 


ToTENSOR    VELJ 
PALATINI 


7&  ck  in 

and      . 
lourer  ttp 

Tb  MYLOHY0IDEU6 
To  anterior    belly 
of   DIGASTRIC 


Fia.  513. — Plan  of  the  trigeminal  norve  showing  the  relations  of  tlie  inferior  alveolar  nerve. 

(After  BuRCHARD  and  Flower.) 


patient  is  sufiermg,  is  a  proposition  from  which 
few,  if  any,  will  dissent.  In  the  majority  of 
cases   the   statement   of  the   patient,   together 


interesting,  where  the  problem  is  surrounded 
with  difficulties,  which  tax  the  skill  of  the 
dentist  and  demand  his  best  efforts. 


436 


436 


At  tlie  outset  one  is  confronted  with  two 
conditions  with  regard  to  the  oral  cavity,  which 
are  frequently  confounded,  and  which  it  is 
necessary  to  distinguish  carefully,  namely, 
odontalgia  and  neuralgia. 

As  jjain  means  the  over-excitation  of  sensory 
nerves,  odontalgia  is  that  form  of  pain  which  is 
definitely  referred  by  the  patient  to  a  particular 
tooth  or  teeth,  while  neuralgia  may  be  defined 
as  jiain  referred  to  some  point  other  than  its 
origin ;  e.  g.  pain  referred  to  the  distribution  of 
a  sensory  nerve  may  be  due  to  over-excitation 
of  any  portion  of  the  nerve  m  its  terminal 
distribution,  to  diseases  affecting  any  portion 
of  the  nerve-trunk,  or  to  disorders  affecting  its 
origin ;  or  irritation  of  one  sensory  nerve  may 
be  referred  to  another  sensory  nerve  (10). 
While  these  two  conditions,  odontalgia  and 
neuralgia,  may  thus  be  clearly  defined,  it  must 
be  remembered  that  it  is  frequently  difficult  to 
distinguish  between  them  ;  odontalgia,  which  is 
frequently  intermittent,  being  often  associated 
«ith  neuralgia  and  frequently  assummg  a  neur- 
algic character. 

Conditions  which  may  give  rise  to  Odontalgia 

T.— Injuries  and  diseases  of  the  pulp. 

1.  Exposure  by  fracture  of  the  tooth. 

2.  Varying  degrees  of  inflammation  caused 

by  attrition,  erosion,  or  caries,  leadmg 
to— 

(a)  Exposure  of  the  pulp  by  disease. 

(b)  Calcific  and  other  degenerations. 

(c)  Suppuration  without  exposure. 

II. — Injuries  and  disease  of  the  periodontal 
membrane. 

1.  Periodontitis  due  to  direct  injury. 

2.  Periodontitis    due    to    septic    extension 

from  pulp — apical  abscess. 

3.  Alveolar  abscess — necrosis  of  the  root. 

4.  Periodontitis  resulting  in  hyperplasia  of 

the  cementum,  or   its   absorption,  or 
both  conditions  combined. 

5.  Pam  from  exposure  of  the  cementum. 

III. — Ulcerations  in  the  mouth. 

I^^. — Periosteal  inflammations  of  the  jaw. 

Conditions  which  may  give  rise  to  Neuralgia 

All  those  enumerated  under  the  heading  of 
Odontalgia,  and  in  addition — 

I. — General  systemic  conditions,  e.  g.  gout, 
rheumatism,  syphilis,   malaria,   anae- 
mia, influenza,  pregnancy. 
II. — Difficult  eruption   and    malposition    of 

teeth. 
III. — Odontomes. 


IV. — In  edentulous  persons  compression  of 
nerve  filaments  of  alveolar  border  by 
osseous  deposit. 
V. — Inflammation  in  the  maxillary  sinus  ; 
effect  of  coryza  on  maxillary  division 
of  trigeminal  nerve. 

VI. — Intra-cranial  afi^ections  of  nerves.  Neur- 
algia quinti  major,  epileptiform  neur- 
algia. 

ODONTALGIA  AND  NEURALGIA 

Exposure  of  the  Pulp  due  to  Fracture  of  the 
Tooth. — In  the  majority  of  eases  there  is  the 
history  of  injury,  the  very  evident  fracture,  and 
the  sensitive  exposed  pulp.  As  the  incisors  and 
canines  are  more  exposed  to  injury  they  offer 
the  most  frequent  examples  of  this  accident, 
but  the  possibility  of  the  molars  and  premolars 
suffering  from  a  like  injury,  the  result  of  chewing 
some  hard  substance,  or  of  a  blow  or  fall  where 
the  upper  and  lower  teeth  are  forcibly  impacted, 
nuist  not  be  overlooked.  Tomes  mentions  the 
case  of  a  medical  man  who,  happening  to  lean 
forwaid  in  his  carriage  at  the  moment  when  it 
was  suddenly  pulled  up,  \\as  pitched  upon  his 
head  and  stunned ;  for  upwards  of  a  year  he 
suffered  from  occasional  neuralgic  pains,  which 
were  ultimately  found  to  be  due  to  a  sound 
upper  molar  that  had  been  split  right  through, 
the  palatuie  bemg  separated  from  the  buccal 
roots.  The  pulp  had  remained  alive,  and  the 
fracture  was  long  overlooked,  it  having  followed 
the  natural  fissures  of  the  crown,  and  no  dis- 
placement having  taken  place. 

When  fracture  occurs  there  is  always  a  certain 
amount  of  periodontitis,  which  may  be  present 
even  before  the  pulp  has  become  septic  through 
exposure  and  the  periodontal  membrane  has 
become  affected  m  consequence.  Salter  is  of 
opinion  that  when  fracture  of  the  root  occurs 
the  puli^-cavity  is  always  opened ;  but  at  the 
same  time  the  pulp  is  not  exposed  to  external 
uifluences  unless  the  alveolus  is  also  broken  and 
the  gum  lacerated.  Circumstances  are  present, 
therefore,  favourable  for  union  of  the  fracture, 
of  which  there  are  several  cases  on  record ; 
always  provided  that  the  vitality  of  the  pulp 
is  unimpaired.  Under  these  circumstances  a 
certain  amount  of  neuralgia  is  to  be  expected. 

Varying  Degrees  of  Inflammation  caused  by 
Attrition,  Erosion,  or  Caries,  etc. — The  effects  of 
a  moderate  amount  of  irritation  of  a  dental  pulp 
have  been  specially  noticed  by  Salter  and  Black, 
and  it  is  not  difficult  to  understand  that  where 
a  pulp  is  sufficiently  stimulated  to  produce  slight 
pathological  changes,  such  as  hyperaemia  and 
secondary  dentine,  it  may  at  the  same  time  give 
rise  to  odontalgia,  possibly  of  a  neuralgic  type. 
The  cause  of  such  pain  is  not  always  very 
apparent,  and  often  can  only  be  arrived  at  by 


437 


careful  testing  and  a  process  of  exclusion.     It  | 
would  also  appear  that  when  the  pain  is  due  to 
more    severe    irritation    of    the    pulp    \\ithout 
exposure,  it  is  local  in  character :    the  tooth  is 
very  sensitive  to  heat  and  cold,  and  is  readily  1 
distinguislied    as    the    exciting    cause    of    the  I 
odontalgia.     It  is  otherwise,  however,  when  the 
puljj  is  exposed,  whether  by  caries  or  accident 
(and  a  pulp  may  be  practically  exposed  whUe 
covered  by  a  layer  of  softened  dentine).     Violent 
pain  may  then  be  caused  by  the  application  of 
heat  or  cold,  but  the  pain  is  frequently  referred 
to   some   other   region,   and   the   tooth   as   the 
exciting  cause  may  be  overlooked :   the  pain  has 
become  neuralgic  (19). 

It  has  often  been  noted  that  caries  in  its  early 
commencement  will  cause  toothache,  although 
when  the  disease  is  further  advanced  there  may 
be  little  or  no  pain,  which,  liowever,  recurs  with 
great  intensity  when  the  pulp  at  last  becomes 
exposed  (19). 

In  attrition,  erosion,  and  caries,  once  the 
dentine  is  exposed  a  slight  but  certain  stimulus 
is  conveyed  to  the  pulp,  which  is  bound  to  set 
up  more  or  less  pathological  action  resulting 
in  tissue  change,  and  from  this  varying  degrees 
of  odontalgia  or  neuralgia  arise.  These  degener- 
ative changes  frequently  result  in  "  dentine  of 
repair  ",  or  the  so-called  pulii-stonc,  or  both  in 
the  same  pulj).  Hopewell-Smith  is  of  opinion 
that  when  pain  results  in  these  cases  it  is 
produced  by  the  mechanical  pressure  of  the 
"  puliJ-stone  "  on  the  nerve-bundles  of  the  pulp. 
He  also  quotes  an  interesting  case  in  which  three 
teeth  were  removed  from  the  same  mouth  for 
excruciating  and  incurable  pain  ;  the  pulps  of 
these  teeth  contained  probably  the  largest 
nodules  on  record. 

"  Irritable  pulp  "  may  be  a  manifestation  of 
any  morbid  condition  that  affects  the  pulp. 
The  term  merely  describes  a  symptom  common 
to  them  all,  which  may  be  produced  by  reflex 
causes  and  systemic  conditions,  as  well  as  by 
pulp  disease. 

In  hyperaemiaof  the  pulp,  which,  it  should  be 
remembered,  occurs  in  the  early  stages  of 
inflammation,  as  well  as  per  se  when  infection 
has  not  occurred,  the  pain  is  sliarp,  is  sudden 
in  onset  as  a  rule,  and  dies  down  gradually. 
If  the  condition  persists  the  pain  becomes  a 
dull  grumbling  ache  with  occasional  inter- 
missions and  exacerbations,  and  is  frequently 
accompanied  by  tenderness  of  the  tooth  to 
pressure,  indicating  either  sympathetic  hyperaes- 
thesia  of  the  periodontal  membrane,  or  extension 
of  the  hyperaemia  to  that  structure.  The  cause 
is  usually  caries,  and  may  be  caries  of  such 
limited  extent  as  to  render  its  discovery  difficult. 
It  is  a  common  cause  of  pain  in  teeth  around 
whicli  recession  of  the  gum  has  occurred, 
altliougli   they   are   otherw  ise   sound  ;    and   its 


occurrence  under  large  metallic  fillings  is  but 
too  frequent.  In  short  any  condition  23roducing 
prolonged  or  great  irritation  of  the  fibrils  or  pulp 
will  produce  it. 

Acute  inflammation  of  the  pulp  produces  pain 
that  is  almost  pathognomonic  when  once  the 
throbbing  character  is  established.  Pain  due 
to  hyperaemia  may  be  throbbing,  but  it  is 
usually  more  or  less  intermittent,  and  Ls  aggra- 
vated by  both  heat  and  cold  ;  while  the  pain  of 
acute  inflammation  is  continuous,  and  after  the 
early  stages  is  usually  somewhat  (and  sometimes 
greatly)  relieved  by  cold,  thougli  still  intensified 
by  heat.  Chronic  hyperaemia  and  inflamma- 
tion, and  the  degenerative  states  of  the  pulp  to 
which  they  give  rise,  are  much  moi'e  frequently 
the  cause  of  referred  pain.  Referred  i)ain  due  to 
morbid  pulp  conditions  may  or  may  not  be  ex- 
perienced in  the  teeth.  In  the  latter  case  it  is  out- 
side the  scope  of  tliis  chapter  ;  but  in  the  former, 
pain  may  be  referred  to  any  tootli  on  the  same 
side  in  either  jaw ;  such  cases  are  within  daily 
experience  of  every  dentist.  The  frequent 
association  of  pain  in  the  premolar  region  with 
lesions  of  the  pulj)  of  the  third  molar  is  inter- 
esting, j^artici'la'l.V  in  the  maxilla,  and  the 
often  exact  correspondence  between  teeth  in 
the  maxilla  and  mandible  in  cases  of  referred 
pain  is  notable  (9). 

In  localized  suppuration  of  the  pulfj  severe 
odontalgia  is  present,  especially  when  confined 
beneath  a  filling ;  the  pain  is  generally  of  a 
throbbing  character,  aggravated  by  thermal 
changes,  and  frequently  associated  with  more 
or  less  periodontal  inflammation.  Intense  local 
pain  is  often  experienced  when  the  pent-up  pus 
is  allowed  to  escape  on  removal  of  the  filling, 
the  alteration  of  the  blood  pressure  in  the  j)ulp 
appearing  to  be  the  cause  of  this  very  severe 
paroxysm.  With  the  evacuation  of  the  pus, 
however,  there  is  generally  complete  relief  from 
the  painful  symptoms.  In  these  cases,  as  well  as 
in  the  antecedent  condition  of  inflammation,  the 
colour  of  the  tooth  is  an  important  indication 
of  the  condition  of  the  puljj ;  it  is  generaUy 
slightly  darker  and  less  translucent  than  a 
perfectly  healthy  tooth  ;  the  periodontal  mem- 
brane, on  percussion  of  the  tootli,  fre(iuently 
gives  a  more  or  less  ]iaiiiful  rcs|Minse. 

Periodontitis  due  to  Direct  Injury. — In  dealing 
with  the  conditions  of  the  periodontal  mem- 
brane, or  root-membrane,  it  must  not  be  for- 
gotten that  it  is  the  touch-organ  of  the  tooth  ; 
consequently,  pain  arising  here  is  more  likely 
to  be  referred  by  the  patient  to  its  correct  source 
than  is  the  case  where  it  arises  in  connection 
with  affections  of  the  pulp ;  in  other  words, 
the  manifestation  of  pain  is  odontalgia  rather 
than  neuralgia. 

Periodontitis  arising  from  traumatic  causes 
may   cliiefly    be   produced    by    blows,    wounds. 


438 


separating  for  dental  operations,  and  the  mov- 
ing of  teeth  in  the  practice  of  orthodontics.  In 
enumeratmg  these  causes  it  must  not  be  for- 
gotten that  any  injury  of  sufficient  severity  to 
cause  an  inflammation  of  the  root-membrane 
may  at  the  same  time  brmg  about  the  death  of 
the  j)ulp  ;  this  is  specially  true  with  regard  to 
blows.  The  general  symptoms  are  soreness  and 
looseness  of  the  tooth,  together  with  varying 
degrees  of  vascular  disturbance  of  the  gum  over- 
lymg  the  tooth.  The  diagnosis  is  in  nearly  all 
cases  sufficiently  obvious — the  root  membrane 
is  bruised. 

Periodontitis  due  to  Septic  Extension  from  the 
Pulp  :  Apical  Abscess. — As  Black's  description 
of  this  affection  so  entirely  corresponds  with  the 
experience  of  many  cases,  it  is  thought  best  to 
quote  largely  from  his  remarks  (8).  This  is 
one  of  the  most  painful  affections  to  which  the 
teeth  are  liable.  It  consists  in  an  inflammation 
of  the  root-membrane  always  beginning  in  the 
apical  space,  in  the  immediate  neighbourhood 
of  the  apical  foramen.  It  never  occurs  during 
the  life  of  the  pulp  of  the  tooth,  or,  if  so,  not 
until  the  pulp  is  irreparably  inflamed.  The 
tissue  in  this  inflammatory  process  is  encased 
between  the  walls  of  the  alveolus  and  the  root 
of  the  tooth  in  such  a  way  as  tc  hinder  its 
expansion  when  engorged  by  the  influx  :if  blood. 
The  tissue,  although  in  normal  conditions  not 
unusually  sensitive,  is  richly  supplied  with 
nerves,  and  in  the  inflammatory  state  soon 
becomes  exquisitely  painful ;  this  inflammation 
is  very  prone  to  terminate  in  suppuration,  with 
the  formation  of  alveolar  abscess.  The  affection 
may  precede  the  death  of  the  pulp,  or  at  once 
follow  that  occurrence,  or  may  be  indefinitely 
delayed. 

The  symptoms  vary  much  in  different  cases, 
but  this  variation  is  more  as  to  the  severity  of 
the  pain  than  the  character  of  it.  It  usually 
commences  as  a  dull  pain  referred  to  the  affected 
tooth ;  this  is  at  first  somewhat  relieved  by 
pressure,  but  as  the  inflammation  increases 
in  severity  pre.ssure  of  the  opposing  teeth  causes 
extreme  pain,  and  as  the  swelling  of  the  tissues 
in  the  apical  space  causes  a  slight  elevation  of 
the  tooth  in  its  socket,  thus  bringing  the  whole 
force  of  occlusion  upon  the  one  tooth,  this 
becomes  the  source  of  great  suffering.  The 
mucous  membrane  over  the  affected  root 
presents  signs  of  inflammation  ;  it  becomes  of 
a  deeper  red  than  the  rest,  and  the  pressure  of 
the  finger  causes  pain.  If  the  case  tends  to 
become  one  of  acute  alveolar  abscess,  the  gum 
presents  a  more  purple  hue,  and  the  pain 
becomes  continuous  and  throbbing ;  this  con- 
dition may  be  delayed  for  several  days,  but 
usually  pus  forms  rapidly  in  the  apical  space — • 
within  twenty-four  hours. 

The     diagnosis     of     this     condition     usually 


presents  little  difficulty.  The  pain  caused  by 
pressure  on  the  affected  tooth  is  a  constant 
symptom  that  distinguishes  it  from  inflamma- 
tions of  the  pulp,  except  ui  those  cases  where 
there  is  a  certain  amount  of  j)eriodontitis  associ- 
ated with  inflammation  of  the  pulp,  and  here  the 
I^ronifjt  treatment  of  the  pulp  will  m  most  cases 
relieve  the  sensitiveness  manifested  on  per- 
cussion. In  apical  periodontitis  the  pain  is 
always  referred  definitely  to  a  particular  tooth, 
while  in  pulp  inflammation  the  patient  is  often 
uncertain  as  to  the  exact  location  of  the  pain. 
Another  point  of  importance  is  the  fact  that  the 
dental  pulp — more  especially  when  diseased — is 
markedly  sensitive  to  thermal  changes,  while 
the  periodontal  membrane  is  unaffected  by 
changes  of  temperature.  There  is,  however, 
one  condition  in  which  thermal  changes  convey 
sensations  to  the  root-membrane  :  that  is  where 
the  pulp-chamber  of  the  tooth  is  filled  with  gas 
in  such  a  way  as  to  cause  pressure  on  the  tissues 
of  the  apical  space.  In  this  case  heat  will  give 
rise  to  an  expansion  of  the  gas,  increasing  the 
pressure  and  the  pain,  while  the  application  of 
cold  will  relieve  it.  The  symiitoni  is  diagnostic  ; 
for  in  the  affections  of  the  pulp  both  heat  and 
cold  usually  cause  paui  when  suddenly  applied. 

Alveolar  Abscess. — A  consideration  of  this 
condition  naturally  follows  from  what  has  been 
said  above  concerning  apical  abscess,  as  all 
alveolar  abscesses  result,  with  certain  minor 
exceptions,  from  an  inflammation  having  its 
seat  in  the  apical  space.  The  affection  is,  how- 
ever, described  in  detail  in  Chapter  XLII,  and 
need  not  be  further  considered  here. 

Necrosis  of  a  root  may  occur  in  coimection 
with  a  chronic  purulent  inflammation  of  the 
apical  space.  Beyond  a  local  inflammation  of 
the  gum  and  a  chronic  discharge  of  pus  there 
Ls  little  discomfort  as  compared  with  other 
affections  of  the  teeth. 

Up  to  the  present  the  effect  of  acute  inflam- 
matory conditions  upon  the  root-membrane  has 
been  discussed,  but  here,  as  elsewhere  in  the 
body,  chronic  inflammation  can  also  induce 
important  changes,  which  may  give  rise  to 
painful  sensations. 

Absorption  of  the  roots  of  permanent  teeth 
may  occur- — 

(a)  owing  to  pressure  of  an  erupting  tooth ; 

(b)  in  young  persons  where  the  pulp  is  still 

alive ; 

(c)  in    older   persons    as    a    result    of    senUe 

changes. 

In  the  first  class  are  those  cases  where  the 
developing  canine  impinges  on  the  root  of  the 
lateral  or  the  roots  of  the  premolar,  or  where  a 
misplaced  third  molar  impinges  on  the  roots  of 
the  second  molar.  The  absorption  engendered 
frequently  involves  the  pulp-chamber  of  these 


439 


teeth,  so  that  if  they  are  otherwise  healthy  the 
detection  of  the  source  of  the  pain  becomes  a 
matter  of  difficulty.  It  is  only  by  bearing  the 
possibility  of  such  cases  in  mind,  when  certam 
teeth  have  not  erupted,  and  makuig  a  careful 
examuiation  with  a  fine  probe  beneath  the  gum, 
and  invoking  the  help  of  X-rajs,  that  a  correct 
conclusion  can  be  arrived  at,  \\hen  the  patient 
is  suffering  from  obscure  pulp  mitation. 

In  the  second  class,  where  absorptive  inflam- 
mation takes  jjlace  in  young  persons  \\hile  the 
pulj)  is  stUl  alive,  a  few  cases  have  occurred 
that  seemed  to  pomt  to  some  general  constitu- 
tional condition  being  the  cause,  such  as 
anaemia  ;  \\hUe  the  possibility  of  the  absorption 
being  the  sequela  of  an  attack  of  influenza  must 
not  be  overlooked.  The  signs  that  would  lead 
one  to  suspect  this  condition  are  a  constant 
gnawing  pam,  sometimes  more  severe,  and 
.slight  tenderness  on  percussion  ;  and  modifica- 
tion of  these  sensations  by  heat  and  cold. 
There  is  no  obvious  loosening  of  the  teeth.  In 
fact,  in  the  cases  observed  there  was  apparently 
pulp  irritation ;  but  when  the  pulp  ^^•as  devital- 
ized the  persistence  of  the  discomfort  necessi- 
tated tlie  extraction  of  the  tooth,  when  the 
real  source  of  the  mischief  was  revealed. 

In  older  patients  teeth  are  often  lost  prema- 
turely owing  to  absorjjtion ;  here  there  is  but 
trifling  discomfort,  and  the  looseness  of  the  tooth 
is  the  i^roniinent  sign. 

Hyperplasia  of  the  Cementum  (Dental  Exostosis) 
is  a  result  of  chronic  inflammation  of  the  root- 
membrane,  and  is  frequently  associated  with 
a  Umited  amount  of  absorption.  The  crowns 
of  the  teeth  whose  roots  present  hyperplasic 
changes  may  or  may  not  present  varying  degrees 
of  caries,  and  while  many  of  these  cases  are 
associated  with  ill-defined  pam,  in  most  the 
presence  of  an  excess  of  cementum  is  unsus- 
pected initil  the  tooth  is  extracted.  Under 
these  circumstances  it  is  a  condition  that  is 
very  difficult  to  diagnose  with  any  degree  of 
certainty,  and  the  diagnosis  often  can  only  be 
arrived  at  by  a  process  of  exclusion.  Teeth 
affected  with  this  disease  are  said  to  be  intolerant 
of  percussion  with  an  instrument ;  they  can 
be  moved  to  a  certain  extent  in  their  sockets, 
but  their  mobility  is  suddenly  limited.  X-rays 
may  afford  considerable  help  in  forming  a 
correct  conclusion  about  this  condition,  but 
from  what  has  been  said  above  it  is  extremely 
doubtful  ^^■hether  exostosis  is  a  direct  source  of 
pain. 

Exposure  of  the  Cementum.  —  Wliere  from 
various  causes  in  middle  life  the  gum  recedes 
from  its  close  attachment  to  the  neck  of  a 
tooth,  and  the  junction  of  the  enamel  and 
cementum  is  exposed  even  without  any  evidence 
of  caries,  considerable  pain  may  be  experienced. 
Tliui  may  be  produced  by  light  touches  of  the 


finger-nail,  tooth-brush,  or  an  instrument,  as 
well  as  by  thermal  changes.  It  would  appear, 
from  its  yielding  to  treatment  by  caustics,  to 
be  due  to  the  exposure  of  the  cementum ;  the 
large  percentage  of  organic  material  ui  this 
tissue,  as  compared  with  the  enamel,  responding 
more  readily  to  an  irritant. 

Ulcerations  occurring  in  the  mouth  give  rise 
to  considerable  pain  and  discomfort,  and  as 
there  is  frequently  little  to  be  seen  by  the  patient, 
the  pain  is  often  attributed  to  other  causes. 
Perhaps  the  most  common  example  is  the 
ulceration  produced  in  the  soft  parts  by  undue 
pressure  of  a  denture,  or  the  ulceration  of  the 
tongue  caused  by  a  sharp  tooth.  Inspection 
of  the  mouth  in  both  cases  is  usually  sufficient 
to  determine  the  cause.  Ulcerative  stomatitis 
and  follicular  stomatitis  are  diseases  of  the 
mucous  membrane  of  the  mouth  in  both  of 
which  pam  is  a  prominent  symptom,  while  it 
is  usually  absent  in  syphilitic  ulcerations.  It 
would  be  beyond  the  scope  of  this  chapter  to 
deal  more  particularly  with  ulcerations  of  the 
mouth  as  a  source  of  pain  ;  suffice  it  to  say  that 
a  careful  examination  of  the  mouth  will  at  once 
convmce  the  practitioner  that  the  symptom  is 
not  due  to  such  causes. 

General  Periosteal  Inflammation  of  the  Jaw  is 
more  liable  to  attack  the  mandible  than  the 
maxilla.  The  disease  may  arise  from  a  neg- 
lected alveolar  abscess,  an  imjjacted  third  molar, 
sypliilis,  the  administration  of  certain  chugs 
(e.  g.  mercury),  or  inhalation  of  phosphorus 
fumes ;  or  it  may  occur  during  the  course  of 
certam  of  the  exanthemata,  following  injuries 
of  the  jaws,  as  a  sequel  to  ulcerations  withm 
the  mouth,  in  strumous  childi-en,  and  in  persons 
subject  to  rheumatism. 

The  earliest  .symptom  in  these  cases  is  an 
uneasy  sensation  in  the  teeth.  This  gradually 
becomes  Morse  and  the  least  pressure  on  them 
causes  excruciating  pain ;  the  pain  is  often 
\vorse  at  night.  There  is  redness  and  swelling 
of  the  face,  together  with  a  general  constitu- 
tional disturbance.  On  exammation  the  teeth 
are  found  to  be  raised  some\\hat  from  their 
sockets  and  loosened.  The  subsequent  course 
of  events  wOl  depend  to  a  great  extent  upon 
the  cause  of  the  inflammation.  Thus,  in  the 
periostitis  due  to  phosphorus  fumes,  or  to 
merci  rial  salivation,  extensive  suppuration  may 
result ;  in  strumous  patients  a  similar,  though 
usually  less  extensive,  necrosis  may  take  place  ; 
in  rheumatic  cases  suppuration  is  very  unusual. 
As  a  rule  general  thickening  of  the  jaw  occurs 
(15). 

In  the  preceding  paragraphs  the  possible 
causes  of  odontalgia  have  been  considered,  that 
is  to  say,  of  pain  in  which  the  patient  himself 
is  more  or  less  able  to  point  to  a  particular  tooth 
or  position  from  which  it  originates.     It  is  now 


440 


necessary  to  discuss  those  conditions  in  which 
the  pain  is  referred  to  some  position  or  localities 
other  than  its  seat  of  origin ;  but  it  nnist  not 
be  forgotten  that  the  causes  of  odontalgia  may 
also,  under  certain  conditions,  give  rise  to 
neuralgia  or  referred  pain — a  fact  that  has 
already  been  alluded  to. 

NEURALGIA 

General  Systemic  Conditions.— It  has  long  been 
recognized  that  there  are  general  constitutional 
conditions  which  in  their  course  predispose  the 
patient  to  neuralgia  of  the  trigeminal  nerve, 
e.y.  rheumatism,  syphilis,  influenza,  pregnancy, 
malaria,  anaemia,  and  neurasthenia.  These 
cases  present  many  difficulties  in  the  path  of  the 
dental  surgeon  seeking  to  arrive  at  a  correct 
diagnosis,  and  perhaps  illustrate  best  the  neces- 
sity of  the  specialist  and  the  physician  working 
hand  in  hand — a  point  also  emphasized  by  Risien 
Russell  at  the  meeting  of  the  British  Medical  As- 
sociation in  1905.  In  speaking  of  neuralgia  then, 
Russell  was  of  opinion  that  among  the  more  usual 
conditions  that  are  responsible  for  pain  referred 
to  the  teeth,  or  to  regions  comjilained  of  when 
the  teeth  are  at  fault,  may  be  placed  the 
neuralgia  experienced  in  anaemia,  and  that  due 
to  therheumatic  or  gouty  state,  or  to  malaria. 
Such  cases  have  yielded  to  treatment  appro- 
priate to  their  case  w  ithout  dental  treatment ; 
in  debilitating  diseases  also,  e.  (j.  influenza, 
measures  calculated  to  improve  the  nerve  tone 
are  more  effective  than  local  dental  treatment. 
Neuralgia  of  the  trigeminal  nerve  may  occur  in 
diabetes,  when  the  alisence  of  the  knee-jerk 
may  direct  attention  to  the  urine.  Among  the 
rare  causes  of  neuralgia  may  be  mentioned 
aneurism  of  the  internal  carotid  artery  and  facial 
hemiatrophy;  the  latter  may  have  its  other 
manifestations  preceded  by  pain  referred  to  one 
or  other  of  the  branches  of  the  trigeminal  nerve. 
In  some  cases  of  tabes  also  there  may  be  severe 
neuralgia  of  this  nerve  in  the  early  stages. 
Hysterical  and  neurasthenic  patients  may  com- 
plain of  odontalgia,  and  where  the  local  pain 
that  they  complain  of  is  excessive,  so  as  to  mask 
the  general  symptoms,  which  may  be  slight, 
innocent  teeth  may  be  extracted ;  the  patient 
being  often  anxious  to  obtain  sympathy  and 
notoriety.  Russell  cited  a  case  in  which  a 
hysterical  patient  produced  a  condition  of  one 
of  her  lower  limbs  that  induced  a  surgeon  to 
amputate  it ;  and  not  content  with  this  she 
produced  a  similar  condition  of  the  remaining 
limb,  which,  however,  led  to  the  fraud  being 
detected.  In  another  case  a  girl  was  able  to 
induce  surgeons  to  trephine  her  for  cerebral 
tumour  on  four  difTen^ut  occasions. 

As  an  example  of  how  a  physician  may  be 
misled  by  a  neurotic  patient,  and  of  the  import- 


ance of  continuing  to  search  for  organic  signs, 
in  spite  of  their  absence  when  the  patient 
first  comes  under  observation,  and  in  spite  of 
the  most  pronounced  evidences  of  functional 
disorder,  Russell  cites  the  following  case — 

"  I  was  once  consulted  in  regard  to  a  highly 
neurotic  man.  He  had  always  been  making 
much  out  of  little,  constantly  complaining  of 
this  or  that  aUment  wiih  the  result  that  his 
family  came  to  treat  his  complaints  with  little 
concern.  The  reason  that  I  was  consulted  was 
owing  to  a  ])ain  on  one  side  of  his  face,  which 
he  complained  of,  and  which  he  originally  had 
attrilnited  to  a  tooth.  He  had  first  consulted 
a  dental  surgeon,  who  was  induced  to  extract 
the  tooth.  As  the  pain  continued,  however,  he 
believed  that  the  operator  had  injured  hLs  jaw 
in  the  process  of  extraction,  and  that  if  this 
could  be  put  right  he  would  be  relieved  of  his 
pain.  Of  the  numerous  medical  men  he  saw 
one  sent  him  to  a  spa  for  anti-gouty  or  anti- 
rheumatic treatment,  in  the  belief  that  the 
neuralgia  was  of  the  so-called  '  gouty  '  or 
"  rheumatic  '  origin.  All  such  treatment  was, 
however,  to  no  purpose,  and  his  pam  continued. 
When  the  history  of  his  case  was  related  to  me 
it  seemed  certain  that  the  case  was  one  of  a 
particular  variety  of  neuralgia.  Wlien  I  ex- 
amined the  patient,  however,  I  had  to  give  up 
this  idea  as  the  case  was  obviously  not  of  this 
nature.  It  was  evident  that  the  man  was 
suffering  from  the  general  symjitoms  of  neuras- 
thenia in  combination  with  the  local  pain,  to 
account  for  which  I  could  discover  no  organic 
disease  of  the  nervous  system,  although  I 
examined  him  with  very  great  care,  notably  for 
intra-cranial  tumour.  Treatment  directed  to- 
wards neurasthenia  failed  to  relieve  him.  In 
the  process  of  exclusion  I  first  obtained  the 
assistance  of  a  dental  surgeon,  who  f)ronounced 
him  free  from  any  local  condition  of  the  teeth 
to  account  for  his  trouble.  Xext  an  ophthalmic 
surgeon  was  equally  unsuccessful  in  discovering 
any  cause  for  his  jiain.  Lastly.  I  sought  the 
assistance  of  a  .surgeon  skilled  in  the  examination 
of  the  nose  and  its  accessory  sinuses,  and  on  his 
transilluminating  the  maxillary  smus  on  the 
side  of  the  pain  a  shadow  was  seen  indicating 
the  presence  of  pus  or  some  solid  growth  in 
this  region.  Exploration  under  an  anae-sthetic 
resulted  in  the  evacuation  of  a  large  amount  of 
most  offensive  pus,  and  there  seemed  good 
reason  to  believe  that  the  poor  man's  sufferings 
were  at  an  end.  Instead  of  this,  however,  he 
continued  to  complain  of  the  old  pain,  and 
was  as  neurasthenic  and  miserable  as  ever. 
Further  exploration  resulted  in  some  of  the 
contents  of  the  sinus  being  removed  and  sub- 
mitted to  microscopic  examination,  when  it  was 
found  that  a  sarcomatous  growth  occupied  this 


441 


region.  The  maxilla  was  removed,  but  the 
growth  was  too  extensive  to  permit  of  tlie  hope 
of  more  than  temporary  relief. 

"  Tiiis  case  serves  to  illustrate  a  most  import- 
ant group  of  cases  in  which  disease  begins  in 
the  maxillary  sinus  without  being  in  any  way 
dependent  on  the  teeth,  but  in  which,  neverthe- 
less, tlie  dental  surgeon  is  the  per.son  fust  con- 
sulted. He  will  then  oftentimes  be  in  a  position 
to  direct  such  patients  into  the  appropriate  chan- 
nels when  the  disease  is  not  advanced,  and  when 
there  is  the  jjossibility  of  complete  removal  of 
a  growth  by  radical  surgical  intervention." 

Difflcult  Eruption  and  Malposition  of  Teeth. 
It  is  scarcely  a  matter  of  wonder  that  such 
conditions  should  give  rise  to  neuralgia,  but  the 
cause  assigned  for  the  pain  in  most  text-books 
is,  according  to  the  experience  of  the  wiiter  of 
this  chapter,  not  a  satisfactory  explanation, 
as  far  as  it  refers  to  the  theory  of  mechanical 
obstruction,  which  is  generally  advanced  to 
account  for  the  phenomena  m  connection  with 
the  eruption  of  a  third  lower  molar.  In  the 
event  of  that  tooth  lying  horizontally  in  the 
jaw,  and  by  pressure  causing  absorption  of 
the  second  molar,  and  consequent  exposure  of 
the  pulp  of  that  tooth,  the  sequence  of  events 
is  obvious  when  once  the  lesion  is  made  clear. 
But  in  several  cases  that  have  come  under 
observation  the  tliird  molar  has  failed  to  erupt 
when  its  2^o''ition  has  been  normal,  the  tooth 
not  overdue,  and  the  second  molar  had  been 
previously  removed.  These  cases  exhibited 
intense  neuralgia,  which  was  only  relieved  by 
the  extraction  of  the  third  molar,  so  that  it 
seems  that  the  mechanical  pressure  of  crowding 
is  not  by  any  means  a  necessary  condition  for 
the  jjroduction  of  pain,  or  of  the  non-eruption 
of  the  tooth.  The  following  case  will  illustrate 
this  point  :  "  A  young  gentleman,  aged  20, 
came  to  me  in  November,  1899  complaining 
of  a  severe  form  of  neuralgia.  He  stated  that 
he  first  experienced  it  two  years  previously 
after  a  bathe  early  in  the  year,  at  Easter.  At 
first  the  pain  was  of  an  intermittent  character ; 
coming  on  every  third  day,  it  would  gradually 
increase  m  intensity  and  then  die  away.  The 
pain  then  came  on  with  intervals  of  about  an 
hour  between  the  attacks ;  he  had  occasionally 
pain  at  night.  A  year  later  the  pain  came  on 
in  paroxysms,  more  intense  but  of  shorter 
duration.  He  improved  for  a  time  when  placed 
under  electrical  treatment  by  a  doctor  in  the 
country,  but  shortly  before  he  came  to  me  the 
pain  returned  with  greater  severity  than  before. 
HLs  troubles  usually  began  in  the  morning  after 
waking,  in  making  any  muscular  movement  of 
the  jaw;  he  got  through  his  breakfast  with 
difficulty,  but  improved  towards  the  middle  of 
the    day.     Light    touches    on    certain    points, 


rather  than  heavy  ones,  sufficed  to  bring  on  a 
paroxysm ;  after  this  was  over  he  could  touch 
these  spots  with  impunity.  The  patient  was 
always  able  to  foretell  a  paroxysm  by  a  feeling 
of  dryness  and  stiffness  of  the  lips,  and  a  sensa- 
tion of  tingling  down  his  arms  and  legs.  The 
paui  was  referred  to  all  the  usual  sites — infra- 
orbital, supra -orbital,  parietal  eminence,  just 
in  fi'ont  of  the  ear,  and  along  the  body  of  the 
mandible.  The  patient  .stated  that  the  pain 
generally  commenced  in  the  left  upper  canine, 
and  travelled  backwards  to  a  spot  in  front  of 
the  ear ;  but  occasionally  it  appeared  in  the 
other  foci  I  have  mentioned.  Before  coming 
to  me  this  patient  had  had  the  first  and  second 
molars  of  both  jaw  s  on  the  left  side  removed  m 
order  to  afford  him  relief.  As  the  case  was 
rather  an  obscure  one  I  had  a  consultation  with 
liis  physician,  and  various  remedies  for  neuralgia 
were  tried,  but  without  result.  Finally,  as  the 
third  lower  molar  showed  some  slight  signs  of 
erupting,  I  excised  a  tough  portion  of  gum  over 
it,  but  he  did  not  obtain  any  real  relief  till  my 
assistant  extracted  the  tooth  during  my  absence 
from  home.  Some  months  later  I  saw  this 
patient,  who  had  been  perfectly  free  from  pain 
for  a  month  after  the  removal  of  the  third  lower 
molar.  The  pain  then  returned  in  the  upper 
jaw,  and  was  evidently  connected  with  the 
eruption  of  the  third  left  upper  molar.  \Mien 
I  saw  him  the  upper  lip  was  swollen  and  dry, 
the  gums  were  painful  on  pressure,  most  of  the 
remaining  upper  teeth  were  jjainful  on  percussion, 
there  was  pain  on  light  pressure  up  the  left  side 
of  the  nose,  the  bowels  were  constipated,  and 
the  tongue  was  foul ;  the  pain  was  not  much 
affected  by  changes  of  temperature,  but  any 
sudden  muscular  movement  on  the  left  side 
brought  it  on  ;  when  talking,  therefore,  he  kept 
the  facial  muscles  on  the  left  side  curiously 
rigid.  This  patient  declined  to  part  with  his 
thu'd  upper  molar,  as  his  neuralgia  seemed  to 
become  less  severe  as  that  tooth  slowly  erupted. 
The  case  is,  I  think,  of  interest  as  showing  the 
amount  of  disturbance  these  teeth  can  occasion, 
even  when  they  are  not  unduly  late  in  appearing 
'  and  all  the  conditions  for  their  eruption  are 
favourable  (6)  ". 

Odontomes. — Pain  is  not  a  prominent  symp- 
tom in  the  clinical  history  of  these  tumours. 
In  their  first  stage  a  sense  of  uneasiness  in  the 
jaws  may  occur,  associated  with  neuralgic 
pam,  and  pain  may  be  complained  of  in  the  third 
.stage  when  inflammatory  symptoms  appear. 

Neuralgia  in  Edentulous  Patients. — This  has  been 
noticed  by  Ciross  of  Philadelphia^,  who  stated 
that  the  pain  suffered  by  the  patients  was  due 
to  terminal  filaments  of  one  or  other  division 
of  the  trigeminal  nerve  being  included  in  the 
ivory-like  bone  that  is  formed  on  the  alveolus 
of  some  edentulous  persons.     For  the  relief  of 


442 


the  pain  Gross  suggested  perforating  the  bone  in 
various  directions  with  a  drill,  or  excising  the 
affected  j)ortion,  which  can  generally  be  localized  I 
by  the  patient.  "  Some  years  ago  Sir  Thornley 
Stoker  requested  me  to  perform  this  operation 
for  an  old  lady,  but  as  it  was  not  considered 
advisable  to  give  the  patient  an  anaesthetic, 
I  was  unable  to  operate  ^\■itll  sufficient  thorough- 
ness to  ensure  success  (6)  ".  As  cases  of  this 
nature  are  not  very  common  the  following  notes 
may  prove  instructive  :  "  An  old  lady,  aged  75, 
was  sent  to  me  by  Dr.  Wallace  Beatty  with  a 
request  that  I  would  endeavour  to  clear  up  the 
cause  of  the  neuralgia  from  which  she  suffered 
severely.  I  found  tliat  she  dated  the  beginning 
of  her  trouble  to  a  chill  experienced  at  a  railway 
station  one  morning  Uvo  years  previously.  The 
pain  extended  from  the  right  ear  to  the  border 
of  the  lo%\er  lip  on  that  side.  Wlien  taking 
an  early  cup  of  tea  in  the  morning  she  suffered 
torture  in  endeavouring  to  drink  it.  Occasion- 
ally she  was  obliged  to  remove  her  lower  denture 
on  account  of  the  swelling  of  the  gum,  which 
after  a  time  subsided.  During  the  periods  of 
pain  and  swelling,  which  occurred  in  the  anterior 
portion  of  the  right  half  of  the  lower  jaw,  in  a 
position  roughly  corresponding  with  a  point 
mid'\\ay  between  the  mental  foramen  and  the 
symphysis,  the  superficial  nerves  of  the  chin 
and  lip  were  sensitive  to  touch,  and  the  pain 
in  the  spot  I  have  indicated  was  of  a  boring  or 
screwing  character.  On  examining  the  lower 
jaw  I  found  slight  cyst-like  swellings  on  the 
labial  alveolar  border,  corresponding  to  the 
positions  usually  occupied  by  the  canine  teeth ; 
and  I.  thought  I  could  detect  with  my  finger  the 
outlines  of  the  canines  Ijnng  horizontally  in  the 
jaw ;  this  was  better  marked  on  the  right  side. 
Dr.  Haughton  took  a  radiograph  for  me,  which 
gave  a  negative  result  as  far  as  teeth  were  con- 
cerned, but  which  showed  something  that  in  his 
opinion  was  either  periosteal  thickening  or  an 
odontome,  and  indicated  that  in  either  case 
an  operation  was  justified.  As  I  Avas  not  quite 
satislied  with  the  radiograph,  and  had  not  the 
faith  in  them  at  that  time  that  I  have  now,  I 
made  an  exploratory  examination  with  a  needle 
on  the  right  side,  and  succeeded  in  touching 
a  hard,  dense  substance,  which  was  not  alveolus, 
but  more  like  cementum,  with  an  outline  not 
unlike  a  tooth ;  this  tended  to  confirm  my 
original  opinion  that  this  fiatient's  neuralgia 
was  due  to  an  uneruptcd  canine.  The  jjatient 
being  placed  under  ether,  I  cut  down  on  the 
swelling  on  the  right  side,  the  gum  parted  A\'ith 
ease,  and  at  once  disclosed  a  glistening  white 
body,  so  like  a  tooth  that  the  anaesthetist 
exclaimed,  '  Oh  !  there  it  is.'  I  applied  an 
elevator  to  it,  thinking  it  would  shell  out  with 
ease,  but  found  it  impossible  to  stir  it.  Extend- 
ing my  incision  I  found  an  ivory  exostosis  of 


the  alveolus,  about  the  diameter  of  the  root  of 
a  canme  tooth,  extending  right  across  the  jaw, 
with  the  gum  lying  loosely  over  it.  As  it  was 
obviously  impossible  to  remove  it  except  by 
the  tedious  process  of  sawing  it  off  with  the 
engme,  and  as  I  did  not  care  to  subject  so  old 
a  patient  to  a  lengthy  operation,  I  contented 
myself  v,ith.  dusting  the  wound  with  iodoform. 
The  wound  healed  nicely  and  the  operation, 
although  unsuccessful,  inasmuch  as  I  did  not 
accomplish  what  I  intended,  had  the  happy 
result  of  completely  relieving  the  neuralgia  (6)  ". 

Inflammation  in  the  Maxillary  Sinus. — The 
amount  of  pain  in  these  cases  is  extremely 
variable,  and  really  depends  upon  whether  the 
natural  opening  into  the  middle  meatus  of  the 
nose  is  blocked  or  patent.  It  will  be  readily 
understood  that  in  the  rare  cases  where  there  is 
no  means  of  escape  for  the  accumulated  pus,  the 
distension  of  the  sinus  v,i\\  produce  pressure 
effects  on  the  maxillary  division  of  the  trigeminal 
nerve,  as  the  posterior  branch  of  the  posterior 
alveolar  supplies  the  lining  membrane  of  the 
maxillary  sinus.  Thus,  while  many  patients 
harbour  a  large  collection  of  pus  in  the  maxillary 
sinus  without  a  complaint  worth  mentioning, 
others  have  severe  neuralgic  pains  in  the  max- 
illa, imilateral  headache,  pressure  in  the  eye  and 
ear,  giddiness,  and  migraine  in  the  correspond- 
ing half  of  the  head  (20). 

In  this  connection  may  be  noticed  the  effects 
of  rhinitis,  coryza,  or  common  cold  in  the  head, 
upon  the  nerve  supply  of  the  upper  teeth,  pro- 
ducing tenderness  and  discomfort  amounting 
at  times  to  positive  pain.  In  a  general  catarrhal 
condition  of  the  mouth  all  the  teeth  may  become 
painful  and  loose,  more  particularly  those  whose 
periodontal  membrane  is  in  any  way  diseased ; 
this  condition  tends  to  pass  away  as  the  patient's 
general  condition  improves. 

Intra-cranial  Affections  of  Nerves. — It  is  im- 
portant that  the  dental  surgeon  should  recognize 
the  possibility  of  neui'algia  being  caused  by 
tumours  and  other  affections  of  the  brain ;  for 
in  tumours  at  the  base  of  the  brain  involving  the 
trigemiiaal  nerve,  and  in  gummatous  meningitis 
due  to  syjjhilis,  neuralgia  of  that  nerve  may  be 
an  early  symptom.  They  may  be  recognized 
long  after  the  pain  has  commenced  by  some 
anaesthesia  of  the  affected  side  of  the  face, 
paresis  of  the  temporal  and  masseter  muscles, 
which  may  become  atrophied,  and  paralysis  of 
the  external  pterygoid  muscle,  which  is  revealed 
by  the  deflection  of  the  chin  to\\ards  the 
affected  side  when  the  mouth  is  opened.  In 
some  of  the  sj-philitic  cases,  however,  there  may 
be  no  destruction  of  the  trigeminal  nerve ;  and 
consequently  anaesthesia  may  be  absent  (23). 

Neuralgia  Quinti  Major  {Epileptiform — Troiis- 
seau). — This  disease,  which  is  one  of  the  most 
distressing   maladies   that   the   dental   surgeon 


443 


may  be  called  upon  to  treat,  perhaps  because 
its  effective  treatment  lies  beyond  his  usual 
sphere  of  ^^■ork,  is  characterized  by  sudden  and 
violent  paroxysms  of  pain,  during  which  not 
only  the  facial  muscles,  but  often  those  of  the 
whole  body,  become  spasmodically  contracted. 
It  generally  occurs  late  in  life ;  sometimes  in 
edentulous  subjects,  when  its  true  nature  is  more 
likely  to  be  recognized.  The  importance  of 
forming  a  correct  diagnosis  when  the  case  is 
first  seen  cannot  be  overrated,  as  many  useful 
teeth  may  be  sacrificed  in  the  vain  attempt  at 
affording  relief.  The  neuralgia  generally  occurs 
on  one  or  other  side  of  the  face,  and  an  attack 
may  be  brought  on  by  any  movement  of  the 
muscles  of  mastication,  by  light  rather  than 
heavy  touches  on  the  face,  or  by  blasts  of  cold 
air ;  there  is  also  pain  in  the  tongue  on  the 
affected  side.  The  pain,  ^^hich  occurs  in  sharji 
stabs,  may  be  brought  on  by  eating,  drinking, 
speaking,  or  touching  the  angle  of  the  mouth. 
In  many  cases  hy[3ersecretion  is  present,  and  is 
said  to  be  diagnostic  of  the  organic  origin  of  this 
form  of  neuralgia  (18). 

AIDS    TO    DIAGNOSIS 

It  is  advisable  in  the  first  instance,  before 
looking  into  the  mouth,  to  obtaui  from  the 
patient  as  distinct  an  account  as  possible 
with  regard  to  the  present  attack  of  pain, 
putting  questions  when  it  is  necessary,  so  as 
to  exclude  irrelevant  matter.  It  is  of  import- 
ance to  ascertain  whether  the  pain  is  produced 
by  contact  with  food,  i.  e.  whether  the  tooth 
is  sore  to  touch,  or  irritated  by  the  jjressure 
of  food  in  a  cavity;  whether  hot  tea  or  cold 
water  induces  pain ;  whether  the  pain  comes 
on  at  any  definite  period  ;  whether  there  is  pain 
in  the  eye,  ear,  over  the  side  of  the  head,  or 
down  the  arm.  Examination  should  be  made 
to  find  whether  any  swelling,  enlargement  of 
glands,  or  discharge  into  the  mouth,  is  present. 
In  connection  with  the  patient's  narrative,  it  is 
%\ell  to  bear  in  mind  that  in  the  periodontal 
membrane  resides  the  entire  sense  of  touch  ^^■ith 
regard  to  a  tooth,  while  the  pulp  recognizes 
thermal  changes ;  that  is  to  saj',  a  pulp  will  at 
once  register  pauifully  any  variation  in  tem- 
perature, especially  if  that  pulp  be  at  all  hj'per- 
aemic,  but  will  be  unable  to  differentiate  between 
heat  and  cold  except  with  the  help  of  the  lips. 
The  tactile  sense  in  the  root-membrane  enables 
it  to  localize  an  injury,  while  the  pulp,  though 
responding  immediately  to  painful  stimuli,  is 
quite  unable  to  locate  them;  in  this  charac- 
teristic the  pulp  only  conforms  to  the  law  com- 
mon to  other  internal  organs  of  the  body,  which 
are  destitute  of  tactOe  sensation.  This  want 
of  localizing  power  on  the  part  of  the  pulp 
frequently  leads  patients  to  point  to  the  wrong 


tooth  as  the  source  of  paui  \^hen  a  pulp  is 
involved ;  moreover,  the  statement  of  the 
patient  that  certain  teeth  are  not  affected  by 
changes  of  temperature  often  requires  confirma- 
tion, as  patients  unconsciously  shield  these 
teeth  with  their  tongue  when  taking  anj-thing 
unusually  hot  or  cold  into  the  mouth. 

Having  obtained  all  possible  information 
from  the  patient,  the  dentist  is  noA\'  in  a  position 
to  make  a  thorough  examination  of  the  mouth. 
The  patient's  narrative  ^^■ill,  of  course,  indicate 
to  a  large  extent  where  this  examination  should 
begin.  With  a  mouth  mirror  and  fine  probe 
the  whole  surface  of  the  cro%Mi  of  a  suspected 
tooth  should  be  carefully  gone  over,  especially 
just  under  the  margin  of  the  gum.  A  lens  will 
often  be  found  useful  for  detecting  the  early 
beginnings  of  caries.  Waxed  floss  silk  passed 
between  the  teeth  v,-il\  sometimes  indicate  a 
cavity  ^^'hen  nothing  else  ^\•ill,  as  it  conveys  a 
sense  of  roughness  to  the  finger;  it  may  even 
be  at  once  cut  by  the  edge  of  a  ca\'ity.  For 
thermal  tests,  cold  may  best  be  applied  to  teeth 
by  means  of  cold  water  and  a  bulb-s>Tinge,  care 
being  taken  to  isolate  as  far  as  possible  the 
tooth  intended  to  be  tested  ;  and  a  large  heated 
burnisher,  or  better,  an  instnrment  with  a 
copper  bulb  at  its  extremity,  A\ill  be  found  useful 
for  convej-ing  heat.  It  is  ^^■ell  to  bear  in  mind 
that  teeth  in  ^\■hich  the  pulp  has  undergone 
degenerative  changes  respond  after  an  appreci- 
able interval  to  thermal  tests,  as  compared  with 
the  rapid  reaction  of  healthy  teeth. 

Percussion  with  a  heavy  steel  instrument 
affords  much  valuable  information,  and  should 
never  be  neglected ;  for  this  purpose  it  is  well 
to  bear  in  mind  that  light  taps  are  quite  as 
efficient  as  heavy  ones,  and  less  disagreeable 
to  the  patient.  Thus,  in  periodontal  mflamma- 
tion,  the  tooth  on  either  side  of  the  one  affected 
may  respond  to  percussion,  and  appear  almost 
equally  painful,  but  a  little  care  will  bring  out 
the  fact  that  the  centre  one  is  the  most  tender. 
It  is  also  useful  to  nin  the  index  finger  of  the 
right  hand  lightly  over  the  gum  about  the  level 
of  the  apices  of  the  roots  of  the  teeth,  when  a 
slight  s^A■elling  or  tenderness  over  a  particular 
tooth  w-ai  help  to  clear  up  the  diagnosis.  Per- 
cussion is  also  of  considerable  value  in  cases  of 
inflammation  of  the  pulp,  as  the  root-membrane 
is  frequently  involved  to  a  greater  or  lesser  ex- 
tent in  these  cases ;  but  if  the  pulp  has  been 
aflected  for  some  time  all  teeth  on  that  side 
may  be  more  or  less  sensitive  to  percussion. 
The  character  of  the  note  produced  by  percus- 
sion of  a  doubtful  tooth  may  advantageously  be 
contrasted  with  that  of  a  healthy  one,  and  the 
sensation  conveyed  by  the  percussion  mstru- 
ment,  of  tapping  against  a  pad  of  thickened 
membrane,  is  quite  distmct  from  the  clear  ring 
of  a  sound  tooth. 


444 


Colour  is  a  point  that  should  always  be  noted 
about  teeth  as  contrasted  with  their  fellows. 
Thus,  frequently  a  slight  opacity  ^\-ill  reveal 
the  beginning  of  a  cavity  that  the  probe  has 
not  detected,  and  a  trifling  difference  in  trans- 
hicency  \\ill  nlvny  that  a  pulp  is  not  quite 
healthy,  and  thus  lead  to  more  exhaustive 
tests  as  to  its  vitality.  A  good  mouth-mirror 
is  generally  sufficient  for  this  purpose,  but  the 
use  of  an  electric  mouth-lamp  is  also  valuable. 

It  is  perhaps  scarcely  necessary  to  add  that 
in  all  doubtful  cases  the  use  of  X-rays  will  afford 
the  practitioner  most  valuable  help,  by  giving 
trustworthy  information  about  pathological 
changes,  otherwise  unobtainable.  But  a  radio- 
graph, to  be  of  value,  must  be  correctly  inter- 
preted by  the  expert  who  takes  it ;  to  those 
unfamiliar  with  its  meaning  it  is  useless. 

In  the  following  case  the  use  of  novocaine  as 
an  aid  to  diagnosis  is,  as  far  as  is  known  to  the 
%mter,  original  :  "In  April,  1909,  a  young  lady 
consulted  me  for  constant  pain  on  the  right  side 
in  both  the  upper  and  lower  jaws,  with  occa- 
sional remissions.  The  jiain  was  better  at  night 
in  bed,  but  it  was  steadily  becoming  worse,  and 
while  it  affected  both  the  maxillary  and  mandi- 
bular divisions  of  the  trigeminal  nerve  on  the 
right  side,  it  extended  beyond  the  median  line 
in  the  mandible.  All  teeth  seemed  to  be  equally 
sensitive  to  percussion  and  thermal  tests,  but  if 
an\'thing  the  second  upper  molar  a  little  more 
than  the  rest.  My  suspicions  fell  on  the  second 
upper  premolar  as  the  possible  delinquent,  owing 
to  the  fact  that  it  was  a  shade  darker  in  colour 
than  the  others.  But  there  was  really  little 
to  choose  between  it  and  the  second  upper 
molar  ;  so  I  made  a  further  exhaustive  examina- 
tion of  all  the  teeth,  and  filled  a  small  cavity 
in  the  crown  of  the  third  right  ujiper  molar; 
taking  into  account  the  fact  that  the  neuralgia 
extended  Ijeyond  the  median  line  of  the  lo\\er 
jaw.  and  al.so  that  it  was  relieved  by  the  ad- 
ministration of  stimulants  and  aspirin,  I  came 
to  the  conclusion  that  the  neuralgia  was 
probably  the  result  of  anaemia  and  overwork 
for  an  examination ;  consecjuently  I  referred 
her  to  her  physician  before  deciding  on  local 
treatment.  Two  days  later  the  pain  was  more 
severe  all  day  in  the  regions  I  have  already 
indicated,  but  with  the  addition  of  an  occa- 
sional sharp  boring  pain  towards  the  right  eye. 
She  came  to  me  late  in  the  evening,  as  I  had  been 
away  from  town  all  day.  In  consecpience  of 
the  pain  in  the  infra-orbital  direction  I  decided 
to  remove  a  filling  from  the  second  right  upper 
premolar.  I  drilled  in  without  causing  any 
pain,  and  found  the  lining  of  cement  ^^■as  intact 
under  the  amalgam  filling.  There  was  a  slight 
trace  of  softening  at  the  cervical  edge,  which, 
on  being  touched,  gave  rise  to  a  severe  paroxysm 
of  pain.     As  it  was  not  yet  clear  whether  this 


tooth  or  the  second  molar  was  at  fault,  for 
purposes  of  diagnosis  I  decided  to  isolate  this 
tooth  «ith  novocaine,  as  I  thought  that  if  the 
pain  ^^•as  due  to  another  tooth  it  ^\ould  continue 
in  sjjite  of  the  premolar  being  anaesthetized,  but 
if  the  premolar  were  the  real  source  of  the  pain 
it  would  immediately  cease.  Accordingly  I 
injected  into  the  gum  on  each  side  of  the  pre- 
molar 0'125  of  a  gramme  of  novocaine,  with  the 
result  that  the  pain  immediately  ceased  and  my 
diagnosis  ^^■as  confirmed.  I  at  once  drilled  into 
the  pulp,  ^\hich  I  found  to  be  inflamed,  but 
without  the  formation  of  pulp-stones.  I  re- 
moved the  greater  portion  of  it,  but  was  afraid 
to  go  to  the  apex,  owing  to  the  complete  anaes- 
thesia produced  by  the  novocaine  ;  so  I  dressed 
the  root  ^\ith  pui'e  hot  carbolic  acid,  gave  the 
patient  some  phenacetin  and  cafEein,  and  sent 
her  to  bed.     The  result  \\"as  complete  relief  (4)  ". 

Head's  Areas. — As  any  enumeration  of  the 
aids  to  diagnosis,  in  cases  of  neuralgia,  would 
be  obviously  incomplete  if  it  did  not  include 
some  I'eference  to  the  important  work  done  by 
Henry  Head,  -what  are  familiarly  known  as 
"  Head's  Areas  "  vriW  now  be  considered. 

It  is  an  established  fact,  and  familiar  to  most 
dentists,  that  in  neuralgia  depending  on  dental 
causes  there  are  certain  points  of  anatomical 
interest  upon  the  head  and  face  where  the  pain 
is  of  maximum  intensity.  This  was  first  drawn 
attention  to  by  Valleix ;  but  more  recently 
Henry  Head,  in  a  series  of  jiapers  communicated 
to  the  Neurological  Society  and  published  in 
Brain,  has  most  ably  systematized  the  subject, 
and  has  shown  that  these  areas  of  skin  tenderness 
are  not  only  to  be  found  on  the  head  and  face, 
but  may  likewise  be  found  all  over  the  body, 
\N'here  they  correspond  to  visceral  disturbance. 
As  Head's  first  article  dealt  with  pain  and  ten- 
derness of  the  first  dor.sal  segment,  it  is  proposed 
not  to  do  more  than  allucle  to  it  here,  but  to 
start  at  once  from  the  point  where  his  observa- 
tions have  a  special  interest  for  dental  surgeons, 
viz.  in  the  region  of  the  head  and  face.  The 
system  that  he  adopted  in  determining  the 
areas  associated  with  any  particular  organ  of 
the  head  was  first  to  exclude  all  pain  and  tender- 
ness in  the  thorax  and  abdomen ;  then  to  note 
the  presence  or  absence  of  general  conditions, 
e.g.  anaemia;  and,  lastly,  to  exclude  the  dis- 
turbances of  organs  other  than  the  one  under 
observation.  After  determining  that  certain 
pain  and  tenderness  were  due  to  disturbance 
of  a  certain  organ,  he  noted  the  results  of  treat- 
ment of  that  organ.  Thus,  it  was  not  sufficient 
to  say  that  a  headache  was  due  "  to  the  eye  " 
or  "  to  the  teeth",  unless  the  direct  effect  was 
noted  by  treating  the  eye  or  removing  the  teeth. 

Head  found  that  each  organ  in  the  head 
stands  in  relation  to  one  or  more  areas  on 
the  surface.     To  these  areas  pain  is  referred, 


445 


and  over  them  the  skin  may  become  tender 
when  the  normal  condition  of  that  organ  is 
•disturbed. 

For  testing  superficial  tenderness  on  the  fore- 
head and  hairy  scalp,  where  there  is  a  firm  bony 
substratum,  the  blunt  end  of  a  pin  is  used; 
this  is  felt  as  a  blunt  touch  until  the  tender  area 
is  reached.  The  patient  then  complains  either 
that  the  touch  hurts  and  the  skin  is  "tender", 
"like  a  bruise  '',  or  he  may  say  that  he  is  being 
pricked.  In  carrying  out  these  tests  it  is 
necessary  to  use  a  pin  \\ith  a  spherical  head ; 
the  ordinary  pin  has  a  head  that  is  a  segment 
of  a  sphere  and  its  edge  may  be  definitely  sharp 
to  the  normal  skin,  unless  care  is  taken  not  to 
use  it  obliquely  to  the  skin  surface.  If  the 
tender  area  lies  over  the  hairy  scalp,  a  useful 
method  is  gently  to  pull  upon  or  lift  tlie  hair ; 
this  is  perfectly  painless  in  the  normal  human 
being,  but  becomes  painful  if  superficial  tender- 
ness is  present  over  the  scalp.  Thus  patients 
suffering  from  referred  pain  and  tenderness  \\  ill 
complain  that  their  hair  is  sore  when  tliey  brush 
it  in  the  morning.  On  the  cheeks  there  is  a 
clanger  that  the  head  of  the  pin  may  exert 
pressure  upon  tender  underlying  structures 
such  as  the  teeth,  and  it  is  therefore  advisable 
to  support  the  cheek  ^^•ith  the  finger  placed 
inside  the  mouth. 

Now  the  areas  that  are  concerned  w  ith  dental 
practice  are  eight  in  number.  These  it  is  hoped 
to  make  clear  with  the  help  of  a  couple  of 
diagrams  and  a  brief  description.  If  some 
general  idea  of  their  position  and  boundaries 
is  obtained,  it  will  render  subsequent  reference 
to  them  comparatively  simple. 
Head  has  named  these  areas — 

(1)  Fronto-nasal. 

(2)  Naso-labial. 

(3)  Temporal. 

(4)  Maxillary. 

(5)  Mandibular. 

(6)  Mental. 

(7)  Hyoid. 

(8)  Superior  laryngeal. 

(1)  Fronto-naml. — This  area  forms  a  racquet- 
shaped  patch,  with  the  larger  part  lying  over 
tlie  forehead.  It  extends  for  about  two  inches 
above  the  root  of  the  nose,  reaching  the  junction 
of  the  scalp  with  the  forehead.  It  meets  its 
fellow  of  the  opposite  side,  excepting  just  over 
the  root  of  the  nose.  At  the  level  of  the  eye- 
brow it  extends  out  for  about  an  inch  from  the 
middle  line  of  the  forehead.  A  downward  flap 
occupies  the  side  of  the  nose,  but  does  not  reach 
the  median  line ;  and  ends  below,  al)ove  the 
upper  part  of  the  ala  nasi. 

(2)  Xaso-Uthial. — This  area  lies  over  the  U])))er 
lip,  tip  and  under-surface  of  the  nose,  and  the 
cheek.     It  includes  part  of  the  lower  lip,  and 


extends  as  a  patch  on  tlie  cheek  as  far  back  as 
a  line  dropped  vertically  from  the  external 
canthus  of  the  eyje.  Its  limits  can  be  best  under- 
stood from  the  diagram. 


^/rO'^^rf'^^-" 


^^jf/u^/^y 


-*>f/VZ2'^(^XW 


Fig.  514. — Diagram  to  illustrate  the  area  of  tenderness 
as  mapped  out  by  Head  on  the  face  and  neck, 
front  view. 

When  tenderness  is  [jresent,  the  patient  com- 
plains ■■  that  his  upper  lip  is  swollen  and  tender, 
and  that  the  tip  of  the  nose  is  sore." 


-^^KiVra-'MSj^L 


**^Jr/^i^//r 


vAsO'^/iem 


Kic.  515. — Diagram  to  illustrate  the  "maxima' 
front  view. 


spots, 


(3)  Temporal. — Tliis  area  lies  directly  over 
the  temporal  fossa,  and  extends  upwards  for 
a  distance  of  three  to  four  inches  above  a  line 
joining   the   lateral    canthus   of   the   eye   with 


446 


the  upper  part  of  the  insertion  of  the  ear.  Its 
anterior  border  is  about  three  mches  from  the 
median  Ime  of  the  forehead,  and  about  half  an 
hich  in  front  of  a  vertical  Ime  drawn  up^^•ards 
from  the  uisertion  of  the  ear.  Its  breadth  is 
about  two  inches  at  the  widest  part.  The 
maximum  lies  in  the  temporal  fossa,  just  above 
the  upper  border  of  the  zygoma. 

The  pain  is  said  to  be  "  in  the  temple  ",  or, 
if  bUateral,  to  shoot  through  from  "  temple  to 
temple  ". 

(4)  Maxillary. — This  is  a  very  easy  area  to 
defuie.  It  lies  over  the  maxilla,  extendmg  as 
far  forwards  as  the  lateral  fold  between  the 
nose  and  the  cheek.  Its  upper  border  is  formed 
by  the  lower  margin  of  the  bony  orbit.  Its 
lower  border  is  a  curved  Ime  jommg  a  pomt  on 
the  clieek,  close  to  the  fold  between  the  ala  nasi 
and  the  upper  lip,  ^\■ith  a  point  just  posterior 
to  the  bony  orbit.  At  the  level  of  the  eyebrow 
the  apex  lies  about  three  inches  from  the  middle 
Ime  of  the  forehead.  To  this  area  also  belongs 
that  part  of  the  maxilla  contaming  the  pre- 
molar teeth,  together  with  a  portion  of  the 
hard  palate.  When  it  is  affected  by  other 
causes  than  caries  of  these  teeth  (e.  g.  lesions 
of  the  eye),  these  teeth  may  ache,  and  the  hard 
palate  in  their  neighbourhood  may  be  tender. 

(5)  Mandibular. — This  area  is  also  roughly 
triangular,  and  lies  over  the  coronoid  process, 
and  the  ranuis  and  part  of  the  body  of  the  man- 
dible. Below,  it  extends  as  far  forward  as  a  line 
dropped  vertically  from  the  external  canthus  of 
the  eye.  The  apex  of  the  triangle  lies  about  half 
an  inch  in  front  of  the  insertion  of  the  ear. 
From  this  point  the  posterior  border  dips  back 
to  include  the  tragus  of  the  ear,  and  then  swings 
forwards  and  downwards  in  front  of  the  posterior 
border  of  the  mandible.  The  anterior  border 
of  this  area  abuts  on  the  posterior  border  of 
the  maxUlary  area,  except  at  its  lower  portion. 
The  maximum  spot  of  this  area  lies  about  on 
a  level  with,  and  a  little  in  front  of,  the  tragus 
of  the  ear. 

The  pam  is  referred  to  the  cheek,  just  in  front 
of  the  ear.  This  area  becomes  tender  with 
disease  of  the  last  two  molars  of  the  maxilla. 

(6)  Mental. — This  area  swings  almost  directly 
back  from  the  angle  of  the  mouth  to  a  point 
on  a  line  drawn  vertically  downwards  from 
the  lateral  canthus  of  the  eye.  Thence  it  drops 
slowly  to  a  point  on  the  posterior  body  of  the 
lower  jaw,  about  three  inches  from  the  middle 
line.  It  then  runs  forwards  along  the  fold 
separating  the  chin  from  the  neck.  In  front  it 
does  not  include  the  lo\\er  lip  or  that  part  above 
the  elevation  of  the  cliin. 

When  tliis  area  is  affected,  the  anterior  one 
and  a  quarter  mches  of  the  tongue  are  tender 
on  the  side  affected.  This  area  is  tender  in 
connection  with  disease  of  the  anterior  part  of 


the  tongue,  and  of  the  mcisor  and  canine  teeth 
of  the  mandible. 

(7)  Hyoid. — This  area  lies  partly  over  the 
ramus  of  the  mandible,  and  partly  behmd  its 
posterior  border.  The  limits  are  best  gathered 
from  the  diagram.  Posteriorly  it  runs  up  on 
to  the  mastoid,  and  hence  superficial  tenderness 
over  this  area  may  give  rise  to  fictitious  "  mas- 
toid tenderness  ".  The  lobule  of  the  ear  is  also 
tender.  The  anterior  border  of  this  area  lies 
m  front  of  the  lobule,  but  does  not  include  the 


Fig.  51(1. — Diagram  to  illustrate  the  area  of  tenderness 
as  mapped  out  by  Head  on  the  face  and  neck,  side 
view. 

tragus,  whicli  belongs  to  the  mandibular  area. 
The  posterior  portion  of  the  meatus  is  intensely 
tender,  and  the  insertion  of  an  aural  speculum 
will  give  much  pain.  There  is  also  tenderness, 
as  a  rule,  over  the  edge  of  the  tongue.  The 
maximum  spot  lies  just  behmd  and  below  the 
angle  of  the  mandible.  A  second  most  import- 
ant maximum  lies  ui  the  external  acoustic 
meatus. 

The  patient  complains  of  pain  in  the  ear,  and 
of  pain  ■'  just  behind  the  jaw " ;  hence  the 
lialjitual  complaint  of  pain  in  the  ear  with 
affections  of  tlie  tonsils,  side  of  the  tongue,  and 
molar  teeth  of  the  mandible  ;   and  also  the  pain 


447 


in  the  ear  so  commonly  met  witli  in  diphtheria. 
This  referred  pain  is  liable  to  lead  to  errors  of 
dia(;nosis,  as  the  membrana  tympani  has  Ijeen 
perforated  without  relief,  when  the  fault  lay 
in  the  molars  of  the  mandible. 

(8)  Superior  Laryngeal. — The  area  next  below 
the  hyoid  is  roughly  triangular  in  shape.  The 
apex  of  the  triangle  reaches  posteriorly  to  a  line 
dropped  vertically  from  the  posterior  attachment 
of  the  ear.  The  posterior  part  of  its  lower 
border  lies  just  behuid  the  anterior  border  of 
the  sterno-mastoid,  and  thence  swings  dowii- 
wards  ajid  forwards  to  the  level  of  the  lower  part 


si//)rfi/curijiffKva;tt 


Fk;.  517.- 


-Diagramto  illustrate  the  "maxima  "  spots, 
side  view. 


of  the  thyreoid  cartilage .  The  upper  border  runs 
forwards  from  the  posterior  angle,  and  just  laps 
up  on  to  the  extreme  posterior  border  of  the 
body  of  the  mandible.  It  then  skirts  the  fold 
between  the  chin  and  neck,  and  seems  to  meet 
its  fellow  on  the  other  side  about  the  thyreo- 
hyoid  space.  From  this  anterior  sujierior  angle 
the  base  of  the  triangle  curves  downwards  to 
meet  the  termination  of  the  lower  border  a  little 
to  one  side  of  the  middle  line  at  the  level  of  the 
lower  border  of  the  thjTcoid  cartilage. 

If  this  area  is  alTected  by  any  cause  \\hatever, 
the  patient  complains  that  he  has  difficulty  in 
swallowing.     Tlic  paui  is  said  to  be   "  m  the 


throat  ".  and  the  patient  points  to  the  situation 
of  the  maximum  spot,  which  is  just  in  front  of 
the  anterior  border  of  the  sterno-mastoid  at  the 
level  of  the  thyreoid  prominence. 

Tliough  anatomically  a  small  area,  and  one 
that  has  been  crowded  in  the  course  of  develop- 
ment, it  is  stUl  functionally  important,  for 
into  it  refer  the  third  molars  of  tlie  mandible, 
and  the  jjosterior  part  of  the  dorsum  of  the 
tongue. 

The  following  table  exhibits  the  teeth  of  the 
maxilla  and  mandible,  and  the  areas  to  which 
pain  is  referred  in  the  event  of  their  being 
diseased  : — 

Teeth. 

(1)  Uppc?r  incisors.] 

(2)  Upper  canines  and  fii'st 

premolars. 

(3)  Upper  second  premolars. 

(4)  Upper  first  molars. 

(5)  Upper  second  molars. 

(6)  Upper  third  molars. 

(7)  Lower   incisors,   canines, 

and  first  premolar.^. 

(8)  Lower   first   and   second 

molars. 

(9)  Lower  third  molars. 
(10)  Lower  second  premolars. 


Areas. 
Fronto-nasal. 
Naso-labial. 

Temporal,   also   Maxil- 
lary. 
Maxillai'y. 
ManiUI)ular. 
Mandibular, also  Hyoid. 
Mental. 

Hyoid.     Pain  in  ear, 
edge  of  tongue  tender. 

Superior  Laryngeal. 

(Doubtful)     Mental    or 
Hyoid. 


Anatomy. — Li  order  to  understand  how  these 
skin  areas  are  associated  witli  visceral  disturb- 
ance, it  will  be  necessary  to  refer  briefly  to  some 
anatomical  facts  connected  with  the  nervous 
system.  These  are  taken  from  Prof.  Dixon's 
admirable  address  on  the  "  Distribution  of  the 
Perijjheral  Nerves  ".  The  late  Prof.  His  pub- 
lished some  papers  in  which  he  drew  marked 
attention  to  the  fact  that  in  the  early  human 
embryo  the  nerves  run  almost  straight  courses 
from  thek  origins  to  their  terminations.  He 
showed  very  clearly  that  the  complications 
found  in  the  courses  of  the  nerves  in  the  adult 
arose  gradually,  and  were  due  to  unequal  rates 
of  growth  m  the  various  parts  of  the  developing 
embryo,  and  to  the  consequent  bendings  of  the 
tissues  and  the  displacements  of  the  organs 
during  their  development.  He  conclusively 
proved  it  to  be  possible  to  demonstrate  that 
the  various  organs  and  parts  of  the  body  in 
the  embryo  receive  their  nerve  supply  from  the 
nerves  belonging  to  the  region  in  which  the 
organs  or  parts  originate,  and  that  the  complica- 
tions in  the  courses  of  the  nerves  in  the  adult 
are  due  to  the  fact  that  the  various  organs  and 
parts  during  then-  development  often  become 
removed  far  from  the  regions  where  they  are 
first  found. 

It  has  been  established  that  in  the  lower 
vertebrates  all  the  spinal  nerves  are  built  upon 
the  same  plan,  and  that  each  nerve — formed  by 


448 


the  junction  of  its  two  roots — divides  into  a 
dorsal  and  a  ventro-lateral  sub-division.  The 
dorsal  sub-division  has  been  traced  to  the  skin 
and   muscles   of   the    back,    while   the    ventro- 


Abducent  nerve 
Trigeminus 
Optic  cup  and  len: 
Trochlearis 


Within  recent  years  surgeons,  by  removal 
of  the  semilunar  ganglion  and  the  trigeminal 
nerve  roots  in  cases  of  trigeminal  neuralgia,  have 
afforded  opportunities  for  precise  observations 

concerning  the 

Hind-brain 

Acoustic  nerve 
I        otic  capsule 

Second  post-oral  cleft 

Glossopharyngeal  nerve 
ird  post-oral  cleft 

Auricular  branch  of  vagus 


Telencephalfii 


Oculo-motor  ner^-e*-^ 


Froriep's  ganglion 


Ophthalmic  nerve  ■" 


Diencephalon 


Eoot  and  trunk  of 
the  first  cervical 
spinal  nerve 
_/ 

Accessorius  [nerve  anaesthesia; 

p'l  runk  of  2nd  cervical  spinal 
-Hypoglossal  nerve 


actual  distri- 
bution of  this 
nerve  in  man. 
Ki'ause,  Lynn 
Thomas,  Gush- 
ing, and  others, 
have  in  such 
cases  carefully 
mapped  out 
the     areas    of 


Roots  and  trunks  of 
cfivieal  spinal 
nerves  3-7 


Olfactory  bulb      / 
Fronto-nasal  process 

Nasal  pit  [ 
Ocular  fissure 
Lateral  nasal  process 
Maxillary  nerve 
Maxillarv  process 
Mouth  cleft 
Mandibular  trunk 
Mandibular  arch 


Fourth  post -oral  < 
I  Vagus  nerve 
Second  branchial  arch 


lea 


Fig.  518.- 


First  branchial  arcli 
Thyreo-liyoid  arch 
Facial  nerve 
Hyoid  arch 
First  post -oral  cleft 
-Hivnian  embryo,  four  weeks  old,  showing  the  distribution  of  the  cerebral  and 
spinal  nerves.     From  a  drawing  by  Professor  His.     (Dixon.) 


lateral  has  been  shown  to  divide  into  a  larger 
and  more  superficial  branch  for  the  body  wall, 
and  a  smaller,  deeper,  visceral  branch  for  the 
supply  of  the  internal  organs. 

It  has  been  shown  that  this  type  of  spinal 
nerve  distrilnition  occurs  also  in  the  embryo, 
of  higher  mammals,  including  man  ;  and  it  is 
kno\\-n  that  each  spinal  or  segmental  nerve  sup- 
plies the  various  structures  that  arise  from  the 
segment  to  which  the  nerve  belongs — skin, muscle, 
viscera,  and  probably  also  blood-vessels. 

In  the  head  there  are  motor  and  sensory 
nerves,  and  some  of  these,  at  all  events  in 
the  embryo,  seem  to  arise  in  fundamentally  the 
same  manner  as  the  segmental  nerves  of  the 
trunk.  It  would,  therefore,  be  of  interest  to 
inquire  whether  it  has  been  found  possible  to 
establish  for  the  cerebral  nerves  a  tyi^e  of  distri- 
bution at  all  comparable  with  that  which  has 
been  proved  to  exist  in  the  case  of  the  spinal 
.segmental  nerves.  This  is  a  suliject  that  has 
received  nuich  attention  ;  and  most  conflicting 
views  are  held  concerning  it.  Although  certain 
of  the  cerebral  nerves  at  first  sight  do  appear  to 
resemble  spinal  nerves,  both  in  regard  to  their 
formation  and  their  mode  of  attachment  to 
the  brain,  Di.xon  is  of  opinion  that  it  would 
seem  to  be  wiser,  with  present  knowledge,  to 
be  careful  not  to  push  the  comparison  too  far, 
and  for  the  most  part  to  be  content  to  consider 
the  cerebral  nerves  by  themselves. 


and  the  most 
recent  papers 
of  Gushing  on 
this  subject 
probably  give 
the  most  ac- 
curate pictures 
as  yet  available 
of  the  sensory 
distribution  of 
this  great 
nerve,  both  on 
the  face,  and 
in  the  mouth, 
nose,  and  pharynx.  It  is  most  satisfactory  to 
note  that  as  regards  the  surface  of  the  face 


Kic.  519. — Cutaneous  distribution  of  the  trigeminal 
nerve  in  man  as  determined  by  Gushing.  Over  the 
dotted  areas  sensation  was  not  completely  lost, 
but  painful  sensations  were  interpreted  as  tactile 
sensations.     (After  Professor  Di-xon.) 

and  head,  the  minute  anatomical  dissections  of 
Frohse  enabled  him  almo.st  quite  accurately  to 
map  out  the  sensory  field  of  the  trigeminal  nerve  ; 


449 


and  Gushing  remarks  that  the  outline  given  in 
one  of  Frohse's  figures  is  practically  the  counter-  i 
part  of  the  skhi-field  demarcated  in  nearly  all 
his  cases  of  trigemuial  neurectomy. 

A  consideration  of  these  facts  sliows  that 
there  is  a  close  analogy  between  the  trigeminal 
and  a  segmental  nerve.  The  trigemmal  nerve  is 
distributed  to  the  internal  organs  of  the  mouth — ■ 
teeth,  tongue,  etc.,  and  sends  branches  to  supply 
the  skin  and  the  face ;  so  that  in  cases  of 
neuralgia  or  referred  paui  it  might  naturally 
be  expected  that  the  areas  of  tenderness  traced 
out  by  Head  would  be  found.  It  will  be  noticed 
that  the  area  of  anaesthesia  mapped  out  by 
Gushing  for  the  trigeminal  stops  at  a  well- 
defined  Ime,  which  lies  over  the  ramus  of  the 
mandible.  The  curious  alteration  in  sensation 
that  has  been  observed  posterior  to  this  line  in 
cases  where  the  semilunar  ganglion  has  been  re- 
moved, may  be  accounted  for  by  considering  the 
nerve  supply  of  this  region ;  for  the  skbi  over 
the  angle  of  the  jaw  is  supplied  by  the  great 
auricular  nerve,  and  communicating  branches 
of  the  trigeminal,  facial,  and  glosso-pharyngeal 
nerves.  This  would  also  explaui  how  the 
mandibular,  hyoid,  and  superior  laryngeal  areas 
become  affected  by  dental  causes. 

In  investigating  the  relations  between  the 
different  teeth  and  then-  areas  of  superficial 
tenderness,  it  is  found  that  these  organs  stand 
in  a  curious  position  compared  with  other 
organs  of  the  body,  in  that  they  lie  in  a  cavity 
where  the  necessary  conditions  for  the  develop- 
ment of  powers  of  localization  are  fulfilled.  It 
is  for  this  reason  believed  that  a  local  pam  will 
persist  in  the  teeth  later  than  in  any  other  organ 
of  the  body. 

The  first  stage  of  caries  of  a  tooth  may  be 
roughly  said  to  consist  of  the  removal  of  the 
enamel  and  excavation  of  the  underhmg  den- 
tine. During  this  process  pain  may  or  may  not 
be  present ;  but  provided  the  dentme  is  affected, 
pain  can  generally  be  elicited  by  stimulation. 
The  most  effectual  stimulus  in  these  conditions 
is  heat  and  cold ;  for  in  many  cases  \\  here  a 
carious  portion  may  be  cut  away  without  pain, 
a  jet  of  hot  or  cold  water,  or  the  blast  of  the 
chip-sjTinge,  will  produce  a  twinge  of  pain. 

Xow  as  long  as  the  pulp-cavity  is  not  exposed 
the  pain  remains  local.  The  patient  complains 
of  an  aching  tooth,  and  will  point  to  the  one 
affected.  The  pain  may  "  dart  and  shoot ", 
but  the  darting  and  shooting  are  practically 
confined  to  the  aching  tooth.  Local  stimulation 
produces  local  pain.  Neuralgia  is  absent,  and 
no  tenderness  appears  in  the  skin  of  the  face. 
In  this  stage  the  pain  jjroduced  by  the  tooth  is 
exactly  analogous  to  tliat  produced  by  injuries 
to  the  conjunctiva  or  outer  layer  of  the  cornea. 
It  is  purely  local,  and  points  to  the  seat  of  the 
injury. 
15 


If,  however,  the  pulp-cavity  is  exposed,  the 
paui  alters  in  character  and  distribution.  It 
starts  ui  the  affected  tooth,  and  darts  and  shoots 
into  the  face,  forehead,  neck,  or  ear.  Each 
stab  of  pain  lasts  a  few  moments  only,  to  be 
followed  more  or  less  rapidly  by  a  second  twinge. 
This  is  the  well-known  "neuralgia",  caused  by 
affections  of  the  teeth. 

On  testmg  the  face  or  teeth  during  the 
"  neuralgia  "  some  one  or  more  of  the  areas 
described  will  be  found  more  or  less  tender.  On 
the  face  thLs  tenderness  is  superficial,  but  parts 
of  the  jaw,  mouth,  or  tongue  may  be  tender  at 
a  distance  from  the  affected  tooth,  owing  to 
their  intimate  connection  with  the  distribution 
of  these  areas.  Thus  teeth  at  a  distance  from 
the  one  affected  may  ache  and  be  tender  to  the 
touch.  The  tender  areas  are  not  developed 
until  the  neuralgia  has  lasted  several  hours,  and 
when  a  test  is  made  for  them  the  patient  may 
refer  the  pain  to  a  particular  spot  on  the  face 
or  head,  saying  '"  When  you  touch  me  there  it 
seems  to  make  my  tooth  worse".  Tenderness 
usually  ceases  within  twenty-four  hours  after 
the  removal  of  the  tooth,  or  it  may  be  absent 
if  the  pain  has  ceased  for  several  hours. 

For  diagnostic  purposes  the  patient's  account 
alone  may  frequently  be  of  value ;  for  referred 
pain  is  localized  by  the  patient  in  the  maximum 
spot  or  spots  of  the  tender  area  affected.  Thus, 
given  a  knowledge  of  the  distribution  of  the 
tender  areas  and  their  "  maxima  ",  it  is  easy  to 
determine  to  what  area  the  referred  pain  must 
have  belonged,  and  thus  indirectly  to  arrive  at 
the  diseased  tooth.  For  instance,  if  the  patient 
says  that  he  has  had  ear-ache,  he  has  probably 
suffered  from  the  referred  pain  that  is  frequently 
associated  with  tenderness  in  the  hyoid  area. 
Now  tenderness  here  is  associated  with  disease 
of  the  second  premolar  and  first  and  second 
molars  of  the  mandible ;  and  thus  it  is  possible 
to  argue  back  that  the  patient  with  referred 
pain  in  the  ear  is  suffering  from  disease  of  one 
of  these  teeth. 

Head's  theories,  and  his  explanation  of  these 
tender  areas,  are  certainly  fascinating,  but  up 
to  the  present  they  do  not  appear  to  have  given 
the  results  that  Head  so  confidently  predicted. 
This  may  be  partly  due  to  the  fact  that  they 
have  not  been  sufficiently  tested,  and  the  areas 
carefully  examined  for,  in  neuralgic  cases. 
Whether  they  will  be  of  real  value  as  an  aid  to 
diagnosis  will  depend  upon  the  results  obtained 
from  the  examination  of  a  fairly  large  number 
of  cases,  which,  as  far  as  the  writer  is  aware, 
has  not  been  attemjjted  up  to  the  present. 
Notwithstanding  the  lack  of  successful  dental 
cases,  and  that  clinical  physicians  have  reported 
that  their  results  have  not  been  encouragmg, 
there  is  no  doubt  that  the  subject  will  amply 
repay  further  investigation,  even  if  it  leads  to 


450 


nothing  more  than  a  better  acquaintance  with 
the  nerve-supply  of  the  head  and  face  ;  it  is  not 
unlikely  that  it  may  demonstrate  the  existence 
of  a  valuable  aid  to  diagnosis  m  obscure  cases  of 
neuralgia.  A.  W.  W.  B. 

BIBLIOGRAPHY 

(1)  AcLAND,  W.  R.     Notes  on  Some  Causes  of  Neur- 

algia.    Brit.  Med.  Jour.,  1907,  p.  1499. 

(2)  Amoore,  J.  S.     Dental  Record,  1900,  Vol.  XXVI, 

p.  73. 

(3)  Andrews,  E.     Two  Cases  of  Removal  of  Gasse- 

rian  Ganglion.      Brit.   Dent.  Jour.,  1892,  Vol. 
XIII,  p.  620. 

(4)  Baker,  A.  W.  W.     A  Case  of  Neuralgia.     Dental 

Record,  1910,  Vol.  XXX,  p.  217. 

(5)  Baker,  A.  W.  W.    A  Clinical  Lecture  on  "Head's 

Areas".     Med.  Press,  June  22,  1910. 

(6)  Baker,   A.   W.    W.     Neuralgia.     A  Communica- 

tion to  the  Dublin  Biological  Club. 

(7)  Baldwin,    H.     Neuralgia.     Trans.    Odoni.    Soc, 

1890-1,  Vol.  XXIII,  p.  84. 

(8)  Black,  G.  V.     Litch's  American  System  of  Den- 

tistry.    Vol.  I,  p.  923. 

(9)  Brownlie,  J.  D.  Odontalgia.  Dental Record,Ma,Tc\i, 

1910,  Vol.  XXX,  p.  168,  Discussion,  p.  195. 

(10)  BuECHARD,  H.  H.     Dental  Pathology,  p.  500. 

(11)  Dixon,  A.  F.     The  Distribution  of  the  Peripheral 

Nerves.     Dub.  Jour.  Med.  Science,  Feb.,  1905. 


(12)  Fereier,  Sir  David.     On  Some  Relations  of  Fifth 

Cranial   Nerve.     Trans.   Odont.   Soc,    1889-90, 
Vol.  XXII,  p.  225. 

(13)  Hayman,   C.   A.     Neuralgia.     Brit.   Dent.   Jour., 

1900,  \  ol.  XXI,  p.  721. 

(14)  Head,   H.     Disturbances   of   Sensation   and   the 

Pain  of  Visceral  Disease.     Brain,  1894. 

(15)  Heath,   C.     Injuries  and    Diseases   of    the  Jaws. 

4th  ed.  Chap.  XII,  p.  89. 

(16)  Hopewell-Smith.     Histology  and  Patho-Histology 

of  the  Teeth. 

(17)  HoRSLEY,    Sir    Victor.      Neuralgia.     Brit.    Med. 

Jour.,  Sept.  9,  1905. 

(18)  Marshall,  J.     Clu-onic  Neuralgia  of  Upper  Lip. 

Brit.  Dent.  Jour.,  1890,  Vol.  XI,  p.  34. 

(19)  Mummery,  H.     Brit.  Med.  Jour.,  Sept.  9,  1905. 

(20)  Partsch,  C.     Diseases  of  the  Antrum.     Handbuch 

der  Zahnheilkunde.     Vienna,  1892. 

(21)  RiLOT,    C.    F.     Neuralgia.     Trans.    Odont.    Soc, 

1890-1,  Vol.  XXIII,  p.  84. 

(22)  Rose,  W.     Removal   of   Gasserian  Ganglion   for 

Severe  Neuralgia.    Brit.    Dent.  Jour.,  1890,  Yo]. 
XI,  p.  740. 

(23)  Russell,  Risien.     Neuralgia.     Brit.  Med.  Jour., 

Sept.  9,  1905. 

(24)  Salter,  S.  J.  A.     Dental  Pathology  and  Surgery. 

(25)  Smale,  M.  &  CoLYER,  J.  F.     Diseases  and  Injuries 

of  the  Teeth. 

(26)  Tomes,  C.  S.  &  Nowell,  W.  S.     Odontalgia  and 

Neiu-algia.     A  System  of  Dental    Surgery,   5th 
ed.,  p.  663. 


CHAPTER  XXVII 

TREATMENT  OF  THE  DENTAL  PULP 


The  normal  human  tooth  contains  a  live  jnilp. 
The  function  of  the  pulp,  according  to  a  few  his- 
tologists,  has  ceased  when  the  tooth  is  fully 
developed ;  upon  this  hypothesis  many  practi- 
tioners do  not  liesitate  to  devitalize  the  pulp 
of  a  tooth  for  reasons  that  others  would  consider 
unjustifiable.  The  experience  of  the  great 
majority  of  practitioners  is  that  a  pulp  should 
not  be  devitalized  unless  there  is  no  hope  of 
retaining  it  permanently  in  a  normal  vital 
condition.  It  may  be  justifiable  sometimes 
to  attempt  to  retain  the  vitality  of  a  pulp,  even 
for  a  few  years,  if  the  tooth  is  not  fully 
developed. 

Not\\-ithstanding  the  arguments  set  fortli 
by  histologists  and  some  radical  practitioners, 
observation  shows  tliat  both  the  enamel  and 
the  dentine  of  a  tooth  that  has  lost  its  pulp  lose 
in  strength  and  endurance.  The  earlier  in  life 
a  tooth  loses  its  pulp,  the  fewer  years  it  will 
last.  A  tooth  that  loses  its  pulji  before  the 
normal  closure  of  the  apex,  or  shortly  after 
its  eruption,  does  not  usually  give  many  years 
of  useful  service ;  both  the  tooth  structure  and 
the  periodontal  membrane  lose  in  strength  and 
in  endurance.  Teeth  that  have  lost  their 
pulps  are  not  so  useful  for  mastication  as  those 
with  live  pulps.  Black  (1 )  has  shown  that  molars 
upon  which  a  patient  could  bring  to  bear  in 
closure  a  pressure  of  over  two  hundred  pounds 
could  only  withstand  a  jiressure  of  less  than 
a  hundred  pounds  after  devitalization  of  the 
pulji.  Crowns  supported  by  roots  of  teeth 
that  have  lost  their  pulps,  and  bridges  sup- 
ported by  abutments  without  pulps,  are  not 
as  useful  for  mastication  as  if  the  pulps  had 
remained  alive.  WliOe  all  teeth  do  not  dis- 
colour equally  when  their  pulps  have  been 
devitalized,  yet  sufficiently  large  numbers 
discolour  badly  enough  to  make  the  careful 
operator  consider  the  possibilities  of  a  darkened 
tooth.  The  degree  of  discoloration  depends 
largely  upon  the  mode  of  operating,  but, 
perhaps,  almost  as  much  upon  the  striicture 
of  the  tooth.  The  younger  the  patient  the 
greater  are  the  possibilities  for  discoloration  ;  no 
conscientious  operator  lightly  undertakes  the 
devitalization  of  the  pulp  of  an  anterior  tooth 
for  a  young  patient.  It  is  well  recognized  to-day 
that  the  cases  of  devitalization  that  give  the 
best  results  are  those  of  single-rooted  teeth  in 


mature  persons.  No  preservative  yet  dis- 
covered vnll  keep  dead  pulp  tissue  free  from 
infection  in  a  root-canal;  as  the  difficulties  of 
removing  all  the  pulp  tissue  from  root-canals 
increase,  so  do  the  chances  for  ultimate  failure. 

The  foregoing  reasons,  and  those  of  the  pain, 
discomfort,  loss  of  time,  and  the  expense,  are 
enough  to  dissuade  the  dentist  from  needlessly 
devitalizing  a  dental  pulj). 

Strong  as  the  reasons  are  for  retaining  a 
pulp  alive  ^^•here  it  is  indicated,  yet  they  are 
not  as  strong  as  those  for  devitalization  where 
such  an  oi^eration  is  demanded.  The  pain  and 
discomfort,  the  ijossibility  of  an  alveolar 
abscess  and  its  consequences,  are  sufficient  to 
cause  the  dentist  to  use  all  the  knowledge 
and  experience  obtainable  before  deciding  upon 
his  course  of  action.  In  few  cases  is  the  den- 
tist's misjudgement  fraught  with  such  bad 
consequences  as  in  not  devitalizing  a  pulp  that 
should  be  devitalized. 

MANAGEMENT  OF  PULPS  ALMOST  EXPOSED, 
OR  EXPOSED  WHEN  THE  OPERATOR  BE- 
LIEVES THAT  CONSERVATION  IS  DESIRABLE 

Dental  Caries. — It  can  be  laid  down  as  safe 
practice  to  jjrotect  or  cap  a  pulp  that  has  not 
caused  pain  lasting  some  hours,  and  is  not 
exposed  when  all  the  carious  dentine  has  been 
removed.  It  is  always  necessary  to  make  a 
careful  examination  of  the  dentine  covering 
the  pulp  in  deej)  cavities,  to  be  sure  that  an 
exposure  does  not  exist ;  this  should  be  done 
with  a  magnifying  lens  where  it  is  possible. 
A  fine  pointed  explorer  or  broach  may  be  care- 
fully passed  over  the  area  where  the  pulp  would 
seem  to  be  nearest.  Care  should  be  taken  not 
to  allow  the  fine  point  to  penetrate,  as  un- 
necessary pain  would  then  be  caused.  Pressure 
should  not  be  directed  towards  the  pulp ;  the 
point  should  rather  be  drawn  cro^^'nwards. 
The  most  likely  point  of  exj)osure  is  at  one  of 
the  horns  of  the  i^ulp ;  in  teeth  that  are  angular 
in  form  with  long  cusps  the  horns  of  the  pulp 
run  almost  to  the  enamel. 

Factors  that  Influence  the  Location  of  the 
Pulp.- — There  are  manj^  factors  that  may 
influence  the  location  of  the  pulp.  Any  irrita- 
tion that  is  not  sufficient  to  destroy  living 
tissue  is  a  stimulant.     All  the  slight  irritations 


451 


452 


that  occur  to  the  pulps  of  teeth  tend  to  make 
them  throw  out  secondary  dentine  to  protect 
themselv-es.  The  chief  irritant  or  stimulant  to 
the  dental  pulp  is  change  of  temperature.  The 
pulps  of  old  people  have  sometimes  receded  to 
the  level  of  the  neck  of  the  tooth,  while  in  all 
cases  recession  goes  on  as  years  advance. 
Teeth  that  are  worn  away  have  their  pulps 
receded ;  in  fact,  the  horns  of  the  pulp  are 
usually  obliterated  in  such  teeth.  The  pulps 
of  teeth  of  "  mouth-breathers "  are  usually 
more  receded  than  others.  Large  metal  fillings  ; 
cavities  that  have  not  developed  rapidly  enough 
to  cause  an  exposure  or  too  much  irritation ; 
erosion  and  pyorrhoea  alveolaris ;  salt,  acid,  and 
sugar,  applied  to  the  dentine  of  a  tooth,  all 
cause  recession.  If  these  influences  on  the 
size  and  position  of  the  pulp,  and  an  exact 
knowledge  of  the  thickness  of  the  tissues  of 
the  normal  tooth,  are  borne  in  mind,  there 
should  rarely  be  any  doubt  as  to  the  location 
of  the  horns. 

Temporary  Treatment  of  Exposures  from 
Dental  Caries. — If  in  the  case  of  the  young, 
tlie  weak,  or  very  old,  the  removal  of  all  the 
carious  dentine  would  expose  a  pulp  that  had 
not  previously  caused  pain,  and  if,  for  good 
reasons,  a  temporary  operation  is  desirable, 
all  of  the  carious  tissue — which  means  soft  and 
discoloured  tissue — need  not  be  removed.  It 
is  desirable  that  large  spoon-shaped  excavators 
should  be  used  to  remove  carious  dentine  from 
cavities  in  which  there  is  any  likelihood  of 
exposing  the  pulp.  The  instrument  may  be  cut 
into  the  tissue  close  to  the  enamel,  thus  avoiding 
pressure  upon  the  pulp,  and  a  pulling  force 
applied  to  the  instrument  rather  than  a  cutting 
one ;  with  a  little  care  and  observation  the  de- 
calcified dentine  may  be  removed  from  deep 
cavities  without  pain.  Wlien  all  the  decalcified 
dentine  has  been  removed  that  is  possible 
without  an  exposure,  there  are  t-\\o  courses  of 
practice  open  to  the  operator.  In  either  case 
it  is  necessary  to  sterilize  the  remaining  tissue, 
but  this  cannot  be  done  immediately;  he  may 
apply  a  disinfectant  and  seal  the  cavity  for 
a  few  days,  or  he  may  apply  a  disinfectant 
mixed  with  some  solid  substance  and  insert 
the  filling  at  once.  Since  the  operations  under 
consideration  are  looked  upon  as  temporary, 
the  method  of  mixing  the  disinfectant  with  a 
non-irritating  solid  is  the  most  satisfactory.  It 
must  be  borne  in  mind  that  tlie  main  hope  in 
these  cases  is  for  the  pulp  to  die  painlessly 
and  not  afterwards  become  infected  with 
pyogenic  organisms,  or  that  it  may  remain  in 
a  quiescent  condition  until  a  more  convenient 
season.  It  is  believed  by  Black  (2)  and  others, 
that  if  the  ptomaines  remaining  in  the  sterilized 
tissue  are  not  sufficiently  irritating  to  destroy 
the  pulp,  the  disinfectant  is.     The  disinfectant 


used  in  such  cases  must  be  as  non-irritating 
and  as  permanent  as  possible. 

Shalloiv  Cavities. — Shallow  and  saucer-shaped 
cavities,  or  those  in  small  teeth,  are  best 
managed  by  disinfecting,  and  filling  at  a  subse- 
quent sitting,  because  there  is  not  room  for 
a  layer  of  a  disinfecting  material  and  the 
filling.  A  layer  of  oxy-phosphate  or  oxy- 
sulphate  of  zinc  should  be  used  as  a  protection 
in  any  case.  Some  operators  cover  the  part 
of  the  cavity  next  to  the  pulp  with  a  varnish, 
such  as  benzo-balsam,  sandarac,  copal,  or 
chloro-iiercha,  and  then  apj)ly  the  filling ;  this 
method  is  only  advisable  after  disinfecting  for 
several  hours.  If  the  cavity  is  deep  and  the 
immediate  operation  is  decided  upon,  there  is 
no  method  that  gives  better  results  than  mixing 
oil  of  cloves  with  oxide  of  zinc  or  \\ith  oxy- 
sulphate  of  zinc,  and  applying  this  to  the 
pulp  wall  with  a  round-ended  instrument,  and 
covering  with  oxy-phosphate  of  zinc. 

Teeth  not  Fully  Developed. — Deep  cavities  fre- 
quently occur  before  the  apex  of  the  tooth  is 
normally  closed ;  in  such  cases  it  is  very  desir- 
able to  keep  the  pulp  alive  until  calcification  is 
completed.  If  the  pulp  is  removed  from  an 
incompletely  developed  tooth,  the  canal  is 
larger  at  tlie  apex  than  it  is  at  a  point  nearer 
the  crown,  and  as  a  consequence  cannot  be 
j)erfectly  filled  with  a  solid  substance.  Besides 
this,  it  is  difficult  to  devitalize  and  remove  the 
pulp,  and  the  canal  cannot  be  perfectly  dried 
at  the  end.  The  chances  for  permanency  are 
very  remote ;  every  possible  effort  should  there- 
fore be  made  to  keep  the  pulps  of  the  young 
alive.     (See  Chapter  XXVIII.) 

First  molars  are  often  so  carious  in  children 
less  than  ten  years  of  age  that  if  all  the  de- 
calcified dentine  were  removed  the  pulp  would 
be  exposed.  In  tlie  great  majority  of  such 
cases  it  is  good  practice  to  remove  all  the  carious 
dentine  possible  -v^ithout  exposing  the  pulp, 
cover  the  pulp  wall  with  a  paste  of  oil  of  cloves 
and  oxide  of  zinc,  and  fill  the  remainder  of  the 
cavity  with  oxy-phosphate  of  zinc.  After  the 
time  for  the  full  calcification  of  the  root  is 
passed,  it  is  well  to  open  the  cavity  and  remove 
all  the  filling  and  anyr  emaining  carious 
material,  and  if  the  pulp  is  clearly  exposed, 
devitalize  it  and  insert  a  permanent  filling ;  if 
there  is  no  exposure,  oxy-sulphate  of  zinc 
should  be  placed  next  to  the  pulp,  and  over 
this  a  j^ermanent  filling.  The  same  jjractice 
may  be  followed  in  the  anterior  teeth  of  the 
young.  Many  deep  cavities  in  the  young  are 
so  sensitive  that  it  is  impossible  to  excavate 
them  properly  even  though  the  pulp  is  not 
exposed.  The  pulp  in  these  cases  may  be 
capped  with  oxide  of  zinc  and  oil  of  cloves,  and 
the  cavity  filled  with  oxy-phosphate  of  zinc 
for  a  few  months  or  a  year,  after  which  the 


453 


cement  should  be  removed  and  a  permanent 
filling  inserted.  During  the  time  the  test  fill- 
ing is  in  place,  the  pulp  will  have  been  stimu- 
lated to  throw  out  secondary  dentine  to  protect 
itself ;  the  decalcified  dentine  can  then  be  re- 
moved with  much  less  pain.  If  hypersensitive 
ca\'ities  are  filled  with  oxy-sulphate  of  zinc 
mixed  with  thymol  crystals,  and  this  is  allowed 
to  remain  in  place  for  a  few  ^\■eeks  or  months, 
the  carious  tissue  can  then  be  removed  ^\■ith 
less  pain.  Such  temporary  filling  may  be 
covered  with  oxy-phosphate  if  the  cavity  is 
large  enough  and  there  is  any  danger  of  dis- 
lodgement  of  tlie  filling. 

Discoloured  Dentine  Covering  the  Pulp. — If 
a  permanent  operation  is  intended  it  is  not 
good  practice  to  leave  any  soft  tissue  in  the 
cavity,  even  if  its  removal  would  expose  the 
pulp.  Some  authorities  go  so  far  as  to  say 
that  no  discoloured  dentine  should  be  left  in 
a  cavity.  The  tendency  at  the  present  time 
is  to  be  more  thorough  in  removing  carious 
material  than  in  the  past.  Many  of  the  older 
writers  on  this  subject  advanced  peculiar 
theories  to  support  their  views ;  some  went  so 
far  as  to  say  that  decalcified  dentine  would  be 
recalcified  inider  a  capping  of  zinc  cUoride.  No 
such  views  are  held  to-day,  but  many  continue 
to  cap  exposed  pulps  ^^-ith  zinc  chloride,  believ- 
ing that  the  irritation  of  the  drug  stimulates  the 
pulp  to  throw  out  calcium  salts  to  cover  the 
exposure.  The  success  of  the  practice,  if  it 
ever  had  any,  more  likely  depended  on  the 
disinfecting  jDroperties  of  the  zinc  chloride, 
which  retained  such  capped  jnilps  in  an  aseptic 
condition  for  a  long  time,  even  though  they 
were  dead,  than  on  recalcification  of  the  dentine. 

The  practice  of  removing  all  discoloured 
dentine  covering  a  pulp  is  equally  unwise, 
besides  being  distressing  to  the  patient.  Every 
observer  of  the  progress  of  caries  in  teetli  has 
noticed  streaks  of  discoloration,  extending  from 
a  superficial  attack  of  caries,  which  it  would  ho 
very  un\\ise  to  cut  out.  It  must  be  borne  in 
mind,  however,  that  such  discoloured  tissue 
has  been  influenced  by  the  carious  process — 
the  part  near  the  surface  much  more  than  that 
deeply  placed.  There  is  a  wide  range  between 
decalcified  tissue  that  is  compressible  when 
removed,  and  the  hard  discoloured  tissue  of  the 
penetrating  variety  just  mentioned.  It  is  safe 
practice  to  leave  discoloured  dentine  covering 
a  pulp,  when  it  is  hard  enough  to  give  a  distinct 
clink  or  ring  to  the  instrument  as  it  is  cut. 
Such  tissue  is  undoubtedly  infected,  and  con- 
tains waste  products  of  bacteria,  \\hich  may 
be  irritating  to  the  pulp.  The  bacteria  should 
be  destroyed,  and  the  ptomaines  neutralized. 
The  bacteria  may  be  destroyed  by  placing  a 
paste  of  creosote  or  oil  of  cloves  and  oxide  of 
zinc  over  the  tissue  before  inserting  the  per- 


manent filling.  Until  more  is  known  of  the 
chemistry  of  the  ptomaines  in  such  tissue  little 
else  can  be  done. 

Intermediate  Fillings.  —  There  is  a  growing 
tendency  among  careful  operators  to  place  some 
non-metallic  or  plastic  .substance  betA\een  the 
vital  tissue  of  the  tooth  and  a  metallic  filling. 
Not  a  few  ojDerators  have  followed  the  practice 
of  placing  oxy-phosphate  or  gutta-percha  be- 
tween amalgam  or  gold  fillings  and  the  tooth 
tissues.  One  of  the  important  advantages  of 
the  gold  or  porcelain  inlay  is  that  the  inter- 
mediate cementing  substance  does  not  conduct 
heat  and  cold  as  rapidly  as  the  metal,  and  thus 
protects  the  pulp  from  shock ;  besides  the  safe- 
guard against  changes  of  temperature,  it  pro- 
tects the  tooth  pulp  from  a  certain  effect  of 
irritation  that  all  metals  have  on  living  tooth- 
structure.  Every  operator  has  noticed  that 
some  teeth  are  not  comfortable  under  metal 
fillings  for  months  after  they  are  inserted, 
while  in  others  there  is  little  or  no  discomfort ; 
others,  again,  are  never  comfortable  while  a 
metal  filling  is  in  contact  with  the  dentine. 
The  WTiter  has  more  than  once  set  up  a  violent 
pain  by  jalacing  amalgam  on  living  dentine, 
which  Mas  not  relieved  until  every  particle  of 
the  amalgam  was  removed  and  a  soothing 
dressing  inserted.  It  is  good  practice  to  place 
some  non-conducting  substance  betAveen  every 
large  metal  filling  and  the  dentine.  This 
cannot  be  done  with  large  gold  fillings  in  the 
anterior  teeth,  but  fortunately  such  fillings  are 
not  now  necessary. 

Accidental  Exposures. — The  rule  generally  laid 
down  is  to  devitalize  an  exposed  pulj).  This 
rule,  however,  admits  of  a  few  exceptions.  An 
exposure  by  caries  is  hopeless.  An  exposure  by  a 
clean  instrument  cutting  sound  dentine,  which 
does  not  destroy  more  than  a  square  micro-milli- 
metre of  the  membra na  eboris  in  a  young  patient, 
may  be  looked  upon  as  a  favourable  case  for 
capping.  If  the  instniment  has  wounded  the 
pulp  so  as  to  cause  haemorrhage,  the  insertion 
of  a  capping  covered  with  a  permanent  filling 
is  courting  trouble.  If  the  tooth  is  fully 
developed  the  removal  of  such  a  pulp  is  impera- 
tive. It  might,  if  capped,  remain  comfortable 
for  years,  but  the  tooth  would  turn  dark  and 
would  be  less  likely  to  give  as  long  service  as 
if  the  pulp  liad  been  removed  at  once.  Acci- 
dental exposures  from  clean  instruments  in 
teeth  not  fully  dev^eloped  should  be  capped ; 
if  perfect  dryness  and  surgical  cleanliness 
cannot  be  secured,  results  are  proportionately 
less  likely  to   be  satisfactory. 

The  exposure  should  be  dried  by  means  of 
absolute  alcohol  and  warm  air;  and  an  aseptic, 
non-irritating,  easily  adapted  substance  should 
be  applied  to  the  exposed  surface ;  the  most 
suitable    are    the    varnishes,    such    as    benzo- 


454 


balsam,  sandarac,  or  copal;  or  gutta-percha 
dissolved  in  oil  of  cajuput.  If  the  exposure  is 
clean  when  made  there  is  no  need  to  ajDply 
strong  disinfectants  or  caustics.  The  varnish 
sliould  be  covered  with  a  layer  of  oxy-sulphate 
of  zinc  if  there  is  room ;  if  not,  the  cavity 
should  be  filled  with  oxy-phosphate  of  zinc  alone. 
Accidental  exposures  are  so  rare  %vith  careful 
operators  that  they  would  not  occur  more  than 
once  or  twice  a  year,  and  in  fully  ninety  per 
cent  of  them  the  pulj)  ought  to  be  immediately 
devitalized.  This  leaves  the  number  to  be 
capped  very  small. 

Fractures  of  the  Teeth. — -Fractures  of  the  teeth 
that  immediately  or  subsequently  involve  the 
pulp  are  not  infrequent.  They  usually  occur 
in  childhood  or  young  adult  life ;  they  are  more 
frequent  among  boys  than  girls,  because  boys 
play  more  hazardous  games  than  guls  and  are 
generally  more  careless  of  their  jiersonal  safety. 
The  upper  anterior  teeth  are  more  often  in- 
volved than  any  others;  children  often  fall,  or 
have  missiles  thrown  at  them,  which  fracture 
one  or  more  of  their  upper  incisors.  The 
fracture  may  not  expose  the  pulp,  but  the  shock 
is  often  sufficient  to  cause  it  to  die  subse- 
quently ;  in  some  cases  the  pulp  dies  from 
irritation  of  the  exposed  dentine. 

If  the  pulp  is  not  exposed  by  fracture,  the 
exposed  dentine  should  be  covered  %\ith  oxy- 
phosphate  of  zinc,  which  should  remain  until 
there  is  an  assurance  that  the  pulp  is  not  going 
to  die  from  shock  or  irritation  of  the  dentine. 
If  the  pulp  has  been  but  very  slightly  exposed 
in  a  tooth  not  fully  developed,  an  attempt 
should  be  made  to  retain  the  pulp  alive  until 
develoi^ment  is  completed.  If  there  has  been 
much  j)ain,  or  protrusion  of  the  jiulp  through 
the  exposure,  or  if  more  than  a  few  hours  have 
elapsed  since  the  accident,  there  is  little  hope 
of  success.  Even  slight  exposures  in  mature 
teeth  call  for  devitalization,  and  all  large 
exposures  demand  it. 

Technique. — Freshly  exposed  dentine  be- 
comes exceedingly  sensitive  in  a  few  hours 
if  the  fluids  of  the  mouth  are  in  contact  with  it. 
This  hypersensitive  condition  may  be  reduced  to 
a  normal  state  by  dryness.  The  rubber  should 
be  adjusted,  and  the  dentine  dried  with  warm 
air.  Applications  of  oil  of  cloves  heli^  to 
protect  the  dentine  from  stimulation  by  the 
air.  Phenol  cauterizes  the  dentinal  fibrils 
and  protects  them  from  irritation.  When  the 
exposed  dentine  has  been  thus  protected  and 
dried  with  alcohol,  thinly  mixed  oxy-phosi)hate 
will  usually  adhere  to  a  fractured  surface  if  no 
contour  of  the  cement  is  attempted.  If  space 
permits,  the  cement  may  be  pressed  into  place 
with  the  forefinger.  If  an  exposure  is  to  be 
treated,  the  method  described  under  accidental 
exposures  may  be  followed,  except  that  com- 


plete dLsinfection  is  necessary,  which  may  take 
twenty-four  hours. 

DEVITALIZATION  OF  THE   DENTAL  PULP 

As  soon  as  it  was  discovered  that  many 
pains  m  and  about  the  teeth  were  caused  by  the 
pulp,  attempits  were  made  to  destroy  its  vitality. 
The  early  methods  seem  to  us  barbarous,  but 
even  in  present  methods  there  is  great  room  for 
improvement ;  they  do  not  cope  satisfactorily 
with  pulps  that  have  been  subject  for  a  long 
time  to  i^aroxysms  of  pain  from  slight  irrita- 
tions. All  the  earlier  methods  were  surgical, 
and  had  been  j)ractised  for  many  years  before 
the  discovery  of  the  action  of  arsenic  on  the 
pulp  by  Spooner,  a  dentist  practismg  in  Mon- 
treal. He  found  that  the  destructive  action 
rarely  if  ever  passed  beyond  the  apex  of  the 
root.  This  was  one  of  the  greatest  discoveries 
ever  made  in  dentistry.  It  has  made  possible 
the  restoration  to  usefulness  of  millions  of 
teeth  that  would  otherwise  have  been  lost,  and 
has  relieved  more  pain  than  many  general 
anaesthetics.  The  next  advance  in  the  method 
of  devitalization  of  the  pulp  was  the  discovery 
of  pressure  anaesthesia  by  Funk  of  Chicago. 

The  pulp  may  be  devitalized  by  or  with  the 
aid  of 

(a)  Surgery, 

(b)  Poisons, 

(c)  Anaesthetics. 

Surgical  methods  of  devitalizing  the  dental 
pulp  have  dropped  into  disuse  since  the  intro- 
duction of  arsenic  and  need  not  be  further 
•considered. 

Many  poisons  have  been  used  for  the  purpose 
of  devitalizing  the  dental  pulp,  but  none  have 
proved  as  satisfactory  as  arsenic.  Though 
arsenic  has  many  drawbacks  it  stands  to-day 
as  the  most  universally  satisfactory  method. 
Cocaine  anaesthesia  stands  easily  in  the  second 
place.  Among  the  objectionable  features  of 
arsenic  as  a  devitalizing  agent  are  its  irritatmg 
properties,  its  failure  to  act  upon  mflamed 
tissue,  the  possibility  of  destroying  more  tissue 
than  desired,  its  toxic  or  destructive  action  on 
the  periodontal  membrane,  its  frequent  failure 
to  devitalize  completely  the  whole  of  the  pulp, 
and  the  long  time  required  for  its  action.  Drugs 
that  devitalize  tissue  by  their  cauterizing 
properties  are  too  slow  in  action  and  mostly 
too  irritatmg  to  be  of  much  value  ;  they  do  not 
penetrate — a  property  so  essential  in  devital- 
izing tissue  some  distance  from  the  pomt  of 
application.  Among  such  drugs  are  caustic 
potash,  sulphuric  acid,  hydrochloric  acid,  nitric 
acid,  chromic  acid,  zmc  chloride,  nitrate  of 
silver,  and  phenol ;  of  these  phenol  is  the  least 
irritating,    while    the    strong    acids    are    more 


455 


destructive.  These  drugs  are  only  used  where 
there  is  danger  of  too  much  destruction  if 
arsenic  is  used,  or  where  cocame  wiU  not  act. 
They  have  been  highly  recommended  for  the 
destruction  of  the  j)ulps  of  deciduous  teeth, 
but  hke  many  another  recommendation  handed 
down  from  text-book  to  text-book,  they  are  of 
little  value.  If  the  pulp  of  a  deciduous  tooth 
is  to  be  devitalized,  arsenic  is  the  most  satis- 
factory ;  there  is  no  danger  m  using  arsenic, 
where  it  is  indicated,  in  deciduous  teeth.  The 
only  requu'cment  of  the  operator  to  use  arsenic 
safely  in  deciduous  teeth  is  knowledge  of  dental 
anatomy  and  histology  and  the  action  of  the 
drug. 

This  leads  to  a  discussion  of  the  action  of 
arsenic  when  applied  to  living  tissue.  The 
reader  need  not  be  particularly  concerned  with 
whether  arsenic  devitalizes  the  pulp  by  conges- 
tion or  strangulation.  It  has  been  held  in  many 
long  and  cleverly  ^^Titten  articles  that  arsenic 
caused  the  death  of  the  pulp  by  creating  an 
irritation  that  stopped  or  hindered  the  circula- 
tion of  the  blood  in  the  veins.  It  has  been  as 
vehemently  held  that  arsenic  causes  pulps  to 
die  by  irritating  the  tissues  until  so  much  blood 
is  forced  into  the  j'ulp-cavity  through  the  fine 
opening  at  the  apex  that  the  return  circulation 
is  cut  off  and  the  pulp  is  thus  strangulated. 
For  further  discussion  on  this  subject  the 
reader  is  referred  to  works  on  therapeutics. 

The  power  of  arsenic  to  devitalize  a  pulp 
depends  upon — 

(1)  the  quantity  and  purity  of  the  drug; 

(2)  the  vitalitj'  of   the  tissue  to  which  it  is 

applied ; 

(3)  the  length  of  time  it  remains  in  contact 

with  the  vital  tissues  ; 

(4)  the  physiological  condition  of  the  tissues 

to  be  devitalized. 

Each  of  these  factors  must  be  considered  in 
every  application  of  arsenic.  Success  or  failure 
depends  more  often  upon  the  pathological 
state  of  the  tissue  of  the  pulp  than  anything 
else.  The  variations  in  the  action  of  arsenic 
are  so  great  that  ^'^  of  a  grain,  if  applied 
just  beneath  the  enamel  m  a  normal  first 
molar,  may  devitalize  the  pulp  in  twenty-four 
hours,  while  the  same  quantity  may  not 
devitalize  the  pulp  of  another  tooth  in  the 
same  mouth,  even  though  it  be  applied  to  the 
exposed  pulp  and  left  in  position  for  three 
months.  It  is  often  sagely  said,  if  a  pulp  is 
inflamed  do  not  at  once  apply  arsenic ,  but 
reduce  the  inflammation  and  then  make  the 
application.  The  first  difficulty  is  to  make  the 
diagnosis  and  the  next  is  to  reduce  the  in- 
flammation. Every  pulp  that  has  caused  pain 
is  not  inflamed,  and  every  inflamed  pulp  does 
not  cause  jjain,  and   if  the  inflammation  has 


reached  the  stage  of  passive  congestion  neither 
time  nor  drugs  will  reduce  it.  Sometimes  a 
free  haemorrhage  will  cause  the  tissues  to  absorb 
the  arsenic  (or  an  anaesthetic),  but  there  are 
many  pulps — unfortunately  they  are  the  ones 
upon  which  drugs  have  the  least  effect — that 
will  not  bleed  freely,  and  are  too  sensitive 
to  allow  of  haemorrhage  being  promoted.    Since 

,  the  action  of  arsenic  on  the  pulp  is  so  variable 
and  depends  upon  so  many  factors,  no  definite 
rule  can  be  laid  down  for  the  quantity  to  be 
used  or  the  time  it  should  be  left  in  position. 
If  the  application  is  made  directly  to  a  normal 
pulp  accidentally  exposed  in  a  young  or  middle- 
aged  patient,  ^hu  oi  a  grain  will  devitalize  it 
in  twenty-four  hours,  while  .},j  of  a  grain  may  be 
applied  to  the  dentine  of  a  tooth  with  a  pulp 
that  has  been  hypersensitive  to  changes  of 
temperature  for  months  in  the  mouth  of  an 
old  patient,  and  be  left  for  weeks  with  safety. 
Only  general  rules  can  be  laid  doT\ii  for  quantity 
and  time  :  yijj  to  tt^j  of  a  grain,  for  twenty-four 
hours  in  deciduous  and  immature  teeth,  up 
to  two  weeks  in  the  aged  and  in  teeth  with 
inflamed  or  partially  dead  pulps. 

Formes  in  which  Arsenic  is  used. — Arsenic  as 
used  for  devitalization  of  the  dental  pulp  is  a  fine 
white  powder,  -tthich  is  sometimes  adulterated 
with  chalk.  The  powder  may  be  mixed  with 
antiseptic  anaesthetic  liquids,  such  as  oil  of 
cloves  or  creosote,  until  a  paste  is  made ;  a 
little  of  this  may  be  taken  on  a  small  round- 
ended  mstrument  and  placed  upon  the  desired 
spot  in  the  cavity  of  the  tooth  to  be  treated. 
Some  operators  prefer  to  mix  the  jjowder  and 
liquid  for  each  application,  while  others  mix 
enough  at  once  to  last  for  years ;  it  is  doubtful 
whether  arsenic  retains  its  full  devitalizing 
power   if    mixed    for   a    long   time.     A  smaU 

[  pledget  of  cotton-wool  may  be  moistened  with 
creosote,  and  then  touched  with  the  arsenic 
powder,  and  carried  to  the  cavity  and  sealed. 

Pastes  are  made  of  arsenic,  creosote,  oil  of 
cloves,  and  thymol ;  instead  of  the  creosote 
or  cloves,  glycerine  or  lanolm  may  be  used, 
because  they  are  solvents  of  arsenic.  The 
following  is  a  useful  formula  for  a  paste — 

Arsenii  Trioxidi       .       .  5  J- 

Cocainae  Hydrochloridi  gr.  x. 

Thymol       .       .       .       .  gr.  v. 
M.  Fiat  unguentum. 

The  objection  to  all  forms  of  pastes  is  the 
liability  of  their  being  squeezed  out  of  the 
cavity  in  attemjDts  at  sealing.  For  several 
years  arsenic  pastes  were  used  in  the  Royal 
College  of  Dental  Surgeons  (Toronto),  and  it 
was  no  inicommon  thing  to  have  several  cases 
of  arsenical  poisoning  for  treatment  every  week. 
Since  1897  arsenical  fibre  has  been  used,  and 


456 


cases  of  poisoning  are  so  infrequent  that  many 
students  graduate  without  having  seen  one. 
Arsenic  fibre  when  rolled  up  the  size  of  a  pin's 
head  wiU  contain  sufficient  arsenic  to  devitalize 
a  pulp.  For  general  use  the  fibre  is  the  most 
satisfactory ;  it  is  convenient  to  handle,  easy 
to  seal  in  the  cavity,  does  not  tend  to  leak  out 
of  the  cavity  when  being  sealed,  and  is  easily 
removed.  The  fibre  should  be  sufficiently  dry 
to  prevent  liquid  being  exjjressed  from  it  in 
the  act  of  sealuig.  It  is  made  by  workmg 
arsenic  paste  into  a  short-fibred  cotton. 

Methods  of  Applying  and  Sealing  in  Arsenic. 
The  method  of  application  and  the  means  of 
sealing  depend  largely  upon  the  pathological 
state  of  the  pulp  as  gathered  from  the  history 
of  the  case,  and  the  presence  or  absence  of  a 
cavity  and  its  size  and  position. 

Carious  Cavities  m  teeth  approaching  or 
reachmg  the  pulp  are  the  chief  reason  for  its 
devitalization.  Cavities  that  are  so  deep  as  to 
endanger  the  vitality  of  the  jJulp  are  usually 
large  enough  to  make  the  problem  of  application 
and  sealing  a  simijle  one,  but  in  cases  where 
a  great  deal  of  the  tissue  of  the  tooth  has  been 
lost  and  the  gum  tissue  has  encroached  upon 
the  cavity,  as  is  frequently  found  in  the  disto- 
buccal  surface  of  the  third  lower  molar,  the 
problem  of  apfjlication  and  sealmg  is  a  difficult 
one.  It  is  often  difficult  on  the  labial  surface 
of  anterior  teeth,  and  in  excessive  caries  com- 
bined witli  fracture  in  jjremolars.  In  most 
cases  the  application  of  arsenic  is  best  made 
to  the  dentine  in  the  cavity ;  but  if  the  cavity 
is  so  situated  that  the  application  cannot 
be  made  without  the  possibility  of  pressure 
on  the  pulp,  or  leakage  of  the  arsenic,  it  is 
much  wiser  to  drill  a  small  hole  through  the 
enamel  at  a  convenient  spot,  and  pack  the 
arsenic  fibre  in  this,  and  place  a  dressing  of 
oil  of  cloves  and  phenol  in  the  cavity  A\here 
the  pulp  irritation  occurred ;  this  method  will 
be  found  advisable  in  distal  cavities  of  second 
molars,  and  sometimes  in  the  first  and  third 
molars.  Any  j)re-existing  pain  will  soon  sub- 
side, and  hi  three  or  four  days  the  cavity  may 
be  fully  excavated,  and  if  necessary  an  applica- 
tion made  directly  to  the  pulp,  which  may  need 
to  be  left  in  position  for  days.  If  a  pulp  has 
been  giving  pain,  it  is  not  wise  to  make  the 
application  directly  to  an  exposure  if  it  exists, 
nor  is  it  ■v\ise  to  attempt  to  make  an  exposure, 
unless  the  operator  suspects  an  ulceration  or 
abscess  of  the  coronal  portion  of  the  pulp.  If, 
however,  it  seems  to  be  fully  alive  and  is  ex- 
posed, or  if  it  has  been  exposed  surgically  and 
is  bleeding  freely,  the  application  should  then 
be  made  directly  to  the  exposure,  otherwise 
the  arsenic  is  better  applied  to  the  dentine, 
and  if  possible  an  anodyne  applied  to  the  pulp, 
or  as  near  as  can  be  to  it. 


Incisor  teeth,  especially  lowers,  do  not  give 
much  room  for  application  and  sealing ;  a  very 
small  quantity  of  arsenic  should  be  used,  and 
if  there  is  room,  this  should  be  covered  with  a 
small  piece  of  cotton-wool  moistened  with  oil 
of  cloves,  and  the  whole  covered  with  cement. 
If  the  overhanging  enamel  of  the  cavity  is  not 
broken  away  any  more  than  is  necessary  to 
gain  access  to  the  cavity,  it  will  assist  greatly 
in  retaining  the  dressing.  The  chief  cause  of 
pain  m  devitalization  of  a  pulp  \\'ith  arsenic  is 
pressure  on  the  pulp,  or  the  application  to 
semi-vital  or  infected  tissue  when  there  is  not 
an  exposure  of  fuUy  vital  tissue.  Wlien  applica- 
tions are  made  directly  to  an  exposure,  the 
effort  to  seal  effectively  often  results  in  pres- 
sure, while  if  the  application  is  made  to  the 
dentine  and  an  anodyne  applied  to  the  pulp, 
undue  pressure  is  not  so  likely  to  be  made. 
Leakage  of  arsenic  most  frequently  occurs  at 
the  time  of  application.  This  is  especially  true 
in  approximo-occlusal  cavities ;  the  gingival 
wall  of  the  cavity  is  often  not  sufficiently  dry 
to  ensure  adhesion  of  the  sealing  material, 
and  as  it  must  be  pressed  into  place  from  the 
occlusal  opening  after  the  arsenic  has  been 
placed,  there  is  every  chance  of  displacement, 
and  if  a  paste  is  used  it  is  almost  impossible 
to  avoid  its  being  squeezed  out  of  the  cavity. 
In  the  anterior  teeth  the  application  can  in 
most  cases  be  made  from  the  lingual  or  labial 
aspect ;  and  in  deep  cavities  a  small  portion 
of  the  sealing  material  may  be  placed  over  the 
gingival  wall  of  the  cavity,  the  application 
made  on  the  occlusal  aspect  of  this,  and  the 
remainder  of  the  sealing  applied. 

Sealing. — Almost  every  kind  of  plastic  sealing 
material  has  been  used  and  advocated  to  retain 
arsenical  applications.  Among  the  most  fa- 
voured are  osteo-plastic  cement,  gutta-percha, 
sandarac  varnish  and  cotton- wool,  chloro- 
percha  and  cotton-wool,  and  ^^■ax  and  plain 
cotton-wool ;  each  of  these  (and  others)  has  its 
advocates.  That  material  is  most  suitable 
\^hich  may  be  the  most  easily  applied  without 
pain,  and  will  the  most  securely  seal  the  appli- 
cation. Cement  takes  first  place  for  small 
cavities  and  cavities  upon  which  mastication 
might  dislodge  a  less  strong  material.  Sandarac 
and  cotton-wool  is  most  suitable  for  all  cavities 
that  have  to  withstand  little  or  no  force  of 
mastication,  and  that  are  deep  enough  to 
retain  it ;  it  is  most  easily  applied  and  attaches 
itself  most  securely  to  the  tooth's  surface.  If 
arsenic  fibre  is  to  be  sealed  with  sandarac  and 
cotton-wool,  it  is  well  to  cover  the  fibre  with 
some  substance  that  is  insoluble  in  alcohol 
(or  ether,  as  the  case  may  be),  so  that  the 
sandarac  may  not  spread  through  the  fibre 
and  prevent  it  coming  into  contact  with  the 
live  tissues.     If  glycerine  or  lanolin  is  used  in 


457 


the  fibre,  or  if  it  is  covered  with  a  few  shreds 
of  cotton-wool  dipped  in  vaseline  or  creosote, 
there  is  not  likely  to  be  any  penetration  of  the 
cotton-wool  by  the  sandarac.  Gutta-percha 
may  be  used,  but  it  does  not  usually  become 
sufficiently  plastic  at  a  moderate  temperature, 
and  requires  so  much  pressure  to  adapt  it  to 
the  cavity  wall  that  there  is  some  difficulty  in 
avoiding  pressure  on  the  pulp :  this,  however, 
may  be  overcome  by  placing  a  small  convex 
metal  or  celluloid  cap  over  the  fibre,  with  its 
edges  resting  on  hard  tissue. 

Tetth  with  Fillings. — If  a  tooth  is  filled  and 
the  pulp  needs  to  be  devitalized,  consideration 
should  be  given,  in  choosing  the  direction  of 
approach,  to  the  convenience  of  getting  access 
to  the  pulp  and  root-canals,  and  the  strength  of 
the   tooth   after   an   opening   has   been   made. 
Usually  the  nearest  approach  to  a  painful  pulp 
in  a  frUed  tooth  is  through  the  filling,  which 
can  be  removed  with  less  pain  than  is  caused 
by  cutting  through  live  dentine  ;  if  an  exposure 
exists  under  the  fiUmg  or  can  be  easily  made, 
the  pain  can  be  at  once  relieved.     If  the  pain 
is  not  severe,  and  the  fiUmg  is  not  such  as  will 
give  free  access  to  the  pulp,  it  is  better  practice 
to  cut  through  the  enamel  to  the  dentine  at  the 
most  convenient  site,  and  there  apply  the  arsenic. 
If    devitalization    is    advisable    for    any    other 
reason  than  to  relieve  immediate  pain,  and  the 
filling  is  in  good  condition,  the  only  considera- 
tion left  is  the  strength  of  the  tooth  after  a 
sufficient  opening  has  been  made  to  remove  the 
pulp.     If     good     approximal     or     approximo- 
occlusal  fillings  exist  in  the  incisors  or  canines, 
it    is   generally   advisable    to    open    the    pulp- 
chamber  from  the  Imgual  aspect.     If  premolars 
have    double    approximo-occlusal    fillings,    and 
the  pulp-chamber  is  opened  from  the  occlusal 
surface,  either  cusp  will  sooner  or  later  break 
away  ;    it    is    better    in   these    teeth    to    gain 
access  to  the  pulp  through  the  medial  filling, 
even  though  it  is  perfect.     Upper  molars  are 
best  opened  at  a  part  slightly  medial  to  the 
central  fossa,  whether  the  filling  is  a  good  one 
or  not :  there  is  room  in  the  molar  teeth  to  cut 
into  the  pulp-chamber  from  the  occlusal  surface 
without  making  the  tooth  so  weak  that  it  is 
liable    to    fracture.     Lower    molars    may    be 
opened  on  the  medio-occlusal  aspect  regardless 
of  the  filling ;  in  most  cases  of  medio-occlusal 
cavities  or  fillings  it  is  advisable  to  cut  away 
the   medio-buccal  cusp ;   this   is   especially  ad- 
visable if  the  tooth  is  tipped  lingually,  or  the 
cusp  has  been  undermined  by  caries. 

No  Cavity  or  Filling. — If  no  cavity  or  filling 
exists,  and  it  is  thought  advisable  to  remove  the 
pulp,  the  opening  should  be  made  at  the  part 
of  the  tooth's  surface  that  will  give  the  freest 
access  to  the  pulp-chamber  and  the  root- 
canals,  and  will  at  the  same  time  not  unneces- 
15* 


sarily  reduce  the  strength  of  the  tooth.     Hence 
the   anterior  teeth   should   be   opened   on   the 
lingual  surface  just  occlusal  to  the  cingulum. 
If  the  teeth  have  been  much  worn  by  attrition, 
as  sometimes  occurs  in  the  aged,  the  cutting 
edge  may  be  selected  as  the  site  of  opening  : 
this    is    especially   true    in    the    lower   incisors 
and  canines.     When  an  opening  on  the  lingual 
aspect   is   used  through   which  to   remove  the 
pulp,  much  care  must  be  taken  to  remove  all 
the  pulp  from  the  coronal  portion  of  the  tooth ; 
otherwise  discoloration  will  occur.     If  the  pulp 
is  alive  there  is  no  need  to  cut  through  live 
dentine  so  as  to  expose  tlie  pulp  before  applying 
the  arsenic ;    all  that  is  necessary  is  to  cut  a 
small  opening  through  the  enamel  with  a  drill 
and  pack  this  with  arsenic  fibre.     In  three  or 
four  days  this  may  be  removed,  and  the  dentine 
cut   away   painlessly   to   a  sufficient   depth   to 
ensure  devitalization  in  forty-eight  hours  more. 
There  are  a  few  cases  in  which  pulps  are  so 
sensitive  to  thermal  changes  that  it  is  impossible 
either  to  grind  or  drill  a  hole  sufficiently  deep 
to  retam  arsenic,  without  causing  severe  pain ; 
these  cases  are  found  in  highly  sensitive  people 
who  have  pyorrhoea,  and  in  whom  the  necks 
of  the  teeth  have  been  exposed  for  some  years. 
The  surface  of  the  neck  of  the  tooth  should  be 
wiped    dry  with  cotton-wool,  a  little  piece  of 
arsenical    fibre  placed  against  it,  a  pledget  of 
sandarac  and  cotton- wool  applied  over  the  fibre, 
and  the  whole  tied  to  the  tooth  by  three  or  four 
strands  of  floss  silk.     In  a  few  days  the  surface 
will  be  so  desensitized  that  an  opening  may  be 
made    deep    enough    to    permit    of     a    proper 
application. 

Since  arsenical  applications  nearly  always 
cause  more  or  less  irritation,  and  sometimes 
give  violent  jjain,  it  is  wise  to  warn  tlie  patient 
that  he  may  have  some  discomfort  from  the 
tooth  for  an  hour  or  so,  but  that  if  it  becomes 
violent  he  should  call  for  relief.  With  some 
experience  the  operator  will  be  able  to  foretell 
whether  much  pain  is  likely  to  occur.  In  the 
case  of  children,  or  patients  who  are  in  a  highly 
nervous  state,  it  is  well  to  tell  some  other 
member  of  the  family  of  the  possibility  of  pain. 
Removal  of  Arsenical  Applications. — It  is  well 
to  evmce  some  interest  in  each  case  under- 
taken, and  at  tlie  same  time  gain  information, 
by  asking  the  patient  if  he  has  experienced 
any  irritation  from  the  treatment.  If  some 
pain  was  felt  for  an  hour  or  two  and  nothing 
since,  excej)t,  perhaps,  that  the  tooth  may  have 
become  slightly  sensitive  to  pressure  during  the 
last  day,  the  pulp  is  dead.  If  changes  of  tem- 
perature have  ceased  to  cause  pain  it  may  be 
judged  that  the  pulp  is  dead.  If  changes  of 
temperature  were  not  noticed  for  a  few  days 
and  have  smce  returned,  and  the  tooth  is  also 
'  slightly  sensitive  to  pressure,  it  means  not  only 


458 


that  the  pulp  is  dead,  but  that  it  has  died  some 
days  previously,  and  the  quantity  of  arsenic 
has  been  sufficient  to  irritate  the  periodontal 
membrane  and  the  living  tissue  at  the  junction 
of  the  livmg  with  the  dead.  In  such  cases,  if 
the  dressmg  is  removed  and  an  exposure  made, 
there  will  be  an  almost  immediate  relief  of  the 
membrane  irritation  and  the  sensitiveness  to 
changes  of  temperature.  But  if  the  application 
has  been  in  position  only  for  a  short  time,  or  i 
was  placed  upon  partially  dead  tissue,  or  if  | 
the  pulp  tissue  was  much  inflamed,  then  irrita- 
tion from  changes  of  temperature  probably 
indicates  that  the  pulp  Ls  not  dead. 

A  tooth  that  was  exceedingly  sensitive  to 
touch  before  treatment  should  be  carefully 
handled  in  the  removal  of  the  dressing,  even 
though  the  pulp  is  known  to  be  dead ;  and  if 
there  is  doubt  about  the  condition  of  the  j)ulp, 
it  is  stin  more  important  to  use  such  care  as  \ 
will  enable  the  patient  to  say  whether  sensations 
felt  are  from  the  periodontal  membrane  or  a 
live  pulp.  Just  because  some  pain  is  felt  durmg 
the  removal  of  the  dressing  or  ui  removing  the 
carious  dentine  covering  the  pulp,  it  does  not 
follow  that  the  pulp  is  still  alive ;  the  procedure 
may  cause  variation  of  pressure  of  the  dead 
tissue  upon  the  living  irritated  tissue  at  the 
apex. 

Sandarac  and  cotton-wool  dressing  can  be 
readily  removed  with  tweezers  or  a  hoe-shaped 
excavator.  Cement  may  be  cut  away  with  I 
sharp  excavators  or  a  drill  in  the  engine ;  it  is 
well  not  to  use  the  engine  if  it  can  be  avoided. 
Gutta-percha  can  be  easily  removed  with  a  hot 
instrument,  but  the  temperature  or  pressure 
may  cause  pain  ;  it  is  important  not  to  cause 
the  slightest  pain  at  this  stage  of  the  operation,  i 
As  soon  as  the  dressing  has  been  removed,  a 
drop  or  two  of  cold  water  may  be  allowed  to 
run  mto  the  cavity,  and  if  this  causes  no  dis-  ^ 
comfort  a  full  stream  may  be  applied.  If  an  | 
exposure  exists,  a  very  fine,  smooth  broach 
should  be  gently  passed  into  the  pulp-cavity, 
and  if  no  sensation  occurs  as  the  pohit  reaches 
the  apex  there  is  a  positive  assurance  that  the 
pulp  is  dead,  and  that  if  there  is  any  pain 
afterwards  during  the  removal  of  the  pulp,  it  is 
probably  due  to  pressure  on  the  living  tissue 
at  the  apex,  or  tension  on  the  same  in  attempts 
at  removal,  or  to  jarring  an  inflamed  peri-  , 
odontal  membrane.  If  no  exposure  exists,  all 
the  carious  material  over  the  pulp  should  be 
removed  with  large  spoon-shaped  excavators ; 
it  should  be  remembered  that  pressure  over  an  j 
almost  exposed  dead  pulp,  or  a  sudden  plunge 
into  a  pulp-chamber,  will  probably  cause  pain 
and  frighten  the  patient.  The  dentine  may 
be  tested  for  sensation  with  fine  sharp  ex- 
cavators, ^^hich  hurt  a  sensitive  surface  without 
pressure  enough  being  used  to  make  them  cut. 


As  the  cavity  is  excavated  it  should  be  washed 
out  with  tepid  water,  and  if  an  exposure  is 
made  the  pulp  should  be  tested  with  a  fine 
broach  as  previously  described.  If  the  cavity 
is  large,  and  some  thickness  of  solid  dentme 
exists  between  it  and  the  pulp,  a  large  round 
burr  should  be  used  until  a  horn  of  the  pulp  is 
exposed.  If  a  small  burr  is  used  it  is  liable 
to  be  plunged  into  the  pulp-chamber  and  cause 
pam ;  moreover,  the  operator  will  not  know 
whether  it  comes  from  the  periodontal  mem- 
brane, the  j)ulp,  or  pressure  at  the  apex.  If 
the  pulj)  is  dead,  an  o23ening  should  be  made  the 
full  size  of  the  pulp-chamber ;  the  cavity  washed 
out  with  peppermmt  water  and  dried ;  and  an 
antiseptic  dressmg  applied.  If  the  pulp  has 
not  been  devitalized,  or  is  only  partially  dead, 
a  second  application  of  the  devitalizing  agent 
is  necessary ;  it  is  important  not  to  make  a 
second  application  if  it  can  be  avoided.  It  is 
thus  realized  why  so  much  care  should  be 
bestowed  upon  the  operation  of  removing  the 
dressing  and  gaining  access  to  the  pulp-chamber, 
because  it  is  so  easy  to  misjudge  the  meanmg 
of  the  symptoms. 

Every  pulp  should  be  devitalized  with  as 
little  arsenic  as  possible,  because  there  is  always 
danger  of  devitalizmg  not  only  the  pulp  and 
dentine,  but  also  tlie  cementum  and  periodontal 
membrane,  thus  leaving  a  lame  tooth  with 
a  limited  number  of  years  of  probable  service. 
If  a  second  application  of  arsenic  is  made  to 
a  pulp  or  dentine  when  the  former  is  already 
dead,  an  excessive  absorption  is  likely,  followed 
by  an  apparent  return  of  hypersensitiveness  of 
the  pulp,  and  the  permanent  maiming  of  the 
tooth  ;  an  accurate  diagnosis  of  the  condition  of 
the  pulp  is  more  essential  at  this  time  than  at  the 
time  of  the  fu-st  application.  If ,  however,  the  pulp 
is  alive  on  tlie  surface,  the  arsenic  may  be  there 
reapplied,  and  if  the  surface  tissue  is  dead  but 
sensation  is  reached  farther  up  the  pulp-cavity, 
a  small  shred  of  fibre  should  be  pushed  up  to 
the  live  tissue  with  a  fine  broach,  and  the  pulp 
covered  with  an  antiseptic  dressing  and  sealed 
so  that  no  pressure  may  come  upon  it  from 
mastication.  Some  good  authorities  give  the 
general  rule  that  arsenical  applications  should 
not  be  made  to  pulp  tissue  in  the  root-canal, 
because  of  the  danger  of  the  poisonous  efl^ect 
on  the  periodontal  membrane  or  beyond  the 
apex.  If,  however,  a  very  small  quantity  is 
used,  the  danger  is  no  greater  than  from  a  large 
quantity  m  the  pulp-chamber.  A  broach 
may  be  dipped  into  arsenic  paste,  and  pricked 
into  the  pulp  two  or  three  times  as  near  to  the 
live  tissues  as  possible.  This  will  carry  enough 
arsenic  to  complete  the  devitalization,  if  the 
tissue  has  not  been  previou.sly  inflamed. 

Management  of  the  Devitalized  Pulp. — Among 
the    best   operators   and    the    best   authorities 


459 


there  is  not  a  full  agreement  as  to  when  a  | 
pulp  should  be  removed  after  it  has  been 
devitalized  with  arsenic.  Such  a  well-knowii 
authority  as  the  late  A.  W.  Harlan  recommended 
that  no  attempt  should  be  made  to  remove 
the  pulp  at  the  time  of  the  removal  of  the  arseni- 
cal application,  but  that  instead  an  application 
of  a  saturated  solution  of  tannic  acid  in  either 
alcohol  or  glycermo  should  be  made  for  at  least 
a  week  or  ten  days.  ThLs  \\as  to  give  sufBcient 
time  for  the  dead  tissue  to  become  separated 
from  the  livmg  at  the  apex.  The  tannic  acid 
was  supposed  to  toughen  the  tissue  sufficiently 
to  allow  it  to  come  away  in  one  piece ;  and  the 
glycerine  so  to  act  upon  the  red  blood-corpuscles 
that  discoloration  of  the  tooth  did  not  occur. 
Buckley,  in  his  recent  work  on  therapeutics, 
says  in  reference  to  this  practice  :  "  Let  us 
consider  the  rationalism  of  such  treatment. 
The  pulj)  tissue  ui  all  large  canals  is  sufficiently 
tough  to  be  removed  m  its  entirety,  and  it  must 
be  disorganized  or  removed  piecemeal  in  small 
canals,  whether  it  has  been  previously  con- 
stringed  or  not.  Hence,  there  is  no  advantage 
in  using  tamiic  acid,  and  there  is  no  serious 
objection.  If  those  who  follow  this  practice 
are  observant,  they  wiU  notice  after  they 
remove  the  tannic  acid  dressing,  that  the  pulp 
tissue  is  dark  m  appearance.  They  wiU  also 
observe  that  many  teeth  thus  treated  subse- 
quently discolour.  The  cause  of  this  Is  found 
in  the  fact  that  tannic  acid  and  iron  in  any 
form  are  chemically  incompatible,  the  resultmg 
compound  being  iron  tamiate,  one  of  the  most 
msoluble  substances  known  to  chemistry.  In 
the  presence  of  moisture  a  form  of  ink  is  pro- 
duced, which  is  a  great  staining  agent  for  the 
dent  me,  and  one  that  it  is  almost  impossible  to 
remove  by  any  known  process  of  bleachmg." 

Few  operators  have  noticed  the  peculiar 
tamimg  effect  of  the  tannic  acid,  but  many  have 
recognized  the  advantage  of  not  attemptmg 
to  remove  the  pulp  for  two  or  three  weeks  after 
it  has  been  devitalized.  It  is  then  detached  | 
from  the  tissue  at  the  apex  and  comes  away 
without  pain ;  and  if  disintegration  has  occurred, 
the  apical  contents  can  be  absorbed  with  cotton- 
wool. The  pulp  may  be  kept  aseptic  during  this 
period  under  a  dressing  of  oil  of  cloves,  creosote, 
or  thymol ;  no  drug  should  be  used  that  might 
discolour  the  dentine.  Though  this  waiting 
method  has  been  recommended  by  the  highest 
authorities,  few  seem  to  follow  it.  The  general 
rule  is  to  attempt  to  remove  the  pulp  when  the 
arsenical  application  is  removed.  This  method, 
though  painful,  is  perhaps  more  suited  to  the 
anterior  teeth,  because  the  tissue  can  be  taken 
away  with  one  pull,  and,  besides,  there  is  less 
likelihood  of  discoloration ;  the  canal  can  be  at 
once  wiped  out  and  dried,  no  opportunity  being 
left    for    the    disintegration    of     red     blood- 


corpuscles.  The  waiting  method  has  a  distinct 
advantage  m  molars  and  upper  premolars.  At 
best  it  is  a  tedious  operation  to  remove  the 
pulp  from  these  teeth,  and  if  it  is  still  attached 
to  the  walls  of  the  chamber  and  the  apex,  and, 
in  addition,  pain  Is  caused  every  time  the 
broach  is  moved  in  the  canal,  the  operation  is 
distressing  to  both  the  operator  and  the  patient. 
Anaesthetics. — About  ten  years  after  the 
introduction  of  cocame,  as  a  local  anaesthetic. 
Funk  of  Chicago,  U.S.A.,  discovered  pressure 
anaesthesia.  Since  then  the  method  has  under- 
gone many  modifications,  and  a  great  variety 
of  drugs  has  been  used  ;  among  these  are  cocaine, 
eucaine,  stovaine,  novocame,  nervocidin,  and 
a  combination  of  phenol,  cocaine,  and  adrenalin. 
Funk's  original  method  is  the  most  universally 
applicable  :  Remove  the  decay  from  the  cavity 
untU  an  exposure  is  obtained.  Dissolve  a  few 
crystals  of  cocaine  in  a  drop  or  two  of  alcohol 
or  water,  and  absorb  the  solution  with  a  small 
piece  of  spunk.  Place  this  on  the  exposure. 
Take  a  piece  of  raw  ^iilcanizing  rubber  (soft 
and  sticky)  larger  than  the  cavity,  so  as  to 
occlude  the  outside  of  it.  When  this  is  in 
place,  select  as  large  an  instrument  as  wiU 
enter  the  orifice  of  the  cavity,  or  a  large  flat 
instrument,  and  gradually  brmg  pressure  to 
bear  upon  the  rubber,  keeping  in  mind  that 
success  wOl  not  come  unless  the  rubber  acts  as 
a  piston,  and  forces  the  cocaine  solution  into 
the  pulp.  Use  steady  pressure,  gradually 
increasing  it,  and  finaUy  kneading  the  rubber 
into  the  cavity.  If  the  final  kneadmg  causes 
no  pain,  the  rubber  and  spunk  should  be  re- 
moved and  the  pulp  tested  with  a  fine  broach 
for  vitality.  If  haemorrhage  occurs  at  this 
time  the  pulp  is  not  fully  desensitized,  and  a 
further  application  had  better  be  made  at  once. 
If  the  pulp  Is  fully  desensitized,  the  cavity  should 
be  freely  opened  until  access  can  be  obtained 
to  the  pulp-chamber  and  root-canals. 

Removal  of  the  Pulp  must  be  accomplished 

I  within  a  very  few  minutes,  or  sensation  wiU 
return.  The  most  satisfactory  method  of  domg 
this  is  by  means  of  cotton-fibre  wound  on  a 
fine  smooth  broach,  as  described  below,  under 
"  Removal  of  Pulps  ".  If  success  has  not  come 
after  five  or  si.x  attempts,  another  method  should 
be  tried.  Cotton-wool  saturated  with  phenol 
should  be  carried  to  the  apex  to  prevent  return 
of  sensation ;  then  a  barbed  or  hooked  broach 
may  be  tried,  or  if  this  fails,  a  fine  reaming 
broach  may  be  rotated  to  the  ape.x,  an  attempt 
being    made    to    separate    the    pulp    from    the 

}  tissue  at  the  apex.  In  all  round  or  single- 
rooted  teeth  the  fii'st  or  the  second  method  wiU 
usually  succeed. 

Excessive  Haemorrhage  may  follow  the  removal 
of  the  pulp ;  several  drops  of  blood  may  come 
away.     It    may    liave    been    noted    that    the 


460 


haemorrhage  did  not  occur  immediately  after 
the  pulp  was  removed.  Cocaine  acts  as  an 
astringent  when  first  applied,  but  a  reaction 
soon  takes  jjlace  and  the  vessels  dilate,  and  there 
is  then  excessive  haemorrhage.  As  soon  as 
the  haemorrhage  seems  to  be  stojjping  of  its 
own  accord,  the  cavitj'  should  be  washed  out 
and  dried,  a  mild  dressing  inserted,  and  the 
cavity  securely  sealed  for  a  few  days.  If 
excessive  haemorrhage  occurs  it  is  an  indication 
that  a  good  deal  of  the  drug  has  been  absorbed, 
which  may  be  sufficient  to  irritate  the  tissues 
at  the  apex  and  cause  a  soreness  of  the  tooth  last- 
ing for  several  days,  or  even  weeks.  In  such 
cases  the  canal  should  not  be  immediately 
filled,  because  there  is  then  no  opportunity 
of  removing  mechanically  the  waste  products 
of  inflammation,  which  might  go  on  to  suppura- 
tion and  permanent  laming  of  the  tooth. 

Immediate  root-filling  is  only  permissible 
after  cocaine  anaesthesia  when  the  pulp  was  not 
previously  infected,  and  there  was  not  excessive 
haemorrhage,  and  also  when  the  apex  is  small 
and  absolute  dryness  is  obtainable. 

If  the  pulp  has  an  ulcerating  surface,  or  is 
infected,  pure  phenol,  or  phenol  and  cocaine, 
should  be  used  for  pressure  anaesthesia  of  the 
pulp.  If  cocaine  alone  is  used  the  infection 
may  be  forced  through  the  apex  and  an  alveolar 
abscess  result ;  if  phenol  is  used  the  absorption 
of  the  drug  is  limited,  and  disinfection  occurs. 
Novoeaine  and  adrenalin  chloride  are  used 
together  for  local  anaesthesia  with  satisfactory 
results ;  the  adrenalin  hinders  the  dissipation 
of  the  anaesthetic  and  limits  its  action  to  the 
part  where  it  is  needed. 

In  cases  of  accidental  exposure  of  the  pulp, 
as  in  fracture,  or  by  the  excavator  or  burr  a 
few  crystals  of  cocaine  may  be  placed  upon  the 
exposure,  and  in  a  few  minutes  the  pulp  may 
be  jjainlessly  removed.  This  will  only  act 
immediately  after  the  exposure  occurs;  if 
several  hours  have  elapsed  absorption  of  the 
anaesthetic  will  not  take  place. 

Some  years  before  Funk  introduced  pressure 
anaesthesia  Manning  Burge  suggested  injecting 
a  cocaine  solution  into  the  pulp  with  a  hypo- 
dermic syringe  :  If  the  pulp-chamber  is  suffi- 
ciently open,  the  needle  is  inserted,  and  gutta- 
percha or  raw  vulcanizing  rubber  is  packed 
aroiuid  the  needle,  and  held  while  force  is  brought 
to  bear  upon  the  j)iston  of  the  syringe.  This 
method  is  very  successful  with  partially  devi- 
talized pulps  if  phenol  is  u.sed. 

High-Pressure  Anaesthesia  of  the  Dentine. 
About  1903  Myer  of  Cleveland,  U.S.A.,  intro- 
duced high  pressure  anaesthesia  of  the  dentine  : 
A  small  tapering  hole  is  drilled  througli  the 
enamel  to  the  dentine,  and  into  this  is  inserted  a 
needle  that  fits  tightly ;  and  by  means  of  a 
specially  constructed  syringe  sufficient  force  is 


applied  to  drive  a  cocaine  solution  into  the 
dentine  so  as  to  desensitize  it  and  the  pulp. 

Anaesthesia  of  the  Pulp  from  Surrounding 
Tissues. — The  dentine  and  iHilp  may  be  desen- 
sitized by  injecting  cocaine  solution  into  the 
gum  tissue  around  the  tooth.  Some  operators 
recommend  drilling  through  the  process  and 
injecting  the  solution  into  the  diploe,  so  as  to 
anaesthetize  several  teeth  at  once  if  they  are 
to  be  operated  upon. 

Occasions  for  Use  of  Pressure  Anaesthesia. 
Cocaine  anaesthesia  is  best  suited  for  single- 
rooted  teeth  with  exposed  pulps  that  are  not 
inflamed.  In  multi-rooted  teeth,  sensation 
often  returns  before  all  the  canals  are  cleared 
out.  If  any  shred  of  such  a  desensitized  pulp 
is  allowed  to  remain,  severe  pain  may  be  felt 
until  the  piece  is  either  dead  or  removed.  On 
the  other  hand,  with  arsenic  the  finest  portions 
die,  and  even  if  they  are  not  removed  immediate 
pain  does  not  occur.  Pressure  anaesthesia  of 
the  pulp  is  rarely  accomplished  without  some 
pain.  It  has  advantages  over  arsenic  in  its 
rapid  action  and  in  the  smaller  probability  of 
discoloration  of  the  tooth. 

Toxicity. — Cocaine  pressure-anaesthesia  can- 
not be  accomplished  without  some  danger  of 
local  and  general  poisoning.  It  is  almost 
impossible  to  know  what  patients  will  be 
poisoned  and  what  quantity  can  be  borne  with- 
out ill-effect ;  even  the  smallest  quantity  will 
cause  the  profoundest  effect  in  one  patient,  while 
ten  times  the  dose  will  not  affect  another  or  the 
same  patient  at  another  time ;  the  smallest 
quantity  should  be  used  that  will  produce  the 
desired  result.  Care  should  be  taken  that 
none  of  the  solution  is  allowed  to  escape  into 
the  mouth  or  be  swallowed.  Phenol  has  been 
known  to  produce  an  area  of  anaesthesia  in  the 
distribution  of  the  inferior  alveolar  nerve,  when 
squeezed  into  the  pulp  of  the  third  lower  molar. 
The  local  absorption  may  be  sufficient  to 
destroy  the  vitality  of  the  tissues  at  the  apex 
of  the  tooth,  and  result  in  a  tooth  that  may 
remain  sore  for  weeks  and  never  return  to  a 
normal  condition.  Novoeaine,  eucaine,  and 
stovaine,  are  less  toxic  than  cocaine  and  are 
more  generally  used. 

Refrigeration. — Pulps  of  teeth  may  be  desen- 
sitized by  the  application  of  such  refrigerating 
drugs  as  ether  or  ethyl  chloride.  The  tooth 
may  be  isolated  with  the  rubber-dam  and  the 
drug  apijlied  in  a  spray.  If  a  pulp  is  inflamed 
and  causing  pain,  and  is  relieved  by  cold,  there 
is  nothing  better  than  the  application  of  a  spray 
of  ether  for  a  few  minutes,  and  then  of  ethyl 
chloride  while  the  tooth  is  being  cut  into  and 
the  pulp  made  to  bleed  freely,  when  arsenic 
may  be  apj)lied  \\ith  an  assurance  that  no  more 
pain  Anil  occur.  Ethyl  cliloride  has  often  been 
used  with  good  effect  on  partially  dead   pulps 


461 


in  anterior  teeth.  The  nostrils  must  be  shielded, 
or  else  the  evaporating  ethyl  chloride  ^\  ill  pro- 
duce a  general  anaesthesia. 

General  Anaesthetics. — Highly  inflamed  pulps 
that  are  causing  acute  pain  can  only  be  satis- 
factorily treated  by  the  administration  of  a 
general  anaesthetic ;  during  its  influence  the 
pulp-chamber  is  cut  into,  and  if  f)ossible  the 
pulp  removed.  Partially  dead  and  inflamed 
pulps,  and  cases  of  pulp-stone,  may  be  similarly 
treated.  If  several  pulps  are  to  be  devitalized 
in  the  same  mouth,  they  may  be  most  expe- 
ditiously treated  under  a  general  anaesthetic. 
For  all  ordinary  cases  nitrous  oxide  anaesthesia 
is  sufficient ;  it  is  the  safest,  and  altogether  the 
most  satisfactory. 

CONDITIONS   REQUIRING    DEVITALIZATION 
OF   THE   DENTAL   PULP 

(1)  Exposure  of  the  pulp. 

(2)  Inflammation  that  is  indicated  by  pain 

or  hypersensitivity  to  changes  of  tem- 
perature. 

(3)  Hypertrophic  inflammation  of  the  pulp. 

(4)  Atrophic  inflammation  of  the  pulp. 

(5)  Recession  of  the  pulp. 

(6)  Ulceration  of  the  pulp,  and  abscess  of  the 

pulp. 

(7)  Erosion  or  abrasion. 

(8)  Pulp-stones  and  pulp-nodules. 

(9)  Pyorrhoea  alveolaris. 

(10)  Crowns  with  dowels. 

(11)  Abutments  for  bridges. 

(12)  Posts  for  large  fillings. 

Management  of  Exposed  Pulps. — Pulps  exposed 
by  caries  in  the  anterior  teeth  and  not  causing 
pain  are  best  devitalized  by  cocaine  anaesthesia, 
provided  the  cavity  is  of  such  a  form  that  pres- 
sure can  be  applied.  In  multi-rooted  teeth 
arsenic  is  usually  the  most  suitable,  but  if  there 
is  any  reason  for  haste  pressure  anaesthesia  may 
be  used  with  satisfactory  results.  Pulps  recently 
exposed  by  accident  or  by  surgery  may  be 
desensitized  by  placing  a  few  crystals  of  cocaine 
on  the  exposure  for  a  few  minutes,  and  if  suffi- 
ciently anaesthetized,  removed  at  once ;  if  not, 
a  hypodermic  needle  may  be  passed  a  short 
distance  into  the  pulp-cavity  and  a  solution 
of  cocaine  injected  ;  if  this  fails,  or  the  pulp  is 
still  sensitive,  a  broach  dipped  into  arsenical 
paste  may  be  j)ricked  into  the  surface  of  the 
pulp,  or  a  fine  shred  of  arsenical  fibre  slipped 
into  the  pulp-chamber  beside  the  pulp,  and  the 
whole  covered,  when  possible,  with  cement. 
If  a  pulp  has  been  exposed  by  accident  for  some 
hours  or  days,  and  has  been  irritated  by  changes 
of  temperature,  fluids  of  the  mouth,  and  food, 
the  tissue  usually  protrudes  from  the  cavity 
and  is  so  exceedmgly  sensitive  that  it  is  impos- 
sible to  touch  it  with  anything.     If  the  pulp  is 


accessible  at  all,  a  few  grains  of  cocaine  may  be 
placed  upon  it ;  but  the  difficulty  in  such  cases 
is  that  so  much  pain  is  caused  by  exposure  to 
air  that  it  is  necessary  to  cauterize  the  surface 
at  once  «ith  phenol  to  relieve  the  pain,  and  this 
prev^ents  the  action  of  the  cocaine.  The  phenol 
should  be  gradually  worked  into  and  around 
the  pulp  until  the  pain  stops ;  arsenic  can  then 
be  applied  in  the  pulp-cavity  beside  the  pulp. 
If  this  method  is  not  successful  a  general 
anaesthetic  may  be  administered,  and  the  pulp 
at  once  removed  if  in  an  anterior  tooth ;  and  if 
in  a  molar,  as  much  taken  out  as  possible,  and 
the  remainder  devitalized  with  arsenic.  A  high- 
pressure  syringe  may  be  used  satisfactorily  if 
there  is  good  enough  circulation  in  the  pulp 
to  carry  the  cocaine  solution.  Injections  of 
cocaine  solutions  into  the  gum  tissue  about 
the  apex  of  the  tooth  will  produce  the  desired 
result.     Refrigerating  sprays  are  too  painful. 

Management  of  Inflamed  Pulps. — As  a  general 
rule  all  painful  pulps  are  inflamed,  and  so 
are  almost  all  pulps  exposed  from  caries.  All 
pulps  that  are  exposed  should  be  devitalized 
(except  as  on  p.  452),  and  all  pulps  that  are  in- 
flamed or  have  caused  pain  for  some  hours 
should  be  devitalized.  Pulps  that  are  exposed 
from  caries,  or  are  painful  from  pressure  of  food 
or  other  substances,  may  be  relieved  by  removmg 
carious  dentine  or  the  substance  causmg  pres- 
sure. If  the  paui  is  caused  by  salt,  sugar,  or 
fermentations  in  the  cavity,  it  may  be  relieved 
by  gently  washing  out  the  cavity  with  tepid 
water  and  removing  any  loose  carious  material, 
and  applying  an  anodyne,  such  as  oil  of  cloves, 
phenol,  or  cocaine.  Relief  is  not  certahi  in  any 
of  these  cases  unless  haemorrhage  is  obtained. 
It  is  remarkable  that  sometimes  if  arsenic  is 
placed  upon  the  dentine,  the  pain,  which  has  been 
gonig  on  perhaps  for  hours  will  be  relieved  in  a 
short  while.  It  the  pain  is  not  too  severe  to  be 
borne,  an  anodyne  should  be  applied  to  the  pulp, 
and  arsenic  applied  to  the  dentine  and  sealed, 
so  that  the  patient  cannot  remove  it.  The  pain 
may  last  for  a  short  while,  but  it  usually  sub- 
sides in  an  hour  or  two.  If  the  pain  is  severe, 
attempts  should  be  made  to  relieve  it.  Appli- 
cations of  cocaine,  oil  of  cloves,  phenol,  and  other 
tried  remedies  having  failed  to  give  relief, 
pressure  anaesthesia  with  phenol  may  be  tried. 
If  this  fails,  a  spray  of  ethyl  chloride  will  gener- 
ally work  admirably ;  the  tooth  nuist  be  acces- 
sible, and  the  rubber-dam  should  be  in  position  ; 
and  it  is  well  first  to  cover  the  tooth  with  cotton- 
wool and  apply  the  spray  gently,  then  gradually 
to  remove  the  cotton- wool  until  a  full  spray  can 
be  applied  to  the  tooth.  When  the  pulp  is 
anaesthetized,  a  round  l)urr  as  large  as  will 
enter  the  pulp-chamber,  rapidly  revolving  in 
the  engine,  should  be  plunged  into  the  pulp. 
This  will  secure  a  free  haemorrhage  and  relieve 


462 


tlie  paiii,  and  ensure  a  certain  and  rapid  action 
of  arsenic,  wliicli  should  be  at  once  applied. 
General  anaesthesia  is  also  satisfactory  for  this 
operation. 

Inflamed  and  Painful  Pulps  that  are  not  exposed 
are  often  difficult  to  locate.  There  are  so  many 
causes  of  pain  in  an  unexposed  jjulp,  and  they 
are  so  obscure,  and  the  symptoms  are  so  bewilder- 
ing to  both  the  patient  and  the  dentist,  that  it  Ls 
little  wonder  they  are  so  often  undiagnosed. 
(For  the  pathology  of  the  dental  pulp  see  Chapter 
XVI,  and  for  referred  pain  see  Chapter  XXVI.) 
Pulps  that  are  actively  congested  are  hyper- 
sensitive to  cold  and  may  be  soothed  by  mild 
warmth  ;  pulps  that  are  passively  congested  are 
soothed  by  cold  and  irritated  by  warmth  or  heat. 
Pulps  that  are  hypersensitive  to  either  heat  or 
cold  are  in  a  pathological  state.  All  j)ersons' 
teeth  are  not  equally  responsive  to  changes  of 
temperature  ;  each  person  has  his  own  standard 
of  sensibility.  The  sensitivity  of  the  suspected 
tooth  must  be  gauged  by  the  action  of  the  same 
degree  of  heat  on  normal  teeth  in  the  same 
mouth. 

A  tooth  that  has  an  actively  congested 
pulp,  and  has  not  ached  violently  for  some  hours, 
need  not  be  devitalized ;  such  a  tooth  should 
be  protected  from  thermal  shocks  by  drying 
it  and  covering  it  with  a  varnish  ;  and  a  cathar- 
tic and  one-grain  doses  of  quinine,  or  small 
doses  of  aconite  or  belladonna  should  be  ad- 
ministered to  the  patient.  When  passive  con- 
gestion exists  or  pressure  from  gases,  the  pulp- 
chamber  must  be  opened,  and  if  the  pulp  is 
alive  it  must  be  devitalized.  If  no  cavity 
exists  in  the  tooth,  a  convenient  point  from 
which  to  reach  the  pulj)  is  selected,  and  a  hole 
drilled  directly  towards  the  pulp.  During  the 
drilling,  cold  water  or  a  spray  of  ether  or  ethyl 
chloride  should  be  cast  upon  the  tooth  to  reduce 
the  pain  of  drilling  and  the  shock  of  puncturing 
the  jnilp.  Here  again  general  anaesthesia  may 
be  used.  If  a  cavity  exists,  the  carious  dentine 
may  be  removed  and  an  exposure  made  vA\.\\ 
large  spoon  excavators ;  as  soon  as  this  occurs 
relief  is  obtained.  An  anodyne  and  arsenic 
may  be  applied  with  the  assurance  that  there 
will  be  no  further  pain. 

Management  of  Hypertrophied  Pulps. — An  irrita- 
tion that  is  not  sufficient  to  destroy  vitality 
is  a  stimulant.  Pulps  of  the  young  are  often 
exposed  by  caries  and  remain  so  exposed  for 
years,  gradually  increasing  in  size  until  they 
protrude  through  the  pulp-chamber  and  almost 
fill  the  cavity  in  the  tooth.  These  hypertrophies 
most  often  occur  in  first  molars.  They  have 
become  accustomed  to  their  surroundings,  and 
are  not  easily  irritated  by  chemicals,  changes 
of  temperature,  or  mechairical  irritation.  The 
patient  avoids  masticating  upon  the  affected 
tooth. 


It  is  difficult  to  differentiate  a  hyiJertropliied 
pulp  from  gum  tissue  that  has  grown  into  the 
cavity  of  the  tooth,  either  from  an  approximal 
surface  or  from  between  the  roots.  Gum 
tissue  irritated  by  lying  upon  the  sharp  edge 
of  a  cavity  bleeds  as  freely  and  is  quite  as  sensi- 
tive to  manipulation  as  a  hj-^jertrophic  pulp. 
In  both  cases  the  tissue  is  pedunculated,  and 
cocaine  crystals  may  be  slipped  under  the  flap 
to  reach  as  near  to  the  neck  as  possible.  In  a 
few  minutes  a  fine-pointed  excavator  may  be 
slipped  under  the  tissue,  and  the  position  of 
the  neck  made  out.  A  thorough  knowledge 
of  dental  anatomy  will  now  be  of  assistance. 
If  the  operator  is  satisfied  that  the  tissue  comes 
from  the  root-canal  or  the  pulp-chamber,  a  few 
strands  of  arsenic  fibre  may  he  slipped  under 
the  flajj,  and  the  cavity  sealed  with  cotton- 
wool and  sandarac  varnish.  If  he  is  not  satis- 
fied, more  cocaine  should  be  used,  and  with  a 
large  spoon-shaped  instrument  the  tissue  should 
be  cut  out  of  the  cavity.  TOien  the  haemorrhage, 
which  will  be  profuse,  has  been  controlled  by 
hot  water,  another  examination  may  be  made ; 
and  if  the  operator  is  still  not  satisfied,  the 
cavity  should  be  packed  with  phenol  and  san- 
darac vamish  for  twenty-four  hours,  when  all 
haemorrhage  will  have  ceased  and  a  diagnosis 
can  be  made.  If  the  tissue  is  pulp,  arsenic 
may  be  applied  to  the  remainder,  and  the  case 
treated  in  the  ordinary  way. 

Management  of  Atrophic  Pulps. — Owing  to 
irritation  or  diminished  circulation,  chlorosis 
of  the  dental  jiulp  sometimes  occurs.  The 
fibrous  elements  increase ;  the  tooth  does  not 
respond  to  changes  of  temperature ;  and  the 
pulp  decreases  in  size.  There  is  little  or  no 
blood,  and  no  sensation  in  certain  places,  but 
excessive  hypersensitiveness  in  others,  so  that 
the  pam  may  be  exceedingly  violent  when 
the  pulf)  is  touched  with,  a  broach.  Neither 
cocaine  nor  arsenic  has  any  effect :  there  is 
not  sufficient  circulation  to  absorb  the  drags. 
This  condition  often  occurs  under  metal  fillings 
that  have  been  placed  close  to  the  pulp  or  on 
an  exposure. 

Treatment. — The  cavity  should  be  flooded 
with  pure  phenol,  which  should  be  gradually 
worked  into  the  pulp-cavity  with  a  broach, 
and  finally  forced  in  with  soft  rubber.  No 
other  drug  is  nearly  so  satisfactory  as  phenol 
in  these  cases.  Phenol  may  be  forced  into  the 
canal  with  a  hj'podermic  syringe. 

Management  of  Receded  Pulps. — On  p.  452  are 
given  the  reasons  for  the  recession  of  the  pulp. 
There  seems  to  be  a  certain  physiological  reces- 
sion of  the  pulp,  and  if  more  than  this  occurs 
atrophy  and  death  supervene.  Pulps  that  have 
receded  because  of  the  nearness  of  a  cavity  or 
metal  filling,  or  on  account  of  exposure  of  dentine 
to  irritation,  are  prone  to  become  atrophic  and 


463 


die.  Pulps  that  have  been  exposed  may  recede 
and  live  for  years,  but  in  no  case  does  the  original 
exposure  become  covered  with  calcific  material ; 
if  the  cavity  is  opened,  a  broach  can  be  passed 
down  the  exposure,  and  though  it  may  strike 
calcific  material,  if  it  is  worked  around  an 
opening  -will  be  found.  It  would  seem  that  the 
membrana  eboris  when  once  destroyed  does 
not  reproduce  itself  laterally;  or  if  this  occurs, 
it  does  not  seem  to  have  the  power  of  depositing 
lime  salts.  If,  -when  a  filling  has  been  removed, 
there  is  evidence  of  the  pulp  having  been  at 
one  time  exposed,  pressure  anaesthesia  can  at 
once  be  applied  witli  success.  The  general 
rule  has  been  laid  do\\Ti  by  some  authorities, 
that  pulps  that  have  receded  to  within  one  or 
two  millimetres  of  the  neck  of  the  tooth  should 
be  devitalized ;  it  has  been  observed  that  in- 
fections from  pulps  that  were  much  receded 
or  atrophic  before  death,  are  especially  severe 
and  of  the  streptococcus  variety. 

Management  of  Ulceration  and  Abscess  of  the 
Pulp. — Wien  a  pulp  that  is  exposed,  or  almost 
exposed,  becomes  infected  with  pus  organisms, 
and  as  a  result  there  is  an  exudation  of  pus 
from  the  surface,  it  is  said  to  be  ulcerated ;  if 
the  infection  has  penetrated  a  layer  of  leathery 
dentine  to  reach  the  pulp,  and  pus  is  formed  in 
the  substance  of  the  pulp  tissue  around  it,  the 
condition  is  then  called  "  Abscess  of  the  Pulp  ". 
If  an  ulcerating  pulp  by  any  means  becomes 
covered,  so  tliat  the  exudate  cannot  get  away 
freely,  pain  will  supervene,  which  is  relieved 
by  cold  and  increased  by  heat ;  the  symptoms 
of  abscess  of  the  pulp  are  the  same.  The  pain 
is  of  a  deep  throbbing  character,  and  if  it  goes 
on  for  several  hours  the  tooth  becomes  tender 
to  touch.  In  fact,  if  there  have  been  several 
attacks,  the  tooth  vnll  become  tender  and  elon- 
gated almost  as  soon  as  the  pain  begins ;  in 
such  cases  all  the  pulp  tissue  in  the  crown  of 
the  tooth,  and  perhaps  for  some  distance  into 
the  root-canals,  may  be  a  dead  and  infected 
mass. 

The  treatment  is  essentially  the  same  as 
for  an  inflamed  pulp.  The  pressure  must 
first  be  relieved.  If  there  is  a  cavity,  the  carious 
material  should  be  removed,  and  the  cavity 
washed  out  \\ith  cool  water.  As  soon  as  the 
pulp-chamber  is  opened  (which  should  be  done 
with  a  great  deal  of  care  lest  pressure  cause 
excessive  pain)  pulsations  can  be  seen  in 
the  liquid  exiidate  or  blood.  Wlien  these 
pulsations  begin  tlie  patient  will  feel  extreme 
jiain,  and  it  is  well  not  to  continue  to  operate 
after  an  exposure  has  been  made,  lest  the 
patient  should  tliink  the  operator  is  causing 
the  pain.  If  an  ab-scess  exists  on  the  surface, 
the  exiidation  of  the  pus  will  be  followed  by 
blood ;  the  exudation  should  be  wiped  away, 
and    the    patient   assured   that    the  pain  will 


subside  in  a  few  minutes  and  not  return. 
Cocaine,  oil  of  cloves,  or  phenol,  may  be  placed 
in  the  cavity  for  a  few  minutes  while  waiting 
for  the  pain  to  subside.  The  cause  of  the  pain 
is  the  stretching  of  the  nerves  back  to  their 
normal  state  after  being  compressed.  It  is 
sometimes  difficult  to  know  whether  the  pus 
and  blood  are  coming  from  a  small  portion  of 
pulp  in  the  root-canal,  or  from  the  apex.  If 
there  is  any  doubt,  a  broach  should  be  passed 
up  tlie  canal,  and  if  there  is  sensation  in  tlie 
pulp<-liamber  or  not  too  far  up  the  canal,  a 
very  small  piece  of  arsenical  fibre  may  be  worked 
up  until  it  is  in  contact  with  the  live  tissues. 
If  only  a  small  portion  of  the  pulp  at  the  apex 
is  alive,  it  is  \\iser  to  jiack  the  cavity  with  phenol 
until  the  next  sitting,  and  then  try  pressure 
anaesthesia,  using  phenol.  Arsenic  may  be 
placed  on  an  ulcerating  or  abscessed  pulp  in 
which  the  pressure  has  been  relieved  and  a 
liaemorrhage  has  occurred,  with  an  assurance 
that  there  will  be  no  further  pain. 

If  there  is  no  cavity  in  the  tooth,  or  a  large 
filling  to  be  cut  througli  to  reach  tlie  pulp- 
chamber,  it  must  be  borne  in  mind  that  the  rotat- 
ing drill  will  cause  pain  from  heat,  or  the  jarring 
may  cause  pain  to  the  periodontal  membrane ; 
each  of  these  may  be  confounded  with  the  pain 
of  cutting  sensitive  dentine,  and  might  thus 
cast  .some  doubt  on  the  diagnosis.  Small  sharp 
drills  sliould  be  used. 

Management  of  Pulps  containing  Calcific  Deposits. 
Calcific  deposits  occur  in  the  pulps  of  teeth 
at  almost  any  age,  but  more  frequently  in 
advanced  years ;  such  deposits  are  an  indica- 
tion of  a  degeneration  of  tlie  pulp,  which 
becomes  inflamed  or  sclerotic.  Pulp-stones 
are  often  associated  with  an  inflammation  of 
the  pulp  that  is  difficult  to  diagnose  ;  tliey  usu- 
ally occur  in  teeth  whose  pulps  are  subjected 
to  some  form  of  chronic  irritation,  such  as 
abrasion,  erosion,  exposure  of  the  neck  or  roots 
of  a  tootli,  a  large  cavity  or  filling.  Teeth  may 
have  i3ulp-stones  in  them  for  a  lifetime  and  cause 
no  inconvenience  ;  it  is  only  when  degeneration 
has  gone  so  far  that  death  or  infection  supervenes 
that  any  treatment  is  necessary.  The  only 
certain  means  of  diagnosis  before  the  pulp- 
chamber  is  opened  is  a  radiograph.  The  whole 
pulp  may  become  a  solid  calcific  mass  sur- 
rounded by  degenerated  tissue,  which  is  ex- 
ceedingly sensitive,  but  does  not  bleed.  In 
single-rooted  teeth  it  is  often  cone-shaped,  and 
any  movement  at  the  orifice  of  the  cavity  acts 
like  a  spear  tlinist  into  the  nerves  at  the  apex ; 
in  multi-rooted  teeth  the  pulp-chamber  may 
be  filled  with  one  piece,  while  the  canals  may 
have  several  granules  or  be  entirely  free,  or 
the  whole  pulp  may  be  literally  filled  with  fine 
granules  like  grains  of  sand. 
i      The  only  treatment,  when  any  is  necessary. 


464 


is  devitalization  of  the  remaining  living  tissue, 
and  removal  of  all  of  the  contents  of  the  canals. 
If  the  tissues  become  inflamed,  all  the  difficulties 
of  devitalizing  an  inflamed  pulp  are  met  with, 
and  in  addition  those  due  to  the  presence  of 
calcific  tissue,  which  will  not  absorb  arsenic 
nor  become  devitalized  beyond  the  point  of  ap- 
plication. If  the  pulp  tissue  contains  granular 
deposits  no  unusual  difficulties  mil  occur.  If 
there  are  no  acute  symptoms,  it  is  best  to  rely 
upon  applying  the  arsenic  to  the  dentine  for 
a  long  time ;  pressure  anaesthesia  -n-ill  very 
rarely  succeed.  If  acute  symptoms  are  present  , 
and  pulp-stones  are  diagnosed,  either  local  or  { 
general  anaesthesia  is  the  oijy  hope ;  while 
the  pulp  is  thus  anaesthetized,  a  rapidly  revolv- 
ing burr  should  be  plunged  into  the  pulp- 
chamber,  and  as  soon  as  free  haemorrhage  is 
obtained  arsenic  may  be  applied  with  an  assur- 
ance of  no  more  pain  and  a  fair  certainty  of 
devitalization;  it  may  be  advisable  to  pass  a 
fine  reamer  up  the  canal  if  nodules  are  suspected. 
Management  of  Pulps  in  Pyorrhoea. — It  is 
thought  by  many  operators  of  long  experience 
in  the  treatment  of  pyorrhoea,  that  better  results 
are  obtained  when  the  pulps  are  removed ;  it 
is  explained  that  the  periodontal  membrane 
gets  additional  stimulation  or  nourishment 
when  the  pulp  has  been  devitalized.  In  many 
cases  of  pyorrhoea  the  pulp  becomes  irritated 
from  changes  of  temperature  or  from  chemicals, 
because  so  much  of  the  root  of  the  tooth  has 
become  exposed.  In  multi-rooted  teeth  one 
root  may  become  the  seat  of  pyorrhoea  until 
even  the  apex  is  reached,  while  the  other  root 
or  roots  may  be  perfectly  normal  aiad  secure 
in  position.  Pain  may  occur  in  the  pulp  of 
the  diseased  root,  which  will  need  devitalization. 
A  small  hole  may  be  cut  through  the  enamel, 
and  arsenic  applied  for  a  few  days,  and  then  a 
further  cut  made  until  sensation  is  reached, 
when  another  application  may  be  made.  At 
the  next  sitting  the  pulp  will  probably  be  found 
dead,  if  there  has  not  been  too  much  previous 
inflammation. 

Management  of  Pulps  of  Teeth  used  as  Abutments 
for  Bridges  or  to  support  Crowns  or  Large  Fillings 
with  Posts. — It  has  been  observed  that  the  pulp 
of  teeth  used  as  abutments  for  bridges  and 
covered  with  a  gold  cap  very  frequently  lose 
their  vitality.  In  fact  it  is  believed  by  some 
that  the  pulp  of  every  tooth  that  is  covered 
with  a  gold  cap,  or  that  is  to  receive  a  large 
metallic  filling,  should  be  devitalized,  because 
sooner  or  later  it  will  die.  Such  is  a  most 
radical  view.  No  tooth  that  has  lost  its  pulp 
will  bear  as  much  jjressure,  last  as  long,  or  feel 
as  comfortable,  as  if  its  pulp  had  been  alive. 
It  has  been  suggested  that  pulps  die  under  gold 
caps  and  large  fillings  because  the  oxide  of 
zinc     used     in     the     oxy-phosphate     contains 


arsenic ;  this  view  has  not  been  substantiated 
by  analysis  of  oxides  or  phosphates  used.  A 
more  reasonable  explanation  of  the  death  of 
pulps  of  teeth  used  as  abutments  is  overwork 
of  the  abutment ;  in  the  case  of  single  caps  or 
large  metal  fillings,  thermal  changes  are  probably 
responsible.  In  both  classes  of  work  it  might 
be  wise  to  devitalize.  If  the  pulp  is  devitalized, 
the  patient  will  certainly  not  bring  so  much 
pressure  to  bear  upon  the  bridge,  and  the  abut- 
ment will  last  longer,  but  the  bridge  will  be  less 
useful  while  it  does  last.  Notwithstanding  the 
arguments  that  have  been  advanced  by  such 
authorities  as  Hungerford,  Goslee,  and  Broomell, 
the  experience  of  a  large  number  of  careful 
observers  is  that  no  pulp  should  be  devitalized 
that  can  be  retained  alive,  and  that  even  in 
cases  of  abutments,  cap  crowns,  and  large 
fillings,  better  results  may  be  secured  with  live 
pulps. 

Discoloration  of  the  Teeth  during  Devitalization. 
Other  things  being  equal,  the  later  in  life 
devitalization  occurs,  and  the  shorter  the  time 
the  pulp  remains  in  the  tooth  after  it  is  dead, 
the  less  are  the  chances  of  discoloration.  It  is 
impossible  to  give  a  patient  an  assurance  that  a 
tooth  will  not  become  discoloured  after  the  pulp 
has  been  devitalized.  Teeth  whose  pulps  are 
dead  are  always  a  different  colour  from  those 
having  living  pulps ;  the  discoloration  in  some 
cases  is  very  slight,  while  in  others  it  is  of  a  deep 
bluish-blacit.  Some  teeth  are  so  open  in  struc- 
ture that  the  red  blood -cells  seem  to  penetrate 
the  dentine  as  soon  as  the  pulp  has  been  devital- 
ized ;  they  become  pink  in  colour,  and  no 
amount  of  bleaching  will  prevent  them  from 
finally  turning  black.  If  one  tooth  in  the 
mouth  turns  pink  by  devitalization,  all  the  rest 
are  likely  to  do  the  same  if  devitalized.  If  the 
pulp  could  be  desensitized  and  removed  without 
haemorrhage,  and  the  root  and  cavity  filled  at 
once,  discoloration  would  not  be  likely  to 
occur. 

Baird  (Canada)  devitalized  the  pulp  of  a 
central  incisor  for  a  young  girl,  and  the  tooth 
turned  pink  and  afterwards  black.  The  pa- 
tient was  deterred  from  having  conservative 
operations  done,  and  applied  to  Baird  about 
fifteen  years  afterwards  to  have  all  the  teeth 
and  roots  remaining  in  the  maxilla  removed. 
Baird,  remembering  the  pink  colour  that 
followed  an  arsenical  api^lication,  determined, 
before  extracting,  to  find  out  whether  the  same 
result  would  occur  if  any  of  the  remaining 
pulps  were  devitalized.  He  found  that  not 
only  devitalization  by  arsenic  caused  the  teeth 
to  become  pink,  but  also  desensitization  by 
cocaine  and  immediate  pulp  removal  gave  the 
same  result.  When  the  teeth  were  extracted 
they  were  sent  to  the  laboratory  of  the  Royal 
College  of    Dental    Surgeons    (Canada),  where 


465 


sections  were  made,  and  examination  under  the 
microscope  revealed  enlarged  tubules  and  an 
abundance  of  inter-globular  spaces. 

If  the  pulp  of  an  anterior  tooth  is  to  be 
removed,  it  should  be  done  as  expeditiously  as 
possible,  neither  moisture  nor  any  other  sub- 
stance being  allowed  access  to  the  canal  or 
cavity,  except  \^'hat  the  operator  intentionally 
puts  there.  He  should  know  what  drugs  and 
what  treatment  are  the  least  likely  to  cause 
discoloration ;  if  at  all  possible  cocaine 
anaesthesia  should  be  used ;  blood  should  not 
be  allowed  to  remain  in  the  cavity;  dryness 
is  the  key  to  success;  dnigs  that  coagulate 
albumen,  or  leave  a  resinous  deposit,  or  are 
discoloured  by  exposure,  should  not  be  used. 
Phenol,  chloride  of  zinc,  and  bichloride  of 
mercury,  are  objectionable ;  colourless  oil  of 
cloves,  oil  of  cajuput,  or  non-coagulating 
campho-phenique,  may  be  used  as  mild  anti- 
septic dressings,  if  the  canal  cannot  be  at  once 
filled.  The  root-filling  should  be  a  yellowish- 
white  oxy-chloride  of  zinc.  The  cavity  in  the 
tooth  should  be  at  once  filled ;  if  this  is  impos- 
sible an  impermeable  temporary  filling  should 
be  used. 

REMOVAL   OF   PULPS 

Opening  into  Pulp-chambers. — Tlie  first  essen- 
tial in  opening  into  pulp-chambsrs  for  access 
to  the  root-canals  is  complete,  free,  and  un- 
obstructed access;  the  second  essential  is  to 
gain  such  access  with  as  little  loss  of  strength 
of  the  tooth  as  possible.  Access  to  the  pulp- 
chamber  does  not  always  give  access  to  the 
canals ;  this  should  be  kept  in  mind  when  cut- 
ting through  the  crown  of  the  tooth  to  the  pulp- 
chamber.  The  strength  of  the  tooth  is  in  the 
dentine ;  large  openings  may  be  made  at  or  t 
near  the  occlusal  surfaces,  but  if  much  cutting 
is  done  near  the  neck  of  the  tooth  the  support 
of  the  crown  is  gone.  By  choice,  the  pulp- 
chamber  should  be  reached  through  a  cavity 
or  a  filling,  when  such  a  position  will  give  access 
to  the  canals.  If,  however,  a  good  filling  exists 
in  a  molar  or  premolar,  it  is  not  necessary  to 
remove  it ;  the  tooth  should  be  cut  into  as  if  the 
filling  did  not  exist.  Access  to  the  canals  of 
the  anterior  teeth  cannot  be  obtained  by  drilling 
through  an  approximal  filling,  without  dis- 
lodgement  of  the  filling ;  if  the  filling  is  in  good 
condition,  a  direct  opening  to  the  canals  can  be 
made  from  the  lingual  aspect. 

Technique. — If  the  enamel  is  not  broken,  the 
most  suitable  instrument  wdth  which  to  reach 
the  dentine  is  a  stone.  If  the  situation  will  not 
permit  the  use  of  a  stone,  a  drill  made  from  an 
old  burr  ^^■ill  cut  through  the  enamel  better  than 
any  form  of  burr ;  the  drill  must  be  frequently 
sharpened ;  if  the  point  is  dipped  into  oil  or  \ 
vaseline  it  will  cut  better  and  generate  less  heat.  | 


As  soon  as  the  dentine  is  reached  a  round  burr 
will  cut  more  satisfactorily  than  any  other 
instrument.  A  drill  will  cut  amalgam  or  gold 
better  than  a  burr.  Before  the  pulp-chamber  is 
reached,  if  there  is  any  reason  why  the  instru- 
ment should  not  be  allowed  to  plunge  into  it, 
the  opening  should  be  enlarged  with  a  large 
round  burr.  As  the  pulp  is  reached,  a  horn  will 
be  opened  before  the  instrument  drops  into  the 
cavity;  a  small  burr  may  be  passed  into  the 
opening,  cutting  sideways  to  avoid  pressui-e  into 
the  pulp-chamber.  The  chamber  should  be 
opened  the  full  size  of  the  occlusal  wall  in  molars 
and  premolars.  The  inexperienced  operator 
often  believes  that  he  has  found  the  root-canals 
of  an  upper  premolar  when  he  has  only  opened 
into  the  chamber  through  the  buccal  and 
lingual  horns ;  the  same  mistake  may  occur  in  a 
molar.  Even  the  experienced  operator  may 
be  in  some  doubt  in  cases  where  the  pulp  has 
much  receded ;  all  doubt  can  be  set  aside  by 
passing  a  hooked  broach  or  a  small  hatchet- 
excavator  through  the  oiiening ;  if  after  being 
turned  round  it  catches  when  withdrawn,  there 
is  evidence  that  the  occlusal  wall  of  the  pulp- 
chamber  has  not  been  all  cut  away. 

If  a  cavity  exists  in  the  tooth  large  enough  to 
expose  the  pulp,  all  the  overhanging  enamel  and 
carious  dentine  should  be  cut  away  with  chisels 
and  large  spoon-excavators.  The  cavity  should 
be  washed  out  with  tepid  water,  and  dried  with 
an  absorbent  or  a  blast  of  warm  compressed 
air.  As  much  tooth  tissue  should  be  cut  away 
as  will  be  necessary  for  the  final  preparation  of 
the  cavity  for  the  reception  of  the  filling,  or 
for  access  to  the  pulp-chamber  or  canals.  The 
pulp-chamber  should  now  be  opened  from  the 
exposure  laterally  with  a  round  burr  (not 
allowed  to  drop  into  the  chamber,  and  drawn 
outwards  as  it  cuts).  No  sharp-cornered  rotating 
instrument  should  be  used  for  this  purpose,  lest 
corners  be  made  in  the  chamber  against  which 
broaches  ^^■ill  strike  when  attempts  are  made  to 
reach  the  canals.  If  the  canal  of  a  single-rooted 
tooth  is  to  be  reached  from  an  ap- 
proximal cavity,  and  the  approximo- 
occlusal  corner  of  the  tooth  is  to  be 
preserved  as  much  as  possible,  there 
vfiW  be  no  opportunity  to  get  direct 
access  to  the  canal.  To  assist  in 
getting  access,  a  small  round  burr 
may  be  passed  up  the  canal  as  far 
as  possible,  and  pressed  against  the 
approximal  wall  of  the  canal  as  it  is 
drawn  towards  the  occlusal  surface ; 
this  will  enlarge  the  canal  towards  the  Fig.  520. 
approximal  surface,  and  give  access 
without  cutting  away  tissue  that  is  of  assistance 
to  the  strength  of  the  tooth  (see  Fig.  520).  In 
young  anterior  teeth  the  horns  of  the  jjulp  are 
often  very  thin  labio-lingually,  and  require  a 


466 


good  deal  of  attention  to  remove  the  pulp, 
esjiecially  if  the  opening  to  the  chamber  is  made 
from  the  lingual  aspect  or  from  an  approximal 
cavity  near  the  neck  of  the  tooth. 

Removal  of  Pulps. — Of  all  the  ojierations  in 
dentistry,  removing  pulps  requires  the  most 
skill  and  perseverance.  It  is  necessary  to  have 
a  good  kno^^•ledge  of  dental  anatomy,  familiarity 
with  the  strength  of  instruments,  skill  in  their 
use,  and  a  cultivated  sense  of  touch.  Wlien  one 
thinks  of  a  cone-shaped  or  slit-shajjed  cavity 
of  unknown  length  and  often  so  fine  and  tortuous 
that  the  finest  steel  bristle  will  not  pass  into  it, 
placed  in  a  position  awkward  to  get  at,  and 
filled  with,  a  tissue  that  is  attached  at  a  fine 
opening  at  the  end,  and  is  not  often  strong 
enough  to  break  at  the  attachment  when  pulled 
upon,  it  is  no  wonder  that  so  much  attention 
is  devoted  to  the  subject.  One  of  the  chief 
difficulties  is  to  pass  an  instrument  into  the 
canal  that  is  already  full,  and  get  hold  of  the 
pulp,  without  pressing  it  into  the  fine  end  of 
the  canal. 

It  is  not  usually  difficult  to  remove  the  pulp 
from  single-rooted  teeth  of  young  patients. 
The  difficulties  increase  as  the  canals  become 
smaller,  flatter,  more  tortuous,  and  more  diffi- 
cult of  access.  It  is  physically  impossible 
to  remove  all  the  pulp  from  some  flat  tortuous 
canals  in  molar  teeth,  without  taking  the  risk 
of  puncturing  the  root  or  breaking  a  jjroach  in 
the  canal,  or  of  causing  an  irritation  with 
chemicals  that  would  be  more  detrimental  to 
the  longevity  of  the  tooth  than  the  small  amount 
of  tissue  that  might  have  been  left. 

It  must  not  be  understood  from  the  fore- 
going that  the  writer  would  recommend  leaving 
dead  pulp  tissue  in  a  canal  from  which  it  is 
possible  to  remove  it  :  dead  organic  matter 
cannot  be  retained  in  the  human  body  in  the 
presence  of  moisture  without  danger  of  septic 
infection.  The  possibilities  of  infection  are  in 
proportion  to  the  amount  of  tissue  left,  and  the 
possibilities  of  sterilization  are  inversely  so. 
It  is  impossible  to  sterilize  pulp  tissue  perman- 
ently by  any  known  method  :  because  a  tooth 
so  treated  gives  no  trouble  in  one  patient,  it 
does  not  follow  that  the  same  treatment  -ndll 
be  equally  successful  in  another.  A  tooth  that 
does  not  remain  in  a  perfectly  normal  condition 
for  the  remainder  of  the  patient's  life  caimot 
be  said  to  have  been  treated  v.-ith  entire  success. 
Many  teeth  that  have  lost  their  jjulps  do  not 
ache  violently,  but  gradually  lose  their  useful- 
ness; they  get  tender  to  bite  upon  now  and 
again,  heavy  pressure  always  hurts,  the  roots 
become  discoloured,  the  gum  recedes  from  the 
neck,  the  periodontal  membrane  becomes 
detached,  the  tooth  loosens,  and  has  finally  to 
be  removed  because  it  gets  very  tender  or  is  a 
nuisance;    the  end  of  such  a  root  is  markedly 


absorbed  leaving  a  rough  honeycombed  surface. 
This  is  the  history  of  a  tooth  devitalized  in 
early  life,  or  of  one  in  which  there  was  irritation 
by  arsenic  or  cocaine,  or  some  pulp  tissue 
remained  but  never  caused  pus-formation — a 
chronic  inflammation;  the  cementum  and 
periodontal  membrane  gradually  die  and  the 
root  is  exfoliated  as  a  foreign  substance.  An 
improperly  filled  root-canal  with  a  large  apex 
may  bring  about  the  same  result. 


Fig.  521.  —  Donaldson 
Bristles,  hooked,  rough- 
ened, and  spiral  (S.  S. 
White  make).  (Dental 
Manufacturing  Co., Ltd.) 


Fig.  522.  —  Donaldson 
Root-canal  Cleansers 
(S.  S.  White  make). 
[Dental  Manujacturing 
Co.,  Ltd.) 


Dentists  are  better  able  to  cope  with  this 
difficult  operation  now  than  at  any  previous 
time,  because  of  a  better  knowledge  of  dental 
anatomy,  and  a  better  training;  and  more 
especially  because  of  the  great  improvement  in 
instruments  during  the  past  ten  or  fifteen  years. 

Instruments. — An  instrument  to  be  useful  as 
a  pulp-extractor  must  be  fine,  strong,  flexible, 
tough,  and  sufficiently  rigid  to  be  forced  into 
the  canal.  Pulp-extractors  are  designed  to 
entangle  or  hook  on  to  the  pulp.  They  are 
hooked,  barbed,  or  spiral ;  and  are  made  of 
steel — round,  square,  or  triangular  in  section 
(see  Figs.  521,  522,  523,  524). 


467 


Technique. — Pulps  that  have  been  recently 
devitalized  or  desensitized  may  be  removed  by 
winding  a  few  strands  of  a  long-fibred  cotton- 
wool on  a  smooth  broach,  and  gently  j)assing 


Fig.  523. — DonaldsOH  pattern  Root-canal  Cleanser 
with  extra  short  handle.  (Dental  Manujacturing 
Co.,  Ltd.) 

it  up  the  canal  with  a  rotary  motion  until  the 
pulp  is  entangled  in  the  fibres  of  cotton  and 
thus  extracted  when  the  broach  is  withdrawn; 
this  operation  may  have  to  be  repeated  several 


FlQ.  524. — Broaches,  barbed  and  spiral,  with  flexible 
handles  (magnified).  (Dental  Manujacturing  Co., 
Ltd.) 

times  before  the  pulp  is  caught.  Barbed 
broaches  are  passed  up  the  wall  of  the  canal 
when  there  is  room,  and  rotated  and  withdrawn. 
It  is  necessary  to  take  great  care  of  broaches, 
because  the  steel  is  so  fine  that  the  slightest 


rusting  or  corroding  might  cause  them  to  break 
at  a  critical  moment.  They  should  be  kept 
clean  and  bright  at  all  times.  Broaches  are 
made  short,  with  a  knob  at  the  end,  for  use  in  the 
molar  region,  and  long  and  flexible  for  placing 
in  a  holder.  Broach-holders  should  be  light, 
easily  adjusted,  and  of  convenient  length;  a 
heavy  broach-holder  is  so  much  out  of  balance 
with  a  fine  broach  that  sensations  are  not 
readily  appreciated.  Each  broach  should  be 
placed  in  its  own  holder,  and  not  removed  until 
it  is  no  longer  serviceable.  There  should  be 
ready  for  use  at  all  times  at  least  four  smooth 
broaches  :  a  very  fine,  long,  flexible  one ; 
another  just  as  fine  at  the  end,  but  gradually 
becoming  thick  and  rigid,  and  intended  for 
forcing  its  way  into   fine   canals;    a  third  of 

! 


A 


A 


\  il 


Fig.   525. — Beutelroo    Drills   for  straight  hand-piece. 
(Messrs.  Claudius  Ash,  Sons  cfc  Co.,  Ltd.) 

medium  size  for  general  use ;  and  a  fourth 
heavy  and  strong  with  a  square  end.  Two 
hooked  broaches,  one  fine  and  one  coarse,  will 
meet  most  conditions.     Two  or  three   barbed 


\ 


I        1        II        ^1        '         1 

LJ        [3         n         U         C  I         LI 

Fig.  526. — Beutelroc  Drills  for  right-angle  hand-piece 
(Messrs.  Claudius  Ash,  Sons  <t  Co.,  Ltd.) 

broaches ;  three  universal  reaming  broaches, 
fine,  medium,  and  coarse ;  and  one  or  two 
special  broaches,  should  make  up  a  fair  assort- 
ment for  general  use.  For  special  cases  of 
drilling  through  the  apex  the  Beutelroc  drill, 
or   some   other  drill   that   will   make   progress 


468 


ahead  and  not  bind  in  the  canal,  is  necessary. 
The  Gates-Glidden  drill  is  sometimes  useful,  or 
some  such  instrument  with  a  flexible  shank, 
which  will  follow  a  canal  and  enlarge  it  (see 
Figs.  525,  526,  527,  528,  529). 


Fig.  527. — Gates-Glidden  Drills  for  straight  hand- 
piece (magnified  figure  on  riglit).  (Messrs.  Claudius 
Ash,  Sons  <&  Co.,  Ltd.) 

It  is  not  necessary  to  use  a  barbed  or  hooked 
triangular  or  roughened  broach  to  wind  cotton- 
wool upon  so  that  it  may  be  passed  into  a 
canal  and  -withdrawn  without  dislodgement  of 
the    cotton-wool.     Such    instruments    are    at 


t 


iJl 


fibres  will  cover  the  end;  with  the  left  thumb 
gather  some  of  the  fibres  and  press  them  upon 
the  broach,  holding  it  tightly,  and  leaving  hold 
of  the  handle  with  the  right  fingers,  and  grasp- 
ing some  of  the  loose  fibres  and  the  broach 
between  the  right  thumb  and  forefinger.  Now 
rotate  the  broach  between  the  right  thumb  and 
finger,  at  the  same  time  holding  tightly  with  the 
left  thumb  and  finger.  The  tightness  of  the 
wind  depends  upon  the  tightness  of  the  hold  of 
the  left  thumb  and  finger  during  winding.  It 
is  wise  always  to  rotate  in  the  same  direction; 
because  when  the  broach  is  being  carried  into 
the  canal,  it  may  be  rotated  in  the  same 
direction  in  which  it  was  wound  ;  and  when  it  is 
desired  to  loosen  the  cotton-wool  and  leave  it  in 


Fig.  528. — Gates-Glidden  Drills  for  right-angle  hand- 
piece.     {3Iessrs.  Claudius  Ash,  Sons  dk  Co.,  Ltd.) 

once  entangled  with  the  cotton-wool  and  cannot 
be  used  a  second  time,  but  with  a  smooth 
broach  the  cotton-wool  can  be  at  once  with- 
drawn and  a  fresh  piece  put  on.  The  method 
of  use  is  as  follows  :  Spread  a  few  strands  of 
long-fibred  cotton  upon  the  left  forefinger ;  on 
the  centre  of  this  place  the  broach  so  that  the 


Fig.  529. — Gates-Glidden  Drills  with  spring  stem,  for 
straight  hand-piece.  (Messrs.  Claudius  Ash,  Sons 
cfc  Co.,  Ltd.) 

the  canal,  the  broach  may  be  rotated  in  the 
opposite  direction. 

If  the  pulp  cannot  be  removed  from  the  root- 
canal  of  any  of  the  round-rooted  teeth  by  this 
method,  the  chances  are  that  the  tissue  has  been 
forced  into  the  apex  of  the  root.  The  inex- 
perienced operator  will  be  deceived  into  thinking 
that  he  has  removed  the  pulp  in  small  pieces, 
when  as  a  matter  of  fact  he  has  taken  out  the 
merest  shreds,  or  perhaps  only  blood-clots. 
Each  piece  of  tissue  that  is  withdrawn  should 
be  spread  out  upon  a  piece  of  absorbent  paper, 
so  that  the  amount  of  tissue  may  be  noted ; 
the  fine  end  of  the  pulp  tissue  is  readily  made 
out,  and  efforts  should  not  cease  until  it  is 
found.  A  fine  hooked  broach  -will  often  catch 
a  piece  of  pulp  that  has  been  forced  into  the 
apex  of  the  root ;  or  a  Kerr  or  Downie  reamer 
(see  Figs.  530,  531),  as  large  as  will  pass  into 
the  canal,  will  often  catch  such  a  piece ;  it  will 


469 


at  all  events  so  mash  it  up  that  it  may  be 
brought  a-v^-ay  ^^■ith  a  barbed  broach,  or  cotton- 
wool wound  round  a  smooth  broach. 

In  case  all  the  tissue  has  not  been  certainly 
removed,  a  50  %  solution  of  sulphuric  acid 
may  be  ^^■orked  into  the  canal  ^^-ith  a  den- 
tal alloy  broach.     The  sulphuric  acid  may  be 


Q  % 


Fig.  530.- 


-Kerr  Reamer.     {Dental  Manufacturing  Co.. 
Ltd.) 


carried  to  the  cavity  between  the  points  of  the 
dressing-forceps.  The  points  are  held  together, 
dipped  into  the  sulphuric  acid,  \\'ithdrawn, 
carried  to  the  cavity,  and  placed  in  contact 
with  the  tooth  where  the  acid  is  required ;  as 
the  points  are  separated  the  acid  ■\\ill  run  into 
the  cavity.  With  upper  teeth  it  may  be  neces- 
sary to  tip  the  chair  back  and  ask  the  patient 


Fig.    531. — Downie  Reamer.       {Dental  Mantijacturing 
Co.,  Ltd.) 

to  raise  the  chin ;  this  will  at  least  place  the 
upper  teeth  on  a  horizontal  i^lane,  and  allow 
the  acid  to  run  into  the  canal.  After  the  acid 
has  been  pumped  up  and  down  in  the  canal  for 
some  time,  the  excess  may  be  neutralized  with 
a  saturated  solution  of  bicarbonate  of  soda 
worked  into  the  canal ;    an  effervescence  v,i\\ 


occur,  which  will  carry  with  it  any  shreds  of  the 
remaining  jiulp.  The  sulphuric  treatment  may 
be  repeated  several  times  if  thought  necessary. 
Care  must  be  taken  that  the  acid  is  completely 
neutralized,  or  there  \v'lll  be  considerable  irrita- 
tion at  the  ape.x;  on  account  of  the  irritation 
that  often  follows  this  operation,  it  is  not  wise 
to  fill  the  root-canal  at  the  same  sitting ;  if  a 
bicarbonate  of  soda  solution,  with  a  mild 
antiseptic  dressing,  is  applied  for  a  day  or  two, 
no  irritation  will  occur. 

To  remove  the  pulps  from  flat  tortuous  canals 
of  premolars  and  molars  is  an  entirely  different 
operation  from  the  foregoing ;  there  are  the 
want  of  accessibility,  the  difficulty  of  seeing  the 
canal  openings,  and  the  awkwardness  of  direc- 
tion that  some  of  the  canals  hav^e.  The  openings 
into  the  root-canals  of  flat-rooted  first  upper 
premolars  are  under  the  buccal  and  lingual 
cusps  ;  if  the  broach  is  placed  against  the  buccal 
wall  of  the  pulp-chamber  it  \W11  glide  into  the 
buccal  canal,  and  if  placed  against  the  lingual 
wall  it  will  glide  into  the  lingual  canal.  If  the 
pulp-chamber  of  a  premolar  is  opened  from 
the  occlusal  surface,  it  \vi\\  be  necessary  to  cut  the 
sulcus  medially  and  distally  to  the  medial  and 
distal  pits ;  but  since  the  puliD-chamber  is  \\dde 
bucco-lingually,  the  dentine  should  be  cut  buc- 
cally  and  lingually  as  it  reaches  the  chamber, 
but  should  not  be  cut  through  to  the  occlusal 
surface.  Any  cutting,  medially  or  distally,  to 
remove  the  sulcus  or  fi.ssure,  should  be  only 
the  depth  of  the  enamel ;  the  tendency  of  these 
teeth  is  to  split  medio -distally,  and  cutting 
towards  the  buccal  or  lingual  surface  at  the  depth 
of  the  pulp-chamber  will  not  materially  weaken 
the  tooth. 

The  openings  into  the  root-canals  of  the  first 
upper  molars  are  not  always  easy  of  access. 
The  lingual  root  has  a  fumiel-shaped  opening 
and  a  round  canal  directed  towards  the  palate ; 
a  broach  passed  into  the  pulp-chamber  ^vill 
readily  enter  this  canal.  The  medio-buccal 
root-canal  has  a  wide  slit-shaped  opening, 
slightly  funnel-shaped  (occasionally  there  are 
two  openings,  of  ^^•hich  the  outer  is  the  larger) ; 
the  ojiening  is  always  under  the  medio-buccal 
cusp,  and  can  rarely  be  entered  \\ithout  opening 
through  the  medial  surface  of  the  cro\\-n ;  to 
enter  this  canal  the  broach  should  be  placed 
against  the  medio-buccal  angle  of  the  pulp 
chamber  and  directed  medio-buccally.  The 
opening  of  the  disto-buccal  canal  is  usually 
round  and  opens  abruptly,  and  is  placed  under 
the  disto-buccal  cusp.  This  canal  is  most 
easily  found  by  its  relation  to  the  other  two  ; 
the  three  openings  form  the  apices  of  a  triangle, 
of  which  the  usual  form  is  seen  in  Fig.  532.  The 
second  and  third  molars  are  narrower  medio- 
distally  at  the  neck,  and  as  a  consequence  the 
opening  of  tlie  disto-buccal  root  is  closer  to  the 


470 


other  openings,  until  ui  some  cases  it  is  almost 
in  a  direct  line  between  them.  Occasionally 
the  medio-buccal  root  and  the  lingual  root  of 
the  second  upper  molars  are  blended  into  one 
irregular  canal  situated  near  the  medial  aspect. 
Sometimes  the  roots  of  the  third  upper  molars 
are  blended,  and  only  one  large  cone-shaped 
canal  exists,  but  usually  there  are  three  very 
fine  canals. 

The  lower  incisors  have  canals  wide  medio- 
distally  in  the  crowns,  and  wide  labio-lingually 

Medio-buccal. 


)  ^   Lmgu.il. 


Disto-buccal. 

Fig.  532. — Transverse  section  of  first  right  upper  molar 
at  gum  level. 

in  the  roots ;  sometimes  there  are  two  canals 
ending  in  one  opening  at  the  apex.  Lower 
canines  occasionally  have  a  supplemental  root 
or  knob  in  the  root-canal,  which  the  broach 
will  enter,  and  thereby  cause  the  operator  to 
believe  that  the  root  is  short.  There  is  nothing 
peculiar  about  the  root-canals  of  the  lower 
premolars,  except  perhaps  the  occasionally  very 
fine  apex.  The  distal  root-canal  of  the  first  or 
second  lower  molar  is  easy  of  access ;  the  open- 
ing is  funnel-shaped  and  a  broach  directed 
against  the  distal  wall  of  the  chamber  \vill 
readily  enter  the  canal.  The  medial  root-canals 
are  not  so  easily  entered  ;  the  opening  is  usually 
wide  bucco-lingually  and  very  narrow  medio- 
distally ;  there  are  often  two  openings  and  two 
distinct  canals  joining  in  one  at  the  apex  or 
perhaps  ending  in  two  distinct  openings.  To 
enter  the  medial  canal  through  an  occlusal  cavity 
the  broach  must  be  directed  against  the  medial 
wall  of  the  chamber.  The  canal  is  at  first 
directed  medially,  and  further  do-mi  curves 
distally.  It  is  difficult  to  remove  the  pulp  from 
the  medial  canal  without  cutting  away  the  medial 
surface,  and  occasionally  the  medio-buccal  cusp. 
The  root-canals  of  the  second  lower  molar  are 
finer  than  those  of  the  first,  but  usually  more 
rounded  and  consequently  often  more  easily 
managed ;  there  is  usually  but  one  medial  root- 
canal.  Both  roots  curve  more  in  a  distal 
direction  than  those  of  the  first  molars,  and  this 
makes  them  easier  of  access.  The  third  molar 
usually  has  two  root-canals,  fine  and  markedly 
curved  distaUy ;  occasionally  the  two  roots  are 
blended  into  one,  thus  making  a  large  cone- 
shaped  canal.  The  cro^\^^s  of  third  molars  are  so 
directed  forwards  that  the  canals  are  usually 
easily  entered,  but  they  are  so  fine  that  they 
are  often  very  difiBcult  to  manage.     Koot-canal 


openings  that  are  difficult  to   find   should  be 

!  thoroughly  dried,  or  wiped  with  sulphuric  acid 
and  then  dried ;  this  will  show  the  openings  as 
dark  spots. 

I  The  means  of  entrance  to  the  root-canals  of 
the  premolars  and  molars,  and  the  technique 

I  of  removing  the  pulp  from  the  incisors  and 
canines  havmg  been  described,  it  is  now  only 

\  necessary  to  discuss  methods  especially  designed 
for  the  fine,  flat,  tortuous  root-canals  of  the 
premolars  and  molars.  As  in  the  incisors, 
every  effort  should  be  made  to  remove  the  pulp 
with  cotton-wool  wound  on  a  broach,  or  with 
the  barbed  or  hooked  broach.  These  failing, 
flexible  reamers  may  be  tried,  and  followed  if 
necessary  by  the  Callahan  method. 

Callahan  Treatment  for  Constricted  Root-Canals 

"  In  order  to  develop  the  desirable  technique 
we  select  a  first  left  lower  molar,  from  which 
we  grind  the  buccal  surface  of  crown  and  roots 
sufficiently  to  disclose  the  pulp-chamber  and 
canals.     (See  Fig.  533.) 

"The  medio-buccal  canals  present  an  abrupt 
or  square  entrance  and  are  therefore  not  easy 
to  locate,  or  easy  to  enter  when  found.  A 
No.  5  Donaldson  broach  is  finally  passed  as 
far  as  (b)  on  the  diagram,  where  it  meets  with  a 
constriction.  Below  this  point  we  have  reason 
to  believe  that  the  constricted  canal  contains 
fragments    of   dead    pulp  tissue    or    a    minute 


Fig.   533. — Diagram  to  illustrate  Callahan  treatment 
for  constricted  root-canals.      {Dental  Cosmos.) 

blood  clot  in  a  more  or  less  disintegrated  con- 
dition, which  even  though  mummified  to  the  best 
of  our  ability,  and  sealed  in  this  position,  will 
finally,  in  from  one  to  five  years,  under  the 
influence  of  the  secretions  of  the  body,  become 
food  for  some  itinerant  microbe.  These  pulp 
fragments  should  be  removed,  and  the  canal 
be  put  in  such  a  condition  that  drugs  and  fUling 
materials  may  reach  the  apical  foramen  with 
the  greatest  degree  of  ease  and  accuracy.  To 
this  end  the  mouth  of  the  canal  should  be  en- 
larged, and  its  constrictions  and  curves  made 
easier,  and  its  general  shape  should  be  that  of  an 


471 


attenuated  fumiel.  With  a  Gates-Glidden  drill  ' 
aa  large  as  conditions  will  permit,  we  start  the 
fumiel  shape  at  the  mouth  of  the  canal  (c), 
being  careful  to  have  the  canal  as  dry  as  possible, 
for  it  is  in  the  wet  canals  that  tlie  drills  lock 
and  break.  Be  careful  to  allow  the  drill  to  go 
only  far  enough  to  make  a  pocket,  say,  of  a 
depth  equal  to  half  the  length  of  the  head  of 
the  drill. 

"  A  smaller  Gates-Glidden  drill  will  then 
go  a  little  farther  into  the  canal  {d),  the  operator 
being  careful  to  stop  short  of  a  curve.  Then 
place  a  drop  of  40  %  sulphuric  acid  in  the 
pocket ;  next,  ■i\-ith  a  large  Donaldson  broach 
that  will  enter  the  canal  at  the  extremity  of 
the  pocket  thus  made  (e),  begin  pumpmg, 
enlarging  the  canal  to  the  size  of  that  broach 
as  far  as  possible.  Then  repeat  the  process, 
using  this  time  a  smaller  broach  (/),  keeping 
fresh  acid  in  the  canal  and  continuing  the  gentle 
manipulation  of  the  broach  until  an  obstiiiction 
is  met  with. 

"  Then,  ^^'ith  cotton-wool  or  a  small  sjTinge, 
introduce  into  the  cavity  a  saturated  solution 
of  sodium  bicarbonate,  and  note  what  happens. 
If  there  be  sufficient  acid  m  the  canal,  enough 
carbonic  acid  gas  is  manufactured  to  cause  a 
series  of  rapid  and  easily  noticed  explosions, 
coming  from  the  very  end  of  the  canal,  carrying 
every  particle  of  debris  out  of  it,  and  leaving  it 
cleaner  than  it  can  be  made  by  any  other 
practical  procedure. 

"  The  obstruction  met  with  consists  either  of 
cementum  at  the  apex  of  the  root  or  of  pulp 
tissue  rammed  ahead  of  the  broach.  At  tliis 
point  it  may  be  pertinent  to  inquire  as  to  what 
has  happened  to  the  miaute  fragment  of  pulp 
tissue  in  the  remaining  ^'^  of  an  inch  of 
the  canal  at  the  apex.  It  is  reasonable  to 
suppose  that  the  acid,  by  the  time  it  readies 
this  poiut,  is  neutraUzed  a  little  at  least,  and  the 
pulp  fragments  have  been  changed  somewhat, 
carbonized  slightly  and  somewhat  hardened, 
but  are  still  freely  soluble  in  the  presence  of 
sodium-potassium. 

"  The  enlargmg,  straightening,  and  smoothing 
of  the  canal,  as  above  described,  enables  us  to 
carry,  on  a  worn  No.  5  Donaldson  broach,  small 
particles  of  sodium-potassium  to  these  pulji 
fragments  with  a  reasonable  certainty  that  they 
will  be  dissolved  or  broken  up  by  the  strong 
alkali.  Then  the  soapy  residue  should  be  got 
rid  of,  lest,  if  left  in  the  apex  or  apical  space, 
it  would  in  time  be  so  changed  that  it  would 
become  attractive  to  germ-life.  Such  is  the  un- 
certainty of  getting  \\'ater  to  it  with  sufficient 
force  that  I  have  made  a  second  application  of 
sulphuric  followed  by  a  sodium  bicarbonate  solu- 
tion, witli  the  idea  that  the  liberation  of  the 
resultant  carbonic  acid  gas  ^^■ould  free  the  canal 
of  every  deleterious  substance." 


MANAGEMENT    OF    ROOT-CANALS    OF   TEETH 
HAVING   DEAD   PULPS 

The  pulp-chamber  and  root-canals  of  teeth 
in  which  the  pulp  has  died  under  a  filling 
or  from  a  shock  or  some  other  cause,  and 
is  not  exposed,  may  be  apparently  dry  and 
odourless  ;  the  jjiocess  is  known  as  dry  gangrene. 
But  if  the  chamber  and  canals  are  filled  with  a 
wet  semi-solid  mass  of  gray,  or  even  black, 
colour,  and  of  exceedingly  foul  odour,  the 
jirocess  is  known  as  moist  gangrene.  If  a 
gangrenous  pulp  is  dark  in  colour  and  emits  a 
foul  odour,  its  management  requires  much  care  ; 
when  such  canals  are  opened  an  alveolar  abscess 
often  develops  in  spite  of  anj-thing  that  may  be 
done.  Either  dry  or  moist  gangrenous  pulps 
may  be  accompanied  by  pain,  but  as  a  nile 
the  dry  variety  is  ijaiiiless.  Moist  gangrenous 
or  putrescent  jiulps,  especially  the  f)aiiiful 
variety,  are  often  associated  with  an  alveolar 
abscess.  It  is  difficult  to  be  certain  at  the  first 
sitting  whether  an  abscess  exists  or  not ;  for 
this  reason  the  first  treatment  of  each  case 
should  be  identical.  Since  the  introduction 
of  formaldehyde  as  a  constituent  of  drugs 
for  treatmg  infected  root-canals,  much  better 
success  attends  tlie  management  of  these  cases. 

Dry  Gangrenous  Pulps  tJiat  are  iiot  exposed 
and  not  painful,  are  apparently  the  most 
imiocent  cases  coming  under  the  dentist's  care, 
but  are  really  the  most  treacherous.  Broaches 
should  be  very  carefully  passed  into  such  canals. 
If  a  positive  diagnosis  could  be  made  that  no 
infection  existed,  the  canal  might  be  at  once 
filled ;  but  such  is  not  possible.  The  majority 
of  these  canals  may  be  at  once  filled ;  this  fact 
has  led  many  operators  to  conclude  that  all 
gangrenous  pulps  are  cases  for  immediate  root- 
filling.  The  occasional  incidence  of  violent 
pain,  swelling,  loss  of  tooth,  and  even  perhaps 
life,  teaches  caution  in  these  cases.  No  pulpless 
tooth  should  be  opened  except  under  the  most 
careful  asej)tic  precautions ;  the  rubber-dam 
should  if  possible  be  used,  not  only  to  prevent 
moisture  from  getting  into  the  cavity,  but  also 
to  help  in  perceiving  any  odour  or  moisture 
from  the  canals.  It  is  never  safe  to  fill  imme- 
diately any  canal  that  has  had  a  gangrenous 
pulp.  It  is  wiser  to  open  into  the  pulp-chamber, 
and  ^\'ith  a  fine  hooked  broach  withdraw  any 
dry  or  disintegrated  tissue  that  may  be  caught, 
without  pressing  into  the  root-canals  ;  to  insert 
in  the  chamber  a  dressing  of  formaldehyde  and 
tricresol,  and  seal  tightly  for  three  or  four  days. 
If  the  tooth  was  not  aching  when  the  patient 
applied  to  the  dentist,  notliing  should  be  done 
that  might  cause  pain;  there  is  nothing  so 
detrimental  to  the  good  name  of  dentistry  as 
for  patients  to  be  able  to  say  that  their  teeth 
were  comfortable  when  they  \\  ent  to  the  dentist, 


472 


but  that  pain  afterwards  occurred.  No  chances 
sliould  therefore  be  taken  of  setting  up  a  painful 
periodontal  infection  and  the  possible  conse- 
quences, by  forcing  a  large  broach  into  an  empty 
root-canal ;  such  may  carry  infection  from  the 
canal  to  the  apex,  and  light  ujj  an  inflammation 
that  will  take  days,  or  jjerhaps  weeks,  to  subside. 
Some  of  these  cases,  which  seem  to  be  so  inno- 
cent, may  have  a  slightly  foul  celour,  which 
should  be  taken  as  a  warning.  Ihe  violent 
infection  that  often  follows  opening  into  a  dry 
gangrenous  puliJ-chamber,  is  said  to  be  induced 
by  the  entrance  of  oxygen,  this  being  the  only 
element  lacking  to  peimit  full  activity  of  the 
dormant  organii-ms.  An  immediate  disinfection 
is  therefore  desirable,  such  as  can  be  affected  by 
formalin  vapour. 

Formaldehyde  is  an  exceedingly  irritating 
drug.  The  vapour  is  soluble  in  water  and  very 
penetrating;  it  soon  loses  its  strength  by 
evaporation.  When  a  40  %  solution  is  placed 
in  a  pulp-chamber,  and  no  tissue  intervenes 
between  it  and  the  apex,  extreme  irritation 
may  supervene ;  in  fact,  the  tissues  of  some 
persons  are  extremelysusceptible  to  the  irritating 
effects  of  formaldehyde,  and  very  mild  solutions 
should  be  used  for  jiatients  whose  mucous 
membranes  are  at  all  irritable  to  abrasion  or 
drugs.  To  overcome  these  irritating  properties, 
and  yet  retain  the  penetrating  and  disinfecting 
properties,  many  combinations  have  been 
made  with  other  diugs.  The  desire  is  to  have 
the  vapour  given  off  slowly,  and,  as  soon  as  it 
has  all  gone,  to  have  some  other  drug  present 
that  Mill  act  as  a  disinfectant.  This  combina- 
tion has  been  well  secured  by  the  suggestion 
of  George  W.  Cook,  Chicago,  U.S.A.,  to  mix 
formaldehyde  and  tricresol.  They  may  be  mixed 
in  several  proportions,  according  to  the  dis- 
infecting or  penetrating  powers  required.  For  | 
oidinary  use,  equal  parts  of  each  is  satisfactory, 
but  if  a  deeji  mass  of  putrescent  matter  is  to 
be  penetrated,  the  proportion  of  formaldehyde 
may  be  increased  ;  if  little  or  nothing  intervenes 
between  it  and  live  tissue,  much  less  should  be 
used.  There  has  been  no  single  drug,  or  com-  | 
bination  of  drags,  that  has  been  as  satisfactory 
for  treating  infected  root-canals  as  formaldehyde 
and  tricresol.  Solidified  formaldehyde,  under 
the  name  of  formacoid,  has  been  used  with 
satisfactory  results.  Formaldehj'de  mixed  with 
powders  to  prevent  its  rapid  evaporation  has 
had  some  advocates. 

In  the  case  of  dry  gangrenous  pulps  that  are 
fMin/vl,  the  pain  is  immediately  relieved  by 
opening  the  pulp-chamber,  if  it  has  not  already 
lasted  for  several  hours;  even  then  it  wdll  be 
relieved  in  fifteen  or  twenty  minutes.  If  the 
pain  is  relieved  there  should  be  no  attempt  made 
to  open  up  the  canals.  A  dressing  of  form- 
aldehyde and  tricresol  should  be  sealed  in  the   , 


pulp-chamber  for  a  few  days.  At  the  second 
sitting  the  rubber-dam  should  if  possible  be 
used,  and  the  teeth  isolated  by  it  should  be 
sterilized  with  a  strong  disinfectant  and  alcohol. 
If  there  has  been  no  pain  in  the  interval,  and 
there  is  no  present  tenderness  of  the  periodontal 
membrane,  no  odour  or  moisture  in  the  dressing, 
or  in  the  canals  when  they  are  cleaned  out,  the 
root  may  be  filled.  Fine  hooked  broaches  or 
Donaldson  cleansers  should  be  used  to  remove 
any  of  the  contents  of  the  canals;  flexible 
reamers  may  be  worked  up  the  canals.  When 
the  operator  is  satisfied  that  the  canals  are 
cleaned  out  to  the  end,  they  should  be  wiped 
out  with  alcohol  and  dried  with  air  and  a  heated 
root-canal  drier,  and  then  filled. 

Moist  Gangrenous  or  Putrescent  Pulps  may  or 
may  not  be  associated  with  an  alveolar  abscess 

'  or  pain.  The  prxlp-chamber  may  be  open  or 
closed.  The  painless  variety  that  is  open  should 
be  treateel  by  excavating  all  the  caries  in  the 
cavity,  and  opening  the  pu]j)-chamber  as  much 
as  is  desired  for  future  treatment  and  filling. 
The  cavity  should  be  washed  vith  water  and 
dried  with  a  blast  of  air  or  with  an  absorbent, 

!  and  a  dressing  of  foimaldehyde  and  tricresol 
sealed  in  for  several  days.  Pulp  cavities  that 
contain  putrescent  matter  and  have  not  been 
opened  by  caries,  will  not  be  likely  to  give  any 
trouble  if  a  dressing  of  formaldehyde  and  tricresol 
is  sealed  in  tightly;   but  if  the  cavity  has  been 

I  previously  open,  loose  closing  of  the  cavity  may 
be  desirable.  Buckley  believes  that  no  trouble 
will  ensue  if  the  drug  is  hermetically  sealed  in, 
but  this  has  not  been  the  universal  experience  of 
others.  If  one  of  the  gutta-percha  stoppings 
is  used  for  sealing  in  the  dressing,  it  may  be 
punctured  in  one  or  two  places  with  a  broach 
before  it  has  become  hard.     There  should  be 

I  no  attempt  to  remove  the  contents  of  the  oanals 
at  the  first  sitting,  unless  perhaps  a  hooked 
broach  may  catch  a  partially  decomposed  pulp. 
The  contents  of  an  exposed  root-canal  often 
consist  of  a  thick  black  mass  with  a  very  foul 
odour;  the  semi-decaj'e el  mass  of  an  open  canal 

I  does  not  often  have  a  foul  odour. 

At  the  second  sitting  the  rubber-dam  should 
be  applied,  and  the  teeth  isolated  by  it  dis- 
infected; the  sealing  should  be  removed  and 
the  dressing  carefully  examined  for  odour  and 
moisture.  The  contents  of  the  canal  should 
be  removed  and  the  canal  cleansed  and  dried, 
as  described  for  dry  gangrene.  If  the  dressing 
has  been  tightly  sealed  in,  and  there  has  been 
no  pain  since  the  last  sitting,  and  the  periodontal 
membrane  is  not  tender,  and  the  canal  is  dry 
anel  odourless,  and  there  has  been  no  previous 
history  of  the  gum  or  face  being  swollen,  and 
there  is  no  indication  of  a  swelling  or  a  hard 
lump  opposite  the  apex  of  the  root,  then  the 
root-canal    may  be    at    once    filled.      If    these 


473 


conditions  are  not  all  favourable,  a  mild  anti- 
septic or  a  strong  disinfectant  may  be  used  as 
required.  If  moisture  comes  from  the  apex, 
or  there  is  a  history  of  a  swollen  face  or  a  hard 
bean-like  swelling  over  the  apex,  the  putrescent 
pulp  is  probably  complicated  ^nth  a  blind 
abscess.     (See  Chapter  XLII.) 

If  the  pulj)-chamber  has  not  been  opened  and 
there  is  ?io  pain,  the  treatment  is  practically  the 
same  as  in  the  last  case,  except  that  the  dressings 
should  always  be  tightly  sealed  in.  It  should  also 
be  remembered  that  the  contents  of  a  canal  may 
include  organisms  that  only  require  the  presence 
of  oxygen  to  develop  activity  rapidly  and  cause 
an  acute  alveolar  abscess ;  immediate  disinfec- 
tion is  necessary,  as  well  as  great  care  not  to 
force  the  contents  of  the  canal  through  the  apex. 

The  jjutrescent  or  gangrenous  pulp  that  is 
painful  and  not  exposed  is  not  always  easy  to 
diagnose.  The  pain,  like  that  of  an  inflamed 
pulp,  is  relieved  by  cold  and  increased  by  heat. 
The  methods  of  testing  the  vitality  of  the  pulp 
are  described  below. 

The  periodontal  membrane  may  be  infected 
and  irritated  from  a  painful  putrescent  pulp. 
If  an  alveolar  abscess  is  associated  with  moLst 
gangrene  of  the  pulp  there  will  be  a  history  of 
previous  attacks,  or  perhaps  a  hard  lump  over 
the  apex  of  the  root.  The  location  of  the  tooth 
that  is  i^ainful  may  be  discovered  from  the 
history ;  if  the  patient  knows  which  teeth  are 
tilled,  and  how  long  ago  each  one  was  done,  and 
whether  the  pulps  were  devitalized  or  not,  or 
whether  the  filling  was  close  to  the  pulp  or  not, 
the  information  will  be  of  great  assistance ;  a 
cement  filling  is  often  inserted  as  a  test  fiUmg 
in  a  cavity  that  is  close  to  the  pulp. 

The  pulp-chamber  nnist  be  at  once  opened. 
If  th^)eriodontal  membrane  is  tender,  it  is  not 
advisable  to  attempt  to  open  the  chamber 
the  full  size  for  future  treatment ;  it  is  better 
to  be  content  with  a  free  opening  and  drainage 
of  pus.  A  hooked  broach  may  be  passed  into 
the  chamber,  and  an  attempt  made  to  withdraw 
any  fragment  of  the  decayed  or  decaying  pulp ; 
no  attempt  should  be  made  to  enter  the  canals. 
If  the  pus  is  wiped  out,  and  a  dressing  of  form- 
aldehyde and  tricresol  sealed  into  the  cavity  for 
a  few  days,  a  satisfactory  result  will  be  assured. 
If  the  pain  does  not  subside  in  ten  or  fifteen 
minutes  after  the  chamber  is  opened,  and  there 
is  any  reason  to  believe  that  the  periodontal 
membrane  is  infected  and  inflamed,  and  there 
is  danger  of  an  acute  alveolar  abscess  developing, 
a  counter-irritation  of  tincture  of  iodine,  tinc- 
ture of  aconite,  and  chloroform,  in  equal  parts, 
may  be  applied  to  the  gum  opposite  the  root, 
and  the  patient  given  prescriptions  for  a  dose 
of  magnesium  sulphate  or  some  other  suitable 
cathartic,  and  a  five-grain  dose  of  aspirin  to  be 
taken  at  bed-time,  if  the  pain  has  not  subsided. 


Conditions  being  favourable,  the  root-canals 
may  be  thoroughly  cleaned  out  after  three  or 
four  days,  and  a  mUd  dressing,  such  as  Black's 
one-two-three,  oil  of  cloves,  or  creosote,  should 
be  sealed  in  the  canals  for  three  or  four  days 
more,  when  the  canals  may  be  filled. 

Tests  for  the  Vitality  or  Non-vitality  of  a  Pulp. 
(1)  Teeth  «it!i  dead  pulps  are  darker  in 
colour  than  those  with  living  pulps.  If  the  fuU 
rays  of  the  sun  are  allowed  to  fall  upon  the 
anterior  teeth,  while  a  mouth  mirror  is  placed  as 
a  reflecter  on  the  lingual  aspect,  the  full  pinkish 
outline  of  the  living  pulp  can  be  made  out ;  if  it 
is  dead  a  darkish  outline  will  be  shown.  If  the 
room  is  darkened  a  strong  electric  mouth-lamp 
will  show  this  even  better  than  the  sunlight. 

(2)  Normal  live  pulps  will  give  a  shock  when 
extreme  heat  or  cold  is  applied  to  the  tooth. 
All  persons'  teeth  do  not  react  equally  to  heat 
and  cold.  Heat  may  be  applied  by  rolling  up 
a  piece  of  gutta-percha  large  enough  to  cover 
almost  all  of  the  labial  or  buccal  surface  of  the 
tooth  to  be  tested,  heating  it  to  the  blistering 
pomt  over  an  alcohol  lamp  or  Bunsen  flame,  and 
pressing  it  against  the  tooth  and  holding  it  there 
until  some  pam  is  felt,  or  ought  to  be  felt  if  the 
pulj)  is  alive.  The  end  of  a  heavy  steel  mstrument 
handle  may  be  heated  and  touched  against  the 
tooth,  but  this  has  such  a  small  area  of  contact 
that  there  is  not  much  heat  transmitted  to  tooth, 
unless  the  application  can  be  made  to  a  metal 
fillmg.  Hot  air  may  be  applied  from  a  syringe, 
but  it  is  apt  to  strike  more  than  one  tooth,  or 
perhaps  the  gum,  and  thus  make  the  signs  indefi- 
nite. Hot  water  may  be  applied  from  a  syringe, 
but  unless  it  is  confined  to  one  tooth  isolated  by 
the  rubber-dam,  the  signs  are  indefinite. 

Cold  is  best  apijlied  by  placing  a  small  piece 
of  ice  against  the  neck  of  the  tooth.  Cold  air 
or  water  may  be  applied  from  a  sp-inge,  but  the 
same  limitations  obtain  as  in  using  heat.  Cold 
may  also  be  applied  by  means  of  the  ethyl 
chloride  spray  carefully  directed. 

(3)  Periodontal  irritation  is  usually  due  to  an 
extension  of  infection  from  a  septic  pulp.  As 
the  periodontal  membrane  becomes  inflamed 
it  mcreases  in  thickness,  and  presses  the  tooth 
out  of  its  socket,  thus  giving  the  sensation  of  an 
elongated  tooth.  A  tooth  that  at  first  gets 
some  relief  when  pressed  upon,  and  later  becomes 
so  sensitive  to  pressure  that  it  cannot  be  bitten 
upon,  or  even  touched  with  the  tongue,  without 
pain,  probably  has  a  dead  pulp.  In  the  early 
stages  a  slight  tap  will  often  give  a  sensation  of 
pain  when  heavy  pressure  will  not.  Pressure 
from  the  finger  should  be  first  used,  and  then 
very  light  taps  from  a  small  steel  instrument ; 
sensation  thus  elicited  should  be  compared  with 
that  from  a  tooth  with  a  live  pulp.  It  often 
happens  in  molars  that  only  one  root  is  affected  ; 
if  pressure  is  made  against  the  buccal  surface  of 


474 


an  upper  molar  and  pain  is  elicited,  the  chances 
are  that  the  inflammation  is  around  the  lingual 
root,  and  if  pressure  upon  the  lingual  surface 
elicits  pam,  the  buccal  roots  are  the  likely  seat 
of  the  trouble.  Pressure  medially  or  distally 
in  the  lower  molars  may  help  to  distinguish  in 
which  root  the  infection  exists.  It  is  generally 
good  evidence  that  a  j)ulp  is  dead  if  the  peri- 
odontal membrane  is  inflamed,  but  it  is  not 
positive,  because  inflammation  may  be  caused 


(4)  If  the  neck  of  the  suspected  tooth  is  not 
covered  with  gum  tissue  a  sharp  excavator  may 
be  sunk  into  it,  or  an  explorer  scraped  across 
it,  and  any  sensation  noted.  If  the  dentine  is 
exposed  it  may  be  cut  with  a  burr  or  an  ex- 
cavator ;  if  sensation  occurs  the  pulp  is  alive. 
The  operator  must  distinguish  between  the  pain 
and  sensation  caused  by  pressure  on  the 
periodontal  membrane  and  that  produced  by 
cutting  the  dentine.     These  methods  of  testing, 


8 


10 


10 


Fig.  534. — Re-drawn  from  figure  in  Items  oj  Interest. 


by  shock,  too  much  malleting  in  inserting  a 
filling,  separating  teeth,  movement  of  teeth  in 
orthodontics,  extension  of  mflammation  from 
an  mflamed  pulp,  or  local  irritation  around  the 
neck  of  the  tooth  (as  from  projecting  fillings, 
foreign  substances  under  the  gums,  calcific 
deposits  or  pyorrhoea  alveolaris).  It  is  really 
cruel  to  give  a  suspected  tooth  two  or  three 
heavy  blows  with  the  end  of  a  heavy  instrument 
in  order  to  test  the  sensitivity  of  the  periodontal 
membrane ;  pressure  from  the  fuiger,  or  light 
tapping,  gives  more  mformation  and  less  pain. 


and  those  indicated  in  Chapter  XXVI,  and  the 
history  of  the  case,  ought  to  be  sufficient  to 
determine  the  vitality  or  non-vitality  of  the  pulp. 

DEVITALIZATION  AND  MANAGEMENT  OF  PULP 
AND   ROOT-CANALS  OF  DECIDUOUS  TEETH 

(See  Chapter  XXVIII.) 

FILLING   ROOT-CANALS 

The  question  of  filling  root-canale  of  teeth 
has  engaged  the  best  mmds  m  the  dental 
profession  ever  since  it  was  learned  that  pain 


475 


and  discomfort  often  followed  the  death 
of  a  pulp.  Unfortunately,  too  much  atten- 
tion was  given  to  the  kind  of  material  to  be 
used  and  not  enough  to  the  anatomy  and 
pathology  of  the  teeth  and  the  physical  proper- 
ties of  the  materials.  The  use  of  such  materials 
as  metal  wire  or  gold  foU  is  obsolete,  as  they 
cannot  be  made  to  fit  and  fill  root-canals ; 
substances  like  cotton  rope  are  also  out  of  the 
question  at  the  present  time  as  they  cannot 
prevent  the  entrance  of  moisture  and  bacteria. 
It  is  impossible  to  seal  hermetically  a  tube  the 
size  of  a  root-canal  with  any  substance  commonly 
used,  except  oxy-chloride  of  zinc,  which  has 
enough  objectionable  properties  to  make  its 
universal  use  impossible  for  filling  root-canals. 
If  a  perfectly  round  cone-shaped  tube  cannot  be 
hermetically  sealed  when  there  are  no  difficulties 
of  position,  what  chance  is  there  to  seal,  or  even 
accurately  fill,  root-canals  of  the  fineness,  shape, 
and  tortuosity  of  those  found  in  molars  and 
premolars  1  Of  course  it  may  be  said  that  the 
canals  of  upper  incisors  and  canines  are  fairly 
round,  conical,  and  accessible,  but  how  often 
are  pulps  removed  from  these  teeth  in  modern 
practice,  as  compared  with  the  remaining  teeth  ? 
In  the  laboratories  of  the  Royal  College  of 
Dental  Surgeons  (Toronto),  the  %vTiter  has 
examined  critically  over  thirty  thousand  ex- 
perimental root-canal  fillings  made  of  various 
materials  commonly  used,  and  with  an  unaided 
eye  it  could  be  seen  that  not  three  per  cent  of 
the  canals  of  molars  and  premolars  were  opened 
to  the  apex  and  mechanically  filled.  At  the 
first  meeting  of  the  Canadian  Dental  Association 
in  Montreal,  1902,  Jas.  M.  Magee,  St.  John,  New 
Brunswick,  in  a  private  discussion  with  the  late 
Hon.  S.  W.  Mclmiis,  said  he  could  open  to  the 
apex  and  fiU  the  canals  of  eight  molar  roots 
out  of  ten.  Mclnnis  said  he  could  not  fill  five 
out  of  ten.  It  was  agreed  that  ten  molar  teeth 
recently  extracted  should  be  placed  in  plaster 
of  Paris  with  the  crowns  exposed,  and  sent  to 
Magee  to  be  filled,  and  that  Weston  A.  Price 
should  make  a  radiograph  of  the  teeth.  Price's 
remarks  and  the  accompanying  illustration 
(Fig.  534)  show  how  far  an  expert  succeeded 
under  the  most  favourable  circumstances. 

Tooth  No.  1  is  a  lower  molar,  and  the  medial 
root  had  two  canals,  both  of  which  are  drilled 
through  on  the  medial  side  of  the  root ;  and 
where  the  distal  canal  turned  near  the  apex, 
the  root-fOlmg  leaves  it  and  proceeds  into  the 
•wall.     The  apex  is  not  filled  in  either  root. 

No.  2  is  also  a  lower  molar,  and  the  root- 
fUlings  of  both  roots  extend  through  the  apex, 
as  showai  in  A,  B,  C,  and  D. 

No.  3  is  an  upper  molar,  and  fairly  well  filled, 
except  one  root  sho%ra  in  D. 

No.  4  has  not  the  apex  of  either  root  filled. 


No.  5  is  also  a  lower  molar,  and  has  the  root- 
filling  perforating  the  medial  wall,  and  the  apex 
not  fiUed. 

No.  6  is  an  upper  molar,  in  which  neither  of 
the  buccal  roots  is  filled  to  the  apex  (one  of  the 
best,  however). 

No.  7  is  an  upper  molar,  in  which  the  medial 
root  is  not  fiUed  to  the  apex. 

No.  8  is  a  lower  molar  with  small  canals, 
neither  of  which  is  fiUed  to  the  apex. 

No.  9  is  an  upper  molar,  well  filled. 

No.  10  is  a  lower  molar ;  the  medial  root  has 
two  canals,  but  both  are  fiUed,  and  the  canals 
have  been  opened  to  the  apex ;  the  root-filling 
buckled  outside  the  root.  The  distal  root  is 
not  filled  at  the  apex,  though  nearly  to  it. 

From  a  mechanical  standpoint  nearly  all  of 
these  roots  are  far  from  being  well  filled  to  the 
apex,  though  they  are  much  better  than  the 
average  found  in  the  mouth. 

So  much  for  the  mechanical  possibilities. 
Now  what  of  the  capability  of  any  of  the  root- 
canal  fillings  acting  as  a  barrier  to  either  bacteria 
or  moisture  when  the  canal  is  mechanically 
filled  ?  Below  are  given  a  few  sets  of  experi- 
ments selected  from  over  a  thousand  made  in 
the  Royal  College  of  Dental  Surgeons  (Toronto). 

Series  A 

Ten  tubes  made  as  in  Fig.  535  were  filled  with 
bouiUon,  their  mouths  were  plugged  with  cotton- 
wool, and  they  were  sterUized  for  three 
consecutive  days.  The  plug  of  each  was 
then  removed  from  the  neck,  which  was 
moistened  with  eucalyptus ;  chloro- 
percha  was  pumped  into  the  constric- 
tion, and  a  gutta-percha  cone  was  made 
to  fit  and  forced  home,  without  using 
much  heat,  and  the  packing  was  con-  u 
tinned  until  the  gutta-percha  was  per-  !' 
fectly  cool.  The  remaining  portion  of 
each  tube  was  filled  with  cement.  About 
twenty  mmutes  after  the  tubes  were 
filled,  nine  were  placed  on  their  sides  in 
a  beaker  of  saliva,  one  being  retained  as 
a  control ;  the  tubes  were  completely 
covered.  The  beaker  was  then  placed 
in  the  incubator,  and  tests  made  of  the 
contents  of  the  tubes  showed  the  follow-  pio.  535. 
ing  results — 

In  1  day  1  tested ;  not  infected. 

In  2  days  1  tested ;  not  infected. 

In  3  days  1  tested  ;   not  infected. 

In  4  days  1  tested ;  infected. 

In  5  days  I  tested  ;   not  infected. 

In  7  days  1  tested  ;  not  infected. 

In  9  days  1  tested ;  not  uifected. 

In  14  days  1  tested  ;   infected. 

In  17  days  1  tested  ;   infected. 

In  17  days  control  tested  ;  not  infected. 


476 


Series  A  having  exhibited  a  protective  power 
for  root-canal  and  crown  fillings  for  only  fourteen 
days,  it  was  determined  to  insert  some  amalgam 
fillings,  and  also  some  gutta-percha  root-fillings 
covered  with  a  layer  of  oxy-chloride  of  zinc, 
using  the  greatest  possible  care  in  their  insertion, 
both  as  regards  mechanical  correctness  and  from 
a  bacteriological  standpoint. 

Series  B 
Heavy    glass    tubes,    two    mches   long    and 
\  of  an  inch  bore,  were  drawn  to  a  fine  neck 
about  I  of  an  inch  from  the  end  ;  the  terminal 
^  of  an  inch  was  made  into  a  cylindrical  bowl, 
with  a  solid  rim  and  a  flat  base,  the  ' 
centre  of  the  base  having  a  fine  hole 
leading  to  the  tube  below  (Fig.  536). 
The   inside   walls  of  the   bowl   were  i 
ground   with  a  stone  so   that  they  i 
became  rough,  similar  to  the  walls  of  | 
a  recently  prepared  cavity  in  a  tooth. 
The  bowls  were  plugged  with  cotton 
^^■ool  and  sterilized  in  dry  air  at  160°  C. 
for  one  hour,  and  then  filled  almost 
to  the  constriction  with  bouillon.   The 
plugs  having  been  replaced,  the  tubes 
i        were    sterilized    in    live    steam    for 
twenty  minutes  on  three  consecutive 
days. 

Alloy,  mercury,  mortar  and  pestle, 
and  all  instruments  used  in  inserting 
Fig  530  fillings,  were  sterilized  in  dry  air  at 
160°  C.  for  one  hour;  the  sterilizer 
was  then  allowed  to  cool  to  37°  C.  Thus, 
the  tubes,  the  mstruments,  the  filling-materials, 
and  the  saliva,  were  all  at  the  same  tem- 
perature,—37°  C.  The  filling  materials  were 
mixed,  and  placed  in  the  bowls  of  the  tubes  in 
the  sterilizer.  In  this  way  there  could  be  no 
possible  chance  of  error  by  an  unequal  ex- 
pansion or  contraction  of  the  glass  or  the  filling- 
materials  on  account  of  changes  of  temperature. 
Within  ten  mmutes  of  the  bowl  being  filled  with 
the  amalgam  the  tubes  were  immersed  in  the 
beaker  of  saliva.  The  beaker  was  then  placed 
in  the  mcubator,  which  was  maintained  at  a 
uniform  temperature,  37°  C.  In  all,  thirteen 
tubes  were  filled,  of  which  ten  were  put  in  saliva, 
and  three  controls  were  put  through  all  pro- 
ces.ses,  except  being  placed  in  the  saliva.  Some 
of  the  amalgam  mixed  was  embedded  in  agar 
and  put  in  the  incubator.  In  no  case  were  the 
materials,  instnunent  points,  or  contents  of  the 
tubes,  touched  with  the  hands ;  as  far  as 
possible  every  source  of  infection  was  guarded 
against. 

In  7  days  2  tubes  tested  ; — 1  control 
and    1    from   saliva ;    neither   in- 
fected. 
In  16  days  1  tested  ;  not  infected. 
In  39  days  1  tested  ;  not  infected. 


'     ] 


In  47  days  1  tested ;   not  infected. 

In  52  days  1  tested ;    bouillon  cloudy, 

but  no  growth  on  agar. 
In  61  days  1  tested ;  not  infected. 
In  66  days  1  tested  ;   infected. 
In  73  days  1  tested  ;   infected. 

Series  C 

The  same  heavy  tubes  were  used  in  these 
exjjeriments,  but  having  the  necks 
drawn  out  much  longer  (Fig.  537), 
so  as  to  make  a  fuie  root-canal. 
All  -were  filled  under  the  same  con- 
ditions of  care,  etc.,  as  the  jweceding  ; 
the  canals  were  lubricated  \\ith 
chloro-percha,  and  gutta-percha  cones 
forced  home,  little  heat  and  good 
pressure  being  used.  (There  is  serious 
objection  to  heating  gutta-percha 
very  much  when  filUng  a  canal ;  it 
greatly  contracts  on  cooling.)  About 
half  an  hour  after  the  canals  were 
filled  the  bowl  was  filled  with  cement. 
Eleven  tubes  were  filled,  and  as  soon 
as  the  cement  was  set  all  were  placed 
in  the  saliva. 

In  8  days  1  tube  tested  ;  not    piG.  537. 

infected. 
In  13  days  1  tube  tested  ;   not  certain 

but  probably  infected. 
In  20  days  1  tube  tested  ;  infected. 
In  28  days  1  tube  tested  ;  infected. 
In  32  days  1  tube  tested ;   infected. 

Series  D 

In  this  series  the  canals  were  filled  as  above, 
and  over  the  filling  was  placed  a  thm  layer  of 
oxy-chloride  of  zmc,  and  over  that  the  same 
cement  as  in  previous  series. 

Seven  tubes  were  filled  and  all  were  placed  in 
saliva. 

In  6  days  1  tested  ;   not  hifected. 

In  13  days  1  tested;   not  infected. 

In  20  days  1  tested ;  not  mfected. 

In  28  days  1  tested ;  not  infected. 

In  33  days  1  tested ;  not  infected. 

Series  E 

In  this  series  the  canals  were  as  well  filled 
with  gutta-percha  as  possible ;  the  tubes  were 
slightly  warmed,  no  lubricant  was  used,  and  the 
cavity  was  not  filled  with  cement. 

Five  tubes  were  filled  and  put  in  saliva. 

In  24  hours  5  were  tested,  and  2  were  infected. 

Series  E  shows  the  permeability  of  gutta- 
percha unprotected  by  oxy-chloride. 

The  above  experiments  are  a  corroboration 
of  those  previously  made  in  a  purely  mechanical 


477 


way,  which  pointed  directly  to  what  was  sus- 
pected at  that  time,  and  to  what  has  been  shown 
by  more  recent  mvestigation.  The  ordinary  root- 
canal  filling  is  not  a  harrier  to  either  moisture  or 
bacteria.  The  wTiter,  wlien  malving  the  experi- 
ments, did  not  cheani  of  tlie  infection  of  a  root- 
canal  from  the  oral  cavity,  but  was  directing 
attention  to  the  possibility  of  closing  the  apical 
end  of  the  root-canal  only.  To  quote  from  the 
paper  in  question  :  '"  If  a  root-canal  ought  to  be 
filled  there  must  be  some  reason  for  it.  The  best 
and  only  reason  for  fillmg  a  root-canal  is  to  keep 
something  out  of  it  that  is  undesirable.  That 
undeshable  something  is  most  likely  moisture 
or  granulation  tissue,  or  both,  with  a  probable 
pyogenic  infection.  It  is  fair  to  assume  that 
a  filling-material  that  will  prevent  the  passage 
of  moisture  will  prevent  the  passage  of  bacteria 
and  granulation  tissue.  This  being  granted, 
the  relative  merits  of  absorbent  cotton-wool, 
raw  cotton,  gutta-percha,  and  the  cements,  as 
barriers  to  the  passage  of  moisture,  and  hence 
the  passage  of  bacteria,  can  be  seen  from  the 
following  experiments.  It  must  be  borne  m 
mmd  that  these  experiments  do  not  relate  in  any 
way  to  the  solubility,  destructibility,  density,  or 
irritating  qualities  of   the  materials  used." 

Glass  tubes,  about  two  inches  long  and  ^ 
of  an  inch  bore,  were  drawn  to  a  fine 
point  at  one  end,  \\hile  the  other  end  remamed 
its  orighial  size.  In  this  way  a  cone  was  made 
about  J  of  an  inch  long,  and  resembling 
the  root-canal  of  a  tooth.  Li  all  cases  these 
cones  were  opened  clear  through.  After  being 
fiUed  with  the  root-canal  filling-material,  thek 
small  ends  were  immersed  in  a  red-coloured 
solution.  This  was  accomplished  by  passing 
the  tubes  through  holes  cut  in  a  piece  of  card- 
board placed  over  a  shallow  pan  containing 
the  red  solution.  The  tubes  were  held  in  an 
upright  position,  and  only  their  small  ends  were 
below  the  surface  of  the  solution. 

Below  is  a  tabulated  form  of  results  of  ex- 
periments, arranged  in  the  order  in  which  the 
various  fillings  acted  as  barriers  to  moisture. 

Series  F 


Material. 

Tubes. 

Hours. 
Time. 

Col- 
oured. 

Not 
Col- 
oured 

Chloro  -  percha      and 

gutta-pereha    points 

10 

48 

3 

7 

Gutta-percha 

13 

48 

6 

7 

Oxy-chloride  of  zinc    . 

13 

48 

11 

2 

Cotton-wool  and 

chloro-percha 

10 

48 

8 

2 

Raw  cotton 

22 

48 

22 

— 

Absorbent  cotton-wool 

7 

24 

7 

— 

Oxy-phosphate  of  zinc. 

12 

72 

12 

— 

Oxy-phosphate  of  zinc. 

13 

48 

13 

— 

Thus   it   would   appear   that    if   there    were 
moisture  at  the  end  of  a  root-canal,  practically 


none  of  the  above  materials  would  prevent  its 
passage  mto  the  tooth  cavity. 

It  may  be  safely  stated  that  oxy-phosphate 
cements,  gutta-percha,  cotton-wool,  or  any 
combination  of  these  with  each  other  or  with 
any  other  non-disinfecting  materials,  will  not 
prevent  the  passage  of  moisture  or  bacteria. 
Oxy-chloride  of  zinc  will  prevent  passage  of 
bacteria  for  at  least  sixty  days,  as  sliouai  in 
Series  B.  Some  amalgams,  if  properly  mixed 
and  mserted,  will  resist  bacteria  for  two  months, 
and  others  will  not  resist  bacteria  for  three 
hours,  no  matter  how  mixed  or  inserted.  After 
testing  ten  or  twelve  cements  of  different 
makes  the  writer  concluded  that  they  all  leak ; 
those  that  do  not  shruik  allow  passage  to  take 
place  through  the  mass.  The  only  difference 
is  that  those  that  shrink  leak  sooner  than  those 
that  do  not.  Only  a  few  amalgams  have  been 
tested,  but  it  is  quite  likely  that  only  those  leak 
that  contract  or  fiow  badly. 

In  the  face  of  the  fact  that  very  few  root- 
canals  are  even  mechanically  well  filled,  and  that 
few  if  any  root-canal  fillings  will  act  as  a  bar- 
rier to  bacteria,  roots  filled  with  asbestos, 
silk  fibre,  vaselme,  wax,  oxy-sulphate  of  zinc, 
oxy-phosphate  of  zinc,  oxide  of  zinc,  oil  of 
cloves,  creosote,  aristol,  and  campho-phenicjue, 
metallic  whes,  gold  foil,  amalgam,  and  a  host 
of  other  substances,  remain  comfortable  for  the 
balance  of  the  patient's  life.  There  are  myriads 
of  teeth  in  which  tlie  pulps  have  died  and  not 
been  treated,  and  yet  have  given  no  trouble  to 
the  patient. 

To  sum  up  all  that  has  been  said  :  it  is  almost 
impossible  to  reach  the  apex  of  even  the 
majority  of  root-canals,  and  even  if  they  are 
reached  there  is  no  suitable  material  that  will 
permanently  prevent  infection  about  the  apex. 
But  success  is  in  proportion  to  the  thorough- 
ness with  which  the  pulp  is  removed  and  the 
root-canal  antiseptically  and  mechanically 
filled ;  in  other  words,  it  depends  upon  the 
removal  of  all  the  conditions  favourable  to 
the  growth  of  bacteria.  The  possibility  of  the 
tissues  about  the  apex  never  becommg  infected 
depends  fuially  upon  the  resistance  of  the 
individual  to  infection.  When  the  general 
resistance  is  low,  and  there  are  present  enough 
of  sufficiently  virulent  organisms,  then  infection 
will  occur.  Organisms  wUl  only  develop  when 
both  local  and  general  conditions  are  favourable. 
If  a  root-canal  is  open  at  the  apex  and  partly 
filled  with  a  dead  pulp,  or  if  the  root-filling  is 
porous  or  leaks,  or  if  the  tissues  at  the  apex  have 
been  weakened  in  resistance  by  mechanical  or 
chemical  uTitation,  favourable  conditions  exist 
for  the  growth  of  bacteria.  The  presence  of 
organic  matter  (such  as  dead  pulp),  or  local 
irritation,  or  space  into  which  liquid  exudate 
from  wounded  tissues  may  pass,  or  organic  or 


478 


destructible  root-filliiigs,  offers  favourable  con- 
ditions for  the  growth  of  organisms.  The 
organisms  may  come  from  the  general  circula- 
tion, or  from  the  crown  of  the  tooth  through 
fiUmg  and  canal,  or  may  have  been  left  in  the 
canal  at  the  time  of  the  filling.  The  two  im- 
portant considerations  in  fiUmg  a  canal  are, 
firstly,  to  mamtain  a  sterile  condition,  and, 
secondly  (the  more  important),  to  leave  no 
condition  that  will,  now  or  hereafter,  favour 
the  growth  of  pathogenic  bacteria. 

Properties  of  a  Perfect  Root-Canal  Filling-Material 

1.  It   should   be   liquid   during   insertion,  so 

that  it  may  reach  every  crevice  in  the 
canal . 

2.  It  should  not  be  capable  of  irritating  the 

livmg  tissues. 

3.  It     should     become    solid    shortly     after 

insertion. 

4.  It  should  be  insoluble  in  the  fluids  of  the 

body. 

5.  It    should    be    impermeable     by    either 

bacteria  or  moisture. 

6.  It  should  hermetically  seal  a  cavity. 

7.  It  should  be  aseptic,  or  perhaps  have  anti- 

septic properties. 

8.  It  should  be  of  a  colour  different  from  the 

tooth  tissue,  and    be  capable    of    easy 
removal. 

Root-Canal  Filling-Materials. — There  are  two 
general  classes  in  common  use  :  mechanical, 
and  antiseptic  or  disinfectant.  Combinations 
of  the  two  are  sometimes  used. 

Mechanical  Root-Canal  Filling-Materials — 

Gutta-percha. 

Oxy -chloride  of  zinc. 

Oxy-phosphate  of  zinc. 

Oxy-sulphate  of  zinc. 

Oxy-phosphate  of  copper. 

Wax. 

Paraffin. 

Antiseptic  or  Disinfectant  Root-Canal  Filling- 
Materials — 

Oxide  of  zinc.  Paraform. 

Alum.  Iodoform. 

Tannic  acid.  Aristol. 
Thymol. 

One  of  these  powders,  or  more  than  one 
mixed  together,  may  be  made  into  a  suitable 
paste  for  insertion  in  the  canal  by  triturating 
with  one  or  more  of  the  followmg  liquids — 


Creosote. 
Oil  of  cloves. 
Tricresol. 
Formaldehyde. 


Phenol. 

Campho-phenique . 
Glycerine. 


A  favourite  preparation  is  alum,  tannic  acid, 
and  thymol,  equal  parts,  made  into  a  paste  with 
glycerme. 

Combination  Root-Canal  Filling -Materials — 

Chloro-percha  and  gutta-percha  points. 

Chloro-percha  combined  with  metallic  points. 

Antiseptic  pastes  with  gutta-percha  points. 

Gutta-percha  and  oxy-chloride  of  zmc. 

Chloro-percha  and  oxy-chloride  of  zinc. 

Salol. 

Canada  balsam. 

Balsam  of  Peru. 

(Iodine  and  mercurial  combinations  are 
unsatisfactory  because  of  the  dangers  of  dis- 
coloration of  the  tooth.) 

How  to  make  Chloro-jxrcha  for  Lubricating 
Root-Canals. — Take  a  jar  that  will  hold  about 
two  to  four  oiuices,  and  fill  it  about  three-quar- 
ters with  jjink  base-plate  gutta-percha  cut  into 
squares  or  strips  small  enough  to  settle  well  into 
the  bottom  of  the  jar.  Pour  over  this  enough 
chloroform  to  cover  the  gutta-percha  fully. 
Allow  to  stand  for  a  few  hours,  closely  covered. 
Shake  well,  and  much  sediment  will  fall  to  the 
bottom  ;  gutta-perchas  now  used  are  loaded  with 
oxide  of  zmc  and  other  materials  that  are  not 
suitable  ingredients  of  chloro-percha  for  fiUmg 
root-canals.  To  remove  these,  stram  through 
cheese  cloth  into  a  wide -mouthed  bottle  with 
an  outside  cover,  which  is  not  so  likely  to  become 
smeared  as  a  cork  that  fits  uiside.  Finally, 
ground  thymol  crystals  may  be  dissolved  in 
chloroform  and  added,  or  may  be  thrown  into 
the  liquid  undissolved — use  about  two  or  three 
drachms  of  thymol  to  an  ounce  of  gutta-percha. 
As  the  chloroform  evaporates  add  oil  of  cajuput 
to  keep  it  liquid.  After  some  months  all  the 
chloroform  will  have  evaporated,  and  the  gutta- 
percha will  be  held  m  solution  by  the  oU  of 
cajuput.  This  chloro-percha  will  be  ropy  and 
tenacious — not  so  short-grained  as  that  made 
from  base-i^late  gutta-percha  unstrained. 

Selection  of  a  Root-Canal  Filling-Material. 
Among  all  the  root-filling  materials  mentioned, 
and  scores  of  others  that  have  been  used,  but 
should  never  again  be  mentioned  except  as  a 
matter  of  history,  there  is  not  one  that  fulfils 
the  requirements  set  forth  in  a  former  paragraph. 
The  best  that  can  be  done  is  to  select  the  one, 
or  the  combination,  that  will  most  nearly  suit 
the  conditions  present.  If  all  root-canals  were 
of  like  form  and  equally  accessible,  and  all  the 
pulp  could  always  be  removed,  and  all  were  in 
an  equal  state  of  asepsis,  and  all  the  apices  were 
of  equal  size,  and  all  the  tissues  at  the  apex 
were  of  equal  resistance, — then  there  might  be 
selected  a  universal  root-canal  filling.  The 
very  difficulty  of  making  a  selection  of  a  proper 
filling  material  for  each  case  makes  this  depart- 


479 


ment  of  dentistry  interesting.  Most  of  the 
failures  in  the  management  of  root-canals  can 
be  traced  to  errors  of  judgement,  or  want  of 
knowledge  of  the  conditions  present.  The 
experiments  that  are  described  on  pp.  475-7 
indicate  that  no  matter  \\  hat  root-fillmg  material 
is  used,  the  outer  part  of  the  root-canal  and  the 
pulp-chamber  should  be  filled  with  oxy-chloride 
of  zmc. 

Eoot-canals,  of  normal  size  and  accessibility, 
in  which  the  pulp  has  been  recently  devitalized 
by  arsenic  or  cocaine,  and  from  which  the  pulp 
has  been  completely  removed  under  aseptic 
precautions,  and  in  which  no  moisture  or  irrita- 
tion exists  at  the  apex  (or  in  the  periodontal 
membrane),  should  be  fiUed  with  a  mechanical 
root-canal  filling  or  an  antiseptic-mechanical 
filling.  For  this  purpose  there  is  nothmg  that 
so  nearly  fulfils  the  requirements  as  chloro- 
percha,  made  as  previously  described,  to  fill  the 
apex,  with  a  gutta-percha  cone  of  suitable  size 
pressed  into  it ;  the  whole  should  be  covered  with 
oxy-chloride  of  zmc. 

Technique. — The  filling  of  root-canals  with 
gutta-percha  and  oxy-chloride  of  zmc  is  exactmg 
in  detail. 

(1)  The  consistency  of  the  chloro-percha  must 
be  such  that  it  can  be  carried  to  the  canal  with 
a  smooth  broach ;  it  should  not  be  so  liquid  as 
to  drop  from  the  broach,  nor  should  it  roll  up 
upon  it  \\iien  rubbed  against  the  walls  of  the 
canal.  The  fibre  should  be  long,  and  should 
draw  out  as  the  temperature  rises. 

(2)  The  canal  should  be  perfectly  dried,  and 
the  walls  then  moistened  with  oil  of  cajuput  or 
eucalyptol.  This  may  be  done  by  carrying  an 
excess  to  the  cavity  and  pumpmg  into  the  canals, 
and  then  wiping  the  excess  out  with  «isj)s  of 
cotton-wool  \\ound  on  a  broach  and  passed  into 
the  canal ;  or  by  moistening  in  the  oil  the 
cotton-wool  wound  upon  the  broach,  and 
passmg  this  wp  the  canal.  The  object  of 
moistening  the  walls  of  a  canal  with  a  solvent 
of  gutta-percha  is  to  mduce  it  to  pass  into  the 
line  extremity  of  the  canal.  The  lubricant 
serves  the  same  purpose  as  the  moisture  in  an 
investmg  flask  where  plaster  of  Paris  is  used. 
It  is  next  to  impossible  to  fiU  fine  dry  canals 
with  chloro-percha  by  pumping  it  in  with  a 
broach  ;   they  might  be  filled  under  pressure. 

(3)  The  canal  havmg  been  moistened,  the 
largest  smooth  broach  that  will  comfortably 
enter  the  canal  should  be  dipped  into  the 
chloro-percha  and  carried  to  the  canal  and 
pumped  in  and  out ;  the  broach  may  need  to  be 
dipped  into  the  chloro-percha  several  times 
before  enough  will  be  carried  to  the  canal  to  fill 
it.  The  pumpmg  should  be  discontinued  if  the 
patient  perceives  any  sensation,  \\hich  should 
be  constantly  inquired  for,  as  otherwise  some 
patients  might  imagine  the  irritation  caused  by 


pumping  chloro-percha  through  the  end  of  a 
root  to  be  a  necessary  part  of  the  operation. 
There  may  not  be  any  sensation  at  all,  but  the 
operator  should  satisfy  himself  that  the  solution 
has  gone  well  to  the  apex. 

(4)  A  gutta-percha  cone  of  suitable  size  and 
length  is  selected  and  grasped  with  a  pair  of 
dressing  forceps  and  directed 
to  the  canal  and  carried  as 
far  as  possible.  If  no  sensa- 
tion is  felt,  and  there  is  some 
doubt  whether  the  point  has 
reached  the  apex,  a  flat-ended 
root-canal  plugger  (see  Fig. 
538)  should  be  gently  pressed 
upon  it.  It  is  advisable  to 
select  a  cone  large  enough  to 
fill  the  whole  canal,  but  if  this 
has  not  been  done,  or  the 
canal  is  of  such  a  shape  that 
a  cone  will  not  fit  it,  several 
cones  may  be  packed  into  the 
canal.  It  is  not  advisable  to 
heat  the  gutta-  percha  cone  or 
dip  it  mto  a  solvent  before 
placmg  it  in  the  canal ;  the 
cone  should  be  kept  as  rigid 
as  possible,  so  that  it  may  be 
forced  to  the  apex.  If  there 
is  any  reason  to  believe  that 
the  cone  has  not  gone  to  the 
apex,  the  root-canal  plugger 
may  be  heated,  and  dipped  in 
vaselme  or  an  essential  oil  to 
keep  the  gutta-percha  from 
adhermg,  and  pressed  fii'mly 
upon  the  contents  of  the 
canal.  This  will  force  the 
gutta-percha  to  the  apex,  but 
it  will  just  as  certainly  expand 
the  gutta-percha  ui  the  outer 
part  of  the  canal,  which  ^\  ill 
afterwards  contract  and  leave 
spaces;  it  will  also  poke  the 
gutta-percha  full  of  holes, 
which  it  is  impossible  to  fiU. 
The  object  is  to  fill  the  canal 
as  tightly  as  possible  with 
gutta-percha ;  consequently, 
there  should  be  as  little  as  Fia.  538 
possible  of  the  solvent  left  in 
the  chloro-percha  when  the 
operation  is  completed.  The 
filling  should  be  cool  and  without  porosity 
when  the  final  pressure  is  relieved.  The  rule 
should  be  not  to  warm  the  gutta-percha  more 
than  is  absolutely  necessary.  (Make  a  few 
experimental  fillings  m  a  conical  glass  tube,  and 
compare  the  results  of  dried  and  lubricated 
walls  and  cool  cones  packed  to  place,  with 
heated  cones  packed  with  root-canal  pluggers.) 


Root- 
Canal  Pluggers. 
(Dental  Manujac- 
turing  Co.,  Ltd.) 


480 


(5)  After  a  little  experience  there  will  not  be 
enough  gutta-percha  used  to  fill  the  outer  part 
of  the  root-canal  or  the  pulp-chamber ;  if  there 
is  any  excess  of  chloro-percha  remainmg  it 
should  be  removed.  Oxy-chloride  of  zhic 
should  be  mixed  to  such  a  consistency  that  it 
can  be  easily  carried  into  the  canal  and  pulp- 
chamber  and  firmly  packed.  The  primary 
settmg  of  some  examples  of  oxy-chloride  of 
zinc  is  often  very  annoying ;  it  hardens  to  the 
point  of  crumbling  almost  as  soon  as  it  is  mixed, 
and  then  takes  several  hours  to  become  finally 
hard.  The  samples  with  a  thick  syrupy  liquid 
are  more  tenacious  than  those  with  a  thin 
liquid,  and  seem  to  have  a  primary  and  second- 
ary setting  nearer  together  in  point  of  time.  If 
the  mass  sets  too  quickly,  a  few  drops  of  saturated 
solution  of  boracic  acid  in  the  bottle  of  liquid 
will  correct  this.  If  need  be,  the  oxy-chloride 
may  be  formed  so  as  to  act  as  a  seat  for  the 
permanent  filling. 

Merits  and  Demerits  of  the  Filling. — Chloro- 
percha  made  as  described  is  as  permanently 
antiseptic,  contracts  as  little,  and  causes  as 
little  irritation  to  the  tissues,-  as  any  material 
(singly  or  in  combination)  known.  It  is  capable 
of  being  carried  quite  to  the  end  of  the  root 
without  wounding  the  sensitive  tissues.  The 
cones  that  follow  are  flexible,  yet  sufficiently 
rigid,  and  \\hen  being  carried  to  place  squeeze 
out  the  excess  of  chloro-percha,  thus  filling  the 
canal  as  far  as  possible  with  a  solid.  Even  if  the 
cone  does  reach  beyond  the  apex,  it  is  immersed 
in  a  solvent,  which  will  round  the  point  and 
I^revent  u-ritation ;  gutta-percha  itself  is  a 
non-irritant.  Gutta-percha,  however,  is  some- 
what porous  and  may  leak ;  it  is  therefore 
important  to  leave  as  little  space  as  possible  for 
moisture,  and  to  make  the  canal  as  mechanically 
full  as  can  be.  The  oxy-chloride  of  zmc  in  the 
outer  part  of  the  canal  acts  as  a  barrier  to 
infection  of  the  canal  from  the  crown.  The 
colour  of  the  chloro-iDercha  is  pink,  which  is  of 
sufficient  contrast  to  make  it  easy  to  follow  if  it 
has  to  be  removed ;  tliLs  can  be  easily  done 
either  with  a  reamer,  or  by  softening  it  with 
heat  or  a  solvent ;  oil  of  cajuput  sealed  into  the 
cavity  for  a  few  hours  will  soften  it,  so  that  it 
may  be  readily  removed  with  a  Kerr  or  Do\vnie 
reamer.     Chloroform  Ls  the  most  rapid  solvent. 

The  objection  to  a  complete  root-canal  filling 
of  oxy-chloride  of  zinc  is  its  irritating  properties  ; 
it  may  be  safely  said  that  if  there  is  no  irritation 
from  an  o.xy-chloride  of  zinc  root-fiUmg,  either 
the  apex  is  not  open  or  the  canal  is  not  filled. 
The  irritation  Ls  often  severe,  and  sufficient  to 
make  a  permanently  lame  tooth.  There  is  also 
the  insurmountable  difficulty  of  removing  an 
oxy-chloride  root-fiUing ;  it  is  the  same  colour 
as  the  dentine  of  the  tooth,  and  so  hard  that  a 
drill  or  reamer  will  not  follow  it.     In  the  com-  I 


bination  of  oxy-chloride  of  zinc  and  gutta- 
percha all  the  vu'tues  of  each  are  utilized  and 
tew  of  their  faults. 

Fine  Root-Canals  in  which  all  the  pulp  has 
been  devitalized  by  arsenic,  or  pressure  an- 
aesthesia, and  from  \\hich  all  has  been  success- 
fully removed,  so  that  there  is  neither  pam 
iior  tenderness  connected  with  the  tooth,  nor 
moisture  in  the  canals,  may  be  filled  at  once  by 
the  same  method  as  that  just  described,  with 
certain  modifications.  It  may  be  found  im- 
l^ossible  to  jjump  the  chloro-percha  to  the 
apex  ^^  itli  a  broach ;  in  that  case  the  pulp- 
chamber  and  as  much  of  the  canal  as  convenient 
may  be  filled  with  chloro-percha,  and  a  piece  of 
vulcaniznig  rubber  sufficiently  large  to  confine 
the  chloro-percha  placed  over  it ;  pressure  is 
then  brought  to  bear  upon  the  rubber  with 
as  large  an  instrument  as  will  enter  the  cavity. 
Pressure  should  be  applied  gently,  to  give  time 
for  the  air  in  the  canal  to  escape  through  the 
tissue,  and  allow  the  chloro-percha  to  reach  the 
apex.  In  many  of  these  cases  it  is  impossible 
to  get  a  gutta-percha  cone  to  enter  the  canal. 
The  excess  of  chloro-percha  should  be  wiped 
out,  ■  and  the  oxy-chloride  squeezed  mto  the 
canal  as  far  as  possible.  It  often  happens  in  an 
upper  molar  that  the  lingual  root-canal  can  be 
readily  filled,  but  that  the  buccal  roots  are  so 
fine  that  access  is  difficult,  and  gutta-percha 
cones  cannot  be  used.  Though  it  is  convenient 
to  pump  the  chloro-percha  into  all  three  roots 
at  the  same  time,  this  should  not  be  done ;  the 
large  root  should  be  completely  filled  first,  and 
the  chloro-jjercha  then  placed  in  the  pulp- 
chamber  and  pressed  into  the  canals  with  rubber 
as  before  described.  If  pressure  were  used 
when  all  three  canals  were  open,  the  large  one 
would  be  overfilled,  or  the  small  ones  would 
not  be  sufficiently  filled. 

Fine  root-canals  in  which  all  the  pulp  recently 
devitalized  has  not  been  removed,  although  a 
careful  attempt  has  been  made,  should  be  treated 
so  as  to  preserve  the  remaming  pulp  tissue  in 
such  a  condition  that  micro-organisms  will  not 
grow  in  it.  Dryness  and  antiseptics  are  the 
chief  hoiJe.  The  small  quantity  of  material, 
and  the  fineness  of  the  apex,  are  favourable 
factors.  Other  thmgs  being  equal,  the  perman- 
ency of  a  disinfectant  depends  upon  the  slowness 
with  which  it  loses  its  disinfecting  power.  Dis- 
infectants are  useful  as  such  in  proportion  to 
their  power  to  destroy  organic  life  ;  if  they  wOl 
destroy  vegetable  life,  they  will  destroy  cellular 
life  as  found  in  animal  tissue.  Hence  dis- 
infeetant.s  are  irritating,  and  if  used  in  a  root- 
canal  at  all,  their  irritating  power  must  be  so 
masked,  or  allowed  to  come  in  contact  with  the 
living  tissue  in  such  mmute  quantities,  that 
there  is  no  poisonous  action.  To  this  end, 
antiseptics  of  the  most  lasting  character  should 


481 


be  used  iii  combination  with  some  substance 
that  will  not  allow  a  rapid  loss  of  the  di'ug's 
antiseptic  power.  There  have  been  many 
methods  of  mummification  of  the  dental  pulp 
recommended.  Drugs  that  abstract  moisture, 
and  are  of  the  aromatic  variety,  have  been 
most  in  favour,  e.  g.  alum,  thymol,  tannic  acid, 
and  glycerine  to  make  a  paste  ;  oxide  of  zinc, 
thymol,  and  creosote  to  make  a  paste ;  or 
oxide  of  zinc,  thymol,  tricresol,  and  formalde- 
hyde. (Formaldehyde  is  so  u-ritating  that  a 
good  deal  of  the  solid  should  be  mixed  with 
it  to  prevent  its  rapid  dissipation.)  Oxide 
of  zinc  and  oil  of  cloves  have  also  been  much 
used.  If  there  is  any  difficulty  m  gettmg  the 
solution  well  mto  the  canal  (and  there  usually 
is),  a  non-uritant  antiseptic  should  be  used, 
because  when  rubber  pressure  is  made  there  is 
no  certainty  that  a  little  of  the  drug  may  not  be 
forced  through  the  apex.  As  much  of  the  paste 
as  possible  should  be  worked  into  the  canal, 
and  pressure  applied  if  necessary,  and  then  a 
gutta-percha  cone  forced  as  far  up  the  canal  as 
possible,  and  a  covermg  of  oxy-chloride  of  zinc 
inserted.  Balsam  of  Peru  has  been  recently 
recommended  for  filling  fine  canals ;  it  is  an 
aromatic  thick  brown  liquid  easily  forced  into 
fine  canals. 

Root-Canals  that  have  been  the  Seat  of  Infectious 
Matter  for  a  Long  Period  should  be  filled  with  an 
antiseptic  root-fillmg  material ;  the  same  rule 
applies  when  there  is  some  doubt  about  the 
state  of  the  tissues  beyond  the  apex.  The  opinion 
has  been  expressed  that  a  root-canal  once  the 
seat  of  a  prolonged  mfection  can  never  be  wholly 
sterilized.  There  would  seem  to  be  some  evi- 
dence in  practice  to  substantiate  this  view  : 
a  tooth  that  has  once  been  the  seat  of  a  violent 
infection  is  prone  to  another  attack ;  even  if 
the  second  acute  attack  does  not  occur,  the 
periodontal  membrane  seems  to  lose  its  vitality 
after  a  number  of  years,  and  the  tooth  is  ever 
afterwards  lame.  If  an  acute  alveolar  abscess 
has  occurred  without  much  involvement  of  the 
periodontal  membrane,  as  occasionally  happens, 
the  future  of  the  tooth  is  more  hopeful.  A 
mechanical  root-canal  filling  is  rarely  satis- 
factory; such  drugs  as  creosote,  oil  of  cloves, 
thymol,  aristol,  paraform,  alphozone,acetozone, 
tricresol,  and  formaldehyde,  are  advisable  ;  one 
or  more  of  the  liquids  mixed  with  one  of  the 
powders  or  oxide  of  zinc  to  form  a  paste,  and 
followed  in  the  canal  with  a  gutta-percha  cone, 
and  covered  with  oxy-chloride,  forms  a  satis- 
factory filling.  Balsam  of  Peru  is  sometimes 
used  in  these  cases.  The  size  of  the  apex,  and 
the  pathological  condition  of  the  canal  and  the 
tissues  beyond,  determine  the  power  of  the  drug 
to  use.  If  the  root-canal  is  very  fine,  and  there 
is  any  reason  to  believe  that  it  has  not  been 
cleaned  out  to  the  apex,  under  no  circumstances 
16 


should  the  root-canal  filling  he  forced  in  under 
rubber  pressure. 

Root-Canals  that  have  been  the  Seat  of  Infectious 
Matter  for  a  Short  Period,  or  from  which  the  pulp 
has  been  removed  iunuediately  after  its  death, 
so  that  in  either  case  there  is  no  reason  to  believe 
that  there  Ls  any  mechanical  or  chemical 
irritation  of  the  tissues  beyond  the  apex,  or 
any  penetration  of  these  tissues  with  infectious 
matter,  should  be  filled  with  chloro-percha, 
gutta-percha,  and  oxy-chloride  of  zinc,  as  before 
described. 

Fine  Crooked  Root-Canals,  in  which  the  Pulp 
is  not  all  dead  and  it  would  be  unwise  to  push 
arsenic  to  a  sufficient  depth  in  the  canal  to 
destroy  it,  and  in  which  if  the  pulp  were  all 
destroyed  it  could  not  all  be  removed,  may  be 
fiUed,  if  immediate  treatment  is  required, 
by  squeezmg  a  solution  of  phenol  into  them, 
followed  by  one  of  the  other  antLseptic  root- 
fillings. 

Root-Canals  that  have  Large  Apical  Openings,  or 
those  which  have  been  punctured  in  o})erating, 
or  root-canals  of  deciduous  teeth  that  have  been 
the  seat  of  mfection  and  are  otherwise  ready  for 
filling,  may  be  satisfactorily  filled  at  the  end 
with  Beck's  bismuth  paste.  The  paste  may  be 
warmed,  and  carried  into  the  canal  with  a 
heated  broach,  or  by  pressure  with  rubber. 
Formula — 


No.  2  Bismuth  Sub-nitrate    . 

.      30  parts 

Yellow  Vaseline 

.      60     „ 

Wliite  Wax       .... 

.       5     „ 

Paraffin 

.        5     „ 

Punctured,  Absorbed,  and  Fractured  Roots. 
Roots  that  are  punctured  m  operating,  and  in 
which  the  root-canal  is  aseptic,  should  be  fiUed 
at  once  with  some  substance  like  gutta- 
percha, as  otherwise  the  tissue  will  penetrate 
the  openmg  into  the  canal,  and  become  irritated 
by  the  rough  edges,  and  uifected,  and  give  but 
little  chance  of  successful  treatment  later. 
Roots  of  the  anterior  teeth  perforated  by  caries 
more  than  three  or  four  millimetres  below  the 
gum  margin  can  rarely  be  successfully  treated ; 
when  the  tissue  is  being  pressed  out  of  the  cavity, 
a  periodontal  inflammation  is  almost  certain  to 
occur.  Perforation  by  caries  through  the  floor 
of  the  pulp-chamber  of  molars  is  not  much  more 
amenable  to  treatment.  If  the  canals  are  not 
infected,  or  can  be  readily  treated  and  brought 
into  condition  to  fill,  the  case  is  simplified. 
The  protruding  tissue  may  be  anaesthetized, 
and  removed  with  a  large  spoon-excavator,  and 
the  surface  cauterized  with  phenol ;  at  the 
next  sitting  gutta-percha  may  be  placed  over 
the  openmg.  If  the  puncture  is  small,  and  little 
or  no  previous  infection  existed,  such  roots  often 
remain  comfortable  for  years,  but  are  of  doubt- 
ful utility  as  supports  for  crowns  or  bridges. 


482 


Roots  of  permanent  teeth  become  absorbed 
when  there  has  been  excessive  irritation,  either 
from  overwork  or  infection.  As  the  end  of  the 
root  is  absorbed  the  root-canal  opening  becomes 
larger.  Though  the  future  of  such  roots  is  not 
bright,  they  may  be  made  comfortable  and 
useful  for  years ;  the  canal  when  brought  into 
proper  condition  should  be  filled  at  the  apex 
with  bismuth  paste.  Occasionally,  irritating 
drugs  or  unwise  mstrumentation  has  caused  a 
liquid  exudate  to  come  from  an  abnormally 
large  apical  opening  every  time  the  dressmg  is 
removed.  Dentists  have  been  known  to  con- 
tinue to  irritate  the  tissue  at  the  end  of  such 
roots  with  instruments  and  poisonous  drugs 
for  months  and  even  years,  without  knowmg 
that  their  treatment  was  the  sole  cause  of  their 
trouble.  All  that  such  cases  need  is  to  be 
allowed  to  heal ;  the  canal  should  be  dried  out 
as  carefully  as  possible,  and  bismuth  paste, 
paraffin,  or  gutta-percha,  squeezed  tightly  into 
the  apex,  and  over  this  a  test  filling  placed  for 
some  time.  Li  no  case  is  it  wise  to  go  on 
treating  a  root-canal  for  weeks  and  months ;  a 
correct  diagnosis  will  obviate  many  useless 
courses  of  treatment  and  much  loss  of  time. 

Fractured  or  Split  Roots  can  never  be  success- 
fully bound  together,  and  the  root  fiUed. 
Infection  will  certauily  occur  in  the  line  of  a 
fracture  and  may  be  a  source  of  irritation  as 
long  as  both  of  the  fragments  remaui.  If  one 
fragment  is  not  well  enough  supported  to  retaiir 
a  crowni  or  filling  they  should  both  be  removed. 

Root-Canals  in  which  Broaches  have  been  broken. 


and  from  which  they  camiot  be  at  once  removed, 
are  among  the  most  difficult  cases  due  to  accident 
that  are  dealt  with  in  dentistry.  If  there  is 
room  in  the  cavity  to  grasp  the  end  of  the  broach, 
it  may  be  easily  removed,  but  this  must  be 
attempted  with  care.  If  it  is  out  of  reach  of 
everything  except  another  broach,  and  the  canal 
is  fine,  and  the  root  difficult  of  access,  and  the 
canal  not  infected,  it  may  be  as  well  to  fill  the 
canal  with  a  dismfectant  root-canal  fillhig  at 
once.  The  chances  for  its  removal  are  remote 
indeed ;  it  is  better  to  leave  the  broken  broach 
than  to  puncture  the  root  in  attempts  to  driU 
it  out.  If  the  canal  is  infected,  and  the  accident 
occurred  in  attempts  to  relieve  pain  from  an 
abscess,  there  is  little  hope  for  the  root ;  even 
if  the  abscess  is  opened  from  without,  it  wiU 
probably  recur,  because  of  the  remainmg 
infection  in  the  canal.  Magnets  and  solvents 
of  steel  have  been  recommended,  but  the  cases 
in  which  they  succeed  are  very  rare.  Iodine 
has  been  recommended  by  all  the  dental  text- 
books smce  some  one  thought  of  it  who  knew  of 
its  corroding  power  on  steel ;  the  difficulty  is 
that  the  agent  camiot  be  placed  in  contact  with 
the  steel  where  it  is  tight  in  the  canal. 

A.  E.  W. 

BIBLIOGRAPHY 

(1)  Black,  G.  V.     Operative  Dentistry,  Vol.  I,  p.  111. 

(2)  Black,    G.    V.     Address   on    Operative   Dentistry 

and  Bacteriology. 

(3)  Webster,  A.    E.     Dominion   Dent.   Jour.,  April, 

1900. 


CHAPTER   XXVIII 

THE   TREATMENT   OF   CHILDREN    AND   CHILDREN'S   TEETH 


'Little  can  be  accomplished  for  grown-up  people;  the  intelligent  man  begins  with  the  child." — Goethe. 


A  CORRECT  appreciation  of  the  importance 
of  healthy  infancy  and  cliildhood  cannot  be 
over-estimated.  By  guiding  development  along 
normal  chamiels,  and  as  far  as  possible  guarding 
the  child  from  acquiring  many  of  the  ills  that 
are  knoM'n  to  affect  development,  untold  misery 
in  after-life  may  be  avoided,  and  the  faithful 
work  of  the  skilful  dental  surgeon  acquire  a 
profound  significance  little  dreamt  of  by  his 
predecessors. 

Writers  on  this  subject,  with  few  exceptions, 
have  only  considered  the  treatment  of  the  child 
temperament,  the  deciduous  teeth,  and  the 
relationship  between  the  practitioner  and  his 
young  patient  when  in  the  dental  chair.  Wliile 
endorsing  all  that  has  been  -wTitten  concerning 
the  kindness,  gentle  firmness,  and  thoroughness, 
that  must  be  displayed  by  every  right-minded 
operator  when  relieving  painful  conditions,  it 
seems  of  still  greater  importance  to  discuss  how 
these  conditions  may  be  j)revented. 

The  subject  appears  to  resolve  itself  very 
naturallj',  therefore,  into  the  consideration  of — 

(1)  The    prevention    of    dental    disease    in 

children. 

(2)  The  treatment  of  such  disease,  when  it  has 

unfortunately  occurred. 

PREVENTION 

In  the  broadest  sense,  the  Prevention  of  Dental 
Diseasevawsi  start  fromthe  very  earliest  moments 
of  existence.  The  environment  of  a  child 
before  he  or  she  is  brought  for  operative  treat- 
ment must  certainly  be  considered,  and  while 
some  %viiters  maintain  that  the  majority  of 
children  are  horn  normal  and  healthy,  it  seems 
only  natural  that  the  condition  of  the  mother 
while  carrying  a  chUd  should  not  be  neglected. 
Further  it  is  most  essential  that  the  dental 
practitioner  should  make  a  close  study  of  the 
correct  methods  of  feeding  the  young,  and  the 
relative  value  of  food-stuffs,  so  that,  although 
not  disregarding  the  duties  of  the  family 
physician,  he  can  also  impart  this  knowledge 
to  parents,  guardians,  and  nurses,  and  in  simple 
language  lay  do-\ra  on  broad  lines  rules  of  diet 
that  if  judiciously  carried  out  will  prove  a 
"  treatment  "  of  inestimable  value. 


483 


Sim  Wallace  has  recently  summed  up  the 
present  knowledge  on  this  subject,  and  has 
clearly  laid  down  a  rational  scheme  for  the 
prevention  of  dental  disease  in  children.  In 
his  argument  he  goes  back  to  the  environment 
of  children  under  natural  conditions,  and  tries  to 
reproduce  this  natural  state  under  tlie  complica- 
tions of  modern  civilization.  Children's  mouths 
under  natural  conditions  were  in  a  much  more 
hygienic  state  than  at  present,  caries  un- 
doubtedly being  much  less  common  formerly 
than  it  is  now.  How  did  such  hygienic  con- 
ditions obtain  without  elaborate  artificial  aids  ? 
One  is  forced  to  the  only  possible  conclusion, 
that  it  must  be  a  difference  in  diet;  and  the 
regulation  of  diet  properly  understood  is  the 
foundation  of  the  prevention  of  dental  disease. 

All  authorities  are  agreed  that  where  at  all 
practicable,  feeding  from  the  breast,  preferably 
the  mother's,  is  most  desirable ;  and  although 
touching  on  the  province  of  another  i^art  of  this 
work,  it  may  be  i^ointed  out  that  the  con- 
dition of  the  teeth  is  so  bound  up  with  their 
individual  positions,  and  the  development  and 
relationship  of  the  jaws,  that  too  great  stress 
cannot  be  laid  on  the  advice  to  resort  to 
natural  means  of  feeding,  to  abandon  such  an 
artificial  environment  as  bottles,  artificial  teats, 
etc.,  and  such  acquired  habits  as  thumb-suck- 
ing and  the  like.  (See  Chaps.  IV,  V.)  It  is 
to  be  regretted  that  occasional  disability  pre- 
vents natural  feeding  from  being  universally 
feasible.  One  cannot  too  strongly  condemn  the 
attitude  of  those  who  have  the  physical  perfec- 
tion of  future  generations  so  little  at  heart, 
as  to  shirk  their  natural  and  self-elevating 
responsibilities. 

Some  authorities  believe  that  most  infantile 
disorders  coincident  with  teething,  usually 
attributed  to  a  disturbance  of  the  nervous 
system,  or  to  pyrexia  induced  by  pain,  are 
really  due  to  infection  through  the  mouth, 
which  is  then  in  a  state  of  lowered  vitality, 
and  so  more  liable  to  the  attacks  of  pathogenic 
micro-organisms.  Therefore,  at  this  period  of 
life  very  great  care  should  be  taken  not  to 
neglect  the  hygiene  of  the  mouth.  An  infant, 
if  properly  treated,  has  already  become  accus- 
tomed  to   having  the  mouth  wiped  out  with 


■±8-1 


boro-glyceride,  or  a  similar  prej)aration,  applied 
on  lint  wrapped  round  the  index  finger  (cotton- 
wool having  been  abandoned  on  account  of  the 
loose  fibres) ;  and  this  same  treatment  must 
now  be  continued  still  more  thoroughly. 

The  dangers  of  mouth-breathing  from  the  very 
earliest  ages  should  be  pointed  out.  Sim 
Wallace  claims  that  breathing  cold  damp  air  at 
night  is  the  prime  cause  in  the  production  of 
adenoids  and  nasal  obstruction,  and  that  there- 
fore infants  should  sleep  in  rooms  -with  closed 
windows.  This  is  probably  an  overstated 
reaction  against  the  stupidity  that  cannot 
distinguish  between  a  bedroom  kept  like  an 
ice-house  and  one  in  which  there  is  a  cnculation 
of  fresh  air,  or  between  the  enormous  differences 
there  are  in  the  humidity  of  the  atmosphere 
from  day  to  day.  Parents  should  be  -Harned 
at  any  rate  of  the  obvious  risk  of  cold  damj}  air, 
and  keep  children's  bedrooms  warm  and  dry. 
Some  laryngologists  advocate  that  the  doors  of 
children's  bedrooms  should  be  kept  open  in  all 
cold  damp  weather,  rather  than  the  windows. 
Bedroom  fires  cannot  be  reasonably  insisted 
on  in  every  household. 

The  danger  of  nasal  obstruction  in  children 
is  so  grave,  that  one  wTiter  even  goes  so  far 
as  to  place  mouth-breathing  as  of  the  first  im- 
portance in  the  production  of  a  functionless 
mouth,  and  therefore  as  a  direct  cause  of  the 
disasters  following  loss  of  function. 

WhUe  agreeing  that  mouth-breathing  may  be 
considered  one  of  the  important  indirect  causes 
of  malformation  of  the  jaws  and  caries  of  the 
teeth,  it  does  not  seem  at  all  clear  why  in  itself 
mouth-breathing  should  be  supposed  to  produce 
"  functionless  "  mouths,  as  at  the  worst  it  can 
but  impair  function.  Many  cases  are  seen  of 
unilateral  malocclusion,  qiute  unaccompanied 
by  nasal  obstruction,  which  renders  the  mouth 
far  less  "  functional  ",  as  far  as  mastication 
goes,  than  some  cases  of  double  post-normal 
occlusion  accompanied  by  mouth-breathing ;  and 
even  if  a  child  chews  between  gasps  for  breath, 
or,  as  one  may  say,  "  bites  with  its  mouth  open," 
the  mouth  can  hardly  be  described  as  "  function- 
less ".  It  is  certainly  open  to  doubt  whether 
mouth-breathing  children  "  bolt  their  food " 
more  than  others  improperly  brought  up. 

But  impaired  function  of  the  saiivary  glands 
is  undoubtedly  found  in  cases  of  mouth- 
breathing,  and  the  teeth  are  not  properly 
bathed  in  alkaline  saliva. 

It  will  be  seen  from  the  foregoing  that 
the  dental  surgeon  should  begin  to  exert  his 
influence  before  he  even  sees  his  patient,  and 
that  the  early  years  of  life  have  far  too  great  an 
importance  on  the  child's  future  to  be  neglected 
by  him. 

Following  the  admirable  plan  of  relying  on 
natural  methods,  dii'ectly  the  teeth  of  a  child 


begin  to  erupt  they  must  be  allowed  to  perform 
their  natural  functions  ;  tlie  incisors  must  gnaw, 
and  then  the  molars  grind,  and  in  this  wny  the 
jaws  and  muscles  of  the  jaws  are  stimulated  to 
the  proper  amount  of  development ;  and  if  the 
teeth  erupt  in  properly  developed  jaws,  the 
danger  of  caries  becoming  more  active  through 
malposition  of  teeth  or  jaws  is  entirely  elimi- 
nated. A  child  must  be  trained  from  the  very 
first  to  masticate  hard  things  and  to  chew 
thoroughly ;  complete  insalivation  of  the  food 
follows,  fibrous  material  is  left  in  the  mouth  to 
the  last,  and  no  stagnation  of  carbo-hydrates 
takes  place ;  the  teeth  have  Nature's  own 
cleansers  and  polishers ;  and  from  their  eruption 
till  their  loss  become  and  remain  functional. 

TREATMENT 

Having  considered  the  most  important  points 
in  the  prevention  of  dental  disease  in  children, 
one  naturally  passes  to  the  operative  treatment 
that  may  become  necessary  owing  to  the  neg- 
lect or  ignorance  of  the  above  simple  primary 
precautions.  Great  emphasis  shoijld  be  laid 
on  a  carefully  thought-out  plan  of  treatment  at 
a  child's  first  visit ;  and  parents  do  incalculable 
harm  to  many  children  by  representing  the 
dentist  as  a  necessary  bogey,  to  visit  whom 
persuasive  bribes  must  be  offered.  It  seems 
almost  unnecessary  in  these  days  to  enforce 
the  undesirabiLity  of  deception,  and  the  need 
of  making  these  visits  anticipated  with  pleasure 
rather  than  dread.  Regular  visits  should  be 
paid  from  the  earliest  ages,  models  taken, 
backward  development  noted,  and  practical 
lessons  given  in  oral  hygiene,  such  as  the 
vigorous  rinsing  of  the  mouth,  a  point  utterly 
neglected  by  the  majority ;  and  insistence  should 
be  renewed  on  the  order  of  food-stuffs  at  meals, 
never  eatmg  between  meals,  or  sleeping  with  a 
dirty  mouth. 

Deciduous  teeth  are  not  as  sensitive  as 
permanent  ones,  and  the  operator  has  to  combat 
fatigue  and  restlessness  in  his  little  patients 
rather  than  acute  suffering.  The  dental  engine 
should  be  used  with  great  caution,  and  never  for 
long  at  a  time.  By  interesting  a  chUd  in  the 
mechanism  of  the  hand-piece,  or  explaining  the 
revolving  burr  rather  as  a  plaything  than  a 
cutting  instrument,  and  by  adopting  many 
similar  devices,  much  anticipatory  dread  may  be 
overcome. 

In  most  cases  a  single  use  of  the  engine  viiW 
suffice  for  each  cavity,  but  let  the  burrs  be  small 
and  shai-p,  for  children  are  often  frightened  by 
the  "  chatter  "  of  too  big  an  instrument.  Crown 
cavities  can  be  opened  up  very  rapidly  by  small 
cross-cut  fissure-burrs,  and  one  cut  will  suffice 
to  divide  the  whitened  weak  enamel  over 
approximal  molar  cavities ;    it  is  at  this  early 


485 


stage  of  caries  that  such  teeth  should  be  filled, 
and  the  importance  of  so  doing  forms  one  of  the 
strongest  reasons  for  regular  examination  by 
the  expert.  If,  however,  after  the  display  of  a 
reasonable  amount  of  patience,  a  child  prove 
himself  unamenable,  and  nervous  dread  of 
"  machinery  "  cannot  be  overcome,  the  best 
practice,  where  cavities  are  too  small  to  be 
prepared  by  hand,  is  to  dehydrate  with  absolute 
alcohol  and  flush  full  ysitii  oxy -phosphate  of  zinc 
or  copper,  thereby  saving  the  teeth  until  the 
child  reaches  a  more  reasonable  age ;  it  is  wise 
not  to  force  children  beyond  certain  limits. 

The  above  method  will  be  found  especially 
desirable  -with  deep  fissures  in  first  molais  that 
seem  doomed  to  become  carious ;  the  thin  line 
of  phosphate  seems  to  wear  extraordinarily 
well,  and  supplemented  by  a  judicious  diet 
renders  the  teeth  immune  from  further  trouble. 
Operators  must  chiefly  concern  themselves  with 
the  occlusal  and  approximal  surfaces  of  the 
molars,  many  of  these  teeth  being  retained  five 
or  more  years  after  the  loss  of  the  deciduous 
incisors. 

The  same  principles  of  cavity  preparation 
can  be  applied  to  deciduous  teeth  as  to  perma- 
nent ones,  but  the  great  principle  of  extension 
for  prevention  need  not  be  so  rigorously  follo^\'ed, 
and  advantage  should  be  taken  of  overhanging 
cusps  of  enamel  for  retention  purposes,  the 
masticating  strain  on  the  grindmg  surfaces  not 
being  great  enough  to  break  these  points  down 
if  the  operation  is  carried  out  with  proper 
judgement.  It  is  also  wiser  to  leave  a  dis- 
infected layer  of  softened  dentine  over  the  pulp 
of  a  deciduous  tooth  than  produce  a  traumatic 
exposure.  If  this  unfortunately  occurs,  the 
child  is  not  likely  to  suffer  severely  at  the  time, 
but  with  a  dead  deciduous  tooth  there  is  always 
risk  of  infection,  and  subsequent  abscess,  even 
when  the  treatment  has  been  most  thorough. 

The  child's  small  physical  endurance  must  not 
be  forgotten,  and  the  benefit  of  painless  thorough 
\\ork  for  the  patient  must  be  a  greater  con- 
sideration than  the  inconvenience  to  guardians 
of  constant  visits,  who  usually  like  to  have  a 
great  deal  done  at  once  and  "  get  it  over  ",  when 
their  own  nervous  organization  is  not  under 
consideration.  Therefore,  do  not  let  children 
be  in  the  chair  too  long,  and  let  the  intervals 
between  visits  be  long  enough,  if  practicable, 
to  obliterate  the  remembrance  of  any  dis- 
agreeables that  may  have  been  experienced. 

The  rapidity  with  which  an  operation  can 
be  performed  naturally  brings  one  to  the  filling- 
materials  to  be  employed,  and  to  the  choice 
of  those  that  can  be  used  efficiently  and  quickly. 

For  the  front  teeth  nothing  can  be  better 
than  one  of  the  hydraulic  varieties  of  oxy- 
phosphate  of  zinc,  as  it  can  be  allowed  to  get 
wet  so  soon  after  insertion;  the  colour  is  not 


objectionable,  and  the  teeth  require  little  more 
preparation  than  the  removal  of  carious  material. 
Such  fillings  efficiently  preserve  the  teeth  until 
their  natural  loss.  A  silver-tin  alloy  should  be 
used  for  the  back  teeth  where  at  all  practicable, 
and  should  be  inserted  with  full  approximal 
contour;  this  perfects  the  masticating  surface, 
frees  the  teeth  from  all  tenderness  due  to  im- 
paction of  food,  and  from  the  consequent  dan- 
ger of  too  early  loosening.  It  cannot  be  too 
frequently  pointed  out  that  tenderness  of  deci- 
duous teeth  involves  loss  of  function,  and  lays 
the  foundation  of  the  habit  of  food-bolting  and 
of  all  the  consequent  evils  of  this  bad  habit ;  and 
that  to  restore  function  is  the  operator's  ideal. 

Copper  amalgam  can  never  retain  a  perfectly 
restored  contour  for  long,  as  the  wasting  process 
occurs  before  the  loss  of  the  teeth,  and  non- 
eleansable  pockets  are  formed,  with  the  dis- 
appearance of  the  contact  point.  But  when  a 
large  number  of  children  have  to  be  dealt  with 
speedily,  and  the  operator's  time  enters  into 
the  question,  this  form  of  alloy  is  probably  the 
most  advisable,  as  it  is  slow-setting,  easily 
manipulated,  inexpensive,  and  does  not  con- 
tract. At  any  rate  it  provides  a  ready  means 
of  combatmg  otherwise  insuperable  difficulties, 
but  caimot  be  recommended  for  private  practice. 

The  use  of  rubber-dam  at  an  early  age  is  to 
be  deprecated,  and  the  mouth  must  be  kept  dry 
in  other  ways ;  in  very  «et  mouths  much  may 
be  done  temporarily  with  base-plate  gutta- 
percha dipped  in  oil  of  cajuput.  Wliere  gutta- 
percha is  used  to  fill  two  adjacent  approximal 
cavities  it  vnll  be  found  most  useful  to  bridge 
over  the  intervening  space  with  a  flooring  of 
platinum,  thereby  avoiding  all  pressure  on  the 
gum.  The  use  of  gutta-percha  also  has  the 
effect  of  stimulating  the  growth  of  space,  which 
in  under-developed  mouths  is  very  desirable ; 
and  this  material,  being  pliable,  allows  each 
tooth  its  o^\n  natural  motion  without  itself 
becoming  loosened.  If  two  adjacent  alloys  or 
cements  are  inserted  in  one  operation  they 
should  always  be  divided  by  a  very  fine  blade 
immediately  aftervvards,  or  a  fine  blade  matrix 
should  be  fixed  before  the  fillings  are  commenced. 

Oxy-phosphate  of  copper,  in  the  hands  of 
many  operators,  has  not  proved  the  success 
that  was  anticipated.  It  is  difficult  to  mani- 
pulate and  uncertain  in  its  behaviour ;  while 
good  results  have  been  obtained  with  it,  its 
very  colour  makes  examination,  where  it  has 
been  used,  tedious,  and  its  lasting  properties 
are  doubtful. 

Wlien  caries  has  extended  as  far  as  the  pulp- 
chamber,  very  careful  judgement  in  procedure 
is  needed.  The  extirpation  of  a  live  pulp  under 
cocaine  anaesthesia  is  often  quite  simple,  the 
drug  being  readily  absorbed  by  the  very  vascular 
pulp ;   temporary  relief  may  be  given  with  pure 


486 


carbolic  acid  or  oil  of  cloves,  and  very  often 
the  pulp  can  be  readily  removed  at  a  subsequent 
visit.  Devitalizing  fibre  or  arsenious  acid  may 
be  used  with  great  caution,  but  only  in  minute 
quantities,  and  should  be  avoided  as  a  routine 
practice,  as  other  less  dangerous  drugs  ^dll  in 
most  cases  suffice.  Teeth  in  some  mouths 
seem  to  tolerate  perfectly  the  removal  of  the 
pulp  and  the  filling  of  the  pulp-cavity  with  an 
antiseptic  paste  covered  ^^•ith  oxy-phosphate  or 
alloy ;  other  teeth  seem  doomed  from  the  time 
the  pulp  becomes  affected. 

When  a  deciduous  tooth  has  become  septic, 
the  usvial  f)rocedure  for  cleansing,  etc.,  may  be 
folloM'ed,  and  since  the  introduction  of  tricresol- 
formalin  paste,  this  treatment  has  become  more 
certain.  No  attempt,  however,  should  be 
made  to  fill  the  root-canals,  and  the  premature 
loss  of  such  teeth  may  usually  be  anticipated, 
varying  of  course  with  the  age  at  which  the 
infection  took  place.  But  the  saving  of  such 
teeth  for  a  time  at  any  rate  may  be  of  lasting 
benefit  to  the  whole  denture.  It  is  most 
important,  however,  that  septic  or  periostitic 
teeth  should  be  non-existent;  and  to  render 
a  mouth  free  from  tenderness  or  sepsis,  extrac- 
tion should  be  resorted  to  if  all  else  fails.  Wien 
deciduous  teeth  have  had  to  be  removed  from 
the  arch  much  earlier  than  normal,  the  possi- 
bility of  restoration  of  function  by  a  vulcanite 
splint  should  be  considered,  the  age  at  which  the 
extraction  had  to  be  performed  being  given  due 
weight ;  if  this  was  early  enough  to  cause  a 
backward  movement  of  the  incisors,  then  the 
treatment  should  be  adopted,  even  if  the  first 
deciduous  molars  only  are  lost ;  if  later,  it  may 
be  advisable  only  to  insert  a  skeleton  plate,  -with 
a  view  to  holding  the  developing  space  between 
the  distal  surface  of  the  deciduous  canine  (or 
the  first  deciduous  molar  or  its  successor)  and 
the  medial  surface  of  the  first  permanent  molar. 
There  must  obviously  be  a  period  of  transition 
between  the  two  dentitions  when  the  mouth 
camiot  be  fully  functional.  With  regard  to  the 
insertion  of  any  such  apparatus,  again,  the 
temperament  of  the  little  patient  has  to  be 
given  careful  consideration. 

J.  F.  Colyer  and  others  recommend  not  only 
the  extraction  of  septic  deciduous  molars,  but 
also  their  antagonists,  even  ^^'hen  sound ;  and 
in  the  case  of  second  deciduous  molars  such 
treatment  has  the  isolation  of  the  very  important 
first  molars  as  its  raison  d'etre.  Incidentally 
it  is  claimed  that  even  if  the  opposing  tooth  is 
sound  it  is  functionless,  and  therefore  better 
away.  Wliile  not  -vvishmg  to  enter  into  an 
argument  as  to  whether  mastication  is  the  sole 
function  of  a  molar  tooth,  one  may  point  out 
that  it  seems  to  have  been  forgotten  that  in  a 
normal  jaw  any  one  tooth  has  two  antagonists, 
and  that  the  extraction  of  one  opponent  only 


cripples,  but  does  not  suppress,  its  function  of 
mastication  altogether.  One  should  also  dis- 
tinguish between  the  desnability  of  extractiag 
the  second  lower  deciduous  molar  when  the 
upper  has  gone,  to  preserve  the  correct  occlusion 
of  the  first  permanent  molars  (othenvise  a 
condition  of  induced  pre-normal  occlusion  of 
the  first  upper  permanent  molar  may  arise), 
and  the  desirability  of  keeping  the  second  upper 
deciduous  molar  when  sound,  to  increase  the 
function  of  the  first  lower  permanent  molar. 
(See  Chapter  V,  p.  92.) 

The  teaching  of  removal  of  incurably  septic 
deciduous  teeth  has  been  confused  by  some 
Avith  the  wholesale  removal  of  deciduous  teeth 
with  pulps  unaffected,  and  not  beyond  treat- 
ment. Such  a  method  may  lead  to  very 
disastrous  results,  especially  when  post-normal 
occlusion  is  present;  and  even  when  the  teeth 
are  septic,  extraction  only  should  be  adopted 
when  it  is  felt  that  no  other  treatment  would 
produce  asepsis,  and  so  eliminate  any  danger 
to  the  general  health. 

The  use  of  nitrate  of  silver  in  teeth  becoming 
very  rapidly  carious  has  been  recommended  as 
arresting  decalcification.  Great  care  should 
be  used  in  its  application,  the  soundest  method 
being  to  melt  a  small  bead  on  to  the  end  of  a 
broken  instrument.  This  ought  to  be  looked 
on  as  a  temporary  measure  only,  as  it  will  be 
found  that  a  reconsideration  of  and  strict 
attention  to  diet  is  of  far  greater  importance. 

The  value  of  the  use  of  X-rays  in  children's 
mouths  should  never  be  forgotten,  as  by  this 
means  much  difficult  diagnosis  is  made  quite 
simple. 

Lastly,  a  child's  seat  attachment,  made  by 
splitting  and  hinging  half  the  back  of  the  present 
dental  chair,  will  be  found  of  great  convenience ; 
this  makes  both  the  patient  and  the  operator 
much  more  at  ease. 

To  sum  up,  "  Prevention  is  better  than  Cure  ", 
and  attention  to  normal  diet  and  hygiene  is  the 
secret  of  prevention. 

Treatment  should  be  simple,  speedy,  and 
permanent  M'here  at  all  possible.  A  child's 
power  of  resistance  to  fatigue  is  not  great,  and 
an  endeavour  should  always  be  made  to  elimi- 
nate that  well-known  dread  of  our  too  often 
abused  profession  that  makes  the  dental  chair 
a  positive  nightmare,  instead  of  a  place  of 
comfort  and  relief. 

G.N. 

BIBLIOGRAPHY 

(1)  Black,  G.  V.     Operative  Dentistry. 

(2)  Colyer,  J.  F.     Dental  Surgery  and  Pathology. 

(3)  Discussion  on  the  Causes,  Effects,  and  Treatment, 

of  Dental  Disease    in  Childhood.     Brit.    Med. 
Jour.,  Nov.  23,  1907,  p.  1485. 

(4)  Discussion  on  Teething  and  its  Alleged  Troubles. 

Brit.  Med.  Jour.,  Aug.  22,  1908,  p.  468. 

(5)  Johnson,  C.  N.     Operative  Dentistry. 


CHAPTEE   XXIX 

DISEASES  OF  THE  PERIODONTAL  MEMBRANE 


Anatomy. — Between  the  root  of  each  tooth 
and  its  bony  socket  is  a  layer  of  tissue  termed 
the  Periodontal  Membrane.  This  membrane  is 
the  analogue  of  the  ligamentous  structures  ui 
joints,  being  composed  of  white  fibrous  con- 
nective tissue  richly  supplied  %\ith  vessels,  and 
nerves,  and  cells  of  various  types.  From  the 
alveolar  wall  the  fibres  of  the  membrane  pass 
obliquely  towards  the  apex  of  the  root,  allow- 
ing the  tooth  a  limited  amount  of  movement. 
Hence  these  fibres  may  be  regarded 
as  forming  a  suspensory  ligament 
(see  Fig.  539). 

Besides  supportmg  the  tooth 
in  its  position,  the  membrane 
furnishes  nourishment  to  the 
cementum  of  the  root  and  the 
bone  of  the  alveolus  between 
which  it  is  placed.  The  blood 
supply  is  abundant.  Some  vessels 
are  derived  from  the  arteries  of 
the  bone  and  some  from  the  arteries 
entering  the  apex  of  the  tooth, 
whilst  others  come  from  the  gum 
over  the  margin  of  the  socket.  It 
should  also  be  observed  that  in  the 
apical  area  the  space  between  the 
tooth  tissue  and  the  bone  is  con- 
siderably greater  than  at  other 
places. 

At  the  free  margm  the  fibres  are 
dense  and  form  a  firm  attachment 
between  the  neck  of  the  tooth  and 
the  bone ;   this  group  of  fibres  is 
called     the     "  dental     ligament ". 
Superficial   to    this,   and   between 
the   tooth  and    the   gum,   is    the 
"  gingival  space  ".     In  this  space  the  epitheUum 
covering  the  inner  surface  of  the  gum  margin 
in  contact  with  the  neck  of  the  tooth  is  comjDosed 
of  soft,  round,  polygonal  cells.     Though  not  of  a 
glandular    structure,    this    epithelium    secretes 
many  small  rounded  cells,  lymphoid  in  character, 
and  termed  mucous  corpuscles.     To  this  epi- 
thelium the  term  "  gingival  organ  "  has  been 
applied.     As    time    advances    the    membrane 
decreases  in  thickness  ;  by  the  formation  of  bone 
on  the  wall  of  the  alveolus,  and  of  cementum  on 
the  surface  of  the  root,  the  thick  mass  of  the 
membrane  is  reduced,  until  finally,  in  old  age 


most  of  the  vessels  are  to  be  found  close  to  the 
surface  of  the  bone. 

The  Periodontal  Membrane  is  frequently  the 
seat  of  diseased  conditions,  and  common 
amongst  these  are  several  distmct  forms  of 
mflammation.  Various  groupings  of  these  in- 
flammatory affections  have  been  suggested  by 
different  authorities. 

For  example,  Arkovy  makes  the  following 
sub-divisions — 


Fig.  539. — -Longitudinal  section  of  the  periodontal  membrane  in  situ. 
D,  Dentine ;  C,  Cementum ;  P,  Periodontal  Membrane ;   B,  Bone. 

Acute  Periodontitis 

(1)  Acute  marginal  periodontitis. 

(2)  Acute  apical  periodontitLs. 
(.3)  Acute  circumscribed  periodontitis. 
(4)  Acute  diffuse  periodontitis. 
(.5)  Acute  purulent  periodontitis. 

(6)  Apical  abscess. 

(7)  Toxic  periodontitis. 

Chronic  Periodontitis 

(1)  Chronic  apical  periodontitis. 

(2)  Chronic  diffuse  periodontitis. 


487 


488 


(3)  Chronic  purulent  periodontitis. 

(4)  Chronic  granulomatous  periodontitis. 

(5)  Apical  necrosis. 

(6)  Total  necrosis. 

G.  V.    Black   suggests    a   clinical    classifica- 
tion for  diseases  of  the  periodontal  membrane  : 

(1)  Those  beginning  at  the  apex  of  the  root; 

(2)  those  begmning  at  the  gum  margin ;   and 

(3)  those  beginning  at  some  intermediate  por- 
tion of  the  periodontal  membrane.  Others  have 
classified  them  as  septic  and  non -septic,  or  as 
purulent  and  non-purulent.  But  the  grouping 
commonly  accepted  in  this  country  has  been 
adopted  here:  (1)  Acute  local  periodontitis; 
(2)  Chronic  local  periodontitis ;  (3)  General 
periodontitis ;  (4)  Chronic  suppurative  perio- 
dontitis. 

The  term  "  periodontitis  "  itself  signifies 
inflammation  of  the  jjeriodontal  membrane  and 
the  tissues  immediately  surrounding  the  tooth. 
The  great  majority  of  inflammatory  affections 
of  the  jaws  commence  in  the  periodontal 
membrane,  and,  next  to  hyperaemia  and  in- 
flammation of  the  pulp,  a  diseased  condition 
of  the  periodontal  membrane  is  the  commonest 
cause  of  toothache.  Local  periodontitis  is 
limited  to  inflammation  around  the  root-mem- 
brane of  one  or  two  teeth  ;  the  condition  may  be 
acute  or  chronic.  It  may  originate  near  the 
apex,  at  the  gingival  margin,  or  between  the 
gingival  margin  and  the  apical  space. 

1.  ACUTE    LOCAL    PERIODONTITIS 

Aetiology. ^ — The  aetiology  of  acute  local  perio- 
dontitis may  be  considered  under  three  head- 
ings— (1)  Traumatic,  (2)  Septic,  (3)  Chemical. 

Amongst  the  first  group,  the  following  causes 
should  be  included  :  a  blow  on  the  tooth,  a  fall, 
rapid  regulation,  irritation  arising  from  a  badly 
fitting  denture  or  crown,  faidty  occlusion  of 
teeth,  too  rapid  separation  of  teeth  preparatory 
to  filling,  careless  use  of  rubber-dam  clamps, 
perforation  of  the  wall  of  the  root,  or  the  passage 
of  an  instrument  through  the  apex  into  the 
membrane  during  the  treatment  of  the  root- 
canal.  An  instance  of  a  ease  of  acute  periodon- 
titis set  up  by  the  perforation  of  the  wall  of  a 
tooth  by  a  root  filling  is  seen  in  fig.  540. 

In  the  great  majority  of  cases,  however,  the 
trouble  arises  from  sepsis  due  to  death  and 
decompasition  of  the  pulp,  the  septic  matter 
passing  through  the  apical  foramen  of  the 
tooth.  Sepsis  may  also  spread  from  a  con- 
tiguous abscess,  a  "  pyorrhoea  "  pocket,  or 
dirty  instruments. 

Chemical  irritation  is  brought  about  by  the 
escharotic  action  of  strong  drugs  commonly 
used  in  the  treatment  of  teeth,  such  as  arseni- 
ous   acid,   formalin,   chloride   of   zmc,  etc.     A 


root-filling  projecting  beyond  the  apex  may 
produce  a  similar  result.  In  other  cases  a  mere 
extension  of  inflammation  from  a  non-septic 
pulp  may  occur.  It  should  also  be  noted 
that  the  continuity  of  structure,  and  the  fact 
that  vessels  to  the  pulp  and  the  periodontal 
membrane  arise  from  the  same  source,  do  at 
times  lead  to  an  extension  of  inflammation 
from  one  tissue  to  another. 

Pathology  and  Morbid  Anatomy. — The  patho- 
logical changes  that  take  place  in  periodontitis 
are  simflar  to  those  that  occur  in  inflammation 
of  other  soft  tissues.  After  the  injury,  a  tem- 
porary contraction  precedes  the  dilatation  of 
the  blood-vessels  and  the  acceleration  of  the 
blood  flow.  This  is  followed  by  retardation, 
and  the  blood  current  becomes  progressively 
slower  untU  stasis  is  reached.  Exudation  of 
lymph,    leucocytes    and    red    blood-corpuscles 


Fig.  540. — Acute  periodontitis  caused  by  perforation 
of  the  root  wall.  (From  a  specimen  in  Guy's 
Hospital  Museum.) 

through  the  vessel  walls  also  occurs.  If  the 
inflammation  is  slight,  and  not  of  bacterial 
origm,  the  process  may  end  at  this  stage  in 
resolution,  tjie  membrane  assuming  its  normal 
condition  after  the  lymphatics  have  taken 
up  the  exudation  and  the  debris  has  been 
removed  by  the  leucocytes.  The  inflammatory 
process  may  end  in  resolution,  suppuration,  or 
organization. 

In  cases  where  acute  local  periodontitis  is  due 
to  trauma  or  chemical  agents,  and  is  of  short 
duration,  the  mischief  commonly  terminates  in 
resolution,  but  if  it  follows  septic  infection 
through  bacterial  products  suppuration  is  the 
usual  result.  WTien  the  injury  is  slight,  and  of 
low  degree  but  prolonged,  it  leads  to  organiza- 
tion. Perforation  of  the  waU  of  the  root  may 
be  very  troublesome  and  resist  all  efforts  at 
treatment. 

Should  the   inflammatory  process   continue, 


489 


the  leucocytes  and  embryonic  cells  lose  their 
vitality  and  are  converted  into  pus  corpuscles. 
Tlie  pyogenic  organisms  cause  disintegration 
of  the  intercellular  substance  of  the  tissues  and 
this  becomes  liquefied,  pus  is  formed,  and  an 
alveolar  abscess  results.  In  the  process  of 
inflammation  the  membrane  becomes  thickened, 
rough,  and  blood-stained,  and  presents  areas  of 
cloudiness,  «hich  in  time  may  extend  over  the 
entire  surface.  If  the  tooth  is  now  extracted 
a  ragged  edge  presents  itself,  and  in  places  the 
membrane  may  be  stripped  from  the  cementum. 
Upon  microscopical  examination  the  fibrous 
tissue  of  the  membrane  is  found  to  be  infiltrated 
with  inflammatory  products.  Blood-vessels  are 
seen  to  be  dilatecl,  and  it  will  be  observed  that 
the  tissues  around  these  vessels  and  the  nerve- 
bundles  have  increased  in  bulk,  whilst  osteoblast 
cells  are  also  conspicuous. 

Signs  and  Symptoms. — Although  the  exciting 
causes  vary,  the  symptoms,  for  the  most  part, 
present  similar  characteristics.  The  first  sign 
of  inflammation  of  the  })eriodontal  membrane 
is  a  feeling  of  uneasiness  in  the  affected  tooth 
due  to  the  dilatation  of  the  blood-vessels.  There 
LS  an  inclination  to  press  the  tooth  against  its 


makes  the  pain  worse.  This  is  due  to  the  fact 
that  stasis  is  approaching  and  the  blood  cannot 
easily  be  expelled  from  the  vessels.  The  gum 
shows    signs    of    inflammation,    being    purple, 


Fig.  ,)1I.  AeiUr  inllauuu.unui  of  t\w  pLi-ioduutal 
membrane  in  situ.  Prepared  by  Hopewell- 
Smith's  process,  stained  with  haematoxylene. 
X   40. 

D,  Dentine;  C,  Cementum;  PM,  Periodontal  mem- 
brane, the  fibrous  tissues  of  which  are  crowded 
with  leucocytes  and  inflammatory  products. 

(Photo-micrograph  bij  permission  of  A.  Hopewell- 
Smith.)      {Dental  Manufacturing  Company,  Ltd.) 

antagonists,  thereby  bringing  momentary  relief 
because  the  pressure  drives  the  blood  out 
of  the  vessels  and  reduces  the  tension.  As 
the  inflammation  increases,  the  tooth  becomes 
too  tender  to  bite  upon  ;  pressure  now  only 
16  * 


Fig.  542.  —  Acute  inlianuuutiun  of  the  periodontal 
membrane.  The  same  as  Fig.  541.  X  250. 
F,  Comiective  tissue  fibres ;  I,  Inflammatory  cells 
and  products.  (Photo-micrograph  by  permission 
of  A.  Hopewell-Smith.)  (Dental  Manufacturing 
Company,  Ltd.) 

swoUen,  and  painful.  Later,  the  tooth  pro- 
trudes from  its  socket,  and  is  slightly  loose,  and 
a  deep,  dull,  constant  pain  ensues. 

The  intensity  of  the  symptoms  depends 
chiefly  upon  the  character  of  the  infection.  In 
the  traumatic  type  the  uiflammation  is  usually 
of  a  difii.ised  character  and  seems  to  involve 
the  whole  membrane,  but  the  symptoms  are 
less  severe  than  those  arismg  from  septic  condi- 
tions, and  if  there  is  no  infection  from  micro- 
organisms resolution  commonly  follows. 

If  suppuration  occurs  the  pain  at  first  is 
continuous,  and  is  accompanied  by  a  .sense  of 
fullness  and  throbbing.  The  tooth  also  becomes 
more  tender  to  percussion,  and  the  gum  around 
the  tooth  is  found  to  be  swollen  and  sensitive. 
The  severity  of  the  pam  at  this  stage  is  attributed 
to  pressure  on  the  sensory  nerve-endings. 
Eventually  the  swelling  becomes  defined,  and 
finally,  a  distinct  point  of  fluctuation,  indicathig 
the  formation  of  pus,  is  observed.  When  it  has 
made  its  way  through  the  bone  the  pus  wiU  tend 
to  Inirrow  into  the  soft  tissues,  and  this  will 
relieve  the  tension  once  more,  with  the  result 
that  the  pain  diminishes. 

The  signs  of  acute  local  periodontitis  may  be 
summarized  briefly  as,  (1)  tenderness  on  pres- 
sure, (2)  dull  percussion  note,  (3)  protrusion  and 


490 


loosening  of  the  tooth,  (4)  deepening  of  the  colour 
of  the  gum  locally.  The  general  symptoms  may 
include  feverishness,  rapid  wulse,  the  tongue  foul 
and  coated,  and  constipation.  Loss  of  appetite, 
nervousness  and  depression  usually  attend  the 
complaint. 

Treatment. — In  the  treatment  of  acute  local 
periodontitis  the  cause  of  the  irritation,  if  it 
still  exists,  should  be  removed  at  once  when 
•this  is  possible.  Such  treatment  may  include 
the  relief  of  faulty  occlusion  of  teeth,  the  removal 
of  a  badly  fitting  crown,  root-filUng,  or  denture. 
In  those  instances  where  the  mischief  has  been 
started  by  trauma  or  chemical  irritation,  the 
removal  of  the  cause  and  the  application  of 
counter-irritants  to  the  gum  may  be  all  that 
is  necessary  to  obtain  resolution. 

When  the  injury  has  been  severe,  or  the  dam- 
age by  chemical  agents,  such  as  arsenious  oxide 
or  formalin,  has  been  prolonged,  it  may  be  also 
necessary  to  scarify  the  gums  for  the  purpose 
of  promoting  bleeding,  and  to  employ  hot 
fomentations  and  constitutional  remedies,  in 
order  to  prevent  suppuration. 

If  the  injury  has  been  caused  by  the  passage 
of  an  instrument  through  the  apical  foramen, 
or  by  a  perforation  of  the  wall  of  the  root,  it 
is  very  important  to  keep  the  canal  of  the  root 
sterile  and  to  use  only  non-irritating  antisep- 
tics in  washing  it  out. 

Teeth  so  injured  rarely  recover  completely. 

In  treating  all  cases  of  periodontitis,  rest  is 
an  important  factor,  and  in  order  to  obtain  rest 
it  is  desirable  to  prevent  the  opposing  tooth, 
or  teeth,  from  occluding  with  the  affected  one. 
To  provide  for  this  a  metal  or  gutta-percha 
cap,  or  a  rubber-dam  guard,  as  suggested  by 
Flagg,  may  be  fixed  upon  a  tooth  on  the  opposite 
side  of  the  mouth,  or,  if  none  is  available  on 
that  side,  a  neighbouring  tooth  will  do.  Another 
method  of  raising  the  bite  from  the  tender  tooth 
is  to  employ  some  oxy-phosphate  of  zinc  and 
allow  it  to  set  on  the  occluding  surface  of  the 
crown  of  one  or  two  molar  teeth  that  are  not 
affected  by  the  inflammation. 

When  the  trouble  has  arisen  from  a  septic 
pulp,  or  if  bacterial  infection  has  subsequently 
occurred,  it  may  be  important  to  decide  at  the 
outset  whether  the  tooth  can  be  saved,  and  if 
unsavable  it  should  be  extracted  without 
delay.  It  is  perhaps  hardly  necessary,  at  the 
present  day,  to  lay  stress  on  the  importance  of 
getting  rid  of  the  tooth  as  soon  as  possible 
when  it  has  been  condeimied.  A  poj)ular 
notion,  which  at  one  time  found  support  even 
amongst  some  of  the  members  of  the  medical 
profession,  was  that  a  tooth  should  not  be 
extracted  during  the  stage  of  active  inflam- 
mation. This  has  long  been  recognized  as  a 
fallacy. 

When  it  is  thought  possible  to  retain  such  a 


tooth  the'root-canal  should  at  once  be  opened 
up  and  freely  drained.  Speedy  relief  from  pain 
depends  largely  upon  the  care  and  thoroughness 
with  which  this  oi^eration  is  carried  out.  In 
many  cases  the  affected  tooth  is  extremely 
tender  to  pressure,  and,  in  order  to  overcome 
this  trouble  during  the  process  of  drilling 
the  tooth,  it  may  be  supported  by  the  fingers 
of  the  left  hand,  or  better  still,  by  means 
of  a  temporary  splint,  which  can  be  easily 
moulded  out  of  a  piece  of  softened  modelling 
composition. 

In  opening  up  a  septic  root-canal  for  the 
treatment  of  these  cases  the  operator  must 
work  slowly,  and  when  the  pidp-cavity  has 
become  exposed  the  gases  should  be  allowed 
to  escape  gradually.  As  soon  as  a  broach  can 
be  admitted  into  the  canal  the  cavity  should 
be  syringed  or  washed  out  thoroughly  with 
some  strong  antiseptic  lotion  such  as  naph- 
thol  alcohol,  lysol,  tricresol,  or  formo-cresol, 
care  being  taken  to  protect  the  soft  tissues  of 
the  mouth  from  the  escharotic  action  of  the 
drugs. 
I  III  cases  where  the  pulp  has  become  de- 
I  vitalized  under  a  filling,  or  long  after  a  blow, 
the  cavity  should  be  left  open  for  twenty-four  or 
forty-eight  hours  so  that  the  gases  may  escape 
as  completely  as  possible  and  before  a  dressing 
is  sealed  in  the  cavity.  Great  care  must  always 
be  observed  to  avoid  forcing  septic  matter 
through  the  apical  foramen. 

Where  the  tooth  is  excessively  tender,  or 
if  the  patient  is  ill  and  must  be  seen  in 
bed,  the  operator  may  be  justified  in  making 
a  temporary  vent  by  the  shortest  route.  For 
this  purpose  an  opening  is  drilled  at  the  neck 
of  the  tooth  straight  into  the  pulp-cavity, 
when  promjjt  relief  usually  follows.  The  term 
"  rhizodontrophy  "  ^  has  been  applied  to  this 
form  of  treatment,  which  can  only  be  looked 
upon  as  a  temporary  expedient. 

If  suppuration  has  extended  to  the  alveolus 
and  to  the  soft  tissues  around,  free  incisions 
should  be  made  in  order  to  remove  the  pus  as 
quickly  as  possible,  and  hot  fomentations  should 
be  applied  inside  the  mouth  immediately  over 
the  inflamed  area.  The  old-fashioned  method 
of  applying  a  toasted  raisin  or  prune  to  the 
part  is  still  a  valuable  remedy. 

When  the  pus  is  finding  an  exit  at  the  neck 
of  the  tooth  extraction  will  be  indicated,  be- 
cause of  the  damage  already  done  to  the  perio- 
dontal membrane.  An  antiseptic  mouth-wash 
should  be  used  before  as  well  as  after  the 
extraction  of  the  tooth. 

Constitutional  treatment  will  frequently  help 
to  cut  short  the  inflammatory  process  and  to 
,  aUay  pain. 

1  Described  by  Hulnie,  British  Journal  of  Dental 
Science,  1865. 


491 


A  brisk  saline  purgative  such  as- 

B 

Magnesii  Sulphatis    . 
Magnesii  Carbonatis 
Aquam  Mentli.  Pip.  ad   . 

M.  ft.  mist. 


Oh 
gr.  XV. 

oh 


may  be  administered  twice  a  day  for  two  or 
three  days;  or  one  grain  of  calomel  may  be 
given  over-night  and  followed  by  a  mild 
saline  purgative  in  the  morning. 

A  hot  foot-batli  containing  one  or  two 
table-spoonfuls  of  mustard  reduces  arterial 
tension,  and  this  will  be  found  to  be  a 
valuable  remedy  in  cases  of  severe  throbbing 
pain.  Ten  to  fifteen  grains  of  pulvis  ipeca- 
cuanhae  co.  taken  in  hot  water  at  bed-time 
will  promote  diaphoresis.  If  the  pain  is 
severe  and  continuous  ^  gr.  doses  of 
morphine  sulphate,  or  ten  minims  of  liquor 
of  morphme  bimeconate,  may  be  adminis- 
tered every  two  hours. 

Quinine  is  often  administered  as  a  tonic 
to  these  patients,  in  two-grain  doses.  b 

2.  CHRONIC    LOCAL    PERIODONTITIS 

Chronic  local  periodontitis  is  an  inflam- 
mation of  less  intensity  than  acute  periodon- 
titis, affecting  only  one  or  two  teeth. 

Aetiology.  —  Chronic  periodontitis  may 
originate  from  any  of  the  causes  that  give 
rise  to  acute  periodontitis  but  in  less  severe 
form,  or   it   may    remain    after   an   acute 


of  the  tooth,  an  ill-fitting  denture,  an  Ul-fitting 
crown  (see  Fig.  543)  or  bridge,  the  rough  edge  of 
a  fillmg,  nibber  bands  used  m  regulating  teeth, 
separating  teeth  for  filling,  rubber-dam  clamps, 
a  cavity  lodging  food  at  the  gingival  margin,  and 
the  careless  use  of  a  toothpick.  It  may  occur 
in  teeth  whose  root-canals  have  been  surgically 


Fig.  5i3. — Chi'onic   periodontitis  set  up  by  irritation 
arising  from  a  badly  fitted  cap  crown. 

attack  has  run  its  course.  The  most  common 
cause  is  septic  infection  from  the  root-canals  of 
the  tooth. 

It  may  be  brought  about  by  a  blow,  cold, 
the  presence  of  tartar  or  a  ligature  at  the  neck 


Fig.  544. — Longitudinal  section  from  an  upper  molar  root 
showing  chronic  inflammation  of  the  adherent  perio- 
dontal membrane.  Prepared  by  Weil's  process. 
X   56. 

D,  Dentine ;  C,  Cementum ;  P,  Thickened  periodontal 
membrane  ;    B,  Dilated  blood  vessel. 

treated,  but  in  which,  owing  to  a  bend  in  a 
root  or  to  the  mmuteness  of  a  canal,  the  root 
has  not  been  filled  completely ;  or  it  may  be  due 
to  the  extension  of  a  root-fiUmg  beyond  the  apex 
of  the  root. 

Imperfect  occlusion  may  also  be  cited  as  a 
cause  of  chronic  local  periodontitis,  and  this 
may  be  the  result  of  the  natural  movement  of 
teeth,  or  be  due  to  fiUings  that  have  not  been 
properly  shaped.  Impaction  of  teeth  should 
also  be  mentioned  as  one  of  the  causes  (see  Figs. 
553,  554). 

Pathology. — As  the  result  of  a  small-celled 
infiltration,  the  periodontal  membrane  becomes 
swollen,  injected,  considerably  thickened,  and 
covered  with  patches  of  lymph ;  and  the  bone 
surrounding  the  tooth  is  eiilarged.  The  changes 
that  follow  will  depend  upon  the  activity  of  the 


492 


process.  Where  the  injury  is  slight,  prolifera- 
tion and  calcification  of  the  comiective  tissue 
occurs — Productive  Periodontitis.  If  the  in- 
tensity of  the  injury  is  greater,  the  calcified 
tissues  become  absorbed — Rarefying  Perio- 
dontitis. If  infection  takes  place  and  the  injury 
is  such  as  to  lead  to  the  formation  of  pus. 
Chronic  Suppurative  Periodontitis  is  the  sequel. 
These  tjiree  conditions  are  dealt  with  further  on 
in  this  chapter. 

In  many  cases  of  chronic  periodontitis  there 
is  no  sign  of  the  formation  of  an  abscess  or  even 
of  swelling  in  adjacent  gum  tissue,  though  pus 
may  be  found  along  the  necks  of  the  teeth  at  the 
gingival  spaces. 

Wlien  an  abscess  does  occur  the  sac  is  usually 


Fig.  545. — Productive  periodontitis.  JRiglit  half  of  mandible  showing  third 
lower  molar  with  thickened  and  curved  roots.  (Figure  lent  by  M.  H. 
Crver,  and  Illustrated  in  Kibk's  Text-book  oj  Operative  Dentistry.) 


found  attached  near  to  the  apex  of  the  root.  In 
some  cases  of  chronic  periodontitis  a  thick  mass 
of  granulation  tissue  is  found  attached  to  the 
tooth,  and  to  this  the  term  "  granulome  "  has 
been  apf)lied. 

Tooth-root  cysts  containing  epithelial  tissue 
have  also  been  called  "  granulomes  ",  but  since 
they  originate  from  epithelial  remnants  of  the 
tooth-germ  and  represent  an  early  stage  in  the 
development  of  a  dental  cyst,  they  should  be 
grouped  with  tooth  tumours. 

Signs  and  Symptoms.  —  Teeth  affected  with 
chronic  periodontitis  give  rise  to  periodical 
soreness,  which  lasts  for  two  or  three  days  and 
then  passes  off,  to  return  again  after  a  short 
interval.  In  a  modified  degree  the  symptoms 
may  be  similar  to  those  occurring  in  acute  in- 


flammation. The  tooth  is  tender  to  pressure, 
and,  in  consequence  of  the  thickening  of  the 
membrane,  if  tapped  with  a  light  steel  instru- 
ment, it  gives  a  duller  percussion  note  than  a 
healthy  tooth. 

The  gum  surrounding  the  tooth  may  appear 
quite  normal,  or  be  swollen  and  of  a  dusky  red 
colour;  when  squeezed,  a  small  amount  of  pus 
is  sometimes  found  at  the  cervix  of  the  tooth. 
If  due  to  some  septic  irritant,  the  trouble  will 
last  as  long  as  the  cause  remains  and  may 
continue  for  months,  or  even  for  years. 

Treatment. — The  early  treatment  of   chronic 
local  periodontitis  depends  upon  the  discovery  of 
the  cause  and  its  removal  where  this  is  possible. 
The    question    of    extraction    must    also    be 
considered,  and  if  the  tooth 
is  likely  to  remain  a  con- 
stant  source    of    irritation, 
immediate    removal   is    the 
best  course  to  adopt.    Teeth 
that   have   undergone   con- 
siderable   absorption,    that 
are  hopelessly  loose,  or  those 
with    sinuses    that    do    not 
clear    up,    should    be    con- 
demned. 

In  cases  where  the  inflam- 
mation is  due  to  such  con- 
ditions as  malocclusion,  the 
rough  edge  of  a  filling, 
ligatures,  or  tartar,  the 
removal  of  the  cause  and 
the  aiDplication  of  a  counter- 
irritant  and  anodyne  lini- 
ment may  effect  a  cure. 

Where  an  infected  pulp- 
cavity  is  responsible  for  the 
mischief,  the  canals  must 
be  carefully  opened  up, 
cleansed  with  antiseptics, 
and  thoroughly  syringed ; 
one  or  two  dressings  of 
tricresol  and  formalin  (in 
equal  parts)  should  then  be  used  to  sterilize 
the  tract.  A  certain  number  of  cases  of  chronic 
local  periodontitis  occur  in  devitalized  teeth 
whose  23ulp-fillings  for  one  reason  or  another  are 
not  serving  their  purpose.  In  all  such  cases 
where  the  tooth  is  savable  the  root-filling 
should  be  removed  and  the  canals,  after  being 
cleansed  and  as  far  as  possible  made  sterile  by 
means  of  antiseptic  drugs,  should  be  refilled. 

PRODUCTIVE  PERIODONTITIS 

Productive  Periodontitis  denotes  an  abnormal 
excess  in  the  growth  of  the  cementum  of  one  or 
more  teeth.  The  following  terms  have  been  also 
applied  to  this  condition  :  exostosis,  proliferative 
periodontitis,     h3rpercementosis,    excementosis, 


493 


and  hyperplasia  of  cementum ;  but  the  term 
Productive  Periodontitis  conveys  a  more  accu- 
rate impression  of  the  tnie  patliology  of  the 
condition.  It  is  a  consequence  of  chronic  local 
periodontitis  of  low  degree,  and  is  associated 
with  constitutional  or  local  irritation  of  the 
periodontal  membrane.  Any  irritation  that  in- 
duces a  morbid  activity  of  the  cellular  elements 
of  this  membrane,  and  especially  an  iiritation 
that  increases  the  blood-supply,  will  act  as  a 
predisposhig  cause  of  this  condition. 

Amongst  the  general  causes  that  stimulate 
such  an  activity  are  drugs  (such  as  mercury  and 
iodine),  and  uric  acid,  by  favouring  the  deposit 
of  urates  in  the  membrane  ;  it  should  also  be 
noted  tliat  some  writers  state  tliat  inheritance 
influences  the  formation  of  adventitious  cemen- 
tum. For  the  most  part,  however,  cases  arise 
directly  from  septic  infection  spreading  through 
the  root-canal  of  the  affected  tooth,  the  death  of 
the  pulp  leading  to  an  increase  in  the  blood- 
supply  to  the  periodontal  membi'ane.  Root- 
fillings  projecting  from  the  apex  of  a  tooth,  non- 
occlusion,  malocclusion,  impaction,  and  over- 
use of  a  tooth  in  biting  hard  substances,  are  all 
potential  causes,  while  the  accumulation  of  tartar 
at  the  neck  of  a  tooth,  and  fillings  with  projecting 
or  rough  edges,  will  l)e  found  responsible  for  some 
cases.  Again,  productive  periodontitis  is  often 
associated  with  gutta-percha  fillings  that  extend 
to  the  gum  marghi.  Fig.  545  is  an  excellent 
example  of  productive  periodontitis  in  a  third 
lower  molar  that  had  been  impacted. 

It  is  very  difficult  to  say  when  the  formation 
of  the  cementum  ceases  to  be  physiological  and 
becomes  pathological.  The  tissue  is  formed 
mtermittently,  being  added  layer  after  layer, 
and  for  some  time  after  the  eruption  of  a  tooth 


which,  in  the  process  of  calcification,  become 
embedded  in  the  matrix.  Local  thickenings 
of  a  single  lamella  liave  been  oliserved,  «here  an 


Fig.  54G. — Producti\  u  pLiiudoutuin.      A  ^ucond  upper 
molar  showing  roots  united  by  cementiun. 

consists  only  of  a  few  lamellae  deposited  on  the 
surface  of  the  dentine.  The  layers  are  pene- 
trated by  fibres  of  the  periodontal  membrane, 


D 


.  ■  ^f  ^.  \ 

^ '  '■■i 

■^, 

:L^*-v''!?i 

^1 

1 


KiG.   547. — Chronic    periodontitis.     I'lioto-micrograph 

of  a  premolar  root  showing  "  iuostosis  ". 
C,  Tliickened  Cemeiitmn ;    I),  Dentine ;    A,    Cemental 

tissue      invading      the      dentine      ("  Inostosis  "). 

X  60. 

unusually  strong  bundle  of  periodontal  fibres 
is  required  to  support  a  tooth  against  some 
special  strain. 

The  first  change  that  takes  place  is  that  of 
expansion  of  the  periodontal  membrane,  usually 
the  result  of  some  slight  irritation.  The  mem- 
brane becomes  more  vascidar  and  coated  with 
exudation,  and  this  condition  is  followed  by  an 
increased  activity  of  the  cells.  If  the  irritation 
continues,  organization  into  fibrous  tissue 
occurs,  and,  given  favourable  circumstances, 
ossification  follows.  \^lien  the  j^rocess  spreads, 
and  adjacent  teeth  become  affected,  contiguous 
or  other  roots  may  be  surrounded  and  united 
by  the  inflammatory  exudation.  This  may 
result  in  the  fusion  of  the  roots. of  the  teeth  (as 
in  Fig.  546)  or  tlie  condition  may  extend  so  far 
as  to  cause  fusion  of  the  cementum  with  the 
alveolar  process.  If,  however,  the  degree  of  irri- 
tation changes,  it  may  lead  to  absorption  both 
of  the  cementum  and  of  tlie  dentine  within,  and. 


494 


in  the  area  so  absorbed,  cementum  may  be  re- 
deposited  later.  In  cases  of  another  type,  which 
will  be  described  more  fully  later,  the  apex  of  a 
root  may  be  denuded  by  absorption,  and  nearer 
the  neck  of  the  tooth  a  rmg  of  exostosis  may  be 
found  surrounduig  the  root.  These  processes 
require  many  months,  usually  years,  to  develop. 
The  microscopical  character  of  the  new  tissue 
formed  in  the  roots  has  been  carefully  investi- 
gated by  Douglas  Caush  (7),  (8),  (9).  The 
tissue  is  similar  to  ordinary  cementum  except 


Fig.  548. — Chronic  periodontitis.  Piioto-micrograph 
of  an  upper  molar  root  affected  by  chronic 
periodontitis.  The  root-canal  has  been  invaded 
by  lacunae,      x  22  J. 

D,  Dentine;  C,  Thickened  cementum;  L,  Cemental 
lacunae  in  root-canal;    I,  "  Inostosis." 

that  the  lacunae  are  coarser,  larger,  and  closer 
together,  and  when  a  thick  layer  of  tissue  is 
formed,  it  is  frequently  penetrated  by  vascular 
canals.  The  lamellae  are  thick, and  the  incre- 
mental lines  of  Salter  well  marked.  The  micro- 
scopical appearance  known  as  "  Inostosis  "  was 
first  described  by  J.  Bruch  (4)  of  Leipzic,  some 
forty  years  ago,  and  referred  to  by  him  as  "  a 
penetration  of  the  cementum  into  the  dentuie, 
or  body,  of  the  tooth  ".  This  is,  in  reality,  a 
variety  of  productive  periodontitis  (or  exostosis, 
as  it  was  formerly  called),  differing  from  the 


common  type  m  that  it  is  preceded  by  absorption, 
and  is  to  be  regarded  as  a  growth  of  cementum 
in  a  cavity  formed  by  the  absorption  of  the  den- 
tine (see  Fig.  547).  George  Henry  (16),  in  a  jjaper 
read  before  the  Odontological  Society  m  1871, 
described  in  detail  this  form  of  "  exostosis  ".  He 
attributed  it  to  the  effect  of  local  changes  oc- 
curring in  chronic  periodontitis,  and  considered 
it  to  be  rather  in  the  nature  of  a  tissue  of  repair 
than  of  a  morbid  enlargement  of  the  cementum. 
Furthermore,  it  has  been  observed  in  chronic 
periodontitis  that  the  cemented  tissue  not  only 
penetrates  the  dentine  from  the  surface,  but 
sometimes  invades  the  root-canal,  and  lacunae 
have  been  demonstrated  in  this  canal  at  some 
distance  from  the  apex  of  the  root.  Fig.  548 
shows  the  root  of  a  molar  tooth -N^hose  puljD  had 
been  so  invaded  by  lacunae,  and  Fig.  549  shows 
a  more  highly  magnified  picture  of  a  few  of  these 
lacunae.  In  some  cases  (and  this  has  been 
specially  noticed  in  teeth  which  have  been  trans- 
planted or  replanted)  true  bone  is  formed  in 
the  absorbed  areas.  This  occurrence  of  bone 
in  some  instances,  and  of  cementum  in  other 
instances,  is  explamed  by  the  fact  that  the 
periosteum  of  the  bone  and  the  periodontal 
membrane  are  both  situated  between  the  teeth 
and  the  alveolar  walls. 

The  two  distinct  vital  processes  of  deposit 
and  absorption  appear  to  be  antagonistic,  but 
their  coincidence  can  be  explained  by  the  type 
and  degree  of  irritation  working  at  different  places 
at  the  same  time.  During  tlie  eruptive  period, 
or  after  eniption,  the  bony  partition  between 
the  teeth  may  disappear  and  the  pericementum 
become  united.  This  condition  has  been  called 
concrescence,  or  false  gemination,  and  is  a  form  of 
productive  periodontitis.  The  united  teeth  show 
signs  of  proliferation  of  cementum  at  jjoints 
other  than  the  site  of  union.  At  times  the  roots 
of  one  tooth  undergo  fusion  and  concrescence 
(see  Fig.  546).  The  form  in  which  productive 
periodontitis  affects  the  teeth  will  depend  upon 
the  activity  of  the  process  that  leads  to  its  gro\\th. 
Wlien  the  irritation  is  continuous,  but  of  a  mild 
type,  the  adventitious  mass  may  be  diffused 
over  the  whole  root,  producing  a  smooth  surface  ; 
but  if  the  condition  alternates  between  a  produc- 
tive and  a  rarefying  periodontitis,  as  so  often 
happens,  the  root  will  present  an  irregular  outline. 
The  cementum  may  be  deposited  as  one  or  more 
distinct  nodules,  or  be  localized  at  the  ape.x. 
In  other  cases  it  forms  a  ring,  which  completely 
encircles  the  root.  The  surface  may  be  hard, 
smooth,  polished,  and  translucent,  or  opaque 
and  mottled ;  and,  as  has  been  seen,  the  process 
may  continue  to  spread  until  two  or  more  roots 
of  a  tooth  are  entirely  enclosed  iir  the  tissue, 
and  sometimes,  when  the  roots  of  adjacent  teeth 
become  affected,  the  bone  between  the  roots 
is  absorbed  and  the  roots  of  the  two  teeth  are 


495 


fused  together  by  tlie  cemeiitum.  The  enlarge- 
ment of  the  root  is  always  located  where  hyper- 
aemia  has  been  produced. 

The  symptoms  are  similar  to  those  that  occur 
in  other  forms  of  chronic  periodontitis.  In 
many  instances  the  condition  exists  ^^•ithout  any 
active  local  manifestation  and  may  not  be 
suspected.  Not  infrequently  it  happens  that 
patients  with  this  complaint  suffer  no  incon- 
venience. Sometimes  the  only  sign  is  a  slight 
congestion  of  the  gum,  but  in  most  cases  there 
is  soreness,  elongation  of  the  tooth,  and  a 
disposition  to  grind  the  teeth  together;  at 
other  times  tenderness  on  percussion,  and  (if  the 
pulp  is  alive  and  the  trouble  is  near  the  apex  of 
the  tooth)  signs  of  inflammation  of  the 
pulp  may  be  found.  When,  through 
apical  exostosis,  the  nerves  to  the  pulp 
become  compressed,  the  pain  will  be 
greater.  Paroxysmal  gnawing  pain,  last- 
ing for  some  time  or  recurring  at 
intervals,  has  been  described  as  char- 
acteristic of  the  condition. 

Neuralgia  is  often  caused  by  diseases 
of  the  periodontal  membrane  ;  the  pain 
is  usually  located  in  the  affected  tooth, 
but  it  may  be  referred  in  these  cases  to 
the  eyes  or  to  a  remote  part  of  the  head 
or  face.  Pressure  upon  the  nerves  of 
the  periodontal  membrane  by  hyper- 
trophic growth  is  supposed  to  be  the 
cause  of  the  pain,  and  it  is  stated  that 
cases  of  tri-facial  neuralgia,  functional 
blindness,  functional  deafness,  chorea 
and  epUeptic  fits,  have  been  cured  by 
the  removal  of  "  exostosed "  teeth. 
Seventy-five  per  cent  of  the  teeth 
affected  occur  in  the  back  of  the  mouth, 
and  they  are  found  usually  in  adult  or 
aged  people. 

The  diagnosis  of  this  condition  may 
be  a  matter  of  difficulty,  and  is  often 
only  reached  by  a  process  of  exclusion. 
(See  Chapter  XXVI.)  Pain  or  uneasiness 
of  the  teeth  not  referable  to  any  other  cause 
is  often  successfully  attributed  to  productive 
periodontitis.  Chronic  disease  of  the  periodontal 
membrane  may  lead  to  changes  that  are  more 
marked  in  the  surrounding  tissues  than  in  the 
tooth  itself.  The  \\Titer  was  recently  consulted 
by  a  middle-aged  lady  ^\•ho  complained  of  pain 
in  a  lower  molar,  which  had  been  recently  treated 
and  capped  with  a  collar  cro\^ii.  The  root-canals 
had  been  carefully  cleaned  out  and  filled,  and  the 
crown  itself  was  a  well-fitting  one ;  but  the 
dull  gnawing  continuous  pain,  associated  with 
a  localized  enlargement  of  the  alveolus  and  gum 
around  the  root,  led  to  a  diagnosis  of  productive 
periodontitis,  which  proved  to  be  correct  when 
the  tooth  was  extracted  a  few  days  later. 

The   introduction  of   X-rays   has   made   the 


recognition  of  this  condition  much  easier,  and 
in  most  cases  a  radiograph  serves  to  clinch  the 
diagnosis. 

The  only  certain  method  of  curing  productive 
periodontitis  is  to  extract  the  tooth,  and,  if  the 
pain  is  severe  and  persistent,  or  if  the  tooth 
becomes  a  source  of  constant  annoyance,  it  is 
essential  to  adopt  this  course.  Special  care  is 
necessary  in  extraction,  since  the  enlargement  of 
the  root  causes  it  to  be  wedged  in  the  socket,  and 
there  is  considerable  risk  of  fracturing  the 
root  and  leaving  the  remnant  behind.  Imme- 
diate relief  from  pain  is  not  always  obtained 
when  the  tooth  has  been  extracted,  but  it 
usually  abates  in  a  few  days.     As  a  palliative 


Fig.  5-49. — Photo-micrograpli  of  laciuiao  found  in  the  canal  of  the 
root  sliown  in  Fii;.  548.      X  800  times. 


measure,  the  use  of  jDotassium  iodide  to  be 
taken  internally  has  been  recommended,  and 
as  a  local  counter-irritant  the  follo^^'ing  ^Jigment 
may  be  applied  to  the  gum — 

Tinct.  Aconiti     j 

Tinct.  lodi  -  Partes  aequales,  gij. 

Sp.  ChloroformiJ 

Amputation  of  the  apex  of  the  root  has  been 
suggested,  but  this  procedure  has  little  to 
recommend  it. 

Anchylosis. — Anchylosis,  or  SjTiostosis,  has 
been  defined  as  "  solid  osseous  union  between 
roots  of  teeth  and  their  containing  alveolar 
sockets  "  (9). 

Although  anchylosis  of  teeth  to  the  jaws  is 
common,   and   indeed   normal,   amongst   many 


496 


fish  and  reptiles,  it  is  exceedingly  rare  in  the 
human  subject.  Authentic  cases  of  this  con- 
dition have  only  been  recorded  within  the  last 
twelve    or    fourteen    years.     It    \^'as    formerly 


Fig.  550. — Anchylosis  of  two  upper  imilars  tu 
the  bone  of  tlie  jaw. 

thought  that  a  union  between  the  teeth  and  the 
jaw  could  not  take  place,  but  this  ^\as  a  fallacy. 
The  anatomical  relationship  between  a  tooth  and 
its  socket  corresponds  m  ith  the  anatomical  rela- 
tionship of  the  bones  of  a  joint,  and  in  the  case  of 
a  joint,  or  of  two  contiguous  bones,  it  is  known 
that  anchylosis  may  occur,  the  intervening 
capsule,  ligaments,  cartilage,  and  periosteum 
disappear,  and  the  two  surfaces  of  bone 
become  united  by  osseous  tissue.  In  the  year 
1898,  Storer  Bennett  (b)  demonstrated  from 
a  specimen  in  his  possession  that  anchylosis 
did  occur  in  teeth,  and  he  was  able  to  sho^^• 
a  section  through  a  root  of  a  tooth  closely 
embraced  by  bone,  with  which  at  parts  it  was 
intimately  blended.  Fig.  551,  from  a  section 
prepared  by  A.  Hopewell-Smith,  demonstrates 
a  similar  condition. 

Anchylosis  is  one  of  the  results  of  chronic 
inflammation  of  the  periodontal  membrane. 
It  has  also  been  suggested  that  certain  con- 
stitutional troubles,  such  as  rheumatism  or  gout, 
may  act  as  predisposing  causes.  J.  A.  Woods 
(i)  describes  a  specimen  that  he  removed  from 
the  region  of  the  second  and  third  lower  molars, 
where  the  mass  weighed  2'56  grammes  and 
measured  19  mm.  antero-posteriorly  and  13  mm. 
in  the  linguo-buccal  direction.  The  surface 
was  irregular,  lobular  in  some  places,  deeply 
pitted  in  others.  There  was  a  pumice-stone 
appearance  on  the  inferior  surface,  and  foramina 
penetrated  the  tissue  in  various  places. 

The  pathological  changes  that  take  place  in 
cases  of  anchylosis  may  be  compared  to  those 
occurring    in    joints.     After    repeated    attacks 


of  inflammation,  suppuration  ensues,  the 
periodontal  membrane  is  eventually  destroyed, 
and  a  thick  layer  of  granulation  tissue  takes 
its  place.  Both  the  cementum  and  the  bony 
alveolus  become  permeated  by  inflammatory 
products,  and  a  rarefying  periodontitis  occurs, 
making  inroad  into  the  bone  as  well  as  into  the 
cementum.  Granulation  tissue  enters  and  fills 
the  irregular  spaces  so  made,  the  layers  unite,  and 
fibrification  follows ;  finally,  the  mass  becomes 
ossified,  ^^•ith  the  result  that  the  calcified  matter 
extends  throughout  the  tissue  and  unites  the 
tooth  to  the  bone  of  the  jaw,  so  that  it  becomes 
practically  impossible  to  say  where  one  tissue 
ends  and  the  other  begins.  Fig.  552  taken  from 
a  specimen  in  the  collection  of  G.  W.  Watson  {h) 
shows  the  microscopical  appearance  in  a  case 
of  anchylosis  of  the  roots  of  a  lower  molar  to 
the  jaw. 

The  bone  of  attachment  in  these  cases  is  of  loose 
cancellous  texture,  full  of  irregular  spaces,  and  in 
many  respects  differs  from  normal  bone.  The 
cementum  generally  is  thickened.  Outside  is 
found  a  rough  form  of  bone  fused  to  the  cemen- 
tum, but  it  contains  no  regular  Haversian  system. 
External  to  this  again  comes  the  true  bone  of  the 


Fig.  551. — Aucliylosis.  Vertical  sectiuii  uf  the  radi- 
cular portion  of  a  human  premolar  aiichylosed 
to  the  jaw.  Prepared  by  decalcification,  stained 
with  hacmatoxylene. 

R,  Root  o£  tooth;  B,  Bone  of  jaw.  X  10.  {Photo- 
graph by  permission  of  A.  Hopewell-Smith.) 

jaw ;  but  there  is  no  definite  line  of  demarcation 
between  the  layers  of  tissue,  and  no  trace  of 
the  periodontal  membrane  is  to  be  seen  in  the 
affected  area.  A  great  number  of  lacunae,  large 
in  size  and  irregular  in  shape,  may  be  seen  under 


497 


tlie    microscope.     The   canaliculi   vary   in   size 
and  in  arrangement. 

Anchylosis  ■nill  render  extraction  of  the  teeth 


Fn;.   5o2. — Aiiuhykwis   ul     tliL-   roots   ot   a  human  mandibular  molar. 

Prepared  by  grinding,  mistained. 

A,  Abscess  cavity  ;   O,  Osseous  tissue ;   R,  Roots  of  teeth.      X    1 2. 

(Photo-micrograph  by  'permission  of  A.  Hopewell-Smith.) 


(d)  GiBBS,  J.  H.     Brit.  Dent.  Jour.,  1906,  Vol.  XXVII, 

p.  1 106.     Right  Lower  Molar. 

(e)  Hopewell-Smith,  A.  Denial  Histology  and  Patko- 

Histology,  pp.  393-8. 

(/)  Lloyd -Williams,  E.  Brit.  Dent. 
Jour.,  1893,  Vol.  XIV.  Right 
Upper  Second  Premolar; 

{g)  Rice,  E.  C.  Burchard's  Dental 
Pathology,  p.  57-4.  Case  of  Re- 
plantation of  an  Upper  Premolar 
which  became  firmly  fixed  to  tlie 
jaw. 

(/()  \V.\TSON,  G.  W.  Dental  Record., 
1901,  Vol.  XXI,  p.  160.  Lower 
Molar. 

((■)  Woods,  J.  A.  Brit.  Dent.  Jour., 
1906,  Vol.  XXVII,  p.  348.  Dental 
Anchylosis  in  region  of  Third 
Lower  Molar,  man  aged  60. 


Rarefying   Periodontitis 

(Ab-sorplioii  :  Rarefying  Perice- 
mentitis ;  Ke.<iorption  of  the  Boots  of 
Teeth).— It  should  be  noted  that 
by  the  terms  aljsoi'ption  or  resorp- 
tion of  the  roots  of  the  permanent 
teeth,  or  in  other  words  rarefying 
periodontitis,  is  meant  the  gradual 
destruction  of  tlie  cementum  and 
dentine  by  pliagocytic  cells  occur- 
ring in  the  adjacent  soft  tissue. 

This  condition  is  a  result  of 
cluonic  inflammation  of  the  perio- 
dontal membrane,  and  is  brought 
about  by  an  irritation  greater  than 
that  which  leads  to  productive 
periodontitis.  It  may  be  set  up 
by   the    impaction    of    one   tooth 


more  difficult  to  accomplish.  It  has 
also  a  bearing  upon  the  operation  of 
replantation  and  transplantation.  In 
rei^lantation,  under  favourable  cu'ciim- 
stances  where  the  periodontal  mem- 
brane is  still  living,  the  circulation 
may  be  re-established ;  but  if  the  perio- 
dontal membrane  has  been  seriously 
affected  or  destroyed,  experience  has 
shown  that  it  is  impossible  to  obtain 
a  restoration  of  the  circulation.  The 
fixation  of  such  teeth,  when  it  occurs, 
is  the  result  of  rarefaction  and  the 
redeposition  of  bone  into  the  cavities 
so  formed  and  into  the  space  that 
intervenes  between  tlie  tooth  and  the 
supporting  alveolus  (/). 

SUMMARY  OF  CASES  OF  ANCHYLOSIS 

(a)  Amoedo,  O.  Brit.  Dent.  Jour.,  1895, 
Vol.  XVI,  p.  249.  Anchylosis  of  a 
Second  Temporary  Molar. 

(6)  Bennett,  Sturer.  Trans.  Odont.  Soc, 
Vol.  XXXI,  p.  14.     Lower  Molar. 

c)  Choquet,  M.     Paris. 


Fio.  553. — Rarefying  periodontitis.  Model  of  .the  left  side  of  a 
mandible  showing  the  second  molar  impacted  between  the 
first  and  third  molars. 


1898-9, 


against  another,  and  occurs  sometimes  in  an 
upper  lateral  incisor  at  the  time  of  eruption  of 
the  canine,  or  in  the  distal  root  of  a  second 


498 


molar  through  impaction  of  the  third  molar. 
For  the  most  part  absorption  is  caused  by  chronic 
apical  abscess,  and  occurs  frequently  in  instances 
where  root-fillings  or  broaches  have  been  allowed 
to  reanain  protruding  beyond  the  apex  of  a  tooth. 


Fig.  554.  —  Kanfyint;  ijiiiodnntil  is.  Sliowing  the 
condition  of  tlie  second  lower  molar  in  Fig.  553 
after  extraction. 

A  foreign  body  in  contact  with  the  root  may 
also  lead  to  absorption. 

The  operations  of  Replantation,  Transplan- 
tation, and  Implantation,  of  teeth  are  usually 
followed  by  a  rarefying  periodontitis,  which 
may  extend  over  the  entire  root  of  the  tooth. 
Partial  displacement  resulting  from  a  blow 
or  fall,  and  malocclusion,  are  also  causes  of 
this  condition,  while  in  some  cases  no  definite 
local  cause  can  be  assigned,  the  root  becoming 
absorbed,  apparently,  as  a  result  of  some  obscure 
reaction  of  the  surrounding  tissues. 

To  the  naked  eye  the  appearance  of  the 
lesions  will  depend  upon  the  severity  of  the 
process  and  the  position  in  which  absorption 
occurs.  When  the  irritation  has  been  slight, 
continuous,  and  affecting  the  ajiex  of  the  tooth, 
the  root  is  usually  rounded  and  moderately 
smooth.  When  the  process  has  acted  upon 
different  parts  of  the  root  at  the  same  time  (as 
is  the  case  with  many  replanted  teeth),  the 
surface  will  be  rough,  irregular,  jagged,  and 
covered  with  pits.  In  the  more  acute  cases, 
sharp  edges  remain,  and  what  has  been  described 
as  "  needle-point  absorption  "  can  be  felt  and 
seen.  Cementum  is  fu'st  removed  and  then  the 
dentine,  whilst  in  rare  cases  the  entire  root 
may  disappear.  An  example  of  very  extensive 
rarefaction  is  seen  in  Fig.  555 ;  here  the  trouble 
appears  to  have  started  from  the  irritation  by  a 
root-filling.  W.  D.  Miller  (21)  showed  several 
cases  of  unerupted  and  ovarian  teeth  where 
absorption  had  been  mistaken  for  caries. 

The   condition  of   rarefying   periodontitis   is 


similar  to  the  absorption  of  bone,  and  to  absorp- 
tion of  the  deciduous  teeth.  In  each  case, 
whether  physiological  or  pathological,  it  is 
accomplished  by  means  of  osteoclast  cells. 
True  physiological  absorption  seems  to  act 
more  rapidly  when  the  pulp  of  the  tooth  is  alive, 
but  in  pathological  absorption  the  process  is 
more  rapid  in  pulpless  teeth,  though  in  the  case 
of  necrosed  roots,  the  process,  in  consequence 
of  an  alteration  in  the  character  and  function  of 
the  absorbing  organ,  ceases  to  act.  It  should 
also  be  observed  that  the  tissue  around  a  live 
pulp  is  usually  more  resistant,  and  absorption 
may  extend  in  such  a  manner  as  to  leave  the 
pulp  enclosed  in  a  thin  tube  of  dentine.  Again, 
if  the  process  becomes  more  chronic,  rarefying 
periodontitis  may  change  into  a  productive 
periodontitis;  and  this  fact  accoiints  for  the 
frequency  with  which  both  these  conditions  are 
found  in  the  same  root. 

Adami  has  shown  that  substances  which  in 
small  amounts  stimulate  the  cells  and  lead  to 
increased  growth,  may  in  larger  amounts  become 
toxic  and  lead  to  degeneration  of  the  tissues. 
So,  in  cases  of  absorption,  where  the  intensity 
of  the  injury  is  greater  than  that  which  causes 
productive  periodontitis,  cell  infiltration  as  well 
as  cell  proliferation  occurs. 

In  a  microscopical  section  cut  to  include  the 
affected  tooth  and  the  periodontal  membrane, 
a  series  of  semilunar  depressions  are  seen. 
These  are  called,  after  their  investigator, 
"  Howship's  lacunae."     Their  appearance  under 


Fig.  555. — Rarefying  periodontitis.  Extensive  ab- 
sorption of  the  root  of  an  upper  central  incisor. 

the  microscope  is  as  though  cucular  pieces  had 
been  punched  out  of  the  edge.  In  contact  mth 
this  surface  is  a  newly  formed  tissue  rich  in  cells, 
to  which  the  name  "  absorbent  organ  "  has 
been  given.  This  tissue  appears  to  be  identical 
with  that  which  is  found  in  the  physiological 
absorption  of  deciduous  teeth,  and  in  physio- 
logical and  pathological  absorption  of  bone. 
Situated    in    the    semilunar    depressions,    just 


499 


referred  to,  are  large  egg-shaped  multinucleated 
cells  (osteoclasts,  myeloid  cells,  or  giant-cells) ; 
whilst  the  membrane  shows  a  small-celled  infil- 
tration with  fibrous  tissue  outside  it.  Fig. 
556  shows  a  section  of  a  tooth  affected  by 
rarefying  periodontitis.  Of  the  three  dental 
tissues,  only  one  can  be  replaced,  after  removal 
by  absorption,  viz.  cementum ;  and  this  may 
even  become  deposited  inside  the  pulp  cavity 
when  the  apex  has  been  enlarged  (see  Figs.  548 
and  549). 

At  first,  the  chief  symptom  is  pain  and 
tenderness  on  percussion;  as  the  process  con- 
tinues the  tooth  becomes  loose,  whilst  the  pulp 
and  gum  may  be  congested. 

Usually  the  pulp  of  the  tooth  is  dead,  but 
where  it  is  still  living  it  will  be  hyperaemic 
and  will  give  increased  response  to  thermal 
changes.  In  some  cases  the  discomfort  is  very 
slight,  and  the  condition  is  only  recognized 
by  a  peculiar  and  progressive  looseness  of  the 
tooth,  which  may  be  accompanied  by  a  change 
in  colour.  In  other  cases,  and  specially  where 
impaction  of  teeth  leads  to  absorption,  a  live 
pulp  may  be  exposed,  and  in  these  instances 
acute  pain  will  almost  certainly  follow.     With 


The    prognosis    in 
favourable,    and    if 


advanced    cases    is    un- 
after    careful    root-canal 


Fig.  556. — Rarefying  periodontitis.     Section  of  a  molar  tooth  under- 
going rarefaction  with  the  "  absorbent  organ  "  in  situ. 
A,  Area  invaded  by  rarefaction  process ;   B.  Multi-nucleated  cell ; 

C,  Connective  tissue  ;  D,  Dentine,    x   60.    (Section  prepared  by 

Ernest  B.  Dowsett.) 


X-rays  the  condition  can  usually  be  demon- 
strated clearly,  and  thus  an  accurate  diagnosis 
be  made. 


Fig.  557. — Necrosis  of  a  tooth  commencing  at  the 
apex  and  spreading  towards  the  neck. 

treatment  for  a  few  days  the  con- 
dition shows  no  improvement,  the 
tooth  should  be  extracted. 

Necrosis  of  Teeth.^ — Necrosis  is  a 
term  appUed  to  calcified  tissues  that 
have  undergone  absolute  and  per- 
petual arrest  of  nutrition.  Wlien  the 
vitality  of  a  tooth-pulp  has  been 
destroyed  it  is  customary  to  refer  to 
the  tooth  so  affected  as  dead,  but  the 
term  is  incorrect.  The  tooth  may 
not  be  wholly  dead ;  its  cementum 
may  for  a  long  time  retain  orgamc 
connections  with  the  living  tissues 
outside  it  by  means  of  the  peri- 
odontal membrane ;  and  it  is  only 
when  the  nourishment  has  been 
completely  cut  off  from  the  perio- 
dontal membrane  as  well  as  from 
the  pulp  that  a  tooth  can  be  said  to 
be  dead. 

Necrosis  of  teeth  is  one  of  the 
results  of  suj)purative  i^eriodontitis, 
and  in  its  later  acute  phases  the 
blood-vessels  may  become  obstructed 
by  embolus,  thrombus,  or  detritus. 
The  condition,  however,  is  subject  to 
important  modifications,  which  will 
be  found  to  be  dependent  upon  the 
extent  to  which  the  tooth  is  involved. 
ConnDlete  necrosis  of  teeth  is  occa- 
sionally met  with,  but  partial  necrosis  is  the 
more  common  condition  (see  Fig.  557).  Many  a 
pulpless  root  becomes  discoloured,  and  suffers  a 


500 


certain  amount  of  necrotic  loss  of  the  periodontal 
membrane,  and  yet  remains  in  position  because 
the  membrane  has  not  been  wholly  destroyed. 
In  other  cases,  one  root  of  a  double-rooted  tooth, 
or  one  or  two  of  a  treble-rooted  tooth,  may 


Fig.  558. — Total  necrosis  of  a  lower  molar. 

necrose  and  be  completely  detached  from  the 
membrane  lining  the  adjoining  alveolus,  whilst 
the  other  root  (or  roots),  maintains  its  vital 
connection.  Such  teeth  may  give  rise  to  con- 
siderable discomfort  in  mastication  and  when 
taking  hot  or  cold  fluids  into  the 
mouth.  In  the  early  stage  the 
surface  of  the  root  is  smooth  and 
shows  a  light  grey  to  black  dis- 
coloration (see  Fig.  558).  Later, 
exudation  occurs  between  the  inner 
layer  of  the  periodontal  meml^rane 
and  the  tooth,  and  the  cementum 
is  left  bare.  The  surface  of  the  root 
is  rough  and  discoloured,  the  rough- 
ness being  due  to  the  stripjiing  off 
of  the  membrane  and  to  absorption. 
Wliere  the  membrane  remains  de- 
tached for  some  time,  tartar  may 
be  deposited.  In  cases  of  complete 
necrosis  the  tooth  acts  as  a  foreign 
body  and  is  exfoliated. 

Sometimes    the    necrosed    tooth 
retains    its    position    without    any 
considerable  local  disurbance,  whilst 
in  other  cases  there  is   great    irritation.^  The 
sole  treatment  is  extraction. 

3.  GENERAL    PERIODONTITIS 

Under  this  heading  are  iiicludetl  those  cases 
of  periodontitis  in  which  a  large  number,  or  all, 
of   the   teeth   in   the    mouth   are   affected,   and 


where  there  is  association  with  some  general 
or  constitutional  condition.  Chronic  Suppur- 
ative Periodontitis,  more  commonly  known  as 
"  Pyorrhoea  Alveolaris,"  is  dealt  with  later. 

Aetiology. — ^General  Periodontitis  may  arise 
from  certain  constitutional  causes,  such  as  gout, 
"  rheumatism,"  diabetes,  tuberculous  affections, 
syphilis,  and  scurvy ;  or  may  be  due  to  drags  like 
mercury,  iodine,  and  arsenic.  At  one  time  the 
fumes  of  phosphorus  were  a  common  cause  of 
a  general  periodontitis,  which  usually  ended  in 
necrosis  of  the  jaw.  The  trouble  arises  in  those 
exposed  to  the  fumes  of  phosphorus  where  teeth 
are  unsound,  and  it  commences  in  the  periodontal 
membrane.  The  abandonment  of  the  use  of 
yellow  phosphorus  for  making  matches,  together 
with  the  introduction  of  special  rules  in  the 
factories  of  this  country,  has  brought  about  such 
a  change  that  cases  arising  from  this  cause  are 
rarely  seen  at  the  present  day.  General  peri- 
odontitis may  follow  the  exanthematous  fevers 
or  influenza.  The  pathological  changes  are 
similar  to  those  taking  place  in  chronic  local 
periodontitis,  except  that  they  involve  a  larger 
number  of  teeth.  Li  cases  associated  with 
gout  and  rheumatism  the  exudations  are  liable 
to  become  organized  into  new  tissue.  Other 
cases,  like  those  due  to  tubercle,  diabetes,  and 
phosphorus,  may  go  on  to  suppuration. 

Clinical  and  post-mortem  exiDerience  tend  to 
show  that  gout  and  rheumatism  bring  about 
changes  in  the  fibrous  structures  of  the  body 
and  specially  affect  the  synovial,  periosteal, 
and  periodontal  membranes. 


A 
Fig.  559. — General  periodontitis — Rarefaction. 
A,  Second  right  upper  molar,  distal  aspect.    B,  Second  left  upper  molar, 
distal  aspect.      (Photographs  by  permission  of  A.  Hopewell- Smith.) 

In  gouty  periodontitis  there  is  commonly  a 
history  of  hereditary  gout.  The  teeth  are  well 
formed  and  for  the  most  part  free  from  caries, 
but  show  marks  of  attritioii.  The  margin  of 
the  gum  is  thick  and  congested,  but  there  are 
no  deep  pockets,  nor  is  there  much  calculus, 
though  pus    may  exude   at  the  necks  of  the 


501 


teeth.  The  trouble  commonly  asserts  itself  be- 
tween tlie  ages  of  thirty-five  and  fifty,  and  as 
the  patient  gets  older  the  attacks  become  more 
fi-equent.  In  the  "  rheumatic  "  type,  acute 
tootliaclie  is  often  an  early  indication,  but  the 
inflammation  only  i  caches  the  stage  of  conges- 
tion. Swelling  and  suppuration  rarely  occur. 
General  diffuse  periodontitis  of  a  mild  form 
often  precedes  an  acute  attack  of  gout  or 
rheumatism.  Like  the  so-called  "  rheumatic 
arthritis  "  it  is  greatly  affected  by  climatic 
conditions. 

Some  years  ago  Magitot  described  a  form  of 
periodontitis  that  he  considered  to  be  typical 
of  diabetes,  and  Pavy  in  his  \\ork  on  diabetes, 
says  :  "  The  teeth  are  not  infrequently  observed 
to  become  loosened  in  diabetes,  and  it  may  be 
even  to  such  an  extent  as  easily  to  drop  out. 
There  is  evidently  some  direct  connection  be- 
tween this  phenomenon  and  the  disease.  It 
seems  as  if  the  morbid  condition  of  the  system 
prevailing  interferes  ^^■ith  the  nutritive  action 
going  on  in  the  fang  and  its  socket,  and  so  leads 
to  the  result." 

'"It  is  only  when  the  symptoms  are  allowed 
to  run  on  in  a  severe  form  that  it  is  noticed, 
and,  supposing  the  teeth  to  have  become  already 
loosened,  the  wTiter  has  known  them  to  become 
firm  agam  upon  the  disease  being  controlled 
by  treatment." 

In  young  people  of  tuberculous  tendencies, 
an  injury  to  the  jaw  may  start  a  periodontitis, 
which  is  liable  to  suppurate,  and  in  most  cases 
ends  in  necrosis.  The  mandible  is  specially 
affected. 

Large  doses  of  mercury  will  affect  the  teeth 
and  their  membranes  very  much  as  phosphorus 
does,  and  free  salivation  is  a  constant  char- 
acteristic. 

Li  general  periodontitis  so  brought  about  the 
teeth  become  tender,  elongated,  and  loose, 
and  the  breath  is  tainted  with  a  mercurial 
foetor.  If  the  administration  of  the  drug  is 
continued  sloughs  will  form  on  the  inflamed 
parts,  and  portions  of  the  alveoli  and  the 
contained  teeth  -will  be  lost.  Children  between 
five  and  ten  years  seem  to  be  siJecially  sus- 
ceptible. 

A.  Hopewell-Smith  (17)  describes  a  very 
remarkable  case  of  general  periodontitis,  oc- 
curring in  a  man  aged  forty-four  and  associated 
with  absorption  of  the  teeth.  The  aetiology 
was    difficult    to    determine,    but    the    trouble 


appears  to  have  started  in  the  first  lower  molar 
and  sjjread  to  all  the  other  molars  in  the  mouth. 
They  all  became  affected  by  rarefying  peri- 
odontitis. Two  of  these  teeth  are  shown  in 
Fig.  559. 

J.L.P. 


(1) 
(2) 


(3) 

{*) 
(5) 


(6) 
{-!) 
(8) 
(9) 
(10) 

(11) 
(12) 
(13) 
(14) 


(15) 
(16) 


(H) 

(18) 

(19) 

(20) 

(21) 

(22) 

(23) 
(24) 


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Abkovv,  J.     Diagnoxtik  (Jer  Zahnkrankheiien. 
Black,  G.   V.     Force  in  Mastication  in  Relation 

to  the  Strength  and  Health  of  the  Periodontal 

Membrane.     Operative  Dentistrt/,  Vol.  I,  p.   161. 
Brooks,  H.  R.  F.    "  Inostosis."    Brit.  Dent.  .Jour.. 

1900,  Vol.  XXI,  p.  657. 
Bruch,  J.     Lehrbuch  der  Zahnheilkunde,  Leipzig. 
Buckley,    J.     B.       "  The    Treatment    of     Peri- 
cementitis."      Johnson's    Operative     Dentistry, 

p.  335. 
BuKCHAHD.       Text-book     of     Dental     Pathology, 

pp.  459-522. 
Caush,  D.  E.      "  Exostosis."     Trans.  Odont.  Soc, 

1890-1,  Vol.  XXIII,  p.  225. 
Caush,     D.     E.      "  Exostosis."     Dental     Record, 

July  and  August,  1896. 
Caush,   D.   E.      "  Exostosis."     Brit.  Dent.  .Jour., 

March,    1897,  Vol.  XVIII,  p.    144. 
CoLYER,    J.    F.     Dental    Surgery    and    Patliologij, 

3rd  ed.,  pp.  549-83. 
DowsETT,  E.  B.      "  General  Exostosis  of  all  the 

Maxillary    Teeth."     Proc.    Roy.    Soc.    of    Med. 

(Odont.  Sec),  April,  1912.  p.   107. 
Endelman,  Julio.      "  The  Predisposing  Causes  of 

Periodontitis."     Dental   Cosmos,  August,   1905, 

Vol.  XLVII,  p.  938. 
Endelman,    Julio.      "  The    Pathology  of    Peri- 
cemental Inflammation."     Dental  Cosmos,  3\i\y, 

1907,  Vol.  XLIX,  p.  695. 
FiSHBTjRN,  W.  A.      "  Hypercementosis  and  Neur- 
algia."     Dental  Cosmos,  July    1903,  Vol.  XLV, 

p.  538. 
Heath,  C.     "  Injuries  and  Diseases  of  the  Jaws." 
Henry,    George.     "  Inostosis   as    a   Variety    of 

Exostosis."     Trans.    Odont.   Soc.,    1891-2,   Vol. 

XXIV,  pp.  47  et  seq. 
Hopewell-Smith,  A.      "  Morbid  Affections  of  the 

Alvcolo-periosteum."     Dental      Histology      and 

Pathology,  p.  511-31. 
Hopewell-Smith,  A.     "  Extensive  Absorption  of 

Teeth."      Proc.  Boy.  Soc.  of  Med.  [Odont.  Sec.), 

November,  1909. 
Inglis,    Otto.      "  Diagnosis    of    Pulp    and    Peri- 
cemental Diseases."    Dental  Cosmos,  Sept.  1909, 

Vol.  LI,  p.  1008. 
Marshall,   J.    S.     Operative   Dentistry,   3rd   ed., 

pp.  447-568. 
Miller,  W.  D.      "  Absorption  simulating  Caries." 

Dental  Cosmos,  1905,  Vol.  XLVII,  p.   1153. 
Olson,  M.  W.    "  The  Cause  of  Hypercementosis." 

Dental  Review,  1907. 
Tomes  and  Nowell.     Dental  Surgery. 
Woods,    J.    A.      "  Absorption    with    Deposit    of 

True    Bone."     Brit.    Dent.    Jour.,     1908,    Vol. 

XXIX,  p.  917. 


CHAPTER    XXX 


DISEASES   OF   THE   PERIODONTAL   MEMBRANE   {continued) 


4.  CHRONIC    SUPPURATIVE    PERIODONTITIS 

The  name  Pyorrhoea  Alveolaris,  by  which 
the  conditions  inchided  under  the  above  title 
are  commonly  known,  implies  any  pus-discharge 
from  the  alveolus ;  therefore,  if,  on  pressure 
being  applied  to  the  gum  over  the  apex  of  a 
tooth  and  carried  towards  the  gum  margin, 
pus  is  squeezed  out,  then  the  condition  must  be 
one  of  "pyorrhoea",  and  is  after  all  merely  a 
symptom  that  is  present  in  several  diseases. 
The  condition  often  termed  "  pyorrhoea  alveo- 
laris "  is  more  aptly  and  correctly  called 
Chronic  Suppurative  Periodontitis.  This  title 
does  not  include  those  inflammatory  conditions 
of  the  periodontal  membrane  that  are  un- 
accompanied by  pus  formation.  Many  authori- 
ties have  included  them  under  the  term  "  pyor- 
rhoea alveolaris  ",  although  they  should  really 
be  regarded  more  as  predisposing  causes,  which 
if  untreated  may  lead  to  suppuration,  and  to 
conditions  rightly  embraced  by  the  title 
Chronic  Suppurative  Periodontitis.  The  latter 
term  also  excludes  those  diseases,  such  as 
alveolar  abscess,  that  are  characterized  by  a  dis- 
charge of  j)us,  which,  however,  were  of  neces- 
sity included  in  the  unscientific  class  Pyorrhoea 
Alveolaris. 

Clinical  Types. — -Clinically  there  are  two 
distinct  types  of  chronic  suppurative  peri- 
odontitis— 

(1)  Those  cases  in  which  there  is  apparently 

710  local  exciting  cause.  i 

(2)  Those  cases  in  which  there  is  apparently 

some  local  exciting  cause. 

There  are  two  classes  under  the  latter 
heading — 

(a)  Where  one  or    two    teeth  alone  are  in- 

volved, and   those   to   a  great  extent,  | 
the  pockets  sometimes  extending  nearly 
to  the  apices. 

(b)  Where   all   the   teeth   are    more    or   less 

affected,  some  being  further  uivolved 
than  others,  but  the  pockets  not  being 
particularly  deep. 

In  the  first  type,  i.  e. — 

Where  there  is  apparently  no  local  exciting 
cause,  the  gums  appear  to  be  normal  or  only 


slightly  inflamed  immediately  around  the  necks 
of  the  teeth.  They  may  have  receded  some- 
what. In  some  cases  the  recession  is  marked 
and  the  gums  may  even  have  an  anaemic, 
"  trimmed  down  "  appearance,  with  a  shiny 
glazed  surface.  Pressure  upon  the  gums  im- 
mediately over  the  roots  causes  some  pus  to 
exude  at  the  gum  margin.  Examination  by 
means  of  a  probe  mdicates  pockets  of  no  great 
depth  between  the  teeth  and  gums,  and  also 
shows  absence  of  calcareous  deposits.  The  teeth 
are  not  decidedly  loose,  but  may  have  become 
spaced,  although  at  one  time  normally  close 
together.  The  patient's  breath  may  have  an 
objectionable  odour.  The  progress  of  this  type 
is  generally  slow  and  is  probably  due  to  some 
constitutional  disorder,  which  affects  the  alveo- 
lar process,  leading  to  its  absorption,  which 
may  be  followed  by  bacterial  infection. 


Fig.  500. — Sliowiiig  exposed  root. 

Li  the  second  type,  i.  e. — 

Where  there  is  apparently  some  local  exciting 
cause,  in  those  cases  where  one  or  two  teeth 
alone  are  affected  (class  a) ,  the  gums  are  very 
inflamed  along  the  Ime  of  the  roots.  The  probe 
discloses  deep  pockets  (sometimes  extending 
almost  the  whole  length  of  the  roots)  from 
which  pus  can  be  squeezed.  There  may  or  may 
not  be  calcareous  deposits,  but  in  the  majority 
of  cases  they  can  be  detected.  The  teeth  are 
loosened.  In  some  cases  the  socket-wall,  gum, 
and  periodontal  membrane  may  be  all  con- 
siderably resorbed,  and  the  root  exposed  for  a 
considerable  depth  (see  Fig.  560).  In  such  a 
case  the  pus  is  readily  washed  away  by  the 
saliva,  so  that  the  flow  is  not  very  noticeable 
and  the  neighbouring  gum  is  not  much  inflamed. 

In  those  cases  where  aU  the  teeth  are  more 


502 


503 


or  less  affected  (class  b)  in  the  early  stages  of 
the  disease  the  gum  is  only  slightly  inflamed 
(see  Fig.   561)  and  at   first   only  interstitially. 


hr:0r 


Fig.  561. — Early  stage  of  disease,  showing  gum 
slightly  inflamed  and  thrown  into  a  ridge  around 
molars'  and  premolars. 

The  pockets  are  shallow  and  yield  pus  on  pres- 
sure. There  may  be  slight  deposits  of  calculus 
within  the  gum  margm,  and  the  teeth  are  firm. 


Fig.  502.  —  Later  stugo  of  disease  showing  marked 
absorption  of  tissue  interstitially  and  calcareous 
deposits. 

The  breath  is  normal,  and  the  patient  is  often 
quite  unaware  of  the  existence  of  the  disease. 
As  the  disease  progresses  the  gum  around  the 


Fig.  503. — Adsanced  stage  of  disease  showing  ab- 
sorption of  sockets,  spacing  of  the  teeth,  heavy 
calcareoiis  deposits,  and  pericemental  abscess 
over  left  lateral  incisor. 


necks  of  the  teeth  becomes  congested  and 
readily  bleeds.     The  teeth  are  embraced  by 
rings    of    calculus    and    are    slightly    loosened 
(.see  Fig.  562).    In  later  stages  the  gum  is  mark- 
edly hyperaemic,  there  are  extensive  deposits 
of    hard   greenish-brown    calculus   around    the 


necks  of  the  teeth,  from  which  the  gum  and 
alveolar  process  have  receded,  often  to  the  ex- 
tent   of    disclosing    the    bifurcation    of    multi- 


FiG.  564. — ^Recession  of    gum  from  the  necks  of    the 
teeth.     (J.  Lewin  Payke.) 

rooted  teeth.  The  pockets  are  deeper  and 
the  teeth  loosened  and  sometimes  raised  in 
their  sockets,  thus  still  further  irritatmg  the 
tissues  that  support  the  roots.  Pericemental 
abscesses  may  form,  through  infection  of  the 
deeper  parts  of  the  socket  (see  Fig.  563).  The 
patient's  breath  has  a  sickly  sour  odour,  and 
there  is  mabUity  to  masticate  properly  owing 
to  pain  on  attempted  use  of  the  teeth. 

Aetiology. — The  causes  of  chronic  suppurative 
periodontitis  are  at  present  very  vaguely  under- 
stood, some  writers  attributing  the  disease  to 
Constitutional  Disorders,  whilst  others  consider 
it  to  be  due  to  Local  Irritants.     The  consensus 


Fig.  565.- 


-Recession  of   gum  from  the  necks  of    the 
teeth.     (J.  Lewin  Payne.) 


of  opinion  seems  to  favour  the  belief  that  both 
play  an  important  part, 

The  aetiology  of  the  disease  may  be  considered 
under  tliree  headings. 


504 


1.  Predisposing   Causes. — These    are — 

(a)  Local  conditions,  such  as  spacing  of 
the  teetli  or  the  presence  of  conically 
shaped  teeth,  which  allows  food  to 
collect  between  the  teeth  and  to  be- 
come pressed  down  on  to  the  gum 
margin,  thus  injuring  it  and  lowering 
its  resistance  ;  teeth  with  promment 
interlocking  cusps,  which  p)ut  a  great 
lateral  strain  upon  the  tooth  attach- 
ments (18) ;  abnormal  articulation, 
and  modern  methods  of  jsreparing 
food,  leadmg  to  insufficient  masti- 
cation, and  hence  lowered  resLst- 
ance  of  the  tissues  supportmg  the 
teeth. 

(b)  Constitutional  conditions,  such  as 
Bright "s  disease,  diabetes,  non- 
diabetic  acidosis,  and  the  so-called 
uric  acid  diathesis  (9) ;  also  con- 
ditions following  severe  fevers  (7). 
These  general  disorders  affect  the 
blood  supply  and  so  lower  the 
vitality  of  the  tissues. 

2.  Exciting  Catises. — Injury  to  the  gum 
or  periodontal  membrane  involving  a  breach 
of  surface  and  leadmg  to  bacterial  infection. 
Local  irritants,  such  as  decomposing  food ; 
fillings  improperly  finished  at  the  cervical 
marguis ;  badly  adjusted  crowns,  bridges, 
dentures,  or  orthodontic  appliances  ;  foreign 
bodies,  such  as  fish-bones  and  ligatures ; 
injury  due  to  clamps,  toothpicks,  etc. ;  and  d 
possibly  salivary  calculus.  Bacterial  invasion 
of  a  specific  nature,  has  been  also  suggested, 
but  no  one  responsible  organism  has  so  far 
been  isolated.  Many  forms  have  been  found 
in  the  pus  from  the  pockets,  those  most 
frequently  occurring  bemg  mentioned  in 
connection  \^ith  vaccine  treatment.  These 
local  causes,  by  irritating  the  periodontal 
membrane,  lead  to  mflammation  of  the 
surroundmg  tissues  and  absorj)tion  of  the 
alveolus,  with  coincident  pus  formation. 

3.  8ustaini7ig  Causes. — The  formation  of 
hard,  greenish-brown  tartar  just  below  the 
gum  margin  and  the  invasion  of  the  pocket 
by  bacteria  and  debris,  possibly  followed 
later  by  extensive  infection  of  the  superficial 
layer  of  the  cementum  of  the  roots,  keep  up 
the  irritation,  and  prevent  the  surrounding 
tissues  from  again  embracing  the  necks  of  the 
teeth. 

Hopewell-Smith  is  of  the  opinion  that  "  pyor- 
rhoea alveolaris  does  not  commence  as  a  gin- 
givitis ",  but  that  "it  is  essentially  dependent 
upon  an  osseous  lesion — an  atrophy  of  the 
bone  " ;  also  that  "  the  disease  is  not  m  its 
earliest  stages  a  rarefying  osteitis  ",  and  that 
"  senimal  calculus  Ls  not  in  itself  sufficient  to 


induce  the  condition  and  may  not  be  associated 
with  it  at  all  as  a  predisposing  or  exciting 
cause  "  (20). 

Kenneth  Goadby  is  of  the  opinion  that  milk 
may  contain  organisms  that  are  the  source  of 
infection  in  this  disease. 

Morbid  Anatomy. — The  examination  of  skulls 
in  ^^liom  the  disease  was  present  shows  that  in 
the  earliest  stages  the  bone  between  the  teeth 
is  principally   affected.     At   a    later  stage   the 


D 


Fig.    565.  —  Vertical    section    tlirougli    cervical    region    of 
molar  of  man,  which  presented  no  symptom  of  "pyor- 
rhoea alveolaris  ". 
A,    Cementum ;     B,    Normal    periodontal   membrane ;     C, 
Normal  bone  ;  D,  Areas  of  decalcification. 

(A.  Hopewell-Smith:  Dental  Cosmos.) 


rest  of  each  socket  becomes  markedly  involved, 
the  loss  of  bone  being  chiefly  between  the  outer 
and  inner  alveolar  plates  (i.  e.  at  the  part  close 
to  the  necks  of  the  teeth) .  leaving  them  standing 
as  ridges,  between  which  and  the  teeth  are  cup- 
shaped  dex:)ressions.  Then  the  whole  of  the 
remaining  portion  of  the  sockets  gradually  be- 
comes absorbed,  the  loss  of  bone  spreading 
towards  the  apices  of  the  teeth  until  finally  the 
latter  fall  out,  having  entirely  lost  their  bony  sup- 
port. Rough  rings  of  tartar  of  a  greenish-brown 
colour  are  seen  around  the  necks  of  the  teeth  : 


505 


and  the  exposed  portions  of  the  cementum 
sometimes  show  dark  brown  stains.  In  some 
specimens  there  seems  to  have  been  a  thickening 
of  the  outer  alveolar  plate.  The  maxilla  is  more 
involved  in  the  disease  than  the  mandible  (7). 

Pathology. — Although  recognizing  that  the 
disease  arises  as  some  disturbance  in  the  tissues 
surrounding  and  supporting  the  teeth,  yet 
authorities  differ  as  to  the  exact  point  at 
which  this  disturbance  commences. 

Kemieth  Goadby  considers  that  it  origin- 
ates as  an  acute  inflammatory  condition  of 
the  gum  margin,  i.  e.  a  simple  gingivitis, 
often  associated  with  great  irritation  of  the 
surrounding  gums,  and  possibly  a  general 
stomatitis.  This  is  followed  by  a  subacute 
suppuration  of  the  gum  margin,  the  loosened 
gums  gradually  separating  from  their  proper 
attachments ;  the  periodontal  membrane  is 
absorbed  and  a  condition  of  rarefying 
osteitis  is  set  up  in  the  surrounding  alveolus. 
At  the  same  time  there  are  nodular  deposits 
upon  the  roots  of  the  teeth.  Salivary 
calculus  may  or  may  not  be  present  at 
any  period  of  the  disease  (15). 

Hopewell-Smith  seems  to  be  of  the 
opmion  that  the  disease  does  not  originate 
as  a  gingivitis,  but  as  an  atrophy  of  the 
bone  due  to  some  disturbance  in  its  vas- 
cular supply,  in  some  cases  following  upon 
constitutional  disturbances,  such  as  acute 
anaemia,  long-continued  fevers,  rheumatism, 
hydrargyrism,  etc.  He  shows  a  section 
through  the  cervical  region  of  a  molar  of  a 
man  of  middle  age,  in  which  the  gum, 
cementum,  and  periodontal  membrane, 
appear  normal,  whilst  decalcification  or 
halisteresis  of  the  free  edge  of  the  osseous 
socket  is  commencing  (21)  (see  Fig.  566). 
He  considers,  and  has  sections  to  show, 
that  not  only  is  the  free  margin  of  the 
bony  socket  absorbed  by  osteoclasts  near 
the  cervical  region  of  the  teeth,  but  also 
the  bone  deep  down  in  the  radicular 
portion,  its  surface  acquiring  an  eroded 
appearance  (20)  (see  Figs.  567,  568.  569). 

The  atrophy  of  the  bony  socket  and  the 
shrinkage  that  follows  it,  lead  to  a  \\idening 
of  the  guigival  margin  and  general  enlarge- 
ment of  the  pockets,  with  hyperplasia  of  the  peri- 
odontal membrane.     If   a  pathogenic   infection 
takes  place,  pyogenic  bacteria  invade  and  settle 
down    in    these    pockets,    and     "  pyorrhoea  " 
results.     Food    and    other    foreign    materials 
collect  in  the  enlarged  pockets  and  lead  to  the 
formation  of  pus.     They  may  possibly  set  up  a 
suppurative    gingivitis,    with    the    production 
of  tartar.     Histologically  there  seems  to  be  some 
change  in  the  oral  epithelium  at  aU  points,  espe- 
cially at  the  periphery,  where  it  has  been  lost  by 
desquamation.     The  gum  has  become  inflamed. 


and  the  cementum  is  somewhat  hyperplasic. 
Singularly  enough  its  peripheral  portions  are 
remarkably  smooth  and  well  defined,  .seldom 
exhibiting  the  foveolae  of  Howship  occupied  by 
large  mycoplaxes,  except  the  cementum  at  the 
apices.  If  it  is  at  aU  hyperplasic,  it  is  accidental 
and  not  a  result  of  "  pyorrhoea  ".  Sharpey's 
fibres  and  their  canals  show  no  signs  of  bacterial 


^ 


^"^^ 


A, 


Fig.  567. — Vertical  section  tlxrough  canine  and  right 
maxilla  o£  man,  aged  twenty-eight,  showing  latest 
stages  o£  extremely  acute  condition  associated  with 
"  pyorrhoea  alveolaris  ".      X   35. 

Apex  o{  root  formed  by  hyperplasic  cementum ; 
B,  Hyperplasic  periodontal  membrane  ;  C,  Sequestrum 
of  bone ;  D,  Osteoclasts  producing  laoimal  absorption 
of  bone  of  socket.  (A.  Hopewell-Smith  :  Dental 
Cosmos. ) 

invasion.  Senimal  calculus  may  or  may  not  be 
present,  but  is  not  sufficient  in  itself  to  induce 
the  condition  (20). 

J.  F.  Colyer  says  "  that  the  initial  stage  is 
characterized  by  the  formation  of  a  stagnation 
area  in  the  normal  sj)ace  around  the  neck  of  the 
tooth.  Infection  with  pathogenic  organisms 
rapidly  follows,  for  even  in  the  early  stages 
organisms  are  present,  that  are  known  to  be 
associated  with  chronic  forms  of  disease  in 
other  parts  of  the  body.  The  stagnation  area 
is    a    septic    focus,    and    destruction    of    the 


506 


attachment  of  the  muco-periosteum  of  the  tooth 
follows.  By  this  process  the  pockets  are  m- 
oreased  in  size,  and  the  periodontal  membrane 
and  the  surrounding  bony  attachments  of  the 
teeth  are  progressively  destroyed.  The  rapidity 
of  destruction  depends  mainly  upon  the  type 
of  infection  and  degree  of  resistance  of  the 
surrounding  tissues.  Li  some  cases  toxins 
from  the  septic  focus  around  the  neck  of  the 


Fig.  568. — Free  mai-giu  ut  etlye  ul  socket  of  labial  surface 

of  same,  x  80. 
A,  Cementiun  ;  B,  Inflamed  periodontal  membrane ;  C,  In- 
flamed gum  tissue ;  D,  Free  edge  of  bone  decalcified 
and  converted  into  fibrous  intervening  tissue ;  E,  Osteo- 
clasts producing  lacmial  absorption  of  external  and 
internal  surfaces  of  bone. 

(A.  Hopewell-Smith  :  Dental  Cosmos.) 


tooth  are  absorbed  by  tlie  periodontal  membrane 
and  "  held  up  "  in  the  tissues  around  the 
apex  of  the  tooth  and  lead  to  inflammation  and 
the  absorption  of  tooth  tissue"  (8). 

With  present  knowledge  it  is  hardly  safe  to 
dogmatize  upon  the  pathological  details  of  the 
disease,  but  the  fact  remams  that  slow  destruc- 
tion of  the  tissues  supporting  the  teeth  takes 
place,  with  the  formation  of  pus,  leading  to  the 
ultimate  loss  of  the  teeth ;  and  with  that  the 
trouble   usually   ceases.     Towards   the   end   of 


the  disease,  when  the  looseness  of  the  teeth  is 
marked,  the  puljis  may  undergo  hyperaemic 
changes  and  die  through  strangulation.  The 
dead  pulps  may  become  infected  and  so  give  rLse 
to  septic  apical  periodontitis. 

Signs    and    Symptoms.  —  These     have     been 
already     indicated     when     dealing     with     the 
clinical   tyjjes.     A  radiograph   of  the   affected 
parts  will  show  the  absorption  of  the  alveolus, 
and  will  be  a  great  help  in  determining  the 
extent  to  which  the  disease  has  progressed. 
In  those  cases  described  as  the  first  type, 
the  patient   will  often  complain  of  rheu- 
matism and  give  a  history  of  the  hereditary 
loss  of  sound  teeth. 

In  cases  of  the  second  type  where  the 
disease  is  markedly  localized,  there  is  some- 
times a  history  of  injury  to  that  part,  such 
as  a  blow,  violent  and  persistent  wedging, 
injury  by  a  fragment  of  bone,  etc. ;  and 
the  case  may  be  complicated  by  the  forma- 
tion of  alveolar  abscess  consequent  upon 
the  death  of  the  pulp. 

Wlien  the  disease  has  been  present  for 
some  time,  the  patient  may  complain  of 
malaise  and  other  general  symptoms,  the 
disease  being  capable  of  producmg  effects 
"ranging  from  gastritis  to  actual  septic 
infection  "  (5,  p.  649). 

A  notable  point  is  the  rare  occurrence 
of  caries  in  the  teeth  of  patients  suffering 
from  chronic  suppurative  periodontitis, 
particularly  in  cases  of  the  first  type. 

Prophylaxis. — For  the  prevention  of  this 
disease  the  great  object  is  the  promotion 
and  maintenance  of  a  healthy  condition 
in  the  mouth  generally.  To  this  end  the 
patient  should  thoroughly  cleanse  the  teeth 
after  every  meal  by  means  of  a  tooth-brush 
of  medium  stiffness,  and  a  non-gritty 
powder.  These  should  be  used  with  a 
rotary  movement — not  du-ectly  across  the 
teeth,  as  that  would  drive  debris  mto  the 
interstitial  spaces,  nor  directly  up  and 
down  as  that  would  tend  to  injure  the 
gum  margin.  The  interstitial  spaces  should 
be  carefully  cleansed  by  the  use  of  a  quUl 
toothpick  or  floss  silk.  The  patient  should 
be  instructed  to  consult  his  dentist  every 
three  months  or  thereabouts,  according  to 
the  rapidity  with  which  tartar  is  deposited, 
when  such  deposits  should  be  removed. 

Gum  massage  three  times  a  day  with  a  hard 
or  medium  brush  has  been  advised,  together 
with  the  use  of  antiseptic  mouth  washes,  such 
as  three  volumes  of  hydrogen  peroxide  with 
4%    boric  acid  (4). 

Some  operators  advise  the  use,  after  every 
meal,  of  an  astringent  mouth  wash,  such  as 
30  grams  of  tincture  of  myrrh  to  15  grams 
of  menthol ;    10  to  15  drops  in  a  wineglass  of 


507 


water  give  tone  to  the  gums  and  increase  the 
power  of  resistance. 

It  is  important  that  the  patient  should  give 
the  teeth  and  thek  iieighbourmg  tissues  sufficient 
exercise  by  the  mastication  of  reasonably  hard 
foods. 

Treatment. — Before  undertaking  the  treat- 
ment of  a  case  of  chronic  suppurative  j)eri- 
odontitis  it  is  advisable  to  explain  to  the  patient 
the  difficulties  to  be  encountered  and  to  what 
extent  a  cure  is  possible.  Various  views 
are  held  concernmg  the  appUcation  of  the 
term  "  cure  "  to  these  cases  of  "  pyorrhoea  ". 
Some  operators  regard  a  case  as  cured  as 
soon  as  the  discharge  of  pus  has  disap- 
peared; others  apply  the  term  to  those 
cases  in  which  the  symptoms  have  been 
absent  for  a  period  of  twelve  months ; 
whilst  again  others  hold  that  a  case  of 
"pyorrhoea"  can  only  be  considered  to 
be  cured  when  all  indications  of  the  trouble 
have  been  absent  for  many  years  without 
any  intermediate  operative  treatment.  It 
seems  that  at  present,  even  under  the  most 
favourable  circumstances,  one  cannot  hope 
for  a  restoration  of  the  tissues  that  have 
been  destroyed  by  the  disease ;  but  with 
careful  treatment  the  pus  discharge  can  be 
checked,  the  tissues  supportmg  the  teeth 
can  be  brought  mto  a  healthy  condition, 
and  with  the  exercise  of  a  little  care  on 
the  part  of  both  patient  and  operator, 
kept  so.  It  entails  frequent  visits  to  the 
dental  surgeon  during  treatment  for  a 
period  possibly  of  months,  the  time,  how- 
ever, depending  upon  the  extent  of  the 
disease.  Even  after  the  disease  has  been  ^ 
arrested  and  the  symptoms  have  dis-  f' 
appeared,  the  patient  should  attend  at 
intervals  of  one  to  three  months  for 
prophylactic  treatment  accordmg  to  the 
needs  of  each  particular  case. 

J.  r.  Colyer  states  that  cases  favourable 
for    treatment    are    those    m    which    the        ^' 
pockets  are  shallow,  the  arch  is  well  de-       ^' 
veloped,  the  power  of   mastication   good, 
and  the   patient  is  a   nasal  breather  and 
gives   indications   of  recuperative   powers. 
This  last   point   is  sho\vn  by  the  condition  of 
the  alveolar  process :  the  presence  of  sclerosis 
of  bone  is  indicative  of  resistance. 
•  Treatment  may  be  of  two  kinds  :  (1)  Local; 
(2)  General. 

Of  whatever  type  the  case  may  be,  attention 
should  first  be  dnected  to  the  local  conditions, 
as  some  cases,  particularly  those  of  the  second 
type,  are  quite  successfully  treated  by  local 
attention  only.  This  shoidd  consist  in  the 
thorough  removal  of  all  local  irritants.  Teeth 
that  are  hopelessly  loose  must  be  so  regarded ; 
for  their  movement,  particularly  during  masti- 


cation, irritates  the  surrounding  tissues  and 
thus  aggravates  the  condition.  Such  teeth 
are  those  having  less  than  a  half  to  a  third  of 
the  root  supported  by  alveolus.  Teeth  that 
are  loose,  but  offer  some  chance  of  cure, 
should  be  supported  by  means  of  a  splint, 
or  Ugatures  to  them  from  the  neighbouring 
firm  teeth.  Many  forms  of  splmt  and  ligature, 
too  numerous  to  describe  here,  have  been 
suggested.     Burchard,  in  his  Text-hook  of  Dental 


Ai.  509. Apiuul  regiun  uf  saiuu,  iiiudi&ii  Scutiuii.        y\   35. 

Apex  of  root  with  hyperplasia  of  cementum  ;  B,  Hyper- 
plasic  periodontal  membrane ;  C,  Alveolar  bone  with 
manyosteo-porotic  spaces ;    D,  Osteoclasts. 

(A.  Hopewell-Smith  :    Dental  Cosmos.) 

Patliology,  deals   with    a   number   of   them   in 
detail. 

Deposits  of  calculus  must  be  removed 
thoroughly.  They  may  be  either  salivary 
deposits  of  a  liglit  browTi  colour,  frequently 
found  upon  the  portions  of  teeth  above  the 
gum  margin,  or  serumal  deposits.  The  former 
are  derived  from  the  saliva,  and  are  regarded 
by  Tomes  as  not  being  responsible  for  the 
condition.  The  latter  are  thought  by  some  to 
come  from  the  blood,  and  to  be  indicative  of  a 
uric  acid  condition.  They  are  of  a  greenish- 
brown  colour  and  are  usually  found  below  the 


608 


gum  margin,  but  in  advanced  cases  they  are 
exposed  to  view  owing  to  the  recession  of  the  gum 
and  alveolar  process.  Considerable  difficulty 
will  be  experienced  in  their  comj)lete  removal, 
as  they  are  very  hard,  and  in  those  cases  in 
which  the  gums  readily  bleed,  are  masked  by 
haemorrhage.  However,  thek  complete  re- 
moval is  essential.  For  this  purpose  many 
and  marvellous  are  the  kinds  of  instruments 
that    have    been  devised,    but    each    operator 


Fig.  571. — Kadiugrapli  sliowiug 
absorption  of  alveolu-s. 

(J.  Lewin  P.iYNE.) 


Fig.  570.  —  Vertical 
left  maxilla  of 
of  comparison. 


section  through  second  incisor  and 
woman  of  twenty-five  for  pixrposes 
X  30.      Patient  unaffected  by  disease 


of  bones.     No  "  pyorrhoea  alveolaris  "  present. 
A,   Apex   of   root;    B,    Periodontal   membrane;    C,    Bone; 
D,  Medullary  spaces  and  tissue.     All  normal. 

(A.  Hopewkll-Smith  :   Dental  Cosmos.) 


will  fuid  by  experience  the  particular  type  by 
which  he  can  best  attain  this  object.  The 
scalers  suggested  by  Lloyd  Williams  and  Gushing 
are  useful,  particiilarly'  for  the  removal  of  the 
bulk  of  the  tartar ;  whilst  Albert  Senn  of  Ziirich 
(26)  and  Younger  have  each  devised  a  set  of 
very  fine  instruments  which  are  particularly 
useful  for  the  clearing  of  the  more  inaccessible 
places,  as  they  can  be  passed  down  to  the  end 
of  each  pocket. 

Wlien  finishing  the  scaling,  Head  (19)  advises 


the  use  of  hychogen  ammonium  fluoride  as  a 
tartar  solvent,  before  completing  the  removal 
of  the  calcareous  deposits.  The  method  of 
application  is  as  follows.  The  pockets  to  be 
treated  are  dried,  and  the  neighbouring  gum  is 
protected  by  means 
of  a  naj)kin.  The 
cb'ug  is  then  apjslied 
under  the  gum,  and 
after  the  lajise  of 
two  or  thref 
minutes  the 
gum  forming 
the  pocket  be- 
comes slightly 
white.  The 
patient  is  then 
instructed  to 
rinse  out  the 
mouth,  and  the 

removal  of  the  tartar  is  not  attempted  until 
the  following  day,  when  it  will  be  found  to 
be  considerably  softened  and  can  be  readily 
removed.  The  hydrogen  ammonium  fluoride 
also  seems  to  have  a  stimulating  effect  upon 
the  gum  so  treated.  The  drug  must  })e  kept 
in  a  special  bottle,  as  it  attacks  ordinary 
glass.  It  is  unwise  to  attempt  the  removal 
(if  all  the  tartar  at  one  sitting.  A  few  teeth 
should  be  treated  at  one  time,  and  those 
that  were  cleared  at  the  previous  visit 
should  be  carefully  inspected,  ui  order  that 
any  jjieces  of  calculus  that  were  overlooked 
may  be  removed.  The  pockets  and  inter- 
dental spaces  are  to  be  flushed  out  with 
hydrogen  peroxide  (vols.  15)  by  means  of  a 
fine-nozzled  syringe  or  atomizer.  These  can 
be  obtained  with  several  nozzles  of  various 
shapes,  which  can  be  detached  for  sterilizing. 
The  force  of  syring- 
ing removes  any 
foreign  body,  such 
as  food,  loose  frag- 
ments of  tartar,  and 
collections  of  pus. 
It  also  distends  the 
pockets,  enabling 
the  operator  to  ob- 
tain a  clearer  view 
of  the  root  surfaces. 
The  removal  of  the 
sub-gingival  calculus  is 
often  accompanied  by 
pain ;  in  that  case  it  is 
advisable  to  inject  no- 
vocaine  or  some  simi- 
lar local  anaesthetic,  or 
cocaine  into  the  pockets, 
in  10  %  trichloracetic  acid  and  packed  into  the 
pockets  for  ten  or  fifteen  minutes  will  enlarge 
them  and  render  the  calculi  more  accessible. 


Fig.     5/2.  —  Kadiograph 
showing    absorption    of 
alveolus. 
(J.  Lewin  Payne.) 

introduce   powdered 
Cotton-wool  soaked 


509 


At  tlie  same  time  it  has  a  softening  effect  upon 
the  deposits,  and  constricts  the  gum  tissue,  so 
lessening  the  haemorrhage.  Salicylized  cotton 
used  in  the  same  way  and  left  for  a  day  will  also 
have  this  effect. 

Riggs  advocated  the  scraping  of  the  alveolar 


a  0  r  d  r 

Fig.  573. — Lloyd-Williams"  small  Scalers. 
{a)  For  "  pull  "  movement;  (6)  and  (c)  right  and  left 
"  pull  "  instrmnents  with  extra  long  reach : 
{d)  and  (e)  spoon  chisels  cutting  on  three  edges — 
may  be  used  either  with  "  pull  "  or  "  push  " 
movement.  (Messrs.  Claudius  Ash,  Sotis  tfc  Co., 
Ltd.) 

edges  with  scaling  instruments,  in  order  to 
remove  the  diseased  bone  and  promote  the 
formation  of  healthy  tissue,  but  Burchard 
advises  this  only  in  those  cases  that  are  not 
dependent  upon  calculus  formation,  that  is, 
in  cases  of  the  first  type.     It  is  a  very  painful 


Badly  finished  fillings,  especially  at  the  cervical 
edge,  must  be  trimmed  off  or  replaced.  Cro-\viis, 
dentures,  etc.,  that  are  acting  as  local  irritants. 


Fig.  574.  —  Cushing's  fine  Scalers.    (Messrs.  Claudius  Asli, 
Sons  cfc  Co.,  Ltd.) 


process  and  calls  for  the  preliminary  applica- 
tion of  cocaine.  Intense  f)ain  may  follow  this 
treatment  and  for  relief  phenol-camphor  packed 
into  the  pockets  is  very  effective.  It  is  prepared 
as  follows — 


Fig.  575. — Lloyd-Williams' 
small  Scaler  with  metal 
liandle.  (Messrs.  Claiidiu.i 
Ash,  Sons  d:  Co.,  Ltd.) 


Fig.  570. — Harlan's  fine 
Scalers.  (Messrs.  Clau- 
dius Ash,  Sons  dt  Co., 
Ltd.) 


Acidum  Carbolicum  Pure 
Camphora  Trita  . 
Alcohol  Ethylicum    . 


partes  xxx. 
„      Ix. 


X. 


must  be  corrected,  or  non-irritating  substitutes 
put  m  their  places.  It  has  been  suggested  that 
where  resorption  has  exposed  the  bifurcation 
of  molar  roots,  the  bifurcation  should  be  scraped 


510 


and  filled  with  gutta-percha.  One  is  inclined 
to  think  that  however  carefully  the  filling  may 
be  carried  out,  there  is  a  great  possibility  of  food, 
etc.,  collecting  around  it  and  keeping  up  the 
irritation. 

r 


Fig.  577. — Albert  Senn's  Scalers  for  pyorrhoea  treatment. 
Ash,  Sons  ds  Co.,  Ltd.) 

The  teeth  and  pockets  having  been  cleansed, 
the  next  step  is  the  cauterization  of  the  latter. 
For  this  purpose  many  drugs  have  been  advised. 
Atkhison  used  a  paste  made  by  rubbing  together 
equal    parts    of    carbolic    acid 
crystals  and  solid  caustic  potash. 
Chromic  acid,  aqua  regia  or  solid 
chloride  or  iodide  of  zmc,  have 
also  been   recommended.     The 
packing   of    the    pockets    with 
copper  sulphate  has  met  with 
some  success,  whilst  Roughton 
claimed  that  pledgets  of  wool 
dipped  into  a  1  in  2000  corrosive 
sublimate  solution  and  packed 
into  the  pockets  had  a  marked 
and    speedy    beneficial    efiect. 
Aromatic  sulphuric  acid,  25  per 
cent ;  lactic  acid,  full  strength  ; 
or  trichloracetic  acid,   25  to  30 
per   cent,  are  also  useful.     In 
cases  of  local  origin,  applications 
of  tincture  of  iodme  to  the  gums  every  other  day 
help  them  to  shrink  to  a  normal  state.     Some 
operators  hold  that  cauterization  of  the  pockets 
only  produces  temporary  results,  as  the  purulent 


mjection  of  a  bismuth  paste  mto  the  pockets. 
The  paste  consists  of  bismuth  subnitrate  30  per 
cent,  vaseline  60  per  cent,  paraffin  5  per  cent, 
white  wax  5  per  cent,  and  is  made  as  follows  :  the 
vaseline,  paraffin,  and  wax  are  boiled,  and  the 
bLsmuth  subnitrate  is  added 
and  stu-red  in  as  soon  as  they 
are  taken  from  the  flame. 
An  all-metal  syringe  holding 
about  half  an  ounce,  and 
having  a  flexible  tapering 
blunt  point  made  of  pure 
sflver,  platmum,  or  gold,  is 
then  filled  with  the  warm 
paste,  and  the  pockets  are 
injected.  The  syringe  should 
be  warmed  beforehand,  so 
that  the  paste  is  not  chilled 
and  solidified  (3)  (16) 
The  gums  should  be  massaged  by  the  patient 
every  day,  by  passing  the  thumb  or  index 
finger  over  the  position  of  the  roots  of  the 
teeth  from  the  apex  towards  the  cro\\ii.     This 


(Messrs.  Claudius 


Fig.  579. — Fleischmann's  massaging  instrimients,  with  screw  ends 
rubber  points.      (Dental  Manujacturing  Co.,  Ltd.) 


and 


Fig.  578. — Paste  Syringe.     (Messrs.  Claudius  Ash, 
Sons   d:  Co.,  Ltd.) 

condition  recurs  as  soon  as  the  cauterizing  scab  is 
pushed  off,  whilst  others  claim  that  cauterization 
promotes  healthy  granulations.  Several  cases 
have  been  reported  in  which  common  salt  has 
been  used  on  a  brush  and  also  m  the  pockets, 
with  very  good  results.     Beck   advocates  the 


helps  to  express  the  pus  and  stimulates  a  healthy 

circulation.   The  use  of   powdered  sulj)hur   or 

tannic  acid,  with  or  without  glycerme,  whilst 

massagmg,  has  been  suggested.    Some  operators 

prefer   the  use  of  a  brush  or  specially 

constructed  rubber  j)oints  for  massaging, 

as  produced  by  Fleischman  of  Lyons. 

The  cleaning  of  the  teeth,  if  possible 

after  every  meal,  with  an  antiseptic  and 

astringent   is    very   deshable.      The    following 

formula  has  been  suggested  by  A.  B.  Harrower — 


Bi  Magnesii  Carbonatis     . 

Potassii  Tartrat.  Acid.  . 

Cinchona  Rub.  Cort. 

Alum.  Exsiccati     . 

01.  Mcnthae  Pip.    . 

01.  Cinnamom 

01.  Rosae  Geran.  . 

M.  ft.  dentifricium. 

(The    quantities    have   been  reduced    and   slightly 

altered  in  relative  amounts  from  the  original  formula. ) 


o  jss. 
o  ij- 
3  ij- 

5  ij- 
n\xv. 

Tit  XX. 

n\x. 


511 


All  solid  ingredients  are  to  be  finely  powdered, 
the  oils  added  to  the  magnesium  before  thorough 
mixing  of  the  jjowders,  and  the  ■whole  is  to  be 
sifted  through  silk  (5,  p.  646). 

This  should  be  followed  by  an  astringent 
antiseptic  \^ash  forcibly  sprayed  by  an  atomizer, 
or  syi'mge,  into  the  pockets  and  uiter-dental 
spaces,  and  the  treatment  will  have  a  very 
beneficial  effect.  It  can,  of  course,  be  done  by 
the  patient. 

The  devitalization  of  the  affected  teeth  has 
been  advised  by  Baldwm  and  others,  with  the 
object  of  diverting  the  blood  supjjly  from  the 
pulp  to  the  periodontal  membrane.  This  may 
be  quite  sound  treatment  where  the  periodontal 
membrane  is  extensively  involved,  and  there 
is  a  risk  that  the  pulp  may  be  already  affected  ; 
but  otherwise  some  operators  are  rather  adverse 
to  doing  so,  as  root  treatment  is  one  of  the 
most  uncertain  operations  in  dental  surgery, 
and  moreover  a  pulpless  tooth  seems  to  be 
more  subject  to  periodontitis  than  a  normal 
one,  probably,  ho\\'ever,  on  account  of  defective 
aseptic  procedure. 

Hartzell  strongly  urges  the  planing  of  the 
root  surfaces  from  which  the  periodontal 
membrane  has  been  strijjped.  This  should  be 
done  with  instruments  specially  constructed 
to  ensure  accuracy  and  avoid  the  possibility 
of  cutting  too  deeply.  He  argues  that  the 
superficial  layer  of  cementum,  which  contains 
pits  for  the  attachment  of  the  pericemental 
fibres,  becomes  hifected,  these  jjits  harbouring 
bacteria,  which  can  be  destroyed  only  by 
planing  away  the  superficial  layer  of  cementum 
until  the  hard  layer  upon  ^hich  it  rests  is 
reached.  This  is  ensured  by  the  use  of  instru- 
ments capable  of  cutting  to  a  limited  depth. 
The  planing  of  each  tooth  should  be  finished 
at  one  sitting,  as  the  planed  surface  becomes 
sensitive  in  a  few  hours.  As  a  rule  this 
sensitiveness  gradually  disapjiears,  but  may 
occasionally  persist,  necessitating  the  removal 
of  the  pulp.  Greater  recession  of  the  gum 
follows  this  treatment  of  the  root  surface 
and  is  frequently  unfavourably  commented 
upon  by  the  patient.  It  should  be  explained 
that  the  recession  is  due  to  the  shrmkage  of  the 
gum  to  a  healthy  condition  and  is  quite  desirable, 
since  the  depth  of  the  pocket  is  thus  reduced, 
thereby  lessenmg  the  risk  of  recurrence ;  and 
that  the  teeth  are  more  fii'mly  supported  now 
than  before  treatment,  since  the  surrounding 
tissues  are  healthy,  even  though  the  roots  are 
now  exposed  (18).  Hartzell  also  advises  the 
reduction  of  prominent  cusj)s  wherever  possible. 

Many  cases  have  been  successfully  treated 
without  havmg  recourse  to  root-planing,  but 
this  may  be  adopted  with  advantage  in  cases 
that  do  not  yield  to  ordinary  local  treatment, 
since  it  is  quite  possible  that  the  cementum  has 
become  too  deeply  infected  to  be  sterilized  by 


the  medicaments  mtroduced  into  the  pockets. 
Hopewell-Smith  states  that  "  there  are  no 
traces  of  bacterial  mvasion  of  Sharpey's  fibres 
and  their  canals  "  (20)  m  sections  cut  from  the 
Jaw  of  a  patient  who  at  the  time  of  death  was 
suffermg  from  chronic  suppurative  periodontitis. 
However,  it  seems  quite  likely  that  had  the 
I  disease  proceeded  further,  invasion  of  these 
1  canals  would  have  taken  place. 
I  Another  line  of  treatment  that  has  found  some 
warm  supporters  is  the  artificial  production  of 
hyperaemia  in  the  affected  parts.  This  may  be 
brought  about  by  means  of  poultices  or  blisters, 
but  the  method  suggested  by  Bier  .seems  to  be 
the  most  promising.  This  consists  in  the 
construction  of  a  splint,  \\hich  presses  upon  the 
gums  as  far  from  the  crowns  of  the  teeth  as 
possible.  The  splint  has  two  parts,  one  of 
which  is  adapted  to  the  internal,  and  the  other 
to  the  external,  alveolar  plate  and  gum.  These 
are  united  by  means  of  springs  passing  over  the 
crowns  of  the  teeth.  The  pressure  upon  the 
gums  can  be  regulated  by  means  of  these  springs 
and  should  be  sufficient  to  cause  congestion 
without  being  actually  painful.  The  appliance 
should  be  worn  for  about  ten  or  fifteen  minutes 
twice  a  day. 

H.  Woodruff  has  suggested  the  use  of  a 
vulcanite  cap,  which  fits  completely  over  the 
teeth  and  sockets,  graspmg  the  gums  firmly 
around  its  margin,  but  being  away  from  them 
elsewhere.  A  space  is  thus  formed,  which 
communicates  by  means  of  a  tube  ^vith  an 
exhaust  bulb.  The  au-  is  then  withdrawn  from 
the  space  between  the  inside  of  the  splint  and 
the  teeth  and  gums,  and  so  hyperaemia  is  pro- 
duced. The  object  of  forced  hyperaemia  is  to 
increase  the  supply  of  blood  to  the  part,  and 
so  dilute  the  irritants  found  there. 

Where  the  gum  forming  the  pockets  is 
greatly  hyj)ertropliied  some  operators  do  not 
hesitate  to  cut  away  the  gum  tissue,  or  to 
remove  it  by  means  of  caustics  or  the  electro- 
cautery. This  renders  the  pockets  shallower, 
and  they  are  therefore  less  likely  to  retain 
foreign  matter  that  would  cause  a  recurrence. 

If  after  local  treatment  isolated  pockets  still 
discharge,  it  is  wise  to  explore  them  carefully 
m  search  of  any  foreign  material,  particularly 
calculus,  that  has  been  overlooked. 

A  tooth  (or  teeth)  badly  involved  and  dis- 
charging much  pus  should'  be  carefully  tested 
as  to  the  condition  of  its  pulp.  This  may  be 
dead  and  purulent,  and  so  contributing  to  the 
discharge  of  pus. 

The  thorough  sterilization  of  all  instmments 
is  highly  important. 

Ionic  medication  is  a  valuable  method  of 
treatment  fully  described  in  Chapter  XXXI. 

If  local  treatment  on  the  foregoing  Unes 
is  conscientiously  carried  out,  many  cases 
of    chronic    suppurative    jieriodontitis    can   be 


512 


regarded  as  cured.  These  are  usually  cases  of 
the  second  type.  Cases  of  the  first  tyjie  are  less 
hopeful,  and  those  that  have  undergone  thorough 
local  treatment  without  complete  success  call 
for  treatment  on  general  Imes.  This  should 
be  carried  out  in  conjunction  with  the  patient's 
medical  adviser ;  at  the  same  time  the  local 
conditions  must  not  be  neglected.  The  general 
treatment  depends  ujjon  the  nature  of  the 
.systemic  disorder,  and  for  the  most  part  aims 
at  the  "  elimination  of  waste  jjroducts  and 
the  reduction  of  hyperacidity  by  the  use 
of  alkaline  remedies.  The  bowels  should  be 
kept  active  and  the  skin  pores  opien.  Brisk 
exercise  in  the  open  air,  if  not  specifically 
contra-mdicated  by  organic  disease,  is  valuable 
in  both  directions.  Warm  baths  followed  by 
cold  douches  and  vigorous  rubbing  stimulate 
the  skm.  Turkish  baths  followed  by  massage, 
du'eeted  to  the  stimulation  of  the  eliminating 
organs,  are  valuable  unless  contra-indicated. 
Free  drinking  of  jjure  water  increases  the  blood 
pressure  and  flvishes  the  tissues  and  kidneys  " 
(5). 

Of  recent  years  treatment  by  means  of 
vaccines  has  been  tried,  and  in  many  cases  with 
remarkably  good  results.  In  some  quarters 
it  is  not  regarded  favourably,  since  no  case  has 
been  cured  by  vaccines  alone. 

However,  it  is  generally  agreed  that  local 
treatment  must  be  undertaken  in  all  cases, 
even  if  general  treatment  be  carried  out  at  the 
same  time.  The  value  of  vaccuie  treatment  is 
shown  in  certain  cases  where  thorough  local 
treatment  has  faUed  and  yet  the  symptoms  have 
disappeared  after  treatment  with  vaccine.  A 
single  pathogenic  organism  has  not  yet  been 
isolated,  but  the  examination  of  pus  from  a 
pocket  shows  the  presence  of  nearly  every 
morphological  variety. 

According  to  the  observations  of  Eyre  and 
Payne,  the  most  generally  present  are — 

Micrococcus    (staphylococcus)   pyogenes, 
Micrococcus  catarrhalis. 
Streptococcus  pyogenes  longus ; 
Streptococcus  laaceolatus  pneumoniae, 

and  these  may  be  regarded  as  responsible 
bacteria  (11). 

Goadby  has  found  the  following  organisms 
to  occur  most  frequently — 

(1)  In  the  early  stages  : 

Micrococcus  catarrhalis. 

Streptococcus  brevis  (invariably  pre- 
sent) , 

Bacillus  septvis  or  BacUlus  coryza- 
segmentosa. 

Bacillus  necrodentalis ; 

the  two  latter  he  regards  as  essential  in  the  early 
stages  of  the  disease. 


(2)  In  the  latter  stages : 

Streptococcus  pyogenes  longus, 
Micrococcus  catarrhalis. 
Micrococcus  citreus  granulatis  (Freund), 
Streptococcus  aureus, 
Pneumococcus  (15). 

The  vaccine  is  prepared  from  pus  taken  from 
the  pockets  of  the  j)atients'  teeth.  Great  care 
is  exercised  in  obtaining  the  pus,  so  that  organ- 
isms from  other  parts  of  the  mouth  shall  not 
be  included.  The  pus  first  squeezed  from  the 
pockets  is  wiped  away  by  means  of  a  sterile 
swab  and  rejected,  as  this  might  contain  foreign 
organisms,  only  that  which  comes  from  the 
deeper  parts  of  the  pockets  being  used  for 
the  preimration  of  vaccines.  A  culture  of  the 
principal  organisms  present  is  made,  and  is  then 
emulsified  and  transferred  to  a  sterile  test-tube, 
and  killed  by  exposure  to  a  suitable  tempera- 
ture. From  this  emulsion  are  prepared  doses 
containmg  5,  10,  50,  or  100  million  killed 
bacteria.  These  doses  are  injected  into  the 
patient  in  increasing  strengths  at  intervals  of 
about  five  to  fourteen  days,  the  oliject  lieing  to 
increase  the  supply  of  anti-bodies  the  formation 
of  which  seems  to  be  stimulated  by  the  presence 
of  the  dead  bacteria. 

Some  operators  advise  the  extraction  of  all 
teeth  affected  by  chronic  suppurative  periodon- 
titis, particularly  if  associated  with  general 
symptoms,  but  this  seems  hardly  justifiable, 
unless  the  patient  refuses  to  undergo  the  more 
conservative  treatment,  or  this  has  been  con- 
scientiously followed  out  and  has  failed. 

In  the  event  of  extraction  being  resorted  to, 
J.  F.  Colyer  advises  first  the  removal  of  the 
back  teeth,  and  then  the  taking  of  the  bite 
with  the  natural  incisors  and  canines  in  situ. 
By  this  means  one  can  obtain  the  correct 
distance  between  the  two  jaws  and  so  reproduce 
the  natural  bite  exactly.  It  is  also  advisable 
to  take  impressions  of  the  front  teeth  before 
their  removal,  so  that  in  the  construction  of  the 
artificial  denture  one  may  have  some  guide  by 
means  of  which  the  natural  arrangement  of 
the  teeth  may  be  more  accurately  reproduced. 
Dentures  should  be  inserted  as  early  as  possible 
after  the  removal  of  the  teeth  in  order  to 
preserve  the  alveolar  ridge. 

In  conclusion,  the  writer  cannot  help  thinking 
that  different  observers  may  have  studied 
different  types  or  stages  of  the  disease,  and  so 
have  arrived  at  such  widely  divergent  opinions. 

W.A.H. 

BIBLIOGRAPHY 

(1)  Abkovy,  J.     Fulminant  Caries  Alveolaris  Speci- 

fica.     Brit.  Med.  Jour.,  1904,  p.  1371. 

(2)  Beldon,  H.  E.     Porcelain  Splints  in   Pyorrhoea 

Alveolaris.     Dental  Cosmos,  July  1908,  Vol.  L, 
p.  703. 


513 


(3)  Brophy,  T.  W.     Recent  Progress  in  Oral  Surgery.    '    (17) 

Dental  Cosmos,  Dec.  1909,  Vol.  LI,  p.  1384. 

(4)  Brown  (Brussels).      Pyorrhoea  Alveolaris.     Den-    ;    (18) 

tal  Cosmos,  March  1911,  Vol.  LIII,  p.  375. 

(5)  BuRCHARD.      Text-book  of  Dental  Pathology,  Y>.6i\. 

(6)  Carmalt-Jones    and    Humphreys.       Treatment       (19) 

of  Pyorrhoea  Alveolaris  by  Inoculation  with 
Bacterial  Vaccine.  Brit.  Dent.  Jour.,  1908, 
Vol.  XXIX,  p.  63.  ,    (20) 

(7)  CoLYER,  J.  F.  Dental  Surgery  and  Pathology,  p.  5^^. 

(8)  Coi-YER,   J.    F.     The   Treatment  of   Periodontal 

Disease.     Proc.  Roy.  Soc.  of  Med.  (Odont.  Sec.),    ,    (21) 
Feb.  1912. 

(9)  Croftan,    a.    C.     The    Gingival    Manifestations 

of  Certain  Metabolic  Disorders.     Dental  Cosmos,       (22) 
Dec.  1911,  Vol.  LIII,  p.  1365. 

(10)  Endelman,  J.     Uratic  Deposits  upon  the  Roots       (23) 

of  Teeth.  Dental  Cosmos,  Aug.  1905,  Vol. 
XLVII,  p.  935. 

(11)  Eyre,  J.  W.  &  Payne,  J.  Lewin.     Some  Observa-       (24) 

tions  on  the  Bacteriology  of  Pyorrhoea  Alveo- 
laris  and    the    Treatment   of   the   Disease    by 
Bacterial  Vaccine.     Proc.   Roy.   Soc.   of    Med.       (25) 
(Odont.  Sec),  1909,  p.  29. 

(12)  Feiler,  Erich.    Treatment  of  Alveolar  Pyorrhoea. 

Ash's  Monthly,  Jan.  1911.  (26) 

(13)  Fryd,     (Hamburg).      Artificial    Hyperaemia    in 

Dentistry.     Dental  Cosmos,  April  1909,  Vol.  LI,       (27) 
p.  483. 

(14)  Gardiner,  F.  D.     Case  of  Pyorrhoea  of  Lower   !    (28) 

Incisors  and  Canines.    Dental  Cosmos,  A^TiW^ll,       (29) 
Vol.  LIII,  p.  473. 

(15)  Goadby,  Kenneth.    Pyorrhoea  Alveolaris.    Pro- 

gress Report.      Trans.   Odont.  Soc,    April  1902. 

(16)  Goldberg,    H.     A.     Treatment     of     Pyorrhoea   <  (30) 

Alveolaris.     ZJe^fa/ Cosmos,  May  1911,  Vol.  LIII,    1 
p.  551.  I 


Hardgrove,  T.  A.    Pyorrhoea  Alveolaris.     Dental 

Review,  Feb.  1906. 
Hartzell  T.  B.     The  Practical  Surgery  of  the 

Root   Surface   in    Pyorrhoea.     Dental    Cosmos, 

May  1911,  Vol.  LIII,  p.  513. 
Head,  J.     A  Tartar  Solvent  especially  useful  in 

Pyorrhoea  Work.     Dental  Cosmos,  Jan.    1909, 

Vol.  LI,  p.  41. 
Hopewell-Smith,  A.     Pyorrhoea  Alveolaris :  its 

Patho-Histology.     Dental  Cosmos,  April   1911, 

Vol.  LIII,  p.  397. 
Hopewell-Smith,  A.     Pyorrhoea  Alveolaris :  its 

Interpretation.      Dental    Cosmos,    Sept.     1911, 

Vol.  LIII,  p.  881. 
HoRDER,  T.  J.     Pyorrhoea  Treatment  by  Specific 

Inoculation.     Lancet,  Dec.  28,   1907. 
Houston,  I.  F.     Immobilizing  as  a  Cure  for  Pyor- 
rhoea Alveolaris.     Dental  Cosmos,  April  1909, 

Vol.  LI,  p.  445. 
Merritt,  a.     The  Protective  Substances  of  the 
Blood  in  their  Relation  to  Pyorrhoea  Alveolaris. 
Dental  Cosmos,  Jan.  1909,  Vol.  LI,  p.  44. 
PiERGiLi   (Rome).     Massage  and  Bismuth  Paste 

in  Pyorrhoea  Alveolaris.     Dental  Cosmos,  Dec. 

1911,  Vol.  LIII,  p.  1459. 
Senn,   A.     (Ziirich).     On    Pyorrhoea    Alveolaris. 

Ash's  Quarterly  Circular,  June,   1907. 
Sims,    H.     Pyorrhoea    and  Some    Investigations 

into  its  Bacteriology,  1906. 
Tombs  &  Nowell.     Dental  Surgery,  1906,  p.  636. 
Turner,  J.  G.     Some  Clinical  Notes  on  Pyorrhoea 

Alveolaris.     Proc.    Roy.    Soc.    of    Med.   (Odont. 

Sec),  Vol.    1,    1908,   p.    104.     Discussion,   pp. 

105  et  seq. 
Williams,    W.    R.     The   Vaccine   Treatment   of 

Pyorrhoea  Alveolaris.     Dental    Cosmos,    Sept. 

19II,  Vol.  LIII,  p.  1076. 


17 


CHAPTER  XXXI 


DENTAL   ELECTRO-THERAPEUTICS 


NATURE   OF    APPARATUS 

In  order  to  apply  electricity  in  an  intelligent 
manner,  it  is  essential  that  more  than  a  super- 
ficial knowledge  should  be  acquired  of  the  means 
of  production,  the  methods  of  application,  and 
the  effects  obtauiable  by  the  current.  It  is 
beyond  the  scope  of  this  work  to  undertake 
more  than  a  curtailed  description  of  the  par- 
ticular forms  of  electricity  that  concern  the 
dental  practitioner,  but  the  student  of  electro- 
therai^eutics  should  interest  liimself  iiithe  whole 
subject  of  medical  electricity,  a  knowledge  of 
which  will  greatly  enhance  his  capability  of 
dealing  with  this  special  subject  as  applied  in 
dentistry. 

Galvanic  Electricity. — For  dental  purposes  it  is 
necessary  to  have  a  continuous  current  that  can 
be  controlled  at  ^^■ill  and  reduced  to  the  muiimum 
of  electro-motive  force  ;  this  is  obtainable  from 
a  collection  of  cells  or  from  current  dynamos, 
controlled  by  a  rheostat  or  some  form  of  current- 
resistance  in  circuit. 

Primary  Cell. — Of  the  many  forms  of  primary 
cells  that  exist,  those  that  concern  the  dental 
student  most  are  the  Leclanche  for  generathig 
galvanic  current,  and  the  chromic  acid  and  allied 
forms  for  cautery  work. 

The  Lecla7iche' Cell. —The  Leclanche  ceU  con- 
sists of  a  glass  jar  half  filled  with  a  strong 
aqueous  solution  of  ammonium  chloride,  in 
which  is  placed  a  porous  pot  containing  a 
rod  of  carbon  surrounded  by  powdered  carbon 
and  peroxide  of  manganese,  formmg  altogether 
the  "  negative  element  ",  and  a  rod  of  amalga- 
mated zinc,  forming  the  "  positive  element  ". 
The  fluid  m  the  jar  is  the  "  electrol3^e ",  or 
excitant  and  conductor  of  electricity  formed 
within  the  jar.  Thus  the  internal  parts  of  the 
cell  consist  of  a  positive  (+)  and  a  negative  (— ) 
element  and  an  excitant  conductmg  fluid  (see 

Fig.  580). 

Tlie  ammonium  chloride  solution  acts  chem- 
ically on  the  zinc  rod  to  form  zinc  chloride  and  to 
liberate  hydrogen  and  ammonia ;  the  hydrogen 
coOects  at  the  carbon  {— )  element,  uniting  there 
with  oxygen  liberated  from  the  manganese 
peroxide,  to  form  water.  The  formation  of 
zinc  chloride  on  the  positive  element  is  called 
polarization;  and  the  union  of  hydrogen  with 

5 


oxygen  at  the  negative  element,  by  which 
bubbles  of  gas  are  dispersed  instead  of  beuig 
allowed  to  cover  the  surface  and  make  it  in- 
effective, is  called  depolarization. 

No  polarization  takes  place  in  this  form  of 
cell  when  in  disuse,  but  directly  the  circuit  is 
closed  rapid  polarization  takes  place,  in  con- 
sequence of  hydrogen  being  liberated  more 
rapidly  than  the  oxygen  of  the  manganese 
peroxide  is  formed  to  unite  with  it ;  thus  the 
cell  becomes  weak  if  it  is  short-circuited  for  any 
great  length  of  time,   but  it  recovers  rapidly 


Fig.  580. — Leclanche  cell. 

on  the  circuit  being  again  broken,  and  is  con- 
sequently a  very  lasting  form  of  cell. 

The  choice  of  zinc  and  carbon  in  the  con- 
struction of  the  Leclanche  cell  is  based  on 
Volta's  contact  law,  which  points  out  that 
when  two  very  dissimilar  metals  are  brought 
in  contact  through  an  electrolyte,  the  one 
becomes  positively  and  the  other  negatively 
electrifled.  By  this  is  meant,  not  that  two 
kinds  of  current  are  formed  (for  it  should  be 
remembered  that  there  is  only  one  kind  of 
electricity),  but  that  the  difference  of  potential, 


14 


515 


or  electro-motive  force,  is  greater  in  the  one 
(zinc)  than  it  is  in  the  other  (carbon). 

Current. — It  has  been  stated  that  no  current 
flows  when  the  Leclanche  cell  is  not  in  use ;  the 
ends  of  the  carbon  and  zinc  outside  the  cell  are 
called  the  terminals,  and  as  soon  as  the  terminals 
are  connected  by  a  conducting  agent  (copper 
and  silver  wire  being  the  best  conductors)  the 
current  flows  in  the  direction  from  the  +  to  the 
—  element  internally,  i.  e.  from  the  higher 
potential  to  the  lower ;  passing  to  the  terminals 
of  the  —  it  becomes  + ,  and  is  returned  to  the 
+  terminal  forming  a  circuit.  Current  will  thus 
flow  until  equilibrium  is  established,  and  the 


Fig.  581.- 


-Direction  of  flow  of  current  inside  and 
outside  cell. 


cell   is   then   said   to   have    "  run  down "  (see 
Fig.  581.) 

Electro-motive  Force. — The  force  that  causes 
the  current  to  flow  from  the  element  of  higher 
potential  to  the  element  of  lower  potential  is 
termed  electro -motive  force  (E.M.F.).  The 
electroljrte  within  the  cell  is  the  conducting 
medium  between  the  two  producing  elements. 
The  E.M.F.  varies  in  different  kinds  of  cells, 
and  this  variation  depends  on  the  kinds  of 
plates  used  and  the  exciting  fluid.  The  E.M.F. 
of  one  Leclanche  cell  is  said  to  be  1-47  volts,  the 
Daniel  cell  about  1  volt,  and  the  Grenet  or 
bichromate  cell  about  2  volts. 


Units — 

The  unit  of  E.M.F.  Is  one  volt. 

The  unit  of  current  strength  is  one  ampere. 

The  unit  of  resistance  is  one  ohm. 

The  unit  of  quantity  of  current  is  one  coulomb. 

The  unit  of  capacity  is  one  farad. 

These  names  have  been  applied  in  honour  of 
the  great  early  workers  in  electrical  science, 
Volta,  Ampere,  Coulomb,  and  Faraday. 

Resistance. — In  studying  electricity  it  must 
be  remembered  that  resistance  forms  a  very 
important  factor  in  the  production  of  cuiTents ; 
not  only  has  the  resistance  beyond  the  terminals 
(R)  external  to  the  cell  to  be  calculated,  but  also 
the  internal  resistance  (r)  that  the  currents  meet 
within  the  cell  in  passing  from  the  +  to  the  — 
element  through  the  electrolyte. 

The  passmg  of  current  from  the  terminals  of 
the  cell  depends  on  the  nature  of  the  conducting 
medium ;  thus  copper  wire  offers  little  resistance 
to  current  and  is  much  used  as  leads  to  convey 
current,  whilst  Gferman  silver  and  graphite  are 
poor  conductors,  and  advantage  is  taken  of  this 
fact  in  their  use  for  constructing  resistance  in 
circuit  to  reduce  tlie  current  strength.  Glass 
and  many  allied  substances  are  non-conductors 
of  current.  The  resistance  varies  directly  with 
the  length  of  the  conducting  wire  ;  thus  5  metres 
of  wire  wiU  offer  twice  the  resistance  of  2-5 
metres  of  wire  of  the  same  thickness. 

Resistance  of  the  Body. — The  resistance  of  the 
human  body  varies  greatly,  not  only  in  different 
individuals  but  also  in  the  same  individual  at 
different  times ;  it  may  be  noted  tliat  a  patient 
at  one  time  will  permit  5  niilliamperes  of  current 
to  be  conducted  through  tlie  body  without 
noticing  it,  whilst  at  another  time  he  will  object 
to  less  than  half  that  amount.  The  average 
resistance  of  tlie  body  is  said  to  be  over  1200 
ohms.  GuOleminot  says  :  "  Resistance  depends 
on  the  degree  of  polarization  and  number  of  free 
ions  in  the  tissue ;  the  determination  of  the 
resistance  of  the  body  is,  therefore,  a  very 
complex  problem  "  (4,  p.  201). 

Ctirrent  Strength. — The  current  strength  is 
measured  in  amperes,  one  ampere  being  the 
unit.  This  amount  of  current,  however,  is 
more  than  can  be  used  in  electro-therapeutics ; 
it  is  therefore  divided  into  niilliamperes  (toth) 
ampere).  The  various  units  that  have  been 
mentioned  depend  upon  one  another  for  calcula- 
tion of  the  current  in  use.  By  the  application 
of  Ohm's  Law,  which  says,  "  The  current  varies 
directly  as  the  electro-motive  force  and  inversely 
as  the  resistance  in  a  circuit  ",  a  definite  know- 
ledge of  the  different  units  concerned  may  be 
arrived  at.  If  any  two  terms  are  knowai,  say 
(E)  electro-motive  force  and  (R)  resistance,  the 
third  (C),  current  strength,  may  easily  be  found ; 
or  if  (C)  current  strength  and  (R)  resistance  are 


516 


known,  (E)  electro-motive  force  may  be  deter- 
mined. To  calculate  these,  by  working  accord- 
ing to  Ohm's  Law,  an  ordinary  algebraic  calcu- 
lation wiU  give  the  required  factors.  Say,  for 
example,  there  are  18  Leclanche  cells  of  1  volt 
each  passing  a  current  througli  a  patient  with 
a  resistance  of  1500  ohms,  what  amount  of 
current  m  m.a.  will  pass  ? 


C  = 


18  X  1  volt 
1500  ohms 


=  -012  amperes  =  12  m.a. 


So  also,  to  find  the  E.M.F.  of  18  cells  when  the 
other  two  factors  are  knov\n,  resistance  bemg 
1500  ohms  and  current  strength  -012  amperes. 

E.M.F.  =  -012^  X  1500"  =  18  volts. 

Li  like  manner  resistance  can  be  determmed 
when  E.M.F.  and  current  strength  are  known. 

18  V. 
■ -0121 


R: 


1500  ohms. 


These  figures  are  only  taken  as  an  example, 
and  are  not  accurate  as  far  as  the  Leclanclie 


^^^56^^^^^ 


Fig.  582. — Connection  of  voltaic  cells  in  series. 


cell  is  concerned,  for  internal  resistance  (r)  of 
each  cell  must  be  added ;  but  on  this  principle, 
any  two  factors  being  known,  the  third  can  be 
ascertamed.  On  a  thorough  knowledge  of  the 
application  of  Ohm's  Law  in  electro-physics 
depends  the  scientific  use,  and  indeed  the 
successful  use,  of  electric  current  in  electro- 
therapeutics (11). 

Batteries. — The  E.M.F.  obtainable  from  one 
Leclanche  cell  is  insufficient  for  practical  pur- 
poses, and  to  make  the  cell  larger  would  not 
increase  the  E.M.F.,  because  the  increase  of 
current  strength  depends  on  the  kind  of  plates 
and  the  electrolyte  used,  and  not  on  the  size  of 
the  cell.  In  order  to  obtain  sufficient  amperes 
it  is  necessary  to  collect  the  current  from  a 
number  of  cells  by  connecting  them  in  series ; 
this  constitutes  a  battery.  The  most  convenient 
form  of  cell  for  a  battery  is  the  Leclanche, 
either  dry  or  wet  cell.  The  dry  cell  consists  of 
a  zinc  canister,  measuring  3f  x  H  x  H  inches, 
which  forms  tlie  positive  element  of  the  cell. 
This  is  lined  with  a  paste  of  some  composition 


of  ammonium  chloride,  the  exciting  material 
or  electrolyte.  In  the  centre  of  this  is  ihe 
carbon  and  manganese  dioxide,  which  forms  the 
negative  element.  This  cell  is  more  compact 
and  cleaner  than  the  wet  cell,  but  does  not  last 
as  long,  and  cannot  be  renewed.  The  wet  cell, 
already  described,  can  be  renewed,  and  lasts  for 
years  «ith  a  little  attention. 

To  construct  a  battery  take  18  to  24  cells  and 
connect  the  carbon  of  one  with  the  zmc  of  the 
adjoining  one  by  means  of  msulated  wire ; 
repeat  this  until  the  whole  number  are  joined 
in  succession ;  to  the  carbon  of  the  first  cell 
comiect  a  copper  conducting  wire,  which  will  be 
the  -f  pole,  and  to  the  zuic  of  the  last  cell  a 
similar  wire,  which  will  be  the  —  pole  of  the 
now  completed  galvanic  battery  (see  Fig.  582). 
The  current  strength  from  such  a  battery  will 
be  far  m  excess  of  what  can  be  used  in  dental 
electro-therapeutics ;  in  order  to  reduce  it  to 
practical  proportions  a  rheostat  must  be  con- 
nected in  circuit,  and  must  be  of  a  type  that 
will  admit  of  only  a  fraction  of 
a  milhampere  of  current  to  start 
with,  and  be  so  arranged  that 
the  increase  shall  be  exceedingly 
gradual.  Batteries  that  have 
only  current  collectors  attached, 
by  which  one  cell  at  a  time  is 
switched  into  use,  are  not 
adapted  to  many  dental  opera- 
tions, because  the  turnmg  on  of 
each  cell  causes  too  sudden  an 
increase  of  current  and  gives  a 
pauiful  shock,  which  would  make 
some  operations  impossible.  A 
graphite  rheostat  or  volt-selector 
should  be  jjlaced  in  circuit  with 
the  battery,  and  the  current  worked  through  it. 
Rheostats. — Of  the  different  forms  of  rheostats 
for  cell  batteries  those  constructed  of  graphite 
are  the  most  suitable  ;  a  simple  form  is  one  made 
of  lead  pencils  with  a  gliding  metallic  spring,  by 


Siark 


+' 


Schwa  ch. 


M 


Fig.  583. 


+  0    P    G- 

-Graphite  Rheostat. 


{Schall.) 


which  the  finest  graduations  of  current  are 
obtainable  (see  Fig.  583). 

One  of  German  make,  of  graphite  with  mer- 
cury contact,  having  a  resistance  of  100,000 
ohms,  which  can  be  reduced  to  20  ohms  by 
turning  a  glass  dial,  is  a  very  reliable  one  (see 
Fig.  584). 

The  positive   ( -i- )  wire  is  connected  to  one 


517 


attachment  screw  of  the  rheostat,  and  to  the 
other  screw  the  wire  conveying  the  current  to 
the  patient.  The  negative  (— )  wire  is  attached 
to  the  electrode  that  is  to  be  held  by  the  patient 
to  complete  the  circuit. 

3Iilliampere-meter. — No  one  should  attempt 
electric  treatment  without  a  milliampere-meter, 
by  which  can  be  seen  exactly 
what  current  strength  is  being 
applied.  The  mterest  in  the  work 
centres  a  great  deal  in  noting  the 
variations  of  current  in  different 
operations. 

To  attach  the  milliampere-meter 
connect  the  +  of  the  battery  to 
the  rheostat,  thence  to  the  m.a. 
meter  and  to  the  patient  (see 
Fig.  585). 

Current-Beverser. — Tlie  battery, 
to  be  complete,  should  have  a 
current-rev^erser,  so  that  the  poles 
may  be  changed  at  will.  Tliis 
contrivance  is  found  on  most 
batteries  on  the  market. 

Current  from  Dynamos. — A  con- 
tinuous current  from  the  main 
(that  is  from  dynamos)  for 
ordinary  lighting  purposes  may  be  used  with 
perfect  safety  and  comfort,  provided  the 
resistance  of  the  switchboard  is  great  enough 
to  reduce  the  current  strength  to  about  one  volt, 
and  can  be  switched  on  to  register  from  a  frac- 
tion of  a  milliampere  with  the  resistance  of  the 
patient's    body    in    circuit.     Switchboards    for 


ejector  should  not  be  used.  With  these  few 
precautions,  which  are,  some  of  them,  doubtful 
sources  of  danger,  and  with  the  current  passing 
through  a  properly  constructed  switchboard, 
the  street  current  may  be  used  with  perfect 
safety. 

If  the  current  is  an  alternating  current,  it 


Fig.  584. — Graphite  Rheostat.     {Schall.) 

thLs  jjurpose  are  supplied  by  instrument-makers, 
and  are  admirably  adapted  to  dental  work. 

A  few  ordinary  precautions  are  necessary  in 
using  current  from  the  main. 

The  chair  should  be  insulated  from  earth,  as 
all  dental  chairs  usually  are.  The  patient  should 
not  be  brought  ui  contact  with  gas  or  water 
pipes,  which  are  connected  usually  with  earth; 
running  water  should  be  avoided,  and  the  saliva 


Fig.  585. — Illustration  of  connections. 

must  be  converted  into  a  continuous ;  this  is 
done  by  motor-transformers,  of  which  there  are 
many  kinds  on  the  market. 

Electrodes. — Suitable  electrodes  for  operations 
ui  the  mouth  are  of  cardinal  importance.  In 
selectmg  an  electrode  for  a  particular  operation, 
the  nature  of  the  tissue  must  be  considered  in 
determining  the  size  of  the  electrode,  for  the 
density  of  current  at  tlie  point  of  contact  varies 
according  to  the  area  of  the  electrode  ;  the  smaller 
the  area  the  greater  is  the  density,  and  conse- 
quently the  more  intensely  will  the  current  be 
felt  at  tlie  point  of  contact.  For  example,  if 
an  electrode  of  the  diameter  of  a  pulp-canal  in- 
strument is  placed  in  a  cavity  of  a  tooth  with 
sensitive  dentine,  and  -5  m.a.  of  cuiTent  is 
applied,  the  patient  will  be  more  likely  to  feel 
pain  than  if  the  same  amount  of  current  is 
passed  with  an  electrode  of  a  diameter  of  one 
millimetre,  because  in  the  latter  the  current  is 
diffused  over  a  larger  area,  and  the  density  is 
thereby  lessened. 

Forms  of  Electrodes. — For  root-canals  fine 
platinum  wire  (or  an  ordinary  steel  nerve- 
instrument)  is  suitable  ;  for  obtunding  sensitive 
dentine,  or  bleaching,  round  jjlatinum  wire 
about  1  millimetre  in  diameter.  For  treating 
periodontal  membrane  and  gums,  platinum, 
zinc,  or  copper  wire,  about  1  millimetre  in 
diameter,  flattened  at  the  end  for  an  inch, 
tapered,  spear-shaped,  and  bent  to  a  slight 
curve,  makes  a  useful  active  electrode.  They 
should  be  insulated  on  the  shanks,  and  inter- 
changeable   to    suitable    ebony    or    vulcanite 


518 


handles   to   which   the  wire  is  connected    (see 
Fig.  586). 

The  indifferent  electrode  should  be  a  cylinder 
of  metal,  which  should  contain  at  the  free  end 
a  moistened  sponge,  and  should  be  held  by  the 


Fig.  586. — Author's  pattern  Electrode  and  Handle. 

patient.  The  skin  in  the  palm  of  the  hand  has 
a  greater  resistance  than  in  most  parts  of  the 
body,  and  is  less  liable  to  be  affected  by  the 
electrolytic  action  of  a  moistened  electrode 
(see  Fig.  587). 


much  reduced,  and  the  current  strength  is  very 
great.  The  cells  are  connected  in  parallel 
arrangement,  that  is,  all  the  +  plates  are 
connected  and  all  the  —  plates  (see  Fig.  588). 

When  cells  are  connected  in  parallel  the 
E.M.F.  is  the  same  as  one  cell,  but  the  internal 
resistance  (r)  is  reduced  by  as  many  times  as 
there  are  cells  in  the  combination,  in  consequence 
of  the  area  of  the  cross-section  of  the  plates 
being  increased  by  so  much  in  what  is  practi- 
cally one  cell.  If,  say,  4  cells  are  connected  in 
parallel,  and  each  cell  is  2  volts  with  internal 
resistance  (r)  of  1  ohm,  and  external  resistance 
(R)  of  i  ohm,  this  would  amount  to  one  large 
cell  of  2  volts  with  an  internal  resistance  of  one- 
fourth  of  that  of  an  individual  cell ;  worked  out 
according  to  Ohm's  Law  these  cells  would 
yield  a  current  strength  of  2-6  amperes,  thus — 


Fig.  587. — Hand  indifferent  Electrode. 

Testing  the  Poles. — To  determine  the  correct 
poles  of  a  l^attery,  or  current  from  dynamos,  one 
of  the  following  sample  tests  will  suffice  to  dispel 
any  feeling  of  doubt  that  might  enter  the  mind 
of  one  unfamiliar  with  electricity,  and  will  en- 
sure accuracy  and  so  will  inspire 
confidence. 

1.  Put  a  few  drops  of  phenol - 
phthalein  in  a  glass  of  water,  and 
place  two  small  electrodes  a  little 
apart  in  the  water ;  switch  on 
a  few  milliamperes  of  current, 
and  a  bright  purple  colouring  of 
the  water  will  take  place  at  the 
negative  pole.  The  positive  ele- 
ment is  of  acid,  and  the  negative 
of  alkaline,  reaction ;  it  is  the 
alkaline  reaction  on  the  plienol- 
phthalein  that  causes  the  colouring. 

2.  Electrolysis  of  Water. — The  pole  that 
collects  twice  as  much  gas  as  the  other  is  the 
negative  pole ;  the  H„0  is  split  up  into  H.^  ions, 
which  are  attracted"  to  the  negative  element, 
and  O  ions,  A\hich  are  attracted  to  the  positive. 

3.  The  mniiamperemeter  needle  always 
deflects  in  the  same  direction  for  the  same  pole, 
usually  to  the  left  for  the  positive  pole  ;  if  the 
needle  deflects  in  the  direction  opposite  to  the 
known  positive  pole  direction,  then  the  poles 
have  been  changed,  and  simply  reversing  the 
plug  will  correct  the  poles. 

Cautery. — For  cautery  work,  cells  with  low 
internal  resistance  and  high  current  strength 
are  necessary.  For  this  purpose,  Leclanche 
cells  are  of  little  use  on  account  of  the  high 
internal  resistance.  The  chromic  acid  or 
Grove's  cells  are  generally  used ;  the  plates  used 
in  tlieir  construction  being  of  large  area  and 
placed  close  together,  internal  resistance  is  very 


E.M.F. 

R  +  1- 


=  C 


2  volts 


:_  =  2-6  amperes 


But  if  the  same  cells  are  connected  in  series, 
the  E.M.F.  will  be  greater,  but  the  yield  of 
current  will  be  less,  on  account  of  the  internal 
resistance  being  greater,  thus — 


E.M.F. 
R  +  r 


I'l  amperes 


Fig.  588. — Cells  in  parallel. 

The  cell  battery  in  parallel  form  for  cautery 
work  has  been  partly  superseded  by   accumu- 


FiG.  589.— Accumulator.     {Sctiall.) 

lators,   or  secondary   batteries,   which  can   be 
recharged  and  are  very  effective. 


519 


A  4-volt  accumulator  of  45  ampere-hours' 
capacity,  sold  by  most  instrument-makers,  is  a 
useful  form  (see  Fig.  589.) 

A  simple  platinum  loop  burner  is  all  that  is 
required  for  most  dental  operations  (see  Fig. 
590). 

The  cautery  has  its  useful  place  in  dental 
surgery ;  in  orthodontic  work,  the  fraenum  labii 
is  often  found  to  be  the  cause  of  separation  of 
the  central  incisors,  its  attachment  being  well 
between  the  two  teeth  ;  the  most  effective  means 
of  dividing  and  eradicating  this  ligament  is  by 
the  cautery.  The  operation  can  be  painlessly 
done  by  anaesthetizing  the  tissue  previously. 
Many  other  minor  operations  m  the  mouth  find 
a  use  for  the  cautery. 

CATAPHORESIS 

Li  electro-therapeutics  as  applied  to  medical 
treatment  the  current  is  used  principally  m  the 
form  of  faradic,  static,  and  galvanic  electricity, 
and  the  effects  sought  are  chiefly  stimulating, 
sedative,  ionic,  and  trophic;  in  dental  electro- 
therapeutics galvanic  electricity  is  used  prm- 
cipally,  and  the  effects  sought 
are  electro -osmosis,  electro - 
diffusion  or  cataphoresis,  and 
ionic  medication.  These  are 
physico  -  chemical  effects  pro- 
duced by  the  current.  Cata- 
phoresis may  be  defined  as 
the  property  possessed  by 
electric  current  of  transporting  non-dissociated 
molecules  of  liquid  en  masse  through  a  tissue 
in  the  direction  of  flow  of  the  current.  The 
direction  of  transport  is  from  the  positive  to 
the  negative  pole  ;  certain  substances  have  been 
described  as  passing  from  negative  to  positive, 
e.  g.  iodine,  peroxide  of  hydrogen,  chlorine, 
etc.,  but  those  substances  correspond  with 
those  which  in  ionization  are  termed  electro- 
negative ;  the  effects  obtained  by  the  use  of 
the  negative  pole  are  altogether  due  to  the 
transporting  of  ions,  and  not  to  cataphoresis. 
The  cataphoretic  effect  is  one  of  pressure  in 
the  direction  of  current — the  passing  of  mole- 
cules from  the  greater  to  the  lesser  potential, 
by  which  "  liquids  and  whatever  they  may 
contain  in  solution  "  (9,  p.  77)  are  transported 
en  masse. 

Little  attention  is  paid  to  cataphoresis  in 
medical  electricity,  principally  because  the  skin 
is  difficult  to  penetrate,  and  the  effect  is  not 
far-reaching  enough  to  medicate  deep-seated 
tissues,  on  account  of  the  absorption  that  takes 
place  in  transit ;  but  in  treatment  of  mucous  and 
periodontal  membrane  of  the  mouth  the  penetra- 
tion is  rapid  and  the  effect  far-reaching  enough, 
if  sufficient  current  can  be  passed  without 
producing   pain. 


Many  interesting  experiments  have  been 
performed  by  Morton  (9,  p.  91),  Gautier  (2), 
Edison,  Bacquerel,  and  others  to  show  the 
physical  and  physiological  effects  of  cataphor- 
esis. Dawson  Turner  (11,  p.  294)  refers  to  the 
treatment  of  cases  of  gouty  concretions  with 
solution  of  lithium  chloride  by  cataphoresis,  in 
which  lithium  urate  was  detected  in  the  urine. 
It  has  been  applied  in  dental  practice  for 
obtunding  sensitive  dentine  for  over  twenty 
years,  and  the  author  has  used  it  for  many  years 
"for  treating  pyorrhoea  alveolaris.  Amongst  the 
early  workers  in  cataphoresis  for  obtunding 
dentine  were  D.  F.  McGraw  of  California  (8), 
A.  C.  Westlake  of  Elizabeth,  New  Jersey  (12), 
W.  H.  Gillett  of  Newport,  Rhode  Island  (3), 
W.  J.  Morton  of  New  York  (9,  p.  197)  and  many 
others. 

IONIC    MEDICATION 

Whilst  taking  into  account  the  osmotic  effect 
of  the  current,  the  more  important  electrolytic 
effect  must  not  be  overlooked.  The  body  must 
be  regarded  as  an  electrolyte  of  homogenous 
nature,  in  which  certain  chemical  changes  take 


Fig.  590. — Cautery  loops.     (Schall.) 

place  when  an  electric  current  is  passed  through 
it,  in  the  same  way  as  chemical  changes  take 
place  in  a  voltaic  cell. 

When  a  current  is  passed  through  a  conduct- 
ing liquid  or  electrol}d;e,  it  has  the  property  of 
splitting  up  the  molecules  into  atoms  of  the 
chemical  component  parts,  which  are  charged 
with  electricity  and  become  dissociated,  certain 
kinds  being  attracted  by  the  +  pole,  and  others 
going  to  the  —  pole ;  these  atoms  constitute  the 
ions  m  electrolysis. 

If  an  electrode  of  gold  is  connected  to  the 
positive  pole  of  a  battery,  and  another  of  German 
silver  to  the  negative  pole,  and  the  current  is 
passed  through  a  solution  of  cyanide  of  gold  as 
the  electrolyte,  the  molecules  of  cyanide  of  gold 
in  solution  are  split  up  into  the  chemical  com- 
ponent parts.  Ions  of  gold  are  attracted  to  the 
German  silver  electrode  at  the  —  pole,  where 
they  give  up  their  charge  of  electricity,  and 
pure  gold  is  deposited  on  the  kathode,  "  plating 
it  with  gold  "  ;  whilst  cyanogen  ions  are  attracted 
to  the  +  pole,  where  it  attacks  the  gold  anode 
in  consequence  of  its  chemical  affinity  for  the 
metal,  uniting  chemically  with  it  once  more  to 
form  molecules  of  gold  cyanide  in  solution. 
Electrolysis  of  water  also  takes  place  at  the 
same  time.  Ho  ions  forming  at  the  —  electrode 


520 


and  O  ions  collecting  at  the  +  electrode.  This  is 
the  process  that  takes  place  when  a  metal 
electrode  is  placed  in  contact  wdth  a  tissue,  with  a 
liquid  electrolyte  as  conductor  of  the  current. 

Certain  ions  are  repelled  from  the  anode  (+), 
while  others  are  repelled  from  the  kathode  (— ). 
A  knowledge  of  the  direction  of  the  ions  obtain- 
able from  a  compound  in  solution  is  necessary 
for  ionic  medication.  The  investigations  of 
many  recent  workers  m  medical  electricity 
have  furnished  a  list  of  these,  which  serve  the 
purposes  of  dental  \\ork. 

Under  the  head  of  Electro-positive,  that  is, 
ions  that  migrate  from  the  +  to  the  —  pole, 
are  the  following  :  hydrogen,  zinc,  copper,  silver, 
gold,  iron,  mercury,  potassium,  sodium,  and 
magnesium.  Under  the  head  of  Electro-nega- 
tive, that  Ls,  ions  that  migrate  from  the  —  to 
the  +  pole,  are  the  following  :  oxygen,  chlorine, 
sulphur,  nitrogen,  bromide,  iodine,  arsenic, 
phosphorus,  and  fluorine. 

Salts  of  certain  oxidizable  metals,  brought 
m  contact  with  moist  tissue  with  an  electric 
current  become  dissolved  by  chemical  reaction 
of  the  metallic  salts  with  the  chlorine  or  oxy- 
gen constituents  of  the  tissue,  and  liberate 
free  ions  which  penetrate  the  tissue ;  of  these 
zinc  and  copper  are  the  most  useful  for  ionic 
medication  in  dental  treatment. 

The  theory  and  practice  of  ionization  has  been 
brought  up  to  date  by  Lewis  Jones,  in  a  paper 
read  before  the  Royal  Society  of  Medicine, 
February  28,  1908,  in  a  very  ex'plicit  and  most 
instructive  manner,  and  much  information  on 
the  subject  is  also  to  be  found  in  his  book, 
Medical  Electricity.  Dawson  Turner  explains 
the  origm  and  action  of  ions  in  his  book.  Manual 
of  Practical  Electricity;  and  useful  hiformation 
is  to  be  found  on  the  theory  of  ions  ui  Guille- 
minot's  book.  Electricity  in  Medicine. 

W.  J.  Morton  ascribes  electric  medication 
solely  to  the  cataphoretic  effect,  but  in  the  case 
of  anaphoresis,  where  the  direction  of  the  flow 
of  current  is  reversed,  ionization  is  probably 
the  only  effect,  whilst  in  cataphoresis  both 
electro-osmosis  and  ionic  medication  may  go  on 
at  the  same  time.  A  convincmg  experiment  to 
show  the  cataphoretic  and  ionic  effect  of  the 
current  consists  m  placing  two  small  copper 
electrodes  one  inch  apart  into  the  white  of  a 
hard-boiled  egg  and  turning  on  3  or  4  m.a.  of 
current ;  the  albumen  at  the  +  pole  will  be 
immediately  stained  a  bright  green,  which  will 
extend  in  every  direction  but  chiefly  towards 
the  position  of  the  —  pole ;  at  the  same  time  at 
the  —  pole  drops  of  liquid  will  accumulate. 
The  green  stain  is  composed  partly  of  chloride  of 
copper,  formed  by  chemical  union  of  the  solu- 
ble electrode  witli  chlorine  in  the  albumen,  and 
partly  of  ions  of  copper  migrated  in  the  direc- 
tion of  the  attracting  negative  pole ;  this  pro-  ■ 


cess  illustrates  ionic  medication.  The  drops  of 
water  formed  at  the  —  pole  consists  of  liquid 
driven  en  masse  towards  the  pole  of  lower  poten- 
tial, and  the  process  illustrates  cataphoresis. 

TREATMENT 

Obtunding  of  Dentine. — To  obtund  sensitive 
dentine,  first  apply  the  rubber-dam,  dry  the  tooth 
and  cavity,  and  place  in  the  cavity  a  pellet  of 
cotton-wool  saturated  with  a  20'!ii  solution  of 
codraline,  novocaine,  or  cocaine  that  has  been 
slightly  warmed,  allowing  no  excess  of  the  solu- 
tion to  leak  out  at  the  neck  of  the  tooth ;  apply 
to  the  cavity  a  suitable  platinum  electrode  con- 
nected with  the  +  pole  and  direct  the  patient  to 
hold  the  —  electrode ;  press  the  electrode  firmly 
into  the  cotton-wool,  without  allowing  the 
metal  to  come  into  actual  contact  with  the 
dentine ;  turn  on  the  current  slowly  through  a 
finely  graduated  rheostat  until  a  slight  sensation 
is  indicated  by  the  patient,  when  only  a  fraction 
of  a  m.a.  of  current  may  be  registered  by  the 
m.a.  meter.  After  a  minute  or  two  at  this 
stage  the  current  may  be  further  increased  mitil 
it  is  felt ;  in  this  way  gradually  mcrease  the 
current,  untU  from  -5  to  3  m.a.  are  registered, 
a  process  that  may  take  from  5  to  10  minutes, 
according  to  the  density  of  the  dentine  or  the 
thickness  of  the  layer  over  the  pulp.  Current 
strength  in  milliamperes  necessary  to  induce 
anaesthesia  in  dentine  varies  greatly ;  it  may  be 
only  -5  m.a.,  or  as  much  as  4  m.a.  In  large 
cavities,  a  good  plan  is  to  place  a  pellet  of 
platuium  foil  over  the  cotton-wool  containing 
the  anaesthetic,  and  press  it  firmly  into  the 
cavity  with  the  metal  electrode ;  the  object  of 
this  is  to  lessen  the  density  of  the  current,  for 
the  greater  the  area  of  the  electrode  the  less 
concentrated  is  the  current,  and  consequently 
the  less  painful.  In  obtunding  dentme  by  electri- 
city the  pulp  is  often  anaesthetized,  and  care 
should  be  taken  in  preparmg  the  cavity  not  to 
expose  it.  The  current  must  be  reduced  to 
zero  by  reversing  the  rheostat  before  removing 
the  electrode  from  the  cavity,  in  order  to  prevent 
the  paiirful  shock  that  would  occur  by  suddenly 
breaking  the  contact. 

Pulp  Anaesthesia. — Clean.se  the  cavity  of 
superficial  debris  and  dry  it ;  apply  the  anaes- 
thetic in  the  same  manner  as  for  obtunding 
dentine.  If  the  cavity  approaches  the  im- 
mediate vicinity  of  the  pulp,  the  apfilication 
should  be  continued  until  3  or  4  m.a.  are  regis- 
tered, which  will  be  sufficient  evidence  that 
anaesthesia  is  complete ;  if  the  layer  of  dentine 
over  the  pulp  is  of  considerable  thickness,  a 
portion  of  it  should  be  removed  after  5  or  6 
minutes'  application,  and  another  application 
made  to  complete  the  operation ;  if  the  pulp  is 
actually  exposed,  very  gradual  application  of 


521 


current  of  low  E.M.F.  should  be  used  at  first ; 
it  should  be  slowly  increased  after  2  or  3 
minutes,  without  producing  pain,  until  3  or 
4  ni.a.  are  registered,  which  will  be  sufficient 
proof  that  tlie  pulp  is  anaesthetized.  The 
current  must  be  reduced  to  zero  before  removing 
the  electrode  in  all  treatment  of  live  teeth. 

Electro-sterilization  of  Root-Canals. — A  perfect 
method  of  sterilizing  root-canals  is  to  be  found 
in  ionic  medication.  In  a  tortuous  or  con- 
stricted canal,  the  application  of  2  or  3  m.a. 
of  current  for  5  or  6  minutes  is  sufficient 
to  produce  ions  from  a  compound  solution  of 
antiseptic  salts,  which  will  penetrate  the  length 
of  the  canal  and  sterilize  it  effectively.  The 
saturation  of  the  tubules  with  septic  matter  in 
long-standmg  purulent  canals  often  makes 
ordinary  antiseptic  dressings  too  superficial 
and  imperfect  to  accomplish  complete  steriliza- 
tion ;  but  by  ionic  medication  with  some 
powerful  antiseptic  salt,  such  as  zinc  chloride 
or  silver  nitrate,  the  tubules  are  penetrated  by 
zinc  or  silver  ions,  and  perfect  sterilization  of 
the  lining  walls  of  the  canals  is  effected.  In 
treatmg  root-canals,  the  rubber-dam  should  be 
applied  when  there  is  any  chance  of  moisture 
from  the  mouth  interfering ;  and  the  canals 
should  be  cleared  of  all  available  fragments 
of  diseased  tissue  without  using  reamers  or 
drUls.  A  fine  root-canal  instrument,  wrapped 
with  a  little  cotton-wool  saturated  with  the 
antiseptic  solution  should  be  passed  into  the 
canal  to  the  apex,  or  as  far  towards  it  as  space 
will  permit ;  and  the  current  should  be  applied 
by  comiecting  the  +  electrode  to  the  instrument 
in  the  canal,  and  switching  on  the  current 
gradually  until  2  to  4  m.a.  are  indicated  by  the 
m.a.  meter.  Five  or  six  minutes  will  be  suffi- 
cient to  sterilize  the  canal,  and  two  or  three 
canals  m  one  tooth  can  be  done  at  the  same 
time  by  placing  electrodes  in  each  and  connect- 
ing them  all  m  ith  the  current  electrode.  A  5% 
solution  of  zinc  chloride  for  anterior  teeth,  or 
a  solution  of  silver  nitrate  for  posterior  teeth, 
are  effective  drugs  for  this  treatment. 

Some  autliors  have  advocated  the  use  of  the 
current  in  electro-sterilization  without  antisep- 
tics, claiming  that  it  is  sufficient  in  itself  to 
sterilize  root -canals  ;  but  as  normal  salt  solution 
is  generally  used  by  them  as  the  solution 
electrode,  it  is  possible  that  sodium  ions  formed 
by  the  electrolytic  effect  are  resjjonsible  for 
the  results  obtained. 

Josef  Peter,  of  Vienna  (10),  in  advocating 
electric  current  for  sterilizing  roots,  states  that 
"  solution  of  common  salt  is  a  suitable  elec- 
trolyte ".  Zierler  and  Letemann  (13),  experi- 
menting with  the  current  on  agar-cultures  of 
anthrax  bacilli,  micrococcus  pyogenes  aiireus 
and  albus,  and  bacillus  coli,  found  that  "  two 
mUliamperes  acting  for  10  minutes  created  at 
17* 


the  anode  a  sterile  region  from  1  to  r5  cm.  in 
diameter ".  There  is,  however,  no  objection 
to  usmg  antiseptic  salts  in  solution  as  the 
solution  electrode,  and  the  results  are  likely 
to  be  more  certain  by  the  addition  of  ions 
obtainable  from  them. 

Lewis  Jones  (5)  refers  to  root  sterUization  as 
advocated  by  E.  Zierler,  who  used  the  negative 
electrode  applied  to  the  gum,  in  the  vicinity  of 
the  tooth  containing  the  positive  electrode ; 
this  technique  is  likely  to  be  more  painful  and 
not  more  effective  than  directing  the  patient  to 
hold  the  negative  electrode  in  the  hand. 

Acute  Periodontitis. — In  septic  mfection  at  the 
apex  of  the  root  threatening  alveolar  abscess,  a 
single  application  of  zinc  ions,  in  the  same 
manner  as  for  sterilizing  roots,  wUl  sometimes 
terminate  the  disturbance  and  give  rapid  relief  ; 
a  5%  solution  of  zinc  cliloride  with  2  to  4  m.a. 
of  current  should  be  applied  for  10  minutes, 
and  from  this  ions  of  zinc  are  driven  through 
the  foramen  at  the  apex  into  the  affected  perio- 
dontal membrane.  A  more  effective  antiseptic, 
and  at  the  same  time  one  more  easily  tolerated 
by  the  tissues,  would  be  hard  to  find. 

Chronic    Alveolar    Abscess. — Chronic    alveolar 
abscess    with    fistulous    opening    on  the   gums 
should  be  first  treated  in  the  same  manner  with 
zinc  ions  passed  into  the  canals.     In  addition, 
afterwards,  pass  a  fine  copper  probe  along  the 
'  fistulous  tract  to  its  origm  at  the  apes  of  the 
I  root ;  leave  it  in  position,  and  connect  the  -f 
electrode  to  it,  and  very  gradually  turn  on  the 
current  until  from  1  to  4  m.a.  are  recorded  (or 
less,  if  painful),  for  five  minutes.     The  soluble 
copper  electrode  will  be  dissolved  by  the  electro- 
lytic action,  and  free  ions  of  copper  will  pass 
into  the  tissue,  effectively  sterilizing  the  infected 
tract ;  two  or  three  such  treatments  will  often 
permanently    cure     a     long-standing     chronic 
abscess.     Should  the  copper   probe   adhere   to 
the  tissues,  it  can  be  released  by  reversing  the 
poles  and  applying  the  —  current  for  a  minute. 
Treatment  of  Pyorrhoea  Alveolaris. — Of  the  many 
important  uses    to    which    electro-theraijeutics 
lends  itself  in  dental  practice,  probably  the  most 
important  is  the  treatment  of  chronic  suppura- 
tive affections  of  the  gums,  periodontal  mem- 
brane, and  alveolus,  in  which  these  tissues  are 
involved  in  a  form  of  septic  infection  that  is 
difficult  to  deal  with  in  the  ordinary  way.     In  the 
early  stages  of  pyorrhoea  alveolaris  ionic  medi- 
cation is  most  effective  in  curing  the  disease,  and 
even  in  the  worst  stages,  the  pus  can  be  checked 
and  the  tissues  rendered  healthy.    Constitutional 
disorders  of  more  or  less  grave  character  often 
accompany  pyorrhoea  alveolaris,  due  to  absorp- 
tion  mto   the   system   of   micro-organisms ;    ui 
these  cases,  if  the  system  is  rendered  immune 
to  the  organism  or  organisms  predominating  in 
the  uifection  by  vaccine  therapy  (as  described 


522 


ia  Chapter  XXX),  and  if  at  the  same  time 
local  treatment  is  vigorously  kept  up  by  ionic 
medication,  the  disease  will  yield  to  treatment. 

The  technique  of  electrical  treatment  here  is 
as  follows  :  A  limited  number  of  teeth,  say  six 
upper  or  lower  incisors,  are  dried,  and  the  saliva 
is  kept  away  by  cotton-wool  rolls  or  napkms ; 
the  patient  should  hold  the  negative  electrode 
in  the  hand,  and  a  suitable  positive  electrode 
should  be  w  rapped  with  a  few  threads  of  cotton- 
wool moistened  with  the  antiseptic  drug ;  this 
should  be  introduced  mto  the  pockets  and  spaces 
between  the  teeth,  and  the  current  switched  on 
gradually  until  the  patient  indicates  that  it  is 
bemg  felt.  According  to  the  sensitiveness  of 
the  teeth  and  tissues,  the  current  strength 
necessary  will  vary  between  1  and  4  milliam- 
peres ;  the  former  strength  is  sufficient  to 
liberate  ions,  although  it  is  desirable  to  iise  a 
stronger  current  if  possible.  The  electrode 
should  be  slowly  passed  around  the  necks  of 
the  teeth  and  mto  the  depth  of  the  pockets,  and 
kept  in  constant  contact  with  the  tissues,  except 
when  it  is  necessary  to  replenish  the  liquid. 
The  time  required  to  sterilize  the  tissues  varies 
according  to  the  severity  of  the  disease ;  ions 
of  salts  are  formed  uistantaneously,  and  the 
amount  of  sterilization  required  must  be  de- 
termmed  by  the  operator.  Where  the  disease 
is  deep-seated  and  the  discharge  considerable, 
the  electrode  should  be  kept  in  contact  at  that 
particular  part  for  one  to  three  minutes,  accord- 
ing to  the  amount  of  penetration  of  ions  it  is 
deemed  necessary  to  procure.  A  good  plan  is 
to  keep  the  electrode  in  a  pocket  to  be  treated 
until  this  is  tlio roughly  sterihzed,  reduce  the 
current  to  zero,  and  move  the  electrode  to  the 
next  position  before  turning  on  the  current 
again.  It  must  be  distmctly  understood  that 
no  amount  of  treatment  will  do  any  lasting 
good  if  the  calcareous  deposits  are  not  com- 
pletely removed ;  it  should  be  the  aim  of  the 
operator  to  remove  every  particle  of  deposit,  a 
process  that  may  take  a  portion  of  the  time  at 
every  sitting  during  a  long  course  of  treatment, 
and  still  be  imperfect.  The  surfaces  of  the  teeth 
should  also  be  polished. 

For  the  first  treatment,  ^^'hen  the  tissues  are 
more  or  less  lacerated  from  extensive  scaling 
operations,  a  soothing  drug,  such  as  argyrol, 
5%  aqueous  solution,  should  be  used.  A  period 
of  thirty  to  forty-five  mmutes  of  this  treatment 
is  as  much  as  most  patients  will  endure,  even  it 
not  painful ;  the  operation  should  be  repeated 
on  the  third  day,  when  5%  aqueous  solution  of 
zinc  chloride  should  be  used,  from  which  ions 
of  zmc  are  obtained ;  this  is  probably  the  mo.st 
effective  antiseptic,  and  at  the  same  time  the 
one  best  tolerated  by  the  tissues.  Of  zinc  ions 
S.  Leduc  (6)  says :  "  This  ion  is  an  antiseptic  of 
the  first  rank,  and  when  applied  electrically,  it 
can  be  made  to  penetrate  the  tissues  of  the  skin 


to  any  desired  depth.  There  is  no  wound  or 
ulcer  which  cannot  be  disinfected  by  its  em- 
ployment, provided  its  surface  can  be  reached 
by  the  electrodes.  One  of  its  peculiarities  is  that 
it  provokes  but  little  inflammatory  reaction. 
When  I  have  experimented  with  zinc  upon  the 
skin  of  animals,  and  have  caused  superficial  or 
even  deep  idceration,  I  have  observed  that  the 
wounds  produced  show  no  inflammatory  effects 
or  signs  of  mfection  from  germs,  even  if  they 
are  left  completely  uncovered ;  on  the  contrary 
they  remain  aseptic,  so  that  it  appears  as  if  the 
ions  of  zinc  which  they  contam  serve  as  the 
best  possible  of  antiseptic  agents." 

The  writer's  experience  with  the  use  of  zinc 
ions  m  the  treatment  of  pyorrhoea  is  tliat  there 
is  no  other  antiseptic  that  wiU  stop  the  discharge 
of  pus  so  effectively  or  so  quickly.  Three 
treatments  the  first  week,  two  the  second  and 
third  weeks,  and  one  every  five  or  six  days 
subsequently,  until  the  tissues  have  resumed  a 
perfectly  healthy  appearance,  form  a  sequence 
that  is  as  near  as  possible  to  any  rule  that  can 
be  laid  down  for  the  intervals  of  treatments. 
The  operator  should  be  guided  by  his  judgement 
in  each  mdividual  case,  two  or  three  treatments 
being  all  that  wiU  sometimes  be  necessary  when 
only  one  or  two  teeth  are  affected. 

In  cases  of  wasting  of  the  gums  on  the  labial 
and  buccal  aspects  of  the  teeth  where  no  dis- 
charge of  pus  is  visible,  ionization  obtained  by 
passing  the  electrode  under  the  thin  margin  of 
gum  and  using  a  5%  solution  of  zmc  chloride 
as  the  electrolyte  will  effectively  stop  reces- 
sion and  relieve  the  sensitiveness  of  the  necks 
of  the  teeth  that  nearly  always  accompanies 
this  form  of  pyorrhoea.  A  low  current 
strength,  '5  to  1  m.a.,  will  often  be  all  that  can 
be  endured  at  first ;  but  gradually  the  use  of 
more  wUl  be  possible,  and  the  effect  is  lastmg, 
for  after  a  year  or  two  the  teeth  will  often  be 
found  to  have  lost  all  sensitiveness,  and  it  will 
then  be  possible  to  apply  2  or  3  m.a.  if  further 
treatment  is  necessary. 

Other  drugs  that  can  be  used  with  good 
effect  in  the  treatment  of  pyorrhoea  are  tincture 
of  iodine  (diluted  with  equal  parts  of  water), 
caprol,  and  copper  sulphate.  In  using  iodine 
the  negative  electrode  must  be  applied  to  the 
tissues,  as  iodine  ions  are  liberated  at  the  — 
pole.  Caprol,  from  which  ions  of  copper  are 
obtamed  by  the  current,  is  a  powerful  antisep- 
tic salt ;  it  should  be  used  in  5%  aqueous  solu- 
tion, to  which  should  be  added  five  per  cent 
of  chloretone.  Copper  sulphate,  from  which 
copper  ions  are  obtained,  may  be  used  in  very 
dilute  aqueous  solution  (1  in  500). 

The  whole  principle  of  electro-therapeutic 
treatment  of  suppurative  affections  of  the 
gums  and  periodontal  membrane  is  based  on 
the  penetration  of  ions  procurable  by  the 
electrolytic  effect  of  the  current  on  compounds 


523 


of  antiseptic  salts,  by  which  the  micro-organisms 
contained  in  the  tissues  are  effectively  destroyed, 
and  the  tissues  stimulated  to  repair.  Further- 
more, the  dead  bacteria  are  probably  absorbed 
into  the  general  circulation,  and  have  an  effect 
on  the  opsonins. 

Bleaching  by  Electric  Current. — To  bleach 
discoloured  teeth  with  the  aid  of  the  electric 
current,  due  consideration  must  be  given,  as 
in  ordinary  bleaching,  to  the  cause  of  tlie 
discoloration  and  the  nature  of  the  stain. 
If  the  colouring  matter  responsible  for  tlie 
dLscoloration  is  of  purely  organic  origin,  the 
possibility  of  bleaching  by  this  method  is  a 
valuable  aid  in  this  difficult  problem ;  if, 
however,  it  is  inorganic,  the  difficulty  of  trans- 
formmg  such  matter  into  translucent  substance 
is  very  much  increased.  Where  organic  stams 
are  concerned,  bleaching  can  readily  be  effected 
by  using  25%  ethereal  solution  of  hydrogen 
peroxide  made  into  an  aqueous  solution  by 
adding  half  the  volume  of  water,  with  a  small 
quantity  of  sodium  sulphate,  and  then  dispelling 
the  ether  of  the  liydrogen  peroxide  by  evapor- 
ating over  a  warm  water  bath.  The  hydrogen 
peroxide  is  practically  a  non-conductor  of 
current  in  tlie  pure  state  ;  the  addition  of  water 
and  sodium  sulphate  makes  it  highly  conductive. 
A  tooth  to  be  bleached  requires  special  prepara- 
tion :  the  rubber-dam  should  be  applied,  and 
the  root-canal  cleansed,  and  filled  at  the  apex 
only  with  gutta-percha ;  the  bleaching  liquid, 
which  is  the  solution  electrode,  should  penetrate 
the  length  of  the  root-canal  to  the  filling  of  gutta- 
percha, because  a  dead  tooth  offers  great  resist- 
ance to  current.  (Six  to  ten  volts  applied  m  a 
cavity  of  a  dead  tooth  will  only  admit  of  perhaps 
one  milliampere  of  current  strength,  but  if  the 
current  is  conducted  well  into  the  root  the 
resistance  is  lessened  and  a  greater  current 
strength  obtained  with  less  volts.)  The  peroxide 
of  hydrogen  should  be  applied  on  cotton-wool 
passed  weO  into  the  canals,  and  a  platinum 
electrode  used  in  the  same  mamier  as  for 
obtunding.  Care  should  be  exercised  that  the 
electrode  is  not  brought  into  contact  with  soft 
tissues,  because  of  tlie  high  voltage  required  to 
overcome  the  increased  resistance.  The  positive 
pole  is  applied,  and  the  liquid  bleaching  solution 
is  driven  towards  the  pole  of  lower  potential. 
The  wTiter  has  observed  that  ionization  with 
hydrogen  peroxide  is  sometimes  more  effective 
than  cataphoresis  :  the  ions  are  repelled  from  the 
negative  pole  and  seem  to  have  a  more  penetrat- 
ing effect  on  the  dentine.  Hence  it  has  been 
stated  that  when  bleaching  will  not  succeed 
with  the  positive  electrode,  by  reversing  the 
poles  and  applying  the  negative  electrode  the 
desired  effect  can  be  brought  about  in  a 
remarkable  manner. 

The  current  is  also  a  valuable  aid  in  bleach- 
ing   with    calcium    hypochlorite    ("  bleaching 


powder  "),  from  which  chlorine  is  liberated 
to  act  chemically  on  the  discoloured  matter  in 
the  tubules.  The  value  of  the  current  in  this 
respect  seems  to  depend  on  the  electrolytic 
effect  on  the  water  in  the  dilute  acetic  acid. 
Chlorine  has  a  great  affinity  for  hydrogen,  and 
\\iLl  unite  with  tlie  H._,  molecule  of  water,  hbera- 
ting  0  under  ordinary  circumstances.  When 
electrolysis  is  employed  in  a  mixture  m  which 
chlorine  is  being  set  free,  the  H.,  molecules 
combme  with  the  chlorme  to  form  hydrochloric 
acid ;  oxygen  m  its  nascent  form  is  liberated, 
and  has  great  affinity  for  organic  matter,  uniting 
^\■ith  it  to  change  it  uito  a  translucent  substance. 

Continuous  Current  and  Ionization  for  Neu- 
ralgia.— Galvanic  current  has  been  advocated 
by  many  authors  for  treatment  of  trigeminal 
neuralgia.  The  difficulty  in  diagnosmg  whether 
the  pain  is  of  reflex  origin,  or  arises  from  some 
affection  of  the  semilunar  ganglion  or  the  nerves 
connected  with  it,  makes  tlie  treatment  of  facial 
neuralgia  by  the  current  of  uncertain  prognosis. 
Drastic  measures  are  often  resorted  to,  by  the 
extraction  of  numerous  sound  teeth,  in  the  hope 
(often  a  vain  one)  of  relieving  persistent  chronic 
facial  neuralgia.  Tliis  is  the  class  of  case  that 
calls  for  electric  treatment.  The  technique 
consists  ui  placing  a  large  active  electrode  over 
the  whole  surface  of  the  affected  side  of  the 
face,  whilst  another  indifferent  electrode  is 
placed  on  the  neck,  and  a  contmuous  current 
of  30  to  80  milliamperes  apf)lied  for  a  dura- 
tion of  30  to  45  minutes.  Tliis  treatment 
should  be  repeated  daily  until  the  pain  dis- 
appears. Guilleminot  (4,  p.  34(3)  says :  "In 
most  cases .  the  treatment  par  excellence  for 
neuralgia  is  that  by  the  galvanic  current." 

Ionic  medication  \\ith  sodium  salicylate,  and 
also  bichloride  of  quinine,  in  severe  cases  of  tic 
douloureux  has  been  advocated  by  Leduc  of 
Nantes  (7),  who  details  remarkable  cures  of  very 
severe  cases  of  this  painful  disease  by  salicylic 
ions  and  quinine  ions. 

E.  S. 

BIBLIOGRAPHY 

(1)  Archives  D'ELECTRiciTiMEDiCALE.  July  25, 1904. 

(2)  Gautier.      Technique  d'Electrotherapie,  VI.  p.  m. 

(3)  GiLLETT,    W.     H.      Cataphoresis    for    Obtunding 

Sensitive  Dentine.     Dental  Cosmos,  1896.     Vol. 
XXXVIIl,  p.  132. 

(4)  Guilleminot.     Electricity  in  Medicine. 

(5)  Jones,  Lewis.     Medical  Electricity,  p.  463. 

(6)  Ledtjc,  S.     Arch.  d'Electricile  me'dicale,  Sept.  25, 

1904.     Les  ions  de  medecine. 

(7)  Leduc,  S.      La  Semaine  M,'dicale.  Nov.  22,  1905. 

(8)  McGr.\w,  D.  F.      Denta/ Co«mo«,  Feb.  1889.     Vol. 

XXXI. 

(9)  Morton,  W.  J.     Cataphoresis. 

(10)  Peter,    Josek.      Odontologische    Blatter,    Berlin, 

July  1905. 

(11)  Turner,  Dawson.     Practical  Medical  Electricity. 

(12)  Westlake,    a.    C.      Dental    Cosmos,    1892.     Vol. 

XXXIV.  p.  887. 

(13)  ZiBRLER    &    Letemann.     Dental    Cosmos,     1905. 

Vol.  XLVIl.  p.  1136. 


CHAPTER    XXXII 


INJURIES   OF   THE   TEETH  DUE   TO   VIOLENCE 


In  common  \\itli  other  hard  structures  of 
the  body,  teeth  are  liable  to  accidental  injuries, 
the  upjJer  incisors,  owing  to  their  shape  and 
position,  particularly  when  unduly  prominent, 
being  the  chief  sufferers.  It  is  usual  to  classify 
such  injuries  under  three  headings  :  Con- 
cussion, Dislocation,  and  Fracture.  These  again 
may  be  subdivided  in  accordance  with  the 
severity  of  the  injury,  as  evidenced  by  the  age 
of  the  patient,  the  degree  of  dislocation,  the 
position  of  the  fracture,  and  the  extent  of  the 
lesion,  if  any,  inflicted  on  the  soft  structures  of 
the  dental  pulp.  Such  mjuries  occasioned  by 
direct  violence  are  of  frequent  occurrence ;  but 
they  may  also  result  from  indirect  violence, 
as  when  a  blow  or  fall  upon  the  chin  causes  the 
teeth  in  the  mandible  to  be  brought  into  contact 
with  those  of  the  maxiUae  with  great  force,  or 
by  muscular  effort  when  the  teeth  are  subjected 
to  improj)er  or  unexpected  uses. 

CONCUSSION 

By  concussion  is  meant  an  injury  resulting 
from  direct  or  indirect  violence,  but  of  a  degree 
insufficient  to  dislocate  or  fracture  the  tooth. 
Such  accidents  are  exceedingly  common,  but 
even  the  most  trivial  may  result  in  the  subse- 
quent death  of  the  pulp.  Usually  the  injury 
is  followed  by  some  periodontitis — the  tooth 
becomes  tender  and  slightly  loose ;  under 
favourable  circvimstances  the  inflammation  may 
be  arrested  at  this  stage  and  speedily  subside. 
Should  the  inflammation  continue,  the  tooth 
becomes  more  tender  and  elongated ;  the  pulp 
may  become  involved,  as  shown  by  its  extreme 
sensitiveness  to  thermal  changes,  the  mere 
drawing  in  through  the  lips  of  cold  air  starting 
acute  pain,  which  radiates  to  adjacent  teeth  or 
is  referred  to  some  other  area  of  the  nerve 
distribution.  Fmally,  the  pulp  may  die,  and  the 
periodontal  mflaramation  progress  to  the  forma- 
tion of  an  alveolar  abscess. 

Sometimes  the  continuity  of  the  soft  struc- 
tures of  the  pulp  with  those  external  to  the  tooth 
is  severed  at  the  apical  foramen  when  the  injury 
occurs ;  there  may  then  be  a  periodontitis  un- 
complicated with  inflammation  of  the  pulp.  Not 
uncommonly  the  concussion  may  lie  apparently 
so  slight  as  to  produce  no  periodontitis,  and  yet 
be  sufficient  to  destroy  at  once  the  vitality  of  the 


524 


pulp  ;  or  this  organ  may  die  shortly  afterwards 
without  any  manifestations  of  acute  mflamma- 
tion.  Such  a  tooth  may  remain  quiescent  for 
many  years,  and  then  suddenly  become  affected 
with  acute  periodontal  inflammation.  It  nearly 
always  shows  some  discoloration,  rangmg  from 
grey  to  black.  The  discoloration  would  seem 
to  be  greater,  howev^er,  in  those  cases  in  which 
the  pulp  died  as  the  result  of  acute  inflammation, 
than  when  it  has  been  killed  outright  at  the  time 
of  the  injury. 

In  all  cases  of  concussion  it  is  necessary  to 
determine  the  extent  of  the  lesion,  if  any, 
received  by  the  pulp.  Should  it  be  dead  the 
sooner  it  is  removed  the  better.  This  may  be 
ascertamed  by  the  absence  of  response  to  thermal 
tests.  A  hole  having  been  punched  m  a  small 
piece  of  rubber-dam,  the  suspected  tooth  is 
passed  through  it  and  so  isolated  from  its 
neighbours,  when  it  may  be  easily  tested  by 
spraying  a  little  ethyl  chloride  upon  it,  or  by 
placmg  a  small  piece  of  superheated  temporary 
gutta-percha  in  contact  with  it.  Access  to  the 
canal  of  an  incisor  for  the  purpose  of  removal 
of  the  pulp  is  obtained  best  through  the  cin- 
gulum ;  in  the  case  of  a  premolar  or  molar, 
directly  through  the  crown.  Should  perio- 
dontitis be  present,  the  operation  may  be 
rendered  less  painful  by  making  a  small  splint 
from  impression  composition,  and  using  it  to 
steady  the  affected  tooth. 

If  when  employing  thermal  tests  an  undue 
response  is  elicited,  some  hyperaemia  of  the 
pulp  may  be  suspected,  and  an  attempt  should 
be  made  to  allay  it  by  the  application  of  counter- 
irritants  to  the  gum  immediately  over  the 
tooth,  such  as  tmcture  of  aconite,  tincture  of 
iodine,  and  chloroform,  in  equal  parts,  or  a 
capsicum  plaster.  Similar  applications  are  also 
indicated  when  periodontitis  is  present.  Should 
this  treatment  fail,  and  acute  inflammation 
ensue,  the  pulp  should  be  removed  under  an 
anaesthetic. 

DISLOCATION 

Dislocation  of  a  tooth  is  usually  caused  by 
direct  rather  than  indirect  violence.  It  may 
be  partial  or  complete,  and  it  is  not  un- 
commonly accompanied  by  some  fracture  of 
the  alveolar  process ;  or  the  root  of  the  tooth 
itself  may  be  fractured  high  up  in  its  socket. 


525 


In  partial  dislocation  the  displacement  may 
occur  in  any  direction,  but  most  frequently 
it  is  inward  towards  the  tongue,  or  the  tooth 
is  driven  into  its  socket.  Treatment  consists 
in  thorouglily  cleansing  the  parts,  reducing  the 
dislocation,  and  mauitaining  the  tooth  in 
absolute  rest  until  it  has  become  firm  again 
in  its  socket.  An  imjjortant  factor  to  be  taken 
into  consideration  is  the  age  of  the  patient.  A 
very  large  percentage  of  teeth  that  have  suffered 
dislocation  die,  and  should  this  occur  m  the 
case  of  a  young  tooth  not  yet  fully  formed, 
further  growth  is  arrested,  and  the  successful 
filling  of  the  root-canal  is  rendered  difficult  and 
sometimes  impossible.  In  such  circumstances 
it  may  be  wise  to  extract  the  tooth,  and  either 
allow  the  space  to  close  up  by  the  falling  together 
of  the  adjacent  teeth,  or  adopt  some  means  for 
preserving  such  space,  with  a  view  to  providing 
an  artificial  substitute  later  on.  In  coming  to  a 
decision  attention  should  be  paid  to  the  sex  of 
the  patient,  the  crowding  of  the  teeth,  and 
aesthetic   considerations  generally. 

In  this  connection  the  following  case  is  of 
interest.  A  small  boy  aged  six  years  fell  and 
struck  his  mouth  against  the  leg  of  a  table, 
completely  dislocating  his  left  upper  central 
incisor,  which  had  erupted  early.  It  was, 
naturally,  only  partly  formed,  but  it  was  replaced 
and  subsequently  became  quite  firm.  It  re- 
mained, however,  in  its  original  position,  and 
failed  to  erupt  further;  nor  was  there  any 
further  growth  of  the  root,  as  was  proved  when 
the  tooth  was  removed  ten  years  later,  owing 
to  its  unsightly  appearance  due  to  its  shortness 
in  relation  to  its  neighbours. 

Teeth  that  have  been  driven  into  their 
sockets  may  be  brought  into  alignment  by 
suitable  forceps.  In  tlie  case  of  upper  canines, 
premolars,  and  molars,  it  must  be  remembered 
that  these  may  have  perforated  the  floor  of  the 
maxillary  sinus  ;  care,  therefore,  is  needed  when 
grasping  these  teeth  to  prevent  their  slipping 
upwards  into  that  cavity.  Teeth  that  have 
been  dislocated  upwards,  and  allowed  to  remain, 
have  a  tendency  to  come  down  of  themselves 
into  a  more  or  less  natural  position.  Some 
years  ago  the  -wTiter  saw  a  smaU  boy  aged 
eight  and  a  half  j'ears  who  a  month  before  had 
fallen  on  a  stile  and  driven  his  right  central 
incisor  upwards  and  outwards  practically  but 
of  sight.  The  tooth  was  then  quite  firm,  and 
as  he  was  going  away  to  school  the  following 
day  it  was  decided  to  leave  it  until  his  next 
holidays.  Wlien  seen  three  months  later  it 
had  come  down  considerably,  and  was  therefore 
left  alone  for  a  further  period  of  four  months ; 
at  the  end  of  this  time  it  had  taken  up  what 
was  practically  its  normal  position ;  the  tooth, 
however,  was  dead.  A  careful  examination 
should  be  made  in  those  cases  in  which  a  tooth 


has  apparently  been  knocked  out  and  lost,  to 
ascertam  that  the  socket  is  really  empty,  and 
that  the  tooth  has  not  been  merely  driven 
upwards  out  of  sight.  The  wTiter  saw  a  man 
who  four  months  previously  had  been  kicked 
by  a  horse  and  had  had  his  mandible  fractured, 
who  stated  that  his  left  upjjer  lateral  incisor 
and  canine  had  been  knocked  out.  He  came 
to  the  hospital  on  account  of  a  swellmg  m  his 
cheek,  with  a  sinus  openmg  externally  and 
discharging  pus.  Aii  examination  with  a  probe 
revealed  the  jjresence  of  a  tooth,  which  was 
removed  without  difficulty  through  a  small 
incision,  and  jjroved  to  be  the  canine  tooth  that 
the  patient  imagined  he  had  lost. 

Methods  of  Retaining  Partially  Dislocated  Teeth, 
As  already  indicated,  a  tooth  that  has  Ijeen 
partially  dislocated  should  be  brought  into 
correct  alignment,  the  alveolus  if  fractured 
carefully  moulded  around  the  root,  and  measures 
taken  to  secure  perfect  rest  until  repair  of  the 
injured  tissues  has  taken  place.  Thus  the  tooth 
may  be  ligatured 
to  the  adjacent 
firm  teeth  by  wir- 
ing in  the  manner 
shown  in  Fig.  591. 
The  tendency, 
always  present,  for 
the  tooth  to  re- 
al a  i  n   slightly 

elongated  is  in  a  measure  guarded  agamst 
by  using  an  extra  loop  of  wire,  passing  it 
through  the  other  loops,  which  fix  the  tooth 
to  its  neighbours,  bringing  it  downwards,  and 
finally  twisting  it  tightly  at  the  incisal  edge  of 
the  tooth.  Fi'equently  it  is  necessary  to  afford 
greater  support  than  can  be  obtained  by  simply 
ligaturing  the  tooth  to  its  fellows,  particularly 
when  the  force  of  occlusion  of  the  oj)posing  teeth 
is  heavy,  or  when  the  affected  tooth  is  unduly 
prominent ;  in  these  circumstances  it  is  often 
better  to  employ  some  kind  of  metal  splint, 
such  as  that  described  below  (Fig.  592). 

In  ca,ses  of  complete  dislocation  the  same 
consideration  nuist  be  given  to  the  age  of  the 
patient  as  in  tliose  of  partial  dislocation.  Should 
the  accident  occur  at  the  hands  of  the  dentist, 
as  may  occasionally  happen,  the  tooth  should 
be  immediately  re2:)laced,  as  there  are  grounds 
for  believing  that  in  young  patients  the  pulp 
structures,  which  have  been  severed  at  the 
apical  foramen,  occasionally  reunite.  Thus, 
an  upper  left  central  incisor  was  extracted  from 
the  mouth  of  a  boy  aged  eleven  years,  in  order 
to  facilitate  the  thorough  removal  of  a  recurrent 
epuloid  growth ;  after  the  operation  the  tooth 
was  replaced  and  retained  in  position  by  a  splint 
previously  prepared.  Four  months  later  the 
tooth  was  quite  firm  and  of  normal  colour,  and 
it  responded  to  thermal  tests  equally  with  the 


526 


other  incisors.  At  any  rate,  teeth  thus  re- 
planted frequently  undergo  little  or  no  sub- 
sequent discoloration.  This  may  be  due  partly 
to  the  fact  that  the  amount  of  blood  extravasa- 
tion in  tlie  pulp  is  but  slight,  compared  with 
those  cases  in  which  the  death  of  the  pulp  has 
been  gradual  and  has  followed  acute  hyperaemia 
of  that  organ.  Should  the  patient  not  be  seen 
until  some  time  after  the  injury,  the  socket 
should  be  syringed  witli  hot  water  and  rendered 
as  aseptic  as  possible,  after  the  removal  of  all 
clots.  The  pulp  of  the  tooth  should  be  extir- 
pated, and  the  canals  sterilized  and  filled  in 
the  usual  manner,  before  the  tooth  is  replanted. 
This  may  be  done  either  through  the  apical 
foramen  or  through  the  most  accessible  portion 
of  the  cro«n  ;  the  latter  usually  gives  tlie  better 


Fig.  592. 

result.  The  tooth  itself  should  be  carefully 
and  thoroughly  cleansed  by  some  warm  anti- 
septic .solution,  such  as  lysol  two  per  cent,  and 
durmg  the  filling  of  the  canals  held  in  lint 
soaked  in  tlie  same. 

The  chances  of  success  are  undoubtedly 
greater  in  those  cases  in  which  the  tooth  is 
replanted  shortly  after  the  injury,  since  the  peri- 
odontal membrane  adherent  to  the  root  of  the 
tooth  retains  its  vitality  for  some  time,  and  a 
membranous  connection  between  the  tooth  and 
its  socket  is  often  secured.  The  direct  trans- 
plantation of  teeth  from  one  mouth  to  another 
has  not  only  been  advocated  but  successfully 
accomplished.  However,  the  necessity  and  the 
opportunity  for  such  an  operation  can  arise 
but  seldom,  and  its  ethics  are  open  to  question. 
A  replanted  tooth  may  serve  for  many  years, 
but  not  infrequently  its  root  becomes  absorbed, 
this    resulting    in    its    ultimately    being     lost. 


Absorption  occurs  more  frequently  when  the 
replantation  has  been  delayed  for  some  time. 
Examination  of  such  a  tooth  reveals  the  fact 
that  there  has  been  chronic  inflammation  in 
the  socket,  and  that  an  alternating  process  of 
absorption  and  deposition  of  cementum  has 
taken  place ;  and  it  may  well  be  that  some 
replanted  teeth  are  kept  in  place  partly  by  the 
hold  afl^orded  by  the  filling  in  of  these  absorption 
spaces. 

Retention  is  secured  better  by  means  of  a 
specially  constracted  splint  than  by  simple 
ligaturing ;  the  most  efficient  is  made  by 
striking  a  piece  of  German  silver  plate  to  fit 
over  the  replaced  and  the  adjacent  teeth,  and 
cementing  it  in  position  with  one  of  the  osteo- 
plastic cements  (Fig.  592).  An  impression  for 
producing  a  model  of  the  parts  can  be  taken 
readily  if  the  tooth  is  ligatured  temporarily 
into  place.  The  advantage  of  such  a  splint  is 
that  it  relieves  the  "  bite  "  and  secures  absolute 
rest.  Its  disadvantage  is  that  it  is  somewhat 
large,  but  as  a  rule  it 
may  be  dispensed  with 
in  a  week  or  ten  days. 
Another  useful  splint 
is  one  made  of  thin 
German  silver  bands 
soldered  together  and  ^'°-  5^•'• 

cemented      in      place 

(Fig.  593) ;  or  a  small  modified  Hammond  splint 
may  be  employed. 

Dislocation  of  Unerupted  Teeth. — A  developmg 
tooth  may  be  partially  dislocated  by  an  injury 
received  while  it  is  still  buried  in  its  crypt. 
In  such  cases,  the  part  of  the  tooth  already 
calcified  is  forced  out  of  its  proper  alignment 
with,  and  partially  detached  from,  the  re- 
mamder  of  the  tooth  yet  uncalcified,  thus  giving 
rise  to  certain  forms  of  dilacerated  teeth  (see 
p.  49). 

FRACTURE 

The  causes  of  fracture  of  the  teeth  are 
similar  to  those  producing  the  injuries  just 
described.  Teeth  undermmed  by  caries,  and 
those  possessmg  large  fillings  placed  in  im- 
properly prepared  cavities,  are  often  fractured 
by  biting  upon  hard  substances,  especially  when 
they  are  pulpless  :  occasionally  perfectly  sound 
teeth  may  be  fractured  in  the  same  manner. 

The  degree  of  injury  shows  considerable 
variation.  A  mere  crack  in  the  enamel  may  be 
disregarded,  and  a  slight  chip  simply  requires 
to  be  smoothed  down  with  a  stone  and  then 
polished. 

More  extensive  lesions  may  be  grouped  as 
follows:  (1)  Transverse,  (2)  Oblique,  and  (3) 
Longitudinal  fractures. 

Transverse  fractures  may  occur  in  the  crovra 
or  in  the  root ;  in  the  former  the  pulp  may  or 


527 


may   not  be  exposed,  whilst  in  tlie  latter  an 
impacted  fracture  is  sometimes  produced. 

Oblique  fractures  may  involve  the  crown 
only,  or  both  crown  and  root.  The  pulp  may 
or  may  not  be  exposed. 

Longitudinal  fractures  are  comparatively 
rare,  and  are  met  with  more  frequently  in  the 
premolar  and  molar  regions. 

In  the  treatment  of  these  cases,  the  extent 
of  the  lesion,  if  any,  suffered  by  the  soft  tissues 
of  the  dental  pulp  is  a  matter  of  first  importance, 
for  it  must  be  remembered  that  a  tooth  that  has 
been  fractured  has  been  concussed  also,  and 
although  the  pulp  may  not  have  been  exposed, 
due  observation  must  be  made  for  subsequent 
changes  in  that  organ,  such  as  described  under 
"  concussion  "  and  "  dislocation  ". 

Further,  the  pulp  of  the  tooth  may  be  directly 
exposed  by  tlie  line  of  the  fracture  rumiing 
across  it.  In  the  event  of  such  fracture  involving 
the  crown,  the  patient  sliould  be  anaesthetized, 
and  the  pulp  removed.  A  general  anaesthetic, 
such  as  nitrous  oxide,  is  to  be  preferred  as  a 
rale  to  a  local  anaestlietic,  altliough  in  some  cases 
of  anterior  teeth  an  injection  of  the  latter,  high 
up  near  the  apical  foramen,  may  serve.  It 
frequently  happens,  however,  that  some  peri- 
odontitis is  present,  and  under  these  circum- 
stances the  action  of  a  local  anaesthetic  is  not 
so  efficacious  as  one  would  wish.  Again, 
pressure  anaesthesia  is  difiicult  to  employ, 
inasmuch  as  there  is  no  cavity  in  which  to 
place  the  medicament  and  the  unvulcanized 
rubber,  by  means  of  which  the  necessary 
pressure  is  exerted.  The  root-canals  are  then 
treated  in  the  usual  manner,  and  the  missing  i 
portion  of  the  crown  is  restored  by  means  of  a 
filling,  inlay,  or  crown,  as  the  extent  of  the 
injury  necessitates. 

Again,  the  treatment  may  be  complicated 
stLU  further,  owing  to  the  age  of  the  patient 
and  the  fact  that  the  root  of  the  tooth  may  not  ' 
be  fuUy  formed.  In  the  case  of  an  upper  front 
tooth  it  is  desirable,  from  many  points  of  view,  1 
that  the  root  should  be  retained  if  possible. 
The  pulp  having  been  removed,  an  examination 
of  the  canal  should  be  made  with  a  fine  broach 
to  determine  the  length  of  the  root  and  the 
degree  to  which  the  apical  foramen  is  closed. 
If  the  apical  foramen  is  found  to  be  compara- 
tively  small,  an  attempt  should  be  made  to  fiU  ' 
the  canal,  either  by  a  "sponge  graft"  (2)  or 
one  of  the  methods  described  on  p.  481.  Fail- 
ing this,  the  tooth  must  be  removed,  and  as  a 
general  rule  means  should  be  taken  to  preserve 
the  space,  in  order  that  an  artificial  substitute 
may  be  inserted  at  a  later  date.  This  may  be 
done  by  adapting  two  metal  bands  of  the 
Angle  type  to  the  adjacent  teeth  and  uniting 
them  by  a  crossbar,  the  whole  being  cemented 
in  position  (Fig.  594).     When  the  tooth  involved 


space  may  sometimes  be 
in  the  mouth  of    a  boy 


Fio.  594. 


is  a  lateral  incisor  the 

allowed  to  close,  e.  g. 

when  there  is  evidence 

that   there   will    be   a 

general    crowding    of 

the  teeth.     The  fact. 

however,  that  the  loss 

of  such  a  tooth  would 

lead  to  a  driftmg   of 

the     central    incisors 

from  the  median  line  of  the  face,  must  be  borne 

in  mind,  and,  if  possible,  steps  should  be  taken 

to  minimize  this  by  the  judicious  extraction  of  a 

premolar  on  the  opposite  side.     A  similar  injury 

to  a  lower  incisor  in  the  mouth  of  a  young 

patient  is  best  treated  by  extraction  and  allowing 

the  space  to  close  naturally.     Its  loss  is   not 

very  noticeable  subsequently,  although  it  is  true 

that    it   may   lead    to    some   abnormalities    of 

position  of  the  teeth  in  the  upper  arch. 

When  the  fracture  is  trivial  in  extent,  involv- 
ing but  a  small  portion  of  the  incisal  edge  of  an 
upper  front  tooth,  it  is  possible  in  a  young 
patient  to  elongate  the  affected  tooth  by 
mechanical  means,  trim  the  ragged  edge  with  a 
stone  in  the  engine,  and  bring  the  tooth  into 
alignment  with  its  fellows.  A  simple  appliance 
for  such  purpose  consists  in  banding  the  fractured 
tooth  as  well  as  its 
immediate  neigh- 
bours, and  applying 
traction  force  by 
means  of  a  rubber 
band  as  shown  in 
Fig.  595.    It  is  neces-  P'ik.  .■)itr). 

sary    to    retain    the 

tooth  in  its  new  position  for  some  time,  as  other- 
wise it  tends  to  relapse  into  its  original  place. 

Agam,  a  small  fracture  of  the  incisal  edge  of  a 
central  incisor,  when  both  centrals  are  longer 
than  the  laterals,  may  be  treated  by  truemg  the 
edge  of  the  one  fractured  and  reducmg  the 
length  of  the  other  to  matcli. 

Transverse  fractures  through  the  root  of  a 
tooth  usually  demand  treatment  by  extraction. 
Wien  the  fracture  occurs  in  an  incisor,  but 
slightly  above  the  neck  of  the  tooth,  it  may  be 
possible  to  adapt  a  crown ;  in  such  a  case  no 
attempt  should  be  made  to  employ  one  of  the 
banded  varieties,  a  much  better  chance  of 
success  bemg  afforded  by  one  of  a  porcelain 
type,  "  flush  "  fitted.  WTien  the  fracture  occurs 
in  the  upper  third  of  the  root,  it  is  commonly 
accompanied  by  partial  dislocation  of  the 
remainder  of  the  tooth,  as  already  mentioned. 
Occasionally,  however,  there  is  complete  im- 
paction, and  under  such  circumstances  reunion 
may  take  place,  the  uniting  tissue  being  derived 
partly  from  the  pulp  and  partly  from  the  peri- 
odontal membrane ;  the  length  of  service  rendered 
by  such  teeth,  however,  is  comparatively  short. 


528 


Storer  Bemiett  (1)  has  described  a  case  of 
united  fracture,  which  occurred  in  the  practice 
of  W.  E.  Harding.  Tlie  patient  was  a  girl  aged 
seventeen  years  wlio  in  falling  struck  an  upper 
incisor  tooth,  whicli  was  driven  upwards  into 
its  socket,  and  fractured  obliquely  at  the  neck ; 
it  remamed  impacted  for  ten  months,  until  it 
caused  so  much  irritation  that  its  removal  was 
called  for.  A  microscopic 
examuiation  showed  that 
reunion  of  the  fracture 
had  taken  place,  the  unit- 
ing substance  consisting 
of  a  calcified  material  of 
a  spongy  or  cavernous 
character,  with  numerous 
spaces  for  blood-vessels. 
The  cavernous  spaces  had 
apparently  been  occupied 
by"a  substance  somewliat  resembling  pulp.  In 
various  positions  slight  absorption  of  the  edges  of 
the  normal  dentine  had  taken  place,  the  spaces 
thus  formed  being  filled  « ith  cementum.  showing 
well-marked  lacunae  and  canaliculi.  (See  Fig.s. 
596,  597,  598.) 


pain,  however,  caused  the  patient  to  consult 
Mr.  Tomes,  who  removed  the  tooth,  an  examina- 
tion of  which  revealed  the  fact  that  the  pulp 


Fig.  59(i. 
{Trans.  Odont.  Soc. 


{Trans.  Odont.  Soc.) 

Very  occasionally,  a  pulp  laid  bare  by  fracture 
of  the  tooth  undergoes  repair  by  calcification 
of  the  exposed  surface.  Charles  Tomes  (3)  has 
recorded  such  a  case.  In  attempting  the 
removal  of  a  lower  molar,  the  tooth  was  fractured 
slightly  below  its  neck,  thereby  producing  a 
large  exposure  of  the  pulp.  Tlie  remauider  of 
the  tooth  was  allo^^•ed  to  remain,  where  it  gave 
but  little  trouble  for  three  years.     Paroxysmal 


Fig.  598. 


{Trans.  Odont.  Soc.) 

had  not  died,  and  that  its  exposed  surface  had 
become  completely  calcified  over  with  secondary 


Fig.  599. 

{Trayu.  Odont.  Soc.) 

dentine,  in  which  were  embedded  several  minute 
pieces  of  fractured  dentine  (see  Fig.  599). 

M.  F.  H. 

BIBLIOGRAPHY 

(1)  Bennett,  C.  Storer.     Trans.  Odont.  Soc,  1S95-Q6, 

Vol.  xxviir,  p.  181. 

(2)  Brttnton,    G.      Jour.    Brit.    Dent.    Assoc,    1892, 

Vol.  XIII,  p.  352. 

(3)  Tomes,   C.   S.    Trans.    Odont.   Soc,    1895-96,  Vol. 

XXVIII,  p.  183. 


CHAPTER  XXXII  r 

THE  MECHANICAL   STRESSES   OF  MASTICATION 


In  considering  tlie  amount,  incidence,  and 
effects  of  the  mechanical  stresses  to  whicli  the 
teeth  are  subjected  in  the  process  of  mastica- 
tion, it  is  important  to  bear  in  mmd  that  each 
dental  arch  must  be  viewed  both  as 

(1)  a  unit  in  itself;  and 

(2)  an  aggregation  of  16  units. 

Stresses  applied  at  certain  positions  of  the 
arch  tend  to  wear  and  displace  the  units  upon 
which  they  act ;  but  when  the  full  complement 
of  teeth  remaui  in  normal  occlusion,  there  are 
compensating  resistances  in  other  parts  of  the 
arches,  which  tend  to  minimize  these  evil 
effects,  and  which,  together  with  the  mutual 
support  afforded  to  each  other  by  well-placed 
teeth,  enable  the  arch  in  proportion  to  its 
perfection  to  approximate  to  the  condition  of 
a  single  rigid  masticating  mechanism. 

IN    NORMAL    ARCHES    AND    UNDER   NORMAL 
CONDITIONS 

A. — The  amount  of  the  mechanical  stress  to 
which  the  teeth  may  be  exposed  when  the 
bite  Ls  closed  has  been  estimated  by  the  gnatho- 
dynamometer  and  found  to  be  (on  an  average  of 
1000  cases)  171  lb  in  the  molar  region  and,  of 
course,  somewhat  less  in  the  mcisor  region.— 
Black. 

The  maximum  possible  j)ressure  is  rarely 
reached,  and  the  slightest  condition  of  tender- 
ness of  the  teeth  dimmishes  at  once  the  force 
voluntarily  exerted  by  means  of  the  muscles 
of  mastication.  On  the  other  hand,  the  figures 
ascertained  by  a  dynamometer  are  misleading 
as  clinical  guides,  since  the  teeth  are  necessarily 
separated  more  or  less  by  the  msertion  of  the 
instrument,  and  the  pressure  recorded  is  there- 
fore less  than  the  true  maximum  force  of  the 
bite,  because  the  muscles  act  at  the  greatest 
mechanical  advantage  -when  the  teeth  are  at 
the  point  of  closure. 

Moreover,  such  measurements  as  have  been 
made  relate  to  the  vertical  movement  of  the 
mandible,  and  this  is  less  important  clinically 
than  movements  other  than  vertical,  the 
stresses  of  which  are  even  more  difficult  to 
measure. 

B. — The  direction  of  impact  of  stresses. 

(1)  In  the  Incisor  Region. — Here,  the  stresses 
to  which  the  teeth  are  subjected  are,  in  the  main, 


lateral  stresses,  and  owuig  to  the  natural  over- 
bite they  are  exercised  on  the  palatal  aspects 
of  the  upjDer  and  the  labial  aspects  of  the 
lower  teeth. 

Any  pressure  exercised  on  an  oblique  surface 
can  be  resolved  into  two  components — one 
parallel  with,  and  the  other  at  right  angles  to, 
the  oblique  surface,  in  this  case  formed  by  the 
palatal  aspect  of  the  upper  mcisor  crowns.  The 
first  component  (AB,Fig.  600)  can  be  neglected  as 
of  no  effect  as  a  stress  on  the  ui^ijer  tooth,  and  the 
cumulative  effect  of  the  second  (AC)  is  sho\vn 
in  the  later  years  of 
life  in  the  gradual 
moving  forward  and 
spacing  of  the  uf)per 
teeth,  and  often  in 
the  gradual  moving 
backward  and 
crowdmg  of  the 
lower  teeth. 

The  effect  is  more 
pronounced  in  the 
upper  than  the  lower 
teeth,  since  in  the 
latter  the  units  of 
the  arch  are  com- 
pressed together  and 
so  support  one  an- 
other. 

(2)  In  the  Pre- 
molar and  Molar 
Regions.  Here,  also, 
owing  to  the  obli- 
quity of  the  cusp 
surfaces,  any  stress 
is  split  up  into  com- 
ponents parallel  to 
and  at  right   angles 

with  the  cusp  surface,  and  the  latter  com- 
ponents similarly  tend  to  lessen  the  stability 
of  the  tooth.  That  this  effect  is  consider- 
able is  shown  by  the  way  in  which  the  buccal 
cusps  of  the  lower  molars  and  the  palatal 
cusps  of  the  upper  molars  are  worn  away 
when  the  teeth  have  been  subjected  to  much 
attrition. 

In  the  operation  of  masticating  on,  say,  the 
right  side  of  the  mouth,  the  mandible  is  carried 
to  the  right  and  the  teeth  are  closed,  bringmg 
the  outer  and  inner  cusps  of  the    molars  and 
529 


Fig.  goo. 


530 


the  outer  cusps  of  the  premolars  first  together 
(see  Fig.  601). 

The  outer  cusps  of  the  lower  teeth  then  slide 
up  to  the  sulcus  of  the  uppers,  whilst  their 
ioner  cusps  slide  up  the  lingual  aspect  of  the 


Fig.  601. 


inner  cusps  of  the  uppers.  The  slidmg  contact 
between  the  inner  cusps  usually  takes  place 
in  the  molar  region  only,  since  the  inner 
cusps  of  the  premolars  are  too  short  to  make  a 
contact  in  this  part  of  the  movement. 


Fig.  602. 

When  the  outer  cusps  of  the  lowers  have 
reached  the  upper  sulcus,  the  teeth  are  in  the 
position  of  the  resting  bite  (see  Fig.  602).     But 
the   sliding  movement  may  be  contmued  in 
the   same  direction,  and   the    contact  trans- 
ferred to  the  lingual  aspect  of  the  outer  cusps 
of  the  lower  teeth  and  the  buccal  aspect  of  the 
inner  cusps  of  the  upper  teeth.     This  contact 
is  shared  also  by  the  premolars,  smce  it  can  be 
made  when  the  longer  cusps  of  both  upper  and 
lower  teeth  are  articulating.     The   movement 


ends  with  apical  contact  between  the  lingual 
upper  cusps  and  the  buccal  lower  cusps. 

The  foregoing  description  deals  with  what 
takes  place  on  the  side  of  the  mouth  employed 
m  mastication.  But  during  this  movement 
the  teeth  are  also  in  contact  on  the  opposite 
side,  and  the  various  contacts  take  place  m  an 
order  the  reverse  of  that  described  above  (see 
Fig.  601).  Commonly,  however,  the  contacts 
are  less  numerous  on  the  non-masticating  side, 
owing  to  the  descent  of  the  condyle  on  that 
side. 


Fig.  603. 

These  stresses  regularly  at  work  show  them- 
selves in  time  in  the  wear  on  both  sides  of  the 
lingual  upper  and  buccal  lower  cusps. 

In  the  same  movement  there  Ls  contact  first 
between  the  tips  of  the  upper  and  lower 
canines,  then  between  the  medio -lingual  surface 
of  the  upper  canine  and  the  disto-huccal  surface 


Fl.:,    (id  I. 


of  the  lower,  resulting  in  wear  of  these  cusps  and 
surfaces  ;  and  also  a  sliding  contact  (from  side  to 
side)  resulting  in  wear  of  the  palatal  aspects  of 
the  upper  incisors  and  the  lingual  aspects  of 
the  lower.     These  latter  effects  become  more 


531 


marked  as  the  wear  of  the  molars  allows  of 
more  forcible  contact  between  the  upper  and 
lower  front  teeth. 

It  will  be  seen  that  while  the  stresses  on  the 
molars  and  premolars  are  bilateral  (outwards 
and  ui wards  in  both  upper  and  lower),  and  so 
tend  to  neutralize  one  another,  the  stresses  on 
the  canines  and  incisors  are  unilateral  (out- 
wards in  the  upper  and  inwards  in  the  lower 


Fig.  605. 

teeth).  Hence  displacement  of  the  premolars 
and  molars  is  rare  in  normal  dentures,  while 
displacement  of  the  front  teeth  may  occur  in 
any  denture  after  wear  or  loss  of  the  back  teeth 
has  allowed  undue  approximation  of  the  jaws. 
This  will  always  be  slight  in  a  normal  and 
complete  denture,  but  is  rendered  much  more 
obvious  under  abnormal  conditions  to  be  sub- 
sequently dealt  with. 

Fig.  •iO(i. 

E.xamples  of  tlie  wear  of  teeth  that  ultimately 
takes  place  under  the  masticating  stress  in 
nearly  normal  dentures  is  shown  in — 


Fig.  COS,  3  .  rig. 604,  53,; 


Fig.  605,  jS  ]    and  Fig.  606, 


Note  that  in  the  upper  canines  the  stresses 
are  such  as  to  exert  pressure  from  the  median 
line,  and  in  the  lower  canines  towards  the 
median  line  of  the  mouth. 


Attention  has  been  drawn  to  the  fact  that 
the  stability  of  the  molar  and  premolar  teeth  in 
the  perfect  arch  is  due  to  the  lateral  stresses 
upon  them  being  alternately  inward  and  out- 
ward in  both  upper  and  lower  teeth,  the  forces 
thus  tending  to  neutralize  each  other ;  while 
the  evil  effects  of  the  unilateral  outward  and 
inward  stresses  upon  the  upper  and  lower 
front  teeth  respectively  are  only  limited  by  the 
closure  of  the  back  teeth  determining  the 
amount  of  stress  that  can  fall  on  the  front. 

UNDER    ABNORMAL   CONDITIONS 

A. — Effects  of  malposition  on  the  incidence  and 
amount  of  stivss  cui  indixidual  units  of  .m  ai'ch. 


Fig.  607. 

These  are  seen — 

(1)  In  the   increased   wear  of  cusps 
malpoised  teeth. 

Fig.  607  is  a  case  where  the  deciduous  canmes 
were  unduly  long  as  compared  with  the  other 


the 


Fig.  608. 

teeth,  and  being  thereby  subjected  to  an  ab- 
normal amount  of  ^Dressure  at  the  commence- 
ment of  the  lateral  movement  of  mastication, 
became  worn  at  the  tips,  and,  in  the  lower 
canines,  on  the  disto-labial  aspect. 

Fig.  608  shows  the  effect  of  increased  lateral 


532 


stress  due  to  slight  local  irregularity,  resulting 
in    a    little    forward  displacement    of  |  1    and 

marked  labial  wearing  of  |  1. 

(2)  In  the  increase  of  the  malposition,  or  in 
its  recurrence  if  rectified,  owing  to  the  abnormal 
stress  exercised  at  that  point,  or  to  the  greater 
range  or  length  of  time  over  which  the  stress 
is  applied. 

When  cases  of  superior  protrusion  were 
treated  by  merely  drawing  the  upper  incisor 


crowns  back  without  reducing  the  long  over- 
bite of  the  front  teeth,  relapse  was  quite  usual. 

Here,  the  condition  represented  in  Pig.  609  (I) 
was  changed  to  that  shown  in  Fig.  609  (II) ,  and 
the  lateral  stresses  exercised  over  the  long  sliding 
contact  from  A  to  B  speedily  drove  the  upper 
incisors  forward  again.  But  when  the  bite  of 
the  back  teeth  is  raised,  or  the  upper  incisors 
are  driven  uj)wards  as  well  as  backwards,  and 
the  overbite  in  front  is  thus  reduced,  the  condi- 
tion is  as  shown  in  Fig.  609  (III) ,  -where  the  chance 
of  relapse  is  much  less  owing  to  the  lateral  stress 
bemg  limited  to  its  normal  range  of  action. 

The  tendency  of  upper  incisors  to  move 
forward  if  the  stress  upon  their  palatal  surfaces 
becomes  too  great  applies  equally  of  course  to 
artificial  incisor  crowns. 

It  is  frequently  seen  that  in  Logan  crowns, 
where  the  pin  is  often  made  of  platinum  too 
soft  for  the  purpose,  the  stress  has  been  sufficient 
to  bend  the  pin,  the  crowna  has  been  tilted 
forwards,  and  its  palatal  margin  raised  from 
the  end  of  the  root.  This  tendency  is  often 
dealt  with  by  adjusting  the  crowii  so  that  its 
palatal  aspect  clears  the  bite  altogether;  but 
such  provision  is  likely  to  be  of  only  temporary 
effect,  smce  the  root  will  probably  descend 
from  the  socket  till  the  crown  meets  the  lower 
incisor  bite. 

To  counteract  the  double  tendency  to  gradual 
lengthening  and  displacement  forwards,  the 
provision  of  a  small  palatal  cusp  to  the  crown 
has  sometimes  been  practised.     When  the  bite 


is  closed  this  cusp  articulates  on  the  lingual  side 
of  the  cutting  edge  of  the  lower  incisor,  and 
obviously  prevents  the  upper  crown  from  moving 
forward  and  lengthening. 

The  tendency  of  crown-posts  to  bend  or 
break  under  lateral  stress,  or,  where  the  post 
itself  withstands  the  stress,  the  tendency  of  the 
root  to  split,  furnishes  the  reason  for  the 
addition  of  a  collar  round  the  root  or  a  partial 
collar  on  its  palatal  aspect.  The  need  for  collars 
in  addition  to  posts,  would  seem  to 
be  greater  in  the  incisor  region, 
where  the  stress  is  unilateral,  than 
in  the  premolar  region,  where  it  is 
alternately  outwards  and  inwards. 
Another  effect  of  lateral  stresses 
is  seen  m  the  splitting  off  of  one 
~ "  cusp  of  a  weakened  tooth,  e.  g. 
where  an  upper  premolar  has  large 
medial  and  distal  cavities  joining 
each  other  across  the  masticating 
surface,  through  caries  in  the 
sulcus.  In  such  cases  the  fracture 
is  produced  by  the  wedging  of 
food  particles  between  the  cusps 
of  the  weakened  tooth. 

Fig.  610  shows  a  method  of  filUng 
designed  to  avoid  this  accident. 
The  lingual  cusp  is  cut  down  sufficiently  to  allow 
the  filling  material  to  be  extended  over  it,  and 
stUl  to  leave  a  space  between  itself  and  the  mner 
cusp  of  the  lower  premolar.  From  this  space 
the  food  particles  can  escape  in  a  lingual 
dnection,  and  so  injurious  wedging  is  avoided. 
The  outer  cusp  of  the  up- 
per premolar  is  cut  away 
lingually,  so  that  the  bite 
of  the  outer  cusp  of  the 
low  er  is  borne  by  the  filling 
material,  and  the  stress 
taken  off  the  upper  cusji. 
B. — Effects  of  loss  of 
some  of  the  units  of  one 
arch  on — 

(1)  The  remaining  units 

of  that  arch. 

(2)  Tlie  various  units  of 

the  opposing  arch. 

(1)  ^\'Tien  some  of  the 
units  in  an  arch  are  lost, 
there  is  obviously  an  in- 
crease in  the  stresses  on  the  remaining  units, 
owing  to  the  lesser  number  over  which  the 
stresses  are  distributed. 

This  results  in — • 

(a)  Greater  wear  of  the  remaming  units. 

(b)  Movement  in  position  of  some  of  or  all  the 

remaining  units,  owing  to  increased 
stresses  and  loss  of  lateral  contact 
with  other  units  of  the  arch. 


Fig.  610. 


533 


Where  both  upper  and  lower  first  molars 
have  been  lost  from  tlie  same  side,  the  inter- 
action of  the  cusps  of  the  premolars  on  the 
inclined  planes  of  their  opponents  soon  causes 
separation  and  backward  displacement  of  these 
teeth ;  for  this  to  occur,  however,  both  upper 
and  lower  premolars  must  be  free  to  move. 
If  either  upper  or  lower  first  molar  is  retained, 
and  the  premolars  in  front  of  it  are  tliereby 
kept  in  proper  position,  the  stresses  exerted 
by  these  will  in  turn  preserve  their  opponents 
from  backward  disijlacement,  notwithstanding 
the  absence  of  the  opposing  first  molar. 

(c)  Tendency  to  loosening  of  the  various 
units,  owing  to  the  increased  stresses, 
both  lateral  and  vertical. 

(2)  In  the  opposite  arch,  the  units  that 
have  lost  their  opponents  tend  to  elongate. 
Since  these  elongated  teeth  may  be  not  corn- 


ward  the  upper  incisors  acts  by  wearing  exten- 
sively the  labial  surfaces  of  the  lower  incisors. 


Fig.  lill. 

pletely  unopposed,  there  are  developed 
abnormally  long  slidmg  contacts  between 
them  and  partially  opposing  teetli.  This 
means  that  the  lateral  stress  is  here  in- 
creased in  the  range  of  its  action ;  and 
abnormal  wearmg  or  loosening  results. 

Fig.  611  shows  a  case  where  the  front 
teeth  developed  an  abnormally  long  over- 
bite, owing  to  loss  of  opposition  between 
upper  and  lower  back  teeth.  As  the  over- 
bite in  front  became  deeper  and  deeper, 
tlie  lateral  stresses,  outwards  m  the  upper 
and  inwards  in  the  lower,  came  to  act 
over  a  greater  and  greater  range  of  sliding 
contact ;  as  well  as  bemg  absolutely  in- 
creased on  these  teeth,  owing  to  the 
diminished  number  of  teeth  remaining. 
The  result  is  seen  in  the  unnatural  spacing 
of  3.2.1. 

Fig.  612  shows  tlie  lower  arch  of  the  same 
case.     Here  the  lateral  stress  that  forced  for- 


FiG.  Cil2. 

This  difference  in  the  effect  of  the  same  force 
acting  on  upper  and  lower  incisors  is  frequently 
seen,  since,  as  already  pointed  out,  it  is  much 
easier  to  force  the  units  of  an  arch  out  by 
pressure  from  withui,  than  to  force  them  in  by 
pressure  from  w  ithout.  So,  in  the  latter  case,  tlie 
force  rather  exhausts  itself  in  wearing  the  teeth. 

Fig.  613  shows  undue  approximation  of  the 
jaws  owing  to  loss  of  opposition  between  back 
teeth.  This  has  developed  increased  stresses 
in  the  incisor  and  canine  region,  resulting  in 
forward  movement  and  spacing  of  the  upper 
front  teeth.  It  also  shows  that  as  the  bite 
has  closed,  an  abnormally  long  slidmg  contact 
has_been  developed  between  the  distal  surface 
of  5  j  and  the  medial  surface  of  5  I  partly 
articulating  with  it.     The  displacement  back- 


FiG.  013. 

wards  of  the  latter  and  the  wearmg  away  of 
both  teeth  are  obvious. 


534 


It  is  to  be  remembered  that  the  lengthening 
of  a  tooth  may  be  actual  or  relative.  The  tooth 
may  be  actually  extruded  from  its  socket  owing 
to  loss  of  aU  its  opponents.  But  if  the  arch 
is  partly  supplied  by  artificial  teeth  on  a  plate, 
and  this  denture  slowly  "  rises  "  or  "  settles  " 
in  the  mouth,  owing  to  the  pressure  exerted 
by  opposing  teeth  and  the  gradual  absorption 
of  the  alveolar  ridge,  the  remaining  natural 
teeth  in  the  composite  arch  v,iR  become 
relatively  longer  than  their  artificial  companions, 
even  though  no  actual  extrusion  from  their 
sockets  has  occurred.  In  this  case  they  will 
encounter  the  force  of  the  bite  sooner  than  the 
teeth  on  the  plate,  and  durmg  the  part  of  the 
movement  in  which  they  supply  the  sole 
antagonism  to  the  opposing  teeth,  wUl  have  the 
stresses  upon  them  increased  owing  to  their 
smaller  number ;  and,  taking  the  wliole  range 
of  the  masticatory  movement,  it  wUl  be  of 
longer  duration  in  the  case  of  the  natural 
members  of  an  arch  than  in  the  artificial  ones, 
where  the  plate  has  sunk.  Hence  results  of 
abnormal  wear — displacement  and  loosening — 


Fig.  liU. 


are  likely  to  occur  amongst  these  natural  units 
of  the  arch. 

Fig.  614  shows  the  lack  of  opposition  amongst 
back  teeth  which  may  be  caused  by  the  rising 

and    sulking    of    plate    dentures.     Here      "  " 


are  artificial  teeth  on  plates.  The  space  be- 
tween the  molars  caused  by  smking  of  plates 
does  not  exist  between  5  |  and  5  |  ,  because 
the  latter  tooth  was  added  later  as  a  repair,  and 
was  placed  at  a  higher  level  than  6  |  and  7  |  so 
as  to  be  in  articulation  with  the  upper.  Of 
course  6  |  and  7  |  should  have  been  raised 
at  the  same  time. 

rig.  615  shows  virtual  or  relative  elongation 


of  I  3  and  |  6,  owing  to  the  rising  of  an  upper 
plate  carrying  artificial  incisors  and  premolars. 
Here  the  closing  of  the  bite  has  allowed  an 
abnormally  long  sliding  contact  to  develop 
between    |  3  and    |  3,  resulting  in  great  wear  of 

the  disto-labial  aspect  of  |  3,  and  in  medio- 
palatal wear  and  loosening  of  |  3,  though  these 
latter  points  cannot  be  verified  from  the  figure. 


Fig.  615. 

Such  cases  show  the  results  of  a  method  of 
artificial  replacement  that  allows  of  actual  or 
relative  lengthening  of  the  remaining  natural 
teeth,  and  the  consequent  development  of  in- 
creased lateral  stresses  ui^on  them.  To  over- 
come these  is  one  of  the  objects  of  bridge-work, 
which  transmits  the  stress  of  mastication  to  the 
roots  of  natural  teeth  on  which  it  is  mounted, 
instead  of  to  the  surface  of  the  slowly  atrophymg 
alveolar  ridge. 


STRESSES    OF    MASTICATION    IN 
TO   BRIDGE-WORK 


RELATION 


It  is  not  intended  here  to  discuss  the  whole 
of  the  advantages  or  disadvantages  of  bridge- 
work,  but  only  to  examine  them  in  relation 
to  the  stresses  of  mastication  and  their  effects. 

It  is  evident  that  so  long  as  a  bridge  lasts,  it 
can  more  efficiently  perform  its  proportional 
share  of  the  work  of  the  arch  than  can  substi- 
tutes on  a  plate.  Its  level,  as  compared  with 
the  natural  teeth,  will  not  change,  and  so  these 
are  not  exposed  to  the  increased  stresses,  with 
consequent  wear,  displacement,  and  loosening, 
which  follow  the  actual  or  relative  lengthen- 
ing of  natural  teeth  when  a  partial  plate  is 
used. 

But  bridge-work  has  the  great  disadvantage 
that  the  stresses  of  mastication  are  trans- 
mitted to  a  smaller  number  of  roots  than  were 
intended  by  Nature  to  bear  them,  and  so  it  is 


535 


found  that  the  roots  upon  which  the  bridge  is 
mounted  ultimately  loosen,  and  the  work  is 
rumed. 

As  m  the  case  of  natural  teeth,  so  in  the 
roots  upon  which  a  bridge  is  mounted,  the  lateral 
stresses  are  those  that  chiefly  operate  hi  loosen- 
ing the  roots ;  and  these  can  best  be  combated 
by  extending  the  bridge  as  far  as  possible 
round  the  arch,  thus  increasmg  the  number 
of  its  root  supports,  and  arranging  that  these 
shall  not  be  in  a  straight  line  or  slight  curve, 
but  shall  be  so  placed  that  the  appliance  has  the 
stability  of  a  "three-legged  stool",  or  better 
stiU,  of  one  with  more  than  three  legs. 

Thus,  two  antero-posterior  bridges  should  not 
be  placed  at  the  sides  of  the  jaw ;  they  should 
be  connected  across  the  middle  line.  An  in- 
cisor, or  incisor  and  canine,   bridge  should,  if 


Fig.  (iia. 

possible,  be  prolonged  round  the  jaw,  and  take 
in  some  tooth  in  the  premolar  region  of  one  or 
both  sides.  In  this  way  the  whole  bridge  will 
not  be  expo.sed  to  the  force  of  mastication  at 
the  same  time  ;  and  the  portion  remote  from 
the  site  of  stress  will  liave  some  of  that  stress 
transmitted  to  it,  and  will  serve  to  support 
and  "  key  "  the  portion  of  the  bridge  that  is 
exposed.  The  adoption  of  this  plan  will  in- 
crease the  number  of  roots  over  which  the  stress 
is  distributed,  and  must  materially  lengthen 
the  life  of  the  work. 

The  history  of  the  case  shown  in  Fig.  616 
illustrates  some  of  the  points  made  in  the  fore- 
going statement. 

The  patient  is  a  smoker  who  has  for  years 
been  in  the  liabit  of  holding  his  pipe  with  the 
left  incisors  and  canines.  The  combhied  loosen- 
ing efifects  of  tlie  masticating  stresses,  the  pipe 
stresses,  and  alveolar  absorption,  caused  first 
the  loss   of     I  1.2,   which   were  replaced  by  a 


small  lower  plate.  Then  1  |  also  loosened,  and 
the  lower  bridge  was  uiserted,  by  means  of 
which  5.1  I  1.2  were  supported  on  4.3  |  3.  All 
the  upper  and  lower  molars  were  subsequently 
lost  and  replaced  by  dentures,  the  lower 
denture  also  replacing  |  5.  Then  followed  the 
loss  of  I  2,  which  was  replaced  by  the  bridge 
shown  in  the  figure,  by  means  of  which  |  2  was 
supported  by  |J^.3,  and  which  was  inserted 
about  three  years  later  than  the  lower  bridge. 

The  teeth  supportmg  the  upper  bridge  soon 
loosened,  so  that  the  appliance  failed  altogether 
and  had  to  be  removed  The  natural  teeth  and 
bridge  are  included  in  the  model. 

The  lower  bridge  has  remahied  firm  and 
satisfactory  throughout,  and  has  been  in  use 
some  years  longer  than  the  upper.  Its  extent 
has  been  indicated  by  colouring  the 
metal  parts  on  the  model,  the  bridge 
itself  bemg  still  in  the  patient's  mouth. 
There  are  several  reasons  for  this 
failure  and  success.  Firstly,  as  has 
been  pointed  out,  the  loosening  and 
displacing  effects  of  the  lateral  stresses 
are  more  marked  iia  upper  than  in 
lower  front  teeth,  since  it  is  easier  to 
dislodge  the  segments  of  an  arch  by 
pressure  from  within  than  from  with- 
out. Secondly,  since  the  upper  bridge 
is  the  shorter  and  is  at  one  side  of 
the  mouth  only,  it  is  more  likely  that 
the  whole  of  the  bridge  will  be  acted 
upon  by  stress  at  any  one  time,  than 
would  be  the  case  if  an  extension 
passed  across  tlie  middle  Ihie.  Thirdly, 
nearly  aU  the  stress  on  such  a  bridge 
wiU  be  of  the  most  damaging  kind, 
namely,  unilateral  outwards  at  right 
angles  to  the  plane  of  the  palatal 
aspect  of  the  bridge. 

The  greater  permanence  of  the  lower  bridge 
is  accounted  for  by  the  following  facts.  Firstly, 
the  main  stress  on  the  bridge  is  from  without 
inwards,  which  cannot  have  so  great  a  loosen- 
ing effect  as  stress  ui  the  opposite  direction. 
Secondly,  the  bridge  is  prolonged  to  the  first 
premolar  on  the  right  side,  and  thus  lias  the 
"three-legged  stool  "quality;  though  the  arm 
of  the  bridge  from  3  |  to  4  |  is  shorter  than 
might  be  desired,  still  the  support  of  4  |  must 
be  very  efficacious  hi  counteracting  the  back- 
ward stress  on  the  front  teeth.  Thirdly,  the 
stresses  on  this  bridge  are  of  a  mixed  character. 
If  the  facets  visible  in  Figs.  608,  603,  604,  and 
605,  are  examined,  it  will  Ije  seen  that  they 
indicate  stresses  directly  backwards  on  the  lower 
incisors,  but  backwards  and  towards  the  middle 
line  on  the  lower  canines. 

Now,  all  the  stresses  applied  to  one  end  of 
a  bridge  in  the  direction  of  the  length  of  the 


536 


bridge  will  be  adequately  resisted  by  the 
supports  at  the  other  end.  It  is  manifest  that 
if  a  hurdle  is  implanted  by  two  stakes,  one  at 
each  end,  it  is  easier  to  throw  it  down  by  pres- 
sure applied  to  one  side  at  right  angles  with 
the  plane  of  the  structure,  than  to  one  end  in 
the  direction  of  the  other  end. 

All  the  pressures  acting  on  the  upper  bridge 
are  of  the  first  kind.  Pressures  of  this  kind 
in  the  lower  bridge  are  resisted  by  its  distal 
arm  fixed  to  4  |  and  ending  m  5  I  .  3  |  and 
3  form  supports  for  each  other  against 
"  end  on  "  stresses,  such  as  those  thrown  on 
the  lower  canines  in  normal  movements  of 
mastication. 

The  histories  of  this  and  other  cases  show 


conclusively  that  in  bridge-work  the  stability 
and  success  of  the  appliance  do  not  depend 
merely  upon  not  overloading  the  supporting 
roots  with  too  many  additional  artificial  teeth. 
The  success  depends  at  least  as  much  upon 
such  design  of  the  .structure  as  will  bmd  the 
supporting  roots  into  a  unity  of  form  calculated 
to  resist  most  efficiently  the  combined  wrecking 
stresses  from  all  sides  that  it  wUl  have  to  en- 
counter. In  the  above  case  the  upper  bridge, 
by  which  one  tooth  was  attached  to  two 
contiguous  ones,  proved  far  less  durable  than 
the  lower  one,  by  which  five  teeth  were  attached 
to  three. 

G.  G.  C. 
C.  H.  P. 


CHAPTER    XXXIY 

ARTIFICIAL  CROWNS 


GENERAL    CONSIDERATIONS 

Prefatory  Remarks. — Perhaps  the  most  fas- 
cinating field  in  the  domain  of  operative 
dentistry  is  that  of  crowning.  The  term  covers  j 
two  main  ideas :  first,  the  substitution  for  the 
natural  crown  of  an  artificial  one  fixed  on  the 
root ;  second,  the  covering  of  a  natural  crown 
by  a  fixed  cap  or  shell  of  metal  such  as  gold  or 
platinum. 

The  attractiveness  of  the  subject  is  due 
chiefiy  to  the  perfect  restoration  of  function, 
and  also,  when  desired,  of  normal  natural  ap- 
pearance tliat  is  attamable.  Added  to  these 
almost  unique  merits  is  the  interest  that  is 
excited  by  the  nature  of  the  technical  pro- 
cesses involved,  which  enter  into  all  the  refined 
arts  nowadays  brought  to  bear  on  operative 
prosthetic  dentistry.  Li  most  cases  of  crownmg 
the  result  may  be  expected  to  prove  of  a  durable 
nature,  even  when  the  natural  crown  is  in  such 
an  advanced  state  of  demolition  and  decay,  or 
total  loss,  that  any  other  operation  for  its 
restoration  would  give  but  a  very  poor  result 
or  be  entirely  impossible.  Appreciation  of 
such  an  operation  well  performed  is  a  feeling 
that  can  be  shared  alike  by  both  operator  and 
patient.  Again,  the  inherent  difficulties  of  the 
subject  provide  unlimited  scope  for  the  best 
efforts  and  ingenuity  of  the  most  skilled,  most 
inventive,  and  most  artistic  of  operators. 

The  restoration  of  both  function  and  natural 
appearance  to  the  point  of  perfection  that  is 
attainable  may  justly  be  said  to  place  this 
operation  of  crowning  in  the  position  of  being 
the  most  perfect  substitutive  operation  in 
surgery,  either  dental  or  general. 

Very  often,  teeth  that  have  become  the 
merest  wrecks,  and  that  may  have  been  filled 
and  refilled,  and  still  further  damaged  by  frac- 
ture and  caries  until  more  filling  is  a  hopeless 
proposition,  may  be  saved  from  their  otherwise 
derelict  condition  by  crowning,  and  thereby 
restored  to  a  condition  that  virtually  equals 
that  of  the  perfect  organ. 

Crowning  Compared  with  Filling. — A  crown, 
by  surrounding  a  root  or  part  of  a  tooth,  helps 
to  hold  the  particles  of  the  tooth  together, 
and  so  strengthens  it.  A  crown  also  takes 
its  attachment  from  the  strongest  remaining 
part  of  the  tooth.     A  filling,  on  the  other  hand, 

537 


is  in  a  much  less  advantageous  position,  because 
both  of  these  conditions  are  reversed. 

Relative  Merits  of  Crowning  and  Extraction 
Compared. — First  and  foremost  let  it  be  stated 
in  crownuig  versus  e.xtraction,  that  when 
crowning  is  likely  to  be  a  successful  operation, 
and  when  it  will  obviate  the  necessity  for  wear- 
ing a  plate,  it  is  of  such  enormous  advantage 
to  the  patient  that  no  words  can  be  too  strong 
to  express  condemnation  of  extraction.  Thus, 
the  operator  who  wUI  break  into  an  unbroken 
row  of  the  six  or  eight  front  teeth  in  the  mouth 
of,  say,  a  young  lady,  by  extracting  one  of  them 
for  some  remediable  defect,  such  as  exijosure 
of  jKilp,  or  fracture  of  the  crown,  or  primary 
acute  abscess,  deserves  to  be  severely  censured. 
The  tooth  could  be  satisfactorily  treated  with- 
out extraction  in  the  vast  majority  of  such 
cases,  and  the  operator  should  be  under  no 
delusion  as  to  the  absolute  truth  of  this  point 
of  view. 

With  regular  care  and  attention  on  the  part 
of  both  operator  and  patient,  it  should  become 
but  very  rarely  necessary  to  extract  a  firm 
tooth.  Crowning  should  be  resorted  to  when 
the  safety  of  the  root  would  otherwise  be  im- 
perilled, so  long  as  teeth  remain  tight  in  the 
jaw.  A  tendency  downward  on  the  path  of 
decay  and  dissolution  should  at  all  events  be 
arrested  by  cro«iiing ;  and  in  the  case  of  a 
young  person  the  wearing  of  a  plate  witli  artifi- 
cial teeth  should  but  rarely  be  allowed  to  become 
a  necessity.  With  this  end  in  view,  every 
tooth  should  be  crowned  as  soon  as  it  is  recog- 
nized that  further  filling  will  not  restore  it 
to  proper  and  permanent  function.  By  this 
means  extraction  will  be  obviated,  with  the 
possible  exception  of  the  third  molars,  which 
may  not,  as  a  rule,  be  worth  crowning.  If, 
however,  a  molar  has  already  been  lost  from 
the  same  range  of  molars,  then  at  all  events 
even  the  third  molar  is  well  worth  crowning. 

When  a  Partial  Plate  is  already  being  worn. 
In  those  cases  w here  a  plate  is  being  \\orn  and 
a  natural  tooth  breaks  down  in  the  vicinity 
of  the  plate,  the  question  arises  whether  it  is 
better  to  add  the  new  tooth  to  the  plate  or  to 
restore  the  tooth  by  cro\viiing.  In  the  case  of 
an  old  and  feeble  patient  it  will  often  be  in- 
advisable to  incur  the  discomfort  and  exhaustion 
attendant   upon   a   long   operation;   crowning. 


538 


therefore,  will  be  ruled  out ;  but  in  other  cases, 
crowTiing  will  generally  be  the  better  propo- 
sition.    The  reasons  for  this  are  as  follows — 

(a)  extraction  is  avoided  ; 

(b)  having  a  root  under  the  plate  is  avoided ; 

(c)  the  removal  at  night  of    this  particular 

tooth  is  avoided ; 

(d)  the  plate  is  steadied  and  supported    by 
the  presence  of  the  crown  ; 
good    crown   forms  the   best   kind   of 
abutment  for  the  embrace  of  a  clasp- 
band,  if  such  an  assistance  to  steadiness 

of  the  plate  is  desired,  partly  because 
the  crown  can  be  made  of  a  favourable 
shape  with  parallel  sides,  and  partly 
because,  inilike  a  natural  tooth,  a 
crown  is  not  liable  to  have  caries  induced 
by  the  band. 

If  not  crowned,  the  root  should  generally  be 
extracted. 


The  prematurely  senile  cast  of  countenance 
that  results  from  wholesale  extraction  and 
consequent  absorption  of  alveolar  processes 
is  well  known,  and  forms  a  strong  argument 
in  favour  of  crowning  as  against  extraction. 


(e)  a 


A  B 

Fio.  617. 

A.  Shows  the  regular  distribution  of  occlusal  force  over  the  whole 

socket   in   the   case   of  an   erect-standing   tight   tooth   and 
normal  occlusion. 

B.  Shows  the  increased  force  applied  to  one  side  of  the  socket  in 

the  case  of  an  obliquely  standing  tooth,  leading  to  premature 
loosening. 

The  disadvantages  of  leaving  a  root  under  a 
plate  are — 

(a)  the   liability  of  the  root  to  decay  and  to 

become  septic ; 

(b)  the  constant   tendency  of  the  root  to  be 

extruded,  causing  the  plate  in  time  to 
rock  upon  it ; 

(c)  the   increased   liabiUty   of    the   artificial 

tooth  to  get  broken,  owing  to  its  being 
nipped  between  the  root  on  the  one 
hand  and  the  occluding  tooth  on  the 
other. 


Fig.  618. — Site  of  extracted  tooth,  showing  gum  re- 
ceded from  cervix  of  neighbouring  t«eth,  exposing 
root. 

Few  people  will  require  argument  to  convince 
them  of  the  advantages  of  teeth  as  compared 
with  no  teeth ;  but  all  the  disadvantages  of 
losing  a  tooth  are  not  immediately 
apparent,  and  therefore  it  is  necessary 
to  mention  at  least  some  of  the  evils 
that  are  caused  by  extraction  to  neigh- 
bouring teeth. 

Firstly,  extraction  will  often  cause  the 
neighbourmg  teeth  to  fall  from  their 
normal  positions,  to  become  oblique  by 
tilting  towards  the  gap.  This  will  cause 
an  abnormal  contact  of  approximal 
surfaces  and  so  induce  caries.  It  will 
also  destroy  the  closeness  of  their  occlu- 
sion and  therefore  their  effectiveness  as 
part  of  the  masticatory  organ. 

Secondly,  extraction  will  be  likely  to 
cause  premature  loss  of  neighbouring 
teeth  by  loosening.  An  obliquely  leaning 
tooth  cannot  support  the  strain  of  the 
occluding  force  so  well  as  an  erect- 
standing  tooth ;  for  part  only  of  the 
socket  has  to  receive  the  force,  which 
should  be  distributed  over  the  whole  of 
it,  and  so  the  tooth  will  become  pre- 
maturely loosened  (see  Fig.  617). 

Thirdly,  extraction  damages  the  neigh- 
bouring teeth  by  causing  the  gum  and 
alveolar  process  to  recede  from  them, 
especially  on  the  side  of  each  tooth  towards 
the  vacancy,  thus  not  only  partly  depriving 
them  of  their  attachment,  but  also  uncovering 
a  surface  of  dentine  or  cementum,  which  may 
give  pain  and  trouble  through  its  sensitiveness 
and  is  specially  liable  to  caries  (see  Fig.  618). 
Fourthly,  extractions  are  detrimental  to  teeth 
in  tlie  occluding  jaw,  which  are  deprived  of 
their  antagonists,  and  wUl  on  that  account 
protrude  from  their  sockets  and  lose  their 
correct  level,  until  they  nearly  bite  the  gum 
of  the  opposite  jaw,  and  also  lose  part  of  their 
attachment. 


539 


Fifthly,  extraction,  by  reducing  the  numbec  | 
of  teeth,  greatly  aggravates  that  tendency  of  < 
the  rest  to  wear  down,  which,  especially  in  the   I 
mouths  of  strong  and  active  patients,  becomes 
so  often  a  troublesome  condition,  it  bemg  so 
difficult  to  arrest  and  treat. 

Pulplessness  not  a  Disadvantage. — The  condi- 
tion of    "  pulplessness ",  which   is  a   condition 
generally    presupposed    to    a    crowned    tooth, 
need  be  considered  no  detriment  to  its   "ex- 
pectation of  life  ",  so  far  as  its  retention  as  a 
useful    organ    is    concerned.     The    lesson   that 
experience  teaches  is  that  with  scrupulous  care 
in  the  treatment  of  root-canals  and  the  elimma- 
tion  as  far  as  possible  of  liability  to  sepsis  at 
the  apex  of  the  root,  the  pulpless  tooth  will 
last  quite  as  long  and  quite  as  efficiently  as  the 
live  tooth.     It  is  oidy  too  true  that  infection 
of  the  periodontal  membrane  will  cause  either 
acute  abscess  or  chronic  inflammation  of  the 
socket,   but   modern  instruments  and   modern 
methods  in  this  regard  have  arrived  at  such  a 
degree   of   efficiency   that   the   chance   of   this 
kind  of  uifection  can,  in  the  great  majority  of 
cases,  be  reduced  to  a  negligible  quantity.     If 
premature    loosening    of    a    dead    tooth    does 
happen,  it  is  probably  due  to  chronic  septic 
irritation  of  the  socket  set  up  by  decomposition 
at  the  apical  portion  of  the  canal,  or  to  arsenic - 
irritation  of  the  socket ;  and  not  to  the  7nere  fact 
of  the  tooth   being  pulpless.     The  writer   be- 
lieves   that     "dead"    teeth,    when    carefully 
treated    and    free    from    septic    contamination 
resist    the    loosening    that    might    result    from 
pyorrhoea  alveolaris,  and  also  from  what  may 
be  called  senile  atrophy  of  the  socket,  better 
than    teeth    with    living    pulps.     A    loosening 
similar   to   that    of   senile   atrophy   frequently 
attacks  the  teeth  of  persons  of  middle  age ;  but 
still  this  kind  of  loosening  seems  to  be  due  to 
no   other   cause   than   atrophy,    and   therefore 
senility,  so  far  as  the  tooth-socket  is  concerned, 
must  be  considered  to  have  arrived  prematurely. 
The    writer   has    observed    that    this    kind    of 
loosening  attacks  "  living  "  teeth  to  a  far  greater 
degree  than  "  dead  "  ones.     That  pulplessness 
qua  pulplessness  is  not  a  cause  of  premature 
loosening,  requires    but    one    instance    for    its 
proof.     Here    it    is  :    An    old    gentleman    pre- 
sented himself  first  to  the  writer  at  eighty  years 
of  age,  with  all  his  front  teeth  still  in  his  mouth. 
One  of  these  had  been  "pivoted"  fifty  years 
before,  i.  e.  crowned  with  a  metal  post  inserted 
in  the  enlarged  root-canal  to  its  apex.     All  the 
teeth  at  the  time  of  his  presentmg  himself  were 
loose  ;  but  the  "pivoted  "  tooth  was  the  tightest 
of  them  all ;  the  other  teeth  were  all  still  "alive  ". 
The  pivoting  had  been  beautifully  done  in  the 
early  manner ;    septic    trouble   had  not  super- 
vened ;    hence    the    pulplessness  had    been    no 
detriment  to  the  tooth,  but  apparently  a  benefit. 


ROOTS    SUITABLE   FOR   CROWNS 

General. — Any  root  that  is  sufficiently  acces- 
sible, that  offers  a  good  proportion  of  sound 
dentine,  and  is  tight  enough  to  stand  the 
strain  of  mastication,  can  be  crowned ;  but 
seeing  that  the  root  is  to  afford  the  sole  support 
for  the  crown,  it  is  obvious  that  the  sounder, 
the  larger,  the  longer,  and  the  tighter  the  root, 
the  better  chance  is  there  of  the  result  being, 
so  far  as  such  a  term  is  applicable  to  a  portion 
of  the  human  frame,  permanent. 

Determination  of  the  Desirability  of  Crowning 
any  Particular  Root. — In  making  an  estimation 
of  the  desirability  of  crowning  a  given  root,  the 
following  points  are  to  be  considered. 

(1)  Tlie  soundness  of  the  root — its  fixity,  its 

length,  its  freedom  from  caries. 

(2)  The  probable  length  of  life  when  crowned. 

(3)  The  value  in  function  and  appearance  to 

the  patient  of  the  prospective  crown. 

In  estimating  the  amount  of  sound  dentine 
present  in  a  root,  it  must  be  recognized  that  if 
the  pulp  is  alive,  the  root  is  almost  sure  to  be 
"good  for  crowning  ".  A  root  that  has  been 
neglected,  and  whose  pulp  has  been  dead,  with 
the  root-canal  open  to  the  mouth  for  a  long 
time,  may  be  so  extensively  softened  from 
within,  through  the  canal  being  filled  with 
debris  of  food  and  micro-organisms,  that  it 
will  be  unfit  for  crowning.  Moreover,  the 
chronically  septic  condition  may  have  caused 
absorption  of  the  tip  of  the  root  by  an  inflarned 
periodontal  membrane.  The  presence  of  a  live 
pulp  is,  therefore,  a  favourable  feature  because 
it  denotes  the  soundness  of  the  dentine  with 
which  it  is  in  organic  connection,  and  the 
preservation  of  the  root  from  the  attacks  of 
micro-organisms  and  their  resultant  acids.  In 
this  case  the  pulp  of  course  wiU  have  to  be 
extirpated  preparatory  to  crovraing. 

The  degree  of  fixity  of  the  root,  if  doubtful, 
must  be  tested  by  moderate  attempts  to  shake 
it. 

Its  length  can  be  tested  by  probing  the  canal 
with  a  Donaldson  bristle  and  feeling  for  the 
end.  Tliis  process  may  indicate  that  the  root 
is  too  short  for  crowning,  even  though  the 
dentine  is  hard  and  comparatively  free  from 
caries.  The  root  may  have  lost  much  of  its 
length,  not  only  by  caries  at  the  surface,  but 
by  absorption  at  the  apex.  When  the  canal 
is"  felt  to  te  enlarged  at  the  apex  by  absorption, 
the  actual  length  can  be  measured  by  passing 
up  to  the  apex  a  hooked  Donaldson  bristle. 
This  hook  can  be  hitched  over  the  end  of  the 
root  and  the  length  indicated  on  the  bristle 
by  sliding  to  the  mouth  of  the  canal  a  small 
washer  of  rubber-dam  through  which  the  bristle 


540 


lias  been  previously  passed  (see  Fig.  619).  On 
removang  the  bristle  from  the  root  the  length 
will  be  denoted  by  the  distance  of  the  washer 
from  the  hook. 

The  depth  of  caries  on  the  surface  and  in  the 
interior  must  be  judged  by  fairly  hard  pressure 
with  the  point  of  a  sharp  stiff  steel  explorer. 
If  the  amount  of  softening  is  still  in  doubt,  the 
question  must  be  settled  by  removing  all  the 
carious  portion  with  a  sharp  round  burr. 

The  probable  "  length  of  life  "  when  crowned 
will  be  estimated  largely  on  the  result  of  the 
examination  as  above,  but  sometimes 
a  very  poor  root  will  repay  crowiiing 
when  the  advantage  to  the  patient  of 
Rubber  havuig  the  crown  would  be  great,  even 
washer  though  the  "  expectation  of  life  "  be 
but  a  few  years. 

On  the  other  hand,  many  a  doubtful 
root,  when  crowned,  will  last  mucli 
longer  than  might  have  been  ex- 
pected ;  and  a  previously  neglected 
root  will  often  actually  tighten  some- 
what in  its  socket  after  bemg  crowned. 
This  improvement  probably  ensues 
partly  by  reason  of  the  thoroughness 
with  which  the  root  is  rendered  and 
kept  aseptic  by  the  processes  attend- 
ant upon  crowning,  and  also  partly 
by  reason  of  the  root  being  restored 
to  function. 

The  amount  of  fixity  of  a  root  that 
will  enable  it  to  withstand  the  force  of 
the  bite  will  depend  largely  upon  the 
nature  of  the  bite ;  for  instance,  a 
root  that  could  not  stand  the  impact 
of  a  bite  when  powerfully  delivered 
by  strong  natural  teeth  of  a  vigorous 
person,  would,  perhaps,  be  quite  equal 
to  the  strain  when  the  bite  is  delivered 
by  artificial  teeth  on  a  plate,  or  in  the 
Fig.  019.     case  of  a  less  vigorous  person. 

The  value  of  crowning  is  especially 
evident  when  it  saves  the  patient  from  the  wear- 
ing of  a  plate.  A  tooth  ideally  crowned  is  not 
only  the  acme  of  comfort  and  efficiency,  but  is  as 
mnocuous  to  the  remaining  teeth  as  the  natural 
tooth  itself.  On  the  other  hand,  a  plate  must 
always  lack  such  a  full  measure  of  comfort  and 
efficiency ;  must  also  always  be  a  source  of  some 
trouble  and  solicitude  to  the  patient,  and  in  a 
great  number  of  cases  will  ultimately  damage 
the  adjacent  natural  teeth.  The  amount  of  dis- 
comfort occasioned  by  wearing  a  plate  is  a  very 
variable  quantity  in  different  cases,  and  while 
some  patients  will  assert  that  in  actual  wear 
their  plates  occasion  them  no  discomfort,  it  is 
certainly  true  that  other  patients  never  get 
reconciled  to  the  feeling  of  having  a  plate  in 
the  mouth,  and  are  incurably  afflicted  by  dis- 
comfort thereby.     The  writer  substituted  two 


central  incisor  crowns  for  a  gold  plate  that  had 
been  fitted  over  the  roots  of  these  two  teeth 
and  adjacent  gum  for  a  friend  of  his  who  is 
a  medical  man.  The  plate  was  rather  small, 
and  well  made,  and  fitted  well,  and  had  been 
worn  for  many  years.  Yet  the  patient's  grati- 
tude for  being  relieved  of  it  was  quite  touching, 
and  he  declares  that  the  enhancement  of  his 
comfort  is  enormous.  Without  scrupulous  at- 
tention and  unremitting  cleanliness  on  the  part 
of  the  patient,  a  plate  is  certam  to  do  damage 
to  adjacent  teeth ;  and  even  with  the  greatest 
care  damage  often  ensues,  not  only  by  caries, 
but  by  recession  of  the  gum  caused  by  the 
pressure  of  the  plate.  The  pressure  increases 
the  recession  that  naturally  follows  the  mere 
extraction  of  the  teeth. 

PRINCIPLES    OF   CROWNING 

General. — Crowns  should  be  endowed,  if 
possible,  with  an  excess  of  strength,  both  in 
themselves  and  in  their  attachment  to  the  root ; 
so  that  they  may  defy  not  only  ordinary  strains 
of  mastication,  which  are  m  cumulative  effect 
destructive  enough,  but  also  unexpected  shocks 
and  casualties. 

Provision  should  be  made  to  prevent  rotation 
of  the  crown  upon  the  root. 

The  root-face  should  be  shaped  so  that  the 
crown  can  be  conveniently  fitted  to  it. 

The  cro\vn  should  be  so  fitted  that  it  rests 
fairly  and  squarely  on  the  root. 

Provision  should  be  made  to  prevent  the 
crown  from  bemg  forced  out  of  place  upon  the 
root  hy  the  bite.  In  the  case  of  the  upper  front 
teeth,  the  bite  being  delivered  in  an  outward 


Fig.  620. — Central  "  pivot  "  tooth  with  "  pin-wire  " 
post.  Pin  bent  by  force  of  bite,  and  crown  thrown 
out  of  position. 

direction  as  well  as  upwards,  this  condition  is 
met  by  providing  a  cap  or  half -cap  to  the  neck, 
or  by  merely  usmg  a  sufficiently  thick  and  un- 
bendable  post.  Vast  numbers  of  failures  of 
anterior  crowns  are  due  to  the  tyraimy  of  an 
old  idea,  viz.  that  pin-size  wire  is  the  proper 
wire  of  which  to  make  posts  (see  Fig.  620). 
The  wire  should,  as  a  matter  of  fact,  be  much 
thicker.  In  the  case  of  upper  premolars  the 
condition  is  met,  in  addition,  by  providing  a 
naturally  shaped  two-cusped  masticatory  sur- 
face.    If   the    inner   cusp   is    not    represented. 


541 


but  the  tooth  finished  iii  shape  like  a  canine, 
the  bite  will  very  probably  in  time  shift  the 
tooth  outwards  either  upon  the  root,  or  root 
and  all,  on  account  of  the  bite  being  always 
delivered  on  an  unopposed  inclined  plane. 
The  occlusal  surface  therefore  of  the  crown 
should  be  a  close  copy  of  the  normal.  This 
will  be  referred  to  again  under  the  head  of 
"  Occlusion". 

Where  a  crown  is  fixed  for  a  young  person 
whose  teeth  are  still  lengthening,  it  is  important 
to  be  able  to  remove  the  crown  easily,  as  in  the 
course  of  time  it  will  be  necessary  to  remove  it 
to  cut  down  the  root,  which  will  have  elongated 
and  become  visible  and  unsightly,  and  to  refix 
the  crown,  or  make  another.  In  these  cases 
the  crown  can  be  made  easily  removable  by 
fixing  it  with  gutta-percha  instead  of  cement. 
Then,  on  warming  the  crown,  it  can  be  with- 
drawn from  the  root  without  injuring  either 
the  root  or  the  crown. 


Fig.  621. 

A.  Properly  backed.     Backing  thick  and  extending  to 

edge  of  porcelain.     Edge  of  porcelain  ground  thin 
and  repohshed. 

B.  Improperly    backed.     Flat    tooth,    and    porcelain 

improperly  left  thick  on  incisal  edge. 

In  the  great  majority  of  cases  crowned  teeth 
are  dead  teeth,  i.  e.  the  crowns  will  have  been 
fixed  on  pulpless  roots,  and  when  a  root  pre- 
sents itself  for  crowning  containing  a  live  pulp, 
it  is  nearly  always  best  to  kill  and  remove  the 
■pulp.  When  in  douht,  kill — is  a  useful  working 
rule  wherever  pulps  are  concerned. 

Provision  against  Fracture  of  the  Porcelain. 
Wliere  it  is  desirable  to  fi.x  a  porcelain  or 
porcelain -faced  crown  with  cement,  but  the 
likelihood  of  subsequent  fracture  of  the  porce- 
lain by  the  bite  or  other  causes  of  stress  is 
recognized,  the  porcelain  part  should  be  made 
removable  and  replaceable  independently  of  the 
metal  part,  so  that  the  porcelain  may  be  easUy 
replaceable  m  the  mouth  without  interfering 
with  the  essential  part  of  the  crown.  This  is 
in  the  interest  of  the  root  itself,  and  also  saves 
trouble  should  fracture  occur.  (For  detaOs  of 
removable  facings  see  pp.  590-5.) 

Sometimes,  but  rarely,  teeth  containing  live 
pulps  are  crowned,  and  then  the  metal  post 


has  to  be  dispensed  with,  and  the  whole  attach- 
ment effected  by  a  closely  fittmg  cap  plus  the 
cementing  medium. 

Very  often  the  dowel  or  post  forms  part  and 
parcel  of  the  finished  crown,  and  the  whole 
is  inserted  and  fixed  together;  but  in  the  case 
of  molars  with  divergent  roots,  and  of  certain 
very  carious  single  roots,  or  under  certain 
difficult  circumstances,  or  where  it  is  desired 
to  screw  the  post  into  the  roots,  the  post  or 
posts  are  fixed  first  and  allowed  to  project,  and 


U-J 


A  B 

Fig.  622. 

A.  Section  of  first  upper  premolar  crown  with  collar. 

B.  Same  without  collar. 

the  crown  is  subsequently  attached.  As  a  rule 
the  post  is  not  screw-cut  but  is  merely  forced 
in,  luted  with  cement.  The  subsequent  fixuig 
of  the  crown  to  the  post  is  sometimes  effected 
by  a  screw-nut,  but  generally  by  cement  only, 
or  by  cement  and  amalgam  in  the  combination 
known  as  "  PcA  ". 

The  crown  should  foUow  as  nearly  as  possible 
the  normal  original  contour  of  the  tooth.  It 
must  not  project  beyond  the  edges  of  the  root, 
but  be  finished  absolutely  flush  with  it,  excepting 


Fig.  623. — Improperly  constructed  crowns  projecting 
beyond  edges  of  roots,  affording  a  lodgement  for 
food,  etc. 

the  very  slight  projection  m  the  case  of  cap- 
crowns,  which  is  caused  by  the  edge  of  a  closely 
fitting  collar.  In  this  case  the  edges  of  the 
cap  should  be  bevelled  and  the  projection 
reduced  to  the  smallest  possible  amount  (see 
Figs.  622  and  623).  The  crown  should  be  large 
enough  to  cover  the  whole  root-face  so  that 
none  of  the  root-face  will  remam  exposed. 

Wliere  no  cap  is  used,  care  must  be  taken 
not  to  allow  any  portion  of  the  crown  to  project 
beyond     the    edges    of     the    root-face,    either 


542 


labially  or  lingually.  No  gratuitous  nidus  for 
the  lodgement  of  micro-organisms  or  debris 
of  food  can  be  allowed. 

Hygienic  Considerations. — Any  roughness  or 
projecting  ledges  or  faultily  shaped  interstitial 
surfaces,  which  tend  to  cause  retention  of  food 
between  tlie  teeth  and  the  harbourmg  of  micro- 
organisms, and  any  undue  encroachment  upon 
the  gum,  must  be  avoided.  This  is  true  univer- 
sally and  applies  to  fillings  just  as  much  as  to 
crowns.  If  a  nidus  is  formed  for  the  lodgement 
of    decomposing    food    and    septic    organisms 


Fig.  624. — Sections  of  properly  constructed  crowns 
showing  ends  of  roots  "  coned  "  and  caps  fitted 
close  with  no  projecting  edges. 

much  mischief  may  ensue ;  for  local  irritation 
will  be  set  up,  which  may  not  stop  at  a  mere 
local  gingivitis,  but  may  cause  more  or  less 
periodontitis  and  even  osteitis  of  the  alveolar 
bone — inflammations  that  manifest  themselves 
in  tenderness  of  the  tooth  on  pressure  and 
gradual  loss  of  attacliment.  The  systemic 
mischief  that  may  result  from  absorption  of 
the  noxious  products  of  micro-organisms,  and 
from  swallowing  these  poisons  and  the  germs 
themselves,  may  become  the  graver  side  of  the 
question  ;  and  to  escape  condemnation  on  these 
two  counts,  crowns  must  be  constructed  so  as 
to  present  no  salient  projections  or  encroach- 
ments upon  the  gum,  and  the  greatest  care 
must  be  exercised  to  get  a  very  accurate  fit  at 
the  junction  of  crown  and  root,  particularly  if  a 
collar  or  cap  on  the  root-end  is  used.  \\'hen 
a  collar  is  to  be  used,  it  must  not  be  forced  into 
the  soft  tissues,  but  must  be  fitted  only  to  parts 
of  the  tooth  that  can  be  see7i  or  felt.  The  edge 
of  the  root  or  cervix  of  the  tooth,  or  any  other 
part  of  the  tooth  that  is  to  be  grasped  by  the 
hand,  must  be  so  shaped  as  to  have  parallel 
sides,  or  sides  slightly  coned,  so  that  it  is  as 
easy  as  possible  to  secure  a  very  close  adaptation 
of  collar  to  tooth  (see  Fig.  624).  Wlien  crowns 
are  fitted  and  made  as  perfectly  as  possible, 
wliether  they  have  collars  or  no,  they  are 
quite  free  from  objection  as  regards  their 
effect  on  the  hygiene  of  the  mouth ;  in  fact, 
owing  to  their  optional  contour  and  their 
smooth  indestructible  surfaces,  they  are  dis- 
tinctly superior  in  this  very  respect  to  the 
patched-up  apologies  for  natural  crowns  that 


they  generally  supersede.  Let  it  be,  there- 
fore, the  ambition  of  the  operator  to  produce 
crowns  that  shall  not  only  be  useful,  durable, 
and  artistic  organs,  but  shall  be  also  free  from 
the  important  objection  of  insanitary  encroach- 
ments upon  the  inter-dental  spaces,  gum,  and 
periosteum.  Previous  writers  on  crowning, 
when  describing  collars,  have  erred  in  recom- 
mending and  figuring  collars  far  too  deep,  and  in 
allowing  that  collars  may  to  some  extent  be 
forced  into  the  soft  tissues.  Collars  should 
never  be  so  deep  as  to  injure  the  soft  tissues  or 
cause  pain. 

The  Use  of  Collars  and  Caps. — The  advantages 
of  collars  and  caps  tightly  fitting  the  root-end, 
when  that  root -end  presents  a  strong  edge, 
are — 

(1)  They  very  greatly  add  to  the  strength  and 

stability  of  the  crown. 

(2)  By  covermg  up  the  joint  they  protect  the 

sectioned  edge  of  cementum  and  dentine 
from  the  deleterious  action  of  acids 
and  caries-producing  organisms. 

(3)  They  greatly  reduce  the  liability  of  a  root 

to  split  under  the  strains  of  mastication 
or  accidental  violence. 

These  advantages  take  effect  to  the  full  when 
the  root  is  strong-edged  and  sufficiently  acces- 
sible for  a  projjer  accuracy  of  fit  to  be  obtained, 
but  vanish  pari  pa^sii  with  the  reversal  of  these 
conditions.  Therefore,  it  is  necessary  to  dis- 
tinguish the  occasion  on  which  it  is  and  is  not 
proper  to  apply  a  collar  or  cap  to  the  end  of 
the  root. 

When  Caps  are  Contra-indicated. — (1)  In 
those   cases   where   the   root   is   carious   much 


Fig.  625. — Showing  how  a  collar  may  appear  to  fit 
the  edge  of  the  root  tightly,  and  yet  by  being 
forced  too  deeply  may  have  a  projecting  edge 
under  the  gum.     (J.  H.  Badcock.) 

under  the  gum,  and  the  soft  tissue  is  adherent 
to  its  edge,  a  cap  is  not  admissible.  To  place 
a  collar  here  would  mean  cutting  away  a 
considerable  part  of  the  attachment  of  the 
periodontal  membrane  to  the  root,  and  owing 
to  the  more  or  less  buried  position  of  the  root, 
it  would  be  an  unpractical  proposition  to  shape 
the  sides  of  the  root  properly  to  parallelism 
or  conical  form,  without  which  the  collar  would 
probably  not  fit  well  enough  to  justify  its 
existence. 

It  must  be  remembered  that  under  the  gum 


643 


most  roots  are  curved  by  Nature  in  the  direction 
opposite  to  what  is  required  for  tlie  fitting  of 
a  collar,  and  a  collar  forced  on  in  such  a  position 
will  have  its  edge  standing  widely  away  from 
the  root  (see  Fig.  625). 

(2)  In  those  cases  where  the  root  is  hollowed 
out  into  crater-like  form,  leaving  very  thin 
edges  it  is  not  to  be  expected  that  a  collar 
encircling  those  edges  will  add  much  to  the 
holding-power  of  the  crown,  nor  will  it  add 
appreciably  to  the  resistance  to  splittmg  of 
the  root. 

It  «ill  be  seen  then,  that  the  contra-indica- 
tions  to  a  collar  are  all  centred  in  the  mechani- 
cal difficulties  that  sometimes  accrue  from  an 
advanced  state  of  caries  of  the  root,  which 
precludes  the  possibility  of  properly  fitting  the 
collar  without  damaging  its  attachment  to  the 
soft  tissues. 

The  question  of  appearance  also  arises,  but 
is  not  fundamental,  because  when  the  appear- 
ance of  a  collar  on  the  external  part 
of  a  tooth  would  be  objectionable,  the 
collar  can  always,  with  a  little  extra 
trouble,  be  nearly  or  quite  covered  by 
the  porcelain  portion  of  the  crown 
(see  Fig.  626). 

Shape  and  Depth  of  Collars. — When 
the  gingival  margin  is  irregular, 
festooned,  or  higher  at  one  part  than 
Fig.  026.  another,  the  band  or  collar  of  a  crown 
must  have  its  edge  shaped  accord- 
ingly, or  else  corresponding  to  the  attachment 
of  the  periodontal  membrane,  which  is  generally 
much  the  same  thing.  This  means  that  the  band 
is  not  to  be  fitted  by  crudely  jamming  it  on, 
so  as  to  detach  portions  of  the  membrane  from 
the  root.  The  band  must  be  so  festooned  as 
to  follow  the  attachment,  if  necessary,  of  this 


A  B 

Fio.  627. 

A.  Shell   crown   "  festooned  "   to  follow   the  edge   of 

the  gum. 

B.  Shell  crown  improperly  forced  under  gum  at  back, 

owing  to  absence  of  proper  "  festooning". 

delicate  and  sensitive  membrane  without  de- 
taching it  at  all  (see  Fig.  627).  If  any  slight 
detachment  from  root  is  desired,  it  must  be 
done  with  a  tiny  knife  and  not  by  the  collar 
itself.  The  tendency  of  crown  workers  who 
use  caps  is  to  use  them  of  too  great  depth,  and 
writers  giving  instructions  upon  making  cap 
crowns  are  at  fault  m  recommending  this.     A 


cap  of  a  porcelam  crown  on  an  incisor  or  pre- 
molar should  hardly  ever  be  more  than  ^^  of 
an  inch  m  depth,  and  very  often  not  more 
than  ^V  of  an  inch,  when  the  edge  of  the  root 
is  level  with  or  slightly  under  the  gum.  In 
such  a  case  the  object  is  to  place  the  collar 
under  the  free  edge  of  the  gum,  and  that  only. 

In  Defence  of  the  Collar. — When  either  free 
from  the  gum  or  placed  under  the  naturally 
free  edge  of  the  gum,  fitted  quite  close  to  the 
root,  bevelled  at  the  expen.se  of  the  outer  sur- 
face, and  properly  luted  with  cement,  no 
objection  can  be  reasonably  urged  against  the 
collar.  It  produces  no  kind  of  irritation,  and 
can  be  kept  clean  in  the  dental  sense.  It  is 
scarcely  more  prominent  than  the  cingulum 
of  natural  enamel  in  the  same  situation.  It  is 
by  no  means  comparable  to  a  layer  of  tartar. 
Tartar  is  an  offensive  accretion  containuig  a 
large  proportion  of  animal  matter,  is  absorbent, 
rough,  and  eminently  prone  to  harbour  micro- 
organisms, and,  most  serious  of  all,  creeps 
deeper  and  deeper  along  the  root,  causing  dis- 
appearance of  the  tooth-socket  and  often 
pyorrhoea.  The  collar  should  be  m  all  these 
respects  the  antithesis  of  calculus.  As  age 
advances  an  apparent  lengthening  of  all  teeth 
ensues  by  gradual  recession  of  gum  and  socket. 
Apart,  therefore,  from  all  question  of  irritation, 
the  most  properly  fitted  collar,  if  it  lasts  long 
enough,  will  in  time  be  found  free,  if  not  origin- 
ally so,  from  the  gum ;  but  this  inevitable  result 
of  the  flyiug  years  must  not  be  confounded  with 
what  it  is  not,  and  ascribed  to  the  maleficent 
efl^ect  of  the  harmless  and  often  necessary 
collar. 

Occlusion. — The  occlusion  of  the  bite  must 
be  specially  studied.  The  finished  crown  should 
receive  just  its  normal  amomit  of  the  bitmg  force 
— neither  more  nor  less.  If  more,  the  crowiied 
tooth  or  the  opposing  one  or  both,  will  be  in 
danger  of  becoming  tender  in  the  socket  by  the 
setting  up  of  periodontitis.  If  less,  the  crowned 
tooth  or  the  opposing  one  will  tend  to  become, 
in  time,  partially  extruded  from  its  socket,  and 
its  roots  thereby  partially  exposed.  A  normal 
firm  bite  keeps  the  teeth  in  place  in  their 
sockets,  but  a  shirking  bite  tends  to  cause  the 
teeth  apparently  to  lengthen — "  feeling  for  the 
bite  ".  The  lengthening,  however,  is  not  real, 
and  merely  represents  a  partial  exti-usion  of 
the  teeth  from  their  sockets  and  a  loss  to  that 
extent  of  their  stability.  The  shape  of  the 
masticating  surface  of  a  crown  should  be  as 
nearly  as  possible  a  reproduction  of  the  normal, 
so  that  the  bite  shall  strike  it  naturally,  and 
not  tend  in  time  to  shift  the  root  into  a  vicious 
position.  For  instance,  in  an  upper  premolar 
the  inner  cusp  should  be  faithfully  reproduced 
and  not  finished  off  like  a  canine ;  otherwise, 
the  impact  of  the  bite  upon  it  wUl  be  received 


544 


by  a  simple  inclined  plane  unopposed,  which 
will  tend  in  time  to  shift  the  tooth  outwards. 
The  presence  of  a  proper  inner  cusp  will  neu- 
tralize this  tendency  by  presenting  an  inclined 
plane  in  the  opposite  direction  (see  Fig.  628). 
Properly  formed  cusps,  also,  made  after  Nature's 


\ 


A  B 

Fig.   628. 

A.  Shows    correct    antagonism    of    upper    and    lower 

premolar. 

B.  Shows  faulty  antagonism  of  upper  and  lower  pre- 

molar owing  to  absence  of  inner  cusp  of  upper 
premolar,  causing  upper  premolar  to  be  gradually 
pushed  outwards  in  direction  of  arrow. 

pattern,  give  the  bite  in  its  various  positions 
that  continuous  antagonism  so  admirably 
arranged  by  Nature. 

Crowns  for  Teeth  not  Exposed  to  View. 
Crowns  for  back  teeth,  which  are  not  ordinarily 
exposed  to  view  even  during  speaking,  laueh- 
ing,  etc.,  are  generally  made  entirely  of  metal 
for  the  sake  of  simplicity  and  strength ;  but 
where  exposed  to  view  they  should  be  either 
made  of  porcelain  chiefly  or  of  metal  porcelain- 
faced. 

The  commonest  form  of  crown  for  molars  is 
the  all-metal  "cap"  or  "shell"  crown.  This 
is  a  hollow  shell  of  gold  or  platinum  or  other 
suitable  metal  made  in  the  form  of  a  molar 
tooth  and  filled  with  cement  and  puslied  on  to 
the  root,  so  enclosing  the  remains  of  the  natural 
crown  and  any  iiUmgs  that  it  may  contain. 
Additional  aid  to  its  fixity  may  or  may  not 
be  provided  in  the  form  of  metal  posts  set  in 
the  roots.  These  are  fixed  in  the  roots  previ- 
ously and  allowed  to  project,  the  projecting 
ends  being  enclosed  in  the  cement  within  the 
crown.  This  crown  in  its  simplest  form  without 
posts  is  suitable  where  the  remams  of  the 
natural  crown  are  sufficient  with  the  aid  of  the 
cement  to  hold  the  crown  securely.  Wliere 
the  natural  crown  is  very  much  hollowed  or 
very  deficient  on  one  side,  or  reduced  nearly  to 
the  level  of  the  gum,  a  post  or  posts  should  be 
fixed,  as  otherwise  under  the  strain  of  mastica- 


tion the  crown  will  probably  either  come  off 
simply,  or  will  come  off  with  the  remains  of 
the  natural  crown  embedded  in  it  (see  Fig.  629). 
The  edges  of  the  crown  should  extend  as  a  nile 
sufficiently  deeply  to  include  all  the  visible  por- 
tion of  the  tooth  and  also  slightly  under  the  free 
edge  of  the  gum,  but  on  no  account  should  the 
soft  tissues  be  damaged  by  forcing  the  edges  into 
the  periodontal  membrane.  The  edges  of  the 
crown  should  fit  absolutely  closely  to  the  root 
all  round,  and  be  bevelled  off  at  the  expense  of 
the  outer  surface,  so  that  no  abrupt  margin  is 
left.  The  crowned  tooth  when  finished  should 
present  as  nearly  as  jjossible  the  appearance  of 
a  natural  tooth  of  which  the  crown  has  been 
gilded.  These  crowns  are  often  made  of 
platinum  instead  of  gold,  when  the  less  ob- 
trusive colour  of  the  platinum  is  preferred. 

The  gold  or  j)latinum  sliell  crown  is  equally 
applicable  for  premolars  whenever  it  happens, 
owing  to  the  conformation  of  the  mouth,  that 
they  are  sufficiently  out  of  siglit. 

Crowns  for  Teeth  Exposed  to  View. — Teeth 
that  are  exposed  to  view  are  treated  by  an 
entirely  different  method  for  the  sake  of  appear- 
ance. The  portion  exposed  to  view,  or  the 
whole  crowii,  is  then  made  of  porcelain,  and  a 
metal  intermediate  portion  is  made  to  attach 
the  porcelain  to  the  root. 

In  the  case  of  upper  premolars  it  is  ordinarily 
the  outer  face  (labial  face)  alone  that  shows,  and 
this  is  the  only  part  that  must  of  necessity 


A  B 

Fio.  629. 

A.  Shows     section     of     molar     with     lingual     portion 

missing.     Here  a  post  fixed  in  the  palatine  root  is 
imperative. 

B.  Same  with  post  fixed  in  palatine  root. 

be  constructed  of  porcelain ;  but  in  the  case  of 
lower  premolars  it  is  the  top  or  masticating 
surface  that  often  shows  the  most,  and  there- 
fore in  such  cases  it  is  very  desirable  that  the 
top  should  be  made  of  porcelain  also. 

A  porcelam  or  porcelain-faced  crown  is  indi- 
cated in  the  majority  of  premolar  crowns,  and 
in  some  cases  also  of  first  molars,  both  upper 
and  lower. 

In  the  case  of  the  six  front  teeth  porce- 
lain or  porcelain-faced  crowns  are  almost 
universally  required.  They  are  attached  to 
the  root  by  one  metal  post  or  dowel,  and  may 
or  may  not  be  provided  with  a  closely  fitting 


545 


bell  shaped  in  section.  In  the  anterior  roots 
of  lower  molars  this  is  so  marked  as  frequently 
to  amount  to  there  being  two  canals,  circular 


Fig.  631. — Section  of  lower  molar  showing  canal  in 
anterior  root  taking  a  course  downwards  and 
forwards  where  it  starts  from  the  pulp-chamber. 

in  section,  the  "  handle  "  of  the  "  dumb-bell  " 
being  obliterated.  The  canals  of  this  anterior 
root  present  an  exception  to  the  rule  that  the 


shallow   cap    to    cover  the    end    of   the    root. 

These  cro\vns  should  in  colour,  size,  shape  and 

position,  be  hfelike  in  appearance,  so  that  arti- 
ficiality is  incapable  of  detection  under  ordinary 

observation. 

Certain   Points  in   the   Anatomy   of  the   Roots 

of  Teeth. — As  the  roots  of  the  teeth  form  the 

princi2)al   and   often   the    only   attachment   of 

cro-ivns,  it  is  important  to  understand  thoroughly 

then-  usual  arrangement  and  shape,  and  also  the 

position,  shajje,  and  direction  of  their  canals. 
The  canal  in  every  root  is  situated  centrally, 

i.  e.  axially  in  the  longitudinal  direction,  and 

of  course  follows  any  curvature  the  root  may 

take.     In  all  the  incisor  and  canine  teeth   the 

canal  is  coincident  with  a  line  drawn  from  the 

centre  of  the  incisal  edge  (or  cusp)  to  the  tip 

of  the  root.  In  lower  pre- 
molars the  canal  is  coincident 

with  a  line  drawn  from  the 

tip  of  the  external   cusp  to 

the  tiji  of  the  root. 

Shape  of  Canals  in  Section. 

The  canals  of  the  six  upper 

front  teeth  m  section  are  for 

all  practical  purposes  circular; 

as  also  are  those  of  each  root 

of  the  two -rooted  first  upper 

premolars.  Tlie  vast  majority 

of    second    upper    premolars 

are  single-rooted,  and  have  a 

single  canal,  but  the  possi- 
bility of  encountermg  ab- 
normalities  must  always  be 

borne  in  mind.  As  an  example 

of  two  separate  canals  in  each 

second  upper  premolar  occur- 
ring    as     an     abnormality, 

observe  the  photograph  (Fig. 

630).  The  canal  of  the  single- 
rooted  second  upper  jjremolar 

is  oval.    Those  of  the  three-rooted  upper  molars  i   canals  follow  the  general  direction  of  the  roots, 

are  chcular.  m  that  while  the  general  direction  of  the  root. 

The  canals  of  the  loioer  incisors,  canines,  and  '  like  most  lower  molar  roots,  is  downwards  and 

backwards,  the  pulp-canal 
when  starting  from  the 
jjulp-chamber  at  first  goes 
dow^lwards  and  forwards, 
then  soon  changes  its  direc- 
tion and  follows  the  direc- 
tion of  the  root  downwards 
and  backwards  (see  Fig. 
631). 

Three-rooted  uj^per 
molars    have    canals    tliat 

Fig.  630.— Foiu-  upper  premolars^  all Jrom  the  same  patient,  sliowing  the  second  deserve    .special    attention, 

owing  to  the  difficulty  often 


Fig.  632. — Simple  cervical  sections  of  all  the  upper  permanent  teetli. 


as  well  as  the  first  to  be  two-rooted. 


premolars,  are  oval  in  section,  the  long  axes  of 
the  oval  being  in  the  labio-lmgual  dkection. 

Those  of  the  lower  molars,  having  ribbon- 
shaped  pulps,  are  very  fiattened  or  else  dumb- 
18 


experienced  in  discovering  the  buccal  canals, 
or  one  of  them.  Tlie  largest  or  palatine  canal 
is  generally  quite  easy  to  find.  The  buccal 
canals    are    often    very    difficult.      Wlien    this 


546 


is  the  case  tlie  anterior  buccal  will  generally 
be  found  more  anteriorly  and  more  externalhj 
than  was  suspected,  and  the  pulp-cbamber 
should  be  enlarged  with  a  round  burr  antero- 
externally  in  order  to  find  it.  When  the 
posterior  buccal  is  difficult  to  find  it  will 
generally  be  found  by  probing  more  internally 
than   was   suspected,   i.  e.   mucli   nearer  to   an 


Fig.  633. — Simple  cervical  sections  of  all  the  lower  permanent  teeth. 


imaginary  straight  line  drawn  from  the  anterior 
buccal  to  the  palatine  canal  (see  Fig.  63i). 

Danger  of  Perforating  the  Anterior  Wall  of 
an  Upper  Incisor  Root. — When  enlarging  the 
canal  of  a  front  upper  tooth,  especially  the  cen- 
tral upper  incisor,  the  inexperienced  operator 
will  be  almost  certain  to  imagine  the  canal  as 
running  in  a  more  anterior  direction  than 
actually  is  the  case.  Hence,  while  perforation 
of  the   wall   of  the   root  posteriorly   is   almost 


Fio.  634. — Cervical  section  of  first  right  upper  molar 
showing  actual  position  of  canals.  The  dotted 
circle  shows  position  one  would  natiu-ally  expect 
to  find  posterior  buccal  canal. 


rest  till  the  patient's  head  lies  nearly  horizontal 
ujjon  it,  the  face  being  turned  up  nearly  parallel 
to  the  ceilmg.  Take  a  largish  smooth  round 
burr,  look  at  the  tooth  or  root  by  du'ect  vision, 
reflecting  the  light  upon  it  by  a  mouth-mirror 
held  in  the  left  hand.  With  the  burr  make  a 
shallow  depression  where  the  mouth  of  the 
canal  is  supposed  to  be.  This  will  clean  the 
site  and  either  show  up  the 
canal,  or  if  the  canal  is  quite 
obliterated,  will  show  up  the 
dark  spot  of  secondary  dentme 
that  denotes  its  former  site. 
Supposing  the  canal  to  be 
quite  obliterated,  take  a  largish 
spear "ijointed  drill  and  run  it 
on  a  short  way  in  the  estimated 
direction  of  tlie  canal,  re- 
membering that  the  direction 
will  run  more  posteriorly  than 
it  is  natural  to  expect.  Remove 
the  drill.  Reflect  the  light 
from  the  mouth-mirror  quite 
up  this  hole  and  look  at  the 
end  of  it  for  the  dark  spot  of 
secondary  dentine.  Take  a 
smaller  spear  drill ;  place  the 
jjoint  of  it  in  the  dark  spot 
and  driU  a  little  further.  With- 
draw the  di'iU  ;  reflect  the  light 
to  the  top  of  the  hole  and 
again  see  the  position  of  the 
dark  spot.  If  it  is  at  the  end  of  the  hole  all 
is  well.  Proceed  in  this  way,  frequently 
changing  the  di'ill,  usmg  the  smaller  and  the 
larger  alternately,  and  always  keeping  the  dark 
spot  at  the  absolute  end  of  the  hole.  In  this  way 
the  centre  of  the  root  can  be  kept  until  the  hole 


unknown,  perforation  of  the  anterior  wall  is  all 
too  common.  Therefore,  while  followhig  along 
this  canal  with  a  sharp-pointed  drill  it  is  neces- 
sary to  direct  the  point  further  back  and  to  hold 
the  handpiece  of  the  engine  further  forward 
than  would  be  expected  (see  Fig.  635). 

Technique — to  follow  with  a  Sharp-pointed 
Drill  the  almost  {or  quite)  Obliterated  Canal  of 
an  Upper  Incisor. — Raise  tlie  operating  chair 
till  the  patient's  head  is  a  little  above  the 
operator's   when  operating.     Lower  the  head- 


FiG.  635. — Section  of  upper  central  incisor  showing 
direction  (by  dotted  hne)  in  which  there  is  a 
danger  of  perforation. 

is  deep  enough  for  any  purpose  without  en- 
dangering the  root  by  eccentric  drilling  and 
possibly  by  perforation  of  its  wall.  The  im- 
portant points  in  this  j)roceedmg  are  :  the 
position  of  the  head  of  the  patient ;  the  use  of 
direct  vision  by  the  operator ;  the  reflection 
of  the  light  to  the  top  of  the  hole ;  the  keeping 
the  hole  large  enough  with  the  larger  spear- 


547 


pointed  drill  to  allow  the  light  to  reach  the 
terminal  spot. 

Surface  Indications  of  the  Direction  of  a 
Buried  Root. — Where  doubt  exists  as  to  the 
direction  of  a  root  it  is  a  useful  plan  to  palpate 
the  surface  of  the  gum  over  the  root  with  the 
tip  of  the  finger,  gently  rubbuig  the  gum 
laterally.  In  this  way  some  indication,  perhaps 
a  strong  indication,  of  the  position  and  length 
of  the  root  ^\ill  be  given  by  tlie  feeling  of  an 


/       \ 


Fig.  636. — Shows  roots  of  central  incisors 
symmetrically  diverging. 

eminence  on  the  surface,  wliich  corresponds 
to  it  exactly. 

Agahi,  if  one  is  dealmg  ^\dth  a  root  of  which 
the  fellow  tooth  on  the  opposite  side  of  the 
mouth  is  mtact  (and  the  du'ection  of  the  root 
obvious),  a  clue  will  often  be  given  to  the 
direction  of  the  root  in  question,  as  fellow 
teeth  are  generally  placed  symmetrically  in  the 
mouth. 

Again,    when    a    tooth    has    been    extracted 


Fig.  637. — Shows  second  upper  molar  root  tilted 
towards  a  space  made  by  extraction. 

some  years  previously  near  to  a  root  that  it  is 
desired  to  crown,  the  coronal  end  of  the  root 
will  often  have  acquired  a  tilt  towards  the 
space  from  which  its  neighbour  was  extracted, 
and  the  knowledge  of  this  fact,  together  \\ith 
palpation  of  the  gum  over  the  root,  will  often 
give  a  clear  idea  of  its  direction. 

When  the  canal  is  not  cjuite  obliterated,  but  so 
nearly  that  the  finest  Morey  drills  « ill  not  follow 
it,  a  passage  may  be  forced  as  a  rule  by  the  finest 


Beutelroc  drill  (see  Fig.  638),  or  Kerr  drill ;  or  by 
a  straight  Donaldson  \\  ith  the  point  sharpened 
to  a  root-shajie,  used  by  twistmg  between  the 
finger  and  thumb  and  at  the  same  time  forcing 


Fig.  638. — Beutelroo's  root -canal  instruments. 

{Dental  Manufacturing  Co.,  Ltd.) 

upwards.  This  must  be  done  \\ith  a  sensitive 
touch,  and  when  the  Beutelroc,  Kerr,  or  Donald- 
son has  reached  a  short  distance  further  u^j  the 
canal,  it  should  be   followed   to   that  distance 


II 


Fig.  639. — I.  Nomenclature  of  parts  of  root  prepared 
for  crowning  (in  section),  (a)  End  of  root-hole; 
(6)  Root-hole;  (c)  Sides  of  root-end;  (d)  Labio- 
cervical  edge ;  (e)  Linguo-cervical  edge ;  (/)  Mouth 
of  root-hole ;  (g)  Root-end,  root-face,  or  coronal 
end  of  root. 
II.  Root-face. 

by  Morey  cli-Uls,   and  so  on,  till   the  furthest 
pouit  is  reached. 

N.  S.  Jenkins  says  that  to  i^erf orate  a  root 
(meanmg  laterally)  is  a  great  and  inexcusable 
blunder,  and  the  wTiter  agrees  with  him. 


548 


Preparing  a  Root  for  Crowning. — As  in  filling, 
so  in  crowning,  all  carious  dentine  must  be 
removed  from  the  root.  Even  slightly  carious 
dentine  is  always  a  source  of  weakness,  tending 
to  renewed  caries  and  fracture.  In  the  further 
prejjaration  of  the  root  a  guiding  principle 
is  that  as  much  of  the  sound  substance  should 
be  conserved  as  jiossible,  because  the  greater 
the  bulk  of  root-substance,  the  easier  it  is  to 
secure  a  fu'm  attachment  to  it,  and  the  less 
will  be  the  tendency  of  the  root  to  split.  Other 
principles,  however,  conflict  to  some  extent 
with  this,  and  the  extent  to  which  sound 
dentine  should  be  removed  will  be  for  the 
operator  to  decide.     Thus,  (a)  great  obliquity 


Fig.  040. — Nomenclature  of  a  diaphragm  and  pin 
crown  ("  pivot  "  crown)  (in  section),  (a)  "  Tip  " 
of  post;  (b)  Post  or  dowel;  (f)  Diaphragm,  radical 
surface;  (d)  Coronal  end  of  post;  (c)  "  Face  '"  of 
porcelain  facing;  (/)  Pins  of  porcelain  facing; 
(g)  Lingual  contouring;  (/()  Backing;  (J)  "Tip" 
of  porcelain  tooth. 

of  the  root -face  is  an  evil,  and  therefore,  if 
one  side  of  the  root-face  is  deeply  invaded 
by  caries  or  fracture,  it  will  be  necessary  to 
cut  away  the  opposite  side  to  a  considerable 
extent  to  produce  an  apjjroximate  balance  and 
prevent  undue  obliquity  (see  Fig.  642) ;  (6)  to 
produce  an  mvisible  joint  between  crown  and 
root  on  the  labial  aspect  requires  that  the  root 
be  cut  down  till  the  labial  edge  is  overlapped 
by  the  "free"  edge  of  the  gum  (see  Fig.  643) ; 
(c)  where  it  is  required  to  cap  the  end  of  the 
root,  the  part  of  it  that  is  to  be  enclosed 
by  the  cap  must  have  its  sides  demided  of 
projecting  enamel,  and  further  reduced  if 
necessary     to    produce    parallelism    of    those 


sides,  or  even  trimmed  still  further  so  that 
the  root-end  is  slightly  coned  in  a  direction 
opposite  to  the  natural  taj^er  of  the  root ;  {d) 
where  a  porcelain  crowai  is  required,  the  greater 


Fig.  G41. — Nomenclature  of  a  "removable"  porce- 
lain crown  and  of  its  metal  fixing  with  cap  (in 
section),  (o)  Post  or  dowel;  (6)  "Inside"  or 
radical  siu'face  of  cap ;  (c)  Band  of  cap ;  (d)  dia- 
phragm of  cap;  (e)  Coronal  surface  or  "top" 
of  cap;  (/)  Tenon;  (g)  Base  or  radical  surface  of 
crown ;    {h)  Mortise. 


Fig.  642. — Section  of  tooth  (below  dotted  line)  to  be 
removed  to  prevent  great  obliquity  of  root.  If 
a  cap  is  to  be  used  remove  to  b.  If  no  cap  remove 
to  a. 


Lm^uaL. 


Lahial. 


Fig.  643. — Labial  edge  of  root  cut  down  so  as  to  be 
overlapped  by  free  edge  of  gum ;  lingual  edge  not 
so  much. 

the  bulk  of  solid  porcelain,  the  better  is  it 
for  the  strength  of  the  porcelam,  and,  therefore, 
the  root  must  be  cut  do^vii  till  a  sufficiently 
solid  bidk  of  porcelain  is  capable  of  being 
accommodated. 


549 


Principles  Concerned  in  Drilling  the  Dowel- 
hole. — 111  most  crowning  operations  it  is  re- 
quii'ed  to  fix  a  metal  dowel  or  post  into  the 
root  or  roots,  and  in  drilling  the  hole  for  this 
the  following  principles  must  be  kept  in  view — 

(1)  To  foUow  accurately  the  canal  of  the  root 

as  this  is  the  guide  to  its  central  axis. 

(2)  To  reach  almost,  but  not  quite,  to  the  tip 

of  the  root,  or  so  far  as  is  possible  to 
drill  along  the  central  axis  in  a  root 
that  is  curved  or  crooked. 

(3)  To  remove  the  smallest  possible  amount 

of  tooth  substance  compatible  with 
greatest  strength  of  combined  root  and 
dowel.  This  implies  that  the  hole  must 
be  finished  to  a  gentle  taper  correspond- 
ing roughly  to  the  taper  of  the  root 
itself. 

Techyiique  of  Drilling  the  Dowel-hole. — It  is 
assumed  that  the  canal  has  been  j'roperly 
cleansed  and  dismfected.  Proceed  to  estimate 
the  length  of  the  root  by  probing  to  the  end 
if  possible  with  a  smooth  Donaldson  bristle. 
A  small  disc  of  paper  or  rubber-dam  may  be 
impaled  upon  the  bristle  and  the  bristle  pushed 
through  it  into  the  canal,  an  index  of  length 
thus  being  provided  (see  Fig.  619). 

Open  the  mouth  of  the  canal  if  necessary  with 
a  bud-shaped  burr  (see  Fig.  644)  or  with  a 
medium-sized  Morey  drill.  Then  gently  drill 
along  the  canal  with  a  graduated  series  of  Morey 

d 


details  of  procedure  are  all  directed  towards 
ensurmg  proper  clearance  of  the  drills,  and  the 
prevention  of  jammhig,  and  also  the  provision 
of  a  hole  wide  enough  throughout  the  greater 
part  of  its  length  to  facilitate  the  removal  of 
a  broken  portion  should  breakage  of  the  instru- 
ment unfortunately  occur.  Great  care  should 
be  taken  only  to  use  drills  that  are  sharp,  and 
free  from  rust  and  other  blemishes.  (Li 
purchasing  Morey  drills  always  see  that  their 
weakest  part  is  in  the  centre  of  the  flexible  shank 
or  nearer  the  mandrel,  and  not  near  the  "  head  ", 
so  that  in  case  of  fracture  a  sufficient  length  of 
shank  will  be  attached  to  the  head  to  allow  of 


(1 


u 

Fig.  644. — Bakhvin's  Right-angle  Canal  Burr.  For 
funnelling  out  mouths  of  canals.  The  shank  is 
long  to  reach  deep  cavities. 

{Dental  manufacturing  Co.,  Ltd.) 

driUs,  using  a  small  one  as  the  pilot  and  fre- 
quently changing  this  for  a  larger  one,  so  that 
the  canal  is  followed  in  short  stages,  first  by 
the  smallest  drill,  then  by  the  larger  sizes. 
During  the  whole  of  this  drilling  let  the  dental 
engine  be  run  at  a  moderately  high  speed,  but 
let  the  forward  pressure  be  slight  and  sensitive, 
so  that  the  drill  is  allowed  to  cut  its  way  easily, 
and  not  be  jammed  or  broken  by  being  forced 
faster  than  it  is  able  to  go.  Also  let  the  forward 
pressure  be  uitermittent,  alternating  with  a 
slight  withdrawal,  a  sort  of  "touch-and-go" 
action  being  in  fact  used.  Frequently  clear  the 
leaves  of  the  drills  and  clean  them,  so  that  they 
are  not  clogged  ^\ith  their  own  debris.     These 


Fig.   645. — Taper    Drill,   or    Reamer,   for   shaping    the 
hole  to  the  exact  size  or  shape  of  the  post. 

easy  withdrawal.)  Thus  guarded  against,  a 
troublesome  breakage  can  almost  always  be 
avoided. 

After  enlarging  the  canal  with  moderate- 
sized  Moreys  to  as  near  the  tip  of  the  root  as  is 
considered  desirable,  still  further  enlarge  the 
hole  at  its  coronal  end  only  with  a  large  Morey, 
so  as  to  leave  the  hole  with  an  incipient  taper. 
Now  cut  the  whole  length  of  the  hole  to  a 
definite  taper  with  a  special  smooth-sided  reamer 
made  to  the  exact  size  of  the  dowel  that  is  to  be 
used  (see  Fig.  645) .  This  comijletes  the  prepara- 
tion of  the  hole  for  the  dowel.  If  it  is  desued  to 
roughen  the  inside  of  the  hole  for  greater  attach- 
ment of  the  cement,  this  is  better  clone  just  before 
fixing  the  crown.  Standardized  taper  reamers, 
and  taper  dowels  to  fit  the  holes  made  by  the 
reamers,  should  be  kept  in  stock  ready  for  use. 
It  is  important  that  the  posts  should  not  be 
shaky  in  their  holes,  and  should  not  fail  to 
reach  the  end  of  their  holes,  but  should  be 
an  accurate  fit  throughout  their  ivhole  length. 

On  Amputating  the  Crown  of  a  Tooth. — It  is 
necessarj'  to  remove  the  natural  crown,  or 
what  remains  of  it,  by  amputation,  when  a 
porcelain  or  porcelain-faced  crown  is  to  be 
fitted. 

Never  use  "  excising  "  forceps  for  this  pur- 
pose. The  use  of  this  brutal  instrument  tends 
to  cause  pain  and  shock  to  the  patient ;  it  also 
frequently  causes  a  false  line  of  fracture,  and 
is  often  followed  by  traumatic  periodontitis. 


550 


Technique. — Firstly,  cut  through  the  enamel 
on  the  lingual  side  with  a  knife-edge  carbo- 
rundum stone  or  diamond  startmg-point  near 
the  gum  (see  Fig.  646).  Then  take  a  trochar- 
drill,  dead-hard  and  pointed  as  a  three -sided 


5sa*1W 


Fig.   040. — Diamond  Starting  Point. 

(Dental  Manufacturing  Co.,  Ltd.) 

pyramid;  from  the  labial  side,  with  this  drill, 
cut  a  series  of  holes  through  the  enamel  at  the 
cervix  of  the  tooth  along  the  gmgival  margui. 
George  Pedley's  trochar-i^ointed  drill  (see  Fig. 
647)  is  suitable  for  the  purpose,  or  a  drill  serving 


^ 


Fig.  647. — Pedley's  Triangular  or  Trocar  Drills.  The 
form  of  point  prevents  tlie  drill  running  about 
when  commencing  to  bore,  even  on  a  hard  and 
sloping  surface  of  enamel. 

(Messrs.  Claudius  Ash,  Sons  ct  Co.,  Ltd.) 

the  same  end  may  be  readily  extemporized  by 
grinding  the  point  of  an  old  cross-cut  fis.sure-burr 
to  a  three-sided  pjTamid,  and  then  hardening  it 
dead-hard.  Take  a  small  spear-head  ch'iU  (see 
Fig.  648),  and  centreing  it  in  the  holes  through 


Fio.  648.- 


-Spcar-head  Drill,  for  drilling  holes  through 
the  tooth. 


the  enamel,  drill  through  the  tooth  a  series  of 
parallel  tumiels  (see  Fig.  649).  Care  must  be 
taken  to  incline  the  drill,  so  that  the  gum  will 
not  be  injured  when  the  drill  emerges  on  the 
lingual  side,  as  the  gum  is  nearer  the  incisal 
edge  lingually  than  labially  (see  Fig.  650). 


Then  take  a  sharp,  small,  cross-cut  fissure- 
burr  (No.  2  or  3),  run  it  rapidly,  pass  it  into  one 
of  the  holes,  and  with  lateral  pressure  and 
a   sawing    motion    cut   away   the    intervenmg 


Fig.   649. — Broken-down  central  incisor,  showing  series 
of  drill  holes  made  on  labial  side. 

dentine,  and  so  jom  up  the  holes  (see  Fig. 
651).  Wlien  the  crown  is  nearly  detached  by 
these  means,  take  a  stiff  straight  enamel-chLsel, 
and  insert  it  into  the  slot,  and  lever  off  the 
crown.    This  last  should  be  done  only  when  but 


Fig.  650. — Showing  obliquity  of  gum  level,  and 
obliquity  of  drill  necessary  to  avoid  wounding 
gum  on  Ungual  side. 

slight  force  is  required.  In  this  way  all  shock 
is  avoided,  and  the  section  made  to  follow  the 
actual  line  intended. 

The  trimming  of  the  root-face  is  then  pro- 
ceeded with,  and  is  best  done  with  steel  root- 


Fig.   651. — Cross-cut   Fissure-burr   for  joining   up   the 
holes. 

facers  and  carborundum  wheels.  The  best 
root-facers  are  those  of  Raulie  (see  Fig.  652), 
which  have  a  wheel-shape  with  a  fine  Ime  of 
teeth  running  spirally  round  the  working  sur- 
face.    After  the  steel  tool,  the  edges,  especially 


551 


the  labial  edge,  should  be  finished  very  smooth 
with  a  carborundum  wheel,  and  the  gum  must 
not  be  injured  (see  Fig.  653).  The  best  general 
shape  for  the  root-face  is  slightly  domed  or 
obtusely  roof-shaped,  with  tlie  labial  edge  just 
overhung  by  the  "free"  edge  of  the  gum 
(see  Fig.    654).     This  shape  allows  maximum 


Uu 


Fig.   653. — C'arboriindimi  Stump  Wheels. 

(Dental  Manujacturing  Co.,  Ltd.) 

crown  should  always  be  in  mind  in  shaping  the 
root-face.  Great  obliquity  of  root-face  must 
be  guarded  against,  as  a  great  obliquity  gives 
a  less  firm  seat  for  a  crowii  than  one  that  is 
roughly  at  right  angles  to  the  dowel. 


Labi  at  side 


Palatal  side 


Fig.  652. — RaiUie's  Root-facers. 

length  of  dowel,  but  frequently  the  root-face 
wiU  be  found  seriously  encroached  upon  by 
fracture  or  caries,  and  this  will  prevent  an 
ideal  shape  beuig  arrived  at,  and  will  largely 
determine  what  the  resulting  shape  may  be. 
The    prevention    of    rotation    of    the    finished 


surface,  or  surfaces,  of  one  of  them  from  the 
occlusal  surface  to  the  gum,  the  best  way  by 
far  is  by  use  of  the  diamond  disc  in  the  dental 
engine  (see  Fig.  655). 

Technique. — The  liandijiece  hokUng  the  dia- 
mond disc  must  be  held  firmly  in  the  fingers 
as  in  holding  a  pen,  with  the  uidex  finger  and 
the  middle  finger  firmly  supporting  each  other 
behind,  and  the  thumb  in  front.  The  risk 
to  be  guarded  against  is  that  of  the  disc 
running  away  from  its  icork  and  injming 
the  soft  tissues  of  the  mouth.  The  disc 
should  be  wetted  with  a  solution  of  soap 
or  weak  "lysoform",  and  sprinkled  with 
fine  carborundum  powder  to  increase  its 
cutting  power.  The  engine  should  be  run 
moderately  fast,  and  the  disc  allowed  to 
cut  its  way  easily  and  without  hurry  or 
forcing.  A  safe-sided  disc  may  be  used  to 
guard  against  shaving  off  part  of  the  contiguous 
surface  of  the  next  tooth,  and  as  an  extra 
precaution  against  this  an  Ivory's  No.  2  steel- 
band  matrix  can  be  put  around  it.  As  a  pre- 
caution against  wounding  the  tongue,  a  Claude 
Rogers  shield-clamp  may  be  applied  to  the  tooth 
behind  the  one  being  operated  on,  and  the 
"  Toomey-safety-device  "  should  be  used  to 
guard  the  disc. 

In  using  the  diamond  disc  for  cuttmg  away 
the  enamel  of  an  approximal  surface  that  is  in 
contact  with  the  neighbouring  tooth,  there  is 
the  risk  of  the  disc  jamming  momentarily  and 


Fig.' 654. — Shows  root-face  slightly  domed  or  roof- 
shaped  and  cut  down  slightly  under  free  edge  of 
gimi  on  labial  side. 

Cutting  a  Space  between  Contiguous  Teeth. 
Instead  of  entirely  excising  all  that  remains 
of  the  natural  crown,  it  may  be  desired  to 
conserve  as  much  of  it  as  possible  and  to  en- 
close it  within  a  hollow  metal  shell.  This 
particularly  ai^plies  to  molars,  as  will  be  de- 
scribed later  in  dealing  with  the  gold  shell 
crown. 

When  the  teeth  are  in  contact  with  each  other, 
and  it  is  desired  to  cut  down  the  interstitial 


Fig.  655. — Diamond  Discs. 

[Dental  Manufacturing  Co.,  Ltd.) 

then  kicking  away  from  its  work  and  badly 
damaging  the  soft  tissues  of  the  mouth.  Suf- 
ficient practice,  however,  will  soon  give 
confidence  to  the  ojoerator  and  security  to  the 
patient,  enabling  the  hardest  enamel  to  be 
cut  down  between  the  closest  of  teeth  without 
fear  of  accident.  As  the  disc  rapidly  revolves, 
the  operator  should  feel  that  it  is  cutting  its 
way  really  easily  and  freely  and  is  not  behig 
forced ;  a  slight  variation  of  direction  should 
frequently  be  given  to  the  disc  to  ensure  the 
division  being  cut  wider  than  the  thickness  of 
the  disc,  and  the  disc  frequently  \\ithdra\\ai 
altogether  for  dipping  in  the  lubricant  and 
sj>rinkling  with  carborundum  grauis.  Jammmg 
will  thus  be  guarded  against.  In  case  of  a 
jam  being  felt  the  disc  must  at  once  be  slightly 
removed  from  its  work,  and  the  engine  stopped 
at  the  same  instant.     If  the  electric  engine  is 


552 


being  used,  and  the  operator  is  standing,  the 
whole  weight  of  the  operator's  body  must  be 
resting  on  the  foot  that  is  not  operating  the 
switch,  so  that  the  operator  will  be  in  the  most 
advantageous  position  for  immediately  releasing 
the  balance  of  the  switch  without  altering  the 
body.  If  the  operator  is  seated,  the  switch 
must  be  placed  in  such  a  position  on  the  floor 
that  it  can  be  instantly  released  without  dis- 
turbing the  balance  of  the  body. 

Flat  diamond  discs  are  the  most  generally 
useful,  and  next  to  these,  those  forming  a 
flattened  hollow  cone.  Frequent  dipping  of 
the  disc  in  soapy  solution  and  sprinkUng  with 
fine  carborundum  grains  will  be  found  greatly 
to  increase  the  speed  and  facility  with  which 


C  D 

Fig.  656. 

A.  Disc-dowel  for  fixing  gutta-percha  on  end  of  root. 

B.  Tinned  tack  for  same  purpose. 

C.  Disc-dowel  roughly  fitted  to  root  and  padded  with 

gutta-percha. 

D.  Tinned  tack  similarly  padded. 

even  the  diamond  disc  will  do  its  work,  and  this 
is,  if  possible,  more  forcibly  true  for  carborun- 
dum discs.  The  unpractised  hand,  in  order  to 
avoid  accidents,  should  adjust  the  engine-cord 
slack,  so  that  its  degree  of  tension  will  only 
suffice  to  rotate  the  disc  when  workmg  easily 
and  freely,  and  will  cease  to  hold  on  the  slightest 
suspicion  of  a  jam. 

Exposing  a  Buried  Root. — Wlien  a  root  to  be 
crowned  is  buried  under  the  gum  it  must  first 
be  exjjosed  by  prelimmary  treatment,  which 
may  occupy  several  days. 

Technique.  —  After  cleansing  and  disinfect- 
ing the  root-canal  enlarge  it  by  means  of  a 
graduated  series  of  Morey  drills  followed  by 
the  taper  drill  or  reamer.  Then  take  a  tem- 
porary brass  or  German  silver  disc -do  \\  el,  a 
stock  of  which  should  be  made  in  the  workroom 
and  kept  ready  for  use.  Roughly  fit  this  to 
the  supposed  sliape  of  the  root-end  and  length 
of  the  hole.  Apply  a  softened  wad  of  gutta- 
percha to  the  dowel  and  disc,  and  tightly  jam 
it  into  the  canal,  and  so  cause  the  gutta-percha 


to  fit  itself  to  the  root -face  and  press  on  the 
gum  all  round  (see  Fig.  656).  A  tinned  tack 
can  be  used  with  gutta-jaercha  instead  of  the 
disc-dowel,  and  will  generally  require  its  spike 
to  be  reduced  laterally  with  a  file  and  its 
point    blunted.     This    must    be   left   m   for   a 


A  B 

Fig.  657. 

A.  Lateral  perforation  caused  by  parallel-sided  drill. 

B.  Lateral  perforation  avoided  by  using  taper  drill. 

day  or  so,  and  then  removed,  and  the  process 
repeated  if  necessary,  and  perhaps  the  root 
may  be  partially  trimmed  after  each  applica- 
tion, but  the  application  must  be  persisted 
in  vintil  the  root-end  is  clearly  exposed  in  its 
entirety. 


Fig.  658. — (a)  Root  reamed  to  correct  taper ;  (b)  Post 
of  correct  taper  (magnified) ;  (c)  Post  of  incorrect 
taper  and  objectionable  sharpness;  (d)  Post  of  too 
abrupt  a  taper,  affording  little  retention. 

Where  the  root  has  been  exposed  in  this  way, 
the  gum  has  a  great  tendency  to  roll  quickly 
over  the  edges  again  when  the  wad  is  removed ; 
therefore,  until  the  crown  is  fixed,  the  wad 
must  be  refixed  at  the  end  of  each  sitting,  and 
the  patient  never  allowed  to  leave  the  chair 
without  it. 


Fig.  659. — Gauge  made  of  ivory  for  testing  taper  when 
making  posts.  The  test  hole  through  the  laminae 
of  the  gauge  is  drilled  with  the  reamer  that  is  used 
for  the  root. 

Even  after  amputation  of  a  natural  crown 
where  the  root  is  ground  do^v^l  ever  so  slightly 
beyond  the  free  edge  of  the  gum,  it  is  best  to 
fix  a  wad  of  gutta-percha  in  this  way  to  be  worn 
during  the  intervals  between  the  sittings,  so 
great  is  the  tendency  of  the  gum  to  roll  over 
the  edges  of  a  root  when  allowed  any  opportunity 
of  doing  so. 


553 


1 
Fig.  660. 
Taper  Reamer. 


On  Posts  or  Dowels 

0)1  the  Material  of   which  Iknvels  should    be 
made. — It    is    of    great    importance    that    the 
material  used  for  dowels  should 
be     the     strongest     and     sliffest 
that  can  be  obtained.     It  must 
also  be  non-corrosible.    Tlie  best 
materials  at  present   in   use    are 
platinized   gold    and    iridio-plati- 
num.     The   strength  of  German 
silver  and  dental  alloy  is  far  below 
these.     Every  jjost  must  be  fixed 
axially  in  its  own  particular  root 
to  avoid  weakening  and  risk  of 
perforation.     Wlien  a  crown  is  to 
rely  mainly  on  posts  for  its  attach- 
ment every  root  should  have  its 
post  —  single  -  rooted    teeth,    one 
post ;    multi-rooted  teeth,  a  post 
for  each  root. 
CMracter  of  Post  or  Doivels.— The  character 
of  a  post  or  dowel  should  be  such  as  to  afford 
the  strongest  possible  attach- 
ment for  a  crown  consistently 
«ith    the   root    retainuig   its 
maximum  of  strength.     It  is 
useless  to  provide  a  dowel  so 
large  that  the  root  is  greatly 
weakened  for  its  accommoda- 
tion .    What  is  ^^-anted  is  maxi- 
mum   strength    in    combined 
root  and  dowel.     The  strength 
of    the    attachment     of     the 
dowel  to  the  root  largelj^  de- 
pends   upon   its    length ;  and 
the  longer  the  post,  not  only 
the  stronger  will  it  be,  but  the 
less   Hkely  to   split   the   root 
under  strain.    Therefore  posts 
should  be  as  long  as  possible, 
short  of  the  actual  tip  of  the 
root.    Strength  should  be  at  its 
maximum  at  the  part  that  has 
to  bear  the  maximum  strain, 
i.  e.  at  the  coronal  end.     The 
shape  should  be  such  as  will 
necessitate  sacrificing  the  min- 
imum amount  of   tooth  sub- 
stance ;  therefore,  the  bulk  of 
the  post  should  not  be  greater 
at  any  part  tlian  is  necessary 
for  maximum  strength.    No^\■, 
the    strain    that   a   post   will 
and  Wire  Hokler!   "chiefly  be  Called  upon  to  resist 
for  holding  wire   is  a  shearing  strain  caused  by 
while  being  filed   leverage   of   the  crown  upon 
to  a  taper.  ^^j^g  pgg^  under  lateral  strain, 

and  this  leverage   is   exerted 
most   strongly  at  the  end  of 
the    post    nearest    the    crown,    and    least   at 
the  tip.     The  shape  of  post  that  entirely  fulfils 
18  * 


Fig.    OUl. — Uroach 


{Dental     Manufac 
luring  Co.,  Ltd.) 


all  these  requirements  is  a  shape  roughly  corre- 
sponding to  the  root  itself,  i.  e.  a  gentle  taper 
and  a  taper  that  fits  the  hole.  The  hole  that 
is  requu-ed  is  a  taper  hole,  as  this  sacrifices 
the  mhiimum  amount  of  root-substance  and 
runs  the  least  risk  of  perforating  the  root  later- 
ally near  the  apex  (see  Fig. 
657).  A  post  that  fits  its  hole 
will  hold  more  tightly  than 
one  that  does  not,  and  is 
obviously  stronger;  and  for 
these  reasons  j)osts  should  be 
made  accurately  to  fit  the  whole 
length  of  the  taper  hole.  Tlie 
post  must  resist  withdra^^'al, 
when  cemented,  as  strongly 
as  possible ;  therefore  the  taper 
must  be  very  gradual  and  not 
abrupt,  and  the  rough  file-cut 
surface  should  be  left  upon  it. 
The  pomt  should  be  blunt  and 
rounded  and  not  sharply  acute 
(see  Fig.  658) .  The  method  of 
correctly  making  the  tajser  of 
the  posts  LS  by  filing  them  to 
fit  the  gauge  (see  Fig.  659)  in 
which  the  hole  is  made  by  the 
drill  to  be  used  on  the  patient. 
The  taper  post  has,  more- 
over, great  advantages  tech- 
mcally,  as  when  kept  in  stock 
of  standard  taper,  made  to  fit 
the  hole  produced  by  the 
reamer  (also  of  standard  taper) 
(see  Fig.  660),  it  acquires  an 
immediate  and  automatic  fit 
when  inserted  in  either  long 
or  short  holes,  and  its  thick- 
ness  at  the   line  of   greatest 


^ 


Fig.   G62. — Shownig   two   taper  Fig.     663. — Special 

posts    firmly    fixed    together,  Pliers  for  manipu- 

wluch  can  be  inserted  or  with-  lating     posts     or 

drawn  from  their  taper  holes,  dowels, 
though  shghtly  divergent. 

shearing  strain  increases  ua  proportion  to   its 
length.  I 

Consider  the  deskability  of  the  posts  being 
taper  m  the  case  of  a  crown  that  requires  two 
posts  slightly  divergmg  from  one  another.     This 


554 


is  the  condition  that  generally  obtains  in  the 
first  upper  premolar  (one  of  the  crowns  most 
frequently  in  demand).  Here  the  taper  will 
often  allow  the  two  posts,  when  fixed  together, 
to  be  withdrawn  and  reinserted  without  the 
divergence  causmg  them  to  bmd  m  their  holes, 
as  would  necessarily  be  the  case  if  the  posts  were 
cylmdrical  (see  Fig.  662). 


G<i4.      riiic  liiictt's  "  Universal  "'  Micrometer 
Gauge  for  plate  or  wire. 
{Messrs.  C.  J.  Plucknetl  cfc  Co.,  Lid.) 

Thickne.s.s  of  Wire. — The  thickness  of  wire 
from  which  the  taper  posts  are  made  should  be 
several  sizes  larger  than  "  pm  size  ",  when  long 
posts  are  requu'ed.  Vast  numbers  of  dowelled 
cro•w^lS  or  "  pivot  "  teeth  in  the  front  of  the 
mouth  have  failed  simply  through  the  bending 
of  the  pin  in  an  outward  direction  under  the 


A  B 

Fig.  065. 

A.  A  taper  dowel  produces  no  air-lock  and  causes  no 

injurious  pressure  at  the  apical  foramen. 

B.  A  cylindrical  dowel  produces  an  air-lock,  a,  which 

greatly  impedes  the  forcing  home  of  the  dowel  and 
also  causes  great  risk  of  forcing  air  or  cement 
through  the  apical  foramen. 

outward  thrust  of  the  bite.  This  cause  of  failure 
may  generally  be  ascribed  to  the  operator's 
habit  of  using  only  "  pin-size  "  wire.  "  Pin- 
size  "  wire  is  not  thick  enough  for  ordinary 
purposes,  and  when  used  should  be  restricted 
to  small  buccal  roots  of  upper  molars,  lateral 
incisors,  and  other  very  slender  roots. 

The  taper  post  greatly  increases  the  facility 


of  fixing  as  not  impeding  the  proper  outflow  of 
the  soft  cement  and  air  (see  Fig.  665).  It 
affords  wedgmg  action  on  the  cement  when 
forced  home  finally ;  this  reduces  the  cement  to 
the  smallest  amount,  and  causes  it  along  its 
whole  length  to  set  under  compression. 

On  Taking  an  Impression  of  a  Root  for  Crowning  : 
Also  a  Bite 

The  making  of  a  collar  for  a  cro\\n  requires 
such  a  nicety  of  fitting  that  it  is  best  to  do  it 
direct  to  the  mouth,  using  no  model ;  on  the 
other  hand  the  makmg  of  a  butt-ended  crown 
can  not  only  be  well  done  from  a  good  model. 


Fig.  G66. — Parris's  Crown  Articulator;  showing  im- 
portant parts  cast  by  packing  with  amalgam,  the 
rest  in  plaster. 

{Messrs.  Clavdius  Ash,  Sons  dt  Co.,  Ltd.) 

but  often  more  perfectly  than  would  be  the 
case  if  it  were  done  to  the  mouth.  The  reason 
for  this  difference  is  that  while  it  is  impossible 
to  be  sure  of  obtaiiung  a  perfect  representation 
of  the  sides  of  a  root-end,  unless  it  is  much  coned, 
it  is  quite  possible  as  a  rule  to  get  an  excellent 
impression  of  a  root-face.  For  all  methods  of 
making  a  cro\vn  to  a  model,  except  that  of 
pressure -casting,  a  hard  durable  surface  to  the 
model  is  required,  such  as  amalgam,  fusible 
metal,  or  Harvard  cement,  will  give.  There- 
fore, the  impression  must  be  made  with  some 
material  resistant  enough  to  allow  the  model 
to  be  produced  by  one  of  these  means.  The 
impression-material,  also,  must  be  capable  of 
pushuig  away  the  free  edge  of  the  gum  from 
the  edge  of  the  root.  The  materials  from  which 
choice  can  be   made   for  the   impression  are  : 


555 


^itta-percha,   dental   lac,    crown   composition, 

Harvard  cement,  and  sometimes  plaster  of  Paris. 

Principles  Involved  in  Taking  Impressions  of 

Hoot-Face  with  Root-Hole. — Tlie  dowel-pin  when 


Fig.   667. — Gilbert  Walker's  Impression  Tray  for 
crown-work. 

in  the  root-hole  and  with  an  impression  taken 
over  it  will  very  rarely  allow  itself  to  be  removed 
along   with   the   impression   from   the   mouth ; 


The  first  method  is  accomplished  by  either 
GUbert  Walker's  crown  tray  or  Lennox's  crown 
tray.     The  second  is  accomplished  by  taking 


•      "  — 

Fig.  669. — Impression  consisting  of  "  Core  "  and  ''  Outer 
Impressions  ". 

A.  Core. 

B.  Core  fitted  into  outer  impression  and  secured  ready 

for  casting. 

an  irmer  core  impression  of  canal  and  root -face 
and  an  outer  impression  with  a  crown  tray. 

Technique. — (a)      Gilbert      Wctlkers     Method 
(modified). — File  the  end  of  a  length  of  gold  or 


Fig.   668. — Lennox's  Outfit  for  Impressions. 

(Messrs.  Claudius  Ash,  Sons  <&:  Co.,  Ltd.) 


therefore,  either  the  dowel  must  in  some  way 
be  capable  of  removal  first,  or  part  of  the 
impression  must  be  capable  of  removal  without 
the  dowel. 


Fig.  670. — Simple  home-made  Crown  Tray  for  front 
teeth,  made  by  casting  in  sand  a  tin  form  as  a, 
then  bending  down  the  sides  as  6. 

platinum  \\ire  to  a  correct  taper  to  fit  the  taper 
root-hole.  Fill  the  tray  (Fig.  667  (1))  with  im- 
pression composition,  and  press  the  wire,  E, 
right  through  it.  Warm  the  sur- 
face of  the  composition.  Pass  this 
wu-e,  E,  to  the  top  of  the  root- 
canal,  and  gently  slide  the  tray 
up  it  sufficiently  to  take  a  good 
imisression.  When  the  composi- 
tion has  hardened,  place  the  set 
screw,  F,  close  to  the  handle  of 
the  tray,  G,  and  fix  it.  Withdi'aw 
the  wue — this  can  onlv  be  done  in 
the  direction  of  A  B,Fig.  667  (2) 
and  (3)- — -when  the  impression  may 
be  removed  in  the  direction  of 
CD,  '"  drags  "  or  shifting  of  the 
hole  in  the  composition  made  by 
the  wire  being  avoided.  Replace 
the  vrae,  ^^•hich  will  be  found 
accurately  to  retain  the  relative  position  and 
direction  of  the  root-canal,  while  the  set  screw,  F, 
will  sho\^'  its  proper  depth. 

(h)  Lennox's  Method  (modified). — Fill  a  conical 


556 


cap  of  suitable  size,  which  can  be  made  narrower 
by  pressure,  if  necessary,  so  as  to  pass  readily 
between  the  teeth  adjacent  to  tlie  root,  with 
King's  or  Ash's  cro^\^^  composition.     Pass  one 


Fig.   671. — Three  Crown  Trays. 

{S.  S.  White  Dental  Manufacturing  Co 


of  the  root -canal  posts  through  the  middle  of 
the  composition,  and  through  the  orifice  at  the 
apex  of  the  cap,  a  broach  being  first  used  to 
open  a  way  for  it. 
Soften  the  surface 
of  the  composition 
and  shape  it  into  a 
mound  about  the 
post,  as  shown  in 
Fig.  668.  Pass  the 
post  into  the  canal, 
then  press  the  cap 
home  and  cool  it 
by  means  of  a  syringeful  of  cold  water.  Re- 
move the  cap  and  post,  cut  away  the  superfluous 
composition  on  the  outside  of  the  cap,  and 
press  home  again  on  the  root.     Now  take  the 


outer  impression  with  the  tray  or  a  full-size 
slotted  tray  of  the  same  shape,  in  plaster  of 
Paris ;  during  this  process  tlie  post  is  made  to 
strike  the  centre  of  the  plaster  in  a  dii'ection 
towards  the  front  of  the  tray, 
which  then  guides  it  unerrmgly 
tliroiigh  the  slot.  Slide  the  ferrule 
up  the  free  end  of  the  post  till 
it  strikes  the  tray,  and  fix  it 
there  with  sticky  wax.  Remove 
the  post,  and  then  the  impres- 
sion. Replace  the  post  m  the 
impression,  and  fix  with  sticky 
wax  applied  to  the  tray. 

Two  or  more  roots  may  be 
treated  simultaneously  m  the 
same  impression,  whether  it  be 
a  partial  or  a  full  one. 

(c)  Method  ivith  Core. — For  a 
oro\vn  with  a  single  post,  take 
a  taper  pin  previously  made  to 
fit  the  taper  hole  in  the  root. 
Take  a  diaphragm  of  thin  metal 
rather  larger  than  the  root-end, 
make  its  edges  turn  up  slightly 
towards  the  gum,  shape  it 
roughly  to  the  root-face,  and 
perforate  it  with  a  central  hole ; 
place  it  on  the  root-end,  and 
force  the  taper  pui  through  it 
into  the  hole  in  the  root  as  far 
as  it  will  go.  Remove  the  two 
from  the  root  and  solder  them 
together. 

This  forms  the  disc -dowel 
"support"  for  the  "core  "  im- 
pression. Wet  the  inside  of  the 
root-hole  and  the  root-face  with 
soap  solution  to  prevent  stick- 
ing. Place  a  small  quantity  of 
softened  dental  lac  or  Hill's 
gutta-percha  on  the  root-surface 
of  the  diaphragm,  and  press  it 
home  on  the  root.  Cool  it  with 
ice  water.  Remove  it  from  the  mouth.  This 
forms  the  inner  or  core  impression  (see  Fig. 
669). 


Fig.   672. — Parris's  Crown  Tray. 


It  may  be  found  that  the  lac  or  gutta-percha 
is  so  locked  between  adjacent  teeth  as  to  prevent 
easy  removal.  If  so,  cut  away  the  part  causmg 
the  obstruction  and  also  the  part  squeezed  out 


557 


beyond  the  diaphragm  labially  and  lingually, 
with  a  hot  knife-edge. 

If  any  distortion  has  occurred  in  removal. 


cast  of  the  root-end  is  essential.  To  obtain  this, 
pack  amalgam  carefully  on  to  that  part  of  the 
impression  that  represents  the   root-end,   and 


Fig.  673. — Rhodes's  Crown  Tray. 


(Dental  Manufacturing  Co.,  Ltd.] 


Fig.   674. — Peeso's  Ladle  for  melting  fusible  metal. 

(S.  S.  White  Dental  Manufacturing  Co.) 


press  the  material  again  into  place  on  the 
root,  and  make  sure  that  it  can  be  removed 
without  cau.'iing  distortion.  Soaj)  the  surface 
of  the  core  and  supjjort,  and  while  in 
situ  on  the  root  take  an  miter  impression 
over  it  and  the  adjacent  teeth  with 
plaster  or  comj)osition  in  a  tray. 

For  front  teeth  use  an  ordinary  small 
tray  or  crowii-tray  (Fig.s.  670  and  671). 

For  side  teeth,  if  there  is  room  for  it  a 
Parris's  crown  tray  (see  Fig.  672)  may 
be  used,  but  a  Rhodes's  crown  tray  (see 
Fig.  673)  is  more  univer.sally  applicable. 
With  either  of  these  the  bite  is  taken 
simultaneously  with  the  impression.  If 
an  ordmary  tray  is  used,  take  a  bite 
separately  with  a  small  piece  of  com- 
position, not  too  soft. 

Remove  the  outer  impression,  then 
remove  the  inner  core.  Dry  them  with 
bibulous  paper,  fit  the  core  into  its 
place  in  the  impression,  and  fix  it  there 
with  sticky  wax. 

Samuel  Dosko^\■  recommends  taking 
the  impression  of  the  root-end  witli 
oxy-phosphate  of  zinc  cement  in  a  small 
conical  support  first  nearly  filled  with 
wax;  the  cement  is  placed  on  the  wax, 
and  then  forced  against  the  root-end 
and  held  there  till  it  is  set. 

Casting  the  Model. — For  the  pressure-casting 
method  a  plaster  model,  with  care,  will  suffice, 
but  for  every  other  method  a  hard  and  durable 


carry  the  amalgam  also  into  the  impressions  of 
the  adjacent  surfaces  of  teeth  immediately 
adjoinmg.     Copper  amalgam  will  answer  very 


■■ 11 iiiiiiiM£!iiiiiiiiiiiiiii[iiiiiii»a'iii»g'''«"'i"''''''' 


Fig.   675. — Bench  for  operating-room  for  crown-work. 

[Dental  Manufacturing  Co.,  Ltd.) 

well,  but  takes  forty -eight  hours  to  set ;  any 
other  ordinary  amalgam  will  do  and  will  set 
much  more  quickly. 


558 


Pack  the  amalgam  thoroughly  and  carefully 
into  the  impression,  so  as  to  get  a  perfect 
apposition  without  uijuring  it  at  all.  When  this 
is  set,  cast  the  rest  of  the  model  in  plaster,  and 
also  the  bite. 

The  alternative  plan  is  to  cast  the  model 
with  fusible  metal  (Melotte's  is  a  good  variety). 
Before  running  the  fusible  metal,  wait  till  it 
is  approaching  the  solidifyuig  point,  then  pour 
it  into  the  imj)ression,  and  quickly  press  it  home 
with  a  soft  pad  of  bibulous  paper.  This  fusible 
metal  method  is  strongly  advocated  by  W.  A. 
Rhodes. 

Samuel  Doskow  recommends  casting  the  model 
of  the  root-end  also  ^ith  oxy -phosphate  cement, 
and  emj)loys  glyceruie  to  prevent  sticking  of 
the  oxy-phosphate  model  to  the  oxy-phosi^hate 
impression,  usmg  the  cement  thick,  jjackuig 
it  on  the  impression,  and  holdmg  it  on  under 
pressure  of  the  finger  untU  set.  This  cement 
model  is  mounted  on  plaster. 

To  Take  an  Impression  of  a  Single  Tooth  in 
Composition. — Make  a  conical  cup  by  bending 
up  a  piece  of  sheet  coj)per  or  brass  into  a  cone 


about  half  or  three-quarters  of  an  inch  long, 
and  half  an  uich  broad  at  the  open  end.  Solder 
the  edges  together  (soft  solder).  Cut  out  a  deep 
bay  with  shears  on  two  opposite  sides  of  the 
base.  Fill  this  with  Ash's  crown  composition. 
Cool  the  tray  with  cold  water  and  let  the 
composition  get  rather  stiff.  Soften  the  surface 
of  the  composition  by  holding  it  momentarily 
in  a  flame,  vaseline  the  surface,  and  then  take 
the  impression  by  pressing  it  home.  Cool  with 
cold  water.     When  quite  hard  remove  it. 

For  obtaining  a  plaster  model  only,  T.  A.  Coysh 
recommends  taking  the  impression  m  sticky 
wax  for  the  gold  casting  process,  as  follows  : 
Take  a  piece  of  softened  composition  about  as 
big  as  a  small  walnut,  place  it  on  the  root,  and 
let  the  patient  close  firmly  upon  it.  Wlien 
cool  remove  it.  Dry  it.  Drop  melted  sticky 
wax  mto  the  impression  of  the  root,  cool  the 
opposite  surface  of  the  composition,  wait  until 
the  wax  has  just  solidified,  then  replace  it  in 
the  mouth,  and  again  let  the  patient  bite  home. 
The  composition  acts  as  a  "  special  tray  "  and 
forces  the  wax  into  close  apposition  with  the  root. 


CHAPTER  XXXV 


ARTIFICIAL   CROAVNS     {continued) 


THE    VARIOUS    TYPES    OF    CROWNS 
CONSIDERED    IN    DETAIL 

The  Amalgam  or  Matrix  Crown  (see  Fig.  676). 
The  simi^lest  crown,  and  one  suitable  for  a  molar, 
is  the  amalgam  crown  or  matrix  crown,  which 
is  a  restoration  of  a  natural  crown  by  amalgam 
built  up  within  a  matrix  band  and  around  posts 
previously  set   in  the   roots.     This  is   perhaps 


f^=^ 


Fig.  676. — The  Matrix  Crown,  (a)  Root  with  posts  fixed ; 
(6)  Strip  of  n:ietal  for  matrix;  (c)  Matrix  formed  and 
notched ;  (d)  Same  contoured  and  wired  round  the 
occlusal  angle. 

the  most  practical  and  effective  method  of 
restoring  a  very  bad  molar  root  that  is  deficient 
under  the  gum. 

The  matrix  band  may  be  made  of  a  strip  of 
gold  or  platinum  about  No.  4  gauge,  fitted  to 
the  circumference   of  the   root,   fitted  also  to 


a  natural  contour.  //  to  be  left  on  as  a  per- 
manency, the  edge  formmg  the  occlusal  end  of 
the  band  should  be  bent  inwards  all  round 
towards  the  centre  of  the  crown  to  avoid  a 
rectangular  edge  ;  and  little  V-shaped  portions 
should  be  cut  out  of  it  if  necessary  to  facilitate 
it  bemg  thus  contracted,  and  then  soldered  up. 
All  excellent  plan  suggested  by  L.  Mathesoii 
is  that  of  soldering  a  fine  wire  round  the  uiside 
of  the  occlusal  edge  to  reinforce  it,  and 
to  prevent  its  being  hammered  out  of  shape 
by  the  impact  of  the  bite  hi  mastication. 
//  to  be  removed  after  the  amalgam  has  set, 
the  band  need  not  be  much  contoured  nor 
reuiforced.  The  removal  will  be  effected  by 
cutthig  tlirough  tlie  band  with  a  fine  fissure- 
burr  on  a  day  subsequent  to  the  packing  of 
the  amalgam.  The  correct  contour,  par- 
ticularly on  the  buccal  and  lingual  sides,  will 
then  be  produced  by  grinding  with  a  car- 
borundum wheel,  and  the  interstitial  cervical 
edges  will  require  trimming  with  a  fine  flexible 
chisel,  or  by  stones  and  finishing  burrs  where 
there  is  sufficient  access.  The  whole  will  then 
require  polishing. 

Any  amalgam  in  ordinary  use  is  suitable  for 


Fig.  677. — Carborimdiun  Points  for  contouring  surfaces. 
(S.  S.  White  Dental  Mamijaeluriny  Co.) 


the  bite,  and  with  the  edges  soldered  together ; 
or  it  may  be  made  of  a  piece  of  seamless  tube. 
This  matrix  can  be  left  on  permanently,  or  it 
may  be  made  of  German  silver  and  removed 
after  the  amalgam  has  set.  In  either  case  the 
matrix  must  be  nicely  and  accurately  fitted 
around  the  edge  of  the  root  and  contoured  to 


559 


the  purpose  except  copper  amalgam.  No  fear 
need  be  entertained  of  a  siLver-alloy  amalgam 
destroying  a  gold  matrix,  as  amalgamation  of 
the  gold  wiU  only  occur  very  superficially  and 
can  be  entirely  jjievented  by  previously  dipping 
the  band  in  " chloro-percha  "  or  "copal  ether  ". 
Copper  amalgam,  on  the  other  hand,  eventually 


560 


destroys  a  gold  matrix,  as  the  mercury  continues 
to  pass  from  the  amalgam  uito  the  gold  even 
long  after  the  amalgam  has  set,  in  fact,  no 
matter  how  long  after. 

Technique :  Preparation  of  Root. — If  buried, 
the  root  must  be  fully  exposed  by  the  method 
already  described  (see  p.  552).     Then  enlarge 


Fig. 


-Lennox's  Pliers  for  driving  posts  into 
lower  molar  roots. 


and  prepare  each  root-canal  for  a  post  if  possible. 
Remove  every  particle  of  carious  softening  from 
the  root.  Fit  a  post  to  each  prepared  root- 
canal  and  try  them  to  the  bite.  Fix  them  with 
either  cement  or  gutta-percha.  If  any  jjortion 
of  the  natural  crown  remains,  trim  with  car- 
borundum  points    (see   Fig.    677)   in  order   to 


1  2  3 

Fig.  679. — Showing  upper  molar;  (1)  before  trim- 
ming; (2)  trimmed;  (3)  posts  fixed  and  crown 
fixed  (in  section). 

remove  any  bulging  of  the  sides.  Now  proceed 
to  make  the  band.  Supposing  the  band  is 
to  be  left  on  permanently,  take  a  straight 
strip  of  Xo.  4  gold,  22-carat  or  soft  platinum ; 
bend  it  with  pliers  to  the  outline  of  the 
edge  of  the  root-face ;  and  festoon  it  M'itli 
scissors  at  the  cervical  edge  to  correspond 
with  the  edge  of  the  root.       Solder  the  ends 


11 


of  the  band  together  with  gold  solder.     Bevel 

the  cervical  edge  with  a  file  or  grinding  wheel 

at  the  expense  of  the  outer  surface.     Make  the 

band  fit  tightly  over  the  edge  of  the  root  where 

the  edge  is  sufficiently  pronounced,  and  just 

flush  with  the  edge   where 

it  is  much  buried.    Try  the 

bite  upon  it  and  adjust  it  to 

the  bite.     Contour  the  sides 

of  the  band  with  contouring 

pliers  to  resemble  the  form 

of  a  natural  tooth,  turnmg 

the  buccal  and  lingual  edges 

strongly    inwards   so   as  to 

present  no  sharj)  edge  to  the 

cheek  or  tongue.     Fit  a  thui 

wire,    as    recommended    by 

Matheson,  to  the  inside  of 

the  occlusal  edge  all  round, 

and  solder  it  on  with  gold 

solder.      Glass  -  paper    and 

polish  the  band. 

Fixing  and  Filling. — It  is 
assumed  that  the  posts  are 
already    fixed.      Hold     the 

band  in  position  on  the  root 
firmly  with  finger  and  thumb 
of  the  left  hand.  Dry  the 
root-face  and  posts  tho- 
roughly.      Pack     amalgam 

around    posts    and     inside 

band,     using     the     plugger 

alternately  on   one  side    of 

the  posts  and  then  on  the 

other,  usmg  equal  force  and 

holdmg  the  band  firmly  with 

the  fingers ;   in  this  way  the 

band  can  be  prevented  from 

movmg.  Force  the  amalgam 

well  down  with  a  flat  small- 
ended  jDlugger  into  the  retir- 
ing angle  between  the  band 

and    the   root,  so    that    no 

interstice     is    left    unfilled. 

Pack    in    more    and    more 

amalgam  untU  the  masticat- 
ing surface  is  reached  and 

properly  buUt  up.     In  cases 

where  the  edges  of  the  root 

are  not  much  buried,  it  will 

be  easy  to  make  the  band 

grip   so   tightly   that    there 

will  be  no  tendency  to  sliift 

during  the  packing,  but  in 

these  cases  the  overlap  of  the  band  must  be 

luted  with  gutta-percha  or  cement  as  follows. 
Dry  the  root,  paint  the  outer  sides  of  the  root 

with  chloro-percha,  and  attach  a  small  amount 

of  gutta-percha  to  the  iiuier  sides  of  the  cervical 

edge  of  the  band  (warmed).     While  fairly  hot 

press  the  band  to  place  on  the  root.     Pack  down 


Fig.  680.  —  Kirk's 
Exact  Dentimeter. 

{Denial  Manufactur- 
ing Co.,  Ltd.) 


561 


the  gutta-percha  inside  the  band  tightly  into 
the  retiring  angle.  Burn  off  the  excess  inside 
with  a  very  hot  bulb-ended  plugger.  Then 
pack  full  of  amalgam  as  before  ;.  or  as  an  alterna- 
tive use  cement  and  amalgam  (PcA,  i.  e.  phos- 
phate cum  amalgam).  If  desired,  the  band  can 
be  made  m  the  workroom  to  a  model  instead 
of  to  the  root  in  the  mouth  direct. 

PcA.- — The  wTiter  here  desires  to  explain 
what  he  intends  to  convey  by  the  formula  PcA. 
It  denotes  phosphate  cement  and  amalgam  used 
in  combmation  by  his  method,  which  is  the 
same  as  that  mtroduced  by  him  for  filling  teeth 
(3)  (5). 

Technique  for  working  PcA. — First  mix  the 
amalgam  (rather  soft) ;  then  dry  the  tooth  ;  then 


Fig.  C81.  Case's  Enamel  Cleavers. 

{Dental  Manujacturing  Co.,  Ltd.) 

mix  the  cement.  Place  some  of  the  cement  into 
the  cavity  to  be  filled;  i.  e.  in  this  case,  smear 
the  inside  of  the  band  and  outside  of  the  root 
w  ith  thm  oxy-phosphate.  Press  the  band  into 
place  on  the  root,  and  while  the  cement  Ls  still 
fully  soft,  ckive  the  amalgam  mto  it.  Trim 
away  excess  of  cement  and  completely  clear  all 
edges ;   then  fill  up  tightly  with  amalgam. 

The  effect  of  this  is  that  the  cement  and 
amalgam  are  inseparably  united  together.  The 
cement  is  driven  into  the  smallest  and  remotest 
interstices  and  sets  under  compression.  The 
cement  adlieres  strongly  to  the  walls  of 
the  cavity  and  is  completely  protected  from 
the  saliva  and  from  attrition  (3)  (5). 


The  All-Gold  Crown 

This  is  perhaps  the  commonest  form  of  crown  ; 
it  goes  also  by  the  names  of  the  cap  crown, 
shell  crown,  and  barrel  crown,  and  is  frequently 
made  of  other  metals  than  gold,  notably 
platinum. 

This  crow  n  w  h  e  n 
finished  forms  a  hoUow 
shell  of  gold  of  similar 
shape  to  the  natural 
crown  that  it  represents, 
and  is  the  crown  best 
suited  for  ordinary  re- 
quirements in  the  molar 
region.  It  is  simple  in 
construction  and  very 
durable,  and  has  the  great 
merit  of  not  requii'ing  the 
remains  of  the  natural 
tooth  to  be  all  cut  down 
to  the  gura  level,  as  they 
can  to  a  large  extent  be 
enclosed  withm  it. 

Pre  faring  the  Root. 
The  root  or  remains  of 
the  natural  crown  must 
be  so  trimmed  or  reduced 
that  the  cervix  becomes 
its  broadest  part ;  in  other 
words,  all  the  natural 
bulge  of  the  natural  crown 
must  be  more  than  re- 
moved. This  is  to  allow 
the  artificial  crown  to  be 
pushed  on  when  being 
fixed,  so  that  the  cervical 
edge  of  the  artificial 
crowai  will  grip  quite 
closely  and  form  no  pro- 
jection. 

Wliether  or  not  the 
cervix,  or  the  part  that  is 
to  be  gripped,  is  the 
largest  part,  can  be  deter- 
mined by  passing  a  loop 
of  binding  wire  in  a 
"  dentimeter  "  round  it, 
and  tightenmg  it  up  by 
twisting.  If  the  wire  can 
then  be  lifted  over  the 
remams  of  the  natural 
crowai  easily,  no  further 
reduction  is  necessary. 
To  effect  the  reduction, 
the    buccal    and    lingual 

sides  can  easUy  be  trimmed  down  with  car- 
borundum wheels  moistened  with  dilute  lysoform 
and  sprmkled  with  fine  carborundum  powder; 
and  the  approximal  sides  can  be  cut  away 
with  diamond  discs  dipped  in  the  same.    (For 


Fig. 


-MitcheU's 


Root  Trimmers. 
(Dental  Manujacturing 
Co.,  Ltd.) 


562 


technique  of  use  of  diamond  discs  interstitially 
see  p.  551.) 

Overhanging  enamel  can  be  pulled  off  easily 
with    Case's   enamel-removers    (see   Fig.    681), 


Fig.  683. — Enamel  Chisels  for  shaving  approximal 
edges,  chiefly  by  a  pulling  action. 

{S.  S.  White  Dental  Manufacturing  Co.) 

and   where   the    tooth    is    carious    or    broken 
down  level  with  the  gum,  overlianging  enamel 
may    be    pulled    off    with    a    sharp    straight- 
necked  Howe'.s  scaler,  or  where  there  is  room 
for  it,  with  the  more  powerful 
instrument  of  the  same  shape 
designed  by  Mitchell  (see  Fig. 
682).     All  these  instruments 
are  used  with  a  jDuUuig  action 
in  a  direction  a^ay  from  the 
gum.  Small  stones  and  fissure- 
burrs  will  sometimes  assist  in 
removing    corners,    and    the 
flexo-file    will    sometimes    be 
required,  particularly  for  the 
posterior  surface  of  the  second 
lower  molars.     The   flexo-file 
should  be  bent  at  an  angle 
of    30°,    and    the    part    not 
actually  engaged    in   cutting 
should  be  Avrapped  ui  bibulous 
paper  to  protect  the  corner  of 
the  mouth.     There  is  a  useful 
holder  by  Ivory  for  holding 
small  pieces  of  flexo-file  at  the 
correct  angle   (see  Fig.   684). 
He  also  makes   a   useful   set 
of  rififlers,  which  may  be  em- 
ployed  in   preparmg    a    root 
(see  Fig.  685).     Fmally,  any 
overhanging   portions   in    in- 
accessible places  can   be   re- 
moved   with    curved   enamel 
chisels.  Abbot's,  or  with  the 
Fio.  684.-lvory-s  *^i"  chisel-shaped  instruments 
Flexo-filo  Holder,   included  m  the  set  oi  Gvishmg  s 
(I  natural  size.)     scalers.     The  latter  are  used 
chiefly  in  a  horizontal  direc- 
tion between  the  teeth,  and  with   a   pushmg 
action.     The    Abbot's   curved    enamel    chisels 
also    are    chiefly   used    by   a   pushmg   action, 
leverage  being  employed  in  a  rocking  mamier. 


with  the  tip  of  the  middle  finger  restuig  upon 
a  neighbouring  tooth  as  a  fulcrum. 

Making  the  Crown. — First  make  the  band 
(forming  the  sides  of  the  crown),  then  make  the 
top  (forming  the  occlusal  surface),  and  then 
solder  them  together  (see  Fig.  687). 

Making  the  Band  Direct  to  the  Root. — Take  a 
straight  strip  of  22-carat  gold.  No.  4,  long  enough 
to  encircle  the  cervix  and  wide  enough  to 
equal  the  depth  of  the  cro-\vn  at  its  deepest  part, 
i.  e.  from  where  the  edge  of  the  root  is  most 
broken  down  to  the  masticating  surface.  A 
rough  measure  of  the  circumference  of  the 
root  can  be  taken  with  a  thin  copper  strip. 


I 


Fig.   085. — Ivory's  RifHers  for  trimming  cervical  edges 
(by  a  pulling  action). 

Now  carefully  observe,  in  the  mind's  eye, 
the  shape  of  the  circumference  of  the  cervix, 
i.  e.  the  imaginary  outline  if  cross -sectioned  at 
the  cervix  (compare  Figs.  632,  633).  Bend  the 
strip  of  gold  \\  ith  crowning  pliers  as  nearly  as 
possible  to  this  shape.  Anneal  it  in  a  Bunsen 
flame.  Try  it  on  the  root  and  bend  it  ^^•here 
necessary  to  procure  a  more  accurate  fit.  While 
on  the  root  jiress  it  up  into  shape  with  thin  flat 
or  curved  burnishers  and  pinch  it  up  \^ith  the 
writer's  crown-forming  jjliers  (see  Fig.  690),  but 
all  the  time  keeping  the  sides  of  the  band  parallel 


563 


to  each  other  and  not  as  yet  allowing  for  any      of  the  gum  is  most  advanced,  there  the  band 


contouring. 

Now  festoon  the  cervical 
edge  of  the  band  with  scissors 
to  allow  it  to  follow  the  edge 
of  the  gum  at   its   varying 


is  to  be  most  cut  away  to  form  its  counterpart. 


P 


687. — (1)  Strip  of  gold,  No.  4,  22  carat;  (2)  Band;  (3)  Band  festooned  to 
avoid  injuring  gum;  (4)  Band  contoured.  [The  gingival  edge  is  not  inter- 
fered with  by  contouring,  but  this  part  of  tlie  band  (a)  is  left  with  sides 
strictly  parallel.]  (5)  Zinc  die  for  striking  up  top;  (6)  Piece  of  crown  gold 
struck  between  zinc  die  and  a  piece  of  lead  as  a  counter;  (7)  Top  trimmed 
and  filled  solid  with  gold  solder;  (8)  Top  soldered  to  band;  (9)  Crown 
stuck  on  a  piece  of  wood  with  shellac  for  polishing. 


Fig.  686. — Byng's  Forceps  for  coning  root-end.  One 
jaw  is  a  strong  sharp  blade,  and  cuts  by  being 
rotated  round  the  other,  which  is  centred  in  the 
root-canal. 

heights.  Where  the  root  is  most  deficient,  and 
therefore  its  edge  most  under  tlie  gum,  tlie  band 
must  be  left  full  depth ;   ^^  here  the  attachment 


Fig.  688. — How's  Crown  Pliers. 
(jS.  S.  White  Dental  Manujacturing  Co.) 


564 


To  assist  in  this  process  the  band  may  be 
marked  with  a  sharp-pointed  probe,  a  line 
being  drawn  in  a  curve  parallel  to  the  edge 
of  the  gum,  and  the  band  then  cut  with  scissors 
along  this  line.  Now  smooth  the  cut  edge  and 
bevel  it  at  the  expense  of  its  outer  surface  with 
a  file  or  lathe  wheel;  the  best  tool  for  this 
purpose  is  a  fine  carborundum  wheel  running 
at  high  speed  on  the  electric  lathe  (see  Fig. 
693).     Now   try  the   band   on  the  root;    if  a 


Heat  is  applied  at  first  all  over,  then  the  flame 
is  particularly  directed  to  the  parts  which  are 


Fig.  689. — Peeso's  Crown  Pliers. 

{S.  S.  White  Dental  Manufacturing  Co.) 

loose  fit  on  the  cervix  cut  away  a  strip  from 
one  end  of  the  band.  Adjust  the  ends  ac- 
curately together  and  solder  them  with  gold 
solder  to  form  a  butt-ended  joint,  using  only 
a  small  amount  of  solder ;  or  sweat  the  ends 
together  without  solder.  The  process  of  sweat- 
ing joints  is  thus  described  by  Mr.  Dall  :  "In 
the  case  of  a  lap  jouit  the  two  ends  of  the 
intended  band  are  made  very  thin  either  by 
rolling  or  hammering ;  they  are  closely  over- 
lapped   and    painted    with    very    thin    borax. 


Fig.  690. — Special  Pliers  for  pinching  band  into  shape 
on  root-end. 


Fig.   691. — Burnishers  for  pressing  band  to 
(Dental  Manufacturing  C 

to  be  sweated.     In  the  case  of  a  butt-joint  the 
ends  are  not  thinned  but  brought  close  together, 


565 


Fig.  693. — "  Cokunbia 


'  Electric  Lathe  :  Ritter  Dental  Manufactm-ing  Company. 

(Dental  Manujacturing  Co.,  Ltd.) 


end  to  end,  borax  is  used 
and  they  are  sweated  in  the 
same  way." 

Now  carefully  but  firmly 
work  the  band  into  place 
on  the  tooth,  using  a  rock- 
ing pressure  to  force  it 
home.  If  it  whitens  the 
gum  at  any  particular  point 
Jl  by  undue  pressure,  remove 

it  and  cut  away  at  this 
part  and  try  it  on  again. 
Repeat  this  process  until 
the  edge  of  the  band  over- 
laps slightly  the  most  re- 
mote edge  of  the  root,  while 
not  pressing  unduly  on  the 
most  advanced  portion  of 
the  gum.  The  band  need 
not  cover  all  the  visible 
part  of  the  tooth,  but  there 
is  no  objection  to  its  passing 
under  the  free  edge  of  the 
gum  provided  it  ls  quite 
tight  against  the  root  there, 
and  it  is  important  that 
it  should  reach  and  slightly 
Fig.  692. — Flat-ended  overlap  all  buried  edges  of 
band-modelling  tool  root  so  as  to  grip  effectively 
for    pressing    band  everywhere.    The  object  is 

close     to    root-end;   ,  j.      j.-   i  i.        •        n  i 

one    end    thin,    the  *«  S^t  a  tight  grip  all  round 
other  tliick.  witliout   any  painful  pres- 

sure on  any  part  of  the  gum, 
and  without  destroying  part  of  the  attachment  of 
the  soft  tissues  to  the  root.  The  band  should  be 
so  tight  that  it  requires  rocking  into  place,  using 
a  piece  of  boxwood  as  a  rocker  (see  Fig.  696). 


Contracting  the  Band. 
If  the  band  prove  too 
loose,  remove  it  and  cut 
a  section  with  scissors 
out  of  it,  mcluding  the 
soldered  joint.  This  can 
be  neatly  done  if  only  a 
small  amount  of  solder 
has  been  u.sed.  Readjust 
the  edges  together  and 
resolder.  Try  on  again, 
and  if  necessary  repeat 
this  contracting  process 
several  times,  until  the 
band  is  sufficiently  con- 
tracted  to  require 
forcibly  rocking  into 
place. 

Expanding  the  Band. 
If  the  band  prove  too 
tight  expand  it  by 
squeezmg  the  medial  and 
distal  sides  with  band- 
expandmg  pliers  until 
it  becomes  large  enough. 
Peeso's  so-called  stretch- 
ing pliers  are  excellent 
for  this  purpose,  but  the 
process  is  not  one  of 
stretching  but  of  ex- 
panding by  compression 
of  the  metal  (see  Fig. 
697). 

E.vpanding  the  Band 
in  Part  Only. — If  it  be 
found  that  the  band 
fits  well,  except  that  at 


m 


Fig.  694. — Angle's  Band- 
soldering  Pliers. 
(S.  S.  White  Dental 
Manufacturing  Co.) 


566 


one  part  it  is  too  contracted  to  encircle  some 
projecting  edge  of  the  root  under  the  gum, 
proceed  as  follows  :  Scratch  two  marks  on  the 
outside  of  the  band  to  indicate  the  limits  of 
the  portion  that  requires 
expanding.  Embed  the  band 
closely  inside  and  out  in 
Ash's  crown  composition,  or 
in  sliellac.  With  a  knife 
cut  away  the  embedding 
material  outside  the  band 
between  the  two  marks  (see 
Fig.  698).  Thorouglily  cool 
and  harden  the  whole  in 
cold  water.  Now  force  a  flat 
burnisher  or  band-modellmg 
tool  (see  Fig.  692)  between 
the  band  and  the  embedding 
material  inside  the  part  re- 
quirmg  expansion.  This  will 
stretch  the  band  locally  at 
the  desired  spot  without  m- 
terfering  ^^•ith  the  shape  of 
the  band  elsewhere.  Remove 
the  band  from  its  bed  by 
heating  its  edge.  Try  it  on 
the  root.  If  found  too  much 
stretched,  embed  it  again. 
Cut  away  the  bed  on  each 
side  of  the  part  to  be  con- 
tracted ;  then  effect  the  con- 
traction by  burnishmg  down 
or  by  tapping  with  a  light 
riveting  hammer. 

Spare  no  time  or  trouble 
in  fitting  the  band  as  per- 
fectly as  possible.  Wlien  in 
place  on  the  root  it  should 
be  impossible  to  msinuate 
the  point  of  a  fine  Donaldson 
)>rist  le  between  the  band  and 
the  root  at  any  j)oint. 

Wlien  fitted  to  this  degree 
of  perfection,  the  next  pro- 
ceeding is  to  "contour  "it, 
?'.  e.  to  round  its  buccal  and 
lingual  sides,  and  to  bulge 
its  medial  and  distal  sides  so 
Fig.   695.  — Serrated  that  they  Can  form  a  natural 
Pluggers  for  press-  contact  with  adjoining  teeth, 
ing  band  to  buccal       Contouring      the      Band. 
or  liiigual  wall  of  The  necessary  rounding  and 
/  r^  °°  , ' ,  ^       ,  bulging    of    the    sides    to 

"S  CoTluiT'  P™d"ce  a  natural  contour 
can  be  done  by  the  judicious 
use  of  contouring  pliers  (see  Fig.  699),  but  great 
care  must  be  taken  not  to  alter  its  sliape  or  size 
at  the  cervical  portion. 

Occlusion :  Taking  the  "  Bite  ".—Try  the  band 
on  the  root  and  adjust  it  so  that  it  does  not 
interfere  with  the  "  bite  ". 


Now  take  the  "  bite  ".  First  nearly  fill  up 
the  band  inside  with  pink  wax.  Then  place 
either  a  small  quantity  of  plaster  of  Paris  or  of 
composition  on  the  top  and  let  the  patient 
close  the  teeth  tightly  home.  The  mechanic 
will  now  cast  a  model  from  this,  and  a  "  bite  ", 
either  on  a  crowii  articulator  or  by  making  the 
simple  plaster  articulation.  After  separating 
the   "  bite  "  from  the  model,  cover  the  forms 


1^   ■'■ 


Fig.   696.- — (a)  Boxwood    tool    for    "rocking"    snaall 
bands  on  to  roots;  (6)  Large  boxwood  "  rocker". 
{Dental  Manujacturing  Co.,  Ltd.) 

of  the  cusps  that  will  occlude  with  the  crown 
with  tin  foil  stuck  with  wax. 

Rhodes' s  Crown  Tray. — Instead  of  taking  the 
"  bite  "  in  the  simple  way  mentioned  above,  a 
better  way  is  to  use  a  Rhodes 's  crown  tray 
(see  Fig.  673),  and  with  it  secure  an  impres- 
sion of  all  the  adjacent  teeth  with  band  in 
situ  and  of  the  occluding  teeth  at  one  and 
the  same  time   by  the  patient's   ovm   act   of 


567 


occlusion,  but  before  doing  this  fill  the  band 
almost  completely  when  in  situ  in  the  mouth 
with  wax,  to  prevent  the  impression  material 
entering  it  much.  On  removing  the  tray 
from  the  mouth  the  band  will  be  found  still 
on   the   root.     Therefore,   detach   it   from   the 


Fig.  697. — Peeso's  so-called  "  Stretching  "  and 
Contouring  Pliers. 

(Dental  Mamifacturing  Co.,  Ltd.) 

root  and  carefully  replace  it  in  its  bed  in  the 
impression  and  fix  it  there  by  meltmg  wax 
inside  before  casting  the  plaster  model.  Suf- 
ficient wax  in  a  thin  film  should  be  melted 
inside  to  allow  the  band  to  be  easUy  removed 
from  the  model  \\hen  desired. 

(a)  Supplying  the  Top  by  Striking  up  Plate. 
Strike  up  a  top  to  form  the  occlusal  surface  out 


of  Xo.  6,  7,  or  8  gold  plate,  22-carat,  usmg  a 
zmc  die  (see  Fig.  687)  made  from  a  natural 
tooth  of  suitable  size  and  shape,  and  a  flat 
piece  of  lead  as  a  "counter".  Or  the  striking 
up  may  be  done  by  striking  a  button  of  lead 
into  a  steel  or  gun-metal  die  plate  (see  Fig. 
700) ;  or  by  striking  with  a  zinc  cast  of  the 
actual  tooth  being  crowned  and  a  lead  counter, 


Fig.  698. — Band  embedded  in  composition,  which  is 
cut  away  between  two  marks  where  it  is  desired 
to  expand  the  band. 

this  last  being  the  method  to  adopt  when  the 
masticating  surface  or  much  of  it  is  preserved, 
and  it  is  desired  not  to  cut  it  dowii.  The  need 
for  this  arises  when,  owing  to  the  tooth  beino- 
still  alive  and  sensitive,  or  the  patient  being 
easily  tired  or  nervous,  it  is  desired  to  do  a 
minimum  of  the  grmding  down  that  ^^-ould 
otherwise  be  necessary,  and  at  tlie  same  time 


Fig.  699. — Johnson's  Contouring  Pliers. 

(Dental  JManiifacturing  Co.,  Ltd.) 

to  prevent  the  bite  from  being  raised  by  the 
additional  thickness  of  metal. 

Adjust  the  top,  when  struck,  to  the  edge  of 
the  band  and  to  the  bite,  and  then  solder  it  on 
with  gold  solder,  holdmg  the  parts  together 
meanwhile  either  with  bindmg  wire  or  a  soldering 
clamp.  Reinforce  the  cusps  by  melting  gold 
solder  into  the  inside  of  them. 

{b)  By  the  Gold  Pressure-casting  Process  (see 


568 


Fig.  702) — alternative  to  (a). — Fill  the  band  with 
gold-casting  investment.  Build  up  the  rest  of 
the  form.  i.  e.  the  occlusal  surface,  with  the  same, 


{5r   ff^  #*               *»-    ^>' 

K  %  %  C,  5/  7, 

C^  C^  ^  ^  ff  p 

^.  7^  a  C^  ^  ^ 

#•*♦#•  ^  #^  *^  /*■ 

6f<«-  1^  m  y::^  ♦*?    tM?  *?!*' 

C"  CT  f/,  :r  ^ '-  c^ 

iC^  s;  JT  J?  ST  ^  5? 

tr-c*.  C^  ^  r.  «^ 

.C  t  e  c  C  cr ;?  *  c 

■«.    ••  ir    •f  V    wr  *   •>   w 

.  A  «»  ^  #>   <»    ^  4»    Jk    #•> 

«      IT       H*^     W       V      «•      «     «     «^ 

w      <•     •     W     IT     V     w       <•'«-- 

♦      V■5»l^      mi     W    Z'   ^    m 

ererr^re 

f.  ?i  e  e  e  e  e  e 

«■    «     »     *           »       ,.    ,» 

f'c'eff'r.  e*f 

■  c?  ffr  ^  ct  C  5^ 

r^  fTn  0*  ^m  ^m  0* 

»*.i»'  Vin  V^F-  *»!^'   \it#    '-  "■ 

Fio.   700. — Ajax  Die-plate. 

{Dental  Manufacturing  Co 


but  making  it  short  of  the  bite  by  the  thickness 
it  is  desired  the  top  sliall  be.     Cover  this  with 


Fig.   701. — Contouring  Pliers,  for  contoiu-ing 
occlusal  surfaces. 
{Messrs.  Claudius  Ash,  Sons  ds  Co.,  Lid.) 

casting-wax  and  articulate  the  wax  to  the  bite. 
Attach  a  sprue  to  some  part  of  this  wa.x  and 
pressure-cast  it  either  m  Solbrig's  pliers  or  one 


of  the  numerous  machines  devised  for  pressure- 
casting.  In  this  way  the  top  is  cast  direct  on 
to  the  band,  and  it  can  be  managed  at  the  same 
time  to  thicken  the  band  on 
the  outside  to  any  desired 
extent  and  to  improve  the 
lateral  contours  by  added 
gold. 

J.  E.  Dunwoody,  PhUa- 
delj)liia  (10),  recommends 
makmg  the  occlusal  portion 
in  the  following  way  :  After 
the  band  is  made,  j)ut  it  on 
the  tooth.  Place  in  it  a 
small  amount  of  modelling 
composition.  Let  the  patient 
close  the  teeth  upon  it.  Re- 
move band  and  separate  the 
composition  from  the  band. 
Carve  the  composition  to  fit 
the  opposing  teeth  and  to  fit 
the  band.  Remove  all  com- 
position from  uaside.  Lay  the 
composition  flat  down  on  a 
glass  slab.  Pour  over  it  two- 
thirds  of  plaster  of  Paris  and 
one-third  of  medium  marble 
dust.  Lito  the  mould  thus 
made,  melt  gold  without  borax  and  produce 
pressure  on  it  with  a  piece  of  charcoal  to  force 

'     ^^ 


Ltd.) 


(3)  (4) 

Fig.  702. — (1)  Band  filled  with  investing  material,  with 
tinfoil  inserted  between  the  investing  material  and 
the  counterpart.  (2)  The  band  with  masticating 
surface  in  wax,  and  sprue-wire  attached  with  sticky 
wax.  (3)  The  band  with  the  masticating  surface 
in  wax  is  shown  placed  upon  the  cone  and  sur- 
rounded by  the  cylinder.  (4)  Section  of  the  cyUnder 
filled  with  embedding  material,  with  the  cone  and 
the  metal  point  removed,  (a)  Plaster  of  Paris ; 
(6)  Tinfoil;  (c)  Investing  material;  {d)  Wax;  (e) 
Sticky  wax  ;   (/)  Sprue-wire  ;  (</)   Gold. 

it  into  every  interstice.     The  result  will  be  a  per- 
fect reproduction  of  the  modelling  composition, 


56y 


and  will  fit  the  band  and  the  bite  correctly. 
Solder  this  top  to  the  band. 

Finishing  the  Crown. — Mount  the  crowii  on  a 
stick  of  wood  covered  with  shellac  and  let  the 
shellac  entirely  fiU  the  crown.  This  will  preserve 
the  shape  of  the  crown.  Now  fiJe  up,  glass- 
paper  and  polish  the  crowai,  takuig  great  care 
not  to  over-polish  the  sides,  as  they  may  easily 
be  unduly  thinned  by  this  process.  On  re- 
movuig  from  the  support,  finish  off  the  cervical 
edge  of  the  cro\vn  very  finely  with  glass-paper, 
and  then  with  blue-black  emery  paper,  so  that 
aU  traces  of  file  marks  are  eradicated  from  it, 
as  this  is  the  part  that  it  is  most  important  to 


cated  for  the  ordinary  run  of  cases  that  are 
met  with  ui  practice.  Operators  who  wish 
to  try  the  method  ^^ill  find  an  accoinit  of  it  in 
S.  S.  White's  Catalogue. 

Seamless  Crowns. — These  are  swaged  from  a 
ready-made  gold  ferrule  or  gold  shell,  and  can 
be  made  to  assume  a  very  artistic  and  natural 
shape ;  but  the  fit  can  oiily  be  relied  on  in  the 
case  of  easy  roots.  A  model  of  the  crown  as 
it  is  to  be  when  fuiished  is  made,  firstly,  by 
fitting  a  copper  band  to  the  root  in  the  ordinary 
way ;  secondly,  adding  to  this  plaster  or  com- 
position and  carving  it  to  the  shape  of  the 
finished  cro\vn.  This  model  tooth  is  placed  in 
a  ca.sting  rmg,  and  fusible  metal  is  poured 
around  it  to  form  a  counter-die.  This  counter- 
die  is  then  split  in  two  longitudinally  and  the 
model  of  the  crown  taken  out.  The  ready-made 
gold  shell  is  swaged  into  the  space  so  formed 
in  the  counter-die  by  forcing  unvulcanized 
rubber  into  it  in  a  small  swaguig  machine,  one 
variety   of   which    is   contained   in    The   Prac- 


!he  Practical  Crown  Outfit 
Swajjinj:  De\jce 


«%       1'*%^ 


Fig.  703. — The  Practical  Crown  Outfit  and  Swaging  Device ; 


Ransom  and  Randolph  Company. 

(Dental  Manufacturing  Co.,  Ltd.) 


have  smooth  and  self -cleansing,  as  far  as  may 
be,  in  the  mouth. 

Other  Methods  of  Making  Gold  Shell  Crowns. 
The  band  for  a  shell  cro^vn  may  be  made  out 
of  a  seamless  piece  of  tube,  instead  of  being  made 
out  of  a  strip.  Lengths  of  tube  are  sold  for  this 
purj)ose  in  many  diameters.  The  soldered 
Jomt  is  hereby  obviated,  but  in  difficult  cases 
the  fit  is  not  generally  so  good,  and  the  plan  is 
therefore  not  to  be  recommended  as  a  rule. 

HollLugsworth  has  mtroduced  a  rather  elabor- 
ate process  of  striking  up  shell  crowns  in  two 
longitudinal  halves,  in  order  to  get  a  contoured 
surface  that  will  closely  imitate  that  of  a  natural 
tooth.  The  two  halves  are  then  soldered  to- 
gether. The  natural  contour  is  a  desirable 
feature,  but  the  process  is  rather  too  compli- 


tical  Croivn  Outfit  and  Swaging  Device  of  the 
Ransom  &  Randolph  Company  (see  Fig.  703). 

The  weak  part  of  the  proposition  is  that  the 
sides  of  the  crown  are  a  reproduction  of  the 
actual  band  that  was  fitted  to  tlie  root  in  the 
mouth,  and  not  the  actual  band  itself.  Repro- 
ductions and  originals,  as  is  well  known,  are 
never  exactly  alike. 

T.  A.  Coysh  recommends  making  cap  crowns 
entirely  l)y  gold-casting,  and  the  writer  is  in- 
debted to  "him  for  the  foUowuig  description  of 
this  method — 

"  This  method  is  designed  so  that  there  may 
be  as  little  work  as  possible  hi  the  mouth. 

"  The  root  is  completely  prepared  in  tlie  usual 
way  and  an  impression  taken.     This  may  be  done 


570 


ill  one  of  two  ways,  according  to  circumstances. 
In  a  case  where  the  tooth  to  be  crowned  stands 
alone,  take  a  piece  of  composition,  about  the 
size  of  a  %\ahuit,  soften  it,  and  place  it  over  the 
root,  and  instruct  the  patient  to  bite  into  it. 
Wien  cool,  remove  and  diy  it,  and  then  melt 
ordinaiy  sticky  wax  upon  that  portion  of  the 
impression  showdng  the  root-surface.  While 
this  is  still  soft,  replace  in  the  mouth  and 
again  get  the  patient  to  bite  firmly  home. 
Before  removal  cliiU  with  cold  water,  so  that 
the  wax  may  be  thoroughly  hardened. 

"  Wliere  the  tooth  to  be  cro\raed  has  teeth 
in  front  and  behind  it,  an  ordinary  ferrule  of 
copper,  slightly  larger  than  the  root,  should 
be  made,  cut  anteriorly  and  posteriorly  to 
tit  over  the  gum,  and  low  enough  to  be  clear  of 
the  bite.  This  ring  is  filled  with  composition 
and  pressed  on  to  the  surface  of  the  root.  Re- 
move and  trim  off  any  surplus  composition  from 
the  outside  of  the  ferrule,  then  replace,  and 
make  use  of  a  small  mass  of  composition,  as  in 
the  previous  method,  and  instruct  the  patient  to 
bite  home.  Fmally,  secure  a  sharp  imjiression 
of  the  root-surface  by  employing  sticky  wax 
as  before.  In  this  manner  a  very  sharp  clean 
impression  of  the  root-surface  is  secured,  and 
usually  the  surplus  wax  is  forced  up  between 
the  root  and  the  gum,  givuig  a  deeper  impression 
of  the  root-margin  than  is  secured  in  the  ordinary 
way.  This  impression  should  be  cast  very  care- 
fully in  plaster,  the  composition  removed,  and 
the  i^laster  trimmed  to  the  lowest  edge  of  the 
root  indicated  by  the  model.  It  is  preferably 
dried  and  stearined.  From  this  point  one  of 
t^\o  methods  of  jarocedure  may  be  followed. 

"  Fnstly,  melt  a  little  wax  to  surround  the 
cervical  margm  of  the  root,  and  build  it  up  to 
a  level  surface.  Then  make  a  ferrule  of  thin 
wax  and  attach  to  the  wax  already  upon  the 
root.  Contour  carefully,  remove  and  cast. 
Trim  the  ferrule  carefully  with  a  file  and  then 
complete  the  crown  in  the  usual  way  by  casting 
the  bite  surface,  or,  if  prefeiTed,  by  swaging 
a  surface  and  soldering  it. 

"  In  a  case  where  the  root  has  teeth  behind  and 
in  front  of  it,  the  model  should  be  embedded  in 
a  sort  of  cradle  of  plaster.  Then  a  saw-cut 
is  made  between  the  root  and  the  adjoining 
teeth  on  either  side,  sufficiently  deep  not  to  cut 
right  through  the  model.  The  model  is  divided 
into  tliree  pieces  by  breaking.  This  facilitates 
the  subsequent  manif)ulatioii  and  contourmg. 
Now,  making  use  of  the  ordinary  mvesting  com- 
pound, slightly  coloured  so  as  to  distinguish  it 
from  the  model,  build  a  mass  upon  the  root- 
model,  and  when  set  carve  to  the  desired  shape 
of  the  cro-\\ii.  The  contour  should  be  completed 
so  as  almost  to  touch  the  adjohiing  teeth,  but 
to  leave  a  little  extra  space  on  the  biting  surface. 
Wax  is  now  melted  tliinly  over  this  investment 


crown,  and  the  \\hole  may  he  easily  removed 
from  the  model ;  a  sprue  wire  is  attached,  the 
crown  is  embedded  m  the  casting  ring,  and  cast 
in  the  usual  fashion. 
I  "  Either  the  ferrule  method  oi  the  plaster- 
i  crown  method  may  be  adopted  for  the  single 
root  standmg  alone,  or  for  the  root  standmg 
between  two  other  teeth.  Such  crowns  will, 
if  care  is  taken  of  the  model  and  an  accurate 
cast  secured,  fit  perfectly.  The  contour  is 
arranged,  and  very  little  adjustment  in  the 
mouth  is  requned,  beyond  the  removal  of  any 
shglit  roughness  left  from  castmg  on  that 
portion  of  the  crown  that  fits  upon  the  root. 
One  has  found  that  interference  with  the  gum 
is  practically  nil,  and  discomfort  during  fitting 
or  after  setting  almost  absent." 

Tuller  recommends  the  Dittmar  method  of 
makmg  a  cast-gold  cap  crown  round  an  inner 
shell  of  thin  'pitre  gold  plate  (17). 

(Dittmar)  Method  of  making  a  Pressure-cast 
Gold  Shell  Crown. — A  band  of  34  American 
gauge  pure  gold  (24-carat),  is  made  and  accur- 
ately fitted  to  the  prepared  root  m  the  usual 
way ;  34-gauge  pure  gold  is  used  because  it 
is  thin  enough  and  soft  enough  to  be  most 
accurately  modelled  to  the  form  of  the  root ; 
this  is  extremely  important.  The  root  should 
be  trimmed  to  a  slight  taper ;  the  34-gauge 
gold  will  stretch  a  little  and  hug  the  root 
closely. 

Now  slit  down  the  sides  of  the  band  from 
the  occlusal  edge  in  numerous  places  to  equal 
dei^th.  Turn  m  the  divisions  to  the  centre, 
lapjiing  one  over  the  other,  and  so  close  the 
toj)  (or  the  band  may  be  capped  by  soldermg 
on  a  flat  piece  at  the  right  height  to  allow  for 
addition  of  a  cast-gold  occlusal  portion).  Adjust 
to  root,  and  take  "  bite  "  with  modelling  com- 
position, including  impression  of  contiguous 
teeth. 

FUl  the  shell  with  silicate  casting  invest- 
ment, and  the  rest  of  the  impression  with 
plaster,  and  cast  the  articulation.  Remove  the 
modelluig  composition,  and  oil  the  plaster 
model  around  the  crown,  and  also  the  sides 
of  the  adjacent  teeth.  Clean  the  gold.  Build 
up  a  top  and  lateral  contour  with  casting  wax ; 
this  is  readily  done  by  having  the  wax  melted 
ui  a  little  dish,  and  applying  it  with  a  fine 
camel's-hair  brush.  Close  the  bite  on  it,  and 
so  get  a  mould  of  the  occlusal  surface.  Trim 
and  carve  and  poHsli  to  the  correct  shape  of  a 
perfect  tooth  model.  (The  oil  is  applied  to 
prevent  the  wax  from  sticking  to  the  model.) 

The  adjohiing  teeth  may  now  be  broken 
away,  leaving  the  cro^«i-niodel  standing  alone. 
Paint  the  approximal  surfaces  with  a  thin 
layer  of  wax,  to  ensure  correct  approximal 
contact  after  finishing  the  gold;  if  this  is  not 


571 


clone  the  crow-n  might  prove  a  Httle  too  small 
approximally ;  it  is  better  to  have  too  much 
than  too  little.  The  more  smoothly  the  model 
is  finished  and  polished,  the  better  the  cast  will 
be.  The  model  can  then  be  sa-ivn  off  from  the 
plaster.  Attach  a  sprue,  invest  and  pressure- 
cast  with  22-carat  gold.  The  molten  gold  takes 
the  place  of  the  wax  and  adlieres  to  the  shell. 

This  makes  a  very  strong  crown,  and  one 
that  is  very  suitable  for  bridge  abutments  or 
piers,  and  is  much  less  likely  to  give  way  under 
stress  than  the  old  form  of  shell  crown  made 
from  plate.  It  is  not  likely  to  spring  or  yield, 
and  the  method  secures  a  lietter  fit  (17). 

Enamelling  a  Shell  Crown. — An  all-metal 
crown  can  be  enamelled  with  porcelain  and  so 
made  to  resemble  closely  a  natural  tooth.  This 
presupposes  that  the  sheU  is  made  of  platinum, 
and  all  soldering  done  with  platinum  solder  or 
jjure  gold. 

Technique  for  Preparing  the  Root  and  Making 
the  Shell. — Prepare  the  root  or  remauis  of  the 
natural  crown  by  cutting  it  do\TO  sufficiently 
to  allow  the  layer  of  porcelain  to  be  added  to 
the  shell. 

Make  the  shell  as  small  as  possible  -s^ith  the 
same  end  m  view,  i.  e.  to  allow  the  porcelain 
to  be  added  without  unduly  interfering  with 
the  bite,  or  making  the  crown  so  large  as  to  be 
unsightly. 

The  shell  being  complete,  provision  must  be 
made  for  the  secure  attachment  of  the  porcelain. 
The  mere  fusing  of  a  layer  of  porcelain  over  the 
surface  of  the  platmum  would  be  quite  futile — 
owing  to  the  feeble  adliesion  of  porcelain  to 
platinum  it  would  flake  ofi  at  the  earliest 
opportunity ;     nor    would    it    be    sufficient    to 


A.  Platinum  shell  with  wavy  lengths  of  platinum  wire 

soldered  to  it  so  as  to  form  free  loops. 

B.  The  same  indicating  the  coating  of  porcelain  to  be 

fixed  upon  it. 

C.  The  same,  but  with  platinum  wire  gauze  instead  of 

lengths  of  wire. 

roughen  the  platinum  by  merely  jagging  or 
scoring  the  surface.  The  writer's  experiments 
have  satisfied  him  that  the  only  way  to  ensure 
attachment  of  a  sufficiently  satisfactory  kind  is 
to  solder  numerous  fine  platinum  wires,  as 
gauze  or  in  loops,  all  over  the  surfaces  to  be 
enamelled,  so  that  a  large  proportion  of  the 
wires  can  be  completely  embedded  in  the 
substance  of  the  porcelain. 

Technique  for  Adding  the  Wire  :  First  Method. 


Take  platinum  wire  gauze.  Apply  it  to  the 
surface  to  be  enamelled.  Solder  it  to  the 
shell  with  numerous  small  pieces  of  platmum 
solder  (see  Fig.  704,  C).  The  pieces  of  solder 
should  be  distributed  in  a  circle  near  the 
edges  of  the  .surface,  and  also  at  isolated 
spots  withm  the  circle.  Take  care  to  attach 
the  gauze  strongly  and  regularly  without  fill- 
ing up  the  meshes  very  much,   leaving  many 


Fig.   705. 
(S.  S.  White  Dental  Manufacturing  Co.) 

loops  that  can  after\\ards  be  slightly  raised 
from  the  surface  of  the  shell.  Take  a  fine 
pointed  excavator,  and  raise  loops,  which  can 
become  entnely  embedded  in  the  porcelain. 

Second  Metliod. — Take  very  fine  platmum 
wire.  Kink  it  by  windmg  it  tightly  round  a 
small  three-sided  manch-el.  Unwind  it  and 
apply  it ;  its  loops  should  stand  out  at  right 
angles  to  the  surface  to  be  enamelled,  in  lengths 
across  that  surface.  Solder  it  dowii  at  its 
points  of  contact  with  small  pieces  of  solder, 
taking  care  as  before  not  to  fill  up  the  little 
loops  of  wire,  which  are  intended  to  stand  clear 
from  the  surface  (see  Fig.  704,  A).  A  wire  en- 
tanglement, made  properly  by  either  of  these 
two  methods,  will  effectually  hold  the  porcelain 
in  spite  of  the  strain  of  mastication. 

Cap  Crowns  Porcelain-faced. — There  are  several 
methods  of  making  a  cap  crown  porcelain- 
faced,  but  all  require  the  natural  tooth  to 
be  removed  to  some  extent  on  the  labial  or 
buccal  side  to  make  room  for  the  porcelam. 

First  Method.— M&\ie.  a  gold  cap  crown  in 
the  ordinary  way.  Cut  out  a  window  on  the 
labial  side  to  correspond  with  the  proposed 
porcelain  face. 


572 


Take  an  ordinary  flat  tooth,  fit  it  to  the 
window,  clianifer  it  off  on  its  back  surface  at 
both  cervical  and  occlusal  ends,  and  back  it 
with  pure  gold  all  over  the  back  and  chamfered 
surfaces.  Burnish  the  back  close  at  the  edges. 
Place  the  tooth  in  the  window,  invest  and  solder 
it  in  from  the  inside.  The  soldering  can  be 
done  by  ^Tapping  a  strip  of  asbestos  paper 
round  the  whole  of  the  work,  and  attaching  it 
with  binding  wire,  and  then  holding  the  cro^n 
face  downwards,  \\ith  pieces  of  solder  in  position 
on  the  inside,  in  a  Bunsen  flame. 


/  \ ,■ 


Fig.   706. — Shows  teeth  worn  down  and  dotted  lines 
to  show  their  original  sizes. 

Second  MetJiod. — By  fusing  in  porcelam  body. 
Make  a  platinum  cap  crowii  with  its  labial  or 
buccal  side  bulged  inwards  as  far  as  possible, 
and  with  the  top  projectmg  clear  to  form  a 
ledge.  Strengthen  this  ledge  by  soldering  on 
extra  thicknesses  of  hard  platinum.  Solder 
a  strip  of  jilatinum  bent  round  and  forming 
with  the  ledge  a  shallow  cell.  The  cell  is  to  be 
of  the  same  area  as  the  porcelain  is  desired  to 
be.  Solder  a  few  wire  loops  at  the  bottom  of 
the   cell.     Make   the  porcelain   face   by   filling 


times  met  with,  when  it  is  required  to  improve 
their  appearance  without  killing  the  pulp. 
These  crowns  are  closely  akin  to  the  enamelled 
shell  crown. 

Ordinary  Jacket  Crown. — This  is  produced 
by  making  a  gold  or  platinum  cap  to  fit  the 
natural  crowii  very  closely,  and  then  soldering 
to  its  exterior  a  thin-backed  flat  tooth.  The 
crowai  when  finished  is  fixed  on  the  natural 
crowii  with  cement. 

The  Coiled  Wire  and  Fused  Porcelain  Jacket 
Croivn  (Baldwin).- — The  wTiter  has  invented  a 
jacket  crowii  which  in  his  hands  has  been  very 


Fig.  707. — Sagittal  section  of  tooth,  and  the  dotted 
line  shows  tlie  part  worn  away.  The  dark  lines 
show  the  amount  that  must  be  ground  away. 

up  the  cell  with  successive  layers  of  porcelain 
body  and  baking  in  the  furnace. 

This  method  is  very  applicable  to  the  front 
teeth  in  those  difficult  cases  where  the  teeth 
have  been  very  much  worn  down  by  masti- 
cation, but  the  pulps  not  invaded,  and  it  is 
desired  to  raise  the  bite  and  prevent  further 
rearing  down  by  cro\TOing. 

Jacket  Crowns.  —  These  hollow  crowns  with 
an  enamelled  face  or  enamelled  exterior  are 
made  to  fit  over  the  whole  of  the  natural  crown 
of  the  tooth,  or  the  natural  crown  but  very 
slightly  modified  in  shape  by  grinding.  They 
are  designed  for  covering  "  live  "  teeth,  especially 
the  small  feline -looking  lateral  incisors  some- 


A  B 

Fig.   708. 

A.  "  Feline  "    lateral    incisor    to    be    covered   with    a 

jacket  crown. 

B.  Jacket  crown  fixed. 

successful,  having   stood   the   test  of    wear   in 
the  mouth  for  many  years. 

The  case  for  which  it  was  origmally  designed 
WHS  a  left  upper  lateral  incisor.  The  crown  of 
the  tooth  was  of  the  weU-knowai  cat's-tooth 
variety,  being  a  small  simple  cone  with  a 
space  on  each  side  of  it  separating  it  from  the 
adjacent  teeth.  The  tooth  was  decidedly  dis- 
figuring, and  the  patient,  a  lady,  was  anxious 
to  have  its  appearance  improved.  The  writer 
decided  not  to  cut  down  the  natural  cro^^•n  or 
to  kill  the  pulp,  on  account  of  the  extreme 
smallness  and  delicacy  of  the  tooth  (see  Fig.  708). 


B      C 

Fig.   709. 

A.  Platinum  wire  coil. 

B.  Flake  of  porcelain. 

C.  Flake    in    place    ready    for    fixing    with    porcelain 

body. 

Technique  (see  Fig.  709). — Take  a  plaster 
impression  in  an  ordinary  crown  tray.  Pack 
the  impression  of  the  tooth  with  Sullivan's 
amalgam,  and  cast  the  rest  with  plaster. 

Wlien  set,  wrap  one  layer  of  thin  soft  platinum 
foil  round  the  tooth  in  the  form  of  a  close- 
fitting  cone.  Make  a  coil  of  thin  platinum  wire 
tightly  wrapped  on  the  model,  over  the  cone  of 
foil  from  base  to  summit.  Remove  the  cone 
and  coil  together  from  the  model,  and  tack  its 
parts  together  with  small  pieces  of  pure  gold  or 
platinum  solder.  Place  the  solder  in  front  at 
isolated  intervals  so  that  the  coils  of  wire  in  front 


573 


will  not  be  entirely  fused  together ;  but  at  the 
sides  and  back  place  much  more  solder  or  even 
a  strip  of  thin  jJate  soldered  solidly  to  the  cone, 
so  that  the  whole  will  form  a  strong  and  coherent 
structure  and  have  plenty  of  stiffness  and 
strength  at  the  sides  and  back. 

Take  a  flat  tooth  and  grind  it  as  thin  as  a 
thumbnail  to  fit  in  front  of  the  cone  ;  the  process 
of  grinding  to  this  degree  of  tenuity  wUl,  of 
course,  remove  every  trace  of  the  platinum  pins. 
Now  attach  the  flake  in  position  to  the  cone  with 
porcelain  body  and  fuse  it  in  the  furnace ; 
contour  it  at  its  edges  with  porcelain  body  to 
a  nice  finish.  When  commencing  the  aj)plica- 
tion  of  the  porcelain  body  care  must  be  taken 
to  use  it  mixed  thin,  and  to  work  it  and  tap  it 
do\\ai  thoroughly  into  the  meshes  of  the  wire, 
and  also  to  paint  it  w  ell  on  the  back  of  the  porce- 
lain-flake to  ensure  good  union.  No  porcelain 
body  should  be  allo\\ed  to  get  on  the  face  of  the 
flake.  When  finished  fix  with  cement.  Take 
care  the  bite  is  not  heavy  on  it. 

R.  H.  Riethmiiller  and  H.  Hough  (14)  describe 
and  give  detaUs  for  making  The  All-Porcelain 
Jacket  Crown,  which  to  the  present  wTiter 
seems  unjjromising,  both  on  account  of  the  diffi- 
culty of  preventing  shrinkage  altering  the  fit, 
and  also  on  account  of  the  fragility  of  the 
fuiished  work.  The  drastic  stripping  of  a  live 
tooth  of  its  enamel  and  cutting  into  sensitive 
dentine  is  also  undesirable.  Some  of  their 
details,  however,  are  interesting  enough  to  be 
repeated  here. 

Technique. — Measure  circumference  of  the 
tooth  with  wire.  Grind  the  tooth  with  J-inch 
fine  carborundum  stone  up  to  the  gum  on  all 
sides.  If  still  alive,  guard  against  thermal  shock 
[sjc]  by  cool  water,  freely  applied.  Use  also 
a  small  knife-edge  stone.  The  tooth  is  thus 
given  a  peg -shape.  Cut  a  clear  terrace -like  base 
with  an  end-cutting  fLssure-burr  of  fine  cut. 

Take  a  platinum  band  (i^.Vo  hich)  broad 
enough  to  cover  the  peg-shaped  tooth,  and  the 
length  of  the  wire  measurer,  and  solder  the 
ends  together  with  a  pellet  of  pure  gold.  Gently 
force  the  edge  of  the  band  over  the  shoulder 
under  the  gum.  Fix  this  matrix  under  the  gum 
and  over  the  shoulder,  with  a  very  fine  wire 
ligature.  Wmd  floss  silk  round  the  rest  of  the 
matrix  tightly,  and  so  secure  adaptation  of 
matrix  to  tooth.  Burnish  the  matrix  against 
the  shoulder  with  flat  burnisher.  Remove  the 
wire  ligature  and  silk,  and  take  plaster  imjjres- 
sion.  Varnish  the  impression  containing  the 
matrix,  and  cast  in  inlay  investment  to  which 
enough  plaster  is  added  to  cause  it  to  set  in  a 
reasonably  short  time.  Separate  the  impression 
from  the  model  and  matrix.  Cut  away  the 
plaster  teeth  on  each  side  to  allow  for  shrinkage 
of  porcelain. 

Build  up  high-fusing  porcelain  body  on  the 


matrix.  BuUd  up  one-sixth  larger  than  re- 
quu-ed  ■\\ith  high-fusing  body  of  correct  shade, 
and  finish  to  correct  shape.  The  furnace  must 
have  a  pyrometer.  Raise  the  temperature  to 
1800°  or  1900°  F.  Dry  the  work  at  the  mouth 
of  the  furnace  for  five  minutes.  Introduce  it 
into  the  furnace  gradually  on  a  fireclay  slab 
sprmkled  with  coarse  sUex.  Close  the  door  of 
the  furnace.  Within  eight  minutes  gradually 
raise  the  temperature  to  2200°  F. ;  then  gradu- 
ally turn  do\vn  switch  to  0.  Oj^en  the  door 
and  when  the  heat  has  abated  to  about  1800°  F. 
and  the  shrinkage  has  taken  place,  remove  from 
the  furnace  and  allow  to  cool.  If  defects, 
checks,  or  uneven  shrinkage  are  noticed,  fill 
with  more  porcelaui  body  and  bake  again  for 
ten  mmutes,  gradually  raising  to  2300°  F.,  and 
taking  care  not  to  exceed  this,   which  is  the 


Fig.   710. — Leon  Williams's  Porcelain  Crowns. 

{Dental  Manufacturing  Co.,  Ltd.) 

fusing  point.  At  once  turn  down  to  0,  and 
allow  the  temperature  to  drop  to  2100°  F.  Open 
the  door  of  the  furnace  slightly.  Leave  the 
work  in  half-closed  furnace  for  five  more 
minutes.  Remove  from  the  furnace  and  cover 
with  a  tin  can  to  protect  from  draughts. 

Wlien  cool,  remove  the  plaster  core  and  also 
the  platinum  matrix ;  this  is  not  difficult,  as 
the  edge  of  the  platinum  projects  beyond  the 
cervical  edge  of  the  porcelain.  The  crown  is  now 
complete.  Fix  with  Harvard  inlay-cement 
mixed  thin. 

Ready-made  Porcelain  Molar  and  Premolar 
Crowns. — The  Bonwill  porcelain  molar  and 
premolar  crown  is  the  original  type  of  these,  and 
later  ones  are  merely  varieties. 

It  consists  of  a  mass  of  porcelain  hollo^^•ed 
out  in  the  middle  by  a  large  cavity  running 
vertically  right  through  it,  and  deeply  counter- 
sunk at  both  radical  and  occlusal  ends.  It  is 
fitted  by  grinding,  as  well  as  may  be,  to  the  root. 


574 


Posts  are  fixed  in  the  various  roots,  bent  in 
such  directions  as  to  allow  theiu  to  pass  through 
the  cavity  in  the  crown.  Then  the  crown  is 
fixed  with  cement  or  amalgam,  or,  better  still, 
with  a  combination  of  the  two  (PcA). 

The  Leon  Williams  porcelam  molar  is  similar 
to  the  Bonwill,  differing  only  in  shape,  and  in  the 
shape  of  the  cavity  that  runs  through  the  cro^vai. 

The  objection  to  this  type  of  crown  is  its 
inherent  weakness,  caused  by  the  large  size  of 
the  hollow  that  is  necessitated  by  having  to 
provide  for  the  passage  of  the  posts. 

Making  a  Porcelain  Crown  for  an  Upper 
Molar. — This  is  the  most  difficult  problem  to 
solve  in  the  -v^hole  art  of  crowning,  i.  e.  if 
the  rules  laid  down  on  p.  553,  that  each  root 
of  a  crowned  tooth  shall  be  provided  with 
a  post,  and  that  the  post  shall  fit  the  whole 
length,  as  far  as  possible,  of  a  concentrically 
enlarged  root-canal.  The  problem  consists  in 
providmg  a  crown  that  shall  be  sufficiently 
strong  in  itself,  and  also  sufficiently  strongly 
attached  to  the  root. 

The  strength  of  the  porcelain  crown  itself 
will  depend  largely  on  its  mass  ;  the  greater  the 
thickness,  the  greater  the  strength.  To  admit 
a  sufficient  thickness  the  whole  of  the  remams 
of  the  natural  cro^^•n  must  be  amputated  flat  at 
the  gum  level. 

The  difficulty  of  attachmg  it  sufficiently 
strongly  depends  on  the  divergence  of  the 
roots.  The  roots  are  generally  so  divergent 
that  it  would  be  impossible  to  insert  the  crown 
if  three,  or  even  two,  good  long  posts  were 
already  attached  to  it ;  unless  either  very  much 
of  the  posts  were  to  be  abandoned,  or  very  much 
valuable  root-substance  sacrificed,  (1)  some  of 
the  posts  must  be  fixed  in  the  roots  fust  inde- 
pendently of  the  crown,  or  (2)  some  of  them 
must  be  passed  right  through  the  crown  and 
into  the  roots  after  the  cro\vn  is  fixed. 

Method  I  (a) . — For  cases  where  the  bite  is  not 
too  close.  First  fix  all  the  three  posts  in  the 
roots.  The  posts  must  have  been  j^reviously 
bent  so  that  their  projecting  ends  will  stand 
fairly  close  together  and  fairly  parallel  to  each 
other,  together  forming  a  column. 

Take  an  accurate  impression  of  the  root  and 
adjoining  teeth,  and  a  bite  in  a  Rhodes's  tray, 
and  cast  the  root  ^^•ith  amalgana  (p.  557). 
In  order  to  prevent  the  posts  from  distorting 
the  impression  build  a  little  oxy-sulphate  of 
zinc  (Fletcher's  artificial  dentine)  round  them, 
and  so  form  the  whole  of  the  three  posts  into 
a  slightly  conical  pillar,  M-hich  when  set  must 
be  soaped.  This  will  allow  the  impression  to 
be  taken  off  the  root  without  dragging. 

Making  the  Crown  to  the  Model. — Take  a  strip 
of  platinum.  No.  4.  Bend  it  round  to  form  a 
barrel  to  fit  loosely  round  the  column  represent- 
ing the  posts.     Solder  its  edges  with  platinum 


Fig.  711. 


solder.  Make  a  diaphragm  of  No.  2  soft 
platinum  to  cover  the  root.  Solder  the  end  of 
the  barrel  to  the  centre  of  the  diaplu-agm.  Cut 
away  the  diapliragm  where  it  closes 
the  end  of  the  barrel.  Place  on  the 
root  and  burnish  down  the  diaphragm 
into  an  accurate  fit  on  the  root.  Close 
the  free  end  of  the  barrel  with  platuium 
plate  flush  with  the  ends  of  the  posts.  Wrap 
round  the  barrel  six  or  eight  coils  of  fuie  pla- 
tinum wire  fireviously  kinked,  and  so  form  a 
number  of  outstandmg  loops  to  be  subsequently 
embedded  in  the  porcelain.  Solder  these  firmly 
to  both  tube  and  diaphragm,  takmg  care  not  to 
obliterate  the  loops.  This  soldermg  process 
will  warp  the  work  slightly;  therefore,  return 
it  to  the  model  and  refit  the  edges  of  the  dia- 
phragm by  pressure  and  burnishing. 

Adding  the  Porcelain. — Mix  high-fusing  porce- 
lain body  thin,  and  thoroughly  work  it  into  all 
the  loops  and  round  the  central  barrel,  and  fuse. 

Cut  a  thin  flake  of  porcelaui  from  a  porcelain 
molar  and  fit  it  to  form  the  buccal  surface. 
Attach  it  by  packing  porcelain  body  between 
it  and  the  barrel.  Place  it  (porcelain  flake 
uppermost)  in  the  furnace,  and  fuse. 
By  successive  fusings  (and  intermediate 
grinding,  if  necessary)  buUd  up  all  the 
rest  of  the  crown  with  porcelain  body. 
Adjust  to  the  bite.  If  necessary  grind 
the  buccal  flake  still  thinner  and  repolish.  Wlien 
finished  fix  in  the  mouth  with  oxy-phosphate 
cement. 

Method  I  {b). — For  close  bites.  Fix  the  three 
posts  m  the  root  in  the  mouth  as  before,  but  let 
them  project  as  much  as  the  bite  will  aUow. 

Make  a  crown  exactly  as  in  Method  II,  but 
when  fniished  grind  away  the  masticating 
surface  and  platinum  closing  the  end  of  the 
barrel,  and  so  establish  a  passage  for  the  posts 
right  thi'ough  the  crown.  Fix  this  in  the 
mouth  with  PcA. 

MetJiod  II. — This  method  of  the  writer's 
the  really  complete  solution  of  the  problem. 

Prepare  all  three  canals  for  taper  posts. 

Make  three  posts  from  pm-size  wire,  tapering 


Fig 


is 


Fig.  713. 


-Stump  of  upper  molar  with  three 
divergent  roots. 


the  part  only  that  will  enter  the  canals,  and  let 
them  be  longer  than  the  bite  will  allow. 

Make  a  platinum  diaphragm  to  cover  the  root- 


575 


face.  Pass  the  plus  through  holes  in  the  dia- 
pliragm  into  their  places  in  the  canals,  and  it 
■will  probably  be  found  that  two  of  the  free 
ends  of  the  pins  will  interfere  with  each  other. 
Remove  the  two  that  do  not  interfere  with  each 
other,  and  stick  the  remainuig  one  to  the 
diapliragm  with  sticky  wax. 

Remove  from  the  mouth  and  solder  this  one 
pin  to  the  diaphragm  in  its  correct  position  with 


Fig.  714. — Platinum  diapliragm  with  one  platinum 
post  soldered  to  it. 

platinum  solder.  Cut  off  some  of  the  free  end 
of  this  pin,  and  also  bend  it  a\\ ay  sufficiently  to 
allow  the  other  two  jjins  to  be  passed  through 
the  diaphragm  easily  into  their  respective  holes 
in  the  roots,  and  to  make  it  very  free  from  the 
bite. 

Now  take  the  impression.  Use  the  dia- 
phragm and  smgle  soldered  pin  as  a  support 
for  a  core  impression  of  the  root  taken  with  a 
little  Hill's  gutta-percha.  Over  the  core  im- 
pression take  a  plaster  or  composition  impres- 
sion, and  a  bite,  in  a  Rhodes's  crown  tray.  Cast 
an  amalgam  model  of  the  root-face  in  conjunc- 
tion with  a  plaster  cast  of  the  rest,  and  also  a 
bite,  in  the  manner  detailed  on  p.  557. 

To  thLs  model  thoroughly  fit  the  diaphragm. 
Try  in   the   mouth.     Pass   the  remaining  two 


Fig.  715. — Pin-size  platinum  tubes  correctly  aligned 
by  having  loosely  fitting  pins  thrust  through  them 
and  through  the  diapliragm  in  place  on  the  root. 
The  tubes  are  secured  to  the  work  with  wax,  and 
the  pins  withdrawn. 

taper  pins  through  the  diaphragm  into  their 
respective  canals.  Over  each  of  these  two  pass  a 
platinum  tube,  such  as  is  used  in  the  manufac- 
ture of  Ash's  tube-teeth  and  can  be  purchased 
from  Messrs.  Ash.  Stick  the  tubes  to  the  dia- 
phragm with  sticky  wax.  Withdraw  the  two 
pins  without  disturbing  the  tubes.  Remove  the 
rest  of  the  work  from  the  mouth,  invest,  and 


solder  the  tubes  with  platinum  solder  to  the 
diajohragm.  Try  m  the  mouth,  and  try  in  the 
removable  pins  through  their  resjiective  tubes 
into  their  respective  canals. 

Again    remove    from    the    mouth,    first    the 
sliding  pins,  then  the  rest  of  the  work.     Xow 


Fig.  716. — Platinum  diaphragm  with  two  platiniun 
tubes  and  one  platinum  pin  soldered  to  it. 

solder  a  platinum  wire  entanglement  (as  on 
p.  571)  securely  to  both  tubes  and  diaphragm. 
Make  a  buccal  flake  of  porcelain  by  grindmg 
from  a  porcelain  molar.  Place  this  in  position, 
and  fix  it  with  porcelain  body,  and  fuse  it  on. 
Now  build  up  the  remamder  of  the  crowTi  with 
successive  fusings  of  porcelain  body,  taking  care 
to  prevent  it  getting  inside  the  tubes  by  filling 
them  first  with  powdered  silica. 

By  dint  of  successive  additions  of  porcelain 
body  and  intermediate  trimmings  by  grinding. 


Fig.  717. — Porcelain  tooth 
fused  round  the  platinum 
structure. 


FiG.718. — Crown  cemented 
on.  The  root-pins  are 
tlirust  tlirough  while  the 
cement  is  still  soft. 


a  good  porcelain  molar  can  be  built  up,  and  the 
external  buccal  flake  can  be  ground  on  the  face 
if  necessary,  and  rejiolished. 

Wlien  finished,  the  crown  is  to  be  fixed  m 
the  mouth  with  oxy-phosphate  cement.  It 
must  be  cemented  and  pressed  home  fiist  with- 
out its  removable  jjins,  and  then  innuediately 
while  the  cement  is  stUl  soft  its  removable  pins 
(also  smeared  with  cement)  must  be  run  through 
their  tubes  and  jammed  home  into  their  respect- 
ive canals.  When  set,  grind  off  the  surplus 
length  of  the  two  pins  to  fit  the  bite. 

Cast  Gold  Base. — George  Northcroft  solves 
the  porcelain  molar  problem  by  being  content  to 
reduce  the  buccal  pins  to  very  smaU  size,  re- 
lying chiefly  on  one  good  post  in  the  palatine 


576 


root.  He  uses  taper  wire  to  fit  the  enlarged 
palatine  canal,  thrusts  this  through  a  wax 
diaphragm  (for  reproduction  in  gold)  on  the  root, 
and  presses  the  wax  into  the  buccal  roots  to  form 
"  cast  gold  buccal  pins  ",  but  so  short  that  the 
divergence  of  the  roots  Is  no  hindrance.  To  thLs 
cast  gold  base  lie  fixes  a  tube-tooth  or  a  dowel 
molar  crown. 

In  such  a  case  a  diatoric  tooth  could  be  used 
in  the  mamier  mentioned  by  T.  E.  Weekes  (18). 
Grind  out  the  countersink  with  a  small  barrel- 
shaped  carborundum  point  (S.S.W.,  No.  13). 
Grind  both  approximal  surfaces  of  the  tooth  tUl 
parallel,  and  also  the  lingual  surface.  Coat  the 
tooth  with  vaseline.  Mould  casting  wax  upon 
it  until  buUt  up  to  proper  form.  This  would 
then  be  pressed  into  place  upon  the  wax  dia- 
phragm on  the  root,  chilled,  trimmed,  and 
removed  from  the  mouth ;  the  porcelain  would 
be  removed  from  the  wax,  a  sprue  attached  to 
the  labial  free  edge,  and  the  crown  pressure-cast. 
Into  the  partial  cap,  and  on  to  the  tenon  so 
formed,  the  porcelain  would  be  cemented.  In 
this  case  the  gold-casting  could  not  be  done 
direct  to  the  porcelaui,  because  the  shrinkage 
of  the  gold,  on  cooling,  being  outside,  would 
crack  the  porcelain. 

To  Crown  a  Very  Badly  Carious  Molar. — When 
a  tooth  is  very  badly  carious  below  the  gum, 
some  of  its  roots  perhaps  being  represented 
by  a  mere  tube  of  cementum  as  to  part  of  their 
length,  the  proper  plan  is  first  to  fix  into  each 
root  a  post  that  will  in  each  case  go  as  near  to 
the  apex  of  the  root  as  possible,  and  to  fix  it  as 
strongly  as  possible.  This  having  been  done, 
the  crown,  m  the  form  of  a  metallic  matrix  or 
band,  is  to  be  placed  in  position  around  or  on 
the  edge  of  the  root,  and  filled  with  PcA ;  or 
with  amalgam  alone,  if  moisture  cannot  be 
entirely  excluded.  This  matrix-band  can  be 
shaped  so  as  to  fulfil  all  requirements  as  to 
contour  and  occlusion,  or  it  can  be  arranged  so 
as  to  be  smaller  in  all  dimensions  and  parallel- 
sided,  when  it  can  be  covered  over  by  an 
ordinary  gold  shell  crown  or  a  porcelain  crown 
mounted  on  a  cap. 

Technique. — After  properly  exposing  the  root, 
as  described  on  p.  552,  and  thoroughly  removing 
all  caries  and  softened  tooth-substance,  espe- 
cially at  the  absolute  edges,  enlarge  the  root- 
canals  to  take  the  taper  posts  to  the  extreme 
ends  if  possible,  just  short  of  perforation.  Seal 
the  ends  of  the  canals  with  a  minute  plug  of 
cotton-fibre  wrapped  on  the  end  of  a  Donaldson 
bristle  and  dipped  in  chloro-percha  plus  a  solid 
antiseptic  in  powder,  such  as  chinosol,  paraform, 
or  hydronaphthol. 

Select  taper  posts  that  will,  when  ui  place, 
project  well  beyond  the  edges  of  the  root,  but 
be  short  of  the  bite,  and  secure  them  as  strongly 
as  possible  with  cement.     If  for  any  reason  it 


is  impossible  to  get  a  good  hold  for  more  than 
one  post,  this  post  should  be  a  screw-post,  and 
should  be  fitted  into  a  hole  previously  tapped. 
In  this  case  a  cylindrical  screw  post  is  used,  not 
a  taper.  A  How's  screw-post  and  How's  taps 
wiU  answer  very  well.  The  post  should  have 
one  side  filed  flat,  or  a  longitudinal  groove 
cut  on  one  side.  Before  screwmg  it  home, 
the  hole  and  the  post  should  be  smeared  with 
thin  cement  or  thick  chloro-percha,  so  that  the 
joint  between  the  screw  and  the  dentine  may 
be  watertight,  and  no  interstices  left.  The  object 
of  flattening  and  grooving  one  side  of  the 
screw  is  to  provide  a  means  of  escape  for  the 
surplus  cementing  material,  which  might  other- 
wise be  forced  by  the  advance  of  the  screw 
through  the  apical  foramen. 

The  screwed-in  post  gives  a  much  stronger 
attachment  for  a  single  post  than  a  smooth 
post  cemented  (7),  but  in  an  upper  molar, 
where  multiple  posts  can  be  provided  entermg 
their  holes  to  a  good  depth  and  yet  diver- 
gent, simple  well-fitting  taper  posts  are  sufii- 
cient.  Where  the  roots  are  not  too  divergent, 
Norman  G.  Bemiett  solders  their  free  ends 
together  before  fixing  them  wdth  cement,  and 
in  this  case  the  posts  should  be  made  of  very  soft 
wire,  so  that  they  are  capable  of  spreading 
apart  a  little  if  necessary  while  being  forced 
finally  home. 

Havmg  fixed  the  posts,  make  a  gold  or 
platinum  band  direct  to  the  mouth,  just  reaching 
the  bite,  contoured,  and  wired  on  the  inner  side 
of  the  occlusal  edge  (for  all  details  see  p.  559). 

Fix  this  with  PcA,  or,  if  impossible  to  exclude 
all  moisture,  with  amalgam  alone.  During  this 
process,  if  there  is  trouble  from  oozing  from  the 
gum  or  periodontal  membrane,  touch  the  gum 
edge  or  source  of  the  oozmg  with  Merck's  per- 
hydrol,  full  strength.  This  is  the  best  remedy 
for  oozing  kno\\n  to  the  wTiter,  and  is  a  method 
for  which  he  is  indebted  to  William  Hern. 
(For  details  of  the  fixing  and  the  amalgam 
to  be  used  see  pp.  561,  598.)  In  order  to  se- 
cure the  advantages  of  the  foregomg  method 
with  the  provision  of  a  highly  finished  all-gold 
crown  the  writer's  method  is  as  follows — 

After  fixing  the  posts  make  a  thin  huier  band 
or  matrix  of  gold,  platinum,  or  dental  alloy, 
direct  to  the  root,  fitted  accurately  to  all  the 
sinuosities  of  its  edge  (for  details  see  p.  562), 
but  well  short  of  the  bite.  Do  not  contour  the 
sides,  but  leave  them  parallel.  Fix  this  on  the 
root  with  pink  wax.  Take  a  bite  with  a  small 
mass  of  j)laster  of  Paris  on  the  end  of  the  band 
and  wax.  Remove  the  bite.  Take  an  impres- 
sion in  composition  in  a  crown  tray,  or,  better 
still,  take  both  bite  and  impression  simultane- 
ously in  a  Rhodes 's  crown  tray.  Remove  from 
the  mouth,  and  fit  the  inner  matrix  into  its  bed 


577 


in  the  impression  and  wax  it  there.  To  the 
resulting  model  the  mechanic  will  now  make  a 
gold  crown  weW  contoured  and  fitting  the  inner 


Fig.  719. — Method  of  crowning  a  buried  molar  root. 
A  carefully  fitted  inner  matrix  crown  of  small 
size  is  fixed  with  amalgam.  Over  this  an  ordinary 
gold  cap  crown  is  fixed. 

drum  tightly  at  its  cervical  edge,  but  wiU  not 
at  present  solder  on  the  top.  Now  try  in  the 
mouth    the    three    parts    waxed    together    and 


as  in  the  preceding  method.  The  wax  is  then 
to  be  softened  by  heat,  and  the  outer  shell 
removed  and  sent  to  the  workroom  for  the 
mechanic  to  solder  on  the  top  and  finish  the 
crown  (see  Fig.  719).  When  finished,  fix  the 
crowia  over  the  inner  drum  on  the  root  with 
cement. 

The  object  in  leaving  the  top  of  tlie  outer 
shell  open,  and  having  its  band  around  the  inner 
drum  while  packmg  the  fillmg,  is  that  the  mner 
drum  may  not  be  pushed  by  the  packing  out  of 
its  proper. position,  as  it  would  very  likely  be 
if  this  precaution  were  not  adopted,  with  the 
result  that  the  outer  shell  might  not  go  on  at 
all. 

Tliis  method  of  crowning  combines  the 
advantages  of  a  highly  finished  closed  crown 


(D  (D  (D 
12 


m 


Fifi.  720. — Screw-post  Appliances  for  Crowns. 

{S.  S.  White  Dental  Manufacturing  Co.) 


1. 

Mandrel  or  holder. 

7. 

For  right-angle. 

2_ 

Screw-driver. 

8. 

Screw-posts  (How's). 

3. 

Sleeve  to  hold  screw  steady. 

9. 

Nut-driving  tools. 

4. 

Screw-driver,   sleeve,    and   screw 

10. 

Short  mandrels. 

in  place. 

11. 

Short  hub  for  riglit-angle  tool 

5. 

Twist-drills  for  drilling  parallel- 

12. 

Nuts. 

sided  holes. 

13. 

Headed  screws. 

6. 

Taps. 

fuially  adjust  the  bite.  Then  remove  the  top, 
and  whUe  the  inner  and  outer  bands  are  still 
waxed  together,  fix  the  inner  to  the  root  and 
posts  by  packing  full  of  PcA  or  amalgam  alone, 
19 


with  those  of  an  open  matrix-crown  fixed  by 
packing  amalgam  or  PcA  directly  on  the 
root  and  round  the  posts  through  its  open 
end. 


578 


To  Crown  a  Very  Badly  Carious  Incisor,  Canine, 
or  Second  Upper  Premolar  or  Lower  Premolar. 
Sometimes  a  crown  may  be  of  sucli  great 
advantage  to  a  patient  that  very  badly  carious 
and  unpromising  roots  are  justifiably  crowned, 
and  sj)ecial  methods  are  necessary  for  those 
cases  in  which,  to  use  Norman  G.  Bennett's 
words,  "  the  root  has  a  liealtliy  periodontal 
membrane,  but  is  softened  by  decalcification  of 
dentine  for  half  or  three-quarters  of  its  length, 
i.  e.  is  not  much  better  than  a  shell  of  cementum, 
with  a  small  portion  of  the  apex  left,  and  the 
edge  more  or  less  eroded  beyond  the  gum 
margin." 

Here  no  coUar  is  possible.  The  jjost  must 
be  fixed  as  far  as  jjossible  into  the  apex  of  the 
root.  A  screw -cut  post,  such  as  Hows,  screwed 
into  a  carefully  tapped  hole  in  the  root  is  the 
best  way  (see  Fig.  720).  Norman  G.  Bennett 
says  "  the  only  way ",  and  the  principle  has 
been  endorsed  by  How,  Weston,  St.  George 
Elliott,  Bonwill,  Walter  Coffin,  and  Leonard 
Matheson.  Norman  G.  Bennett  regards  I  or 
even  ^  inch  of  sound  apex  sufficient.  He 
does  not  seal  the  apical  foramen  becau.se  of 
diminishing  by  so  small  an  amount  the 
available  length.  Where  there  is  no  obvious 
passage  through  to  the  periodontal  membrane, 
as  determmed  by  probing  with  a  Donaldson 
bristle,  this  is  unnecessary.  Tap  the  hole,  and 
screw  in  the  post  smeared  «ith  cement  or 
chloro-f)ercha  ;  then  fill  up  the  liollow  in  the 
root  round  the  post  with  PCA.  After  a  day 
has  elapsed  fit  to  tlie  amalgam  surface  a  dowel 
crown,  or  detached-pin  porcelain  crown,  over 
the  projecting  end  of  the  screw.  If  the  bite 
is  too  close  for  these,  pass  over  the  post  a 
piece  of  platinum  tube.  Pass  a  piece  of  plati- 
num foU  over  the  tube  to  form  a  diaphragm. 
Fit  this  to  the  built-up  root ;  solder  together. 
Fuie-fit  in  mouth  after  soldering.  To  this  fit 
and  solder  a  backed  flat  tooth,  and  make  up 
the  contour  at  the  back  by  adding  pieces  of  wii'e 
or  plate  and  solder.  Fix  this,  when  finished, 
in  the  mouth  with  oxy-phosphate  (5)  (7). 

W.  Rushton  says,  in  those  cases  where  an  old 
crown  has  come  out  and  the  root  is  found  much 
hollowed  by  caries,  "  first  carefully  clean  and 
polish  the  crown,  clear  out  all  vestiges  of  caries, 
pack  unvulcanized  rubber  round  the  pin,  and 
force  the  whole  into  the  root.  After  a  little 
while  remove  it.  Vulcanize.  Adjust  to  a  fine 
fit  and  cement  it  in." 

E.  B.  Dowsett  recommends  packing  with 
PcA  round  a  central  rod  of  wood  or  gutta- 
percha. Wlien  set  he  drills  out  the  wood  or 
gutta-percha  and  makes  a  crown  with  a  fixed 
post.  This  is  because  he  thinks  that  tlie  crown 
separate  from  the  pin  will  come  off. 

T.  A.  Coysh  recommends  the  metal  tube  fixed 
in  the  root. 


Ready-made  Porcelain  Crowns 

( 1 )  With  Fixed  Posts. — Logan  crowns . 

(2)  With    Detachable    Posts. — Davis    crowns, 

Ash's  dowel  crowns,  Robbins's  crowns, 
Newland-Pedley  crowns. 

1.  With  Fixed  Posts. — The  Logan  Crown. 
These  crow  ns  ha\'e  an  H  -section  platinum  taper 
post  baked  into  them.  This  form  of  post  gives 
probably  the  maximum  strength  of  post  for  a 
given  weight  of  platinum,  but  it  does  not  allow 


Fig.  721. — (1)  Enlarged  sectional  view  of  incisor  root 
witli  Logan  crown  in  position,  showing  cup  for 
retaining  materia!.  (2)  Enlarged  incisor  crown  in 
position  fitted  to  root,  whicli  is  cut  away  to 
expose  pin. 

{S.  S.  White  Dental  Manujacturing  Co.) 

of  the  maxinuim  strength  of  combined  post  and 
root,  because  the  root  is  weakened  too  much 
by  the  large  hole  that  must  be  reamed  in  it. 
The  crowns  in  many  cases  match  the  natural 
teeth  very  well  indeed,  and  are  partially  trans- 
lucent and  lifelike,  and  are  in  these  respects 
probably  superior  to  any  other  kind  of  crown. 
They  are,  however,  not  so  strong  as  other 
crowns  described  in  this  work,  and  the  platinum 
post  is  necessarily  very  soft,  owing  to  its  being 


Fig.   722. — Logan  Crown.      Set  of  six  front  upper 
crowns,  natural  size. 
(S.  S.  White  Dental  Manufarturing  Co.) 

thoroughly  annealed  in  the  baking  of  the  tooth. 
They  often  fail  either  by  the  breakmg  of  the 
porcelain,  bendbig  or  breakmg  of  the  post,  or 
breaking  of  tlie  root.  The  breaking  of  the  root 
is  often  induced  by  the  large  amount  of  sound 
substance  that  nuist  be  reamed  out  of  the  root 
to  accommodate  the  post — an  amount  which  is 
considerably  larger  than  would  be  the  case 
for  an  orduiary  taper  pin  (see  Fig.  723).  In 
close  bites  they  are  strongly  contra-mdicated, 
because  when  much  ground  down  their  strength 


579 


is  reduced  below  the  desii-able  ruinimum.  More- 
over, they  are  not  supplied  in  such  great  variety 
of  colour  and  shape  as  the  ordinary  plate  (or 
vulcanite)  tooth,  and,  even  if  matching  well  in 
every  other  respect,  they  ^\ill  frequently  be 
found  not  properly  to  cover  the  face  of  the  root. 
They  are  rather  more  difficult  to  fit  than  similar 
cro«ns  having  detachable  pins.  They  are  suit- 
able only  for  single-rooted  teeth,  as  a  double  or 
bifid  pin  presents  additional  complications  w  hen 


Fig.   723. — Logan   pin,   and   sectional    view   of   Logan 
pin  in  root. 
(iS.  >S.  White  Denial  Manulacturing  Co.) 

the  attempt  is  made  to  secure  a  perfect  fit — diffi- 
culties that  can  only  be  surmounted  by  unduly 
sacrificing  valuable  tooth  substance. 

They  -can  be  fitted  to  the  root  direct  in  the 
mouth  or  to  a  model  in  the  workroom.  In 
either  case  the  sharp  edges  of  the  platinum  pin 
should  first  Ije  removed  with  a  file  to  lessen  the 
necessity  for  making  such  a  very  large  hole  in 
the  root. 


Fig.  724. — Lugan  Crown.  Shows  the  unsnitabihty  of 
a  Logan  Crown  for  a  Ijifid  root.  The  pin  of  the 
Logan  has  been  spht  and  the  two  halves  have 
been  bent  away  from  each  otlier.  To  accommodate 
this  an  excessive  amount  of  root-substance  would 
have  to  be  removed,  and  the  root  lamentably 
weakened. 

(<S'.  <S'.   White  Dental  Maniifacturuig  Co.) 

To  Fit  a  Logan  Crmvn  Direct  to  the  Mouth. 
Technique. — Enlarge  the  root-canal  in  the  rou- 
tine way  (see  p.  549) ;  then  further  enlarge  it 
with  an  Ottolengui's  reamer,  and  make  it  oval  in 
section  by  bearing  on  the  reamer  alternately 
anteriorly  and  posteriorly,  until  it  is  large 
enough  to  admit  the  post. 

Shape  the  face  of  the  root  by  grinding  it  to 
a  simple  form  with  a  wheel,  concaving  it  a  little 
under  the  free  edge  of  the  gum  at  the  labio- 


cervical  edge,  leaving  it,  if  possible,  a  little 
standing  free  of  the  gum  elsewhere,  and  arriving 
as  far  as  possible  at  a  flatfish,  or  even  rather 
domed,  sui'face.  Now  grmd  the  base  of  the 
crown  to  fit  the  root-face  with  a  carborundum 
wheel.  A  thin  steel  disc  mounted  with  the 
wheel  to  form  a  safe  side  to  prevent  injury  to 
the  post  can  be  used,  as  suggested  by  W.  H. 
Dolamore. 

Now  fine-fit  the  base  of  the  crown  to  the  root 
by  the  lieliJ  of  a  narrow  strij)  of  carbon  (articula- 
ting) paper  with  a  hole  punched  for  the  j)assage 
of  the  pin.  Press  the  crown  to  place  on  tlie 
root  with  the  paper  intervening.  Grind  away 
the  points  of  contact  thus  blackened  on  face 
of  root  or  base  of  cro%\n.  If  the  pin  jams, 
reduce  it  by  filing.  The  use  of  a  pamt  of  olive 
oU  and  vermilion  in  the  hole  %\  ill  facilitate  this 
process,  and  wfil  also  facilitate  the  fine-fitting 
of  the  porcelain  base  to  the  root.  \\Tiile  using 
paint  the  parts  must  aU  be  kept  perfectly  dry ; 
and  when  it  is  finished  with,  the  parts  nuist  be 
well  \\ashed  with  soap  and  water  or  a  solution 
of  washing  soda  to  remove  all  traces  of  it. 
Frank  Harrison  recommends  that  the  ^^■edging 
point  of  the  pin  be  indicated  by  previously 
smoking  it  with  a  burning  match  or  taper, 
and  seeing  wliere  it  blackens  the  inside  of  the 
hole. 

To  Fit  a  Logan  Crown  hy  Means  of  a  Model. 
Technique. — Prepare  the  root  exactly  as  before, 
including  the  hole  for  the  pin.  Take  a  detached 
Logan  pin  or  a  counterfeit  one  made  from  a 
piece  of  copper  or  brass,  see  that  it  will  go  to 
the  end  of  the  hole,  and  solder  a  diaphragm  to 
it  shajjed  roughly  to  the  root-face,  but  a  little 
larger  than  the  root-face  and  turned  down 
rather  sharply  at  the  edges  to\\ards  the  gum. 
Oil  or  soap  the  inside  of  the  hole  and  the  root- 
face.  Place  softened  gutta-perclia  (Hill's  will 
do)  on  the  pin  and  root-surface  of  the  dia- 
phragm, and  press  to  place  on  the  root.  When 
cold  remove  it,  and  see  that  a  good  impression 
has  been  obtained  of  the  mside  of  the  hole  and 
the  root-face  ;  if  not,  rejjeat  the  jirocess.  This 
forms  the  core.  Replace  it  on  the  root,  trim 
off  any  excess  of  gutta-percha,  where  it  projects 
beyond  the  diaphragm,  oil  or  soap  it  all  over, 
and  take  an  impression  over  it  and  the  adjacent 
teeth  in  a  tray,  with  composition  or  plaster,  and 
a  bite.  Wlien  set,  remove  it  from  the  mouth  ; 
fit  the  core  in  its  place  in  the  impression  and 
stick  it  there  with  sticky  wax.  Pack  the  im- 
pression of  the  root-face  and  around  the  pin 
with  copper  or  other  amalgam,  and  the  adjacent 
sides  of  the  two  neighbouring  teeth  with  the 
same.  Cast  the  rest  in  plaster.  This  will  give 
an  accurate  and  durable  model,  to  which  the 
mechanic  will  be  able  to  fit  both  tooth  and  post 
as  well  as,  and  perhaps  better  than,  it  could 
be  done  direct  to  the  mouth. 


580 


2.  To  Fit  a  Detachable  Porcelain  Crown. —  Work- 
ing to  the  Mouth  Direct.  Prejjare  root  as  be- 
fore, except  that  the  hole  in  the  root  should 
be  shaped  to  fit  the  particular  post  that  is  to 
be  used.  Insert  the  pm  in  the  root  loosely  and 
fit  the  crowai  to  it,  bending  the  tenon,  if  neces- 
sary, to  make  it  enter  the  mortise  m  the  crown 
when  the  cromi  is  correctly  aligned  m  position. 
The  fitting  can  be  done  if  desired  to  the  mouth, 
as  in  the  case  of  the  Logan  crown,  and  when 
completed  can  he  fixed  wdth  cement  or  gutta- 
percha as  follows  :  Fix  the  post  first,  and  quickly 
try  the  crown  over  it  before  the  cement  sets.  If 
necessary  rotate  the  post  a  little  with  pliers  until 


4  5 

Fig.  725.— (1)  Detached  Post;  (2)  Detached-post 
Crown  (canine)  fitted  to  root;  (3)  Sectional  view 
of  same;  (4)  Detached-post  Crown  (canine) 
mounted  with  gold  cap ;  (5)  Enlarged  sectional 
view  of  (3). 

{S.  S.  White  Dental  Manufacturing  Co.) 

the  crown  will  properly  fit  over  it.  When 
verified  the  crown  can  be  immediately  fixed 
with  cement. 

The  pressure -casting  method  may  be  used  to 
procure  a  gold  cast  diaphragm  to  fit  the  root, 
and  at  the  same  time  a  bed.  for  the  porcelain 
crown  to  rest  on.  Either  the  casting  may  be 
done  direct  on  to  the  porcelain,  or  the  porcelain 
may  be  detached  from  the  casting  wax  before 
casting,  and  afterwards  fixed  with  cement. 

The  preliminary  processes  may  be  done  either 
to  a  model,  or  direct  to  the  mouth. 

Dire,ct   to   the    Mouth. — Take    a   gold   or   an 


iridio-platinum  tapered  dowel  made  to  fit  the 
hole  in  the  root  loosely,  and  also  to  enter  the 
mortise  in  the  crown ;  this  is  to  be  used  as  a 
core  for  gold-casting.  Grind  the  porcelain  to 
produce  a  fit  at  the  labial  edge  of  the  root  only, 
and  be  free  elsewhere.  Lubricate  the  root-hole 
and  face  with  soap.  Melt  casting  wax  on  the 
dowel  and  force  it  into  the  hole.  Have  a 
sufficiency  of  wax  attached  to  the  post.  Lubri- 
cate the  base  mside  of  mortise  of  crown.  While 
the  wax  is  still  soft,  force  the  crown  into  posi- 
tion. Cool  with  ice-water,  or  ethyl-chloride 
spray,  and  carve  away  excess  of  wax.  Remove 
the  crowai,  and  then  remove  the  rest  of  the  work 
from  the  mouth.  To  effect  this  removal  it 
win  probably  be  necessary  to  seize  the  end  of 
the  dowel  through  the  wax  with  cuttmg  forceps, 
and  the  distortion  of  the  wax  must  be  rectified 
in  the  mouth.  Attach  spnie  to  the  Ungual  free 
surface  and  pressure-cast.  In  this  case  attach 
the  porcelam  to  the  gold  with  oxy-phosphate 
cement. 

It  is,  however,  perfectly  possible  to  pressure- 
cast  direct  on  to  the  porcelain  without  crackuig 
it,  so  long  as  no  wax  Ls  left  outside  the  porcelam. 
In  castmg  direct  on  to  the  porcelain  there  is  a 
risk  of  the  gold  not  fUlmg  the  mortise  in  the 
crown,  and  the  writer's  method  of  overcoming 
that  difficulty  is  to  fill  the  mortise  first  with 
gold  in  the  foUowmg  way  :  Pack  the  mortise 
fuU  of  "Alexander  gold",  and  flush  it  with 
solder  in  the  usual  way  of  making  an  "  Alex- 
ander gold  inlay  ".  This  can  then  be  pressure- 
cast  upon  the  cast  gold  and  will  unite  firmly  to 
that  filling  the  mortise. 

Working  to  a  Model. — Prepare  the  root  and 
fit  the  post.  Place  the  post  loose  in  the  root ; 
take  a  correct  impression  of  tenon  and  root-face 
with  composition  in  a  small  conical  support 
made  of  sheet  copper.  Over  this  take  an 
imj)ression  in  composition  or  plaster  m  a  tray 
in  the  usual  way,  and  a  bite.  On  removal  from 
the  mouth,  fit  the  core,  with  pin  attached,  mto 
the  impression  and  pack  with  amalgam,  and 
cast  with  jDlaster.  To  the  resultmg  model  the 
mechanic  wdU  finish  the  fitting  of  the  crown, 
and  he  will  fix  the  crown  to  the  post  with  oxy- 
phosphate  ;  or  he  will  use  the  pressure-casting 
method  both  to  produce  a  metal  diaphragm  and 
tenon  as  above.  The  final  fixing  in  the  root 
will  then  be  effected  in  the  usual  way. 

Other  makes  of  ready-made  porcelain  crowns 
that  contain  a  hole  or  mortise  to  receive  a  post 
are  :  the  Newland-Pedley  crown,  %\hich  has  an 
oval -in-section-shaped  mortise;  the  Ash's  dowel 
crown,  which  has  a  roimd-in-.section  mortise  ;  the 
Davis,  the  S.  S.  White's,  and  the  De  Trey;  and 
the  Ash's  tube-teeth  (with  or  without  platinum 
tubes),  which  have  a  hole  right  through  them. 

Detachable  Porcelain  Croum  ivith  Cap  and  Pin. 
(1)  Make   a   cap   and   pin   to   fit   the   root   as 


581 


described  below,  and  solder  a  tenon  to  fit  the 
mortise  in  the  crown  on  to  the  cap  (as  on 
p.  585) ;  fix  the  crovvai  to  the  cap  and  tenon 
with  oxy-phosphate  cement. 

(2)  Pressure-casting  Method. — Make  a  cap 
and  pin  as  before.  Cover  cap  with  casting  wax, 
and  force  the  crown  (lubricated)  down  upon 
it  into  position.  Remove  from  mouth  and 
cast — either  with  porcelain  detached  or  direct 
on  to  porcelain  filled  as  already  described  with 
an  Alexander  gold  inlay.  If  investment  and 
castmg-rmg  be  sufficiently  heated  before  forcing 
in  the  molten  metal,  the  porcelain  will  not  be 
cracked  though  the  gold  be  cast  direct  upon 
it. 

The  Richmond  Crown 

This  excellent  and  time-honoured  type  of 
crown  consists  of  a  cap  for  the  root-end,  a 
post,   and    a    porcelain   face    backed   up    \\ith 


Fig.   726. — Riclimond  Crown. 

gold,  and  is  suitable  for  any  of  the  six  front 
teeth  and  for  premolars  ;  in  the  case  of  jire- 
molars  the  inner  cusp  is  built  up  with  gold. 
The  only  valid  objection  to  its  use  when 
properly  made  lies  in  the  difficulty  of  refacing 
it  in  the  mouth  in  case  of  fracture  of  the  facing  ; 
but  this  objection  is  now  overcome  by  using, 
when  constructmg  the  cro\ni,  the  J.  D.  Logan 
slide  or  the  Bloom's  or  Steele's  facing;  or  when 
one  of  these  special  devices  has  not  been  incor- 
porated in  the  crown,  by  using  the  Dental 
Manufacturing  Company's  attachable  face  (Leon 
Williams)  or  Ash's  ditto.  (These  devices  will 
all  be  described  later  on,  see  p.  591.) 

Technique  :  Preparation  of  the  Root. — Prepare 
the  root  by  grinding  it  down  to  the  edge  of  the 
gum  in  front,  not  quite  so  far  elsewhere,  convex 
linguo-labially,  and  flat  from  side  to  side  (medio- 
distally).  Prepare  the  canal  or  canals  for  taper 
posts — one  post  for  a  single-rooted  tooth,  two 
for  a  double -rooted  premolar.  Now  slightly 
cone  the  root-end  by  removing  the  remaining 
strip  of  enamel,  and  by  otherwise  reducing 
the  periphery  of  the  root-end  l)y  meaiLS  of  the 
methods  and  the  instruments  described  and 
figured  on  p.  562.  No  suspicion  of  any  under- 
cut edge  is  to  be  allowed  to  remain. 

Making  the  Collar. — Take  a  strip  of  22-carat 
No.  4  gold  long  enough  to  encircle  the  root  and 
deep  enough  to  allow  of  the  amount  of  festooning 


that  the  band  will  require.  Bend  tliis  in  the 
form  of  a  band  to  fit  accurately  and  tightly 
the  root-end,  festoon  it,  and  solder  it  (as  de- 
scribed for  making  the  band  of  an  all -gold 
crowni  on  p.  562).  Now  place  the  band  in 
position  on  the  root-end,  and  with  a  steel  point 
mark  the  {)osition  of  the  root-face  inside  the 
band  all  round.  Remove  from  the  mouth, 
and  with  scissors  cut  away  the  part  that  stood 
clear  of  the  root -end.  The  band  has  now  been 
reduced  to  the  dimensions  of  a  collar.  Rock 
the  collar  into  position  on  the  root.  Now  take 
a  carborundum  wheel  and  grind  down  the  collar 
on  the  labial  aspect  and  also  the  root,  until  the 
wheel  touches  the  gum  in  front ;  and  also  grind 
the  remaining  part  of  the  collar  and  contained 
root  until  both  are  on  an  exact  level.  Now 
prise  the  coUar  off,  and  fit  and  solder  a  dia- 
phragm to  it,  converting  it  into  a  cap.  For  the 
diaphragm  use  the  same  gold  (22-carat,  No.  4), 
and  before  soldering  it,  see  that  it  lies  snugly 
on  the  edge  of  the  collar,  especially  on  its  con- 
cave labial  edge.  Solder  over  a  Bunsen  burner. 
The  cap  is  now  made,  in  the  rough.  Trim  the 
outstanding  edges  of  the  diaphragm.  Punch 
a  central  hole  in  it,  or  two  holes,  according  as  the 
root  has  one  or  two  canals,  aiming  at  getting  these 
holes  to  correspond  with  the  holes  in  the  root. 
Place  the  cap  on  the  root  and  rock  it  with 
considerable  force  into  place.  Now  take  the 
taper  drill  and  run  it  through  the  hole  or  holes 


Fig.   727. — Wliite''^  improved  Plate  Punch. 

(.S.  S.  White  Dental  Mantifaeturhig  Co.) 

in  the  cap  right  to  the  end  of  the  corresponding 
hole  or  holes  in  the  root.  Dry  the  cap  \\itli  hot 
air.  Push  the  post  or  posts  through  the  cap 
into  place  in  the  root,  and  while  all  is  kejit  quite 
dry,  stick  the  posts  to  the  cap  by  melting  sticky 
wax  upon  them  with  a  hot  burnisher.  When 
cold,  carefulh'  prise  off  cap  and  pins  without 
shifting  their  relative  positions,  invest  in  clean 
wet  sand,  and  solder  the  posts  to  the  cap  by 
melting  the  solder  on  the  top,  taking  care  not 
to  run  any  solder  inside  the  cajj.  Now  reduce 
the  outstanding  ends  of  the  pin  or  pins,  in  the 
sense  of  tapering  them  slightly,  to  prevent  their 


58:2 


dragging   tlie   impression  that   is  about  to  be 
taken. 

Tlie  cap  «itli  pins  is  now  complete.  Place 
this  work  on  the  root,  and  take  an  impression 
over  all  with  composition  or  plaster,  and  a  bite, 
usuig,  if  for  a  premolar,  a  Rhodes 's  cro«ai  tray, 
if  for  a  front  tooth,  an  ordinary  crown  tray. 
In  the  absence  of  a  tray,  a  good  impression  can 
be  taken,  either  in  composition  or  plaster,  by 
pressure  of  thumb  and  fingers  of  one  or  both 
liands  through  the  intermediary  of  three  or 
four  layers  of  bibulous  paper.  The  paper  pre- 
vents the  composition  or  plaster  sticking  to 
the  fingers,  and  allows  of  a  continuous  and 
equable  pressure  being  exerted  on  tlie  compo- 
sition or  plaster ;  the  bite  can  often  be  taken  at 
one  and  the  same  time,  provided  that  equable 
pressure  is  kept  up  on  the  outside  of  the  material 
all  the  time.  Cold  water  is  used  to  hasten  the 
setting  if  composition  is  used,  and  is  applied 
to  the  paper  in  situ. 


A  B 

Fig.  728. 

A.  The  correct  way  of  shaping  the  cervical  edge. 

B.  The  incorrect  way. 

Remove  the  impression  from  the  mouth ; 
then  remove  the  cap  and  pins  and  fit  them  into 
the  imjjression,  and  stick  them  there  with 
sticky  wax.  Melt  a  little  pink  wax  over  the 
inside  of  the  cap  and  over  the  pLiis  to  make 
them  easily  removable  from  the  plaster,  which 
is  now  to  be  run  into  the  impression.  The 
Ijite  is  then  cast  and  articulated  to  the  model. 
The  model  will  have  the  n:etal  work  standing 
upon  it  as  in  the  mouth. 

The  base  of  the  model  should  now  have  a 
conical  hole  excavated  in  it  until  the  ends  of 
the  pins  are  exposed  ;  then  by  pressure  on  these 
ends  and  by  slightly  warming  the  cap,  the 
metal  work  will  be  easily  removed  from  the 
model. 

McCuUough,  having  his  root-end  thoroughly 
coned,  makes  the  cap  by  burnishing  inlay- 
platinum  on  an  oxy-phosphate  model  of  the 
root-end.  This  thm  cap  he  strengthens  by 
fitting  a  shallow  vertical-sided  gold  band  round 
it,  and  soldering  the  two  together,  and  floiving 
solder  over  the  top  of  the  platinum  (9). 

Fitting  and  Fixing  the  Porcelain  Facing  by 
Soldering  Process. — The  labial  part  of  the  edge 
of  the  cap,  which  is  formed  by  the  diaphragm, 
is  now  to  be  filed  or  ground  away  a  little  to 
reduce  the  visibility  of  the  cap  and  to  assist  in 
giving  the  porcelain  a  strongly  convex  cervical 
edge  towards  the  gum  (see  Fig.  728). 


Select  a  suitable  plate  tooth  and  back  it  with 
gold.  Now  grind  it  to  a  fine  fit  with  the  cap, 
and  arrange  for  it  to  be  quite  flush  with  the  cap. 
If  necessary  it  can  be  left  projecting,  but  only 
with  a  view  to  grinding  it  away  and  repolishing 
after  the  crown  is  finislied,  so  that  in  the  end  it 
is  left  quite  flush,  with  no  projection. 

If  the  tooth  in  hand  is  an  incisor  or  canine, 
the  facing  is  now  merely  to  be  attached  to  the 
cap  with  wax ;  the  work  is  then  invested  and 
soldered,  and  sufficient  solder  is  flowed  upon 
the  back  and  cap  to  produce  a  good  rounded 
contour. 

If  a  premolar,  in  order  to  build  up  the  inner 
part  of  the  crown  and  the  inner  cusp,  take  a 
small  piece  of  plate  and  bend  it  into  a  half -moon 
shape  and  fit  it  to  the  cap  and  backing,  to 
represent  the  remaining  sides  of  the  crown. 
If  a  pronounced  inner  cusp  is  required,  a  small 
bit  of  plate  should  be  struck  in  a  die-plate  to 
represent  it,  and  after  the  inner  space  between 
the  half -moon  shaped  piece  and  the  backing  has 
been  filled  by  melting  solder  in  it,  the  small 
piece  of  plate  representing  the  cusp  is  to  be 
soldered  on. 

Making  a  Strong  Gold  Tip  for  the  Facing. — In 
case  of  edge-to-edge  bites,  and  in  other  cases 
\\here  the  facing  is  particularly  liable  to  fracture, 
it  can  be  provided  with  a  strong  occlusal  tip  of 
gold  in  the  following  mamier. 

Grind  the  tip  of  the  facing  away  in  an  oblique 
direction  at  the  expense  of  its  irmer  surface  by 
'  holding  it  against  the  flat  side  of  the  grinding 
wheel,  removing  a  sufficient  thickness  to  give 
a  space  between  the  tip  of  the  porcelain  and  the 
bite,  to  allow  a  sufficient  thickness  of  gold  to 
be  added.  Back  the  tooth  with  pure  gold,  Xo.  2, 
or  thin  soft  platinum,  and  burnish  it  to  a  close 
adaptation  to  the  back  and  sectioned  surface, 
allowing  the  thin  metal  to  project  distmctly 
beyond  all  the  edges  of  the  tooth.  The  best  way 
to  make  the  holes  for  the  pins  is  not  to  punch 
them,  but  merely  to  prick  them  with  a  sharp 
steel  point,  making  a  smaller  hole  than  the 
diameter  of  the  jjins.  (Doskow  recommends 
striking  the  thin  soft  backing  into  a  fit  on  the 
back  of  the  facing  by  swagmg  between  this  and 
a  piece  of  moldine,  using  a  light  horn  mallet 
with  a  piece  of  soft  wood  between  the  mallet 
and  the  facing.)  Then,  if  the  pins  have  had 
their  tips  sharpened,  the  thin  pure  gold  backing 
can  be  pressed  down  to  the  back  of  the  porcelain, 
and  the  pins  made  to  force  their  own  way  through 
it.  A  tight  fit  of  the  pins  into  their  holes  is  thus 
secured,  and  borax  and  solder  wUl  be  prevented 
from  flowing  through,  and  thus  a  frequent 
cause  of  cracking  of  the  porcelain  will  be 
avoided.  Then  this  is  reinforced  by  another 
strong  backing  of  No.  7  or  8  plate,  or  crown 
gold,  bent  to  fit,  and  perforated  with  a  punch 
to  allow  the  solder  to  flow  through  it ;    and,  if 


583 


necessary,  a  third  layer  of  plate  parallel  to  the 
sectioned  surface  is  to  be  applied  still  further  to 
add  to  the  thickness  of  the  tip.  This  piece 
must  he  left  long,  beyond  the  tip,  if  the  invest- 
ment is  required  to  hold  it  in  position  during 
soldering,  and  must  be  ground  a«  ay  after  solder- 
ing. None  of  the  metal  must  be  allowed  to  grip 
the  edges  of  the  porcelain ;  otherwise  the  con- 
traction of  the  metal  on  cooling,  after  soldering, 
will  fracture  the  porcelain.  This  is  due  to  the 
fact  that  gold  on  cooling,  shrinks  more  than  does 
porcelain. 

Building  up  the  Lingual  Contour  and  Inner 
Cusp  of  a  Richmond  Crown  by  the  (Jold  Pressure- 
casting  Process. — A  pressure-casting  machine 
is  not  always  avaOable,  but  when  it  is,  the  best 
way  to  proceed  is  not  to  back  the  facing  at  all 
as  previously  described,  but  to  attach  the  facing, 
after  fitting  it  to  the  cap,  with  casting  wax,  and 
to  build  up  the  necessary  contour  and  inner  cusp 
also  with  casting  wax,  and  to  finish  the  wax 
exactly  as  the  finished  crown  is  to  be.  The 
wax  should  be  finished  to  a  jJolish.  Then  a 
sprue  is  to  be  attached  at  a  convenient  spot  and 
the  work  invested  for  pressure-casting.  If  the 
castmg  rmg  and  contents  are  sufficiently  highly 
heated  before  casting,  the  influx  of  gold  upon 
the  jjorcelain  will  not  crack  it,  but  here  again 
the  cast  gold  must  not  be  allowed  to  laf)  over 
the  edges  of  the  porcelam  as  the  contraction 
of  the  gold  would  result  in  fracture. 

A  saddle-back  tooth  can  be  combined  with 
casting,  provided  that  the  tooth  is  first  ground 
so  that  the  cast  metal  will  hold  it  as  in  a  cup. 
The  casting  in  this  case  must  not  be  done  direct 
to  the  tooth  ;  but  the  tooth  must  lie  removed 
from  the  wax,  and  grajihite  rods  inserted  into 
the  holes  in  the  wax  made  by  the  pins.  After 
pressure -casting  the  graphite  is  to  be  with- 
drawii,  and  the  tooth  fixed  to  the  gold  with 
oxy-phosphate. — Weeks. 

Fixing  the  Porcelain  Facing  ivith  Cement. 
Some  operators  prefer  to  fix  all  porcelain  facings 
to  the  metal  ^\ork  with  cement,  so  as  to  avoid 
subjecting  them  to  the  heat  of  soldering,  as  they 
consider  that  soldering  them  reduces  their 
strength  when  it  does  not  visibly  crack  them. 

The  plan  of  S.  H.  McAfee  of  Xew  Orleans  is 
designed  to  this  end. 

Small  tubes  are  used  to  preserve  in  proper 
size  and  alignment  small  holes  through  the 
body  of  the  metal  crown  for  the  pins  of  the 
facing — the  latter  being  cemented  to  place  in 
the  finished  i^iece.  The  tubes,  which  are 
formed  of  about  No.  38  gauge  platinum  on  a 
mandrel  made  of  an  old  instrument,  should 
be  about  J  inch  long  and  of  a  slightly  larger 
calibre  than  the  pins  of  the  facing. 

Solder  the  joint  with  platinum  solder  or  pure 
gold,  cut  off  the  surplus,  file  the  joint  rather 
smooth,  and  flare  one  end  lightly  by  twisting 


agamst  the  taj)ering  base  of  the  mandrel. 
Grind  the  facing  to  the  proper  shaiie,  properly 
incline  the  pins,  adapt  the  backing,  and  punch 
holes  through  it  to  fit  the  tubes  on  the  facing 
side  ;  then  burnish,  and  trim  the  backing.  A 
smooth  tapered  instrument  twisted  in  tlie  facing 
ends  of  the  tubes  will  make  the  backing  go  on 
and  off  the  pins  easily. 

Reinforce  the  backing,  to  ensure  sufficient 
thickness  of  gold  at  the  incisal  edge,  if  desired. 
The  metal  parts  having  been  made  in  any  way 
preferred,  assemble  them  on  the  cast  with 
wax,  taking  care  that  no  wax  flows  mto  the 
tubes,  or  between  backing  and  facing.  Just 
prior  to  the  final  investment,  remove  the  facing, 
and  coat  the  facing  side  of  the  backing  with 
chalk-alcohol  paste,  working  it  into  the  tubes 
to  keep  out  the  solder.  After  the  final  soldering 
is  completed,  cool  off  by  dropping  in  water, 
grind  away  surplus  tube-ends,  roughly  finish, 
and  jjickle.  Roughen  the  inside  of  the  tubes 
(now  simply  holes)  with  a  burr,  cleanse  the 
facing,  etch  its  lingual  side  with  hydrofluoric 
acid,  and  cleanse  again  with  a  brush  to  remove 
the  film  of  dissolved  jjorcelam.  Roughen  the 
pins  or  thread  them  with  a  "  Bryant  repair 
outfit  "  screw'-cutter,  and  cement  the  facing 
carefully  in  place.  If  the  j)ins  do  not  come 
through  to  the  lingual  surface,  close  what  remains 
of  the  holes  with  gold  foil  or  amalgam  after  the 
cement  has  set,  and  finish. 

McAfee  prefers  to  do  the  operating  in  platinum 
for  tubes  and  backing,  and  uses  platiiuun  solder 
to  attach  them,  pure  gold  for  reinforcing  the 
backing,  and  22-carat  solder  for  the  body  of  the 
piece.  It  may,  however,  be  done  in  pure  gold, 
22-carat  solder,  and  18-carat  solder. 

Short  lengths  of  fine  pencil  leads  may  be  used 
in  place  of  platmum  tubes  for  making  the  holes 
into  which  the  tooth-pins  are  to  be  cemented. 
These  points  can  be  placed  in  the  investment 
in  the  same  relation  to  the  pins  as  described 
for  the  platinum  tubes.  After  soldering  is 
complete  the  carbon  points  can  be  removed 
with  a  burr,  thus  providing  holes  for  the  tooth- 
pins.  The  attachment  can  also  be  made  with 
a  small  nut  of  the  "  Bryant  rejiair  outfit "  (see 
p.  592). 

Where  the  backing  must  be  thin  the  Shriver 
method  may  be  used  to  advantage  (see  p.  593), 
but  there  will  be  sufficient  depth  of  holes  in 
most  cases  to  ensure  strong  anchorage  if  the 
pins  are  inclined  so  that  they  will  pass  through 
what  will  be  the  thickest  portion  of  the  metal, 
i.  e.  the  body  of  the  crown. 

The  Tube-tooth  Crown. — This  is  a  modification 
of  the  Richmond  crown  for  premolars  and  is 
a  tube-tooth  mounted  on  cap  and  puis.  It 
forms  one  of  the  most  lifelike  crowns,  and  is 
suitable  when  the  bite  is  not  close. 

Technique. — Make  the  cap  and  pins  exactly 


584 


as  in  the  preceding  case,  and  take  an  impression 
and  bite  in  composition  over  them  m  the 
mouth. 

The  mechanic  will  then  complete  the  crowii 
in  the  workroom.  If  the  cap  has  been  made 
with  a  diaphragm  of  No.  4  gold,  it  will  be  strong 
enough,  but  if  of  thinner  metal,  it  wUl  want 


Fig    729.- 


-Pressure-cast  bases  tor  porcelain  tube-tooth 
crowns. 


reinforcing  by  soldering  down  another  layer  of 
gold  upon  it.  In  the  case  of  single -rooted 
teeth  the  end  of  the  post  projecting  through  the 
cap  may  be  found  to  be  in  the  right  position  for 
the  tube-tooth  to  fit  over  it ;  but  if  not,  and  also 
in  double-rooted  teeth,  the  post  or  pins  must  be 
cut  off  flush  with  the  cap,  a  hole  drilled  in  the 
correct  position,  and  a  new  pin-size  wire  soldered 
into  it  as  follows — 

Select  a  tube-tooth  of  correct  colour  and  size, 
and  large  enough  to  project  a  little  over  all  the 
edges  of  the  cap,  and  roughly  let  it  down  into 
place  on  the  cap.  The  position  for  the  pin-wire 
pin  is  now  to  be  got  by  meltmg  a  little  wax  on 
the  cap  and  pressing  the  base  of  the  tube-tooth 
(wetted)  into  place  on  it.  On  removal  of  the 
tooth  a  little  column  of  wax  will  be  seen  standing 
at  the  spot  where  the  hole  must  be  drilled.  The 
hole  is  then  drUled,  and  the  pin  jammed  mto  it 
and  soldered. 

The  tooth  is  now  tried  on  the  cap,  and  any 
deviation  of  the  pin  from  the  proper  direction 
rectified  by  bending  with  pliers.  The  tooth  is 
let  down  to  a  fine  fit  on  the  cap  bj'  the  use  of 
colour  paint  and  the  wheel  in  the  usual  way,  and 
the  occlusal  surface  ground  to  fit  the  bite.  The 
parts  are  thorouglily  cleaned  by  washing  with 
hot  water  and  soap,  or  soda  solution,  and  then 
with  clean  hot  water.  When  quite  dry  the 
tooth  is  attached  to  the  cap  and  pm  by  sulphur- 
ing or  oxy-phosphate.  When  set,  the  projecting 
edges  of  the  porcelain  next  the  cap  are  to  be 
ground  down  flush  with  the  gold,  and  the  labial 
and  lingual  surfaces  at  and  near  the  occlusal 
edge  will  want  grinding  in  to  make  these  surfaces 
conform  to  the  natural  shape.  Wlien  all  is 
ready  the  ground  surfaces  are  to  be  rubbed  with 
fine  emery  cloth,  and  then  polished  with  a  buff 


wheel  and  pumice  powder  on  the  lathe.  French 
blue-black  emery  paper,  covered  with  emery  as 
fine  as  flour,  is  capable  of  producing  a  good 
polish  without  recourse  to  the  lathe,  and  is  of 
great  service  in  the  surgery  for  this  purpose. 
Any  excrescence  inside  the  cap  formed  by  the 
end  of  the  pin  must  be  removed  with  a  round 
burr  if  it  threatens  to  interfere  with  the  fit  of 
the  cap  on  the  root. 

The  tooth  must  now  be  tried  in  the  mouth  and 
the  bite  adjusted.  Wlien  finished  the  crown  is 
to  be  fixed  with  oxy-phosphate.  The  bite 
should  then  be  again  verified  with  carbon  paper 
and,  if  necessary,  finally  adjusted  by  grinding 
the  porcelain  out  with  small  diamond  points  ; 
or  a  prominent  cusp  of  enamel  on  the  opposing 
tooth,  if  interfering,  may  be  ground  down  to  a 
moderate    extent,    instead    of    weakening    the 


fi9p 


S? 


Fig.   730. — Diamond   Points,   for  fine-fitting  crown  to 
bite,  if  required,  after  fixing. 

[Dental  Manufacturing  Co.,  Ltd.) 

porcelain  by  excessive  grinding.  In  case  of 
fracture  at  any  subsequent  period  the  crowTi 
can  easily  be  provided  with  another  tube-tooth 
without  interfering  with  the  metal  work — a  point 
of  great  importance  in  preserving  the  root 
from  further  interference.  Another  way  of 
fixing  the  crown  is  to  use  gutta-percha ;  m  that 
case,  of  course,  the  whole  piece  can  easUy  be 
removed  at  any  time  by  heating  it. 

The  Richmond  Type  in  Conjunction  with  Ready- 
made   Porcelain   Crowns,  having    in    the   Base   a 


Fig.   731. — Ash's  Dowel  Crowns  (for  lower  teeth). 
{Messrs.  Claiidius  Ash,  Sons  &  Co.,  Ltd.) 

Mortise,  e.  g.  an  Ash's  dowel  crown  (see  Fig.  731), 
a  Newland-Pedley,  a  Davis,  a  Wliite's,  or  a 
De  Trey  crown. 

These  crowns  have  the  advantage  of  presenting 
a  continuous  surface  of  porcelain,  not  being 
perforated  by  tube  and  pin,  and  wlien  the  bite 
is  not  close  will  prove  admhable  for  the  purpose. 
The  mortise  or  cell  is  always  of  larger  calibre 
than  pin-size,  and  a  dowel  pin  or  tenon  must  be 


585 


made  to  fit  it  closely.  The  Xew  land-Pedley 
cro\vn  has  a  plain  hole,  oval  in  section,  and  this 
must  be  met  by  using  oval  wire.  (Unfortunately 
this  crown  is  not  bemg  manufactured  at 
present.) 

Making  the  Dowel  Pin  or  Tenon  to  Hold  the 
Porcelain  Tooth. — After  the  tooth  has  been 
finely  fitted  to  the  cap,  a  tenon  is  made  from 
large  wire  to  fit  the  hole,  but  not  tightly.  It  is 
inserted  loosely  into  the  hole  and  then  cut  and 
ground  down  almost  level  with  the  base  of  the 
tooth.  A  muiute  amount  of  sticky  wax  is  now- 
melted  upon  the  base  end  of  the  tenon,  and  a 
similar  amount  on  the  centre  of  the  cap,  and 
the  two  are  pressed  together,  the  porcelain 
having  been  slightly  \\etted.  On  withdrawal  of 
the  tooth,  the  tenon  will  be  found  adhermg  to 
the  cap,  and  must  be  soldered  in  that  position 
while  held  by  an  investment  of  wet  clean  sand. 
The  coronal  end  of  the  tenon  can  then  be  reduced 
slightly  in  length  if  necessary,  and  the  crown 
fine-fitted  over  it.  After  thoroughlj'  cleaning, 
the  porcelain  can  lie  fixed  to  the  cap  and  tenon 
with  oxy -phosphate. 

Renewing  the  Porcelain  Part  in  the  Motith  in 
Case  of  Fracture. — Take  an  impression  and  bite 
with  composition  in  Rhodes 's  crown  tray.  To 
make  the  model,  jjack  the  impression  of  the  cap 
and  pin  with  amalgam  or  Harvard  cement,  and 
cast  the  rest  with  plaster.  Fit  a  new  tooth  to 
this  model  and  bite,  and  cement  it  in  the  mouth 
with  oxy-phosphate. 

hi  Cases  of  Close  Bite. — Supposing  a  fracture 
occurs  through  closeness  of  bite,  and  it  is  decided 
that  porcelain  alone  is  not  sufficiently  strong, 
then  make  a  metal  tooth  with  a  porcelain  face 
either  direct  to  the  mouth  or  to  a  model,  as 
follows — 

Method  I. — Take  a  tube  of  thin  platinum,  that 
will  fit  nicely  over  the  pin.  Place  it  on  the  pin 
and  close  its  end  over  the  top  of  the  pui  by 
piuchmg  it  with  pliers.  Make  a  diaphragm  of 
thin  platmum  with  a  perforation  in  the  centre. 
Place  the  open  end  of  the  tube  over  the  perfora- 
tion and  solder  the  tube  to  the  diaphragm. 
Enlarge  the  perforation  in  the  diaphragm  to 
the  full  size  of  the  lumen  of  the  tube.  Place 
this  in  position  on  the  cap  and  pin,  and  press  or 
burnish  the  diaphiagm  into  an  accurate  fit  on 
the  cap.  Now  supposing  that  so  far  the  work 
has  been  done  direct  to  the  mouth,  take  an 
impression  over  all  and  a  bite  in  a  Rhodes  tray, 
and  fit  the  new  work  into  its  bed  in  the  impres- 
sion. Li  the  workroom  the  mechanic  will  then 
fit  a  backed  flat  tooth  to  form  the  buccal  aspect 
of  the  crown,  and  will  build  up  the  rest  of  the 
tooth  with  solder  and  a  U  -shaped  strip  of  metal 
to  form  the  rest  of  the  sides.  When  finished, 
this  porcelain-faced  metal  tube-crown  is  to  be 
fixed  in  the  mouth  with  oxy-phosphate. 
19* 


Metlwd  II. — By  pressure-casting  (working 
to  a  model).  Take  an  impression  in  Ash's  crown 
composition,  in  a  crown  tray,  of  the  metal  work 
standing  in  the  mouth  and  surrounding  parts, 
and  also  a  bite. 

Cast  the  impression  in  amalgam  or  Harvard 
cement.  When  set,  build  up  to  the  model  a 
wax  tooth  with  a  flat  canine  as  porcelain  facing. 
Cast  this  by  pressure-casting.  The  resulting 
porcelain-faced  gold  dowel-crown  is  to  be  fixed 
to  the  -nork  in  the  mouth  with  oxy-phosphate 
cement. 


Fig.   732. — "  Signet-ring  "   Crowns,  showing  porcelain 
facings  backed  and  soldered  to  nietal  rings. 

Method  III. — Make  a  signet-ruig  crown  to  fit 
the  cap  and  fix  it  with  amalgam  or  PcA  (see 
Fig.  732). 

The  BUttner  Crown 

The  Biittner  system  of  crowning  requires  a 
special  set  of  mstruments  for  its  performance 
(see  Fig.  733).  Recognizing  the  great  extra 
security  imparted  to  a  crown  by  a  well-fitting 
cap ;  recognizing  also  that  the  making  of  a  well- 
fittmg  cap  by  hand  is  a  process  requuing  skill, 
care,  and  expenditure  of  time,  the  Biittner  system 
aims  at  a  similar  result  by  a  purely  mechanical 
process.  A  strong  ready-made  circular  cap  is 
provided,  in  various  sizes,  and  the  root  is  cut 
down  to  a  drumhead  by  a  special  trephine,  to  fit 
the  cap. 

The  great  objection  to  the  system  is  that  no 
root  is  strictly  circular  in  section,  and  even  in 
roots  be-st  suited  to  it,  viz.  upper  centrals  and 
canines,  either  the  trephine  will  extend  in  places 
beyond  the  edge  of  the  root-face  and  so  injure 
the  soft  tissues,  or  if  small  enough  to  be  contained 
within  the  periphery  of  the  root -face,  the 
trephine  will  leave  upstanding  edges  of  dentine 
outside  it,  which  will  require  to  be  broken  off, 
thus  leaving  projecting  edges  of  dentine  outside 
the  cap  and  so  preventing  a  flush  finish.  By 
such  an  amount  of  cutting,  also,  the  root-end 
is  of  course  reduced  in  value  jiroijortionately. 
Another  objection  is  that  the  dowel  jiins  and 
the  drills  supplied  are  cylindi'ical  and  not 
tapering. 

Notwithstanding  these  defects  the  system 
has,  in  capable  hands,  succeeded  in  produc- 
ing many  very  durable  crowais.  The  process  is 
capable  of  improvement  by  proceeding  as 
follows  :  First,  use  a  taper  post  fitting  a  taper 
hole  ;  second,  use  a  cap  not  previously  soldered 
to  the  post ;  third,  after  cutting  the  drumhead 
on  the  root,  placing  the  cap  upon  it,  and  the 
post  through  it,  take  an  impression  over  them 


58G 


in  a   conical   naetal   support    (as   described  on  I 
p.  558),  and  a  composition  or  plaster  impression  | 


@@®(o)(o)(o)(o) 


Fig.  734. — Diamond 
Reamers,  for  fit- 
ting porcelain  fac- 
ings to  Btittner 
caps. 

(Messrs.  Claudius 
Ash,  Sons  <£■  Co., 
Ltd.) 


'—{ 


■s>- 


l' 

.'  J 


C.ASM  &  SONS.L? 


I'll:.     ,.:;:_;.       I  Hittnn'  (  Mh\  h   m-l  nnii.'iil-. 

(Messrs.  Claudius  Ash,  Sons  da  Co.,  Ltd.) 


over  that.  To  the  model  thus  obtained,  make 
a  restitution  of  the  original  contour  of  the 
root    outside    the    cap    where    necessary    with 


cast  gold,  so  that  the  \\ork  may  be  finished 
flush  with  the  root.  The  lingual  contouring 
with  gold  and  the  attachment  of  the 
porcelain  face  can  all  be  made  by 
one  and  the  same  operation  of 
casting. 

J.  Leon  Williams'  Modification  of 
the  Buttner  System  (see  Fig.  735). 
J.  Leon  Williams  has  desired  to 
retain  the  advantages  of  the  Biittner 
system  of  a  ready 
made  circular  cap 
and  root  cut 
mechanically  to 
fit  it,  and  at  the 
same  time  to  eli- 
minate the  disad- 
vantages of  the 
want  of  circular- 
ity of  the  root- 
face,  by  sinking 
the  cap  well  with- 
in the  edges  of 
the  root,  and 
combining  it  with 
a  thin  diaphragm 
over    the    whole 

root-face.  He  has  also  provided  a 
taper  j)in  and  a  taper  root-hole. 
These  principles  are  all  good,  but 
as  supplied  the  pin  is  too 
thin,  too  abruptly  tapered, 
too  sharply  pointed,  and 
altogether  too  small. 

The  Partial  Cap,  Pin,  and 
Porcelain  Crown. — Wlien  it  is 
desired  to  get  some  of  the 
advantages  of  a  cap  without 
the  disadvantages  of  its 
showing  at  aU  on  the  labial 
aspect,  a  partial  cap  is  used 
by  some  operators,  notably 
William  Hern.  The  proper 
way  to  make  a  partial  cap 
is  first  to  make  a  complete 
cap  and  then  to  cut  away  as 
much  as  is  desired  to  prevent 
sliowing.  Some  operators 
make  a  jJartial  caj3  by  bend- 
ing a  narrow  strip  of  gold 
t(i  a  model  of  the  tooth, 
jilacing  it  in  position  on  the 
lingual  aspect  of  the  edge  of 
the  root,  and  soldering  it  to 
the  diaphragm,  but  this 
method  is  not  so  accurate 
as  the  preceding,  and  there- 
fore not  recommended.  If 
a  partial  cap  is  justified  at  all,  it  must  fit  very 


perfectly  indeed. 
C.  A.'  Baker   (2) 


recommends   a   diaphragm 


587 


with  a  partial  cap,  and  prepares  the  root-face  in 
a  slightly  different  maimer  from  usual,  as 
follows  :  Prej)are  the  root  as  if  for  a  Richmond 
crown.  Notch  (i.  e.  cut  a  step  in)  the  anterior 
part  of  the  root-face  about  half-way  anterior  to 
the  root-canal  opening  with  a  sharp  inverted 
cone  burr.  Solder  a  diaphragm  of  gold,  24-carat 
32  gauge,  to  an  iridio-platinum  post.  Place  on 
the  root  and  burnish  first  to  the  notched  surface. 
Remove  and  stiifen  that  part  with  solder.  Split 
the  surplus  portion  covering  the  posterior  surface 
so  as  to  allow  the  surj)lus  jJortion  to  be  turned 
up  and  burnished  to  the  lingual  wall  of  the  root, 
thus  forming  a  partial  band.  Thoroughly 
burnish  to  root,  remove  and  invest  in  whitening. 
Flow  solder  to  stiffen  it  and  to  reinforce  the 
portion  that  forms  the  partial  band.  If  the 
porcelain  is  to  be  fused  on  it,  use  platinum  for 
the  cap. 


i 

1 

1     ' 

1 

Vl          V 

v) 

Fig.   735. — Leon  Williams'  Porcelain-faced  Crown. 
(Dental  Mmnikiclurihrj  Co.,  Ltd.) 

The  "Pivot"  Tooth,  or  Diaphragm  and  Pin 
Porcelain  Crown. — The  old  method  of  making 
and  hxing  a  "'  jjivot  "  tooth  is  no  longer  prac- 
tised. It  consisted  of  making  a  hole  in  the 
root  with  a  twist-drill  to  fit  pin-size  wire,  and 
fixing  upon  a  piece  of  plam  pin-size  wire  a 
diaphragm  and  a  tooth.  This  "  pivot  "  tooth 
then  had  its  pivot  jagged  with  a  penknife,  and 
had  floss  silk  wrapped  round  the  pivot.  The 
pivot  was  then  dipped  in  copal  or  mastic  varnish, 
and  was  wxiggled  and  jammed  home. 

The  modern  improvements  consist  in  using 
a  taper  pin  of  much  greater  strain-resistmg 
power  than  the  pin-size  wire,  and  m  usmg  oxy- 
phosphate  cement  as  the  medium  of  fixation  in 
the  root. 

A  large  number  of  roots  present  themselves 
for  crowning  that  are  too  much  decayed  below 
the  gum  to  warrant  their  being  fitted  with  a 


cap.  The  diaphragm  and  pin  crown  is  then 
indicated. 

Technique;  Shaping  the  Boot. — Cut  down 
the  root  to  form  a  face  on  which  the  crown  can 
rest  steadily.  Any  great  obliquity  of  the  root-face 
is  objectionable  as  dimmishing  steadiness.  Make 
the  taper  hole  for  the  pin  (described  on  p.  549). 

Method  I.  Making  to  a  Model. — Take  an 
impression  in  t\\o  parts  as  described  on  p.  554. 
Pack  with  amalgam  or  Harvard  cement,  and 


Fig.  736. — "  Pivot  "Crown 
with  pin  secured  in 
po-sition  and  with  the 
wax  back  modelled  to 
shape. 


Fig.  737. — The  same  with 
sprue-wire  inserted  in 
the  wax. 


cast  model  and  bite.  Make  the  post  of  iridio- 
platuium  or  platinized  gold  and  of  as  large  a 
cross-section  as  the  hole  in  the  root  will  allow. 
Fit  a  diaphragm  of  thin  soft  platinum  or  pure 
gold  to  the  root-face  and  solder  it  in  proj)er 
position  to  the  post.  Burnish  the  diapliragm  into 
a  perfect  fit  witli  the  root -face.  Fit  a  backed 
flat  tooth,  and  solder  together,  flushing  up  a 
lingual  contour  with  the  solder. 

An  alternative  to  this  is  to  dispense  with  the 


Fig.  738. — The  same  with 
sprue-wire  inserted  in 
centre  of  cone. 


Fig.  739. — The  same  with 
metal  cylinder  placed 
over  cone. 


backmg,  and  pressure-cast  the  diaphragm  and 
backing  direct  on  to  the  porcelain  tooth  and 
post,  to  form  the  lingual  contour  (see  Figs. 
736,  737,  738,  739). 

Metliod  II.  Making  to  the  Mouth  without  a 
Model. — -Prepare  the  root  as  m  Method  I. 

Make  a  taper  pin  as  above  of  as  large  a 
section  as  possible  to  fit  the  hole  in  the  root. 
Bend  a  thin  piece  of  soft  sheet  platmum  y^^ 
of  an  inch  m  thickness  roughly  to  fit  the 
root-face.  Prick  a  hole  through  it  opposite 
the    hole    in   the  root.     Push    the    taper   pin 


588 


through  it  uj)  to  its  place  in  the  root ;  this  will 
drive  the  diaphragm  close  to  the  root  round  the 
hole,  and  will  attach  the  diaphragm  to  the  post 


Fig.  741. — SpringTweezers 
for  same  purpose. 
Fig.  740.— Tongs  for  hold-  (S.  S.  White  Dental 

mg  pm  while  soldering.  Manufacturing  Co.] 

(S.  S.  White  Dental 
Manufacturing  Co.) 

firmly  enough   to  allow   both   to   be  removed 

together    and    soldered    without    investment. 

Solder  with  a  very  small  bit  of  solder 

in  a  Bunsen  flame.     Place  again  in 

position  on  the  root,  and  j)ress  the 

diaf)hragm  to  a  fine  fit  on  the  root- 

face    by    means    of    serrated    foot- 

plugger   and    serrated   sjionge-gold 

packer    (see    Fig.    742).    Trim    any 

surplus  edges  of  the  diaphragm  with 

scissors. 

Select  a  f)Iate  tooth,  back  it,  and 
grind  it  to  fit  the  root  in  the  mouth. 
Attach  it  with  sticky  wax  to  the 
diaphragm  and  pin.     Por  this  pur- 
pose   it    will    generally    be    found    Fio.  743. — Le 
necessary  to  reduce  the  labial  side 
of  the  projecting  pin  by  filmg,  and 
to   bend  the  remainder  backwards   (Imgually), 
and  to  notch  the  back  of  the  tooth  and   the 
backing  in  order  to  get  the  tooth  sufficiently  1 
far   back.     When    correctly  fitted  and  waxed  ! 


together,  remove  from  the  mouth,  invest  in  the 
usual  way,  and  solder.  By  this  method  a  crown 
can  be  produced  at  one  sitting. 

These  crowns  are  generally  best  fixed  with 
gutta-percha,  as  afi'ording  a  better  protection 
agamst  further  caries  in  the  root. 

William  Hern  recommends  soldering  a  tag  of 
metal  to  the  lingual  edge  of  the  diaphragm, 
and  allowing  it  to  project  over  the  edge  of  the 
root,  representing  what  may  be  called  about  a 


^ 


Fig.   742. — Serrated  Pluggers  for  swaging  diaphragm 
to  root-face. 
(Dental  Mamifacturing  Co.,  Ltd.) 

one-third  cap,  the  object  being  to  resist  the  bite 
that  normally,  in  the  case  of  the  six  upper  front 
teeth,  forces  outwards  as  well  as  upwards.  His 
method  of  fixing  these  crowns  is  :  first  to  place 
a  thin  disc  of  white  base -plate  gutta-percha  on 
the  diaphragm,  and  force  this,  warmed,  into 
place  on  the  root ;  then,  to  remove  the  work 
from  the  mouth  and  cool  the  adherent  gutta- 
percha ;  and  then,  with  the  gutta-percha  still 
adherent  to  the  crown,  fix  with  cement. 

Building-up  the  Lingual  Contour  with  Porcelain 
Body  instead  of  with  Gold. — A  more  translucent 
crown  is  produced  by  fusing  porcelain  between 
the  back  of  the  porcelain  face  and  the  diaphragm, 
using  no  metal  backing  or  only  a  verv  small  one. 


Cron's  Nitrous  Oxide  Blowpipe,  for  use  with  platinum. 
(Denial  Mamifacturing  Co.,  Ltd.) 

but  in  any  case  soldering  the  pins  of  the  facing 
to  the  post  previously  and  using  no  metal  but 
platinum  and  platmum  solder. 

Technique. — Proceed    as    before,    making    a 


589 


diaphragm  and  a  post,  but  taking  care  that  no 
metal  is  used  except  platinum  soldered  with 
platinum  solder  or  pure  gold.  Either  solder 
the  pins  of  the  tooth  firmly  to  the  post,  or  back 
the  tooth  with  the  smallest  possible  backing, 
and  solder  that  to  the  post.  Then  solder  a 
wire  round  the  edge  of  the  diaphragm  on  the 
coronal  side,  and  several  short  lengths  of  wire 
across.  Build  up  the  contour  at  the  back  of 
the  tooth  entirely  with  porcelam  body,  and  fuse 
it  in  the  furnace.  The  porcelain  wiU  attach 
itself,  when  fused,  very  strongly  to  the  pre- 
existing porcelain,  and  the  wires  will  cause  it 
to  be  attached  to  the  diaphragm ;  the  actual 
adhesion  of  porcelain  to  platinum  is  a  negligi- 
ble quantity.  Partly  this  fact,  and  partly  to 
increase  the  translucency  of  the  crown,  are  the 
reasons  why  the  metal  backing  is  either  dispensed 
with  or  reduced  to  the  smallest  dimensions. 

George  Northcroft  recommends  crowns  for 
anterior  teeth  made  by  fusing  up  the  contour 
at  the  back  with  porcelain,  and  says  "  they  are 
so  strong  that  even  an  edge-to-edge  bite  will 
not  smash  them  ". 

The  All-Porcelain  Cast-Gold  Crown,  when  made 
with  detachable  porcelain  crown  to  the  mouth 
without  a  model. 

Technique. — Prepare  the  root  as  before,  aiming 
at  a  domed  root-face.  Then  countersink  the 
orifice  of  the  root-hole,  when  there  is  plenty  of 
root-substance  to  deal  with  ;  also  cut  a  transverse 
groove  in  the  dentine  of  the  root-face,  not  neces- 
sarily extending  to  the  periphery  of  the  root, 
half-way  between  the  root-hole  and  the  lingual 
edge.  Connect  this  groove  with  the  orifice 
of  the  root-hole  by  means  of  another  groove 
at  right  angles  with  it.  Fit  a  taper  post 
(iridio-platinum  or  platinized  gold),  allowing  it 
to  project  about  liy  inch  to  form  the  tenon. 
Fit  the  crown  closely  to  the  root  at  the  labial 
edge,  leaving  a  distinct  space  behind  of,  say, 
Jg  inch.  Soap-solution  the  inside  of  the  canal 
and  root-face.  Place  softened  casting  wax  on 
the  tajjer  post.  Soap-solution  the  ba.se  and 
mortise  of  the  crown.  Use  the  crown  as  a 
pliuiger  and  force  the  post  nearly  home  on 
the  root  with  it.  Remove  all  from  the  mouth 
and  trim  off  the  excess  of  wax.  Replace  in 
the  mouth  and  force  the  crown  quite  into  place. 
Burnish  the  wax  with  a  smooth  burnisher  to 
make  it  accurately  flush  with  the  edges  of 
the  root-face.  Cool ;  remove  the  crown  only 
from  the  mouth.  Clear  away  enough  casting 
wax  from  the  tenon  of  the  post  to  get  a  good 
grip  of  it  with  cutting  pliers.  Force  the  crown 
on  again.  Remove  it.  Seize  the  tenon  with 
pliers,  and  remove  post  and  wax  from  the  root. 
Replace  the  crown  on  the  post  and  wax.  Melt 
the  edge  of  the  wax  to  the  edge  of  the  porcelain 
crown,  takmg  care  not  to  interfere  with  the 
fit  of  the  wax  to  the  root-face.     Remove  the 


porcelam.  Attach  sprue  to  the  lingual  part  of 
the  wax,  invest  the  whole,  and  cast  with  gold. 
Attach  the  porcelam  with  oxy-phosphate. 

The  counter-sinking  of  the  root-face  is  to 
give  a  secure  seating  for  the  crown  ;  the  grooving 
is  to  increase  the  strength  of  the  attachment  of 
the  crown  to  the  root  and  to  prevent  rotation, 
and  bemg  situated  behind  the  line  of  greatest 
weakness  of  the  root,  it  does  not  increase  the 
liability  to  fracture.  ^ 

Another  way  is  to  fill  the  mortise  in  the 
porcelam  crown  with  an  Alexander  gold  inlay, 
and  to  pressure-cast  direct  on  to  tlie  porcelam. 

Porcelain-faced  Cast-Gold  Crown. — This  is  pro- 
duced m  a  manner  similar  to  the  preceding, 
but  usmg  an  ordinary  flat  plate  tooth  instead 
of  a  dowel  crowri.  The  casting  should  be  done 
direct  to  the  porcelain,  and  if  the  wax  is  not 
allowed  to  overlap  the  edges  of  the  porcelain, 
and  the  work  is  sufficiently  heated  up  in  the 
investment  before  forcing  in  the  molten  gold, 
no  harm  will  result. 

F.  E.  Roach  (15)  assumes  that  it  is  necessary 
to  remove  the  porcelain  tooth  from  the  wax 
and  the  rest  of  the  work  before  casting,  pre- 
sumably because  he  fears  fracture,  and  recom- 
mends puUuig  the  porcelain  flat  tooth  away 
from  the  casting-wax  by  means  of  a  piece  of 
sticky  wax  attached  to  the  facing.  Carbon 
points  are  then  inserted  into  the  pin-holes  in 
the  wax  before  investing  and  casting.  He 
secures  the  facing  to  the  backing  by  one  of 
two  means. 

If  the  backing  is  thick  enough  to  cover  the  full 
length  of  pin,  the  facing  can  be  securely  attached 
in  the  following  manner  :  With  a  twist-drill  two 
or  three  sizes  larger  than  pin-holes,  drill  out  the 
carbon  points,  thus  making  the  holes  slightly 
larger  than  the  pins,  to  accommodate  a  sort 
of  head  that  is  made  on  the  ends  of  the  pins  by 
pinching  with  pliers.  Then  carefully  fill  the  holes 
with  cement,  and  with  the  entire  back  of  the 
facing  covered  with  cement  press  it  into  place. 

In  case  of  a  thin  backing,  the  holes,  he  says, 
sliould  extend  through  to  the  lingual  surface 
and  be  slightly  countersunk.  The  puis  are 
cut  off  flush  with  the  surface  of  the  backing, 
and  the  facing  is  secured  to  the  backmg  by 
cementation  and  rivetmg,  which  should  be  done 
before  the  cement  sets,  by  embedding  the  facing 
in  a  softened  mass  of  modelling  composition 
with  the  backing  up\iards,  and  with  a  small 
jeweller's  hammer  riveting  the  ends  of  the  pins 
and  finishing  flush  with  the  lingual  surface  of 
the  backing. 

Making  to  a  Model. — All  these  processes,  when 
no  cap  is  used,  can  be  satisfactorily  performed 
to  a  model  and  a  bite,  made  from  a  good  impres- 
sion of  the  parts,  provided  the  root-face  is  repre- 
sented on  the  model  by  an  amalgam  or  fusible 
metal  surface,  or  by  Harvard  cement. 


CHAPTER   XXXVI 


ARTIFICIAL   CROWNS     {continued) 


REPLACING    PORCELAIN    FACINGS 

When  a  crown  has   been  fixed  with  gutta- 
percha,  it  can   easily  be    removed   by   simply 

{(')  (b) 


tmr 


U)  (fc) 

Fig.    744. — Replacing    a    broken    ordinary    flat    tooth 

with  a  Steele's  facing  in  the  mouth, 
(a)  To  replace  the  broken  tooth;    (6)   Cut  off  pins  and 
stone  the  backing  to  a  flat  surface;    (c)  Grind  a 
Steele  facing  to  fit  the  space  ;    (d)  Flow  a  very  thin 
layer  of  wax  on  the  fiat  svu-face  by  means  of  a  hot 
spatula;     (e)  Moisten   facing   and   press   the   wax 
in   its   correct  relative   position ;     (/)   Slide   facing 
downward  off  the  wax,  disclosing  a  wax  impression 
of  slot  on  the  backing ;  (g)  With  drill  or  handpiece 
mark  location  of  hole  slightly  above  lower  end  of 
the  slot  as  indicated  by  the  wax.     Mark  another 
midway  to  the  gingival  margin ;  {h)  Remove  wax, 
lubricate  with  drop  of  oil,  drill  holes  to  the  depth 
of  the  shank  of  drill.     Hold  drill  straight  and  steady 
to  avoid  enlarging  holes  ;  (/)  Thread  holes  with  tap 
after   oihng;     (j)    Slip    on   facing.     If   screws    are 
correctly  seated,  fill  hole   and  slot  in  facing  and 
cover   the    back   with    cement,   slide    to   position, 
holding  it  until  the  cement  begins  to  set ;  (t)  Where 
a  heavy  tip  has  been  used,  proceed  as  above,  but 
leave  the  tip  untouched.     Grind  a  bevel  on  the 
facing  to  correspond  with  the  bevel  of  the  tip.     Set 
the  screw  nearest   the   incisal  edge    farther   back 
from  the  edge  than  in  ordinary  cases,  and  do  not 
set  deeper  than  required    to   seat  facing   against 
backing. 

lieating,  and  the  necessity  for  retaining  it  in 
the   mouth   during  repairs  will  not  arise  ;   but 


when  fixed  with  cement,  it  is  generally  im- 
possible to  remove  it  without  destroying  it, 
and  much  ingenuity  has  been  expended  on 
the  problem  of  replacmg  the  porcelain  facing 
without  removal  of  the  metal  work  from  the 
root. 

The  problem  has  been  met  on  various  Imes — 
By  originally  constructing  the   crown  with  a 
special  removable  facing:  Steele's,  Bloom's;  or 
on  metal  slides,  J.  D.  Logan's,  Rose's. 

By  applying  fresh  facings  when  ordinary  plate 
teeth  have  been  iised :  ^'arious  methods  and 
devices,  viz.  Ash's  facing,  Leon  Williams'  facing  ; 
soft  soldering  in  the  mouth  (Baldwin) ;  use  of 
part  of  a  J.  D.  Logan  slide  (Baldwin) ;  use  of  a 


590 


Fig.  745. — Bloom's  Interchangeable  Facings. 

(Dental  Maimjacturinij  Co.,  Lid.) 

jacket  crowii  to  enclose  the  old  back ;  Zentner's 
riveting;  Bryant's  nvits  and  screws;  Steele's 
method. 

Devices  Providing  for  Easy  Refacing  Incorporated 
in  the  Original  Construction  of  the  Crown 

Steele's  Facing  (see  Pig.  744). — The  porcelain 
facing  has  a  longitudinal  groove  at  the  back, 
extending  from  the  radical  end  to  near  the  tip; 
this  groove  is  shaped  in  section  like  half  a  dumb- 
bell. A  metal  backing  is  supplied  with  a  ridge 
upon  it,  in  shape  corresponduig  with  the  groove. 
Tlie  porcelain  facing  slides  on  to  the  ridge  and 
when  cemented  is  firmly  held. 

Bloom's  Facing  (see  Fig.  745). — This  is  similar 
in  principle  to  Steele's.  The  difference  is  that 
the  shape  of  the  groove  in  the  porcelain  and 
ridge  on  the  backing  is  simf)ly  wedge-shaped 


591 


in  section,  and  the  groove  in  the  porcelain  is 
lined  with  platinum  foil. 

J.  D.  Logan's  Slide  (see  Fig.  746). — ^\ny 
ordinary  plate-tooth  can  be  made  removable 
by  the  use  of  this  device.  It  consists  of  a  gold 
slide  in  two  pieces,  one  .sliding  within  the  other. 
The  tooth  is  backed  with  the  inner  member ;  and 


Fig.  746. — Logan's  Slide  for  fixing  Removable  Porce- 
lain Facings.     (Dental  Manufacturing  Co.,  Ltd.) 

the  outer  member  is  soldered  to  the  diaphragm 
of  the  crown,  or  whatever  else  it  is  desired  to 
fix  it  to.  The  slide  is  beautifully  made  of  plati- 
nized gold,  and  while  affording  an  absolutely 


Fig.  747. — Rose's  Two-part  Backing.      (F.  Rose.) 

reliable   hold  for  the   tooth,   is   hardly  thicker 
than  an  ordinary  No.  8  backing. 

Rose's  two-part  backing  (.see  Fig.  747)  is  another 
device  that  j)rovides  any  ordinary  plate -tooth 
with  a  sliding  attachment,  and  so  makes  it 
removable.  It  is  not  so  suitable  for  crowns  as 
the  J.  D.  Logan,  as  it  is  irregular  in  surface, 
and  therefore  does  not  lend  itself  to  neat  finish. 
It  is  also  much  thicker  (16). 


Devices  for  Refacing  when  an  Ordinary  Plate-tooth 
has  been  used  in  the  Original  Construction  of 
the  Crown 

Leon  Williams'  Facing  (Dental  Manufactur- 
ing C'omi)any"s,  see  Fig.  748). — This  device  has 
been  made  by  Harry  Rose  for  many  years  for 
his  own  use,  and  also  by  Leon  Williams. 

It  is  a  flat  tooth  in  all  respects  like  an  ordinary 
plate-tooth,  except  that  it  has  no  pins ;  but 
has  instead  of  pins  two  undercut  holes  at  the 


\ 


Fig.  748.- 


^      '  I 

w  '~ ■ 

-Leon  Williams'  Porcelain  Facings. 

(Dental  Manujacturing  Co.,  Ltd.) 


back,  where,  in  a  plate-tooth,  the  pins  would 
be.  These  holes  are  large  enough  for  the 
headed  pins  to  enter. 

Technique. — When  a  facing  is  broken  in  the 
mouth,  remove  all  fragments  of  porcelain, 
but  do  not  remove  the  pins.  Select  a  Leon 
Williams'  facing  that  will  suit  the  case,  and 
that  has  the  holes  in  similar  positions  to  the 
pins  of  the  broken  facing.  Fit  the  new  facing 
into  place  and  cement  it  in. 

The  Dental  Manufacturing  Company  supplies 
pairs  of  facings,  one  with  pins,  and  one  with 


Fig.  749. — Ash's  Repair  Facings. 
(Messrs.  Claudius  Asli,  Sons  &  Co.,  Ltd.) 

holes,  but  otherwise  exactly  alike.  The  idea 
is,  when  making  a  crown,  to  procure  a  pair  of 
facings,  using  at  first  the  one  with  pins  in  the 
ordinary  way,  and  handing  the  one  with  holes 
to  the  patient  to  be  kept  in  case  of  fracture  of 
the  first. 

Ash's  Facing  (see  Fig.  749). — This  is  similar 
to  the  preceding,  except  that  instead  of  having 
two  holes  to  accommodate  the  two  pins,  it  has 
an  undercut  transverse  slot  into  which  the  pins 
are  received.  This  slot  gives  greater  latitude 
in  selection  of  a  facing,  owing  to  its  being  able 
to  accommodate  puis  of  diverse  widths  apart. 


592 


Technique. — Same  as  the  preceding. 
Long-pin  Facings  (S.  S.  White's,  see  Fig.  751) 
(19). — These  can  be  used  for  replacing  a  crowii 


inside  of  the  holes  with  a  cross-cut  fissure-burr. 
Cement  the  facing  into  place. 

Bryant's  Crown  or  Bridge  .Repair  Process  (see 


^;^ 


Fig.  750. — Ash's  Dowel  Crowns,  premolars.      {Messrs.  Claudius  Ash,  Sons  <&  Co.,  Ltd.) 


in  the  mouth  when  there  is  a  sufficient  body 

of  metal  to  enclose  the  whole  length  of  the  pin. 

Technique. — Remove  all  fragments  of  broken 


Fig. 


751. — S.  S.  White's  Long-pin  Facings. 
{S.  S.  White  Dental  Manufacturing  Co. 


Fig.  752). — Bryant's  set  consists  of  two  screw- 
cutting  dies  (Nos.  1  and  2),  a  reamer  (No.  3), 
a  nut-driver  (a  choice  of  two  forms,  Nos.  4  and 
4a),  and  two  gold  nuts  (No.  5) ;  Nos.  1,  2,  and  4 
are  manipulated  bet\\'een  the  tliumb  and  finger ; 
Nos.  3  and  4.\  with  the  right-angle  hand-piece 
on  the  engine. 

The  larger  of  the  two  dies.  No.  1,  is  for  starting 
the  thread  on  the  pin  of  the  repair  tooth,  and 
No.  2,  \^•hicll  is  smaller,  for  completing  it.  The 
reamer.  No.  3,  is  for  shaping  the  lioles  drilled  in 
the  backing  for  tlie  pins  so  that  tliey  will  receive 
the  nuts  (No.  5).  to  the  taper  of  which  it  corre- 
6  5  4 


porcelain,  and  reduce  the 
old  backing  to  a  flat  sur- 
face, removmg  the  jjro- 
jecting  pins.  With  a  fine 
spear-drill  only  slightly 
larger  than  the  pins  of 
the  facing,  drill  two  small 
horizontal  holes  into  the 
old  backing  and  body  of 
the  crown  in  exactly  the 
right  position  to  receive 
the  pins  of  the  long-pin 
facing  .selected.  Letdown 
the  facing  into  position, 
allowing  the  whole  length 

of  the  pins  to  enter  the  holes.  Roughen  the 
pins  thoroughly,  or  cut  a  screw  upon  them 
with    a    Bryant's  screw  cutter.     Roughen   the 


2  «S 

4a    5 
Bryant's  Crown  or  Bridge  Repair  Process. 

{S.  S.  White  Dental  Manufacturing  Co.) 

sponds.  The  nut-driver  (No.  4)  is  for  sending  the 
nuts  (No.  5)  home  upon  the  pins.  A  holder  (No. 
6)  keeps  the  nut  in  line  while  being  started. 


593 


The  process  is  suitable  where  the  metal  work 
at  the  back  of  the  crown  is  thick,  amounting  to 
one  sixteenth  of  an  inch  or  more.  The  old 
backing  is  cleared  of  all  fragments  of  broken 


FiC!.  753. — Shriver's  Bridge-repairing  Drill  and  Pliers. 

(.S.  S.  White  Dental  Manufacturing  Co.) 

porcelain  and  overhanging  edges  and  is  trimmed 
flat.  The  projecting  pins  of  the  old  tooth  are 
cut  away  and  ground  flat.  A  new  ordinary 
flat  tooth  is  selected  to  replace  the  old  one.  Two 
holes  are  drilled  right  through  the  old  backing 
at  the  correct  positions  to  take  the  pins  of  the 


new  tooth.  The  new  tooth  is  fine-fitted  into 
place.  The  holes  are  deeply  countersunk  from 
the  lingual  .side.  The  pins  of  the  new  tooth  are 
threaded  with  small  screw-cutting  dies.  \Vhen 
in  place,  the  tooth  is  secured  by  small  nuts  of 
conical  shape,  which  are  screwed  on  to  the  pins, 
and  sunk  into  the  countersunk  holes  in  the 
backing.  Thin  cement  or  thick  chloro-percha 
can  be  used  as  a  luting  material.  After  the 
cement  has  set,  the  portions  of  the  nuts  pro- 
jecting above  the  level  of  the  backing  can  be 
ground  down  with  small  stones. 

Shriver's  Bridge-repairing  Drill  and  Pliers  (see 
Fig.  753). — This  method  can  be  used  for  refacing 
a  crown  in  the  mouth.  The  old  backing  is 
trimmed,  and  holes  to  take  the  pins  of  the  new 
tooth  are  drilled,  as  in  Bryant's  method,  but  the 
holes  are  only  slightly  countersunk  on  the  lingual 
side.  The  new  facing  is  fitted,  and  its  pins  are 
cut  short  so  that  they  project  only  very  slightly 
beyond  the  back.  The  ends  of  the  pins  are  now 
converted  into  tubes  for  a  short  distance  by 
drilling  along  their  centres  with  a  fine  trochar- 
ended  drill,  which  is  held  in  position  while  doing 
its  work  by  a  small  piece  of  tube  slipped  over 
the  pin.  The  tooth  is  now  smeared  at  the  back 
with  cement,  and  put  in  position  in  the  mouth, 
and  the  tubular  projecthig  ends  of  the  pins  are 
quickly  spread  out  and  riveted  down  by  the 
pressure  of  the  point  of  the  pliers  made  for  the 
purpose. 

The  set  of  tools  consists  of  a  little  drill  to 
countersink  the  ends  of  the  pins,  a  pair  of  pliers 
for  spreading  the  countersunk  pin  to  clinch  it  to 
the  backing  and  for  burnishing  the  A^ork  down 
smooth,  and  a  detached  sleeve,  which  is  set  over 
the  tooth-pin  to  centre  the  drill  in  coiuiter- 
sinking. 

The  pliers  are  much  like  the  old-style  rubber- 
dam  punch  in  appearance.  One  jaw  is  provided 
with  a  pocket  or  bowl  to  receive  a  mass  of 
modelling  composition  to  serve  as  a  cushion  for 
the  lingual  face  of  the  crown  in  fixing  the  new 
facing.  The  other  jaw  has  two  removable 
punches — the  first  \vith  a  cone-shaped  end  to 
spread  the  countersunk  end  of  the  j^in  and  rivet 
it  to  the  backing ;  the  second  with  a  smooth 
rounded  face  to  burnish  the  riveted  end  down. 

Refacing  by  Soldering  in  the  Mouth  (Baldwin). 
This  method  cannot  be  used  in  those  rare  cases 
where  the  pulp  is  still  alive  in  the  root. 

The  old  backing  is  trimmed  down  smooth  and 
flat,  and  the  old  pins  are  cut  off'  and  ground 
smooth.  An  impression  of  the  labial  aspect  only 
of  the  old  backing  and  adjacent  teeth  is  taken  in 
composition,  and  a  plaster  model  cast.  A  new, 
thin,  flat  tooth  is  backed  with  a  thin  backing 
(No.  6  or  7),  which  is  brought  well  to  the  tip  of 
the  tooth ;  the  pins  are  cut  short  and  riveted 
down  into  countersunk  holes  in  the  Ijacking  and 
soldered  with  gold.     The  new   backing  is  now 


594 


filed  smooth  and  flat.  This  tooth  is  fitted 
on  the  model.  The  new  backing  is  then 
'•  tinned  "  by  melting  a  low-fusing  soft  solder, 
called  "  pearl  solder  ",  all  over  it  with  a  copper 
solderuig  bit  (see  Fig.  754  A),  using  hydrochloric 
acid  and  zinc  as  a  flux.  1  he  outer  surface  of  the 
old  back  in  the  mouth  is  similarly  coated  with 
pearl  solder.  The  new  tooth  is  then  placed  in 
position  in  the  mouth,  and  while  it  is  held  by  a 
finger  of  the  left  hand  with  a  small  piece  of 
bibulous  paper  intervening,  the  two  metal  sur- 
faces in  contact  are  made  to  unite  by  melting 
the  intervening  pearl  solder  by  the  application 
of  a  molten  bead  of  pearl  solder  on  the  tip  of 
the  copper  bit ;  this  bead  of  solder  nmst  come 


01.0  e.n<-<^ 


,soi- 


DE.K 


,0,EW  CHCK 


fi!i,L(LHlH     FACE 


iCuPtKiNt 


Fig.     754. — A,   Soldering    Iron ;     B,   Method    of    use.       The 
"  tinned  "  copper  bit  must  toucli  the  solder  on  tlie  tips 
of   the  two   backings,   and  must  not  be  placed  behind. 
{Dental  Mamijacturing  Co.,  Ltd.) 


in  covtact  from  the  first  with  the  pearl  solder 
already  upon  the  two  backings  (see  Fig.  754  B). 
The  moment  of  thorough  melting  can  be  in- 
stantly told  by  feeling  the  tooth  sink  down 
under  the  pressure  of  the  finger.  Directly 
this  is  felt,  the  hot  copper  bit  is  removed 
and  a  swab  of  cold  water  dashed  upon  the 
work.  A  swab  of  cold  water  is  used  in  the 
same  way  immediately  after  each  operation  of 
"  tinning  "  the  old  back  in  the  mouth.  The 
copper  bit  must  be  used  very  hot,  short  of 
redness. 

Precautions  against  heat  being  conducted  to 
serusitive  neighbouring  jiarts  should  be  taken  as 
follows  :  The  rubber-dam  should  be  put  on  the 
crown  and  the  adjacent  teeth.  If  the  adjacent 
teeth  are  live  teeth,  the  old  backing  should  be 
reduced  with  a  dividirg  file  or  diamond  disc  if 


necessary  to  prevent  its  touching  them.  Pieces 
of  thick  l)lotting-paper  can  be  put  between  the 
old  backing  and  the  adjacent  teeth.  All  the 
applications  of  heat  in  the  mouth  must  be  done 
quickly,  and  the  cold  swab  applied  immediately 
afterwards  without  loss  of  time.  No  attempt 
nuist  be  made  to  apply  the  heat  for  the  final 
fusing  through  the  old  backing. 

The  writer  has  performed  this  operation  many 
times  successfully,  and  has  never  had  trouble 
by  causing  pain  to  the  patient.  It  would  be 
possible,  of  course,  to  make  a  preliminary 
injection   of  novocaine. 

Befacing  by  Means  of  Part  of  the  J.  D.  Logan 

Slide  (Baldwin). — This  is  an  excellent  way  of 

refacing  in  the  mouth.     The  old  back  is 

trimmed    flat   in  front  and  the  pins  are 

removed.     The  outer  member  of  a  J.  D. 

Logan  slide  is  then  selected  that  will  go 

in  between  the  adjacent  teeth.     The  old 

backmg  is  ground  clowai  at  each  side  with 

a  diamond  disc  until  it  will  fit  the  slide. 

To  facilitate  this  the  imier  member  of  the 

slide  can  be  used  as  a  pattern ;  laid  upon 

the  old   back,  its  lateral  outlines  can  be 

scratched  with  a  fine  steel  point  on  the  old 

back,  and  the  old  back  can  then  be  ground 

away  up  to  these  lines.     The  ground  edges 

nui.st  be  bevelled  at  the  expense  of  their 

Ungual  surfaces  to  make  them  fit  the  hollow 

dovetail  of  the  outer  member.     The  outer 

member  must  be  pushed  on  as  far  as  it  will 

go.     An  impression  is  then  taken  of  the 

labial  surfaces   of   this   and  the  adjacent 

teeth ;    the    impression    is    removed,   and 

the  outer  member  is  withdrawn  from  the 

mouth  and  fitted  mto  the  impression,  which 

is  then  cast  in  plaster.     A  new  fachig  is 

then    fitted   and    fixed    on   to   the    outer 

member,  the  outer  member  being  used  as  a 

backuig.     The  pins  must  be  cut  short  and 

riv-eted  down  into  countersunk  holes  and 

gold-soldered.      The  outer  member  should 

1  e  kept  full  length,  projectmg  beyond  the  incisal 

edge    of    the    porcelain.     Any    irregularity    of 

surface  inside  the  slide  caused  by  riveting  and 

soldering  must  be  removed  by  filmg  or  grinding. 

The  projecting  part  of  the  slide  can  be  notched 

at  the  sides  to  facilitate  removal  of  the  redundant 

portion  after  fixing.     The  new  tooth  should  tlien 

be  fixed  by  sliding  it  on  m  cement,  and  the 

redundant  portion  of  the  slide  trimmed  away 

with  a  wheel. 

One  of  the  merits  of  the  method  is  that  it 
does  not  thicken  the  metal-\\ork  at  the  back, 
which  is  of  great  importance  in  close  bites. 

Another  Method  of  Befacing  Incisors  and 
Canines  by  making  a  Slide. — In  cases  where 
some  extra  thickness  at  the  back  is  not  contra- 
indicated. 

Instead  of  using  a  ready-made  Logan  slide, 


595 


the  new  tooth  may  be  backed  with  No.  4  soft 
platmum,  the  pins  being  cut  short,  riveted  down 
into  countersunk  holes,  and  soldered,  and  the 
back  left  considerably  wider  than  the  tooth. 
The  old  back  having  been  reduced  laterally, 
the  excess  of  platinum  is  then  bent  round  the 
sides  of  the  old  back,  and  may  either  completely 
cover  the  old  back,  in  which  case  the  edges 
should  be  neatly  fitted  together  and  soldered, 
or  may  be  only  just  large  enough  to  lap  over 
the  edges  of  the  old  back.  In  either  case  the 
platinum  should  be  well  squeezed  by  pliers  on 
the  old  back,  and  well  burnished,  to  ensure  a 
good  fit.     The  new  \\ork  is  finally  cemented  on. 

Some  operators  adopt  the  method  of  com- 
pletely covering  the  old  back  with  the  new 
metal,  but  instead  of  cutting  the  jiins  short, 
they  merely  solder  them  to  the  new  metal, 
allowuig  them  to  project  straight  across  the 
space  between  its  two  layers.  Two  vertical 
slots  are  then  cut  with  a  fissure-burr  in  the 
old  backing  from  the  incisal  edges  sufficiently 
deep  to  allow  the  pins  to  slide  up.  Cement  is 
used  as  the  uniting  medium. 

H.  H.  Bethel  makes  a  new  facing  of  inlay  body, 
fusing  it,  in  cases  «here  the  backing  is  thin  and 
therefore  some  of  the  other  methods  are 
contra-indicated  (8). 

He  proceeds  thus  :  Straighten  the  old  back 
and  bend  it  free  fiom  bite.  File  up  the  heads 
of  the  pins  till  they  are  the  same  diameter  as 
the  rest  of  the  pins.  Burnish  lyVrr  '"•  platinum 
(or  No.  30  gold  for  low-fusing)  to  the  old  back, 
lettmg  the  old  pins  project  through  it.  There 
are  t\\  o  ways  of  getting  the  holes  in  the  facing 
for  the  pins  to  enter.  The  first  is  as  follows  : 
Place  small  platinum  tubes  over  each  pin  and 
a  little  longer  than  the  puis.  Pinch  the  ends 
and  so  close  them.  Remove  the  matrix  and 
tubes  together  by  pressing  beeswax,  slightly 
softened,  on  them  when  in  place  on  the  old 
backing.  Place  a  steel-wire  pin  in  each  tube. 
Coat  with  moistened  whitening  the  end  that 
goes  in  the  tube.  Remove  and  invest  in  pow- 
dered asbestos  two  parts,  plaster  of  Paris  one 
part.  Bake  porcelain  in  such  a  manner  as  to 
avoid  drawing  the  tubes  away. 

The  second  method  is  as  follows  :  Use  no 
tubes,  but  press  hard  wax  on  to  the  matrix 
in  place  of  the  backing.  On  withdrawing  the 
wax,  place  a  pure  gold  pin  in  each  hole,  a 
little  thicker  than  the  tootli-pins  and  long 
enough  to  be  held  by  the  investing  material. 

These  become  embedded  in  the  porcelain,  and 
are  afterwards  cut  off  and  drilled  out.  Roughen 
the  tooth-pins  before  cementing  on  the  facing. 

A   "BRACKET   FIXTURE"    (Baldwin) 

Where  it  is  desired  to  fix  an  artificial  tooth 
without  a  plate  to  a  live  premolar  in  such  a 
way  that  the  metal  will  not  come  to  the  front 


or  show  at  all,  a  fixture  may  be  made  (to  fit 
the  natural  tooth)  to  which  the  artificial  tooth 
is  to  be  soldered. 

The  writer's  plan  is  as  follows  :  For  Pre- 
molars.— Shave  oft  with  a  diamond  disc  enough 
of  the  approximal  surfaces  of  the  premolar 
to  produce  parallelism  of  its  sides,  or  even  to 
produce  surfaces  slightly  approachmg  each  other 
in  the  direction  away  from  the  root.  Then  cut 
out  the  fissure  running  between  the  two  cusps 
with  a  smooth  fissure-burr,  making  a  groove  of 
about  j',;  in.  wide  and  the  same  in  depth. 

Now  construct  a  gold  partial  band  with  a 
cross  piece,  to  fit  the  medial,  lingual  and  distal 
surfaces,  and  the  groove,  as  follows — 

Take  an  impression  of  the  tooth,  soaped, 
oiled  or  vaselmed,  in  a  smaO  copper  cap,  with 
dental  lac  or  crown  comjjosition.  When  chilled 
and  quite  set,  remove  this  and  pack  it  full  of 
amalgam  or  Harvard  cement,  and  set  on  a 
basis  of  plaster. 

Having  obtamed  this  metal  model,  make  the 
partial  band  of  thin  pure  gold  to  it,  and  make  a 
small  tongue  of  pure  gold  to  lie  in  the  groove 
between  the  cusps,  and  lightly  solder  it  to  the 
band  at  each  end.  Fit  this  band  and  tongue 
as  «ell  as  may  be  by  burnishing  it  to  the  model. 
Then  try  in  the  mouth,  bend  a  rather  narrower 
18-carat  plate  band  of  the  same  length  round 
it ;  place  a  bit  of  gold  wire  m  the  groove^  uivest, 
and  solder  all  together.  If  a  castmg  machine 
is  available,  after  thoroughly  fitting  the  inner 
pure  gold  shell,  place  it  on  the  model,  and  on 
the  model  buUd  up  the  outside  of  the  partial 
band,  and  fill  up  the  groove  with  castmg  wax. 
Attach  a  sprue  and  pressure-cast.  Trim  up  the 
resulting  arrangement,  and  try  it  ui  the  mouth. 
Adjust  it  to  the  bite  and  rock  it  completely 
home ;  if  necessary,  fit  it  on  by  means  of 
vermilion  j^aint  as  some  contraction  will  have 
taken  place.  Burnish  the  edges  close  to  the 
tooth  all  round  ;  consisting  as  they  do  of  pure 
gold  of  the  original  band,  this  can  easily  be 
done.  Then  take  a  plaster  impression  over  it 
and  the  adjacent  teeth.  The  mechanic  will 
be  able  to  add  the  porcelam  tooth  to  it  by 
soldering.  Wlien  finished  the  work  is  set 
with  cement ;  but  before  this  is  done,  the  edges, 
filed  thin,  should  again  be  closely  burnished  to 
the  tooth.  This  produces  a  reliable  fixing,  and 
leaves  the  buccal  surface  and  both  the  cusps 
entirely  free  and  unafi'ectcd. 

Another  way  of  producing  this  is  by  making 
the  first  partial  band  of  crown  gold  and  making  it 
quite  a  loose  fit,  and  having  the  casting  wax  in- 
side it  instead  of  outside,  thereby  producing  the 
fitting  portion  and  cross-bar  entu'ely  by  casting. 

THE    CARMICHAEL    CROWN 

For  Premolars. — This  device  is  for  the  same 
purpose   as  the   preceding,   and  like   it   has  a 


596 


Fig.    755.  —  The 
Carmichael  Crown, 


three-quarter  band,  but  it  differs  from  it  by 
requiring  the  inner  cusp  to  be  cut  away  and 
replaced  by  a  gold  cusp,  and  also  by  having  a 
strong  rib  of  gold  running  vertically  on  the 
inside  of  both  medial  and  clistal  portions  of  the 
partial  band.  These  ribs  are  accommodated 
in  the  tooth  by  deep  grooves  cut  by  embedding 
a  fissure-burr  vertically  in  both  medial  and 
distal  surfaces  of  the  natural  crown. 

Technique  for  Premolars  (see  Fig.  755). — Trim 
the  tooth  as  for  the  Bracket  Fixture,  except  that 
the  groove  across  the  occlusal  surface  is  to  be  cut 
a  little  to  the  buccal  side  of  the 
transverse  groove.  Grind  off 
the  inner  cusp  flat,  and  also  the 
inner  jiortion  of  the  base  of 
the  outer  cusp.  Cut  a  groove 
with  a  fissure-burr  in  the  medial 
and  distal  enamel,  continuous 
with  the  transverse  groove,  as 
shown  in  the  diagram,  and 
deep  enough  to  form  a  full  half - 
circle  in  section.  Take  an  im- 
pression and  make  an  amalgam 
or  fusible  metal  model.  On  this  make  the 
three-quarter  band  of  pure  gold  and  burnish  it 
into  a  fit,  and  also  carry  the  gold  over  the  site  of 
the  inner  cusp  and  into  the  grooves.  Lightly 
solder  it  together  and  try  it  in  the  mouth. 
Fine-fit  it  by  burnishing  it  to  the  natural  tooth. 
Then  remove  ;  make  up  the  necessary  thickness 
and  contour,  and  fill  the  grooves  with  casting 
wax  and  cast  it.  In  the  absence  of  a  pressure- 
casting  appliance,  the  added  gold  may  consist 
of  plate  bent  round  to  fit,  and  soldered. 

A  variety  of  the  Carmichael  crown  is  called 
the  "  Staple  "  crown,  because  a  staple-shaped 
piece  of  gold  wire  is  first  made  to  fit  the  tri- 
partite groove,  and  the  rest  of  the  crown 
fixture  is  constructed  over  it  as  before. 

For  Incisors  and  Canines. — These  fixtures  can 
be  constructed  by  making  the  transverse 
groove  across  the  palatal  surface  near  the 
cuttmg  edge,  but  not  near  enough  to  weaken 
the  cutting  edge,  and  the  medial  and  distal 
grooves  in  contiiniation  of  this.  If  the  bite 
is  normal,  accommodation  for  it  must  be  made, 
partly  by  reducing  the  tips  of  the  antagonizing 
teeth  if  necessary,  and  partly  by  removing 
with  a  carborundum  wheel  the  occluding  part 
of  the  tooth  that  is  to  hold  the  fixture,  before 
taking  the  impression. 

For  Molars. — The  transverse  groove  is  made 
antero-posteriorly  right  across  the  masticating 
surface. 

PARTIAL    CROWNS 

Partial  crowns  are  described  in  various  books  ; 
they  consist  of  a  shield  of  metal,  with  a  tag 
soldered  to  the  inside,  for  the  purpose  of  protect- 
ing the  surface  of  large  cement  fillings.    These,  in 


the  opinion  of  the  present  writer,  are  not  of  much 
value,  but  there  is  one  form  of  partial  crown  that 
he  has  found  useful.  It  is  designed  for  those 
cases  where  there  is  a  very  large  open  cavity  in 
a  "  live  "  molar  tooth,  and  it  is  apparent  that 
there  would  be  great  difficulty  in  providmg  for 
the  retention  of  a  filling  without  killing  the 
pulp,  or  further  ^\eakening  the  tooth  by  grooving 
the  edge  of  the  cavity  and  so  providing  it  with 
walls ;  it  may  also  be  desired  to  preserve  the 
whole  of  the  remaining  occlusal  enamel  as  an 
occkiding  surface.  Here  the  object  is  to  band 
the  tooth,  and  by  means  of  the  "  cire  perdu  " 
casting  j)rocess,  to  strengthen  it  inside,  and  fit 
it  more  perfectly,  and  attach  to  it  a  mass  of 
gold,  which  shall  form  a  gold  inlay  for  the 
cavity.  Possibly  there  may  be  two  cavities 
to  be  filled  on  opposite  sides  of  the  same  tooth, 
and  then  both  are  fiUed  with  the  one  fixture. 

Technique.- — Remove  all  caries  and  softened 
tooth  substance,  particularly  all  weak  enamel 
of  the  occlusal  surface.  Then  if  the  rest  of  the 
tooth  presents  any  bulge,  remove  all  the  bulge 
\\itli  carborundum  stones  and  carborundum 
powder,  and  if  necessary  slice  down  the  ap- 
proximal  enamel  both  medially  and  distally, 
so  that  a  band  can  be  fitted  properly  round  the 
tooth.  If  any  enamel  overhangs  the  cavity  or 
cavities,  fill  all  the  undercuts  with  Fletcher's 
artificial  dentine  and  carefully  trim  it  away  from 
all  the  edges.  Make  a  band  of  No.  4  gold, 
22 -carat,  and  fit  it  accurately  and  tightly  at 
the  cervical  edge ;  solder  its  ends ;  contour  it 
neatly  to  the  buccal  and  lingual  surfaces,  and 
give  it  a  jjroper  contact  approximally  with 
the  next  tooth,  but  allow  its  occlusal  edge  to 
stand  free  from  the  tooth.  Adjust  it  to  the 
bite.  Dry  it  and  melt  into  it  casting  wax. 
\Miile  the  tooth  is  wet  press  this  home  upon  it, 
keeping  the  thumb  (wetted)  over  the  occlusal 
end  tightly  to  confine  the  wax ;  then  let  the 
patient  bite  home  and  rub  the  teeth  together. 
Cool  off  with  ice-water  or  ethyl-cliloride  spray, 
and  trim  away  surplus  wax  with  a  warm  scraper. 
Let  the  patient  bite  again  and  grind  the  teeth 
together.  Now  carefully  remove  from  the 
tooth.  If  it  is  desired  to  economize  gold, 
remove  some  of  the  wax  that  entered  into  tlie 
deepest  part  of  the  cavity,  Ijut  take  great  care 
not  to  damage  or  interfere  with  the  wax  at 
the  cervical  and  occlusal  edges.  If  it  is 
necessary  to  add  wax  to  any  part  of  the  outside, 
do  so.  Try  on  the  tooth  again,  if  necessary. 
Attach  a  sprue  or  sprues  to  the  occlusal  part 
of  the  wax  and  pressure -cast  it.  File  up  and 
polish,  and  rock  it  into  place  on  the  tooth  and 
verify  the  bite.  If  properly  done,  the  result 
win  be  a  band  with  gold  inlays  in  the  cavities, 
I  all  fitting  with  great  exactness.  Any  artificial 
dentine  is  to  be  removed  from  the  cavities  in 
the  tooth,  and  the  work  cemented  on  to  the 


597 


tooth  with  oxy-phosphate,  the  band  being 
firmly  rocked  home  under  the  usual  j)i'ecau- 
tion  of  absolute  dryness,  and  tlie  joints,  if  pos- 
sible, varnished  with  chloro-percha  before  being 
allowed  to  get  wet. 

CROWNING    SPLIT   TEETH 

Wien  a  tooth  is  split  vertically  through  the 
natural  crown,  it  will  generally  be  found  that  one 
portion  is  much  looser  than  the  other,  owing  to 
the  fracture  being  quite  oblique  under  the  gum, 
and  in  this  case  the  looser  portion  will  have  but 
a  small  portion  of  root  attached  to  it.  In  such 
a  case  the  looser  portion  should  be  removed 
and  the  remainmg  portion  crowned. 

When,  however,  it  is  manifest  that  the 
fracture  extends  really  between  the  roots  of 
a  multi-rooted  tooth,  and  eacli  portion  of  the 
cro«n  is  attached  to  a  valuable  root,  then  it 
becomes  necessary  to  crown  the  whole  in  order 
to  hold  the  two  parts  tightly  together.  The 
present  wTiter  has  been  successful  in  crowning 
various  cases  of  split  teeth  with  both  shell 
crowns  and  porcelain  crowTis,  some  of  which 
are  doing  perfectly  good  service  after  the  lapse 
of  many  years.  In  such  a  case,  if  some  days 
have  elapsed  since  the  fracture,  it  will  often 
be  found  that  the  two  halves  have  become 
separated  some\\hat  from  each  other ;  this 
means  that  the  roots  also  have  travelled  some- 
what apart.  The  first  thing  then  to  be  done 
is  to  bmd  the  two  portions  tightly  together  with 
silk  or  thread  or  binding  wire,  and  leave  the 
case  for  further  treatment  for  some  days. 
When  the  parts  have  been  thus  brought 
together  absolutely,  the  crownmg  can  be  pro- 
ceeded with.  The  all-gold  (or  platinum)  shell 
crown,  made  in  the  usual  way,  is  the  simplest  and 
best  for  the  purpose.  Part  of  tlie  treatment 
of  the  fractured  halves  should  consist  in  cutting 
a  groove  round  them  parallel  with  tlie  gum, 
fitting  a  soft  platinum  or  Angles  bronze 
regulating  ligature  wire  in  the  groove,  twisting 
the  wire  tight  with  pliers,  and  causing  it  to  lie 
snugly  in  the  groove ;  but  before  fixmg  it,  the 
space  between  the  broken  parts  must  be  very 
thorouglily  cleaned  by  prising  them  apart, 
syringmg,  disinfecting  and  drying,  and  then 
introducing  chloro-percha  containing  chinosol 
or  thymol  between  the  fractured  surfaces,  and 
squeezing  the  parts  tightly  together  with  for- 
ceps. When  there  are  pins  fixed  in  the  roots, 
these  should  be  bound  together  tightly  with 
fine  platinum  or  other  soft  wire  before  super- 
imposing the  crown. 

In  the  case  of  an  upper  first  premolar  fractured 
between  the  roots,  where  it  is  desired  to  crown 
with  a  porcelain  cro\\n,  a  Richmond  cap  crown 
is  indicated,  or  a  porcelain -faced  shell  crown. 
When  possible,  first  bind  the  two  halves  together 
with  a  single  wire  under  the  free  edge  of  the 


gum,  twisting  it  tight  with  fine-nosed  pliers 
on  the  outside.  This  wire  will  greatly  assist 
during  the  trimming  of  the  root  for  the  cap  and 
the  enlarging  of  the  root-canals,  and  during  the 
fixing  of  the  crown  (or  posts),  and  should  be 
removed  after  the  crown  is  finally  fixed. 

FIXING    CROWNS 

Crowns  are  almost  always  fixed  for  a  per- 
manency with  either — 

( 1 )  Oxy-pliosphate  of  zinc  cement ; 

(2)  Oxy-phosi^hate  of  copper  ; 

(3)  Gutta-percha ; 

(4)  A  combination  of  gutta-percha  and  ce- 

ment ;    or — 

(5)  Pc-A.     (For  details  see  p.  .561.) 


Fig.  756. — Rogers's  Wool-roll  Long  Ann  Clamps 

(right  and  left  lower  molar).         ■  rrr,->i 

{Messrs.  Claudius  Ash,  Sons  cfc  Co.,  Ltd.) 


Before  fixmg  any  crown,  the  root  and  the 
crown  must  be  thoroughly  cleaned  and  dried 
with  hot  air,  or  ^^■ith  absolute  alcohol  followed 


Fic.  757. — Gross's  Wool-roll  Clamp. 

(Messrs.  Claudius  Ash,' Sons  tSi  Co.,  Ltd.) 

by  hot  air.  In  some  cases  it  is  possible  to  apply 
the  rubber-dam  to  the  root,  when  the  stump  is 
sufficiently  preserved,  but  not  often. 

To  Achieve  Dryness  of  the  Root. — Have  several 


598 


roughened  Donaldson  liristles  ready  wrapped 
with  absorbent  cotton- wool,  say  three  for  each 
root.  If  an  upjier  tooth,  place  a  roll  of  soft 
bibulous  paper,  or  a  cotton-A^ool  roll,  under  the 
lip  or  cheek,  to  hold  these  jmrts  away  from  the 
site  of  operation.  If  a  lower,  place  a 
roll,  li  ins.  long,  on  each  side  of  the 
root,  to  keep  both  tongue  and  cheek 
or  lip  a\\ay .  Whether  upper  or  lower, 
it  is  advi.sable  to  place  a  pad  be- 
tween the  cheek  and  the  upper  back 
teeth  on  hoth  sides  of  the  mouth  to 
absorb  the  secretion  from  Sten.'^on's 
ducts.  Dry  the  root-face  and  mouths 
with  pellets  of  alisorbent  cottoIl-^\ool  or 


fill  the  cap  or  shell  with  it ;  then  apply  some  of 
the  cement  to  the  mside  of  the  root-canal  or 
canals  with  the  cotton -^^Tapped  wire.  Place 
the  crown  in  position  and  press  home  with  a 
notched  handle  or  a  boxwood  "rocker",  using 


Fig.  758. — Stokes's  Clamp  for  use  with  absorbent  paper. 
{Messrs.  Claudius  Ash,  Sons  tSk  Co.,  Lid.) 

Then  dry  the  canals  with  the  cotton-wrapped 
Donaldsons.  Blow  hot  air  on  the  root-face  and 
into  the  canals  (after  using  absolute  alcohol  if 
desu-ed).  If  any  point  of  gum  threatens  to 
e.xude  moisture,  touch  it  with  Merck's  perli^drol 
(William  Hern)  and  dry  again. 

(1)  To  Fix  with  Cement  {Oxy-jihosphate  of 
Zinc). — Place  everytliing  to  hand  that  v,il\  be 
required.  Have  one  stout  specially  roughened 
Donaldson,  wrapped  with  cotton-wool,  for  the 
sole  purpose  of  aiDplying  cement  to  the  inside 
of  the  canals,  and  a  white  porcelain  slab  within 
easy  reach  of  the  right  hand,  and  fixed  down  to 
the  table  on  which  it  rests.  On  this  place  the 
fluid  and  powdered  portions  of  the  cement  side 
by  side  in  two  patches,  and  a  little  hydro- 
naphthol ;  also  a  notched  handle  for  front  teeth 
or  a  boxwood  "  rocker  "  for  back  teeth.  After 
drying,  rub  the  root-face  and  the  inside  of 
the  canals,  and  also  the  post  of  the  crown 
and  the  inside  of  the  cap  or  base  of  the  crown, 
with  the  fluid  part  of  the  cement  to  be  used ; 
then  remove  any  excess  of  this  fluid  with  dry 
cotton-wool.  The  effect  of  this  is  to  make  the 
cement  attach  itself  much  more  easily  and 
quickly  to  the  surfaces  to  be  cemented. 

Mix  the  cement  by  grinding  the  powder  little 
by  little  with  considerable  pressure  into  the 
fluid,  using  a  large  stiff  steel  spatula  elliptical  in 
section.  When  mixed  first  apply  some  of  the 
cement  to  the  post  and  base  of  the  crown,  and 


Fig.    759. — Goodhugh's  Clamp. 
{Messrs.  Claudius  Ash,  Sons  &  Co.,  Ltd.) 

considerable  force.  A  front  tooth  requires  the 
notched  handle  and  a  slight  rotation  in  each 
direction,  accompanied  by  strong  pressure  in 
the  direction  of  the  length  of  the  root.  A  back 
tooth  requires  the  "rocker"  with  forcible 
pressure  and  a  rocking  motion.     The  surplus 


599 


cement  should  squeeze  out  all  round  and  may 
at  once  be  wiped  away  with  a  pellet  of  cotton- 
wool, whOe  the  pressure  is  maintamed  for  a 
few  minutes.  The  remaining  excess  of  cement 
should  then  be  removed,  and  the  cervical  edge 
of  the  crown  and  the  gum  in  contact  with  it 
flooded  with  chloro-percha,  which  should  be 
evaporated  off  with  hot  air.  The  film  of  gutta- 
percha is  to  jH-otect  the  edge  of  the  cement  from 
saliva  until  thoroughly  set,  and  so  increase  its 
durability. 

(2)  Oxy-phosphate  of  Copper. — This  is  said  to 
be  more  insoluble  in  the  saliva  than  oxy-phos- 
phate of  zinc,  and  also  antiseptic  and  non- 
absorbent.  It  has  the  disadvantage  of  being 
coal-black  in  ccilour  and  showincr  an  ul'Iv  lilack 


Fig 


-Evans's  Gutta-percha  Cement,  and  outfit  for  setting  crowns 
and  bridges.      {Dental  Mariufacturiny  Co.,  Ltd.) 

line.     The  manipulations  are  the  same  as  for 
the  preceding. 

(3)  Gulta- percJia  is  a  very  valuable  medium 
or  fixing  crowns  as — - 
(a)  It  holds  very  securely  in  all  cases,  except 
short   crowns   witli    poor   attachments 
and  subjected  to  great  strains  ; 
(h)  It  protects  the  root  very  reliably  from 
caries ; 

(c)  It  makes  the  crown  easily  removable  at 

the  will  of  the  operator; 

(d)  It  is  quite  insoluble. 
The  disadvantage  is  that  it  is  sometimes  very 

difficult  to  get  tlie  crown  to  go  quite  so  close  to 
tlie  root  as  with  cement. 

The  best  kinds  of  gutta-percha  at  present  are 
base-plate  gutta-percha,  and  Hill's.  Evans's 
gutta-percha  "cement  '  is  an  impure  gutta- 
percha, similar  to  Hill's  (see  Fig.  760). 


Technique. — ilake  dry  and  keep  diy  as  before 
both  the  stump  and  the  crown.  Place  the 
cro^vn  on  a  heater  to  keep  hot  (a  hot  block  of 
steatite  or  hot  copper  slab).  Coat  the  inside 
of  the  root-canal,  and  all  the  parts  to  be  united, 
with  cliloro-percha.  and  put  a  little  column  of 
gutta-percha  into  the  canal  or  canals.  Pack  a 
sufficiency  of  hot  gutta-percha  on  to  the  base 
of  the  crown  and  round  the  pin  or  pins.  Heat 
it  all  finally  and  slowly  press  the  crown  home. 
If  there  is  evidence  of  pain  from  heat,  slightly 
withdraw  the  crown  and  wait  a  little  ;  then  press 
it  home  again.  It  may  go  right  home,  and  give 
evidence  of  there  being  sufficient  gutta-percha 
by  this  squeezing  out  all  round;  but  if  either 
there  is  no  surplus  expressed,  or  the  crown  fails 
to  go  quite  home,  it  must  be  with- 
drawni  from  the  mouth,  and  either 
a  little  more  gutta-jjercha  added, 
or  a  little  taken  away,  as  the  case 
requires.  After  reheating  press  it 
home  again.  It  is  generally  best 
to  remove  it  and  adjust  the  amount 
of  gutta-percha,  and  reheat,  and 
again  press  home,  several  times,  to 
ensure  that  the  crown  shall  get 
quite  into  its  proper  place. 

White  or  red  base-plate  gutta- 
percha is  excellent  where  there  is 
no  cap,  and  no  great  accuracy  of 
fit  (e.  g.  Logan  crown),  but  being 
much  tougher  than  Hill's,  it  will 
not  readily  displace  from  under  a 
cap,  and  in  such  cases  should  not 
be  used.  Where  it  is  desired  to 
increase  the  adhesion  of  gutta- 
percha to  a  tooth  or  crown,  apply 
to  the  surface  a  solution  in  chloro- 
form of  ordinary  resin  (rosin). 

All  impure  gutta-percha,  which 
softens  at  a  low  heat,  for  fixing 
erowiis  and  bridges,  with  instru- 
ments to  work  it,  is  sold;  it  is  called  Evans's 
Gutta-percha  Cement.  The  wTiter  recommends 
a  mixture  of  chloroform  and  eucalyptus  oil  to 
be  placed  on  the  gutta-percha  while'  it  is  being 
heated.  L.  G.  Noel  (13)  recommends  for  setting 
crowns  and  bridges — 


gr.  x\. 


Chloroform 

Eucalyptus  Oil   . 

Aristol 

Gutta-percha      .         .         .      q.s. 

This  takes  a  week  to  dissolve  and  is  used  cold. 

In  using  this  pour  some  of  it  out  on  a  slab 
and  work  into  it  zinc  oxide  till  it  is  of  the  con- 
sistency of  cold  butter. 

(4)  Gombina'ion  of  Gulta-percJia  and  Cement. 
Where  a  crown  fits  loosely,  it  is  recommended 
fii-st  to  coat  the  pin  and  base  with  gutta-percha 
and  force  it  home  completely  on  the  wet  root ; 


600 


then  withdraw  it ;  repeat  this ;  dry  it  and  also 
the  root ;  smear  a  little  thin  oxy-phosphate  over 
the  base  and  pin;  and  quickly  force  it  home. 
A  crown  fixed  in  this  way  is  removable  at  the 
will  of  the  operator  on  reheating. 

WilHam  Hern,  when  fixing  a  diaphragm  and 
pin  crown  (pivot  crown)  or  a  half-collar  crowii, 
always  first  places  a  thin 
washer  of  gutta-percha  over 
the  base  of  the  crown  only  ; 
heats  this,  and  forces  the 
crown  home  ;  then  removes 
it ;  trims  off  the  surplus  at 
the  edges ;  and  then  fixes 
the  crown  in  the  ordinary 
way  with  cement.  This  he 
does  to  give  special  protec- 
tion   to    the    root    against 


REMOVING    CROWNS 

Wlien  a  crowned  tootli 
is  the  cause  of  chronic  ui- 
flammation  or  abscess,  it 
is  necessary  to  remove  the 
crown,  or  di'ill  vertically 
through  it,  in  order  to  open 
out  the  canals  and  rectify 
the  septic  condition  there. 

When  a  crown  has  been 
fixed  with  gutta-percha,  it  is 
only  necessary  to  warm  it 
for'  a  sufficient  time  by 
holding  a  hot  copper  bit 
against  it.  The  metal  will 
gradually  conduct  the  heat 
to  the  remotest  portion  of 
the  crown,  and  then  it  can 
easily  be  pulled  off. 

When  the  crown  has  been 
fixed  with  cement,  and  re- 
c|uires  removing,  it  is  per- 
haps worth  while  trying  a 
preliminary  wriggle  upon  it 
with  a  pair  of  extracting 
forceps,  taking  care  not  to 
use  enough  force  to  cause 
Fig.    7(il.  — Copper-   pai"  or  risk  loosening  the 

ended     instrument    root. 

for  holding  crown  When  it  is  desired  to 
and  maintaining  remove  a  crown,  and  it 
'"'■  cannot  be  done  in  either  of 

the  ways  mentioned,  proceed  as  follows — 

For  Shell  Croivns. — Slit  the  whole  depth  of 
the  crown  at  the  part  most  easily  accessible, 
with  crown-.slitting  forceps  (see  Fig.  762)  (or 
with  a  fine  fissure-burr).  Turn  up  the  cut  edges 
with  a  stiff  sharp  instrument  and  prise  off.  If 
the  crown  still  rcfu.ses,  drill  a  largLsh  hole  hori- 
zontally vvith  a  spear-drill  from  the  slit,  under 


the  occluding  surface,  and  as  close  under  the 
metal  of  the  occluding  surface  as  possible.  Let 
the  hole  go  in  to  a  point  just  short  of  perforating 
the  opposite  side.  Into  this  hole  insert  a  stiff 
strong  instrument,  which  can  be  used  as  a  lever, 
and  tTien  the  crown  can  be  levered  off. 

For  Dowel  Crowns. — A  dowel  crown  remover 
may  first  be  tried,  to  remove  the  whole  crown 
and  pins  together.  If  this  fails,  drill  a  hole 
horizontally  under  the  crown  so  as  to  strike  the 
post,  with  the  object  of  completely  severing  it. 


Fig.      701!.  —  Crown- 

ting  Forceps. 
[Dental        Manujacturinq 
Co.,  Ltd.) 


Fig.  7ti3.  —  Screw-driver 
used  for  levering  off 
crown. 

(S.S.  White  Dental  Manti- 
jacturing  Co.) 


If  the  drill-hole  fails  to  sever  the  post  com- 
pletely, use  a  small  fissure-burr  in  the  hole 
laterally.  Wlien  the  post  has  been  completely 
severed,  the  crown  can  be  easily  pulled  away. 
The  post  left  in  the  root  must  then  be  drilled 
out. 

For  Cap  and  Pin  Crown. — Proceed  as  above, 
and,  if  necessary,  cut  through  the  cap  and  turn 
up  its  edges,  or,  if  necessary,  cut  horizontally 
right  through  root,  pin,  and  cap,  close  to  the 
porcelam,  and  so  completely  amputate  the 
crown  from  the  root.     Then  remove  any  portion 


601 


of  the  collar  still  remaining  and  drill  out  the 
post. 

TREATING    WORN    AND    BROKEN    CROWNS 

Uld  shell  crowns  sometimes  present  them- 
selves with  holes  \\orn  through  the  occlusal 
surface.  Usually  it  is  a  satisfactory  proceeding 
to  burr  out  with  a  round  burr  any  decay  that 
may  have  supervened,  or  to  make  a  satisfactory 
hole  in  the  cement  exposed,  and  then  to  fill  the 
hole  with  amalgam. 

If,  however,  extensive  caries  has  supervened, 
it  is  best  to  remove  the  crown.  The  mechanic 
can  then  mend  up  the  old  crown,  or  a  new  cro\\'n 
can  be  made. 

Where  a  dowel  crown  has  broken,  leaving  the 
dowel  tightly  fixed  in  the  root,  either  the  dowel 


Fig.  7ij4. — Jlosley's  Crown  Remover. 
{Messrs.  Claudius  Ash,  Sons  &  Co.. 


Ltd.) 


may  be  pulled  out,  or,  if  this  is  impossible,  a 
new  crown  can  be  fixed  on  to  the  old  post. 

Types  of  crowns  available  for  fixing  to  an  old 
2)ost  still  in  situ  in  the  root  are — 

The  ordinary  sheU  crown ; 

The  BonwUl  crown,  the  Davis,  Ash's  dowel 
cro\ni,  etc.,  or  a  crown  to  be  specially 
made  for  the  case,  with  tube  or  mortise  to 
receive  the  projectmg  end  of  the  old  post, 
and  if  desh-ed  a  porcelain  face. 


WQien  an  old  "  pivot  "  crown  has  broken  off, 
leaving  the  post  tight  in  the  root,  either  drill 
out  the  old  post  with  a  sharp  stiff  spear-drill 
after  grinding  it  down  flush ;  or  proceed  as 
follows — 

Take  a  small  trephine  and  trephine  round  the 
post  to  a  distance  of  |  or  \  inch.  Fit  an  iridio- 
platinum  tube  in  the  space  thus  made,  and 
construct  a  crown  upon  this  with  a  diaphragm, 
in  the  same  way  as  descriljed  in  making  a 
diaphragm  and  pin  crown,  except  that  the  tube 
takes  the  place  of  the  pin.  Fix  the  new  crown 
with  cement. 

H.  B. 


BIBLIOGRAPHY 


Dent. 


(1)  Badcock,    J.    H.     Molar    Crowns.     Brit. 

Jour.,  1900,  Vol.  XXI,  pp.  429-34. 

(2)  Baker,  C.  A.     Dental  Cosmos,  1907,  Vol.  XLIX, 

p.  578. 

(3)  Baldwin,  H.      On  Cement  and  Amalgam  Filling. 

Trans.  Odont.  Soc,  1896-7,  Vol.  XXIX,  p.  93. 

(4)  Baldwin,     H.      Bicuspid     Crowns.     Brit.     Dent. 

Jour.,  1900,  Vol.  XXI,  p.  429. 

(5)  Baldwin,  H.      Further  Experience  of  Cement  and 

Amalgam     Filling.     Brit.     Dent.     Jour.,     1904, 
Vol.  XXV,  p.  781. 

(6)  Baldwin,     H.     A     New     Method     of     Refacing 

Porcelain-faced    Crowns    in    the    Mouth.     Brit. 
Dent.  Jour.,  1910,  Vol.  XXXI,  p.  G73. 

(7)  Bennett,    Norman   G.     Difficult   Crowns.     Brit. 

Dent.  Jour.,  1908,  Vol.  XXIX,  p.  49. 

(8)  Bethel,  H.  H.     Dental  Cosmos,  1907,  Vol.  XLIX, 

p.  280. 

(9)  DosKow,  Samuel.     The  Banded  versus  the  Band- 

less     Crown.       McCullough's     Crown.       Dental 
Cosmos,  1907,  Vol.  XLIX,  pp.  270  et  seq. 

(10)  Dttnwoodv.    J.    E.     Dental    Cosmos,    1907,    Vol. 

XLIX,  p.  197. 

(11)  Hern,    William.     Incisor   Crowns.     Brit.    Dent. 

Jour.,  1900,  Vol.  XXI,  p.  417. 

(12)  McAfee,    S.    H.     Dental    Cosmos,    June,     1906, 

Vol.  XLVIII,  p.  656. 

(13)  Noel,   L.   G.     Dental  Cosmos,   1907,  Vol.  XLIX, 

p.  453. 

(14)  RiETHMULLER,  R.  H.  and  Hough,  H.     The  All- 

Porcelain  Jacket  Crown.     Dental  Casinos,  1909, 
Vol.  LI,  p.  1258. 

(15)  Roach,  F.  E.     Elliott's  Quarterli/,  October,  1910. 

(16)  Rose,    Frede.     Brit.    Dent.    Jour.,     1906,    Vol. 

XXVII,  p.  865. 

(17)  TuLLER,     R.     B.     Ainer.     Dent.     Jour.  ;      Dental 

Cosmos,  1909,  Vol.  LI,  p.  1016. 

(18)  Weekes,  T.  E.     Dental  Siimmari/.  1910,  j).  105. 

(19)  White,   S.   S.     Catalogue  of  Instruments   used  iti 

Crowning. 


CHAPTER  XXXYII 

BRIDGE-WORK 


GENERAL    BRIDGE-WORK 

Selection  of  Cases. — Tlie  most  important  part 
of  the  work  in  the  construction  of  a  bridge  is 
undoubtedly  the  proper  preparation  of  the 
roots  on  Avhich  it  is  to  be  buUt  up ;  unless  the 
abutments  are  in  a  sound  condition  and  properly 
"  coned  up  ",  the  work  cannot  have  any  lasting 
quality ;  for  no  matter  how  good  the  actual 
mechanical  construction  may  be,  sooner  or 
later  the  bridge  will  fail  if  the  root-treatment 
and  prefiaration  have  been  faulty.  Xow  in 
coming  to  a  decision  whether  a  case  is  a  suitable 
one  for  bridge-work,  the  type  of  patient  must 
be  considered ;  a  neurotic  person  or  anyone 
in  bad  general  liealth  would  hardly  put  up 
with  tedious  and  tiring,  if  not  actually  painful, 
work  incident  to  careful  root-f)reparation. 

Then  it  must  be  considered  whether,  by  put- 
ting a  bridge  in  a  certain  position,  the  whole 
denture  is  thereby  made  good ;  in  a  j)atient 
badly  in  want  of  a  masticatory  apparatus,  to 
put  a  liridge  on  one  side  of  the  mouth  leaving 
the  other  side  with  a  considerable  space  would 
be  bad  treatment ;  yet  one  often  sees  it  done. 
It  must  be  remembered  that  the  chief  use  of 
the  teeth  is  for  masticating  purposes,  and 
bridges  should  be  made  to  that  end;  to  put 
practically  only  facings  in  the  molar  region 
for  show,  is  extremely  wrong,  as  very  often 
some  form  of  plate  would  give  both  use  and 
appearance. 

The  articulation  must  be  taken  very  care- 
fully into  account — i.e.  whether  it  is  normal 
or  nearly  so.  In  so  many  otherwise  suitable 
cases  the  teeth  opposite  the  space  to  be  bridged 
have  elongated  considerably,  making  the  attain- 
ment of  proper  occlusion  almost  impossible 
without  too  much  mutilation  of  the  lengthened 
teeth  ;  a  little  grinding  of  the  prominent  cusps, 
however,  is  quite  allowable,  but  good  occlusion 
must  be  got,  and  in  extreme  cases  it  might  be 
necessary  to  devitalize  and  "crown  "  or  other- 
wise properly  prepare  the  opposing  teeth, 
rather  than  liave  the  occlusion  faulty. 

The  front  upper  teeth  should  not  be  bridged 
if  the  lower  l^ack  teeth  are  missing,  and  are  not 
going  to  be  replaced  with  a  denture  or  saddle 
bridge,  as  in  this  case  a  greater  strain  is  brought 
to  bear  on  the  front  of  the  mouth,  and  the  life 
of  the  bridge  very  much  shortened. 

The  probable  length  of  life  of  a  bridge  in  a 


given  case  must  be  considered,  and  the  patient 
made  to  understand  thoroughly  the  condition ; 
bridges  may  be  made  with  only  a  comparatively 
short  life  in  view,  provided  that  this  is  explained, 
and  that  the  case  does  not  admit  of  more  per- 
manent treatment. 

All  roots  not  to  be  used  as  abutments  must 
of  course  be  removed,  and  never  must  a  bridge 
span  a  root  buried  in  the  alveolus. 

The  question  of  employing  unblemished  teeth 
as  abutments  is  a  difficult  one,  and  as  a  general 
rule,  v,\\en  two  sound  teeth  «ould  have  to  be 
employed  as  abutments,  a  bridge  is  contra- 
indicated  ;  an  exception  would  be  a  case  where 
for  some  reason  it  would  be  difficult  to  make  a 
satisfactory  plate,  and  where  the  space  is  only 
on  one  side.  There  is  no  doubt  that  far  too 
many  sound  teeth  are  sacrificed  to  serve  as 
abutments,  and  very  often  a  plate  is  indicated 
when  the  patient  would  perhaps  prefer  a  bridge. 
Then  again  it  nmst  be  remembered  and  taken 
into  account  that  the  value  of  a  well -constructed 
bridge  as  a  masticatory  apparatus  is  about 
four  times  greater  tlian  that  of  a  plate,  by 
reason  of  resistance  to  pressure  of  occlusion. 

The  use  of  the  cantilever  prmciple  in  bridge- 
work  is  not  to  be  recommended  as  a  general 
rule  ;  that  is  to  say,  when  it  is  possible  to  anchor 
the  bridge  at  both  ends  by  means  of  abutment 
pieces,  or  by  one  abutment  piece  at  one  end 
and  some  variety  of  "  spur  "  at  the  other  end, 
it  is  desirable  to  do  so.  At  the  same  time  the 
cantilever  principle  has  its  use  in  bridges ;  for 
example,  in  a  bridge  from  canine  to  first  molar, 
where  the  remaining  molars  on  the  same  side 
are  absent,  an  extension  of  the  biting  surface 
of  the  molar  may  be  made  backwards  to  the 
extent  of  the  breadth  of  the  second  molar, 
sufficient  strength  being  obtamed  from  the  two 
abutments  to  take  the  additional  strain,  and 
especially  so  if  there  is  an  opposing  artificial 
denture. 

Were  the  force  opposing  a  cantilever  bridge 
applied  only  in  one  direction,  viz.  in  a  direction 
parallel  with  the  axes  of  the  teeth,  the  principle 
could  be  employed  to  a  much  greater  degree  ; 
but  in  the  moutli  there  is  a  side-to-side  move- 
ment during  mastication  and  a  pressure  sideways 
from  the  tongue,  which  must  certainly  preclude 
their  employment  to  any  great  degree,  although 
some  wTiters  contend  that  they  are  perfectly 
satisfactory  even  under  these  conditions. 


002 


603 


General  Condition  of  Mouth  and  Teeth. — The 
more  healthy  and  clean  the  mouth,  the  better 
will  a  bridge  last.  In  case.s  where  there  is 
distmct  recession  of  the  gums  going  on,  bridge- 
work  cannot  be  made  very  lasting ;  the  re- 
cession will  continue  around  the  abutments 
at  the  same  rate  as  before,  if  not  faster,  leaving 
undesirable  pockets  for  food  to  collect  in,  and 
very  great  care  will  have  to  be  taken  to  keep 
the  parts  clean ;  but  still,  as  a  means  of  deferring 
the  wearing  of  a  plate,  it  is  sometimes  desirable. 
A  bridge  acting  as  a  splint  maj^  in  some  cases  of 
pyorrhoea,  considerably  improve  the  condition 
when  in  conjunction  \\ith  other  treatment. 

The  mouth  nuist  lie  put  in  as  healthy  a  con- 
dition as  possible,  and  in  cases  of  gingivitis  or 
pyorrhoea,  removable  ^^•ork  should  be  inserted 
where  possible.  A  bridge  should  not  be  put  in 
the  mouth  of  a  patient  who  does  not  keep  the 
teeth  absolutely  clean,  for  it  is  certain  that 
care  will  not  be  taken  to  keep  the  bridge  so. 

Strain  or  Stress. — Teeth  are  designed  by 
Nature  to  support  each  a  certain  amount 
of  strain  or  stress — the  incisors  an  outward 
and  inward  stress,  the  jiremolars  a  lateral  and 
vertical,  and  the  molars  chiefly  vertical,  ^yith 
a  certain  amount  from  all  sides  according  to  tlie 
position  and  length  of  their  cusps.  When  the 
articulation  is  interfered  \\ith  by  loss  of  teeth 
or  by  irregularity,  the  stress  upon  individual 
teeth,  more  or  less  unsupported  by  neighbours, 
is  increased.  This  is  important  when  considering 
the  advisability  of  bridge-work  in  any  given  case 
— for  instance,  a  first  premolar  as  the  anterior 
abutment  of  a  bridge,  and  having  a  space  betw-een 
it  and  the  canine,  would  make  the  bridge  as  a 
whole  not  so  strong  as  when  the  premolar 
abutment  knuckles  firmly  with  its  neighbour. 

The  greater  the  length  of  overbite,  the  greater 
the  stram  on  the  bridge,  and  if  the  cusjjs  of  the 
bridge  and  those  of  the  opposing  teeth  inter- 
digitate  too  pronouncedly,  the  strain  is  again 
increased ;  of  course  if  all  the  remaining  teeth 
in  the  mouth  articulated  perfectly,  one  could 
articulate  the  bridge  anatomically,  but  it  is 
rare  to  find  the  remaining  teeth  so,  and  therefore 
it  is  better  not  to  have  the  artificial  cusps  too 
pronounced. 

Two  centrals  can  .support  two  laterals. 

Two  laterals  can  support  two  centrals. 

A  central  will  support  a  lateral  with  a  spur 
in  the  canine. 

A  lateral  will  support  a  central  with  a  spur 
in  the  other  central. 

Two  canines  will  support  centrals  and  laterals 
if  the  arch  is  not  V-shaped  and  if  the  overbite 
is  only  very  slight,  and  presuming  there  is  the 
normal  amount  of  posterior  occlusion.  If  the 
arch  is  V-shaped  a  removable  saddle-piece  only 
can  be  used. 


A  central  and  fiist  premolar  may  support 
the  lateral  and  canine,  but  a  removable  piece 
made  with  a  saddle  is  better  than  a  fixed  piece. 

A  canine  and  first  molar  can  support  the  two 
premolars,  and  also  the  lateral,  without  (but 
better  with)  a  spur  in  the  central. 

A  canme  and  second  molar  can  supj)ort  the 
intervening  teeth  if  the  bite  is  not  too  strong. 

The  canuie  to  the  third  molar  should  only  be 
employed  in  a  removable  piece  with  a  saddle, 
and  if  the  third  molar  has  come  forward 
somewhat. 

The  two  canines  and  two  second  molars  can 
supi^ort  a  full  removable  piece  with  saddle. 

The  two  lower  premolars  can  supf)ort  the  two 
molars  in  a  removable  piece  with  saddle. 

The  second  premolar  and  second  molar  can 
supj)ort  the  first  premolar  (without  spur)  and 
first   molar. 

Any  one  tooth  can  sujDport  another  tooth 
with  a  spur  in  adjacent  tooth. 

It  is  always  advisable  in  a  doubtful  case  to 
have  an  extra  abutment  piece  when  possible. 

Devitalization.  —  Teeth  should  practically 
always  ))e  devitalized  before  being  used  as 
abutments  for  bridges.  In  the  earlier  methods 
of  bridge- work  this  was  not  considered  essential, 
but  it  is  impo.ssil)le  to  "  cone  up  "  a  live  tooth 
properly  without  causing  a  great  deal  of  pain, 
and  even  if  the  patient  will  stand  it  there  is 
great  risk,  almost  a  certainty,  of  the  pulj)  dying 
from  chronic  irritation  after  a  varying  period 
of  time.  Open-faced  abutment  pieces  were 
formerly  used,  and  it  was  not  considered  neces- 
sary to  kill  the  jiulp,  as  they  were  put  on  with 
very  little  grinding ;  but  even  if  this  form  of 
abutment  piece  were  sound  (and,  as  will  be 
seen  later,  it  is  not),  more  grinding  away  of  the 
tooth  must  be  done  for  proper  fitting  of  the 
gold  than  can  be  accomplished  without  endan- 
gering tlie  pulp  from  constant  slight  irritation 
of  possible  thermal  changes. 

In  the  rare  cases  in  which  a  patient  would 
stand  the  proper  preparation  of  the  roots,  a 
fixed  bridge  put  on  with  gutta-percha  cement 
would  be  mdicated. 

Those  forms  of  bridges  that  do  not  necessitate 
the  mutilation  of  the  abutment  teeth  can  be 
used  without,  of  course,  interfering  with  the 
pulps  ;  they  will  be  described  later. 

Bridge-work  in  suitable  cases  has  distinct 
advantages  over  "  plate- work  ".  It  admits  of 
greater  masticatory  power  and  it  does  away 
with  the  difficulty  in  some  cases  of  becoming 
accustomed  to  the  "  management  "  of  a  plate; 
also  it  is  occasionally  (but  only  rarely)  found  that 
a  plate  apparently  alters,  or  the  patient  thinks 
it  alters,  the  power  of  speech  and  of  taste.  Then, 
again,  a  plate  in  some  mouths  will  cause  a  con- 
siderable amount  of  abrasion  of  the  remaining 


604 


natural  teeth,  although  theoretically  this  should 
not  hapjjen  in  a  well -adapted  piece. 

The  main  disadvantages  are  devitalization 
of  teeth  that  would  otherwise  be  kept  alive ; 
the  extra  strain  that  is  brought  to  bear  on 
the  abutments ;  unhygienic  conditions  that 
may  supervene  in  mouths  that  are  not  kept 
scrupulously  clean;  and  the  difficulty  and 
tediousness  of  the  work  necessary  to  proper 
adaptation. 

Varieties  of  Bridges. — A  dental  bridge  is  a  masti- 
cating or  incisive  surface  of  gold  or  other  material, 
bridgmg  (or  spaiming)  a  space  in  the  alveolo- 
dental  arch  caused  by  loss  of  one  or  more  teeth, 
and  firmly  anchored  at  either  end  to  one  or 
more  teeth;  if  "removable",  it  may  receive 
additional  support  from  an  alveolar  "  saddle 
plate  ",  and  in  the  case  of  a  removable  "  ex- 
tension "  bridge  it  may  be  anchored  to  teeth 
only  at  one  end,  receiving  its  chief  support 
from  an  alveolar  saddle. 

The  natural  teeth  or  roots  supporting  the 
bridge  are  called  the  "abutments",  and  the 
anchorage  to  them  the  "  abutment  pieces ", 
the  intervening  portion  being  called  the  "  body  ", 
and  the  several  pieces  composing  the  body  the 
"  dummies  ". 

A  fixed  bridge  is  one  in  which  the  body  and 
abutment  pieces  are  one,  and  that  is  fixed 
to  the  abutment  teeth  by  some  form  of  cement, 
and  is  not  removable  by  the  patient. 

A  removable  bridge  is  one  in  which  the  iiuier 
abutment  pieces  only  are  permanently  fixed 
to  the  roots,  the  body  and  outer  abutment 
pieces  being  removable  at  will  by  the  patient 
for  cleansing  purposes.  The  complicated  struc- 
tures sometimes  seen,  which  are  only  removable 
by  the  dentist,  are  not  included  in  the  term 
"  removable  "  in  this  article. 

Fixed  and  removable  bridges  may  be  sub- 
divided into — 

(a)  All  metal — gold,  or  gold  and  platinum. 

(b)  Gold,  or  gold  and  platinum,  with  porcelain 

faces . 

(c)  Fused  porcelain  on  platinum  base. 

General  Shapes  of  Bridges. — In  all  bridges 
as  many  so-called  "self-cleansing"  spaces 
should  be  allowed  as  possible ;  contours  of 
abutment  pieces  should  Ije  arranged  so  that 
the  inter-dental  spaces  between  them  and  the 
adjoining  natural  teeth  are  preserved.  This 
is  of  very  great  importance,  and  just  as  much 
care  must  be  exercised  to  obtain  a  proper 
contact  with  the  natural  teeth  as  would  be 
done  in  the  case  of  a  "  crown  ". 
^^  When  possible  in  posterior  fixed  bridges,  a 
"  bar  "  bridge,  i.  e.  a  biting  surface  without 
dummy  facings,  should  be  used ;  it  is  more 
comfortable  and  allocs  the  food  to  be  managed 


more  easily,  and  is  certainly  far  more  cleanly ; 
the  thickness  of  this  bar  should  be  only  sufficient 
for  requisite  strength,  thereby  leaving  as  much 
space  between  the  "  bar  "  and  the  gum  surface 
as  possible,  and  the  under-surface  should  be 
made  slightly  convex.  By  this  means  the  under- 
surface  is  kept  clean  more  easily ;  the  patient 
can  get  the  tooth-biiish  around  the  abutments 
and  also  pass  the  floss  silk  everywhere.  It  is 
not  so  artistic,  but  one  of  the  main  points  to 
observe  in  all  bridge-work  is  tlie  question  of 
cleanliness.  A  piece  of  linen  can  be  passed 
underneath  a  "  bar,"  and  the  abutment  pieces 
and  under-surface  can  be  kept  comparatively 
clean  on  a  fixed  bridge,  whereas  if  there  are 
facings  the  under-surface  is  extremely  difficult 
to  keep  clean — indeed,  in  many  cases  it  is  im- 
possible— with  the  usual  results  of  gum  surface 
irritation  and  consequent  recession  around  the 
abutments.  However,  in  so  many  cases  the 
teeth  show,  and  there  is  then  no  alternative 
but  to  put  facings. 

In  removable  work  this  does  not  apply,  as 
the  bridge  can  be  removed  at  will  and  kept 
clean.  Facings  on  bridge  abutments  should 
be  kept  absolutely  flush  with  the  band  en- 
circling the  root,  and  never  allowed  to  stand  out 
over  the  gum  as  is  so  often  seen ;  the  gum 
becomes  unhealthy  and  food  collects,  and  the 
piece  never  looks  well  after  a  short  time  in 
the  mouth  ;  even  at  the  expense  of  showing 
a  little  gold,  this  metliod  should  be  adhered 
to.  As  mentioned  elsewhere,  the  overlapping 
facing  may  be  allowed  in  removable  work 
when  necessary,  and  an  improved  appearance 
can  sometimes  be  obtained  by  it. 

Broad  surfaces  of  metal  should  never,  in 
fixed  bridges,  be  allowed  to  rest  on  the  mucous 
membrane  of  the  alveolus  or  palate,  such  as 
a  "  saddle  "  for  instance,  and,  indeed,  one  might 
almost  say  that  no  metal  of  any  sort  should  be 
allowed  so  to  rest,  although  other  writers 
advocate  it — explaining  that  the  metal  could 
be  fitted  so  closely  to  the  gum  surface  that  the 
fiuids  of  the  mouth  are  even  excluded.  It  is 
only  necessary  to  see  a  few  cases  fitted  in  this 
way  that  have  been  worn  for  a  short  time, 
to  realize  the  fallacy  of  the  argument ;  slight 
absorption  takes  place,  food  begins  to  collect, 
and  the  gums  then  become  inflamed  and  the 
piece  unhygienic  in  every  way. 

An  exception  to  this  rule  may  be  made  in 
cases  of  extension  of  the  bridge  behind  a  natural 
tooth  not  included  in  the  bridge,  by  means  of 
an  oval  wire,  and  carrying  a  facing  attached 
only  to  the  \\ire,  so  that  floss  silk  can  be  passed 
under  it  and  around  and  so  keep  it  clean ;  for 
instance,  a  posterior  bridge,  one  abutment  of 
which  is  the  first  premolar,  from  which  the 
extension  conies  around  the  canine  and  carries 
a  lateral  facing.     The  extension  bar  should  be 


605 


kept  well  free  from  the  tooth  that  it  encircles 
so  that  food  will  he  removed  by  the  tongue. 

In  removable  work  the  resting  of  metal  on 
the  mucous  surface  does  not  matter,  and  it  is 
an  additional  benefit  as  a  support  to  the  piece. 

Goslee  (5)  says,  referring  to  Saddle  Bridges 
in  connection  with  "  fixed  "  bridge- work — 

"  The  practicabihty  of  this  metliod  has  long 
been,  and  indeed,  perhaps  still  is,  a  somewhat 
debatable  question,  but  it  may  nevertheless  be 
safely  asserted  that  whUst  the  possible  virtues 
of  the  principle  involved  wUl  increase  or  dimuiish 
in  proportion  to  the  degree  of  accuracy  obtained 
in  the  adaptation,  the  utility  when  judiciously 
employed  is  unquestionable." 

And  again — 

"  Upon  the  removal  of  such  bridges  worn 
from  three  to  five  years  where  the  adaptation 
has  been  good,  the  surfaces  of  the  saddles  have 
been  found  clean  and  comparatively  free  from 
accumulations  except  some  little  exfoUated 
epithelium ;  the  patients  had  experienced  no 
particularly  unpleasant  taste  nor  offensive 
odours.  And  the  tissues,  while  presenting  a 
slightly  reddened,  somewhat  congested  appear- 
ance, due,  perhaps,  to  a  superficial  capillary 
stasis,  as  the  result  of  the  pressure,  indicated 
no  marked  evidences  of  soreness,  inflammation, 
hypertrophy,  nor  resorption.  Such  results 
could  only  be  expected,  however,  when  a  good, 
close  adaptation  without  irritating  influences 
existed." 

It  seems  to  the  writer  that  this  description 
of  a  piece  worn  "  from  three  to  five  years  " 
points  to  the  fact  that  the  conditions  found 
were  distinctly  mihygienic  and  extremely  un- 
desirable, and  that  they  show  the  advisability 
of  not  employing  saddles  in  fixed  bridge-work, 
rather  than  being  an  argument  in  favour  of 
so  doing. 

Relative  Value  of  Large  and  Small  Bridges. 
As  a  general  rule  it  is  better  to  make  two 
relatively  small  bridges  in  a  mouth  rather  than 
a  single  large  bridge,  but  the  operator  must,  of 
course,  be  guided  by  the  conditions.  A  root  not 
sufficiently  strong  as  an  abutment  by  itself 
becomes  a  very  useful  adjunct  to  a  large  bridge. 

Relative  Value  of  Bridges  and  Bridge-plates. 
Bridge-plates  or  saddles,  which  should  only 
be  used  in  removable  work,  often  give  greater 
strength  to  the  piece ;  for  instance,  a  bar  across 
the  palate,  uniting  two  saddle  bridges,  will  aid 
in  giving  strength  in  many  cases  of  shaLlo\\' 
bridges,  and  enable  simpler  forms  of  removable 
abutments  to  be  used.  Then  agam,  in  bridges 
from  canine  to  canine  in  the  maxilla  when  a 
V-shaped  arrangement  of  the  teeth  is  necessary, 
much  greater  strength  Ls  obtained  by  a  saddle 
over  the  alveolar  margin,   and  very  often  in 


these  cases  a  more  aesthetic  arrangement  of 
the  teeth  can  be  obtained. 

Variety  of  Abutment  Pieces,  and  Forms  of 
Anchorage. — The  chief  abutment  pieces  for  fixed 
bridges  are  the  all -gold  crown,  and  the  Rich- 
mond crown — the  Richmond  crown  may  be 
varied  by  having  only  a  half-band — ,  and  the 
"  porcelain-faced  "  crown. 

"  Pin  and  Plate  "  crowns  in  anterior  teeth  may 
be  employed  ;  they  are  not  nearly  so  satisfactory 
from  the  point  of  view  of  strength,  but  as  they  can 
be  easily  made,  and  with  the  certainty  of  show- 
ing no  gold  cervically,  they  have  their  uses.  In 
these  days  of  pressure-casting,  however,  such 
an  accurate  diaphragm  and  half -band  may  be 
made,  with  no  discomfort  to  the  patient,  and 
with  the  certainty  of  obtaining  a  good  fit 
medially  and  distally  (a  thing  that  Ls  difficult 
to  obtain  by  the  ordinary  method  of  making 
a  half-cap),  that  it  is  really  very  seldom  one 
would  be  justified  in  using  them. 

Another  form  of  anchorage  in  both  fixed  and 
removable  work  is  the  spur  resting  m  a  hole 
or  groove  ui  a  gold  fiUmg  or  cast-gold  inlay 
placed  in  the  abutment  tooth.  The  use  of  the 
spur  or  bar  built  into  a  gold  filling  is  highly 
unsatisfactory  and  practically  obsolete,  as  it  is 
almost  impossible  to  build  a  really  solid  filling 
around  a  spur  or  bar,  and  they  so  often  work 
loose.  The  iridio-platinum  bar  fittmg  mto  a 
slot  in  a  cast-gold  filling,  and  so  arranged  that 
it  "  locks  "  when  in  place,  is  an  excellent  form 
of  support  where  the  strain  is  not  too  great 
and  where  it  is  desirable  not  to  crown  the  whole 
tooth ;  this  is  more  particularly  used  in  remov- 
able work  and  is  so  much  simplified  by  the 
castmg  process.  It  is  of  great  use  in  those  cases 
where  one  abutment  is  a  shallow  tooth  and  does 
not  lend  itself  to  a  telescopic  cap. 

In  removable  work  the  best  forms  of  abut- 
ment are  the  telescopic  caps,  and  the  half- 
round  cap  and  split  pin. 

The  "  key  "  anchorage  ui  cases  of  shallow 
occlusion  is  very  useful. 

The  gold  inlay  as  an  anchorage  when  united 
to  a  cast  bridge  by  solder  is  of  considerable 
use  in  fixed  and  removable  bridges. 

Relative  Value  of  Banded  and  Non-banded 
Abutments. — In  all  cases  of  abutments  for 
bridge-work  the  banded  variety  is  preferable 
to  the  non-banded,  from  the  point  of  view  of 
strength.  It  is  undoubtedly  difficult  to  fit  in 
such  a  way  that  gold  does  not  show,  and  in 
process  of  time  there  is  apt  to  be  a  certain 
amount  of  recession,  which  wiU  expose  the  gold  ; 
this  is  the  chief  disadvantage,  bnt  the  amount 
of  recession  caused  by  the  band  diminishes  pari 
passu  with  the  accuracy  of  the  fit  of  tlie  band, 
and  if  it  were  possible  in  all  cases  to  have  the 
gold  extending  under  the  gum  only  to  the  exact 
extent  of  the  enamel  that  has  been  removed, 


606 


and  that  the  band  replaces,  this  recession  would 
liardly  ever  take  place  in  consequence  of  the 
band.  There  is  also  of  necessity  more  pain 
infhcted  in  fitting,  but  this  can  be  reduced  to 
a  minimum  by  careful  manipulation  and  by  the 
use  of  obtundents. 

A  half-band  is  the  next  best  thing  in  cases 
where  a  full  band  camiot  be  used,  and  in  the 
incisors  protects  the  root  from  the  direction 
of  the  greatest  strain. 

In  most  cases  a  banded  crown  can  always  be 
used  on  the  molars  and  premolars. 

"  Pin  and  plate  "  teeth  may  very  seldom  be 
used,  as,  for  the  same  reason  that  applies  to 
their  use  in  crown-work,  they  are  not  so  strong, 
and  their  weakness  is  accentuated  by  the  greater 
strain  brought  to  bear  in  bridge-work,  and  it 
is  only  in  the  cases  where  there  is  practically 
no  "  bite  "  that  they  can  be  used. 

In  removable  bridge-work  the  band  is  a 
necessity  for  really  good  work,  but  the  difficulty 
of  the  gold  showing  may  sometimes  be  got  over 
by  having  the  facing  fitted  over  the  inner  cap, 
and  just  resting  hghtly  on  the  gum,  providing 
it  does  not  make  the  tooth  seem  too  prominent. 
Li  a  fi.xed  piece  this  is  absolutely  inadmissible  : 
the  band  and  facing  must  always  be  flush. 

Relative  Value  of  Fixed  and  Removable 
Bridges. — There  can  be  little  doubt  that  a  well- 
made  removable  bridge,  built  on  the  proper 
lines  to  suit  the  case  in  hand,  is  far  superior  in 
most  cases  to  a  fixed  one  ;  it  is  true  that  some 
patientslike  so  much  the  idea  of  "  fixture  ",  that 
it  is  sometimes  difficult  to  make  them  see  the 
advantages  of  a  removable  piece,  but  this  diffi- 
culty can  almost  always  Ijc  overcome.  In  cases  in 
which  it  is  essential  to  make  the  work  removable, 
it  is  advisable  to  refuse  to  do  the  work  rather 
than  run  the  risk  of  failure  by  not  so  doing. 

The  two  main  advantages  of  a  removable 
bridge  are  the  ease  of  repair  and  the  greater 
longevity  of  the  piece  from  the  point  of  view 
of  the  alnitments  lasting  better,  and  the  chief 
disadvantages  are  the  greater  difficulty  of 
construction  and  the  longer  time  taken  and 
number  of  visits  that  a  patient  must  make. 
These  points  must  be  weighed  carefuUy  in  each 
individual  case,  the  jjatient's  temperament 
being  taken  into  consideration. 

With  regard  to  the  ease  of  repair,  an  accident 
may  happen  to  the  very  best-constructed  bridge 
— a  facing  may  break ;  but  if  removable  this 
is  easily  put  right.  Some  may  say  that  re- 
movable facings  do  away  with  this  difficulty — 
they  do  partially,  of  course ;  but  then  there  is 
always  the  fact  that  there  is  a  much  smaller 
selection  of  colour  in  removable  facings,  and 
this  is  a  great  difficulty  to  many  operators  and 
of  very  great  importance  for  the  aesthetic 
result.  It  can  be  got  over  by  making  special 
removable    facmgs    or    two-part    backings    for 


the  case  in  hand,  but  this  is  a  much  more 
lengthy  process,  and  cannot  always  be  used. 
However,  the  facing  question  is  not  the  most 
important  from  the  repairing  point  of  view ; 
it  is  this — that  sooner  or  later  in  most  mouths 
recession  of  the  gum  at  the  cervical  margins 
will  take  place.  Now  when  this  happens,  for 
exam{)le,  on  the  medial  surface  of  a  second 
lower  molar  abutment,  the  removable  bridge  is 
taken  off,  and  either  the  tooth  is  filled  or  the 
inner  cap  is  removed  and  repaired  or  a  new 
one  made,  and  the  piece  is  then  as  good  as 
before ;  and  it  must  be  remembered  that  the 
daily  (or  several  times  daily)  removal  of  the 
bridge  very  often  prevents  the  occurrence  of  caries 
in  this  position — the  patient  can  pay  particular 
attention  to  that  part  of  the  tooth  when  there 
is  recession,  and  it  can  be  kept  scrupulously 
clean.  In  a  fixed  piece  any  recession  of  the 
gum  in  this  position  means  certain  caries  at 
an  early  date,  and  when  it  has  taken  place  the 
whole  bridge  must  be  removed — a  difficult 
operation  and  one  that  means  that  in  many 
cases  the  bridge  is  rendered  useless,  and  a  new 
one  must  be  made  if  it  is  to  be  satisfactory. 

Then  again,  the  longevity  of  a  fixed  bridge  is 
probably  very  much  influenced  adversely  by  the 
fact  of  both  the  abutment  teeth  being  always  held 
firmly  in  one  position  and  of  having  no  move- 
ment at  all  apart  from  each  other.  In  the 
normal  condition  in  the  mouth  a  tooth  has  a 
certain  amount  of  rao\omcnt  in  its  socket,  and 
this  condition  of  individual  movement  is  more 
nearly  approximated  in  a  removable  bridge ; 
because,  when  the  piece  has  been  sprung  into 
j)lace  there  is  undoubtedly,  after  it  has  been 
worn  for  a  time,  a  certain  amount  of  movement 
of  the  outer  on  the  inner  caps — not  sufficient 
to  be  uncomfortable  or  insecure,  but  enough 
to  give  each  abutment  piece  a  small  amount 
of  play.  And  again,  by  leaving  it  out  at  night 
when  possilile,  the  roots  are  rested  and  the 
mucous  memljrane  is  refreshed  and  stinuilated 
by  being  left  uncovered  and  perfectly  clean — 
undoubtedly  a  very  important  point  to  be 
taken  into  consideration. 

The  cases  in  ^^■hich  a  fixed  bridge  is  perhaps 
preferable  to  a  removable  one  are  those  in  the 
front  of  the  mouth  consisting  of  one  abutment 
piece  and  one  facing,  with  a  spur  in  a  filling 
on  an  adjouiing  tooth.  Unless  two  abutment 
pieces  are  made  in  these  small  cases  they  are 
apt  to  work  loose  on  the  iimer  caps  and  be  a 
constant  source  of  aiuioyance,  and  the  employ- 
ment of  two  abutments  means  often  the  un- 
necessary mutilation  of  a  practically  sound 
tooth. 

IMPRESSIONS 

With  regard  to  impressions  in  bridge-work, 
one   thing   is   of   great    importance,    and   that 


607 


is  to  realize  that  a  plaster  impression  repays 
one  in  every  way  for  the  extra  time  em- 
ployed in  taking  it ;  there  is  absolute  accuracy 
and  no  chance  of  "  dragging  "  or  \\arping,  as 
with  modelling  composition ;  then  again,  the 
final  model,  on  which  the  piece  is  to  be  finished, 
can  be  made  from  an  imf)ression  and  bite  in 
one  piece,  ■with  the  certainty,  if  properly  done, 
of  a  perfectly  true  occlusion.  With  any  othei' 
material,  a  "  squash  bite  "  impression,  or  even 
one  taken  in  the  ordinary  way  in  a  tray,  is 
very  easily  distorted  in  removing  from  the 
mouth,  and  it  is  very  difficult  to  be  sure  that 
the  abutment  pieces  or  bands,  as  the  case  may 
be,  are  replaced  in  their  proper  position  in 
the  impression  before  casting,  when  they  have 
not  come  away  in  the  imjjression. 

For  instance,  supposing  composition  were 
used  in  a  case  of  two  gold  crowns  as  abutment 
pieces,  the  bands  of  these  crowns  are  put  in 
the  mouth  for  the  last  impression,  and  if  properly 
fitted  should  hug  the  roots  tightly ;  they  are 
also  contoured  ;  if  the  composition  comes  away 
leaving  the  bands  on  the  roots,  as  it  should  as 
a  rule,  it  is  i^ractically  impossible  to  replace 
the  bands  tightly  in  the  impression  owing  to 
the  dragging  of  the  material.  For  rough  models, 
of  course,  composition  is  very  useful. 

Some  ojierators  complain  that  a  bridge 
made  from  a  plaster  impression  goes  into  place 
in  the  mouth  \\ith  more  difficulty.  It  is  not 
easy  to  see  how  this  is,  for  the  bridge  either  fits 
or  it  does  not,  and  the  slight  shrinkage  of  the 
solder  is  allowed  for  by  the  natural  spring  of 
the  teeth  in  their  sockets ;  the  abutments  often 
require  a  little  touching  up  on  their  sides  to 
allow  the  caps  to  go  over  them,  but  after  that 
they  sliould  fit  snugly  into  place  under  the  gum 
with  the  aid  of  firm  pressure,  or  perhaj^s  a 
little  gentle  tapping. 

The  taking  of  plaster  impressions  for  ordinary 
work  is  described  elsewhere,  but  the  taking 
of  a  "  squash  bite  "  in  plaster  is  here  described 
as  being  chiefly  used  for  bridge-work. 

The  plaster  is  of  the  soft  variety,  and  coloured 
with  carmine  in  the  bulk ;  the  abutment  pieces 
being  in  the  right  position  on  the  roots,  the 
mouth  is  rinsed  with  mUk  of  magnesia,  thus 
facilitatmg  the  removal  of  the  plaster  from  the 
mouth.  The  plaster  is  now  mixed  to  the 
consistency  of  thick  cream,  in  water  to  which 
has  been  added  a  few  drops  of  eau  de  Cologne, 
and  a  pinch  of  salt  to  hasten  the  .setting. 

The  plaster  is  then  taken  on  a  broad  spatula 
(an  agate  one  is  best)  and  spread  over  and 
around  the  abutment  pieces  and  the  space  be- 
tween, and  on  the  adjoining  two  or  three  teeth, 
being  left  pretty  thick  along  the  palatal  aspect 
of  the  teeth.  The  patient  is  then  directed  to 
turn  the  tip  of  the  tongue  as  far  back  as 
possible  against  the  median  line  of  the  palate. 


and  at  the  same  time  to  close  the  teeth  tightly 
and  keep  them  closed.  More  plaster  is  then 
applied  along  the  buccal  aspect  of  the  teeth 
to  be  included ;  jjl^nty  of  plaster  everywhere 
facilitates  removal  and  the  reassemblmg  of 
the  fractured  pieces.  The  plaster  should  be 
mixed  to  such  a  consistency  that  by  the  time 
it  is  in  place  in  the  mouth  it  is  getting  hard, 
and  in  a  minute  or  t«o  is  ready  for  removal. 
Mixmg  the  plaster  in  warm  water  also  hastens 
the  settuig  and  is  pleasanter  for  the  patient. 

Wlien  the  surj)lus  plaster  m  the  bowl  breaks 
with  a  clean  fracture,  remove  the  impression 
from  the  mouth  in  as  few  pieces  as  possible, 
carefully  placing  the  pieces  m  order  on  a  piece 
of  blotting-paper. 

When  the  plaster  is  quite  hard,  and  before 
the  impression  has  dried,  rinse  in  water  and 
brush  away  carefully  with  a  camel's-hair  brush 
any  loose  pieces  adhering.  As  the  abutment 
pieces  will  probably  not  have  come  away  in 
the  impression,  clean  them  carefully,  place  in 
position,  and  put  the  pieces  of  the  broken 
impression  together,  waxuig  them  with  hard 
wax  at  points  not  required  on  the  model. 

Now  run  a  thin  film  of  pink  wax  inside  the  walls 
of  the  crowns  or  bands,  but  leaving  uncovered 
with  wax  an  area  of  the  under-surface  of  the 
cusps  of  the  crown  (or  of  the  flat  tojj  of  a 
removable  abutment).  The  edges  and  inner 
surface  of  the  band  portion  of  the  crowns,  to 
the  extent  of  about  the  thickness  of  thick 
note-paper,  should  be  scraped  free  of  wax. 

If  in  the  abutment  pieces  there  are  tubes  or 
pins,  these  should  also  be  waxed  over  with  a 
thin  film.  After  casting,  this  aUo«s  the  wax 
to  be  burnt  away,  and  the  abutment  pieces  can 
then  be  taken  off  the  model  and  replaced 
■ndthout  any  danger  of  getting  them  in  the 
^^■rong  position.  This  very  carejid  waxuig  of 
the  caps  before  casthig  cannot  be  emphasized 
too  strongly,  as  on  it  depends  largely  the 
accuracy  ■with  which  the  piece  will  go  mto 
position  m  the  mouth ;  the  necessary  removals 
of  the  piece  from  the  model  dining  the  makmg 
cause  a  certain  amount  of  "rubbing"  and 
accurate  waxmg  reduces  this  to  a  minimum. 

That  part  of  the  impressions  containing  the 
caps  should  now  be  varnished  until  glazed  with 
sandarac  varnish,  in  which  has  been  dissolved 
a  piece  of  "  indelible  '  pencil  sufficient  to 
colour  it,  and  which  has  been  diluted  onc-haLf 
with  alcohol  from  that  usually  supplied  by 
the  manufacturers. 

The  model  and  overbite  are  now  cast  and 
separated  in  the  ordinary  way.  The  abutment 
pieces  are  warmed,  and  removed,  and  the  wax 
is  cleaned  off — the  best  way  is  to  heat  the  crown 
several  times,  putting  it  on  the  model  each  time 
until  the  wax  on  the  model  and  cap  is  burnt 
away. 


608 


It  is  very  essential  that  all  the  details  that 
go  to  securing  a  good  model  should  he  faithfully 
adliered  to,  as  a  bridge  should  be  finaUy  waxed 
up  and  invested  straight  from  the  model,  and 
never  tried  in  the  mouth  just  before  investmg, 
as  is  so  often  done,  so  that  an  accurate  model 
is  all-important. 

Goslee  (4)  advises  that  in  all  cases  the  im- 
pression with  the  finished  abutment  pieces  in 
position  should  be  taken  in  plaster,  a  wax  bite 
being  also  taken  {i.  e.  a  ''  squash  bite  "  m  wax), 
and  that  the  model  and  articulating  model 
should  be  mounted  on  an  anatomical  articulator 
in  correct  occlusion  by  means  of  the  "  wax  bite  ", 
and  the  work  then  fuiished  in  the  ordinary  way. 

Li  cases  where  a  very  large  bridge,  or  a  series 
of  bridges  comprising  practically  aU  the  teeth, 
is  being  made,  thLs  method  is  necessary;  but 
in  case  of  a  bridge  of,  say,  three  or  four 
teeth,  or  a  small  bridge  in  the  incisor  region,  it 
is  distinctly  unnecessary,  and  is  inferior  to  the 
"squash  bite"  in  plaster  for  the  following 
reasons  : 

The  amount  of  the  lateral  movement  of  the 
mandible,  and  the  consequent  necessary  length 
of  the  cusps  of  the  bridge,  can  be  easily  noted 
in  the  mouth ;  and  if  it  is  allowed  for  in  the 
construction  of  the  bridge,  any  slight  shortenmg 
of  the  cusps  can  be  done  in  the  mouth  before 
cementmg  the  bridge.  By  the  other  method 
much  unnecessary  work  is  done  :  fu-stly,  the 
whole  of  the  teeth  must  be  included  in  the 
plaster  model,  as  otherwise  the  lateral  move- 
ments may  not  be  even  approximately  true, 
and  unless  the  path  of  the  condyle  is  taken, 
and  even  if  it  is  the  lateral  movements  are  only 
approximate;  then  the  "wax  bite  "  admits  of 
much  inaccuracy  in  cases  where  the  articulation 
is  abnormal — it  can  be  so  easily  adjusted 
wrongly  to  the  models  if  there  has  been  the 
slightest  distortion  of  the  wax  in  cooling,  and 
removal  from  the  mouth.  Then  again,  as  has 
been  pointed  out,  if  there  is  any  great  abnormal- 
ity m  the  bite,  a  bridge  should  not  be  constructed 
unless  this  can  be  remedied  by  cutting  down  the 
cusps  of  the  opposing  teeth,  or  by  crowning 
them,  or  otherwise  making  the  condition  as 
nearly  normal  as  possible.  If  there  is  any 
doubt  as  to  the  right  height  of  cusps,  etc.,  the 
finished  abutment  pieces  can  always — and  in 
some  cases  should — be  tried  in  the  mouth  and 
articulated  there,  and  the  final  model  taken 
with  them  in  position  on  the  roots,  the  dum- 
mies being  afterwards  fitted  and  soldered  with- 
out further  trial  in  the  mouth. 

DESCRIPTION  OF  MAKING  A  TYPICAL 
FIXED  BRIDGE 

In  order  to  describe  the  making  of  a  tyjjical 
fixed  bridge,  the  case  will  be  taken  of  a  mouth 


in  which  the  left  upper  premolars  have  been 
lost,  and  there  is  also  a  carious  first  molar, 
broken  away  distally  and  labially  to  below 
the  gum  margin,  and  a  carious  and  hoUow 
canine.  The  occlusion  is  normal,  the  lower 
premolars  not  having  elongated. 

It  is  jsroposed  to  construct  a  bridge  having 
a  Richmond  crown  abutment  piece  on  the 
canine,  a  gold  crown  on  the  molar,  and  two 
premolar  dummies  with  porcelain  faces. 

The  devitalization  of  teeth  and  treatment 
of  septic  pulps,  and  the  general  methods  of 
root-canal  treatment  are  dealt  with  elsewhere 
(Chapter  XXVII),  and  need  only  be  touched 
upon  here  in  so  far  as  the  j)rocesses  bear  upon 
actual  bridge -construction. 

With  regard  to  the  sealing  of  the  root-apex, 
it  is  best,  in  cases  in  which  the  canal  is  to  be 
used  for  a  pin  or  tube,  to  defer  the  sealing  until 
the  canal  has  been  partially  reamed ;  it  is  so 
much  easier  to  place  whatever  material  is  used 
(generally  gutta-percha)  at  the  extreme  end 
of  the  canal  after  it  is  enlarged,  and  fuial 
sterilization  where  necessary  can  be  better 
carried  out.  Also,  and  more  important,  there 
is  no  risk  of  removing  the  root-filling  during 
subsequent  reaming  for  the  pin  or  tube ;  theo- 
retically one  could  not  do  so  without  drilling 
through  the  apex,  but  practically  it  may  hap- 
pen, the  gutta-percha  for  instance  being  dragged 
away. 

A  rough  squash  model  and  "  bite  "  is  first 
taken  in  composition,  or  better  still  in  plaster ; 
this  is  useful  for  reference  during  the  work,  and 
in  cases  of  any  difficulty  as  to  methods  of  treat- 
ment it  is  advisable  to  study  the  model  before 
deciding  just  how  the  bridge  is  to  be  constructed. 

The  pulps  of  both  teeth,  if  alive,  having  been 
destroyed  and  removed,  or  if  dead  teeth,  the 
canals  having  been  cleaned  and  sterilized,  the 
roots  of  the  molar  are  fiUed  in  the  ordinary 
way,  the  tooth  is  cleared  of  caries,  and  a  tem- 
porary gutta-percha  filling  placed  in  it,  so  as  to 
force  the  gum  well  away  from  the  cervical  edges 
that  are  under  the  gum.  The  apex  of  the  canine 
is  then  sealed  temporarily  with  absorbent  cotton- 
wool dipped  in  antiseptic.  The  crown  is  cut  off, 
and  the  root  "  dressed  down  "  so  that  about 
one-sixteenth  of  an  inch  of  root  is  left  projecting 
from  the  gum.  The  root  is  then  dried  and 
the  absorbent  cotton  removed ;  a  very  fine 
flexible  broach  is  passed  to  the  apex ;  a  small 
piece  of  rubber -dam  having  first  been  placed 
on  the  shank  of  the  broach,  the  exact  length 
of  the  canal  is  then  measured  off  from  this  on 
the  shank  of  a  Beutelroc  or  similar  drill  by 
this  piece  of  rubber,  and  a  similar  length  also 
measured  off  on  graduated  sizes  of  other  drills, 
up  to  the  largest ;  by  this  means,  the  danger  of 
subsequently  perforating  the  apex  is  reduced 
to  a  minimum. 


609 


Successive  size  drills  are  then  used  in  the 
ordinary  way,  and  the  canal  is  enlarged.  It  is 
advisable,  after  the  first  three  or  four  drills 
have  been  used,  not  to  pass  the  others  quite 
to  the  apex,  a  sufiScient  enlargement  of  the 
canal  only  being  obtained  to  allow  of  the  apex 
being  easily  sealed  w-ith  gutta-percha.  The 
enlargement  must  be  made  gradually  tapering 
to  the  end ;  this  is  quite  easily  done  provided 
that  each  drill  is  only  slightly  larger  than  the 
preceding ;  but  should  too  large  an  increased 
size  be  used,  a  ridge  will  be  formed,  and  if 
there  is  any  curve  towards  the  end  of  the  root, 
it  is  then  extremely  difficult  to  pass  even  the 
smallest  drill  again  to  the  apex  (as  will  be  seen 
by  the  rubber  measurement),  and  the  risk  is 
run  of  a  faulty  root-filling. 

This  root-filling  is  now  inserted,  gutta-percha 
being  generally  chosen.  Care  must  be  taken 
to  use  only  just  enough,  as,  if  too  much  is  put 
in,  the  length  of  the  canal  is  diminished,  and, 
as  a  rule,  one  cannot  have  a  root-canal  too  long. 
One  thirty-second  to  one-sixteenth  of  an  inch 
of  gutta-percha  is  enough,  this  being  measured 
by  passing  up  a  drill  and  noting  the  difference 
in  length  before  and  after  filling. 

At  this  stage  gutta-percha  may  be  pressed 
well  over  the  root  surface,  and  held  in  place 
by  a  blunted  tin-tack,  or  a  pin  with  a  flat  disc 
attached,  passing  up  the  canal.  In  twentyrfour 
hours  the  gum  is  mcely  pressed  away  from  the 
root ;  a  novocaine  tabloid  is  then  ground  to  a 
powder  and  a  little  dabbed  between  the  gum 
and  the  tooth,  sufficient  to  prevent  the  pain 
incident  to  removal  of  the  enamel. 

The  next  step  is  the  "  coning  up  "  of  the 
canine.  Too  much  trouble  cannot  be  taken 
in  doing  this,  as  it  is  not  an  easy  thing  to 
prepare  a  root  perfectly  for  the  fitting  of  the 
band.  The  shape  of  the  teeth  seen  in  trans- 
verse section  at  the  gum  level  is  more  or  less 
the  same  in  each  individual  (see  Figs.  765  and 
766),  and  it  is  essential  to  have  a  clear  idea  of 
the  shape  of  a  given  tooth  from  this  aspect 
after  the  enamel  has  been  removed. 

In  the  removal  of  all  the  enamel  lies  the 
secret  of  making  a  well-fitting  band,  and  the 
omission  to  remove  all  is  the  chief  cause  of 
failure  at  this  step.  Once  this  is  realized  the 
main  difficulty  disappears,  and  it  is  surprising 
how  comparatively  easily  a  band  may  then 
be  made  to  hug  the  root  tightly,  so  that  an 
explorer  passed  beneath  the  gum  will  reveal 
no  greater  ridge  than  that  caused  by  the  thick- 
ness of  the  gold.  Root  preparation  is  tedious 
work  both  for  the  patient  and  operator,  but  its 
importance  cannot  be  insisted  on  too  strongly, 
and  the  extra  time  spent  in  properly  so  doing  is 
more  tluin  made  up  during  the  process  of  fitting 
the  band. 

The  removal  of  enamel  is  best  accomplished 
20 


by  means  of  heavy  "enamel  cleavers"  with 
curved  blades,  right  and  left,  cutting  on  one 
side  only,  and  having  short  thick  handles  that 
can  be  firmly  grasped  ;  the  rounded  edge  passes 
under  the  gum  margin  and  causes  little  or  no 
injury  to  the  tissues.     This  form  of  cleaver  was 


Fio.  765. — Upi^er ;  right  side. 

first  suggested  by  Peeso  and  is  undoubtedly 
the  most  useful.  Case's  enamel  cleavers  are  in 
addition  very  useful.  The  point  of  the  blade 
is  used   to    start    the    cleavage    by    forming  a 


Fig.  766. — Lower;  right  side. 

groove  or  cut  in  it,  and  then  bit  by  bit  it  is 
pulled  off.  Wlien  the  "  bulge  "of  the  enamel 
is  thick,  it  may  be  thimied  down  by  a  stone 
— this  greatly  facilitates  removal.  A  firm  sup- 
port for  the  thumb  or  fingers  must  be  got 
on  the  adjoining  tooth.  By  passing  the  blade 
of  a  spatula  under  the  gum  and  noting  whether 


610 


the  ridge  has  disappeared,  and  by  the  "  feel  " 
of  the  root  to  a  probe,  one  can  tell  when  the 
enamel  is  all  removed. 

The  enlargement  of  the  root-canal  is  now 
continued,  the  next  sizes  of  the  drills  are  used 
up  to  the  largest,  and  then  the  reamers,  enlarg- 
ing the  canal  sufficiently  to  enable  pin-wire 
(sile  3  Ash)  tempered  well  to  be  passed  up, 
giving  a  length  of  pin  as  much  more  as  possible 
than  the  length  of  the  facing  when  finished. 
In  a  canine,  pin-wire  size  (between  No.  3  and 
4  Ash)  may  be  employed,  but  care  must  be  taken 
not  to  weaken  the  canal  in  a  small  tooth. 
Iridio-platinum  (10%  iridium)  is  better  than 
gold  for  fixed  bridges ;  there  is  no  danger  of 
fusing  when  using  a  high  carat  solder,  and  a 
thinner  pin  with  equal  strength  may  be  used 
in  necessary  cases. 

The  Peeso  root  reamers  will  be  found  the 
most  useful,  as  the  tip  of  the  reamer  does  not 
cut,  there  being  a  small  thin  point,  which  acts 
as  a  guide  and  helps  to  prevent  cutting  through 
the  wall  of  the  canal,  and  it  is  impossible  with 
ordinary  care  to  go  through  the  apex. 

The  coning  up  of  the  molar  is  at  this  stage 
proceeded  with.  First,  the  occlusal  surface 
of  the  tooth  is  ground  freely  away  to  allow  for 
the  necessary  thickness  of  gold  cusps.  As  will 
be  seen  later,  these  cusps  are  made  solid  with 
gold  of  the  carat  and  constitution  of  coin  gold, 
so  that  plenty  of  space  must  be  allowed ;  the 
common  practice  of  allowing  only  sufficient 
room  for  cusps  of  about  No.  4  (Ash)  "  crown  " 
(22-carat)  gold,  reinforced  with  a  little  solder,  is 
entirely  wrong  ;  tliey  wear  through  very  quickly 
in  the  mouth  and  of  course  are  not  strong. 
The  objection  to  reinforcing  cusps  with  low 
carat  solder  to  obtain  the  required  strength  is 
that  if  any  grinding  has  to  be  done  in  the 
mouth  to  "adjust  the  bite,  and  it  sometimes 
happens  that  there  is  a  sort  of  "alternative" 
bite,  the  aesthetic  appearance  of  the  bridge  is 
impaired  by  the  discoloration  of  the  solder. 

In  preparing  the  waUs  the  procedure  is  some- 
what similar  to  that  for  the  preparation  of 
the  canine,  but  stones  are  more  freely  used,  and 
do  the  greater  part  of  the  work;  for,  as  the 
abutment  piece  on  a  molar  is  in  most  cases  a 
gold  crown,  as  much  of  the  walls  of  the  tooth 
as  possible  is  left  standing,  and  the  cleaving 
of  the  enamel  in  such  cases  without  its  being 
thumed  down  is  almost  impossible. 

Now,  were  the  teeth  used  as  abutments  always 
parallel,  the  removal  of  the  enamel  would  leave 
the  walls  in  proper  alignment;  but  in  many 
cases,  when  it  is  desired  to  put  a  bridge,  there 
has  been  more  or  less  tilting  of  the  teeth, 
especially  in  the  molar  region.  It  will  be  easily 
seen,  therefore,  that  if  the  walls  of  the  prepared 
root  and  the  root -canal  are  not  parallel  or 
slightly  less  than  parallel,   the   finished   piece 


would  not  go  into  place ;  hence  this  must  be 
kept  in  mind  during  the  process  of  coning  up. 
By  merely  examining  the  teeth  in  the  mouth, 
the  amount  of  removal  necessary  is  very  diffi- 
cult to  estimate,  so  that  the  model  must  there- 
fore be  carefully  examined  in  order  that  a 
general  idea  may  be  obtained.  Much  time  is 
saved  by  so  doing,  and  where  a  molar,  for 
instance,  leans  considerably  in  any  direction, 
a  bold  slice  of  tooth  may  be  cut  off  by  a  plane- 
faced  disc,  and  the  tooth  roughened  up  into 
its  approximate  shape.  Help  is  obtained  in 
getting  alignment  by  bending  a 
piece  of  soft  wire,  of  a  size  that 
easily  fits  the  canal  of  an  incisor 
or  premolar,  into  such  a  shape 
that  the  two  ends  will  be  parallel  jf^.^  767. 

(see  Fig.  767),  one  end  being 
placed  in  the  canal  of  the  first  abutment  tooth 
and  the  other  in  or  against  the  second  abutment 
tooth.  German  silver  plate  cut  into  narrow 
strips  and  bent  to  suit  the  particular  case,  is 
useful  for  molars  and  premolars  when  shell 
cro\vns  are  to  be  used. 

In  the  bridge  under  descrij)tion  the  molar  is 
so  shaped  that  its  walls  are  nearly  parallel 
with  those  of  the  canine  and  its  root-canal. 
To  get  exact  parallelism  is  impossible,  and 
indeed  not  desirable,  for  by  making  the  walls 
slightly  less  than  parallel,  a  shght  natural 
spring  is  obtained  when  the  finished  piece  is 
put  into  place. 

The  teeth  are  now  ready  for  the  fitting  of 
the  bands.  The  rough  fitting  is  best  done  on  a 
model ;  it  saves  the  patient  considerable  dis- 
comfort and  pain  and  saves  the  operator's 
time,  as  it  can  he  done  by  the  mechanic. 


Flu.  7I3S. 

The  method  is  as  follows  :  A  piece  of  ordinary 
modelling  wax  is  made  into  a  cone  about  an 
inch  long,  and,  when  at  a  temperature  slightly 
above  that  of  an  ordinary  warm  room,  the 
point  of  the  cone  is  passed  07ice  through  the 
flame  of  the  spirit  lamp  and  then  placed  in 
the  centre  of  the  root ;  continuous  pressure  is 
exerted  against  the  root  and  gum  until  the 
wax  gives  and  spreads  over  the  surface,  when 
the  outline  of  the  root  is  shown  on  the  wax 
on  removal.  In  the  case  of  the  molar,  one 
side  being  below  the  surface  of  the  gum,  par- 
ticular attention  must  be  paid  to  getting  this 
edge  defined  in  the  wax  :  by  placing  the  wax 
near  the  edge  in  the  first  instance  and  then 


611 


pressing,  this  result  will  be  obtained.  This  is 
done  both  for  molar  and  canine.  Each  wax 
impression  is  cast  separately  in  plaster,  and 
when  it  is  quite  hard,  the  base  of  the  model  is 
warmed  and  the  wax  removed. 


Fig.  7G9. 

The  outline  of  the  root  is  now  seen  clearly 
in  the  plaster,  even  the  part  that  is  under  the 
gum  in  the  mouth  (see  Fig.  768). 

A  fine-pointed  instrument  is  now  taken,  and, 
by  keeping  it  flat  against  the  root  and  in  the 
same  plane,  the  plaster  is  gradually  "  pared  " 
away,  forming  a  groove  all  round  the  root  to 
the  depth  of  about  a  thirty-second  of  an  inch. 
The  plaster  base  is  then  cut  away  all  round  the 


Fig.  770. 


root  until  the  bottom  of  the  groove  is  reached, 
when  the  model  will  be  as  in  Fig.  769,  i.  e.  one 
thii'ty -second  of  an  inch  more  from  the  model 
than  when  first  cast.  If  the  root  in  the  mouth 
has  been  properly  "  coned  up  '",  this  model  will 
pretty  faithfully  represent  the  condition  in  the 
mouth,  with  that  part  of  the  root  under  the 
gum  exposed. 

These  models  are  dried  slowly  overnight, 
and  then  coated  with  sandarac  varnish 
several  times  (the  vaniish  usually  sup- 
plied should  be  diluted  one-half  with 
alcohol),  the  hollow  parts  of  the  roots 
are  filled  flush  with  hard  wax,  and  they 
are  then  ready  for  fitting  the  bands. 

Measurement  is  taken  with  a  thin  strip  of 
annealed  "  brush  copper  "  (which  can  be  got 
at  an  electrician's)  and  the  length  marked  out 
on  the  gold. 

Gold  of  approximately  the  same  carat  and 


fine-fitted  and  let  down  so  that  it  follows  the 
gum  line.  Twenty-one  carat  solder  is  used 
here  if  the  soldering  method  is  employed.  The 
gold  is  cut  from  the  main  piece  on  a  slant  (see 
Fig.  770)  so  that  when  fitted  it  flares  out  all 


round  and  gives  the  commencement  of  the 
contour.  If  the  cone  is  made  from  a  curved 
piece  of  gold  (see  Fig.  771),  great  care  must 
be  taken  to  see  that  the  measurement  is  accur- 
ate, as  it  is  more  difficult  to  obtain  on  the  curve. 
Only  a  very  slight  "  flare  "  must  be  given,  as 
the  remaining  necessary  contour  is  done  in  the 
mouth  by  "  contouring  pliers  " ;  this  contour- 


B 


■C 


ing  only  applies  to  the  molar  band,  the  canine 
not  requiring  it  (see  Fig.  772).  The  sweating 
of  the  edges  together  instead  of  soldering  is 
desirable,  and  may  be  described  here.  The 
end  of  the  band  A  (see  Fig.  773),  after  being 
bent  roughly  round  the  plaster  root,  is  chamfered 
at  B,  to  about  the  extent  of  the  thickness  of 
the  gold.     At  C  it  is  also  chamfered,  but  on 


Fig.  771. 

hardness  as  coin  gold  rolled  into  plate  form  jiji^ 
inch  thick  is  the  best  to  use  (about  size  4,  Ash) ; 
it  is  hard  and  a  good  colour,  and,  as  will  be  seen 
later,  solders  that  work  well  with  it  can  be  made 
with  the  scrap.  A  piece  of  the  right  length 
having  been  cut  off,  and  of  sufficient  depth  to 
allow  for  fitting,  it  is  annealed,  bent  round  the 
model,  and  either  soldered  or  sweated,  and  then 


the  reverse  side.  These  ends  are  then  "  sprung  " 
against  each  other  into  perfect  contact  all  along  ; 
to  do  this  only  requires  a  little  knack,  straight 
ends  to  the  band,  and  perfectly  flat  bevels  of 
the  same  width,  made   by  a  flat  fine-cut  file. 


61i 


A  small  amount  of  "liquid  flux"  (sorosis  is 
one  of  the  best  varieties)  is  then  run  between 
the  ends,  and  the  point  of  the  blowpipe  applied 
to  the  gold  at  the  edge  that  is  not  going  to  be 
fitted  to  the  root  (see  Fig.  774),  and  as  soon  as  the 
gold  "sweats  "  at  this  point  the  flame  is  run 
firmly  along  the  line  of  junction,  just  as  if 
there  were  solder  there,  until  the  metal  fuses 
all  along.  A  small  pointed  blue  flame  {and  no 
draught  of  any  sort  to  divert  it)  is  necessary, 
and  the  gold  must  be  well  fused  at  the  point  of 
commencement,  and  the  whole  thing  done 
with  one  sweep  of  the  flame ;  otherwise  oxida- 
tion takes  place  and  the  band  has  to  be  carefully 
pickled  and  refluxed  before  the  edges  can  be 
further  united.  The  ends  need  not  be  "  cham- 
fered ",  but  it  gives  a  much  better  finish  if 
done,  as  little  or  no  filing  is  necessary. 

Both  bands  being  fitted  to  the  model,  they 
are  transferred  to  the  mouth  and  fine-fitted  to 
the  roots.  If  the  previous  stages  have  been 
carefully  done  this  will  be  a  comparatively 
simple  matter,  and  they  should  be  fitted  up 
under  the  gum  to  the  extent  of  about  a  thirty- 
second  of  an  inch ;  if  anything,  they  should  be 
fitted  on  the  tight  side  to  the  model,  as  they  can 
then  be  slightly  enlarged  if  necessary  at  the 
cervical  edge,  in  fitting  to  the  mouth,  by  means 
of  stretching  (contouring)  pliers  or  by  means  of 
a  small  anvil  and  hammer. 

The  molar  band  is  now  pressed  with  the 
fingers,  while  on  the  root,  until  it  is  somewhat 
the  shape  of  a  first  molar 
tooth,  and  not  merely  a  round 
ferrule  (in  tran.sverse  section 
like  Fig.  775),  and  it  should 
then  be  contoured  with  Peeso 
contouring  pliers  (short 
heavy-beaked  pliers,  which 
stretch  the  gold)  untO  it  is 
in  proper  contact  with  the  second  molar. 

Tliis  proper  contact  and  contouring  is  of 
great  importance,  firstly,  for  the  aesthetic  effect, 
and  secondly,  and  more  important,  for  the 
proper  preservation  of  the  inter-dental  space ; 
by  shaping  the  band  and  contouring  it  carefully, 
and  by  selecting  and  applying  the  right  sort 
of  cusps  or  "top",  the  natural  shape  of  the 
tooth  can  be  faithfully  reproduced.  The  band 
should  be  contoured  exactly  to  touch  the 
contiguous  tooth  at  the  normal  point  of  contact 
of  the  natural  teeth,  and  to  extend  a  little 
beyond  it ;  then  by  "  pinching  "  the  edge  of 
the  band  all  round,  this  extended  portion  only 
is  brought  away  again  from  the  contiguous 
tooth,  so  that  when  the  cusp  is  soldered,  the 
actual  contact  point  need  not  be  interfered 
with  during  filing  up  and  polishing,  as  the  part 
of  the  band  immediately  below  the  junction 
with  the  cusp  will  be  known  to  be  contact 
point  and  can  be  left  severely  alone,  with  the 


o 


Fig. 


certainty  that  when  the  bridge  goes  into  place 
this  most  important  adjustment  will  be  right 
(see  Fig.  776). 

The  proper  alignment  of  the  pin  and  two 
bands  must  be  here  carefully  noted  in  the 
mouth.  The  band  and  root  of  the  canine  are 
now  cut  down  labially  by  root-facers  (Peeso), 
so  that  (when  the  "top"  is  soldered  on)  the 
surface  of  the  gold  labially  is  just  below  the  gum, 
and  the  band  is  left  standing  about  one-sixteenth 


B' 

Fig.  770. — A,  Contact  point;  B,  Edge  of  band. 

of  an  inch  above  the  gum  on  the  palatal  side  ;  the 
band  is  then  taken  off  the  root  and  filed  absolutely 
flat  (in  a  slanting  plane)  on  that  side  on  which 
the  "  top  "  is  to  be  placed,  and  then  replaced  on 
the  root ;  it  will  now  appear  in  vertical  section 
as  in  Fig.  777,  the  dotted  line  representing  the 
"  top  ",  which  will  be  put  on  presently. 

The  molar  band  is  filed  flat  on  the  edges  on 
which  the  cusps  are  to  go,  and  a  space  sufficient 
for  the  thickness  of  the  cusps  left  between  it 
and  the  opposing  teeth 
(note  previous  remarks 
as  to  contact  point). 

The  canine  band  is 
now  made  into  a  cap  as 
for  an  ordinary  Rich- 
mond crown,  the  top 
being  sweated  or  sol- 
dered on  (if  soldered, 
21 -carat  must  be  used) ; 
the  top  must  be  of 
slightly  thicker  gold 
than  for  the  band,  viz., 
yi^jy  inch,  (about  size  5, 
Ash),  to  allow  for  any 
slight  filing  flat  later  on 
(in  order  to  get  an  easy 
adaptation  of  the  base  of  the  facing  when  it 
comes  in  contact  with  the  cap),  in  case  there  is 
any  warping  during  the  sweating  of  top  to 
band. 

In  sweating  the  top  on,  care  must  be  taken 
that  the  band  and  the  piece  of  gold  for  the  top 
are  flat,  and  so  come  in  absolute  contact  all 
round  (the  depots  supply  a  small  swager  or 
"  plunger  "  for  flattening  small  pieces  of  gold 
for  this  purpose).  The  top  is  held  in  iridio- 
platinum-boaked  pliers  at  the  extreme  edge, 
plenty  of  surplus  being  allowed ;  the  band  is 
dipped  in  liquid  flux  and  placed  on  it,  when 
they  will  be  in  absolute  contact  everywhere,  and 
they  are  then  held  over  a  Bunsen  burner  flame 


Fig. 


613 


(see  Fig.  778,)  the  points  of  the  phers  being 
brought  to  a  red  heat  first,  so  as  not  to  absorb 
heat  when  the  actual  sweating  takes  place. 
As  the  gold  is  heated  to  the  required  degree,  the 
corners  of  the  square  "  top  "  begin  to  curl  up, 
and  just  at  that  moment  the  gold  is  given  a 
"  dip  "    into   the    flame,    when   the   band   and 


Fig.  778. 

"  top  "  will  be  seen  to  fuse  together  just  as  if 
there  were  solder  between. 

It  is  then  trimmed  and  placed  on  the  root, 

and  a  pin  is  fitted  and  soldered  in  the  ordinary 

way  with  21 -carat  solder,  care  being  taken  to 

bend  the  pin  before  soldering 

it,  so  that  it  will  not  have  to  be 

ground  away  when  the  facing 

is  fitted ;    as    much    room   as 

possible  must  be  left  for  the 

facing  by  this  bending,  as  it  is 

often  difficult  to  get  room  for 

both    pin     and    facing.      (See 

Fig.  779.)     This  being  done,  it 

is  replaced  in  the  mouth,  and 

another  jjlaster  model  is  taken 

with  both  cap  and  the  molar 

band  in  position. 

The  molar  band  is  now  made  into  a  finished 

crown  by  the  following  method. 

A  molar  crown  die  is  chosen  from  an  assort- 
ment, which  it  is  desirable  to  have,  and  the 
method  of  making  these  dies  will  be  here 
described  :  An  extracted  molar  tooth  with 
crown  surface  intact  is  selected,  and  with  a  saw 
the  cusps  and  a  little  less  than  half  the  crown 
are  cut  off  (see  Fig.  780).  This  half  tooth  is  then 
placed  in  a  "  Badcock  "  water  swager,  and  a 
matrix  in  thin  copper  made,  appearing  as  in 
Fig.  781.     Into  this  copper  matrix  is  flowed  soft 


Fig.  779. 


solder,  the  surplus  edges  are  cut  off,  and  the 
surface  is  filed  quite  flat ;  it  will  then  appear 
as  in  Fig.  782.  A  large  selection  of  molar  and 
premolar  dies  should  be  made  and  kept  ready. 
To  return  to  making  the  gold  top  :  A  die  is 
selected  large  enough  to  be  in  contact  with 
the  gold  band  at  all  points  (a  little  overlapping 


Fig.  780. 

does  not  matter  at  all),  and  more  or  less  right 
as  to  the  bite  (as  seen  by  the  plaster  model). 
This  die  is  placed  in  the  Badcock  swager  and 
the  same  process  gone  through  as  was  employed 
in  making  the  copper  matrix,  oifly  pure  gold 
(thickness    ixnin)    '^    "^^^ !    ^    gold    matrix    is 


thus  obtained.  This  matrix  is  painted  with 
whiting  on  its  under-surface  (or  embedded  in 
plaster  and  sand)  and  placed  on  a  soldering 
block  (see  Fig.  783).  The  same  gold  as  is 
used  for  making  a  band  is  fused  into  about 
six  or  nine  separate  pellets,  each  about  twice 


^^ 


Fig.  782. 
A,  Copper  matrix ;  B,  Soft  sokier. 

the  size  of  a  pin's-head,  and  these  pellets  are 
placed  in  the  matrix  (see  Fig.  784).  A  steady 
whitish  flame  is  played  on  the  pellets  from 
directly  above  (not  at  an  angle)  until  the  pellets 
begin  to  melt  and  ''  settle  "  into  the  matrix, 
making  one  solid  piece.  No  flux  is  used  at 
first,  but  towards  the  end  a  little  may  be  used, 
and  care  must  be  taken  not  to  overheat  and  fuse 
the  pure  gold.  It  is  not  very  difficult  to  do, 
and  with  a  little  practice  may  be  done  quite 


614 


quickly,  but  if  once  the  matrix  is  fused  the  whole 
thing  is  spoiled.  The  surj)lus  gold  matrix  is 
cut  off,  and  the  bottom  filed  absolutely  flat  by 
drawing  it  along  a  fine-cut  file.  Pressure-casting 
has  of  course  rendered  this  method  much  less 


C 

Fig.  783. 

A,  Gold  Matrix  embedded  in  B,  Investment  material ; 

C,  Soldering  block. 

useful  than  it  was,  but  it  is  still  one  of  the  quickest 
ways  of  making  the  cusps. 

The  cusps  and  band  are  now  wired  together 
and  fluxed,  a  very  small  piece  of  21 -carat  solder 
is  placed  in  the  inside,  and  the  whole  held  over 


Fig.  785. 


Fig.  784. 

the  Bunsen  until  the  solder  fuses,  appearing 
now  as  Fig.  785.  The  surplus  cusp  is  cut  off 
(see  dotted  line.  Pig.  785),  the  crown  placed  on 
the  model,  and  the  occlusion  adjusted  by  cut- 
ting away  the  cusp.  Wlien  this  has  been  done, 
and  after  the  final  polishing, 
there  will  be  very  little  left 
of  the  pure  gold  matrix,  and 
a  crown  is  thus  obtained  all 
of  the  same  gold — band  and 
solid  cusps.  Any  further 
carving  of  the  gold  cusps 
may  be  done  with  stones  and 
finishing  burrs. 
The  next  step  is  the  selection  of  suitable 
facings  as  to  colour  and  size.  That  part  of 
the  cap  anterior  to  the  pin  is  ground  perfectly 
flat  (if  any  solder  has  got  on  it),  and  the  canine 
facing  fitted  first  and  waxed  temporarily  into 
place ;  the  premolars  are  next  fitted  to  the 
gum  so  as  to  rest  lightly  on  it  at  their  cervical 
edges,  but  they  must  neither  touch  each  other 
nor  the  abutment  pieces  on  either  side ;  they 
are  held  in  place  with  wax,  and  a  plaster  wall 


is  built  up  on  the  buccal  side  to  hold  them  and 
the  canine  facing  in  position.  When  the  plaster 
is  hard,  the  facings  are  removed,  and  the  occlusal 
ends  of  the  premolar  ones  ground  off  about  one 
tliirty-second  of  an  inch  at  an  angle  of  75°  with 
the  back  of  the  facing  (see  Fig.  786).  The  occlusal 
bevel  of  either  facing  should  not  be  higher  than 
the  other.  The  facings  of  the  premolars  are  then 
backed  with  platinum  about  y^u  inch  thick, 
by  placing  the  platinum  on  a  little  block  of 


Fig.  780. 


Fig. 


"  india-rubber  "  and  pushing  the  pins  through, 
and  then  conforming  it  to  the  facing  by  bending 
over  the  pins,  flowing  a  little  wax  on  to  the 
platinum,  and  pressing  with  the  fingers  until 
the  wax  is  hard.  The  backing  should  extend 
just  over  the  edge  which  has  been  ground  to 
fit  the  gum,  and  be  continuous  with  the  occlusal 
bevel  (see  Fig.  787).  Gold  camiot  be  used  in 
this  way  for  backing,  as  sufficiently  thin  gold 
would  be  in  danger  of 
fusing  during  soldering. 
On  the  side  they  should 
touch  each  other  and  the 
abutment  pieces.  The 
canine  facing  is  backed 
in  the  same  way,  only 
the  backing  is  extended 
beyond  the  tip  (but  not 
bent  over  it),  and  is  fiush 
with  the  flat  under- 
surface  that  fits  on  the 
cap  (see  Fig.  788).  If  it 
is  then  waxed  accurately 
in  place  on  the  cap,  two 
perfectly  flat  surfaces  are 
in  contact,  and  after 
soldering,  the  contraction  during  cooling  will 
cause  the  facing  to  be  as  in  Fig.  780,  leaving 
a  very  unsightly  space  (in  the  illustration  the 
space  is  exaggerated  to  show  what  is  meant) ; 
therefore  in  waxing  the  facing,  just  before  the 
wax  is  cool,  lever  it  ever  so  slightly  away  from 
the  cap  at  the  back,  as  in  Fig.  790,  and  the 
result  will  be  that,  after  soldering,  the  facing 
and  cap  will  be  in  exact  contact  (see  Fig.  791). 
The  plaster  supjjort,  which  is  now  put  back, 
will  just  have  to  be  altered  a  little  to  allow 
for  this  ;  the  premolar  facings  are  put  in  place, 
a  piece  of  oiled  paper  is  placed  on  the  cast, 


615 


and  all  are  waxed  firmly  together,  the  wax  bemg 
kept  liigh  enough  to  allow  the  cusps  of  the 
premolars  to  be  put  on.  Suitable  cusps  are 
then  made  in  the  same  gold  by  the  method 
described  for  making  the  top  of  the  molar  abut- 
ment piece,  and  these  cusj)s  are  then  ground 


Fig.  789. 


Fig.  790. 


or  filed  to  fit  the  bevel  on  the  facmgs  (see  Figs. 
792,  793),  the  same  space  being  left  for  the  con- 
traction of  the  solder  as  was  done  in  the  case 
of  the  canine  and  its  cap. 

All  the  parts  being  now  as- 
.sembled,  viz.  the  canine  cap 
and  facmg,  the  dummy  facings 
backed  and  waxed  up  with 
their  gold  cusps  in  position, 
and  the  molar  crown  abut- 
ment piece,  and  all  firmly 
united  with  hard  wax,  the 
piece  is  invested  in  plaster  and 
sand  (two  parts  sand  and  one 
part  plaster),  the  facings  having 
first  been  pamted  with  whiting 
to  keep  the  surfaces  from  being 
roughened,  and  is  then  soldered 
in  the  ordinary  way  with  20- 
carat  solder. 

In  investing,  only  an  amount 
of  investment  sufficient  for 
strength  is  used,  and  the  sides  of  the  mvest- 
ment  are  pared  flat  so  that  it  can  be  more 
easily  tipped  in  any  direction  required  during 
soldering  ;  soldering  is  done  on  an  iron  "  grill  " 
on  a  small  gas  "plate-heater",  i.e.  the  piece 
is  not  removed  from  the  heater  to  a  soldermg 
block  to  do  the  actual  soldering ;  it  is  much 
easier  to  keep  the  piece  up  to  the  required 
degree  of  heat  on  a  heater,  with  the  gas  lighted 


Fig.  791. 


only  so  much  as  will  not  interfere  with  the 
flame  of  the  blow-pipe. 

It  is  better  not  to  wash  out  the  wax  with 
hot  water,  Init  merely  to  heat  up  until  the  bulk 
of  the  wax  can  be  removed  with  a  spatula,  and 
then  allow  the  remainder  to  burn  off  in  the 
further  process  of  heating  up. 

Wien  the  mvestment  is  partially  dried,  it  is 
dusted  with  powdered  borax,  and  the  solder 
applied  in  the  ordinary  way,  and  then  the 
heating  up  and  soldering  are  continued.  With 
a  high-carat  solder  it  is  unnecessary  to  use  pieces 
of  metal  across  the  joints  in  soldering,  and  the 
necessary  thickness  of  solder  at  the  proper 
points  should  be  obtained  by  tilting  the  invest- 
ment, and  draw  ing  the  solder  w  here  it  is  wanted 
by  means  of  the  flame. 

A  few  small  pieces  of  solder  should  be  placed 
in  the  inaccessible  places  before  starting  to 
solder,  and  care  should  be  taken  to  see  that 
these  are  thoroughly  fused  to  commence  with. 
It  does  not  matter  how  quickly  the  investment 
is  cooled  down  after  soldering.  In  "  finishing 
up  ",  revolving  stones  on  the  dental  handpiece 


Fig.  792. 


Fig.  793. 


are  used  to  do  the  fuie  finishing,  and  the  wheel 
is  revolved  from  the  gold  to  the  porcelam. 
Polishing  is  done  with  discs  and  buff-wheel  on 
the  lathe  in  the  ordinary  way. 

An  excellent  way  of  makuig  suitable-sized 
felt  wheels  for  polishing  on  the  lathe  is  as 
follows  :  A  broad  felt  wheel  is  taken  and  cut 
into  four  slices  by  holding  the  point  of  a  very 
sharp  knife  against  it  while  revolving  on  the 
lathe ;  it  is  then  dipped  into  shellac  dissolved 
in  alcohol,  and  taken  out  immediately  and  dried 
thoroughly  on  a  glass  slab;  it  is  then  "trued 
up  "  on  a  lathe  with  a  piece  of  flat  wood,  and 
coned  with  a  sharp  knife,  the  flame  of  a  blow- 
jDipe  being  kept  on  the  wheel  to  soften  it  while 
being  "  trued  up  ".  This  makes  a  hard  wheel 
with  a  narrow  edge,  which  will  go  in  between 
the  cusps  and  narrow  places,  and  will  only 
polish  where  it  is  required. 

An  extra  finish  may  be  given  to  a  Ijridge  by 
filling  \\\y  the  spaces  between  the  facings,  and 
between  the  facmgs  and  abutment  pieces,  with 
pure  gold,  i.  e.  by  making  an  ordinary  gold 
filling  with  "  mat  "  gold  at  these  points ;  as 
a  rule  there  is  sufficient  hold  for  the  gold  when 
the  bridge  comes  out  of  the  investment,  but 
to  make  quite  sure  of  the  hold  the  sides  of  the 


616 


facing  may  be  ground  slightly  just  before 
waxing  up,  so  as  to  give  a  slight  undercut  at 
these  points  when  soldered.  This  method 
makes  a  very  beautiful  finish  to  a  bridge. 

Post  for  Crown-  and  Bridge-work. — Mention 
may  be  here  made  of  a  post  for  crown-  and 
bridge -work,  suggested  by  George  Brunton  of 
Leeds  (1),  and  described  by  him  as  follows — 

"  The  ijost  is  made  taper,  hollow,  and  open  in 
front  and  at  the  labial  aspect,  the  taper  f)0st 
fits  into  a  correspondingly  taper  hole  in  the  root, 
and  the  hole  is  notched  with  a  \\heel  burr 
opposite  the  opening  in  the  post.  Wlien  setting 
the  crown  or  bridge  the  hollow  post  and  the 
notched  hole  in  the  root  are  filled  with  cement, 
and  when  set  the  post  is  firmly  locked  in  the 
root,  and  rotation  is  prevented. 

"  The  advantages  from  the  use  of  this  post 
are  great  strength,  simplicity  of  construction, 
and  easy  removal  when  necessary.  The  great 
superiority  of  this  form  of  post  to  operators 
lies  in  the  fact  that  it  can  be  used  in  roots 
that  are  not  parallel.  Should  a  post  break, 
and  have  to  be  removed,  it  is  very  easy  to 
do  so  by  drilling  out  the  cement  from  the 
inside  of  the  hollow  post  at  the  back  or  lingual 
aspect.  It  is  then  easy  to  force  in  the  two  halves 
of  the  post,  and  remove  it.  There  is  thus  no 
weakening  of  the  root  by  the  use  of  the  trephine 
or  drilling  around  the  post  to  loosen  it.     This 


method  leaves  the  root  ready  for  the  insertion 
of  a  new  post.  The  construction  is  very  simple, 
requiring  only  such  tools  as  are  to  be  found  in 
any  workshop,  namely,  a  hand-vice,  taper  man- 
drel, shears,  a  small  anvil,  hammer,  and  file." 

The  British  Dental  Journal  says  of  this  post  : 
"...  The  interesting  point  of  novelty 
consists  in  the  abandonment  of  any  necessary 
attachment  by  adhesion  of  cement  between  the 
external  surface  of  the  post  and  the  internal 
walls  of  the  root -cavity,  dependence  being  placed 
ujJon  the  keying  of  the  cement  in  the  interior 
of  the  post  with  the  notched  position  of  the  root 
interior.  Should  this  in  use  prove  to  be 
sufficient  in  strength,  it  would  become  almost 
impossible,  in  silting,  to  force  any  excess  of 
cement  into  the  apical  foramen,  and  the  sheet 
metal  used  need  not  only  be  quite  thin,  but 
also  perfectly  smooth.  There  can  be  no  doubt 
about  the  novelty  and  great  mechanical  interest 
of  this  device,  especially  where,  as  in  all  porcelain 
bridge- work,  absolute  inflexibility  is  a  requisite, 

"  It  is  obvious,  however,  that  the  special 
features  of  the  post  are  only  developed  when 
the  most  perfect  accuracy  of  adjustment  in 
direction  is  secured.  Though  failing  this,  with 
provision  made  for  a  surrounding  of  cement  and 
inserted  as  the  usual  forms,  it  still  appears  to 
have  conspicuous  advantages  over  the  other 
well-known  tjrpes." 


CHAPTEII    XXXYIII 


BRIDGE-WORK     {continued) 


DESCRIPTION    OF    MAKING    A    TYPICAL 
REMOVABLE    BRIDGE 

Canine  to  molar.  Half-cap  and  split  piu  on 
canine  and  telescope-cap  on  molar. 

The  preparation  of  the  abutments  is  the  same 
as  described  in  the  making  of  a  fixed  bridge, 
but  even  greater  care  must  be  taken  in  getting 
the  proper  alignment.  Gold  of  the  same  carat 
and  hardness  as  coin  gold  is  the  best  to  use. 
crown  gold  (22-carat)  being  too  soft. 

The  canine  band  is  first  fitted,  having  plenty 
of  surplus  and  having  the  sides  slightly  less 
than  parallel,  and  quite  smooth  and  even  from 
the  top  to  the  bottom  edge  (».  e.  keep  the  beaks 
of  the  j)liers  embracing  the  full  length  of  the 
gold  in  bending  up,  so  that  there  is  no  "  bulgi- 
ness  "  anywhere ;  other\\-ise  the  telescopic  fit, 
to  be  described  later,  will  be  interfered  with). 
The  molar  band  is  then  fitted  in  the  same  way, 
and  with  slightly  conical  sides,  and  the  exact 
alignment  obtained ;  the  canal  of  the  canine 
is  enlarged  and  notice  taken  that  it  is  in  align- 
ment with  both  bands. 

The  canine  band  is  now  cut  down  ^^ell  below 
the  gum  in  front  {,'.f  inch),  and  standing  out 
from  the  gum  on  the  palatal  aspect  about  yV 
inch  or  more.  This  band  is  converted  into  a 
cap,  and  the  top  should  be  j^^^j  inch  thick.  A 
hole  is  made  through  the  top,  and  the  tube  (in 
length  as  nearly  as  possible  the  length  of  the 
crown  to  be  used)  placed  in  the  canal  and  \vaxed 
in  position,  the  alignment  being  noted.  The 
hole  tlirough  the  top  for  the  tube  should  be 
large,  and  in  waxing  up  the  wax  should  be 
allowed  to  go  well  through,  so  that  \\hen 
soldered  there  will  be  plenty  of  solder  at  the 
junction  underneath — the  reason  for  this  will 
be  seen  later.  The  cap  is  carefully  removed  from 
the  mouth  and  soldered  with  20-carat  solder. 
The  tube  here  referred  to,  and  the  split  pin  to  be 
later  mentioned,  had  better  now  be  described. 

Three  or  four  steel  mandrels  (sizes  52  and  53 
Stubbs'  steel  wire-gauge)  are  obtained,  and  kept 
smooth  and  polished  ;  the  smaller  sizesiare  used 
for  small  teeth  and  narrow  root-canals,  and  the 
larger  for  large  teeth.  A  piece  of  iridio-platinum 
plate  (size  iri>,jT  inch)  in  breadth  the  required 
length  of  the  tube,  is  filed  to  a  knife-edge,  and 
with  half-round  pliers  the  edge  is  turned  slightly 
upwards ;  a  mandrel  is  placed  against  this 
20*  617 


upturned  edge,  the  plate  placed  on  a  bench  anvil 
or  piece  of  fiat  steel,  and  then  by  pressing  with 
a  broad  fine-cut  file  on  the  iridio-platinum  plate, 
and  holding  the  mandrel  tightly  against  it  with 


Fig.  7'j4. 

A.  A.  Iridio-platimim;  B.  Mandrel;   C.   Rladeof  file; 

Arrow — direction  of  movement  of  tile. 

the  left  hand,  the  plate  is  gradually  rolled  round 
the  mandrel  to  form  a  tulje  (see  Fig.  794).  This 
is  soldered  with  pure  gold,  and  the  next-sized 
mandrel  gently  tapped  through  it,  so  as  to 
stretch  it  and  make  the  inside  perfectly  smooth. 
The  surplus  is  then  cut  off,  and  a  piece  of  the 
same  plate  soldered  with  pure  gold  to  one  end 
to  form  the  floor ;  the  surplus  is  cut  off  and  the 
whole  filed  smooth. 

The  split  pin  is  made  from  half-round  wire 
— iridio-platinum  or  platinized  gold  (10% 
platinum) — as  follows  :  a  piece  of  wire  a  little 
longer  than  twice  the  length  of  the  tube  is  bent 
over,  and  the  flat  sides  are  brought  almost  to- 
gether, by  tapping  gently  on  a  bench  anvil,  and 
frequently  annealing  ;  the  ends  are  then  united  by 
a  very  small  piece  of  the  band 
or  pure  gold  ;  the  flat  surfaces 
are  tapped  into  contact  all 
along — if  this  is  done  before 
uniting  the  ends  it  is  difficult 
in  soldering  to  avoid  uniting 
the  surfaces  all  along.  The  pin  is  placed  on  a 
vice  on  the  lathe  and  filed  to  fit  the  tube ;  it  is 
then  left  with  the  ends  closed,  and  is  tightened, 
if  required,  after  the  piece  has  been  worn  a  little, 
by  introducing  a  fine  instrument  between  the 
halves  (see  Fig.  795). 

If  the  pin  is  a  particularly  short  one,  it  is 
better  to  cut  off  the  closed  end,  and  tighten 


Fig.   795. 


618 


Fig.  796. 


by  spreading  the  ends  apart  slightly  with  an 
instrument. 

The  molar  band  is  now  cut  down  to  allow 
room  for  the  top  to  be  put  on,  and  for  the 
outer    cap    and    cusps ;    judgement    will    have 

to  be  exercised  as  to 
how  much  space 
to  leave ;  as  a  rule 
it  will  be  found 
that  the  difficulty 
is  to  have  sufficient 
depth  of  telescopic 
cap  and  at  the  same 
time  plenty  of  room 
for  nicely  shaped 
cusps.  The  requisite 
space  having  been 
obtained,  the  top  is  sweated  or  soldered  on. 
This  molar  cap  (which  is  the  "  inner  cap  ") 
should  now  appear  as  in  Fig.  796. 

The  canine  and  molar  caps  are  then  placed 
in  the  mouth,  and  a  plaster  impression  is  taken  ; 
the  caps  are  waxed  and  a  model  is  cast.  The 
caps  are  removed  from  the  model  by  heating — 
a  piece  of  iron  wire  heated  and  passed  into  the 
tube  of  the  canine  cap  will  remove  it  easily; 
the  wax  is  burnt  out  by  heating  and  replacing 
several  times  on  the  plaster  roots.  The  caps 
are  now  ready  for  the  outer  caps  to  be  made. 

Canine. — The  excess  of  tube  is  stoned  away 
about  level  with  the  cap,  and  the  top  surface  of 
the  cap  is  then  made  perfectly  flat  by  gently 
passing  it  over  the  surface  of  a  fuie-cut  bench- 
file  held  flat  on  the  bench.  The  entrance  to 
the  tube  is  enlarged  somewhat  by  means  of  a 
finishing-burr,  the  bulk  of  solder  that  is  under- 
neath allowing  for  this. 

A  piece  of  the  same  gold  as  is  used  for 
the  band,  ^^§^7  inch  thick,  is  made  perfectly 
flat,  and  cut  distinctly  larger  than  the  surface 
of  the  cap ;  a  hole  is  made  through  it  to 
take  the  split  pin,  and  the  pin  passed  through 
into  the  tube  and  allo\\ed  to  fit  as  tightly  as 

possible.  The  pin 
and  top  are  waxed 
together,  care  being 
taken  that  the  con- 
traction of  the  wax 
does  not  draw  the 
surfaces  of  the  gold 
from  absolute  con- 
tact ;  the  pin  and  top 
are  removed  and 
soldered  with  21- 
carat.  The  piece  is 
then  replaced  on  the 
inner  cap  and  filed  | 
to  a  size  just  larger. 
A  crescent-shaped  piece  of  gold  (r^,{J(7  inch)  is 
cut,  and  fitted  around  the  palatine,  medial,  and 
distal  sides  of  the  inner  cap,  being  brought  round 


the  sides  a  little  more  than  half  way  ;  this  must 
be  carefully  done,  and  must  fit  well  at  B,  B 
(see  Fig.  797) .  A  better  way  than  fitting  by  hand 
is  to  cast  a  piece  to  the  required  shape.  A 
surplus  of  gold  is  left  at  C  (see  Fig.  797). 

The  top  and  crescent-shaped  gold  are  waxed 
together  (care  being  taken  that  the  wax  does 
not  run  through),  removed,  invested,  and 
soldered  with  plenty  of  solder.  One  has  now  a 
removable  half-cap  and  split-pin  abutment  piece. 

Molar. — The  cap  is  removed  from  the  model, 
and  20-carat  solder  is  flowed  around  the  line  of 
junction  of  band  and  top  inside ;  this  reinforces 
the  junction  and  allows  for  rounding  the 
"  corner  "  later,  so  that  the  outer  cap  finds  its 
way  on  better  when  in  the  mouth. 

A  very  thin  film  of  wax  is  flowed  over  the 
inner  surfaces  of  the  cap — to  prevent  union 
« ith  the  fusible  metal  to  be  poured  into  it ; 
the  cap  is  then  placed  in  a  paper  cone,  having 
the  base  of  the  cap  towards  its  narrow  end  (see 
Fig.  798),  and  is  forced  fu-mly  down,  the  cone 
being  held  together  by  means  of  an  elastic  band. 
The  cone  is  placed  in  an  upright  position  (the 
hole  of  a  cotton-reel  is  a  convenient  way 
of  holding  it),  and  fusible  metal  is  poured  in; 
a  metal  cone  is  thus 
formed  with  a  gold  cap 
as  a  ferrule  ;  any  fusible 
metal  over  the  outer  edge 
is  scraped  away,  and  the 
cap  is  rounded  oft'  all 
round  the  junction  of  the 
band  and  top,  the  solder 
previously  flowed  inside 
allowing  for  this  without 
fear  of  makmg  a  hole 
(see  Fig.  799).  It  is  then 
polished  properly,  as  after 
this  no  further  polishing 
can  be  done  except  with 
rouge. 

Measurement  around 
the  middle  of  the  cap  is 
taken  and  another  band 
made  and  gently  tapped 
over  it,  being  frequently 
annealed  so  that  the  one 
collar  is  forced  over  the 
other,  gradually  stretch- 
ing the  gold  and  obtain- 
ing a  perfect  telescopic 
fit. 

The  outer  cap  is  made 
slightly  shorter  than  the 

inner,  i.  e.  so  that  it  will,  when  placed  in 
the  mouth,  reach  to  gum  margin  only,  and  is 
J.!  inch  shorter  all  round  than  the  inner  cap. 
The  inner  cap  and  outer  band  appear  as  in 
Fig.  801 ;  the  outer  cap  is  cut  down  to  the  level 
of  the  inner  at  A,  A  (see  Fig.  802),  and  by 


Fig.  798. 


619 


gradual  burnishing  made  to  fit  closely  there. 
The  tightness  of  the  outer  cap  is  overcome  by 
burnishing  firmly  all  round  until  the  requisite 
degree  of  looseness  is  obtained.  The  outer 
band  is  removed,  and  a  top,  xuhi  ^^^^  thick, 


Fig.  799. 


Fig.  800. 


Fig.  801. 


Fig.  802. 


The  next  step  is  to  put  the  contour  on  the 
molar  cap ;  this  is  done  by  adding  flanges  on  to 
it  by  means  of  solder,  as  follows — 

A  piece  of  gold  is  cut  the  same  size  as 
the  outer  band  and  in  length  about  half  the 

circumference.      It    is    cut 

the  same  shape  as  in  Fig. 

803.     The    lower   edge    of 
Fig.  803.  this  is  bent  a  little,  so  that  it 

only  touches  at  two  points 
when  placed  against  the  band  (see  Fig.  804).  It 
is  now  held  in  this  position  against  the  medial 
surface  of  the  band  in  a  pair  of  pliers,  a  liquid 
flu.x  is  flowed  in,  and  the  gold  held  in  the  Buiisen 
flame  until  the  flux  steadies  the  "  wing  "  piece  of 
gold  in  position  ;  it  is  gently  placed  on  a  soldering 


A.  Fusible  metal;  B.  Band;     A.  Band;  B.  B.   Roimded 
C.  Solder  around  jiinc-  comers  of  band, 

tion  inside. 

sweated  or  soldered  on,  according  to  whether 
the  band  has  been  soldered  or  sweated,  and  one 
has  an  accurately  fitting  telescopic  cap. 

The  edges  of  the  floor  are  now  trimmed  flush 
with  the  sides  of  the  band. 


A  — 


block,  and  a  minute  piece  of  21 -carat  gold  placed 
at  the  point  A  (see  Fig.  805),  and  carefully  fused. 
The  solder  at  this  point  should  really  only  just 
tack  the  band  and  "  wing  "  together,  and  not 


Fig.  804. 


flow  up  between  to  any  appreciable  extent.  A 
similar  piece  is  soldered  on  the  distal  surface  of 
the  band.  This  outer  cap  with  the  attached 
wings  is  now  placed  on  the  inner  cap  (which  is 
stUl  on  the  fusible  metal  die),  and  the  wings  are 
pressed  outwards  to  give  the  required  amount 
of  contour  medially  and  distally.  The  ends  are 
then  bent  in  buccally  and  lingually  to  the 
required  amount,  the  whole  giving  the  natural 
shape  of  the  tooth.  The  outer  cap  is  re- 
moved from  the  inner,  and  the  ends  of  the 
wings  are  held  firmly  against  the  band  with 
pliers,  fluxed  well,  and  held  in  the  flame  until 
the  flux  dries  off ;  this  also  anneals  the  gold, 
and  the  ends  of  the  wings  now  remain  close  to 
the  band  and  do  not  spring  away ;  it  is  then 
placed  on  a  soldering  block  and  further  pieces 
of  21 -carat  solder  are  placed  at  the  juncture 


Fig.  806. 

A,  Telescopic  cap  ;  BB,  Contour  pieces  of  Gold  ; 

C,  Solder. 

lingually  and  buccally  (see  Fig.  806).  This  solder 
is  flowed  well  round  by  fusing  and  drawing  the 
flame  round,  starting  at  the  lingual  or  buccal 
aspect  as  the  case  may  be,  but  never  putting 
any  more  solder  medially  or  distally,  as  there  is 
so  little  room  to  solder  that  it  may  easUy 
flow  inside  the  band  and  so  spoil  the  fit. 
Plenty  of  solder  is  used  to  allow  for  filing  up  and 
finishing. 

The  surplus  contour  or  wing  is  cut  off,  and 
the  whole  made  flush  with  the  floor  of  the  cap ; 
a  cusp  of  gold  is  made  as  previously  de- 
scribed for  a  fixed  bridge,  fUed  flat  accurately 
to  flt  the  cap,  wired  to  it,  and  soldered  with  20- 
carat  solder.  The  soldering  is  best  accomplished 
by  placing  the  abutment  piece  on  the  soldering 
block  and  using  the  blowpipe.  The  casting 
process  can  be  used  advantageously  here,  as 
the  contour  can  be  cast  directly  on  to  the  outer 


620 


cap ;  or  it  can  be  cast  separately  and  soldered 
on,  and  the  cusps  then  soldered  as  previously 
described ;  or  again,  contour  and  cusps  can  be 
cast  directly  in  one  piece  on  to  the  cap.  It  is 
best  to  reinforce  the  junction  of  the  cast  part 
\nth  the  cap  with  a  little  solder,  in  case  the 
union  is  not  perfect,  as  is  sometimes  the  case  ;  a 
better  finish  can  also  be  thereby  obtained. 

The  further  steps  in  the  bridge  are  the  same 
as  for  a  fixed  bridge,  except  of  course  that  when 
waxed  up  for  soldering  the  imier  cap  must  be 
carefully  removed  before  investing.  This  is 
a  delicate  operation  as  it  is  easy  to  distort  the 
wax  unless  great  care  is  used,  but  by  employing 
a  hard  and  brittle  wax  that  will  break  and  not 
stretch,  and  by  leaving  enough  of  the  imier  cap 
showing  to  enable  one  to  get  a  firm  hold  of  it, 
it  can  usually  be  done  without  nuich  trouble. 


Fig.  807. 


Fig.  8U8. 

Figs.  807  and  808  show  an  upper  removable 
bridge,  with  a  telescopic  premolar  abutment- 
piece,  and  a  split  pin  in  the  molar  (it  being 
supposed  that  the  molar  was  too  shallow  to 
allow  of  a  telescopic  abutment-piece  being  used 
satisfactorily). 

Drill  Guide. — A  very  u.seful  form  of  "drill 
guide  "  is  that  devised  by  P.  S.  Campkin  (2) ;  it  is 
used  for  obtaining  proper  parallelism  of  the  canals 
in  removable  cases,  where  each  abutment  piece 
is  to  consist  of  a  split  pin  and  half-cap.    Campkin 


describes  this  guide  and  its  method  of  employ- 
ment as  follows — 

"  It  consists  of  movable  bars  united  by  a 
hinge  joint  controlled  by  a  nut,  with  two  small 
tubes  at  each  extremity,  the  inside  diameter 
of  which  corresponds  to  pin-size,  and  is  used 
as  a  '  drill  guide  '  in  the  following  mamier  : 
Each  canal  is  opened  the  entire  length,  and 
after  suitable  treatment,  each  apex  is  perma- 
nently plugged  with  gutta-percha  or  other 
form  of  filling ;  this  prevents  any  foreign 
material  being  pushed  through  the  apex  in 
subsequent  treatment.  The  available  depth 
of  each  canal  is  noted,  and  a  small  twist-drill 
used  as  a  commencement  of  the  enlargement. 
A  second  twist  drill  is  now  used,  larger  than 
the  first,  but  smaller  than  pin-size.  The  canal 
of  one  root  is  now  enlarged  to  pin-size  by  twist- 
drill  No.  3.  The  pin  of  the  guide  is  passed 
through  the  tube  at  the  extremity  of  the  other 
bar,  and  into  the  canal  of  the  root.  The  tube 
at  the  extremity  of  the  other  bar  is  adjusted 
over  the  entrance  of  the  root-canal  to  be  reamed, 
and  the  position  fixed  by  tightening  the  nut 
in  the  centre ;  the  pin-size  twist-drill  is  passed 
through  this  and  allowed  very  gradually  to 
enlarge  the  canal  to  its  available  depth,  any 
pressure  or  undue  force  being  avoided." 


ABUTMENTS   FOR   REMOVABLE   BRIDGES 

Telescope  and  Split-Pin  Combination. — In  the 
foregoing  description  of  a  typical  removable 
bridge,  the  ordinary  haK-cap  and  split  pin, 
and  the  telescope-cap  abutment  pieces,  have 
been  described ;  mention  will  now  be  made  of 
other  forms  of  abutment  pieces  that  are  used  in 
removable  work. 

The  combination  of  the  telescope-cap  and 
split  pin  in  cases  where  the  teeth  are  short  is 
very  useful,  and  is  made  in  the  following 
manner  :  The  imier  cap  is  made  in  the  ordinary 
way ;  a  hole  is  made  through  the  top,  the  cap 
placed  on  the  root,  and  a  tube  passed  through 
the  hole  into  the  pulp-chamber  or  a  canal  of  the 
tooth  and  waxed  firmly  in  place,  having  the 
tube  parallel  with  the  sides  of  the  cap ;  this  is 
removed  and  soldered,  and  then  the  tube  is 
cut  flush  with  the  top.  The  outer  cap  is  now 
constructed,  the  exact  position  of  the  tube  being 
located  by  tapping  with  a  piece  of  wood  over 
the  entrance  to  the  tube ;  a  hole  is  cut  for 
the  split  pin,  which  is  passed  through  the  outer 
cap  into  the  tube,  fitting  the  tube  loosely,  but 
the  outer  cap  tightly ;  it  is  waxed  in  place, 
the  outer  cap  is  removed  without  disturbing  the 
wax,  and  the  two  are  soldered  together.  The 
piece  is  then  finished  as  before  described. 

Inlays. — Another  form  is  the  Inlay  Attach- 
ment, which  is  specially  useful  in  molars — 


621 


Fig.  S09. 


The  tooth  is  devitalized  and  treated,  and  the 
pulp-chamber  filled  flush  with  gutta-jjercha. 
A  non-retentive  cavity  is  cut  in  the  crown 
surface,  and  brought  through  to  the  medial 
or  distal  surface,  as  the  position  of  the  bridge 
may  require.  In  this  cavity  is  put  burnished 
platinum  foil  as  for  an  ordinary  inlay ;  a 
platinum  tube  is  passed  through  the  floor  of 
the  matrix  and  through  the  gutta-percha  to  the 
floor  of  the  pulp-chamber,  care  being  taken  that 
the  alignment  with  the  other  abutment  f)iece  is 
correct ;  wax  is  flowed  into  the  matrix,  and  the 
edge  carefully  adapted,  and  the  whole  removed, 
invested,  and  filled  with  hard  band  gold.  A 
groove  is  then  cut  in  the  inlay 
from  the  edge  to  the  tube 
sufficiently  deep  to  take  a  split 
pin,  which  has  been  made  to 
fit  the  tube  (see  Fig.  809).  A 
split  pin  is  then  adjusted,  the 
inlay  placed  in  the  mouth  and 
the  impression  taken. 

A  somewhat  easier  way  is  to  "  cast  "the  inlay 
in  22-earat  gold,  having  the  tube  in  position 
in  the  wax,  and  partially  to  form  the  groove 
for  the  pin  in  the  wax,  making  it  quite  smooth 
and  even  afterwards  by  means  of  stones. 

"  Key  and  Shoe." — A  form  of  attachment 
known  as  the  "  Key  and  Shoe  "  is  described  by 

Peeso    (6,   p.    799)   as 

follows 

"  The   key  is  made 

of  iridio-j)latinum,  and 

filed  smooth  to   form 

a  dovetail,  as  in  Figs. 

810,  811.     A  strip  of 

the  same  metal.  No.  32 

American  gauge,  is  bent  to  fit  the  side  of  the  key 

perfectly,  and  filed  off  even  with  the  face  or 

broad  side  of  the  key,  and  a  floor  of  the  same 

^^ -,  V  I    metal  fitted  to  it  and 

\ '  \\      //    soldered    with  a   little 

Fig.  812.  Fig.  813.    P"re     gold     (see    Figs. 

812,  813). 

"  In  using  this  form  of  abutment-piece  the 

side  of  the  crown  to  which  the  key  is  to  be 

attached  should  be  .straight,  from  the  gum  line 

to  the  tojj  of  the  cusp,  and  should  be  reinforced 

_      with  a    piece   of   coin   gold,   No.   28 

i\   American  gauge,  soldered  across  the 
]   whole  face   of    the   crown    (see    Fig. 
/    S14). 
,  "  The    key   is   then  put  in  place, 

and  a  hole  drilled  through  it  and  the 
Fio.  814.  side  of  the  band,  and  it  is  fastened 
with  a  small  platinum  rivet,  such 
as  a  toothpin,  the  under  surface  of  the  key 
having  first  been  covered  with  pure  gold,  as 
the  union  between  iridio-platuium  and  solder 
is  not  strong.  It  is  then  soldered  to  the  cap, 
very  little  solder  being  used  (see  Figs.  815,  81b). 


P'iG.  810. 


SO 


Fig.  811. 


"  The  shoe  is  then  slipped  over  the  key,  and 
a  thin  piece  of  platinum  cut  out  to  shp  down 
over  the  key  next  to  the  crown,  and  this  is 


A 


Fig.  815. 


o 


Fig.  81(3. 


LnJ 


burnished  closely  to  it  (see  Fig.  817).  It  is 
then  waxed  to  the  shoe,  removed,  invested, 
and  covered  %vith  pure  gold,  after  which  it  is 
trimmed  to  its  proper  dimensions, 
and  rejilaced  on  the  crown,  the 
facings  are  ground  in,  and  the 
bridge  is  constructed. 

"  If  a  saddle  is  to  be  used,  it  is 
first  waxed  carefully  to  the  shoe, 
removed,  and  soldered,  after  which 
it  is  replaced  on  the  model,  and 
the  bridge  constructed  as  before 
described." 

Split  Pin  and  Tube. — For  a  case 
where  the  two  roots  that  are  to 
serve  as  abutments  are  out  of 
the  parallel  to  such  an  extent  that  it  is  impossible 
to  insert  tubes  sufficiently  deeply  and  yet  have 
them  parallel,  Peeso  (6,  p.  802)  describes  as 
follows  an  attachment  of  a  split  pin  and  tube, 
but  the  tube  is  embedded  in  the  bridge  and 
the  pin  is  in  the  root  and  attached  to  the  inner 
cap — 

"  The  roots  are  prepared  in  the  same  way 
as  when  they  stand  in  a  normal  position,  \vith 
this  exception — the  approximal  angles  are  cut 


Fig 


Fig,  818. 

away,  in  order  that  the  bands  may  be  adjusted 
with  their  sides  nearly  parallel  to  each  other. 
The  bands  are  then  fitted,  the  roots  cut  down, 
and  the  canals  enlarged  to  receive  a  strong 
pin,  and  a  plaster  impression  is  taken  with  the 
bands  and  pins  in  position,  as  in  Fig.  818. 

"  A  cast  is  then  made,  the  bands  are  cut  flush 
with  the  top  of  the  stump,  and  a  flow  of  28 
American  gauge  coin  gold  is  sweated  or  soldered 
to  them.  An  opening  is  then  made  through 
the  floor  to  fit  the  pins  tightly,  and  the  pins 
are  bent  first  beneath  the  floor,  so  that  when 


622 


they  pass  through  they  will  be  parallel  with 
each  other  or  nearly  so  (see  Fig.  819).  They 
are  then  waxed  together,  invested,  and  soldered 
from  the  under  side. 


Fig.  819. 

' '  In  niakuig  the  outer  cap,  the  floor  of  y^^  inch 
coin  gold  is  drilled  so  as  to  fit  the  pin  easily  but 
not  loosely.  It  is  then  cut  flush  with  the  sides 
of  the  inner  cap,  and  tlie  half-band  made  and 
soldered  to  it,  after  which  it  is  replaced  on  the 
iimer  cap.  The  tube  is  next  placed  over  the  pin, 
and  is  made  to  sit  down  closely  on  the  floor  all 
around,  and  is  waxed  to  it  with  hard  wax ;  it 
is  then  removed,  a  little  investing  material 
carried  into  the  tube,  and  a  small  iron  wire 
iiLserted,  and  allowed  to  extend  about  one 
quarter  of  an  inch  below  the  floor  (see  Fig.  820). 
This    will    hold   the   tube    in    position,   and   is 


Fig.  820. 


Fig.  821. 


embedded  in  the  investment,  the  tube  being 
soldered  to  the  floor  with  22-carat  solder  (see  Fig. 
821).  The  facing  is  then  ground  to  the  floor  of 
this  cap,  and  when  the  bridge  is  invested  for 
soldering,  a  small  iron  wire  is  inserted  in  the 
investment  to  prevent  the  tube  from  shifting, 
the  same  as  when  attaching  it  to  the  floor." 

In  cases  where  one  end  of  the  bridge  is 
supported  by  means  of  a  spur  resting  on  a 
filling  in  the  abutment,  iridio-platinum  wire  is 
u.sed,  of  a  size  varying  from  1  to  4  gauge  (Ash), 
according  to  the  size  of  the  bridge  it  has  to 
support.  It  is  best  to  let  the  spur  rest  in  a  gold 
fining  or  gold  iiJay,  and,  as  a  rule,  it  wfll  be 
found  that  the  inlay  answers  the  purpose  best ; 
it  is  absolutely  solid,  and  the  requisite  grooving 
can  be  made  more  easily  in  a  smaller  filling  than 
could  be  managed  if  the  gold  were  inserted  in 
the  ordinary  way,  because  of  the  danger  of 
weakening  the  filling  by  cutting  the  countersunk 


part.  The  inlay  can  always  be  perfectly  made, 
as  there  is  no  contiguous  tooth. 

Ready-made  Attachments. — Many  ingenious 
devices  for  attachment  have  been  described 
from  time  to  time  by  different  writers,  but 
most  of  them  have  the  great  fault  of  being 
unnecessarily  complicated  and  difficult  to  make 
properly  and  adapt,  and  in  most  cases  when 
it  is  advised  that  they  can  be  used,  other 
and  more  simple  methods  can  be  employed. 

In  discussing  the.se  methods  Goslee  (4,  pp.  492 
et  seq.)  ably  sums  up  their  advantages  and  dis- 
advantages, and  speaking  more  particularly  of 
devices  made  by  the  manufacturers  he  says — 

"  These  attachments  vary  considerably  in 
design,  but  are  usually  composed  of  two  parts 
that  telescope  into  or  over  one  another, 
of  which  one  is  to  be  securely  attached  to 
the  supporting  tooth  and  the  other  to  the 
removable  fixture. 

Advantages. — The  advantages  that  are  to 
be  derived  from  the  use  of  such  forms  of 
attachment  lie  in  the  facility  with  which 
anchorage  to  the  supporting  teeth  may  be 
obtained  ;  in  the  more  or  less  secure  means  of 
fixation  that  they  afford ;  in  the  fact  that  the 
parts  are  usuaUy  machine-made  and  therefore 
accurately  adjusted  in  their  relation  to  one 
another,  and  that  they  may  be  obtained  ready 
for  immediate  use  directly  from  the  manufac- 
turer or  dealer,  thus  saving  the  expenditure 
of  time  and  energy  in  devising  a  means  of 
otherwise  retaining  such  pieces. 

Disadvantages.  — •  Notwithstanding  the  nu- 
merous possible  advantages,  however,  such 
attachments  as  are  even  yet  used  and  recom- 
mended are  neither  universally  applicable, 
nor,  as  a  rule,  free  from  objectionable  features. 
These  are  usually,  firstly,  inherent  weakness, 
\\  hich  results  in  their  soon  becoming  broken ; 
secondly,  a  demand  for  such  precise  and  ac- 
curate parallelism  when  two  are  to  be  on  a 
single  piece  as  to  require  the  use  of  a  '  parallel- 
ing '  instrument,  and  the  exercise  of  a  greater 
degree  of  skill  than  is  ordinarily  possessed 
by  the  average  dentist,  thus  making  their 
use  too  intricate  and  uncertain;  thirdly,  the 
extent  of  space  occupied  by  the  attachment 
itself,  and  obtained  at  the  expense  of  the 
adjustment  of  the  teeth  to  be  supported  by 
the  fixture  ;  fourthly,  the  possible  subsequent 
loosening  of  the  parts  in  their  inter-relation, 
as  a  result  of  continued  friction  and  stress, 
which  may  soon  render  them  useless;  fifthly, 
a  lack  of  provision  or  opportunity  for  easily 
overcoming  this,  or  for  tightening  the  adjust- 
ment ;  and  sixthly,  the  leverage  imposed  upon 
the  supporting  teeth,  which  may  be  so  severe 
as  to  result  in  their  subsequent  loosening, 
or  ultimate  loss. 

Indications. — Whenever      opportunity      for 


623 


minimizing  these  objectionable  features  seems 
to  be  present,  and  whenever  suitable  anchorage 
teeth  remain  in  the  mouth,  and  the  form  of 
attachment  best  adapted  to  the  case  is  judi- 
ciously selected  and  properly  and  skilfully 
adjusted,  such  attacliment  may  be  success- 
fully employed." 

SADDLE   BRIDGES 

In  a  bridge  in  the  maxilla  from  canine  to 
canine  where  the  arch  is  of  the  V-shaped  variety, 
a  very  useful  form  of  bridge  can  be  constructed 
by  making  a  saddle  of  heavy  gold  and  soldering 
it  to  the  half-caps  on  the  two  canines,  having 
the  saddle  fitting  tightly  on  the  ridge.  On  the 
saddle  may  be  mounted  tube-teeth  in  the 
ordinary  way  ;  or  flat  teeth  or  gum  sections  may 
be  fitted  on  the  gum  and  soldered  to  tlie  saddle, 
in  which  case  the  piece  must  be  built  up  very 
solidly  with  solder  to  give  sufficient  strength,  the 
natural  shape  of  the  teeth  behind  being  obtained 
by  means  of  stones  on  the  dental  engine. 

The  saddle  in  different  forms  may  be  made 
use  of  in  the  molar  and  premolar  region  also, 
a  useful  form  of  bridge  being  made  by  vul- 
canizing teeth  on  to  a  gold  saddle  attached  to 
the  removable  abutments. 

A  point  to  note  in  connection  with  taking  the 
models  for  all  these  forms  of  saddles  is  as  follows  : 
After  the  first  model  and  the  removable  abut- 
ment pieces  have  been  made,  another  model 
is  taken  in  modelling  comjjosition  used  fairly 
hard  (with  the  abutment  pieces  on  the  roots). 
This  procures  a  model  of  the  alveolar  ridge  in 
which  the  soft  tissues  have  been  forced  well 
aw  ay  by  the  composition  ;  the  outline  of  the 
required  plate  is  marked,  and  a  little  wax 
placed  along  it  to  ease  the  edges  of  the  jjlate. 
The  alveolar  ridge  is  also  waxed  slightly,  and 
then  dies  and  counter-dies  are  made  in  the 
ordinary  way,  and  the  plate  is  struck ;  this, 
when  placed  in  the  mouth  and  held  firmly 
there,  will  be  seen  to  have  no  "  rock". 

In  the  form  of  saddle  to  be  next  described — 
that  of  two  premolars  on  the  same  side  being 
employed  as  abutments  and  attached  to  an 
extension  saddle  supplying  the  lost  molars — • 
this  accurate  fitting  of  the  saddle  on  the  alve- 
olar ridge  is  highly  important ;  here,  if  not 
correctly  made,  the  saddle  will  "  settle  ",  carry- 
ing posteriorly  with  it  the 
two  premolars,  bringing  a 
great  strain   on  them,   and 

„       „,-  thereby  causing  their  earlv 

Fig.  822.  i  • 

loss. 

Peeso's   method   of   obtaining   this   accurate 

adjustment  is  to  strike  up  the  saddle  in  soft 

platinum,  about  yJ;-,,y  inch   thick,   having   the 

edges   shghtly  turned  up  (see  Fig.  822) ;    gold 

of  the  carat  and  constitution  of  coin  gold  is 


Fig.  823. 


flowed  over  the  surface  of  the  plate  so  as  to  fill 
the  edges  flush  with  the  plate  (see  Fig.  823),  and 
then  it  is  tried  in  the  mouth,  the  amount  of  rock 
noted,  and  the  saddle  adjusted 
by  pressing  the  sides  together 
with  the  fingers.  The  inner 
caps  having  been  made,  they 
j  are  placed  in  the  mouth  to- 
'  gather  with  the  saddle ;  the 
saddle  is  held  in  place  by  the  tip  of  the  finger, 
and  a  plaster  impression  taken,  the  finger  being 
kept  on  the  saddle  until  the  plaster  has  set.  This 
is  cast,  the  outer  telescope -caps  are  made,  waxed 
together  and  also  to  the  saddle,  and  the  whole  is 
taken  off  the  model ;  the  inner  caps  are  then  re- 
moved from  the  outer,  the  piece  is  invested,  and 
the  two  caps  and  saddle  are  joined  by  20  or  21  carat 
solder ;  the  inner  caps  are  then  replaced  in  the 
outer,  the  whole  is  placed  in  the  mouth,  and 
another  model  with  articulation  taken  (which 
need  not  now  be  in  plaster). 

If  this  method  is  not  followed,  and  if  the 
abutment  pieces  are  soldered  to  a  saddle  that 
has  been  made  on  the  original  model  and  has 
not  been  adjusted  in  the  mouth  (as  one  would 
do  in  the  case  of  a  plate  and  bands),  it  will 
be  seen  that  the  saddle  does  not  sit  firmly  on 
the  alveolar  process  when  the  piece  is  finally 
finished  and  placed  in  the  mouth,  and  conse- 
quently the  strain  of  mastication  is  all  brought 
to  Ijcar  on  the  abutments,  and  the  advantage 
of  the  alveolar  process  taking  part  of  the  strain 
is  thereby  lost,  although  this  support  from  the 
alveolar  process  should  be  part  of  the  advantage 
of  the  saddle  bridge  ;  a  bridge,  of  course,  cannot 
settle  to  the  mouth  as  a  plate  would. 

The  subsequent  steps  for  finishing  the  piece 
may  be  by  means  of  tube-teeth  (in  which  case 
it  is  advisable  to  re- 
inforce the  saddle 
further  by  strikmg 
up  a  piece  of  plate 
gold  to  fit  the  upper  a  __--' 
surface  of  the  saddle, 
and  then  soldering 
it  as  one  would  an 
ordinary  bar  lower), 
or  by  a  method  Peeso 
employs,  which  will 
be  now  described, 
and  which  makes  a 
very  beautiful  result, 
although  the  amount 
of  gold  used  makes 
it  a  very  expensive 
method. 

Peeso    (6,   p.   806)   sa^'s — 

■'  In  constructing  a  saddle  bridge  it  is  better 
that  the  facings  should  not  be  ground  to  fit 
the  saddle  exactly,  but  should  stand  away  from 
it  for  a  little  distance  (see  Fig.  824),  the  object  of 


Fig.  824. 


624 


which  \vill  be  seen  later.  The  tips  of  the  facings 
should  be  high  enough  to  touch  the  Hngual 
side  of  the  buccal  cusps  of  the  upper  molars, 
as  in  Fig.  824,  A. 

"  After  the  facings  have  been  ground  they 
are  held  in  place  with  wax,  and  a  wall  of  plaster 
is  built  up  on  the  buccal  side  so  as  to  retam  them 
m  position  after  the  wax  has  been  removed  (see 
Fig.  825).     The  facings  are  then  removed,  and 


Fig.  825. 

the  occlusal  ends  ground  off  at  an  angle  of  about 
45°  with  the  backs  or  lingual  side,  as  in  Fig.  825, 
A,  leavmg  them  so  that  they  will  clear  the 
occludmg  teeth  by  about  ^,\,  of  an  inch. 

"  The  facings  arelthen  backed  with  thin 
platinum,  the  backings  touching  each  other 
and  extending  from  the  begimiing  of  the  level 
at  the  occlusal  end  to  the  saddle,  which  they 


Fig.  82(). 


Fig.  827 


should  touch  closely  all  along  (see  Fig.  826). 
The  facings  are  then  waxed  firmly  to  the  saddle 
with  hard  adhesive  wax,  the  wax  being  high 
enough  to  support  and  hold  the  cusps  (see 
Fig.  827). 

"  A  solid  cusp  must  be  used  (of  coin  gold), 
the  buccal  side  ground  or  filed  to  fit  the  bevel 
of  the  facing,  and  waxed  in  place. 

"  The    buccal    and    lingual    sides    are    next 


covered  with  wax,  the  pink  paraffin  wax  being 
preferable,  as  it  is  not  sticky  and  carves  nicely. 
Both  sides  are  then  carved  to  represent  the 
natural  gums.  This  should  be  done  very 
carefully  and  the  wax  made  perfectly  smooth 
in  order  to  secure  a  clean  die,  so  that  when  the 
plates  are  struck  up  they  will  require  no  finishing 
other  than  with  pumice  and  rouge.  On  the 
buccal  side  it  should  be  carried  above  the  lower 


Fig.  829. 


Fig.  828. 

edge  of  the  facings,  and  well  up  between  them, 
as  in  Fig.  828 ;  the  carving  on  the  lingual  side 
should  correspond  in  depth  and  breadth  with  the 
facings  on  the  buccal  side. 

"  An  impression  is  then  taken  of  each  side 
separately,  the  plaster  being  carried  well  above 
the  gum  line  and 
over  the  heel  on  the 
buccal  side,  and  on 
the  lingual  side  well 
above  the  cusps  and 
below  the  saddle, 
and  far  enough  over 
the  heel  to  meet  the 
impression  from  the 
buccal  side  (see  Fig. 
829). 

"  The  impression 
should  be  deep 
enough  to  serve  as 
a  model  from  which 
to  get  good  strong  dies.  The  dies  and  counter- 
dies  are  made,  the  buccal  plate  is  strack  up  from 
coin  gold  y  r,  Jf  ,7  inch,  and  festooned  carefully  to  fit 
around  the  facings.  The  lingual  plate  is  struck 
up  from  coin  gold  t-J4jj  inch  and  fitted  care- 
fully, the  f)art  going  over 
the  heel  being  brought  in 
contact  with  that  from  the 
buccal  side. 

''  After  they  have  been 
cleansed  in  acid,  the  buccal 
plate  is  placed  in  position 
and  held  with  small  iron-wire 
clamps,  as  in  Fig.  830.  The 
saddle  is  then  held  over  a 
small  flame  for  a  moment 
to  loosen  the  wax  from  the  plate,  and  the 
teeth  and  ^^•ax  are  removed  and  laid  carefully 
aside.  The  saddle  is  then  invested,  lingual  side 
down,  only  just  enough  of  the  investment  being 
used  to  keeji  it  from  springing  (see  Fig.  831)'. 

"  The   investment  is   thoroughly   dried   out, 


Fig.  830. 


625 


the  piece  well  fluxed,  and  some  pieces  of  18-carat 
solder  dropped  in  between  the  saddle  and  plate. 
It  is  then  well  heated  up,  and  when  it  has 
reached  a  red  heat  the 
lilowpipe  flame  is  thrown 
on  the  under-side  of  the 
saddle  next  to  the  invest- 
ment, and  the  solder  drawn 
through  all  round.  ^Vhen 
cool,  it  is  cleansed  in  acid 
and  the  saddle  warmed 
slightly,  and  the  teeth  are 
pressed  back  into  place 
until  the  fitting  of  the 
lingual  plate  shows  that 
they  are  in  their  correct 
position. 

The  bridge  is  now  ready  for  the  final  solder- 
ing. The  piece  is  invested,  buccal  side  down, 
the  investment  on  the  occlusal  side  covering 
about  two-thirds  of  the  cusps  and  the  saddle,  to 
within  about  ^  inch  of  the  lingual  edge  (see  Fig. 
832,  Aand  B).  After  the  investment  has  hardened 
it  is  warmed  up  a  little,  and  the  wax  lifted  out. 


Fig.  832. 

It  is  then  thoroughly  heated  up  to  a  light-red 
heat,  fluxed  and  soldered  between  the  cusps 
\vith  20-carat  solder,  the  backings  being  united 
and  connected  with  the  saddle  with  the  same 
solder,  of  which  enough  must  be  used  to  give 
sufficient  strength  and  support  the  bridge  (see 
Fig.  833).     Some  18-carat  solder  is  then  melted 


Fig.  833. 

over  the  lingual  side  of  the  saddle  and  cusps  at 
A  and  B,  Fig.  833,  and  the  lingual  plate  carefully 
put  in  place,  having  been  previously  fluxed  on 
the  inner  side.  The  whole  investment  is  then 
thoroughly  heated  to  a  bright-red  heat,  and  the 
flame  of  the  blowpipe  passed  along  the  under- 
side of  the  saddle  and  the  exposed  portion  of 


the  cusps  (see  Fig.  834),  until  the  .solder  has  been 
drawn  through  and  has  united  the  lingual  jslate 
all  round.  The  greatest  care  must  be  exercised 
in  putting  on  this  plate  as  it  has  to  be  heated 
so  very  hot  that  it  is  easily  burned. 

"  After  it  has  cooled  it  is  removed  from  the 
investment,  boiled  in  dilute  acid,  washed,  and 
then  dipped  in  alcohol  and  thoroughly  dried. 
The  points  of  the  buccal  plate  that  have  been 


Fig.  834. 

carried  up  between  the  facings  are  now  bent 
outwards,  and  the  space  between  the  plate 
and  the  saddle  and  under  the  facmgs  is  filled 
with  oxy -phosphate  of  zinc.  While  the  cement 
is  yet  soft,  the  points  of  the  plate  are  pressed 
back  again  between  the  facings.  After  it  has 
hardened,  the  cement  is  cleaned  out  from 
between  the  teeth,  and  plastic  gold  is  packed 
in  and  over  the  points  of  the  plate. 

"The  bridsje  is  then  readv  to  articulate  and 
finish." 

PRESSURE-CASTING 

A  description  had  better  be  given  here  of  the 
modifications  of  bridge -work  brought  about 
by  the  advent  of  pressure-casting ;  this  method 
of  work  is  undoubtedly  revolutionizing  all 
previous  methods,  and  by  its  means  many 
beautiful  results  may  be  obtauied — results 
which  are  more  aesthetic,  stronger,  easier  of 
repair,  and  easier  of  application,  in  difierent 
cases ;  the  problem  of  the  change  of  colour  of 
the  tooth,  both  when  making  the  bridge  and  by 
the  lapse  of  time,  is  much  simplified,  as  methods 
may  be  adopted  that  admit  of  the  facing  not 
going  through  any  "  firing  ". 

The  description  of  the  making  of  abutment 
pieces  from  the  point  of  view  of  casting  has 
been  referred  to,  and  w  ill  not  be  given  in  further 
detail,  as  that  is  dealt  with  under  "  Artificial 
Crowns  "  (Chapter  XXXV,  pp.  567-70). 

In  anterior  teeth,  where  a  half-cap  and  pin 
are  used  for  fixed  bridge-work,  this  can  be 
made  all  in  one  piece  by  castuig,  and  a  very 
accurate  adaptation  of  the  half-cap  can  be 
obtained;  the  facing  can  also  be  made  re- 
movable, that  is  the  gold  can  be  cast  on  to 
the  backing  of  some  form  of  removable  facing, 
or  an  ordinary  facing  can  be  used  and  removed 
from  the  wax  before  casting,  bemg  afterwards 


626 


cemented  into  place  ;  by  this  means,  too,  supple- 
mentary facings  can  be  easily  adjusted  for  use 
in  case  of  fracture. 

With  reference  to  the  "  body  "  of  a  bridge, 
the  employer  of  the  casting  process  will  see 
many    ways    of    using   it.      It    is  particularly  1 
useful   in  "forming    "  saddles  "   combined   with 
"  tube  "  or  "  dowel  "  teeth,  the  perfect  adapta- 
tion  of  the  teeth  to  the  saddle  being  easily 
obtained,  and  the  strengthening  of  the  saddle 
at  the  requisite  pomts  much  more  easily  made. 
The  aesthetic  effect  also  can  be  enhanced  by 
employing    "  tubes  "  or    "  dowels  ",   combined 
with  equal,  and  in  many  cases  greater,  strength. 
Large  gold  uilays  may  be  used  as  abutments 
with  great  advantage.     To  get  the  best  results, 
however,  the  inlay  must  be  cast  separately  from 
the  body  of  the  bridge,  and  united  to  it  by 
solder;    otherwise,  owing  to  the  slu-inkage  of 
the  gold  during  casting,  the  inlay  will  not  go 
accurately  into  place.     If  a  minimum  of  high- 
carat  solder  is  used  to  join  the  inlay  and  bridge 
body,   an   excellent    result   is    obtained.     This 
method  api^lies  more  particularly  to  cases  where 
the  inlay  is  of  a  large  size  ;  with  a  small  inlay  an 
accurate  result  is  extremely  difficult,  in  addition 
to  its  not  being  strong  enough.     But  even  where 
every  care  is  taken,  and  with  the  best  possible 
manipulation  and  workmanship,  the  soldering 
of   a  bridge  to  an  inlay  must    mean  that   the 
inlay  is  ever  so  slightly  altered  in  its  relationship 
to  the  bridge,  and  hence  when  placed  in  the 
mouth  the  inlay  is  certain  not  to  go  absolutely 
accurately    into    place.     However    slight    this 
inaccuracy   is,    it    is    particularly    undesu-able, 
inasmuch  as  it  is  situated  at  a  most  vulnerable 
part  of  the  bridge;    hence  the  "  bar  and  slot  " 
previously  mentioned  is  to  be  preferred  in  both 
fixed  and  removable  work,   because  the   very 
slight    alteration  of    relationships  of    the    bar 
and   slot    is  immaterial  to    the  success  of    the 
piece.     For  the  inlay  itself  to  be  at  fault  is 
to  invite  disaster. 

Then  again,  a  great  advantage  of  a  cast  inlay 
is  that  very  often  the  abutment  tooth  need  not 
be  devitalized,  if  sufficient  strength  of  "seat  " 
for  the  inlay  can  be  obtained ;  this  strength 
requires  great  nicety  of  judgement,  and  in  doubt- 
ful cases  it  is  better  to  devitalize  and  secure  with 
a  pin  in  the  pulp-chamber ;  some  writers  advise 
drilling  holes  in  the  dentine  of  a  live  tooth  and 
placing  pins  therein  attached  to  the  inlay,  but 
this  is  of  doubtful  utility,  as  it  is  so  often  in- 
applicable on  account  of  danger  to  the  pulp  and 
the  weakening  of  the  tooth. 

The  different  methods  of  inlay  formation  are 
described  in  Chapter  XXV,  and  the  technique 
will  not  here  be  gone  into.  Some  points,  how- 
ever, must  be  remembered  particularly  :  very 
great  strength  of  "  seat  "  is  necessary  for  use 
as  an  abutment  piece  ;  extension  for  prevention. 


when  possible,  must  be  carefuUy  carried  out ; 
and,  as  pointed  out  before,  whenever  possible 
the  inlay  abutment  and  bridge  should  not  be 
united  together. 

CEMENTING  OF  BRIDGES 

In  cementing  bridges  it  is  advisable  to  use  a 
hydraulic  cement  and  one  that  does  not  set 
too   quickly. 

The  inner  surfaces  of  the  caps  are  washed 
thoroughly,  swabbed  out  with  chloroform  and 
then  slightly  roughened  with  the  point  of  a 
sharp  instrument ;  the  abutments  are  made 
perfectly  dry  mth  chloroform  or  absolute 
alcohol.  The  oozmg  of  the  gum  may  be 
controlled  by  means  of  25%  pyrozone  on  a 
wisp  of  absorbent  cotton-wool. 

The  cement  is  mixed  and  placed  in  the  abut- 
ment pieces  first,  then  it  is  applied  to  the  root 
and  canals  and  the  bridge  quickly  forced  mto 
place. 

It  is  advisable  always  to  see  that  the  bridge 
goes  properly  home  before  the  cement  is  mixed ; 
edges  and  corners  have  very  often  to  be  rounded 
off  to  allow  of  this ;  in  cases  where  the  bridge 
fits  exceedingly  tightly  it  may  be  left  in  the 
mouth  uncemented  for  twenty-four  hours,  when 
the  taking  on  and  off  wiU  be  much  easier. 

In  removable  bridges  the  imier  cap  is  placed 
in  the  outer,  and  the  junction  between  them 

1  must  be  protected  with  a  film  of  wax,  as  other- 
wise the  cement  squeezes  in  and  converts  the 
movable  bridge  into  a  fixed  one,  at  any  rate 
for  a  considerable  time,  an  accident  that  is 
extremely  disconcerting.  The  film  of  wax 
must  be  only  "  plastered "  on  lightly,  not 
heated  and  run  on,  for  if  made  too  hot  it  also 
makes  it  very  difficult  to  remove  the  bridge 
when  the  cement  has  hardened. 

j       No  attempt  should   be   made  to  take  off  a 

!  removable  bridge  for  several  hours  after  cement- 
ing it. 

j  REPAIRING    OF    BRIDGES 

One  of  the  greatest  difficulties  in  bridge-work 
of  the  fixed  variety  is  properly  to  repair  a  broken 
bridge,  and  many  ingenious  methods  for  so  doing 
have  been  devised  ;  some  of  these  necessitate  the 
use  of  specially  formed  instruments,  and  are  in 
consequence  not  so  convenient  of  application,  for 
the  occasions  on  which  they  can  be  used  are  of 
necessity  limited.  In  those  cases  in  which  the 
fracture  of  the  bridge  has  taken  jalace  right 
through  the  body  of  the  piece,  owing  to  faulty 
soldering  or  uisufficient  strength  of  metal,  it 
is  necessary  to  remove  the  whole  bridge  and 
resolder,  or  in  most  cases  remake ;  but  very 
often  the  gold  wears  through,  if  soft  gold  in- 
sufficiently reinforced  has  been  used,  and  a 
repair  can  then  be  effected  by  inserting  a  gold 
filling    at    the    weak    pomt.     The    commonest 


627 


form  of  fracture,  however,  is  the  broken  facing, 
and  the  chief  methods  of  repair  will  be  given, 
presupposing  of  courae  that  it  is  not  desirable 
to  remove  the  bridge,  and  as  a  rule  that  is  what 
one  does  not  wish  to  do. 

In  the  case  of  a  broken  premolar  or  incisor 
facing,  and  where  there  is  a  good  thickness  of 
gold,  the  following  method  is  one  of  the  most 
satisfactory. 

The  remainder  of  the  facing  is  removed,  leaving 
the  pins  in  position  in  the  gold ;  the  puis  are 
then  cut  flush  with  the  backing,  and  with  spear- 
head and  rose-head  burrs  dipped  in  oil  the  pins 
and  intervening  gold  are  cut  away,  and  a  hole 
is    made    ui    the     backing    about     ^V    of    an 


-A- 


ta 


V^ 


Fi(i.  835. 


inch  deep,  or  more  if  the  backing  allows  of  it 
(see  Fig.  835),  but  the  hole  must  be  made  right 
through  the  gold ;  the  width  of  the  hole  must 
be  kept  only  slightly  wider  than  the  pins  of  the 
new  facing  ;  this  new  facing  having  been  selected, 
the  pins  are  made  quite  parallel,  and  the  facing 
is  put  in  place,  the  pins  going  as  far  into  the 
hole  as  the  depth  of  it  «ill 
allow.  The  facing  being  correct 
as  to  thickness,  etc.,  i.  e.  so 
that  when  later  on  it  is  tight 
up  against  the  backing  it  will 
not  be  too  prominent,  it  is  laid 
aside,  and  the  gold  is  hollowed 
out  (or  under-cut)  laterally,  to 
a  distance  on  each  side  of 
about  .'.r  of  an  inch  or  more 
(see  Fig'.  836).  The  pins  of  the 
facing  are  flattened  and  the 
ends  bent  at  right  angles  (see 
Fig.  837,  transverse  section). 
One  pin  is  made  slightly  shorter 
than  the  other,  and  by  putting 
the  long  pin  in  the  opening  and  pressing  it  side- 
ways, the  short  pin  wiU  also  be  enabled  to  pass 
into  the  opening,  and  the  facing  cannot  then 
pull  out  ui  a  direct  forward 
line  (see  Figs.  838  and  839). 
The  hole  and  under-cuts  hav- 
ing been  made  sufficiently 
large,  the  porcelain  ^^ill  go 
right  up  against  the  backing. 
It  must  be  ascertained  now  that  the  fit  is  good  ; 
if  the  back  of  the  facing  is  quite  flat,  and  in  good 
pin-teeth  it  usuaOy  is  (except  just  round  the 
pins,  which  does  not  matter),  and  if  the  backing 
itself  has  not  been  bent  by  attrition,  etc.,  it  will 
be  found  that  very  little  fitting  is  needed,  but 


Fig. 836 


A,  Undercut  part 
of  gold  back- 
ing ;  B,  Hole 
into  backing ; 
C,  Gold  back- 
ing. 


in  some  cases  a  little  grinding  of  the  backing  is 
necessary. 

The  facing  havmg  been  ground  for  the  "  bite  ", 
the  glaze  is  taken  off  the  back  -with  a  stone,  the 
backing  roughened  slightly  with  a  burr,  and  the 
pin  then  cemented  into  place  with  an  oxy- 
phosphate  cement,  a  very  strong  and  serviceable 
repair  bemg  effected. 

In  order  to  shorten  the  work  in  the  mouth, 
an  impression  may  be  taken  of  the  surface  of 
the  broken  backing,  and  after  a  model  has  been 
cast  in  metal  or  cement  it  may  be  cut  out  exactly 
as  it  will  be  in  the  mouth,  and  the  facing  may 
then  be  accurately  fitted  to  this  model,  only  the 
actual  fitting  of  the  gold  being  left  to  be  done 
in  the  mouth.  This  method  also  helps  one  by 
showing  exactly  where  to  cut  the  hole  in  the 
gold,  and  about  what  size  to  make  it. 

Another  method  is,  as  follows  :  Firstly,  the 
pins  of  the  broken  facing  are  cut  flush  as  in 
the  previous  method,  and  then  a  cast  is  made  ; 
the  pins  of  the  new  facing  are  then  made 
exactly  parallel  and  passed  through  two  holes 
made  in  the  metal  cast  in  such  a  position  that 
they  allow  of  the  facing  being  fitted  properly 
to  the  cast.  After  this  has  been  done  a  back- 
ing is  made  of  paper  to  fit   the   new  facing. 


Fig.  838. 


Fig.  839. 


with  holes  exactly  fitting  the  pins ;  this  back- 
ing is  taken  off  the  facing  and  transferred 
to  the  backing  in  the  mouth,  the  holes  in  the 
paper  showing  exactly  where  to  drill  the  holes 
in  the  gold;  this  is  done  by  means  of  spear- 
pointed  drills,  care  being  taken  to  keep  them 
quite  parallel,  and  the  holes  must  go  right 
through  the  gold.  Notice  should  be  taken  that 
the  pins  project  on  the  lingual  side  of  the  gold 
to  allow  of  their  being  bent  together  over  it, 
and  then  a  groove  should  be  cut  on  the  lingual 
surface  joining  the  two  holes.  After  the  tooth  is 
cemented  into  place  it  is  firmly  held  while  the 
cement  is  soft,  and  with  pliers  the  two  pins  are 
bent  together  in  the  groove  prepared  for  them ; 
they  are  then  burnished  down  lightly  and 
smoothed  over  with  a  stone. 

Instead  of  the  pins  being  bent  over  to  hold  the 
facing  in  place  they  may  be  riveted  by  means  of 
a  plate  punch,  the"  lingual  ends  of  the  two  holes 
having  hrst  been  countersunk.  This  makes 
a  very  firm  repair,  but  it  is  difficult  to  do  the 
riveting  properly  ;  it  is  best  in  so  doing  to  have 
only  just  as  much  extra  length  of  pin  as  is  re- 
quired, and  to  start  by  very  slightly  grooving 
the  ends  of  the  pin  with  a  knife. 

Outfits    are    supplied    by    the    depots    for 


628 


Fig.  840. 


threading  the  pins,  and  securing  them  to  the 
backing  by  means  of  a  cone-shaped  nut,  which 
is  screwed  home  into  the  two  holes  from  the 
lingual  side,  the  holes  having  been  enlarged 
and  made  cone-shaped  to  receive  the  nuts ; 
this  method  is  very  often  inapplicable,  and  the 
weak  point  of  it  is  that  the  threading  of  the  pins 
must  necessarily  weaken  them  very  much. 

A  useful  method  of  repairing  a  facing  in  those 
cases  «heie  the  backing  is  thin,  owing  to  the 
"  bite  '".  is  as  follows  :  The  pins  are  ground  flush 
with  the  backing ;  then  with  a  spear-pointed 
drill  two  holes  are  made  right 
through  the  backing  in  the 
exact  position  of  the  two  pins 
(see  Fig.  840) ;  these  holes  are 
converted  into  grooves  by 
means  of  fissure-burrs,  as  shown 
by  the  dotted  lines  in  Fig.  840. 
A  facing  is  selected,  and  the  pins 
hiving  been  made  parallel,  it 
is  slipped  into  jjlace,  the  pins 
resting  in  the  bottom  of  the  grooves  and  going 
right  through  the  thickness  of  the  backing,  and 
being  allowed  to  project  considerably  on  the 
lingual  side  ;  if  the  backing  is  too  thick  for  the 
pins  so  to  project,  it  is  stoned  down  from  the 
lingual  side  until  the  condition 
is  effected ;  a  sectional  view 
would  appear  as  in  Fig.  841. 
The  facing  having  been  properly 
adjusted  as  to  fit,  bite,  etc.,  and 
])lenty  of  room  having  been  left 
between  the  occluding  teeth  and 
the  lingual  surface  of  the  stoned- 
down  backing,  a  piece  of  thin 
soft  platinum  (about  inW  oi  an 
inch  in  thickness)  is  cut  to  size, 
and  the  facing  being  held  in  position,  the 
platinum  is  pressed  against  the  lingual  surface  of 
the  backing,  the  pins  are  forced  through  it,  and 
it  is  roughly  adapted  to  the  backing.  The  pins 
are  secured  to  the  platinum  by  a  little  hard  wax 
apphed  to  their  ends  where  they  emerge  from 
the  platinum ;  the  platinum  backing  or  foil  is 
then  cut  to  the  proper  size  and  closely  adapted 
to  the  gold  backing  by  burnishing,  and  brought 
to  the  cutting  edge  of  the  tooth.  \Vlien  this  has 
been  done  more  wax  is  flowed  over  the  whole 
lingual  surface  of  the  platinum  (the  tooth  and 
platinum  being  removed  for  this),  and  it  is  then 
replaced,  and  while  the  wax  is  fairly  soft  held 
in  close  apposition  everywhere  until  cold ;  it  is 
then  thoroughly  chilled,  removed,  and  invested, 
and  a  high  carat  gold  is  flowed  over  the  lingual 
surface  to  replace  the  wax,  and  so  make  a  solid 
diaphragm.  The  facing  and  diaphragm  are 
then  cemented  into  place  with  a  good  hy- 
draulic cement,  the  surfaces  of  the  gold  having 
been  thoroughly  dried  and  roughened.  This 
process    makes    a    serviceable    repair    and    is 


Fig.  841. 


quickly  done,  but  should  not  be  employed  if  a 
more  thorough  method  can  be  used. 

Ash's  mineral  teeth  can  often  be  used 
advantageously ;  they  are  practically  ordinary 
facings  made  in  the  shape  of  flat  teeth,  but  in 
lieu  of  pins  they  have  an  oval  cavity  in  the 
porcelain,  which  corresponds  to  the  position  of 
the  pins,  and  where  the  pins  are  left  standing 
in  the  backing,  a  suitable  tooth  is  selected  and 
cemented  into  place  with  an  oxy-phosphate 
cement. 

PORCELAIN    BRIDGES 

In  considering  the  question  of  porcelain  bridge- 
work,  it  is  necessary  to  remember  that  its 
application  is  strictly  limited. 

The  comparative  ease  with  which  porcelain 
will  fracture  under  strain  and  stress  requires 
that  in  a  given  case  there  must  be  no  mis- 
judgement of  all  the  forces  it  will  be  called 
upon  to  bear ;  everything  must  be  considered — 
the  articulation,  the  occluding  teeth,  whether 
natural  or  artificial,  and  as  nearly  as  can  be  ascer- 
tained the  amount  of  force  exerted  in  the  normal 
movements  of  mastication.  Now  this  is  very 
difficult  to  gauge ;  in  ordinary  bridge-work, 
doubt  as  to  strength  can  be  removed  by  rein- 
forcing Hkely  points  of  weakness  by  means  of 
more  metal,  but  with  porcelain  this  is  not 
possible  in  the  same  way,  for  the  requisite 
strength  can  only  be  obtained  by  having  the 
iridio-platinum  base-work,  on  which  the  porce- 
lain is  fused,  sufBciently  strong  of  itself  to  with- 
stand all  the  likely  force  ;  this,  of  course,  neces- 
sitates ample  room  between  the  abutments  and 
the  opj)osing  teeth,  and  this  is  just  \\hat  is  not 
usually  obtainable  in  what  would  otherwise 
be  suitable  cases  for  the  work.  Then  again, 
allowing  that  the  necessary  strength  of  base 
has  been  obtained,  it  must  not  have  been  done 
by  encroaching  on  the  space  required  for  the 
proper  amount  of  porcelain  body,  for,  in  apply- 
ing the  body,  everything  must  be  so  arranged 
that  in  the  finished  piece  the  piorcelain  is  not 
intersected  by  the  underlying  base  at  points 
where  the  continuity  of  the  porcelain  is  essential 
for  strength. 

The  possibility  of  the  repair  of  a  bridge  must 
be  taken  into  consideration ;  it  may  be  safely 
said  that  no  porcelain  bridge  should  be  put  in 
the  mouth  fixed  by  cement  alone — that  is,  no 
so-called  fixed  bridge ;  cement  combined  with 
gutta-percha,  or  gutta-percha  "  cement  ",  should 
always  be  used,  for  the  enormous  difficulty  of 
removing  a  bridge  cemented  in  the  ordinary 
way  absolutely  contra-indicates  it,  so  that  if  for 
any  reason  it  is  considered  that  gutta-percha  can- 
not bo  used  another  form  of  \\ork  is  desirable. 

Comparative  Value  of  Fixed  and  Removable 
Porcelain-work.  —  The  same  points  for  con- 
sideration arise  when  deciding  the  advisability 


629 


of  making  a  piece  removable  or  fixed  in  porce- 
lain-work, as  arise  ^^•hen  ordinary  bridge-work 
is  being  considered  (and  having  been  dealt  with 
in  the  earUer  part  of  this  chapter  need  only  be 
slightly  touched  upon  here),  but  in  addition  it 
must  be  remembered  that  it  is  much  more 
difficult  to  work  in  iridio-platinum  and  platinum 
solder  than  it  is  in  gold,  and,  as  has  been  seen 
when  considering  repairs,  a  "fixed  "  piece  must 
not  be  permanently  fixed  in  the  mouth  by 
ordinary  cement  alone ;  thus  it  often  happens 
that  in  the  front  of  the  mouth  a  fixed  bridge  put 
on  with  gutta-percha  will  be  preferable  to  a 
"removable"  one,  and  occasional  removal  by 
the  dentist  for  thorough  cleansing  purposes  is 
of  course  highly  desirable. 

On  the  other  hand,  in  bridges  at  the  side  of 
the  mouth,  say  from  canine  to  first  molar, 
which  of  course  show  very  much,  and  at  the 
same  time  take  a  large  amount  of  the  strain  of 
mastication,  sufficient  strength  is  only  to  be 
obtained  by  the  use  of  a  "  saddle  ",  and  to 
put  a  "  fixed  "  bridge  in  the  mouth  with  a 
saddle  is  as  culpable  in  porcelain-work  as  in 
ordinary  gold-work,  although  some  writers 
(Evans,  Goslee)  maintain  that  the  amount  of 
absorption  that  takes  place  is  negUgible  (if  the 
teeth  have  been  extracted  a  proper  length  of 
time),  and  that  under  jjlatinum  the  mucous 
membrane  simply  becomes  shghtly  hyj^eraemic, 
and  that  the  piece  remains  perfectly  hygienic. 

Thus,  if  the  necessary  strength  can  only  be 
obtained  by  means  of  a  saddle,  a  removable 
bridge  is  indicated. 

Then  again,  if  there  has  been  much  absorp- 
tion, especially  in  the  anterior  part  of  the  mouth, 
a  saddle  becomes  necessary  in  order  that  the 
gum  may  be  properly  reproduced  by  means  of 
the  porcelain. 

Main  Points  in  the  Construction  of  Porcelain 
Bridges 

Fixed. — A  thorough  knowledge  of  the  working 
of  high-fusing  porcelain  and  the  management  of 
platinum  solder  is  essential. 

Iridio-platinum  is  used  (about  10%  iridium), 
about  T^JfjT  to  ^4ttij  thick  for  the  plate,  and 
as  strong  as  possible  for  the  pins.  The  Rich- 
mond cap  and  pin  is  used  wherever  possible  (or 
the  half-cap  and  pm)  on  the  ten  anterior 
teeth,  and  on  molars  a  cap,  also  with  one  or 
more  pins,  as  long  as  can  be  obtained,  going 
into  the  pulp-chamber.  The  soldering  is  done 
by  means  of  platinum  solder,  of  at  least  20  per 
cent.,  and  in  making  the  bands  the  ends  are 
overlapped  for  soldering. 

A  model  with  the  caps  in  position  is  obtained 
as  for  ordinary  bridge- work.  The  facings  are 
selected  and  fitted  and  coaxed  into  place ;  the 
piece  is  removed  from  the  model  and  invested 
in  a  good  strong  investment,  and  the  wax  re- 


moved, the  pins  having  been  left  straight  and 
no  tackmg  used.  An  iridio-platinum  bar,  not 
less  than  No.  1  size  (Ash),  or  16  (American) 
gauge,  is  fitted  so  that  the  ends  (which  have  been 
flattened)  rest  securely  on  the  top  of  the  cap 
and  the  bar  runs  close  to  the  facings  under- 
neath the  pins,  but  not  quite  touching  them  or 
the  facings.  The  pins  are  then  bent  down  on 
to  the  bar  until  they  touch  it ;  if  absolute  con- 
tact is  difficult  to  obtain,  platinum  plate  must 
be  fixed  firmly  between,  the  bar  being  held  in 
position  by  means  of  additional  investment  at 
suitable  points. 

The  whole  is  then  strongly  soldered  with 
platinum  solder,  removed,  and  cleaned,  and  any 
rough  points  of  solder  or  the  edges  of  the  pins 
ground  down,  so  that  it  presents  everywhere  a 
smooth  surface,  when  the  piece  is  ready  for  the 
application  of  the  body.  This  is  done  as  for  a 
single  crown,  high-fusing  body  of  two  different 
fusing  pomts  being  used,  and  the  material 
worked  as  dry  as  possible,  and  in  as  few  bakings 
as  possible. 

If  one  of  the  abutments  is  the  second  pre- 
molar, the  first  premolar  should  be  left  as  a 
facing,  and  no  attempt  made  to  build  out  the 
cusps  of  the  tooth,  as  they  would  only  fracture. 

Removable. — The  chief  abutment  pieces  are 
the  half -cap  and  split  pin.  Taking  a  case  from 
canine  to  canine,  the  caps  are  made  in  the  same 
way  as  for  gold-work,  except  of  course  that  the 
pin  and  outer  caj)  is  made  with  iridio-platinum 
soldered  with  platinum  solder. 

An  iridio-platinum  saddle  is  used,  made  as 
before  described  (in  thickness  j^~  to  yig„  inch), 
and  30  to  32  (American)  gauge,  adapted  to 
the  mouth,  soldered  to  the  outer  caps,  and 
tried  again ;  a  model  is  then  taken,  facings 
are  fitted,  and  a  bar,  between  3  and  4  (Ash), 
or  14  (American)  gauge,  is  fitted  so  that  it 
rests  as  described  for  fixed  work,  on  the  abut- 
ment pieces,  and  between  the  pms  and  the 
saddle,  and  as  near  to  both  as  it  can  be  got. 
A  piece  of  wire  may  be  fitted  along  the  lingual 
edge  of  the  saddle  also,  to  act  as  a  sort  of 
support  for  the  body  during  the  fusing. 

The  piece  is  soldered  strongly,  and  thoroughly 
cleansed,  and  the  body  is  fused  in  the  ordinary 
way. 

Further  back  in  the  mouth,  say,  from  first 
premolar  to  second  molar,  the  method  would  be 
the  same,  except  that  for  the  abutment  pieces 
of  the  molar,  a  strong  iridio-platinum  bar  fitted 
into  a  deep  and  broad  groove  in  either  a  crow  n 
or  inlay  is  preferable  to  soldering  the  bridge 
(after  fusing)  to  an  ordinary  telescope- cap,  be- 
cause even  a  high-grade  solder  does  not  hold 
well  on  platinum,  and  pure  gold  cannot  be  fused 
over  the  contact  point  of  the  platinum  with  the 
cap,  on  to  which  the  solder  would  hold,  as  the 
gold  would  disappear  in  firing  the  high-fusing 


630 


body,  and  a  sufficiently  low -fusing  body  is  not 
strong  enough ;  for  the  same  reason  pure  gold 
cannot  be  used  as  a  solder,  as  was  previously 
taught. 

G.  P.  P. 
BIBLIOGRAPHY 

( 1 )  Betjkton,  G.  a  Kew  Post  for  Crown-  and  Bridge- 
work.  Brit.  Dent.  Jour.,  1906,  Vol.  XXVII, 
pp.  1057,  1105. 


(2)  Campkin,    p.    S.     Brit.   Dent.   Jour.,    1907,    Vol. 

XXVIII,  p.  3. 

(3)  Evans.     Artificial   Crown,  Bridge,   and  Porcelain 

Work,  7th  ed.,  pp.  188  et  seq. 

(4)  GOSLEK.     Principles  and  Practice  of  Crown-  and 

Bridge-work,  3rd  ed.,  1910,  p.  336. 

(5)  GosLEE.     Principles  and  Practice  of  Crown-  and 

Bridge-work,  7th  ed.,  pp.  394,  397. 

(6)  Peeso.     Turner's  Text-book  of  Prosthetic  Dentistry, 

1907. 


CHAPTER  XXXIX 

CAST  SECTIONAL  BRIDGES 


Before  describing  the  technique  in  the  con- 
struction of  cast  sectional  bridges,  it  is  advisable 
to  point  out  some  of  the  advantages  of  this 
method  of  constructing  bridge- 
work — 

1 .  It  is  not  necessary  to  muti- 
late the  teetli  intended  to  serve 
as  abutments. 

2.  The  bridge  can  be  easily 
and  accurately  fitted  to  the 
abutments. 

3.  The  bridge  can  be  so  con- 
structed that  all  parts  can  be 
readily  cleaned. 

4.  The  bridge  can  be  easily 
removed  without  destroying  it. 

5.  The  time  of  the  patient 
and  operator  can  be  economized, 
as  the  greater  part  of  the  work 
can  be  done  in  the  laboratory, 
the  bridge  being  fitted  and  ad- 
justed to  models. 

To  obtain  these  results,  it  is 
absolutely  necessary  that  the  im- 
pressions of  the  spaces  and  the 
abutments  be  accurate,  and  that  the  materials 
of   which  the   models  are  made  be  sufficiently 


taking  Case  1  as  an  example,  and  afterwards 
describing  other  cases  in  practice  to  which  this 
method,  with  slight  variation,  has  been  applied. 


Fig.  842. 


hard  to  withstand  the  friction  and  rough  usage 
to  which  they  are  subjected  in  the  laboratory. 

Herewith  is  given  a  detailed  description  of 
the    method    used    in    making    these    bridges, 


631 


Fig.  843. 

Trays  for  Impressions. — In  most  cases,  an 
impression  of  the  mouth  is  first  taken  in  the 
ordinary  way,  and  special  trays 
are  made  as  in  Fig.  842.  These 
are  cast  in  tin  or  lead  with  a  piece 
of  brass  or  nickel  wire  embedded 
to  form  a  handle,  A. 

Impressions. — The  impression  is 

then  taken  in  plaster  of  Paris  in 

two  halves — lingual  surface  first. 

The  plaster  in  the  lingual  half  is 

allowed  to  set,  and  is  then  trimmed 

in  the  mouth,  until  only  the  lingual, 

and   half   the    medial   and  distal, 

surfaces  are  covered,  Fig.  843,  A, 

so    that   the    buccal    half   of   the 

impression  B  will  \nthdraw  easOy. 

When    this    has    been    done,    the 

surface  is  vaselined,  and  the  buccal 

half    of    the    impression    is    then 

taken.     A  little  aniline  colour  is 

used  in   one   of   the   mixings  to   facilitate   the 

assembling   of  the  parts  together.     When  the 

two  halves  are  withdrawn,  they  must  be  secured 

firmly  together  with  sealing  wax,  and  a  low- 


63;] 


fusing  alloy  poured  in  to  form  the  model.  After 
the  model  has  been  cast,  it  should  be  compared 
with  the  mouth,  and  trimmed  where  necessary. 
An  impression  of  the  antagonizing  teeth  should 
be  taken,  and  correct  occlusion  ascertained  at 
the  same  visit. 

A  saliva  ejector  is  useful  to  assist  in  keeping 
the  mouth  dry  whilst  the  impression  is  being 
taken.  By  taking  the  impression  in  this  manner 
all  risk  of  dragging  is  eliminated,  and  however 
undercut  the  teeth  may  be,  a  correct  result  is 
obtained. 

Metliod  of  Preparing  Wax  Patterns  for  Casting. 
It  is  usually  the  best  plan  to  make  the  lingual 
half  of  the'bridge  first,  as  in  Fig.  844,  A,  with 
articulating  surfaces  formed  ;  carbon  points  are 
inserted  where  screws  (1)  and  locking-pin  (2) 
are  intended  to  be.     (See  Case  1,  Fig.  846,  A 


Fig.  844. 

and  B.)  If  porcelain  facings  are  to  be  used, 
these  should  be  fitted  to  the  model  and  carefully 
removed  from  the  wax  mould,  and  carbon 
points  inserted  where  the  pins  have  been  (3). 
The  porcelain  faces  can  then  be  cemented  in 
when  the  bridge  is  complete.  This  half  should 
be  quite  finished  and  polished,  the  holes  tapped, 
and  the  screws  fitted. 

Wlien  that  is  done,  the  buccal  half  is  built 
up,  as  in  B,  Fig.  844,  with  the  impressions  of 
screw-heads  (4)  and  hole  for  locking-pin  (5) 
formed  in  the  wax  mould.  A  carbon  point  is 
put  in  the  hole  for  the  locking-pin,  but  the 
holes  for  the  screw-heads  are  filled  up  with 
investment  material.  The  form  and  position 
of  sprues  are  shown  at  (6).  The  buccal  half  is 
then  cast,  and  a  locking-pin  (see  Case  1,  Fig. 
846,  C)  soldered  to  it. 


Fig.  S45. — Case  1. 


■SEC"    inn     SH'^v^irif^ 

^  1  »if^->^^SEfs»>^<n^S 

Ib      I 

^^^KmSISfx  ^^^"V^'v-Ti^f^.SkSS 

L 

FL^NGE. 

n 

^^^ 

J 
i 

> 

-                                t      L0CKIM(^     Pin 

Fig.  84(). — Case  1. 


Fig.  847.— Case  1. 


633 


Case  1. 

This  is  a  case  where  the  lower 
lateral,  second  premolar,  and  first  and 
second  molars  are  absent.  A  porcelain 
facing  is  fitted  to  replace  the  lower 
lateral  in  the  lingual  half  of  the  bridge  ; 
the  buccal  half  is  secured  to  the  lingual 
half  by  two  screws,  and  a  locking-pin 
between  the  screws.  All  ■pressure  is 
taken  off  the  screws  by  extending  the 
articulating  surface  as  a  flange  over 
the  upper  portion  of  the  buccal  half 
(Fig.  846),  and  lateral  stress  resisted 
by  the  locking-pin  (Fig.  846).  In  this 
case  the  lower  premolar  is  very  carious, 
so  it  is  built  up  and  covered  with  a 
gold  cap.  A  lug  is  soldered  on  the 
distal  side  to  prevent  the  bridge  being 
driven  down  by  the  force  of  masti- 
cation, or  raised  by  the  action  of  the 
tongue. 

Fig.  845  shows  model  with  crown 
on  premolar. 

Fig.  846  shows  the  lingual  half 
finished  and  fitted  to  the  model.  A; 
the  same  apart  from  the  model,  B ; 
and  the  buccal  half  completed,  with 
locking-pin  soldered  to  it,  C. 

Fig.  847  shows  the  completed  bridge 
on  model  with  porcelain  face  cemented 
at  (1). 


Vir..  840.— Case  2. 


Fig.  850.— Case  2. 


Case  2. 

Fig.  848.  Molar  crowned,  with  lug 
on  medial  surface,  and  centre  portion 
cast  to  fit  over  lug  and  lower 
premolar. 

Fig.  849  shows  the  lingual  half  in 
position  on  the  model  A,  and  off  the 
model  13.  In  this  case  the  locking-pin 
is  in  the  lingual  half. 

Fig.  850  shows  the  bridge  in 
position. 


Fi.!.  848.— Case  2. 


634 


Fig.  851.— Case  3. 


Case  3. 

Bridge  to  fill  up  space  between  first  lower 
premolar  and  third  lower  molar. 

In  this  case  the  articulation  of  the  molar 
does  not  allow  of  its  being  wholly  covered, 
and  the  distal  surface  of  the  premolar  is 
too  nearly  vertical  to  retain  the  bridge  in 
position,  so  a  shallow  groove  is  cut  in  the 
distal  surface  of  the  premolar,  and  the 
molar  is  covered  as  much  as  the  bite  will 
allow. 

Fig.  851  shows  the  model  with  groove  cut 
in  the  lower  premolar  (1), 

Fig.  852  shows  the  lingual  half  in  position, 
A,  and  off  the  model,  B,  and  the  buccal 
half  ready  for  fixing,  C. 

Fig.  853  shows  the  bridge  completed  and 
in  position. 


Fici.  8.52.— Case  3. 


853.— Case  3. 


Fig.  854. — Case  4. 


635 


Fic;.  857 


-Case  5. 


Fig.  S55. — Case  4. 


Fig.  858. — Case  5. 


Fig.  850. — Case.  4. 


Case  4. 

Fig.  854.  Model.  This  case  is  typical  of  what 
is  met  with  in  everyday  practice.  The  space 
has  been  vacant  for  some  time,  and  there  is 
considerable  tilting  of  the  lower  molar  and 
premolar.  The  two  halves  are  secured  by  a 
strong  screw,  and  lateral  movement  is  pre- 
vented by  a  square  groove,  Fig.  855  (1),  cast 
in  the  hngual  half,  into  which  the  buccal  half 
is  keyed. 

Fig.  856  shows  the  bridge  in  position. 


Fig   859. — Case  5. 


636 


Case  5. 

Fig.  857.  Model.  This  is  a  somewhat  simOar 
case  to  the  last,  but  the  abutments  are  much 
shorter.  In  this  case  the  molar  is  covered  by 
the  bridge,  and  the  two  halves  are  secured  by 
a  single  screw,  Fig.  858  (1),  and  a  locking-pin, 
Fig.  858,  (2)  prevents  lateral  movement. 

Fig.  859.     Completed  case. 


Fig.  SG2. — Case  G. 


Fig.  SUU. — Case  U. 


Case  6. 

!       Fig.  860.     Model. 

Fig.  861.     Similar  to  the  last,  but  more  teeth 
are  absent. 

The  lingual  half  covers  the  greater  part  of  the 

molar  abutment. 

i 

I       The  two  halves  are  secured  by  two  screws  and 
a  locking-pin. 

Fig.  862.     Completed  case. 


Fig.  861.— Case  6. 


Fig.  863.— Case  7. 


fi:?7 


Fig.  865.— Case  7. 

Case  7. 

Fig.  863.  Model.  This  is  a  useful  method  of 
replacing  a  lower  incisor  and,  at  the  same  time, 
supporting  adjacent  teeth. 

The  impression  is  taken  in  two  halves,  as 
described  in  Case  1. 

The  lingual  half  is  cast  first  with  a  porcelain 
tooth  in  position  as  described  in  Case  1,  Fig.  864. 
To  prevent  lateral  movement  a  boss  is  shaped 
as  in  Fig.  864  (1).  This  half  is  finished  and 
polished,  and  then  the  pattern  for  the  labial 
portion  is  adapted  to  it,  with  the  hole  for 
screw-head  moulded  in  and  filled  with  a  car- 
bon point  (2). 

The  method  of  keying  the  two  halves  is  shown 
at  (3),  Fig.  864. 

Fig.  865  shows  bridge  in  position. 


Case  8. 

Figs.  866  and  867  represent  a  retaining  appli- 
ance for  loose  lower  incisors,  made  in  a  similar 
way,  and  secured  by  two  scre\\s  passing  between 
the  teeth. 


S(i8. — Ca 


638 


Fig.   S70.— Case  9. 


Fig.  871. — Case  <». 


Case  9. 

Fig.  868.  This  is  a  modification  of  the  method 
described,  and  is  more  suitable  for  upper  cases, 
where  it  is  desirable  to  avoid  showing  gold. 

The  space  to  be  filled  is  from  the  first  pre- 
molar to  the  second  molar.  The  first  premolar 
is  cut  do^vn  level  \vith  the  gum  margin,  and  a 
strong  pin  fitted  in  the  root.  A  pattern  in  wax 
is  then  fitted  over  the  face  of  the  root,  Fig.  868 
(1),  and  cast  on  to  the  pin.  This  is  shaped  and 
finished  as  in  (1)  and  (lA). 

An  impression  is  taken  in  two  halves,  as  in 
Case  1,  and  the  model  made  in  the  usual 
way. 

The  porcelain  faces  are  then  fitted,  and  the 
wax  pattern  for  the  buccal  portion  made  first, 
as  in  A,  Fig.  869.  Carbon  points  are  inserted 
where  the  screws  are  intended  to  be.  Fig.  869  (1) ; 
the  porcelain  faces  carefully  removed  from  the 
wax  pattern ;  and  carbon  points  inserted  where 
the  pins  have  been.  Fig.  869  (2).  This  half  is  then 
cast,  screws  are  fitted,  and  the  piece  is  finished 
and  polished,  A,  Figs.  870  and  871. 

The  pattern  for  the  palatal  portion  is  then 
made  as  in  B,  Fig.  871.  The  two  halves  are 
secured  by  two  screws  through  the  palatal 
half. 

The  completed  case  in  position  is  shown  in 
Figs.  872  and  873. 


639 


Various  Practical  Points. — A  hard  gold  18- 
carat  alloy  should  be  used.  The  screws  should 
be  made  of  a  hard  metal,  such  as  platinum- 
iridium  or  12-carat  gold.  In  practice,  the  latter 
has  proved  very  satisfactory.  They  can  be 
cut  out  of  the  solid  wire  by  using  special  cutters, 
such  as  are  supplied  to  watchmakers.  A  small 
watchmaker's  lathe,  such  as  the  Lorch,  is  very 
useful  for  this  work. 

The  most  suitable  screw-cutting  appliances 
are  Card's  Diamond  Screw-plates,  ^^■ith  taps 
and  dies  to  conform  to  the  British  Association 
Standard.  The  useful  sizes  are  9  to  14  inclu- 
sive. Morse  drills  to  correspond  with  these  sizes 
should  be  used  to  enlarge  the  lioles  before  tap- 
ping, as  better  results  are  obtamed  by  using  the 


carbon  cores  a  size  smaller  than  the  screws  are 
intended  to  be. 

The  carbon  points  can  be  obtained  from  any 
good  stationer. 

Cementing  the  Bridge  in  Position. — The  two 
halves  are  comiected  by  engaging  the  screws  in 
a  few  threads  only,  thus  facilitating  the  placing 
of  the  bridge  in  position.  All  surfaces  intended 
to  come  in  contact  \vith  the  abutments,  are 
covered  mth  cement,  care  being  taken  to  avoid 
the  cement  coming  in  contact  with  the  screws. 

\Vlien  the  two  halves  are  connected  it  is  a 
simple  matter  to  place  the  bridge  in  position, 
and  the  operation  is  completed  by  driving  the 
screws  home. 

E.H. 


CHAPTER  XL 


EXTRACTION   OF   TEETH 


Extraction  of  a  tooth  or  of  teeth  is  one  of 
the  few  remamiiig  operations  of  surgery  calling 
for  the  possession  of  such  a  degree  of  skill  and 
dexterity  on  the  part  of  the  operator  as  will 
enable  him  to  act  with  celerity  as  well  as 
certitude.  It  is  true  that  any  operation  is 
quickly  enough  done  that  is  well  done,  but 
the  conditions  attendant  on  this  particular 
procedure  are  pecidiar,  and,  speaking  generally, 
render  rapidity  in  its  execution  eminently 
desirable.  Thus  it  is  frequently  done  with- 
out any  anaesthetic,  or  with  a  local  anaesthe- 
tic, and  in  either  of  these  cases  the  dentist 
should  endeavour  to  shorten,  so  far  as  possi- 
ble, the  period  of  the  patient's  bodily  anguish 
or  mental  perturljation.  If  a  general  anaesthe- 
tic is  employed,  it  is  usually  one  affording 
a  short  available  anaesthesia,  so  that  quick- 
ness and  skill  are  essential  if  the  operation  is  to 
be  completed  before  the  patient  returns  to  con- 
sciousness. None  the  less,  as  Moynihan  has 
said  :  "  Speed  should  be  the  achievement,  not 
the  aim  of  the  operator." 

Consideration  for  his  patient  and  regard  for 
his  own  reputation  should  stimulate  every 
practitioner  to  perfect  himself  in  the  technique 
of  extraction. 

It  wiU  be  well  in  the  first  place  to  consider 
what  the  conditions  are  that  may  call  for  the 
removal  of  teeth.  The  broad  proposition  may 
be  laid  down  that  any  tooth  that  is  non-func- 
tional and  incapable  of  restoration  to  functional 
activity,  or  causes  pain  or  marked  discomfort 
and  is  not  amenable  to  treatment,  or  is  septic 
and  cannot  be  made  aseptic,  should  be  ex- 
tracted. The  dictum  of  Smale  and  Colyer, 
"No  teeth  are  better  than  septic  teeth,"  is  a 
wise  pronouncement,  which  should  be  ever 
present  to  the  mind  when  one  has  to  decide,  in 
respect  to  any  tooth,  for  conservation  or  extrac- 
tion. A  more  detailed  examination  of  the 
conditions  calling  for  extraction  reveals  the 
extraordinary  number  of  pathological  changes 
that  depend  upon  diseases  of  the  teeth  as  a 
primary  or  contributory  cause.  Teeth  may  of 
course  require  to  be  extracted  from  either  the 
deciduous  or  permanent  dentition ;  in  the  case 
of  the  former,  undue  retention,  extensive  caries, 
and  sepsis,  are  the  commonest  conditions 
demanding  extraction ;  in  the  case  of  the  latter 
it  will  be  necessary  to  enumerate  a  long  list  of 


affections,  some  of  which  may  be  associated  also 
with  diseased  deciduous  teeth. 

Conditions  Calling  for  Extraction. — The  imme- 
diate relief  of  pain  from  inflammation  of  the 
pulp,  or  periodontal  membrane,  or  from  pulp- 
stone  ;  extensij/e  caries,  alveolar  abscess,  sepsis, 
abscess  of  the  maxillary  or  other  accessory 
sinuses ;  post-exanthematous  necrosis,  syphilis, 
epuhs,  polypus,  glossitis,  leukoplakia ;  ulcera- 
tion of  the  tongue,  cheek,  or  lips ;  maUgnant  dis- 
ease; pyorrhoea  alveolaris,  alveolar  osteitis  or 
osteomyelitis.  Supernumerary,  unsightly,  or 
deformed  teeth ;  irregularity,  overcrowding,  or 
malocclusion ;  interference  with  articulation, 
impaction  (commonest  ^dth  third  lower  molars, 
and  sometimes  associated  with  trismus),  acci- 
dental fracture  or  splitting  of  a  tooth,  extrusion, 
looseness,  salivary  calculus.  The  preparation 
of  the  mouth  for  the  insertion  of  dentures ; 
the  effective  removal  of  septic  crowns  or 
bridges.  General  sepsis  associated  with  dead 
or  abscessed  teeth  or  roots. 

Extraction  is  frequently  required  for  the  relief 
of  conditions  arising  from  or  comiected  with 
dental  disease.  As  the  result  of  the  emigration 
or  conveyance  of  septic  material  from  the  teeth 
to  adjacent  or  remote  parts  there  are  :  tonsillitis, 
pharyngitis,  lymphadenitis,  neuritis,  gastritis, 
appendicitis,  pernicious  anaemia,  anaemia  and 
general  debility  or  malnutrition.  So  too,  as 
the  result  of  reflex  nervous  irritation,  or  tox- 
aemia, there  are  :  facial  neuralgia,  cranial  neur- 
algia, neuralgia  affecting  remoter  parts,  chorea, 
epilepsy,  facial  paralysis,  trismus,  torticollis, 
histrionic  spasm,  hysteria,  neurasthenia,  mania, 
amaurosis,  glaucoma,  mydriasis,  strabismus, 
ptosis,  corneal  ulcer,  keratitis  and  possibly 
many  other  ocular  affections,  otalgia,  otorrhoea, 
deafness,  nasal  catarrh,  coryza,  and  some  skin 
diseases,  e.  g.  herpes  and  psoriasis.  In  all  of 
these  extraction  of  teeth  may  be  the  appropriate 
treatment. 

Extraction  may  become  necessary  in  cases  of 
excessive  or  painful  erosion  or  abrasion,  exo- 
stosis, or  absorption  of  roots ;  as  a  prophylactic 
measure  in  phosphorus  workers;  as  a  prelim- 
inary to  excision  of  the  jnaxilla  or  mandible ; 
to  facilitate  the  introduction  of  a  tube  for  the 
conveyance  of  liquid  nutriment  in  cases  of 
trismus,  tetanus  or  anchylosis  of  the  mandi- 
bular articulation ;  in  cases  of  purpura,  hyper- 
040 


641 


trophy  of  the  gum  or  acromegaly ;  and  in  the 
removal  of  dental  cysts  and  odontomes. 

General  Principles  of  Extraction. — The  object 
of  the  operator  is  the  removal  of  the  tooth  from 
its  bony  socket  with  the  minimal  disturbance  or 
injury  of  the  bone,  and  without  destruction  or 
laceration  of  the  soft  parts.  This  is  usually 
effected  by  forceps,  and  the  principle  on  which 
the  use  of  the  instrument  is  based  is  as 
follows — 

The  roots  (or  root)  of  the  tooth  are  grasped 
by  the  blades  of  the  forceps,  the  points  of  which 
are  pushed  or  driven  with  firm  and  steady 
pressure  weU  beyond  the  neck  of  the  tooth, 
the  gum  and  periodontal  membrane  being 
pushed  aside  or  stripped  away  as  the  sharp 
blades  go  home.  The  handles  are  compressed 
and  the  tooth  becomes,  as  it  were,  an  integral 
part  of  the  forceps.  Tooth,  forceps,  the  hand, 
wrist,  forearm,  upper  arm,  and  shoulder  girdle 
of  the  operator,  now  constitute  one  long  rigid 
bar  or  lever,  the  conical,  bifid  or  trifid  extremity 
of  which  is  embedded,  fastened,  and  cemented, 
in  a  rather  dense  but  also  some\^'hat  yielding 
and  elastic  medium.  In  the  case  of  the  upper 
jaw  the  fixed  extremity  is  in  the  long  axis  of 
the  lever ;  in  the  lower  jaw  the  fixed  end,  i.  e. 
the  tooth,  is  embedded  almost  at  right  angles 
with  the  long  axis.  Regarded  thus,  the  problem 
of  how  to  extricate  the  distal  extremity  of  the 
lever  from  its  surroundings  resolves  itself  into 
a  determination  of  the  method  by  which  the 
most  economical  application  of  force  in  the 
direction  of  least  resistance  will  effect  a  solution 
of  continuity  between  the  end  of  the  lever  and 
the  strvicture  in  which  it  is  lodged.  The  method 
will  vary  with  the  shape  and  situation  of  the 
end  of  the  lever,  but  the  principle  enunciated 
remains  constant. 

Particulars  must  be  given  for  the  different 
teeth ;  but  as  a  broad  proposition  it  may  be 
laid  down  that  the  upper  incisors  and  canines 
are  rotated,  with  a  slight  outward  movement  if 
necessary ;  the  upper  cheek-teeth  move  out- 
wards and  do\rawards,  and  all  the  lower  teeth, 
with  the  occasional  exception  of  the  third 
molar,  move  outwards  and  upwards  durmg 
extraction. 

The  late  Sir  John  Tomes  was  the  first  dentist 
to  devise  efficient  extracting  forceps.  He 
insisted  that  these  forceps  should  embrace  as 
much  as  possible  of  the  lingual  and  labial 
aspects  of  the  tooth  at  its  neck ;  that  the  jaws 
should  present  an  inclined  plane  terminating 
in  an  edge ;  and  that  the  length  of  the  jaws 
should  on  no  account  be  greater  than  is  neces- 
sary to  allow  sufficient  space  for  the  reception 
of  the  crown  and  the  neck  of  the  tooth.  He 
also  observed  that  as  the  roots  of  all  teeth  have 
a  general  conical  form,  forceps  when  well  made 
and  applied  should  be  but  as  a  lengthening  of 
21 


the  cone  to  its  base ;  and  that  forceps  should 
be  used  and  constructed  upon  the  jjrinciple 
of  lengthening  the  tooth  for  the  extraction  of 
which  they  are  intended.  He  impressed  upon 
his  students  the  absolute  necessity  of  laying 
hold  of  the  tooth  as  far  down  towards  the  roots 
as  they  could  possibly  get  tlie  instrument,  and 
quoted  with  apjjroval  an  old  and  successful 
operator  as  saying,  "  Push  the  jaws  of  your 
forceps  into  the  sockets  as  tJiough  you  intended 
they  should  come  out  at  the  top  of  the  head  or 
below  the  chin  "  (12)  (13,  pp.  551-554).  The 
statements  are  as  true  and  the  advice  is  as 
good  to-day  as  in  1848. 

The  writer  may  be  permitted  to  observe  that 
in  the  case  of  the  beaked  forceps  commonly 
used  for  molars,  the  presence  of  the  beak  offers 
an  obstacle  to  the  smooth  passage  of  the  blades 
along  the  roots.  Forceps  havmg  a  smooth, 
sharp,  uninterrujjted,  curved  outline  at  the 
extremities  of  the  jaws  can  usually  be  made  to 
slip  under  the  edge  of  the  alveolus  where  it 
embraces  the  neck  of  the  tooth ;  but  the  beak 
of  beaked  forcejjs  impinges  on  the  margin  of  the 
alveolus  and  prevents  the  driving  on  of  the 
forceps  except  at  the  expense  of  slight  fracture 
or  splitting  of  the  alveolar  border,  or  at  least 
of  its  more  violent  displacement.  He  believes 
that  in  practice  these  beaked  forceps  are  seldom 
driven  past  the  neck  of  the  tooth,  which,  indeed, 
they  are  made  to  fit  and  to  which  they  are 
instinctively  adjusted. 

Antiseptic  Precautions. — It  may  be  conceded 
that  it  is  not  possible  to  secure  an  absolutely 
sterile  condition  of  the  field  of  operation  in 
extraction.  But  though  sterilization  or  com- 
plete asejjsis  is  unattainable,  the  dentist  is  not 
absolved  from  the  duty  of  using  such  antiseptic 
precautions  as  are  at  his  disposal.  He  may  be 
unable  to  annihilate  the  micro-organisms  of 
the  mouth ;  he  can,  nevertheless,  reduce  their 
numbers  and  refrain  from  introducing  new- 
comers of  a  j)ossibly  more  dangerous  type.  If 
the  opportunity  occurs,  the  patient  should  be 
instructed  to  attend  carefully  to  the  cleansing 
of  the  mouth  and  teeth  for  some  time  before 
the  operation.  The  use  of  the  tooth-brush 
and  toothpick  should  be  supplemented  by 
frequent  irrigation  and  gargling,  with  a  view 
to  the  promotion  of  asepsis  and  the  pro- 
duction of  a  healthy  condition  of  the  buccal 
mucosa. 

In  the  attempts  made  by  Miller  and  others 
to  sterilize  the  oral  cavity,  mercuric  chloride 
(corrosive  subUmate),  in  a  strength  of  1  in  2500 
of  water,  was  found  to  be  the  most  efficacious 
agent.  The  use  of  this  salt  in  a  mouth-wash  is, 
however,  barred  to  the  dentist  by  reason  of  its 
poisonous  nature.  Sterihzed  boric  acid  solu- 
tion (1  in  40)  or  salicylic  acid  (1  in  300),  is 
useful. 


642 


Carbolic  lotion  (1  in  80)  may  be  used,  or  this 
prescription — 

B  Acidi  Carbolici  .     .     .     .     o  i^^- 
Liquoris  Potassae  .     .     .      3  ^J- 

Aquam  ad 3  i"^- 

Misce,  fiat  collutoriiim. 
Sig. — One  teaspoonful  in  half  a  tumblerful  of 
warm  water  to  be  used  as  a  mouth-wash. 

In  the  writer's  experience  phenol  sodique  is 
of  proved  value  and  may  be  prescribed. 

R  Phenol  sodique  (Boa)     .     .      3  vj. 
Sig. — Two  teasj)oonfuls  in  a  wine-glassful 
of   water   to    be   used   frequently   as   a 
mouth-wash. 

Hydrogen  peroxide,  zinc  chloride,  zuac  sulpho- 
carbolate,  benzoic  acid,  thymol,  saccharin, 
hydronaphthol,  izal,  and  the  essential  oils  of 
cassia,  cimiamon,  and  cloves,  may  be  included 
in  the  list  of  efficacious  antiseptics  suitable  for 
use  in  the  mouth.  Permanganate  of  potassium 
and  Condys  fluid  are  sometimes  used ;  they 
have  the  decided  disadvantage  of  producing  a 
black,  dirty,  messy  appearance. 

All  instruments  should  be  carefully  cleansed 
before  and  after  use  liy  scrubbing  at  a  running 
tap  of  hot  water  wth  a  stiff  brush.  They  must 
then  be  placed  in  the  sterilizer  and  boUed  in  a 
solution  of  potassium  carbonate  (gr.  v  in  5  j) 
for  fifteen  minutes.  For  the  operation  they  are 
placed  ready  to  hand  in  a  dish  or  instrument 
tray  containing  carbolic  lotion  (1  in  40)  sufficient 
to  cover  them.  The  hands  of  the  operator  must 
be  cleansed  and  sterilized.  Dirt  and  loose 
epitheUum  are  got  rid  of  by  washing  and  scrub- 
bing with  a  nail-bnish  and  soap  at  a  stream  of 
hot  water.  The  nails  should  be  carefully  cut 
short.  The  naU-brash  should  be  sterilized  and 
kept  in  1  in  1000  mercuric  chloride.  The  hands 
when  thoroughly  clean  should  be  washed  in 
85  %  alcohol  and  rinsed  in  sterilized  water. 
For  very  septic  cases  with  foul  f)us  present,  or 
for  sjqjhilitic  cases,  the  operator  must  wear 
india-rubber  operating  gloves. 

THE  OPERATION  OF  EXTRACTION 

The  operation  of  extraction  will  be  described 
with  reference  to — 

(1)  The  examination  of  the  patient; 

(2)  The  instruments ; 

(3)  The  position  of  the  patient ; 

(4)  The  positions  of  the  operator; 

(5)  The  introduction  and  application  of  the 

forceps ; 

(6)  The  extraction. 

1.  Examination  of  the  Patient 

This  should  be  conducted  methodically  by  : 
(o)   inquiry,    (b)   inspection,   (c)    palpation,   \d) 


auxihary    means,    e.  g.    probe,    thermal    tests, 
radiography. 

In  many  cases  (a)  and  (b)  wiU  suffice  to 
identify  the  tooth  or  teeth  to  be  extracted, 
and  to  justify  extraction  without  further 
examination,  and  they  should  always  come 
first,  and  should  be  conducted  in  gentle  and 
considerate  fashion.  Nothing  is  more  discon- 
certing to  a  patient  than  to  be  told  to  open  the 
mouth,  and  forthwith  find  the  operator's  hand 
plunged  therein.  Besides,  such  conduct  betrays 
a  want  of  fine  feeling.  The  surgeon's  motto, 
"  Eyes  first,  then  hands,"  should  be  always 
remembered.  Removal  of  dentures  from  the 
mouth  should  accompany  inspection,  and  it 
may  be  necessary  to  wash  or  syringe  out  the 
mouth  with  warm  water  or  antiseptic  lotion. 
Palpation  reveals  the  degree  of  fixity  or  loose- 
ness, and  the  presence  or  absence  of  pain  on 
pressure ;  a  probe,  the  situation  of  a  buried 
root,  the  direction  of  a  sinus,  the  existence  of 
necrosed  bone,  the  definition  of  obscure  edges, 
the  condition  of  the  tooth  qua  soundness,  decay, 
separation  of  roots,  etc. ;  while  in  some  instances 
of  imijaction  or  apparent  suppression  a  radio- 
graph may  be  required  before  the  appropriate 
operative  procedure  is  determined. 

2.  Instruments 

These  are  forceps  and  elevators. 

Forceps  consist  of  blades,  joint,  and  handles. 


Fig.  874. — Curved  Elevators— All  Metal  (writer's 
pattern). 

The  length  and  curve  of  the  blades  should  be 
such  as  to  permit  them  to  accommodate,  with- 


643 


out  touching  it,  tlie  crown  of  the  tooth  to  be 
extracted  when  the  blades  are  adjusted  to  the 
root  or  roots.  The  joint  is  a  strong  pin-joint 
or  hinge.  The  handles  are  serrated  witli  crossed 
serrations  for  the  greater  part  of  their  lengtli, 
to  ensure  a  firm  grip  and  prevent  the  hand  or 
fingers  sHpping.  The  serrations  begin  about 
one  inch  from  the  joint.  The  forceps  are,  over 
all,  6i— 7  ins.  in  length,  but  for  large  hands  may 
be  made  longer.  For  the  anterior  maxillary 
teeth,  handles  and  blades  may  be  made  in  the 
same  straight  line ;  for  uf)per  cheek  teeth,  the 
blades  and  handles  are  just  so  much  curved  as 
to  permit  the  easy  application  of  the  blades, 
and   the    clearance    of   the   anterior    teeth    by 


Fig.  875. — Curved  Elevators — All  Metal  (writers 
pattern). 

the  handles.  For  mandibular  teeth,  the  blades 
are  at  right  angles  to  the  handles.  In  the 
"  hawk's-bill  "  lower  forceps  the  blades  are  so 
placed  that  \Ahen  they  are  applied  the  handles 
are  at  right  angles  to  the  line  of  the  arch  ; 
in  the  "  straight  "  lower  forceps,  when  the 
blades  are  applied  the  handles  are  more  or  less 
in  a  line  with,  or  tangential  to,  the  arch.  The 
"hawk's-bill"  form  is  more  generally  effective, 
and  is  preferred  by  most  operators. 

The  elevator  (.see  Figs.  874,  875)  consists  of 
handle  and  blade.  The  handle,  about  four 
inches  long,  is  serrated  or  cornigated,  and 
whatever  its  shape  it  must  afford  a  firm  grip. 
The  blade  is  about  two  inches  long.  If  the 
handle  is  all  metal  the  blade  is  in  one  piece 
with  it,  but  if  the  handle  is,  as  it  still  is 
sometimes,    of    wood    or    ivory,    a    long    tang. 


the  full  width  of  the  handle,  should  run  the 
whole  length  of  the  handle.  The  point  of  the 
blade  is  rounded  and  its  edge  sharp.  A  spear- 
headed or  beaked  shape  of  point  is  sometimes 
preferred.  Elevators  are  either  straight  or 
curved.  In  both,  the  side  of  the  blade  m 
contact  with  the  tooth  to  be  removed  is  flat  or 
slightly  concave  ;  the  htxek  of  the  elevator  blade 
is  convex.  The  straight  elevator  can  be  used 
on  either  side  of  the  mouth,  but  a  pan-  of  curved 
elevators  is  required. 

3.  Position  of  the  Patient 

The  patient  should  be  seated  in  a  dental  chair, 
in  as  comfortable  and  easy  a  position  as  possible. 
The  head  and  trunk  should  be  in  the  same  line, 
that  is  to  say,  the  neck  should  be  neither  bent 
forward  nor  stretched  backward.  It  is  of  great 
importance  that  the  head  should  never  be 
thrown  far  back  and  the  neck  stretched,  especi- 
ally when  an  anaesthetic  is  given,  as  this  impedes 
both  deglutition  and  respiration.  Besides  this, 
the  risk  of  teeth  or  portions  of  teeth,  loosened 
fillings,  blood  or  jjus,  being  swallowed,  or  worse 
stOl,  drawn  into  the  respiratory  passages,  is 
greatly  increased.  A  dental  chair  of  the  Morri- 
son type,  unencumbered  by  bracket-table  or 
fountain-spittoon  is  the  form  best  suited  for 
the  extraction  operation.  The  chair  should 
be  placed  in  the  best  available  light  before  a 
window.  The  head-rest  should  be  of  such  a 
form  and  be  so  adjusted  as  firmly  to  support 
and  maintain  the  head  in  position.  The  chair 
should  be  slightly  tilted  back.  The  top  of  the 
patient's  head  should  be  about  on  a  level  with 
the  operator's  breast. 

4.  Positions  of  the  Operator 

For  the  maxillary  teeth,  the  operator  stands 
on  the  right  front  of  the  patient,  both  his  thighs 
are  against  the  arm  of  the  chair,  and  the  jjoise 
of  his  tmnk  and  head  is  instinctively  that  best 
adapted  to  secure  a  good  view  of  tlie  parts  to 
be  operated  on  (see  Fig.  87(3). 

For  the  right  mandibular  cheek  teeth,  the 
operator  stands  behind  the  patient,  bending 
his  body  and  head  forward  over  the  patient's 
right  shoulder  to  enaljle  him  to  look  downwards 
and  backwards  into  the  mouth ;  his  left  arm 
surrounds,  embraces,  supj)orts  and  fixes  the 
patient's  head,  the  forefinger  of  his  left  hand  is 
on  the  buccal,  the  thumb  on  the  lingual,  side 
of  the  alveolus  in  relation  to  the  tooth,  and  the 
remainmg  fingers  are  under  the  jaw.  In  this 
way  complete  control  of  the  mandible  is  ob- 
tained. A  kidney-shaped  stool  that  can  be 
placed  beside  the  chair  is  a  great  convenience, 
as  standing  on  it  the  operator  attains  the 
necessary  elevation ;  failing  a  stool,  the  chair 
must  be  lowered  till  the  operator  standing  on 


644 


Fig.  876. 


the  floor  can  assume  the  desired  position  (see 
Fig.  877). 

The  anterior  mandibular  teeth  can  be  taken 
out  with  the  operator  standing  behind,  and  the 
jaw  controlled  in  the  same  way  (see  Fig.  878) ; 
or  the  operator  may  stand  on  the  right  or  left 
front  of  the  patient  grasping  the  alveolus  in 
the  mamier  sho^^ai  (see  Figs.  879,  880).  Some 
operators,  indeed  the  majority,  advise  that  the 
lip  be  kept  out  of  the  way  with  the  forefinger  of 
the  left  hand,  and  the  tongue  with  the  second 
finger,  the  thumb  being  used  to  support  the 
chin ;    but  the  writer  favours  the  principle  of 


Fio.  877. 


Fig.  878. 

always  graspmg  the  alveolus  between  the  finger 
and  thumb  of  the  left  hand  as  giving  a  firmer 
grip,  better  support,  and  more  complete  control. 

For  the  extraction  of  the  left  mandibular 
cheek  teeth  the  operator  has  the  choice  of  two 
positions.  He  may  stand  on  the  right  front, 
with  the  second  finger  of  the  left  hand  on  the 
lingual  side  and  the  first  on  the  labial  side  of 
the  tooth  to  be  extracted,  the  thumb  being 
placed  under  the  chm ;  the  operator  leans 
slightly  across  the  patient  while  extracting. 

The  writer  much  prefers,  and  strongly  advises 
the  operator,  to  take  his  stand  on  the  left  side 
of  the  chair.  His  left  knee  should  be  slightly 
bent,  the  side  of  his  left  thigh  pressing  against 


645 


the  arm  of  the  chair,  his  right  foot  thrown  a 
little  forward,  and  his  trunk  inclined  a  little 
backward  and  to  his  left.  The  alveolus,  as 
always,  is  hrnily  grasped  between  the  finger  and 
thumb  of  the  left  hand,  with  the  other  fingers 
under  the  jaw  (see  Fig.  881).  He  considers  that 
in  this  position  the  operation  can  be  performed 
in  a  more  gainly  and  workmanlike  manner,  and 
he  has  never  been  able  to  follow  the  reasoning 
of  Tomes  and  Nowell  \\ho,  speakmg  of  it,  say  : 
"  This  is  indeed  a  disadvantageous  position, 
it  is  difficult  to  see  where  the  blades  of  the 
forceps  are,  and  the  operator  is  encumbered  by 


i'^ 


his  own  body  being  between  the  operating  hand 
and  the  patient's  mouth." 

He  has  never  experienced  any  difficulty  in 
seeing  the  whereabouts  of  the  blades  of  the 
forceps,  or  even  demonstrating  it  to  a  class,  and 
he  has  never  succeeded  in  so  contorting  his  body 
as  to  bring  it  into  that  undesirable  position 
between  his  hand  and  the  patient's  mouth. 
Consequently,  he  must  decluie  to  admit  the 
cogency  of  the  objections  stated.  He  does  not 
dispute  the  fact  that  many  experienced  and 
skilful  operators  work  "across",  standing  on 
the  right  front,  but  he  cannot  imagine  tliat  their 
reasons  for  preferring  this  stance  are  those  above 
quoted. 

Conduct  of  the  Left  Hand. — The  generalj'prin- 
ciple  on  wliich    this  may  be  founded  is  :   that 


Fig.  880. 


Fig.  SSI. 


646 


Fig.  882. 


in  any  and  every  case  the  alveolar  border  at 
the  point  where  the  forceps  are  to  be  apphed 
should  be  firmly  grasped  between  the  fore- 
finger and  thumb  of  the  left  hand.  Taking  first 
the  anterior  maxillary  teeth,  the  forefinger  on 
the  labial  side  carries  away  the  lip,  keeping 
it  out  of  harm's  way,  and  by  firm  pressure 
supports  the  outer  table,  preventing  its  fracture 
or  excessive  displacement,  while  the  parts  are 
grasped  and  controlled  by  the  opponent  thumb 
on  the  lingual  aspect.  The  thumb  is  kept 
slightly  bent,  thus  affording  a  shelf  or  inclined 
plane,  which   directs   teeth   that   "jump",   or 


Fic.  88:1. 


Fig.  884. 

slip,  forwards  out  of  the  mouth  into  safety  and 
bars  tlieir  passage  towards  the  floor  of  the 
mouth  or  the  j)harynx  (see  Fig.  882). 

For  right  mandibular  cheek  teeth,  the  fore- 
finger and  thumb  must  be  passed  well  into  the 
mouth ;  the  forefinger  should  carry  away,  and 
keep  away,  the  cheek,  while  the  thumb  keeps 
the  tongue  out  of  the  way  and  guards  against 
injury  of  that  organ.  The  other  fingers  pass 
under  the  jaw,  support  it  against  the  downward 
pressure  of  the  forceps,  and  steady  it  during  the 
extraction  (see  Fig.  883).  For  left  mandibular 
cheek  teeth  the  roles  of  forefinger  and  thumb  are 
exchanged  (see  Fig.  884). 

For  right  maxillary  cheek  teeth,  the  wrist  is 
bent  and  the  elbow  raised,  the  thumb  is  on  the 
buccal  side  and  holds  away  the  cheek,  and  the 


QVi 


I'Ui.  885. 


forefinger  is  on  the  lingual  side  (see  Fig.  885). 
For  left  maxillary  cheek  teeth,  wrist  and  hand 
are  nearly  horizontal ;  the  forefinger  is  on  the 
buccal,  the  thuml)  on  the  lingual,  side  (see 
Fig.  886). 

\^^aen  the  finger  and  thumb  are  introduced 
into  the  mouth,  they  should  be  carried  well  back 
first,  and  then  opened  out  to  grasp  the  alveolar 
margins  at  the  point  desired.  With  an  ex- 
perienced operator  these  movements  become 
automatic,  so  too  do  the  adjustments  whereby 
he  keeps  away  the  tongue  and  cheek  by  a  slight 
bending  of  the  phalangeal  joints.  The  educated 
touch  and  muscular  sense  of  the  finger  and 
thumb    greatly    assist    him    in    the    accurate 


Fig.  88(). 


Fig.  887. 

adaptation  of  the  forceps,  and  also  apprise  him 
of  the  strength  of  the  resistance  encountered 
and  of  the  moment  of  yielding,  and  enable  him 
to  restrain  haemorrhage  and  at  once  to  compress 
the  margins  of  the  alveolus  when  the  extraction 
is  completed. 

5.  Introduction  and  Application  of  the  Forceps 

The  method  of  taking  up,  opening,  and  hold- 
ing the  forceps  is  shown  in  the  illustrations  (see 
Figs.  887,  888).  The  butt  of  the  loft  handle 
should  lie  in  the  centre  of  the  palm  of  the  hand, 
and  from  this  position  it  should  never  shift  or 
slip,  as  on  its  maintenance  depends  the  steady 
application  of  the  driving  power  and  pressure, 
which  persists  during  the  operation.  As  is  the 
case  with  almost  every  tool  in  the  hand  of  a 
skilled  worker,  the  long  axis  of  the  instrument 
crosses  the  hand  at  an  angle  and  in  such   a 


648 


position  that  when  grasped  for  use  the  thumb 
comes  to  lie  along  it.  The  forceps  held  as  shown 
are  introduced  into  the  mouth  for  application  to 
the  tooth.  In  the  case  of  the  upper  cheek  teeth 
the  blades  of  the  forceps  should  always  be 
entered  in  a  plane  parallel  to  the  occlusal 
surfaces  of  the  tooth,  and  so  carried  to  the  tooth 
to  be  extracted,  when  a  slight  depression  of 
the  hand  enables  one  instantly  and  correctly 
to  apply  them.  For  the  anterior  teeth  above 
and  below,  the  blades  are  presented  in  a  plane 
parallel  to  the  long  axes  of  the  teeth. 

The  lower  forceps  are  picked  up,  grasped,  and 
applied  in  an  exactly  similar  maimer ;  the 
blades,  which,  be  it  remembered,  are  at  right 
angles  to  the  handles  instead  of  in  a  straight  or 
curved  line  with  them,  are  for  cheek  teeth 
carried  to  the  back  of  the  mouth  in  the  hori- 
zontal   position,   or    parallel    to    the    occlusal 


Fig.  S88. 

surfaces,  when  a  turn  of  the  wrist  brings  them 
into  line  with  the  roots  of  the  teeth  to  \\hich 
they  are  to  be  applied. 

To  open  the  forceps  to  the  required  extent, 
the  end  of  the  little  finger  is  used  to  move  away 
the  butt  of  the  right  handle,  the  left  handle 
being  now  gripped  by  the  thumb  and  fore- 
finger, while  the  outward  movement  of  the 
right  handle,  and  consequently  the  opening  of 
the  left  blade,  is  controlled  liy  the  second  and 
third  fingers  on  the  outside  of  the  right  handle. 
The  fleshy  part  of  the  thumb  may  with  advan- 
tage lie  between  the  handles,  the  upper  edge 
of  the  right  handle  impinging  on  the  point  of 
the  thumb  at  its  side  and  on  its  palmar  aspect. 

The  forceps  being  introduced,  opened,  and 
applied,  the  operator  firmly  grips  the  handles 
and  drives  the  blades  well  home  along  the  root 
or  roots,  beyond  the  neck.  He  must  remember 
to  keep  the  butt  of  the  left  handle  in  the  middle 
of  the  palm  of  his  hand.  If  he  does  not  he  will 
find  his  hand  sHpping  up  the  handles  till  he  is 
grasping  them  near  the  joint  instead  of  near 
their  ends,  when  he  will  be  depriving  himself 


of  every  mechanical  advantage  the  instrument 
is  designed  to  afford  him.  He  can  neither  drive 
them  home  with  the  same  nice  calculation, 
efficiency,  and  strength,  nor  exercise  his  ex- 
tractive force  with  such  precision,  delicacy  of 
direction,  and  power,  as  he  can  when  he  grips 
the  handles  near  their  distal  extremity,  and 
constitutes  them  an  extension  of  his  hand  and 
forearm  by  holding  them  as  described,  with  the 
butt  of  the  left  handle  in  the  palm  of  the  hand 
right  in  front  of  the  middle  of  the  carpus.  The 
forceps  should  be  driven  home  "  in  once ", 
without  ineffectual  prods.  In  the  case  of 
conical  roots  this  driving  home  of  the  blades 
often  evicts  them  at  once,  the  blades  acting  as 
a  pair  of  wedges,  and  the  principle  involved 
being  the  well-known  one  that  two  (or  in  this 
case  three)  bodies  cannot  occupy  the  same  space 
at  the  same  time.  But  as  a  rule  some  extractive 
force  has  to  be  appUed. 

6.  Extraction 

A  knowledge  of  the  anatomy  of  the  teeth  and 
associated  parts  is  essential.  It  must  be 
remembered  that  :  (a)  the  buccal  surfaces  of 
the  teeth  are  disposed  on  the  circumference  of  a 
larger  arch  than  that  on  which  the  lingual 
surfaces  lie,  or,  in  other  words,  the  teeth  are 
rouglily  wedge-shaped ;  (6)  the  alveolus  (except 
of  the  third  lower  molar)  is  thinner  and  more 
easily  displaced  on  the  buccal  than  on  the 
lingual  side ;  (c)  the  roots  of  upper  incisors  and 
canines  are  conical ;  {d)  the  roots  of  lower 
incisors  and  canines  are  conical,  and  flattened 
very  much  laterally ;  (e)  separate  roots  of 
cheek  teeth  are  conical ;  (/)  roots  of  lower  cheek 
teeth,  when  they  curve,  curve  distajly  ;  {g)  the 
medio -buccal  root  of  a  maxillary  molar  is  larger 
than  the  disto-buccal  root,  and  the  lingual  or 
palatine  root  lies  m  most  cases  behind  the  middle 
of  the  tooth. 

Extraction  with  forceps  comprises  (a)  adapta- 
tion to  the  tooth  or  root ;  (b)  solution  of  con- 
tinuity between  the  tooth  or  root  and  the 
socket ;  (c)  removal  of  the  tooth  or  root  from 
the  socket  and  the  mouth. 

The  instruments  and  methods  most  in  vogue 
in  this  country  will  be  described  as  they  are 
applicable  to  individual  teeth. 

Upper  Incisors. — Straight  forceps  (as  shown 
in  Fig.  889)  are  advised.  The  inner  blade  is 
applied  first,  then  the  outer.  The  blades  are 
diiv'en  forcibly  past  and  under  the  edge  of  the 
alveolus,  and  as  far  as  may  be  along  the  root. 
While  strong  upward  pressure  is  maintamed,  a 
firm  hold  of  the  handles  is  taken,  and  tooth, 
forceps,  hand,  wrist,  and  arm,  become,  as  it 
were,  one  long  rod  with  a  conical  termination. 
This  conical  end  is  fixed  in  a  more  or  less  dense 
medium  by  accurate  or  tight  implantation ;  it 
is  also  secured  by  Sharpey's  fibres,  which  cross 


649 


from  alveolus  to  cenientiiin  in  a  direction 
transverse  to  its  length.  It  is  obvious  that  a 
very  slight  degree  of  rotation  of  the  root  will 
sever  all  these  fibres,  since  they  are  hardly,  if  at 
all,  extensile.    It  is  equally  obvious  that  a  little 


Fig.  889.  —  Forceps  for 
Upper  Incisors,  Canines, 
and  First  Premolars. 

{Messrs.  Claudius  Ash, 
Sons,  d-  Co.,  Lid.) 


-  Forceps    for 
Upper       Pre- 


FiG.    890, 

Second 

molars. 
(Messrs.     Claudius     Ash 

Sons  &  Co.,  Ltd.) 


outward  movement  of  the  distal  extremity  of 
the  rod  or  lever  will  slightly  displace  outwards 
the  thin  outer  wall  of  the  bony  socket  at  its 
free  margin,  thus  enlarging  the  aperture  of 
emergence.  At  the  same  time  the  point  of 
the  cone  will  move  downwards  and  inwards, 
and  if  unimpeded  its  track  would  lie  along  a 
curve.  But  it  impinges  on  the  dense  un- 
yielding inner  wall,  and  as  the  result  of  the 
principle  set  forth  in  the  proposition  known  as 
the  parallelogram  of  forces,  is  impelled  do\\n- 
wards.  The  operator,  therefore,  rotates,  hold- 
ing the  forceps  firmly,  but  refraining  from  a 
crushing  stress,  and  rotating  the  tooth  from  him, 
because  his  supinator  muscles  are  so  much  more 
powerful  and  better  trained  than  his  pronators. 
Simple  rotation,  combined  with  the  ^Acdge-like 
action  of  the  blades,  oftens  suffices,  but  if  it  is 
insufficient  it  is  supplemented  by  a  steady 
outward  movement. 

Upper  Canines. — The  same  instrument  and 
the  same  method  are  employed,  but  rotation 
is  not  always  so  useful,  because  the  root  more 
often  departs  from  the  circular  conical  form. 
It  may  be  flattened  or  curved,  and  it  is  usually 
21* 


longer  and  stronger  tlian  the  incisor  roots,  and 
hence  offers  more  resistance. 

First  Upper  Premolars. — The  same  forceps 
are  used.  The  tooth  is  usually  two-rooted,  and 
flattened  medio -distally;  the  roots  may  be 
confluent.  The  inner  blade  is  applied  first. 
The  blades  must  lie  driven  well  home ;  then 
forcep-handles,  hand,  wrist,  arm,  and  shoulder, 
are  carried  steadily  outwards. 

Second  Upper  Premolars. — The  root  is  usually 
single,  but  may  be  bifurcated ;  it  is  not  so 
much  flattened  as  that  of  the  first  premolar. 
The  forceps  must  be  a  curved  pair  (see  Fig.  890), 
in  order  that  they  may  be  more  easily  intro- 
duced, applied,  and  used,  and  that  without 
injuring  the  lips  or  lower  teeth.  The  extraction 
is  carried  out  in  the  same  way  as  for  the  first 
premolar. 

Upper  Molars. — These  teeth  have  normally 
three  roots,  two  buccal  and  one  lingual.  Of  the 
two  buccal  roots  the  medio-buccal  is  the  larger, 
and  the  disto-buccal  lies  on  a  plane  slightly 
internal  to  the  medio-buccal.  The  Imgual  root 
is  the  largest  of  the  three,  and  diverges  from  the 
crown  at  a  greater  angle  than  the  other  two  ;  it 
lies  in  a  plane  distal  to  the  medio-buccal  root, 


Fig.  891.  —  Forceps  for 
Right  Upper  Molars. 

(Messrs.  Claudius  Ash, 
Sons  <fc  Co.,  Ltd.) 


Fic.  892.  —  Forceps  for 
Left  Upper  Molars. 

(Messrs.  Claiulius  Ash, 
Sons  tSc  Co.,  Ltd.) 


and  opposite  to  the  disto-buccal  root  and  a 
small  portion  of  the  crown  anterior  to  it.  It  is 
important  to  remember  this  because  if  the 
blades  of  the  forceps  are  applied  exactly  opposite 
to  each  other,  the  inner  blade  will  miss  the 
lingual    root;     the    inner   blade    must    always 


650 


therefore  lie  a  little  behind  the  outer.  Forceps 
specially  designed  for  extracting  upper  molars 
have  the  outer  blade  pointed  or  lieaked  between 
two  grooves  of  which  the  medial  is  the  broader, 
with  the  distal  smaller  and  on  a  slightly  interior 
plane  (see  Figs.  891,  892).  The  lingual  blade 
has  no  point  and  embraces  the  lingual  root  at 
the  neck  of  the  tooth.  The  blades  are  bent  at 
an  angle  to  tlie  handles  to  facilitate  introduction 
and  enable  the  handles  to  clear  the  hps ;  the 
handles  themselves  are  curved,  so  that  when 
pressure  is  made  at  the  butts  it  is  transmitted 
without  loss  of  power  in  a  line  to  the  blades.  A 
pair  of  these  forceps  « ill  be  required  for  either 
side,  right  and  left.  The  position  of  the  lingual 
root  being  remembered,  the  inner  blade  is  applied 
first,  and  the  outer  blade  then  adapted  so  that 
the  point  or  beak  lies  in  the  space  between  the 
two  buccal  roots.  The  handles  are  now  carried 
outwards,  firm  upward  pressure  being 
at  the  same  time  maintained. 

The  third  upper  molar  may  be  as 
large  as  the  first  or  second,  and  have 
its  roots  similarly  disposed,  when  the 
same  forceps  may  be  used  for  its 
removal.  But  very  often  it  is  smaller, 
and  has  its  roots  more  or  less  com- 
pletely confluent.  It  lies  usually  above 
and  behind  the  second  molar,  and  is  to 
that  extent  more  inaccessible.  A  pair 
of  forceps  having  a  greater  curvature, 
and  with  both  blades  similar  to  the 
lingual  blade  of  the  upper  molar-forceps, 
will  then  be  found  more  efficient.  Great 
care  must  be  taken  not  to  include  any  of  the 
soft  tissues  or  alveolus  between  the  blades,  lest 
the  gum  be  torn  or  the  tuberosity  fractured. 

Upper  Molar  Roots. — \Vlien  the  crown  of  an 
upper  molar  is  much  broken  dowia  and  carious 
beyond  the  gum  level,  root-forceps  should  be 
used.  Generally  speaking,  the  inner  blade 
should  be  apphed  first  to  the  lingual  root,  then 
the  outer  blade  to  the  medio-buccal  root. 
Wlien  a  firm  hold  is  assured,  the  forceps  should 
be  strongly  driven  upwards,  while  the  handles 
are  carried  outwards.  Strong  support  of  the 
alveolar  walls  between  the  finger  and  thumb  of 
the  left  hand  is  especially  essential.  It  may  be 
impossible  to  dislodge  the  tooth  owing  to  one 
of  the  blades  slipping,  though  this  rarely  happens 
to  an  experienced  operator ;  if  the  lingual  blade 
pulls  or  slips  off  owuig  to  the  lingual  root  being 
carious  and  frail  for  most  of  its  length,  the 
outward  movement  may  be  departed  from  and 
inward  movement  of  the  handles  tried.  Some- 
times extraction  may  be  rendered  easy  by  first 
separating  the  roots ;  this  may  be  done  by 
placing  the  outer  blade  between  the  buccal  roots 
and  the  imier  blade  to  the  medial  side  of  the 
lingual  root,  and  strongly  compressing  the 
handles.     Often   all    three   roots   are   loosened 


by  this  manoeuvre ;  one  or  more  may  even  be 
dislodged,  and  in  any  case  all  three  may  be 
readily  jjicked  out  separately. 

When  three  roots  are  present  but  separate, 
exhibituig  no  cohesion,  they  are  easily  extracted 
Extraction  is  effected  by  slight  rotation.  The 
operator  should  make  a  point  of  taking  them  in 
a  definite  order  of  succession  thus  :  (a)  medio- 
buccal,  (6)  di^to-buccal,  (c)  lingual.  He  will 
thus  make  sure  of  removing  all  three,  and  will 
spare  himself  the  chagrin  attendant  upon  the 
return  of  the  patient  complaining  that  a  root 
has  been  left  in.  It  is  interesting  to  note  that 
if  a  root  is  missed  it  is  nearly  always  the  medio- 
buccal,  less  frequently  though  occasionally  the 
lingual,  seldom  the  disto-buccal. 

Loiver  hicisors. — The  forceps  shown  in  Fig. 
893  are  used ;  the  blades  are  of  equal  size. 
The    lingual    blade    should    be    adjusted    first 


Fig.  893.- 


-Forceps  for  Lower  Incisors,  Canines,  Premolars,  and 
Molar  Roots. 
(Messrs.  Claudius  Ash,  Sons  d;  Co.,  Ltd.) 

and  then  the  laliial.  The  blades  should  slip 
past  the  neck  of  the  tooth  as  they  are 
pressed  home,  the  mandible  being  firmly 
supported  the  while.  By  depression  of  the 
handles  of  the  forceps,  brought  about  by  the 
lowering  of  the  elbow  while  the  \\Tist  and  hand 
are  kept  fairly  rigid,  the  extractive  force  is 
applied  maiidy  in  the  outward  direction,  but  it 
must  be  borne  in  mind  that  the  blades  tend  to 
rise  as  the  handles  go  down,  so  that  the  resulting 
force  is  also  somewhat  upwards.  Very  little 
force  is  as  a  rule  required  to  extract  these  teeth 
with  their  laterally  flattened  conical  roots ;  care 
must  be  taken  not  to  lacerate  the  gum  or  break 
away  the  alveolus. 

Lower  Canines. — -The  same  forceps  serve,  and 
the  same  procedure,  but  the  tooth  being  longer 
and  stronger,  the  extractive  force  has  commonly 
to  be  proportionately  increased. 

Loiver  Premolar.s. — These  rank  as  cheek  teeth, 
and  the  stance  of  the  operator  will  be  behind 
the  patient  for  right  lower  premolars,  while  for 
left  lower  premolars  he  will  stand  on  the  patient's 
right  or  left  front  according  to  his  training  and 
predilections.  The  same  forceps  are  used.  The 
lingual  blade  is  apphed  first.  The  jaw  must 
be    staunchly    supported,    and    the    extractive 


651 


force  applied  by  depressing  the  elbow.  The 
blades  must  be  kept  pressing  downwards  all 
the  time.  As  the  root  is  conical,  rotation  may 
be  employed  as  an  adjuvant  extractive  force 
by  imparting  a  slight  backward  swing  to  the 
handles  as  they  are  carried  downwards. 

Lower  Molars  (First  and  Second). — ^The 
hawk's-bill  molar-forceps  (see  Fig.  894)  are  those 
generally  advised.  The  blades  are  beaked,  with 
a  groove  on  either  side  of  the  beak  ;  the  grooves 
being  equal  in  size,  one  pair  suffices  for  both  sides 
of  the  jaw.  The  operator  adopts  the  stance 
and  grip  of  the  jaw  with  the  left  hand  that  he 
prefers.  The  inner  blade  must  be  applied  first, 
and  the  best  methods  of  introduction  and 
application  of  the  forceps  must  be  carefully 
studied  and  acquired  till  they  become  almost 
automatic  actions.  It  is  very  important  that 
the  blades  should  be  pressed  well  home ;  that 
the  jaw  should  be  very  firmly  supported,  or 
even  pressed  up  against  the  downward  pressure 


Flu.  894. — Forceps  for  Lower  Molars. 

(Messrs.  Claudius  Ash,  Sons  cfc  Co., 

of  the  forceps;  that  the  eye  should  never  be 
taken  off  the  tooth  ;  that  all  violence,  jerkiness 
and  sudden  wrenching,  should  be  avoided  ;  and 
that  the  forceps  should  be  applied  in  the  same 
line  with,  not  obliquely  to.  the  long  axis  of  the 
tooth,  and  so  that  the  handles  point  rather 
upwards.  The  extractive  force  is  exerted  by 
carrying  the  elbow  downwards  (the  wrist  should 
be  hardly  at  all  bent) ;  the  handles  of  the  forceps 
may  at  the  same  time  be  carried  slightly  back- 
wards. As  the  resultant  the  tooth  is  moved 
outwards,  upwards  and  forwards — the  direction 
of  least  resistance.  If  the  crown  of  the  tooth 
is  too  far  gone  to  permit  the  use  of  these  forceps, 
the  hawk's-bill  root-forceps  are  used  in  similar 
fashion.  The  stronger,  less  carious  root  should 
be  grasped ;  the  other  one  often  comes  with  it, 
but  if  it  does  not,  is  taken  separately,  or  ejected 
with  the  elevator. 

Sometimes  the  crown  of  a  lower  molar  is 
tUted  so  far  inwards  as  to  give  rise  to  difficulty 
in  adjusting  hawk's-bill  forceps ;  in  such  cases 
the  straight  forceps  may  be  used. 

Third  Lower  Molars. — Either  hawk's-biU  or 
straight  forceps  may  be  used.  A  close  bite 
with  a  narrow  gape  may  preclude  the  use  of  the 


hawk's-bill  or  even  of  the  straight  instrument, 
and  extraction  then  demands  the  employment 
of  the  elevator.  Li  extracting  the  second  and 
third  lower  molars  it  is  generally  advised  that 
the  tooth  should  be  moved  mainly  in  the  inw  ard 
direction,  because  the  labial  alveolus  thickens 
in  their  situation.  This  is  an  argument  in 
favour  of  the  use  of  the  straight  forceps,  as 
much  movement  in  the  inward  direction  is 
incompatible  with  the  u.se  of  the  hawk's-bill, 
because  only  a  very  limited  upward  excursion 
of  the  handles  of  that  instrument  is  possible. 
But  the  extractive  force  required  is  mainly  in 
the  upward  and  forward  direction  (that  of  the 
long  axis  of  the  tooth  produced),  and  this  is 
applied  with  the  hawk's-bill  by  the  course 
recommended  of  carrying  the  handles  down- 
wards and  slightly  back\\ards,  and  refraining 
from  any  outward  pull  or  wrench,  but  rather 
indeed  keeping  up  an  inward  push  during  the 
process. 

The  gum  often  has  a  strong  adhesion 
to  the  distal  side  of  the  neck  of  the  third 
lower  molar,  and  may  easily  be  stripped 
and  come  away  with  the  tooth  if  care  is 
not  exercised.  A  skilful  extractor  will 
avoid  this  accident.  He  should  pause 
as  soon  as  he  perceives  it  to  be  imminent, 
and  by  now  firmly  holding  down  the  gum, 
wliile  a  slight  twist  is  given  to  the 
loosened  tooth,  separation  may  be 
effected ;  if  it  is  not,  the  gum  must  be 
separated  with  lancet  or  scissors  before 
the  removal  of  the  tooth  is  completed. 
Deciduous  Teeth. — These  are  extracted 
in  a  similar  way,  but  with  smaller  instruments. 
Precaution  must  be  observed  in  pressmg  down 
the  blades,  which  must  not  pass  too  far  along 
the  roots,  lest  the  successional  tooth  be  dis- 
turbed, injured,  or  even  removed,  along  with 
its  predecessor.  The  roots  of  deciduous  molars 
diverge  at  a  considerable  angle  from  the  neck, 
so  as  to  aiiord  room  for  the  crypts  of  the 
premolars,  and  the  extraction  of  these  teeth 
is  attended  with  acute  pain. 

The  reader  will  probably  have  noticed  that 
in  the  foregoing  description  of  the  extraction 
operation  as  applicable  to  the  diff'erent  teeth, 
the  writer  has  followed  fairly  closely,  save  in 
one  particular,  the  directions  sanctioned  by 
general  usage  and  invested  with  the  authority 
of  the  text-books.  The  particular  exception 
is  the  direction  always  given  to  precede  the 
outward  movement  by  a  slight  inward  move- 
ment. His  reason  is  that  for  normally  formed, 
placed,  and  implanted  teeth  he  believes  this 
preliminary  inward  movement  to  be  useless  and 
superfluous ;  it  adds  a  pang  to  an  ordinary 
extraction,  and  wastes  precious  time  in  an 
extraction  under  an  anaesthetic.  He  nmst  ad- 
mit that  the  weight  of  authority  and  tradition 


Ltd. 


652 


is  against  him  on  this  particular  point,  as  all  the 
authors  he  has  consulted  advise  the  preliminary 
inward  movement.  Nevertheless,  he  is  con- 
vinced as  the  result  of  long  and  abundant 
experience  that  the  force  should  be  applied 
first  by  carrying  the  handles  outwards  for  upper 
teeth,"  downwards  for  lower  teeth.  In  nearly 
every  case  extraction  will  be  effected  with  ease. 
Should,  however,  unusual  resistance  appear, 
then  the  direction  of  the  force  may  with 
advantage  be  varied,  till  the  factor  preventing 
extraction,  generally  an  abnormal  development 
or  curvature  of  the  root  or  roots,  is  overcome, 
and  the  tooth  loosened. 

Writer's  Methods 
The  writer  himself  uses  but  two  pairs  of  forceps, 
one  for  the  maxillary  teeth,  one  for  the  mandi- 
bular.    The    forceps   illustrated  (see  Fig.  895) 


Fig.  895. — Lower  and  Upper  Forceps  (writer's  pattern). 

are  similar  in  design  to  the  ordinary  upper  root- 
forceps  and  hawk's-bUl  root-forceps.  But  the 
blades  are  rather  stouter  in  make  and  a  trifle 
longer ;  the  curve  of  the  blades  in  the  uppers  is 
a  little  more  decided,  and  in  the  lowers  they 
are  more  bowed,  so  as  to  include  the  crown  of 
a  molar.  The  points  of  the  blades  are  rather 
broader ;  they  must  meet  when  closed  and  must 
come  to  a  knife-edge.  The  workmen  who  make 
forceps  appear  to  have  an  annoying  habit  of 
filing  flat  the  insides  of  the  blades,  thus  con- 
verting them  into  flat  pliers  rather  than  forceps. 


The  writer  has  taught  students  to  use  these 
forceps  for  many  years,  and  although  he  is 
quite  prepared  to  be  told  that  they  are  in- 
sufficient to  meet  all  emergencies,  the  fact 
remains  that  for  the  past  eighteen  years  he  has 
never  had  occasion  to  resort  to  any  others, 
either  in  his  practice  at  the  Edinburgh  Royal 
Infirmary  and  Edinburgh  Dental  Hospital,  or 
in  private. 

The  principles  specially  involved  in  the  use 
of  these  forceps  may  be  summarized. 

In  every  extraction,  if  the  roots  (or  root)  are 
extracted  the  crown  must  come  as  well ;  it  is 
possible  to  break  away  the  crown  and  leave  the 
root,  but  not  to  take  the  root  and  leave  the 
crown.  Therefore  in  every  case  it  seems  rea- 
sonable to  attack  the  root  and  disregard  the 
crown.  Probably  most  operators  \\ill  be  ready 
to  concede  that  these  forceps  are  adequate  to 
the  extraction  of  incisors,  canines,  and  pre- 
molars, so  that  the  battle  of  the  forceps  may 
be  waged  around  tlie  molars.  Smale  and  Colyer 
(11)  make  the  following  statement:  "In  all 
cases  where  there  is  danger  of  a  molar  fracturing, 
root-forceps,  in  preference  to  ordinary  forceps, 
should  be  used."  The  writer  is  almost  pre- 
pared to  rest  his  case  on  this  admission ;  he 
merely  goes  a  little  farther  in  propounding  the 
proposition  that  in  all  cases  root-forceps  should 
be  used.  There  is  always  a  danger  of  a  tooth 
fracturing,  especially  when  it  is  grasped  by  the 
neck ;  the  danger  is  perhaps  greater  with  molar 
forceps,  and,  happening  with  them,  the  accident 
necessitates  a  change  to  root-forceps,  whereas 
if  it  happens  with  root-forceps  it  is  as  likely  as 
not  to  make  the  extraction  easier  rather  than 
more  difficult. 

Molar-forceps  are  in  truth,  only  suitable  for 
teeth  that  are  not  badly  broken  down,  and  in 
which  there  is  strong  union  between  crown 
and  roots  at  the  neck — for  teeth,  in  short,  most 
of  which  could  be  fUled  or  crowned. 

Furthermore,  molar-forceps  camiot  be  driven 
along  the  roots  as  root-forceps  can,  and  the 
extraordinary  loosening  and  ejective  force 
exercised  by  the  blades  acting  as  a  pair  of 
wedges  is  lost. 

In  using  these  root-forceps  certain  points, 
even  at  the  expense  of  reiteration,  mu.st  be  in- 
sisted on.  In  every  case  the  alveolus  must  be 
grasjjed  between  the  finger  and  thumb  of  the 
left  hand.  The  successful  and  skilful  use  of 
the  left  hand  is  of  an  importance  that  can  hardly 
be  exaggerated.  Tlie  finger  and  thumb  can  be 
so  educated  as  to  keep  away  the  tongue  and 
cheek,  support  and  compress  the  part  operated 
on,  check  and  control  haemorrhage,  prevent 
laceration  or  fracture,  depress  the  base  of  the 
tongue  if,  arrested  half\\ay  in  a  swallowing 
movement,  it  blocks  the  faucial  aperture  of  the 
respiratory  passage,  direct  the  blades  of  the 


653 


forceps,  prevent  the  passage  of  a  tooth  or  root 
in  any  other  direction  than  out  of  the  mouth, 
locate  a  buried  or  obscured  root,  tilt  the  jaw  to 
the  most  advantageous  position,  communicate 
to  the  operator  the  amount  of  alveolar  resistance 
or  movement,  and  protect  surrounding  parts 
from  injury.  In  comparison  with  the  command 
of  the  lo«er  jaw  obtained  by  grasping  it  with 
the  finger  and  thumb  and  supporting  it  with 
the  other  fingers,  the  control  that  can  be  got 
by  placing  the  first  two  fingers  one  on  each  side 
with  the  thumb  underneath,  is  decidedly  feeble. 

In  applying  the  blades  of  the  forceps  to  an 
upper  molar,  the  inner  blade  is  driven  up  the 
lingual  root,  the  outer  blade  up  the  medio- 
buccal  root.  The  reader  should  apply  the 
forceps  to  a  few  molar  teeth  out  of  the  mouth, 
to  convince  himself  of  the  firm  hold  thus 
obtained.  Li  appljdng  the  root-forceps  to  a 
lower  molar,  it  is  essential  to  remember  that 
they  are  root-forceps,  and  are  to  be  used  as 
such ;  that  is  to  say,  that  the  blades  are  to  be 
applied  to  one  root  or  the  other — not  to  the 
space  between.  Nearly  all  beginners  display 
an  instinctive  tendency  to  apply  them  to  the 
middle  of  the  tooth.  The  blades  should  be, 
when  introduced,  almost  horizontal,  with  the 
points  directed  backwards  till  the  tooth  is 
reached,  when  a  turn  of  the  wrist  brings  them 
into  position  for  driving  home. 

Mechanics  of  Extraction  with  Forceps.  —  It 
will  now  be  well  to  recapitulate  the  condi- 
tions of  the  problem  at  the  moment  of  extrac- 
tion, as  they  have  been  already  stated.     Tooth, 


Fig.   896. — Diagram  of  section  tlirough  Upper  Tooth 

and  Alveolus. 
AA,  Inner  and  outer  Alveolus ;  G,  Gum ;  N,  Free  edge 
of  gum ;  P,  Periodontal  Membrane  ;  D,  Dentine ; 
E,  Enamel ;  C,  P,  Pulp  cavity. 

(Pye^s  Surgical  Handicrajt. ) 

forceps,  hand,  wrist,  and  arm  constitute  a 
long  lever;  the  conical,  bifid  or  trifid  end  of 
this  lever  is  implanted  in  bone,  from  which 
environment  the  operator  desires  to  extricate  it. 
The  figure  (Fig.  896)  (1,  p.  439)  shows  a  section 


through  an  upper  single  conical-rooted  tooth 

and  alveolus  ;  the  next  figure  (Fig.  897)  shows  the 

same  tooth  with  the  forceps  ajjplied.     Now  the 

application  of  the  forceps  means  the  driving 

of  two  curved  wedges  up  the  sides  of  the  cone 

with  displacement  of  the 

alveolar      border,      very 

slight  on  the  inner  side, 

more    extensive    on    the 

outer  side.     In  fact,  the 

driving  in  of  the  wedge 

on  the  inner  side  results 

in    displacement    of    the 

tooth,      and     the     outer 

alveolus  with  it,  outwards, 

rather  than  in  movement 

of     the     imier     alveolus 

inwards. 

The   handles    are    now 

compressed.  The  jjressure 

of  the  blades,  which  fit 

the  smooth   sides  of  the 

conical    root,    will    often 

cause    the    projection    of 

the  tooth,    the   resultant 

force  in  the  direction  of 

long    axis    of    the    tooth 

making  the  conical  root 

slip  downwards  between 

the    blades.     A    familiar  -pia.  897. 

analogue  is  the  projection 

of  an  orange -pip  between  the  finger  and  thumb. 

Commonly,  ho^\•ever,  the  tooth  requires  some- 
thing more.  Simple  rotation  severs  its  connec- 
tion with  the  socket,  and  a  slight  outward 
movement  of  the  handles  brings  it  away. 

Now  as  Norman  G.  Bennett  (1,  p.  439) 
observes,  "  this  outward  movement  is  in  the 
case  of  most  teeth  the  chief  movement  that 
separates  the  tooth  from  the  bone."  Consider 
carefully,  therefore,  the  mechanics  of  the  pro- 
cess at  this  stage. 

Presented  in  diagrammatic  form  and  in  section 
(see  Fig.  898),  T  is  the  conical  end  of  the  lever 
embedded  in  the  socket.  lA  is  the  inner  alveo- 
lus, OA  the  outer  alveolus,  now  shghtly  displaced 
outwards ;  the  po«er  is  applied  at  H,  the  distal 
end  of  the  lever,  in  the  direction  indicated  by 
the  dotted  line  HP.  Note  that  the  power  not 
only  carries  the  distal  end  of  H,  the  lever,  out- 
wards, but  also  along  a  curve,  successive  pomts 
of  which  lie  at  increasing  distances  from  the 
point  of  implantation,  so  that  there  comes  to 
be  a  drag  away  as  weU  as  an  outward  move- 
ment. The  point  F,  the  margm  of  the  outer 
alveolus,  becomes  the  fulcrum  of  the  lever; 
hence  again  mark  the  importance  of  supporting 
the  outer  wall  of  the  alveolus,  for  if  it  bo  broken 
away  the  fulcrum  is  lost.  The  power  applied 
at  H  causes  T  to  impinge  with  great  pressure 
on  lA  in  the  downward  and  inward  direction ; 


654 


lA  is,  however,  unyielding,  the  inward  force 
is  cancelled  by  the  resistance  of  lA — the  result- 
ant force  is  do«  nwards,  i.  e.  T  slips  down  along 
lA — ,  T  begins  to  emerge,  and  as  it  does  so, 
owing  both  to  the  do\\nward  passage  of  T  and 
the  excursion  of  H,  the  fulcrum  at  F  lies  at 
an  ever-dimuiishing  distance  from  T,  so  that 
the  effective  power  is  an  increasing  one  from 
the  moment  that  the  motion  of  T  begins. 
This  passage  outwards  and  downwards  of  the 
now  moving  implanted  end  of  the  lever  over 
the  fulcrum,  is  greatly  assisted  by  the  smooth 
rounded  character  of  the  blade  of  the  forceps, 
which  constitutes  the  part  of  the  lever  in  contact 
with  the  fulcrum.  As  T  passes  do\^•n^^•ards  and 
H  outwards,  there  may  be  some  further  out- 
ward displacement  of  OA  ;  this  serves  to  enlarge 
the  aperture  of  emergence.     The  dotted  outline. 


P^iG.  898. 

T\  shows  the  position  that  T  must  occupy 
when  H  is  carried  to  H'. 

If  the  reader  cares  to  perform  a  little  experi- 
ment, illustrative  of  this  proposition,  let  him 
take  about  an  inch  of  the  sharpened  end  of  a 
pencil  between  the  fuiger  and  thumb  of  his  left 
hand.  The  sharp  end  of  the  pencil  represents 
T,  the  forefuiger  OA,  the  thumb  lA.  Let 
him  now  carry  outwards  the  other  end  of  the 
pencil,  using  the  pulp  of  the  forefinger  as  the 
fulcrum,  keeping  the  stronger  thumb  immovable, 
but  allowing  the  weaker  forefinger  to  be  slightly 
displaced,  and  he  will  see  the  point  of  the  pencil 
pass  down  the  pulp  of  his  thumb  till  the  pencil 
is  extricated  from  his  grasp.  With  the  same 
apparatus  he  may  demonstrate  the  futility 
of  pulling  the  lever,  as  opposed  to  outward 
movement. 

The  proposition  as  stated  requires  but  little 


modification  to  be  appUcable  to  upper  molars. 
It  only  need  be  remembered  that  the  two 
buccal  roots  are  pressed  inwards  through  or 
with  the  softer  porous  bone  of  the  septa,  and 
that  attention  may  be  fixed  on  the  lingual  root, 
to  reconstitute  the  jiroblem  and  arrive  at  the 
same  solution.  For  mandibular  teeth  the 
reasoning  is  readily  followed,  if  it  be  premised 
that  the  conical  or  bifid  end  of  the  lever  is 
in  their  case  lient  almost  at  a  right  angle  with 
its  length. 

Extraction  with  Elevators. — For  description  of 
instruments,  see  p.  642. 

It  may  be  conceded  that  there  is  scarcely  a 
root  or  even  a  tooth  that  camiot  be  removed  by 
the  elevator  (1,  p.  575).  But  the  more  dexter- 
ous and  confident  an  operator  becomes  in  the 
use  of  the  forceps,  the  less  often  will  he  find 
himself  employing  an  elevator.  So  far  as  the 
maxillary  teeth  are  concerned,  the  elevator  is 
hardly  ever  (if  ever)  needed,  and  the  use  of 
this  instrument  is  practically  restricted  to  the 
dislodgement  of  mandibidar  cheek  teeth  or 
roots. 

In  using  the  straight  elevator,  the  handle 
is  held  firmly  in  the  palm  of  the  hand,  and 
the  forefinger  lies  along  the  blade,  the  point 
of  which  should  not  be  more  than  three- 
quarters  of  an  inch  from  the  tip  of  the  fore- 
finger. The  flat  side  of  the  blade  presents 
to  the  tooth  to  be  extracted.  The  sharp  end 
of  the  blade  is  driven  down  along  the  medial 
surface  of  the  root  as  far  as  possible.  The  handle 
is  now  depressed  with  a  slight  rotatory  move- 
ment in  the  opposite  direction  to  that  in  which 
the  tooth  is  expected  to  emerge.  The  sharp 
end  should  bite  into  the  cementum  of  the  root. 
The  elevator  acts  as  a  lever,  the  fulcrum  being 
provided  by  the  neck  or  crown  of  the  tooth 
to  the  medial  side  of  that  being  operated  on, 
or  by  the  gum  and  alveolus,  supplemented, 
perhaps,  by  the  fuiger  or  thumb  of  the  operator's 
left  hand.  As  the  handle  is  depressed  the  tooth 
will  be  tilted  backwards.  It  may  be  necessary, 
\\  hen  a  certain  amount  of  movement  is  obtained, 
to  shift  the  sharp  end  of  the  elevator  to  a  point 
lower  do\TO  the  root,  so  as  to  retain  the 
mechanical  advantage  afforded  by  the  instru- 
ment, and  again  depress  and  rotate ;  indeed, 
this  manceuvre  may  have  to  be  repeated  more 
than  once.  The  tooth  is  often  completely 
ejected  in  this  way,  but  quite  frequently  the 
operator,  having  loosened  and  partly  dislodged 
it  with  the  straight  elevator,  finishes  the  ex- 
traction with  forceps. 

The  general  practice  nowadays  seems  to  be 
to  reserve  the  straight  elevator  for  third  lower 
molars.  It  is  a  dangerous  weapon  in  the  hand 
of  the  inexpert ;  consequently,  the  surrounding 
parts  must  be  always  carefully  guarded  by  the 
left   hand.     The   force   required   is   sometimes 


655 


considerable,  and  should  the  point  slip  it  may 
be  driven  into  the  tongue,  cheek,  palate,  floor 
of  the  mouth,  tonsU,  or  pharynx.  The  internal 
carotid  artery  lies  very  near  and  might  easily 
be  wounded.  The  writer  never  employs  a 
straight  elevator,  save  for  the  purpose  of  de- 
monstrating its  use  to  students  ;  for  he  believes 
that  all  it  can  effect  can  be  achieved  with  a 
curved  elevator,  which  is  more  under  the  control 
of  the  operator,  is  easier  to  introduce,  is  safer 
to  handle,  and  is  worked  far  more  by  steady 
rotation  of  the  handle  than  by  its  forcible 
depression. 

A  pair  of  curved  elevators  will  be  required 
for  the  right  and  left  sides  of  the  jaw,  and  also 
according  as  the  blade  is  applied  to  the  medial 
or  distal  surface  of  the  root.  For  the  third 
lower  molar  it  is  applied  usually  to  the  medial 
surface ;  for  the  other  mandibular  teeth  it  will 
be  found  better  to  apply  it  to  the  distal  side  as 
a  rule,  because  the  roots  curve  backwards,  and 
so  wUl  be  more  easily  ejected  by  the  application 
of  a  force  that  drives  them  out  in  the  direction 
corresponding  to  the  outward  extension  of  the 
line  of  their  implantation.  It  is  surprising  to 
observe  with  what  facility  a  series  of  separate 
mandibular  roots  can  be  removed  with  a  curved 
elevator  starting  at  the  most  distal  and  working 
forwards. 

For  the  right  side  the  operator  stands  behind  ; 
the  thumb  of  his  left  hand  is  on  the  lingual 
side  of  the  jaw  and  the  forefinger  on  the  buccal, 
the  other  fingers  supporting  the  jaw.  For  the 
left  side  the  writer  strongly  advises  the  stance 
on  the  left  side,  with  the  finger  of  the  left  hand 
on  the  Imgual  and  the  thumb  on  the  buccal 
side  of  the  jaw.  Many  operators,  however, 
stand  on  the  right  front,  and  use  the  first  two 
fingers  of  the  left  hand  to  hold  the  jaw,  but 
this  position  and  grasp  involve  a  loss  of  power 
and  control.  In  turning  out  a  root  or  tooth 
with  the  curved  elevator,  the  blade  is  driven 
down  along  the  distal  side  of  the  root.  The  root 
if  not  very  fii-mly  attached  may  at  once  rise  in 
the  socket,  because  two  bodies  camiot  occupy 
the  same  space  at  the  same  time ;  but  if  it  does 
not,  and  presuming  that  the  blade  is  applied  to 
the  distal  surface,  the  handle  is  rotated  towards 
the  back  of  the  mouth,  and  at  the  same  time 
slightly  depressed.  This  causes  the  working 
surface,  i.  e.  the  point  of  the  blade,  to  move 
upwards  and  forwards,  and  the  root  is  impelled 
in  the  same  direction,  which  is  that  of  least 
resistance.  The  result  being  mainly  attained 
by  rotation  of  the  handle,  the  principle  of  the 
lever  is  applied,  as  in  that  modification  of  the 
simple  lever  known  as  the  wheel  and  axle  (9). 

\\1iile  generallj'  preference  is  to  be  given  to 
the  method  of  using  the  curved  elevator  from 
behind  forwards,  as  described,  it  may  often 
be  used  with  advantage  from  before  backwards. 


as,  for  example,  when  a  single  root  lies  close  to 
the  distal  side  of  a  standing  tooth.  Those  who 
stand  on  the  right  front  and  operate  across, 
often  prefer  to  apply  the  blade  to  the  medial 
side  of  the  root.  The  rotation  of  the  handle 
must,  if  the  blade  is  applied  to  the  medial 
side  of  the  root,  be  towards  the  front  of  the 
mouth. 

DIFFICULTIES    OF    EXTRACTION 

Cases  regarded  as  difficidt  will  bo  in  inverse 
ratio  to  the  skill  and  experience  of  the  operator  ; 
nevertheless,  difficulties  from  time  to  time  pre- 
sent themselves  even  to  the  most  skilful.  They 
depend  on — 

(1)  Abnormalities  of  the  tooth  in  regard 
to  position,  size,  union  or  gemination  \\'ith 
other  teeth,  dilaceration,  size  of  roots,  shape 
and  disposition  of  roots,  excessive  number  of 
roots,   hyperplasia   of   cementum   or  exostosis. 

(2)  Abnormahties  of  the  bone  or  joint. 

(3)  Abnormalities  of  the  soft  parts. 

(1)  Abnormalities  of  the  Tooth. — With  respect 
to  irregularly  placed  teeth,  either  within  or 
without  the  arch,  the  blades  of  the  forceps 
must  be  applied  to  the  root  in  the  most  ad- 
vantageous position  offered  by  the  particular 
tooth,  and  the  extractive  force  must  be  applied 
in  such  a  way  as  neither  to  fracture  the  alveolus, 
nor  loosen  adjacent  teeth.  A  common  instance 
is  the  upper  canine  high  up  and  outside  the 
arch — the  "buck-tooth".  The  blades  are  ap- 
plied to  the  medial  and  distal  sides  of  the  root, 
and  extraction  is  effected  by  rotation  and  out- 
ward movement.  To  attempt  to  grasp  this  root 
by  the  lingual  and  labial  aspects  would  result 
in  the  displacement  or  fracture  of  the  lateral 
incisor.  Similarly,  a  maxillary  central,  lateral, 
or  supernumerary  inside  the  arch,  is  to  be 
seized  medially  and  distally.  Root -forceps  with 
speciaOy  narrow  blades  wiU  sometimes  be 
found  useful  for  these  cases. 

The  malposition  most  often  attended  with 
serious  difficulty  is  that  of  the  third  mandibular 
molar  unerupted  or  partially  erupted,  and  Ijing 
more  or  less  horizontally,  impacted  against  the 
second  molar,  and  having  its  roots  embedded  in 
dense  bone  beneath  the  base  of  the  coronoid 
process.  If  the  tooth  is  partly  erapted  the  soft 
parts  may  be  pressed  aside  by  packing  till  a 
clear  view  of  the  crown  is  obtained.  Many  such 
teeth  can  be  grasped  and  extracted  by  forceps, 
but  the  curved  elevator  is  often  the  appropriate 
instrument.  In  some  cases  it  may  be  necessary 
to  cut  away  some  bone  to  expose  the  situation 
of  the  tooth,  and  a  radiograph  may  prove  of 
value.  One  hears  and  reads  of  desperate 
struggles  to  extract  these  teeth,  lasting  from 
half    an  hour   to   an  hour  and  a   half    under 


656 


general  anaesthesia,  and  one  feels  bound  to 
suggest  that  such  cases  should  be  referred  to 
a  recognized  expert  in  extraction. 

The  illustrations  (see  Figs.  899-905)   depict 
some  of  the  abnormalities  in  form  that  may 


extracting  many  apparently  impossible  teeth, 
but  it  must  not  be  forgotten  that  separation  of 
the  roots  often  enables  them  to  be  removed 


Fig.  Stin. 

cause  difficulty  in  extraction.  The  difficulty 
appreciated  is  that  of  excessive  resistance  to  the 
extractive  force,  the  tooth  refusing  to  budge 
when  the  force  is  applied  in  the  ordinary  way 
and  degree.     Caution  is  imperative.     The  direc- 


FiG.  900. 

tion  of  the  force  must  be  varied  till  that  direction 
is  found  in  which  it  promises  to  overcome  the 
resistance,  and  the  force  must  be  carefully 
increased  in  proportion  to  the  resistance  en- 
countered.   The  tactus  eruditus  will  succeed  in 


Fig.  901. 

with  ease  and  expedition,  when  their  extrac- 
tion en  masse  with  the  tooth  is  a  manifest 
impossibility. 


Fig.  902. 

(2)  Abnormalities  of  the   Bone   or  Joint. — The 

commonest  is  an  excessive  degree  of  con- 
solidation of  a  thick 
strong  alveolus,  more 
frequently  met  with 
in  isolated  teeth  that 
have  lost  their  neigh- 
bours. Should  such  a 
firmly  implanted  tooth 
defy  extractive  effort, 
it  is  well  to  desist,  and 
try  it  again  in  a  day  or 
two,  when,  loosened 
by  periodontitis,  it 
may  be  removed  with 
comparative  ease. 
Neoplasms  of  the 
maxilla  or  mandible 
may  give  rise  to  difficulty ; 
the  administration  of  an 


Fig.  903. 

trismus  may  demand 
anaesthetic  and  the 


657 


forcible  opeiiing  of  the  mouth ;  and  immobihty 
of  the  mandibular  joint  from  progressive  in- 
flammatory changes  or  complete  anchylosis  may 
be  encountered,  when  tlie  aid  of  the  surgeon 
must  be  requisitioned. 

(3)  Abnormalities  of    the    Soft   Parts. — A  very 
small  mouth  with  a  very  narrow  gape,  so  that 


there  is  little  separation  of  the  occlusal  surfaces 
of  the  cheek  teeth  when  the  mouth  is  fully 
opened,  may  import  some  difficulty.  Extreme 
sensitivity  of  the  tongue  and  palate,  the  emesis 
reflex  being  excited  whenever  an  instrument  or 
the  finger  is  introduced  into  the  mouth,  may  be 


Fjg.  !)U5. 

overcome  by  spraying  with  an  atomizer  con- 
taining a  1  per  cent  solution  of  hydrochloride  of 
cocaine.  Spongy  gums  may  give  trouble  by 
bleeding  profusely,  hypertrophied  gums  bj' 
obscuring  teeth  or  roots  buried  in  their  depths. 
Extensive  infiltration,  swelling,  and  brawniness, 
may  attend  sepsis.     Immobility  of  the  jaw  may 


be  present  as  the  result  of  cicatricial  contrac- 
tion of  the  soft  tissues  of  the  cheek  and  gum 
consequent  on  cancrum  oris  or  post-exanthe- 
matous  gangrene.  Adjacent  neoplasms  may 
also  affect  the  mobility  of  the  mandible. 

ACCIDENTS   OF   EXTRACTION 

Fracture  of  the  Tooth.— This  is  more  liable 
to  happen  when  the  tooth  is  gripped  by  the 
crown  or  neck  instead  of  bj'  the  root ;  when 
the  force  is  applied  suddenly  or  jerkily ;  when 
the  forceps  are  not  kept  well  pressed  home  ;  or 
when  the  lingual  blade  slips,  or  more  likely 
is  pulled  off.  When  a  tooth  is  broken  the 
root  or  roots  should  be  extracted  at  once ;  if 
this  proves  difficult  the  attempt  should  be 
abandoned,  to  be  repeated  in  a  few  days  when 
the  roots  will  be  loosened  by  the  attendant 
inflammation.  If  the  fracture  exposes  the 
pulp,  and  the  patient  is  to  be  dismissed  with 
the  roots  still  in,  the  pulp  should  first  be  de- 
sensitized by  the  application  of  pure  carbolic 
acid  or  cocaine,  and  then  removed.  Should 
the  part  broken  off  be  no  more  than  the  apical 
portion  of  a  root,  it  is  better  to  leave  it  than 
to  make  prolonged  efforts  to  extricate  it,  but 
the  patient  should  always  be  told  that  a  small 
piece  has  broken  in,  which  will  probably  come 
away  in  due  time. 

Extraction  of  the  Wrong  Tooth. — This  is  an 
avoidable  accident,  and  should  be  regarded  as 
an  exhibition  of  culpable  carelessness  rather 
than  an  accident.  Replantation  should  be 
fierformed. 

Fracture  of  the  Alveolus. — If  only  a  small 
piece  of  bone  is  removed,  no  serious  consequences 
need  ensue ;  care  should  be  taken  not  to  court 
this  accident  by  inclucUng  the  alveolus  between 
the  blades  of  the  forceps.  WTiile  the  fracture 
and  detachment  of  large  sections  of  bono  are 
generally  due  to  the  use  of  unsuitable  forceps, 
then  incorrect  application,  and  the  injudicious 
use  of  excessive  and  misdirected  force,  yet 
instances  occur  in  which  large  pieces  of  bone 
are  detached  though  every  care  is  taken.  The 
tuberosity  of  the  maxilla  sometimes  comes 
away  \vith  the  third  upper  molar,  and  many 
instances  of  extensive  alveolar  fracture  are 
reported  in  the  text-books  and  journals.  The 
floor  of  the  maxillary  sinus  may  be  broken  and 
a  tooth  or  root  driven  into  it ;  if  this  hap- 
pens an  attempt  should  be  made  to  wash  it 
out  again  by  syringing,  or  to  recover  it  by 
sr£are  or  suitable  dressing-forceps  if  syringing 
fails.  In  the  last  resort  the  opening  should  be 
enlarged,  or  a  fresh  opening  made  through  the 
buccal  wall  large  enough  to  permit  of  the  re- 
covery of  the  root  or  tooth.  Cases  of  fracture 
of  the  mandible  during  extraction  are  not 
unknown. 


658 


Dislocation  of  tiie  Mandible. — This  may  liap- 
pen  from  the  too  extensive  opening  of  the 
mouth  by  a  screw-gag,  or  from  neglecting  to 
support  the  jaw  during  the  extraction  of  lower 
teeth ;  or  it  may  be  unavoidable,  as  there  are 
individuals  in  \\hom  the  condyle  shps  forward 
very  easily.  The  dislocation  is  not  a  serious 
matter  uiiJess  it  escapes  the  dentist's  observa- 
tion; it  should  be  reduced  at  once.  G.  H. 
Bowden  (2)  records  a  case  of  deafness  following 
bilateral  dislocation  of  the  mandiljle  during 
extraction  ;  but  how  this  untoward  result  came 
to  pass  is  by  no  means  clear. 

Two  Teeth  may  be  Extracted  Instead  of  One. 
The  elevator  may  dislodge  a  tooth  used  as  a 
fulcrum.  Occasionally  a  premolar  may  be 
brought  away  along  with  a  deciduous  molar. 

Laceration  of  the  Gum.- — A  good  operator  will 
seldom  tear  the  gum  if  he  uses  sharp-bladed 
forceps  and  applies  them  properly.  But  some- 
times the  gum  adlieres  strongly  to  the  neck  of 
the  tooth,  and  may  be  torn  or  stripped  from 
the  bone  as  the  tooth  is  extracted.  The  operator 
should  be  on  the  look-out  for  this  contingency, 
and  may  sometimes  prevent  it  by  fii-mly  holding 
down  the  gum  as  he  removes  the  tooth ;  if, 
however,  the  gum  does  not  at  once  part  from 
the  tooth,  it  should  be  separated  by  scalpel  or 
scissors. 

Tearing  the  Inferior  Alveolar  Nerve. — This  occurs 
when  the  roots  of  a  mandibular  molar  are 
in  such  relation  to  the  inferior  alveolar  canal 
as  to  embrace  the  trunk  of  the  nerve,  which  is 
lacerated  or  divided  when  the  tooth  is  extracted. 
There  is  paralysis  of  sensation  in  the  parts 
supplied.  Reunion,  however,  generally  takes 
place,  and  restoration  of  function  follows  in  a 
few  months'  time.  Vorslund-Kjaer  reports  a 
case  (14)  in  which  permanent  insensibility 
followed  this  accident,  which  was  accompanied 
at  the  time  by  enormous  haemorrhage  and 
unbearable  pain. 

One  Tooth  may  be  broken  while  another  is 
being  extracted. — A  lower  tooth  may  happen  to 
come  out  w  ith  unexpected  ease  ;  if  the  operator 
is  applying  the  force  too  nmch  in  the  upward 
direction — trj-ing  to  pull  up  the  tooth — his 
forceps  fly  up  against  and  may  break  a  maxillary 
tooth.  The  pressure  of  an  elevator  may  break 
a  fulcrum  tooth. 

The  Lips  may  be  bruised  or  split. — This  may 
occur  by  their  being  pressed  against  the  lower 
incisors  by  the  handles  of  the  forceps  during 
the  extraction  of  upper  teeth.  Suitably  curved 
forceps  ensure  avoidance  of  this  accident. 
The  tongue,  or  even  the  inner  surface  of  the 
cheek,  may  be  included  in  the  forceps  and 
cut  or  torn,  and  the  same  parts  may  be 
wounded  by  the  slipping  of  an  elevator.  It 
may  bo  necessary  to  take  surgical  measures 
to  arrest  bleeding  from    a    wounded   tongue ; 


the  insertion  of  a  suture  may  suffice,  or  it 
may  be  necessary  to  expose  and  twist  the 
bleeding  vessel ;  cauterization  may  be  tried  if 
this  fails,  and  failing  all  else,  ligature  of  the 
lingual  artery.  Much  pain  and  discomfort 
attend  a  laceration  of  the  tongue,  and  anti- 
septic precautions  should  be  observed  while  it 
is  healing. 

The  Forceps  or  the  Elevator  may  break. 
Endelman  (5)  includes  in  a  list  of  casualties 
collected  by  him  a  case  in  which  a  broken  piece 
of  forceps  was  left  in  the  jaw  after  extraction, 
with  subsequent  septic  infection. 

A  Tooth  may  be  broken  or  dislocated  by  a  Gag 
or  Mouth-opener. 

Less  Frequent  Accidents. — A  tooth  or  root, 
or  pieces  thereof,  a  broken  piece  of  forceps, 
a  filling,  a  crown,  a  gag  or  portion  of  a 
gag,  or  even  a  sponge  or  swab,  may  pass 
into  the  respiratory  tract,  or  be  swallowed. 
A  blood-clot  may  block  the  isthmus  of  the 
fauces ;  blood,  pus,  or  oral  fluids,  may  pass 
into  the  trachea  or  oesophagus.  In  some 
patients  ecchymoses  result  from  even  gentle 
handling  of  the  parts,  and  quite  extensive 
bruising  may  follow  the  necessary  pressure  and 
manipulation  accompanving  the  extraction 
operation.  Cases  are  met  with  (7)  in  which 
more  or  less  extensive  extravasation  into  the 
tissues  has  followed  extraction. 

SEQUELAE  OF  EXTRACTION 

Post-extraction  Pain. — This  may  be  due  to 
causes  existing  before  the  operation,  such  as 
periostitis,  alveolar  abscess,  neuritis,  neuralgia, 
or  necrosis ;  or  to  causes  incidental  to  the 
operation,  such  as  displacement  or  injury  of 
the  alveolus,  or  of  the  gum,  or  injury  either  to 
the  main  trunk  or  terminal  filaments  of  nerves. 
Too  rapid  closure  of  the  external  aperture  of 
the  wound  may  cause  pain  by  retention  of 
discharges.  Post-extractional  sepsis  and  sup- 
puration are  often  very  painful  conditions. 

The  treatment  of  post-extraction  pain  must 
1)0  on  general  principles  according  to  the  cause. 
If  by  any  chance  the  pain  is  due  to  a  piece  of 
tooth  being  left  in,  either  it  must  be  taken  out, 
or  the  exposed  portion  of  pulp  must  be  anaes- 
thetized and  removed.  If  the  socket  has  closed 
too  rapidly  it  must  be  opened  up  to  allow  it  to 
heal  from  the  bottom,  swabbed  out,  syringed 
with  warm  antiseptic  solution,  and  kept  open 
for  a  while.  As  precautionary  measures  against 
post-extraction  pain,  attention  to  pressing  in 
the  alveolar  wall  by  the  finger  and  thumb  of  the 
left  hand  at  the  moment  of  extraction  is  im- 
portant, and  the  routine  use  of  an  antiseptic 
mouth-wash  after  operation,  such  as  the  phenol 
sodique  used  warm,  should  never  be  neglected. 
The  patient  should  be  told  to  hold  the  mouth- 


659 


wash  in  the  mouth  for  a  minute  at  a  time  hy 
the  watch  if  it  is  to  do  any  good. 

Neuroma  has  been  suggested  as  a  possible 
cause  of  pain.  Removal  of  opposing  teeth 
sometimes  allo^\s  the  bite  to  close,  so  that  some 
of  the  remaining  teeth  bite  on  the  freshly 
wounded  alveolus,  causing  pain  and  delaying 
healing.  It  is  comforting  to  know  that  pain 
after  extraction  seldom  needs  other  treatment 
than  fomentation  of  the  wound  with  hot  anti- 
septic solution.  If  the  pain  prevents  the 
patients  sleeping,  the  dentist  should  not  pre- 
scribe a  narcotic,  the  administration  of  such 
agents  being  l>est  left  to  the  medical  attendant. 

Post-extraction  Haemorrhage. — In  patients  who 
are  haemoijliiliacs  the  risk  of  haemorrhage  is  a 
somewhat  serious  consideration.  It  will  not 
be  wise  to  extract  more  than  one  tooth  at  a 
time  for  such  patients.  A  haemophiliac  should 
be  put  on  a  preliminary  course  of  treatment  of 
chloride  or  lactate  of  calcium,  grs.  x  to  xv, 
thrice  daily  for  a  week  previous  to  operation. 
The  extraction  should  bo  done  in  the  morning, 
and  the  patient  kept  under  observation  for  the 
re.st  of  the  day.  If  the  tooth  is  one  with  a 
single  circular  conical  root,  an  india-rubber 
band,  made  by  snipping  off  about  jV  i'l-  from 
the  end  of  a  piece  of  small  drainage-tube,  may 
be  sUpped  on  to  the  neck  of  the  tooth  and 
allowed  to  work  its  way  up  the  root.  Peri- 
odontitis accompanies  this  procedure,  which  is 
not  without  pain  and  discomfort,  but  the  tooth 
becomes  so  loose  that  it  may  be  removed  with 
much  diminished  risk  of  bleeding.  In  all  cases 
of  know  n  or  suspected  haemopliilia  it  is  probably 
good  practice  to  plug  the  socket  at  once,  whether 
haemorrhage  occurs  or  not.  Wright  states 
that  the  inhalation  of  CO.,  for  a  few  seconds  will 
always  check  the  bleeding  in  haemophilia. 

Ordinary  alveolar  haemorrhage  may  be  : 
(1)  Primary,  which  occurs  at  the  time  of  extrac- 
tion;  (2)  Reactionary  or  Intermediate,  coming 
on  some  hours  afterwards,  often  during  the 
night ;  and  (3)  Tnie  Secondary  Haemorrhage, 
which  is  the  result  of  ulceration  or  sloughing 
of  the  walls  of  the  vessels,  does  not  occur  till 
a  week  or  ten  days  after  the  operation,  is  always 
of  most  serious  import,  and  is  certainly  of 
extreme  rarity  after  tooth  extraction. 

In  both  primary  and  reactionary  haemorrhage 
the  treatment  will  be  to  endeavour  to  control 
the  bleeding  by  the  application  of  very  hot  or 
very  cold  water,  or  by  the  use  of  various  stj'ptics 
or  haemostatics,  and  if  these  fail  to  arrest  it  by 
direct  pressure.  This  direct  pressure  is  usually 
exercised  by  means  of  an  alveolar  plug,  which 
may  be  supplemented  either  by  one  or  more 
sutures  passed  through  the  gum  from  side  to 
side  and  tied  on  the  surface,  or  by  an  inter- 
dental pad  of  gutta-percha  or  cork  held  in  place 
by  opijosing  teeth,  the  mandible  being  secured 


and  pressure  kept  up  by  a  four-taUed  bandage. 
Very  hot  water  should  always  be  tried  first. 
The  patient  should  not  be  allowed  to  spit  out 
violently,  but  rather  should  the  water  and 
blood  trickle  or  flow  from  tlie  mouth.  Many 
styptics  and  haemostatics  have  been  used. 
Clot  and  debris  should  be  removed,  the  socket 
dried  as  quickly  as  possible,  and  the  chosen  re- 
agent carried  in  on  lint,  cotton- wool,  or  gauze. 
Perchloride  of  iron  should  never  be  used ;  it 
is  dirty  and  messy  and  causes  sloughing,  and, 
moreover,  the  clot  that  it  produces  to  block  the 
lumen  of  the  vessels  is  soluble  in  scrum,  .so  that 
the  haemorrhage  is  likely  to  recur. 

Tannic  acid,  adrenalin  chloride,  alum,  and 
turpentine,  are  perhaps  the  standard  haemo- 
statics for  dentists.  Hamamelis  (witch-hazel, 
hazeline)  is  sometimes  used.  Tomes  and  Nowell 
extol  the  virtue  of  matico-leaf.  As  a  general 
rule  it  is  not  sufficient  to  apply  a  haemostatic 
without  plugging,  if  the  haemorrhage  is  of  any 
importance. 

The  writer  uses  a  plug  of  cotton-wool,  which 
is  first  wTung  out  of  an  alcoholic  solution  of 
perchloride  of  mercury  (1  in  1000),  then  dipped 
in  thick  mastic  varnish,  and  finally  rolled  in 
powdered  alum  till  it  has  a  good  coating  of  the 
salt.  This  plug  is  forced  well  home  with 
vaseUned  instruments;  an  elevator  is  an 
excellent  tool  for  this  purpose.  The  alum  is 
the  coagulant,  while  the  resin  of  the  varnish, 
being  precipitated  from  its  alcoholic  solution, 
makes  the  plug  quite  firm  and  soUd.  This 
treatment  in  the  writer's  hands  has  been  uni- 
formly successful.  The  plug  should  be  removed 
when  it  becomes  loose  by  itself. 

Gauze,  adrenalin,  and  tamun,  make  an 
effective  plug  as  advised  by  Norman  G.  Bennett 
(1,  p.  448).  Walter  Pye  (10)  speaks  very  highly 
of  a  metliod  suggested  by  Sir  A.  E.  Wright, 
which  consists  in  filHng  the  socket  with  formaha 
and  gelatin.  Commercial  gelatin  will  not  do 
as  it  often  contains  the  spores  of  bacillus  tetani ; 
the  gelatin  used  must  be  bacteriologically 
sterile.     The  procedure  given  is  as  follows — 

"  Place  a  test-tube  containing  the  gelatin 
in  a  bowl  of  water  sufficiently  warm  to  melt 
the  gelatin.  Care  must  be  taken  that  the  water 
is  not  too  hot,  for,  if  overheated,  gelatin  loses 
its  power  of  solidifying  when  cooled.  When  the 
contents  of  the  tube  are  fairly  fluid  add  to  them 
.■V  part  of  pure  formalin,  i.  e.  if  the  test-tube 
contains  40  c.cm.  gelatin,  add  2  c.cm.  formalin. 
Shake  the  tube  so  that  the  two  mix.  Now 
with  the  patient's  mouth  wide  open,  sponge 
away  the  blood  with  gauze  or  wool  pledgets 
until  the  socket  is  fairly  dry,  and  then,  soaking 
a  thin  strip  of  gauze  in  the  mixture  in  the  test- 
tube,  press  it  well  home  to  the  bottom  of  the 
cavity.     Keep  it  thus  for  one  or  two  minutes, 


660 


withdraw  it,  and  pour  in  the  mixture  of  gelatin 
and  formalin,  which  is  now  nearly  solid.  A 
little  care  ^\^ll  enable  the  operator  to  fill  the 
whole  socket  with^this_valuable  styptic,  which 
soon  solidifies." 

As  an  adjuvant  to  plugging,  gallic  acid  may 
be  administered  internally  in  15-grain  doses  re- 
peated every  two  or  three  hours  for  twelve  hours. 
The  patient  should  be  kept  sitting  up,  or  propped 
up  in  bed  with  the  head  cool  and  the  feet  warm, 
and  fed  on  cold  liquids.  The  extracted  tooth 
has  often  been  used  as  a  i)lug ;  if  this  is  done 
it  should  at  least  be  well  washed  before  being 
put  back. 

If  the  measures  recounted  fail,  surgical 
assistance  must  be  invoked ;  it  may  be  neces- 
sary to  plug  the  inferior  alveolar  or  palatine 
canal,  or  even  to  tie  the  carotid.  Wliere  the 
loss  of  blood  has  been  excessive,  and  the  patient 
is  in  a  state  of  syncope,  restorative  measures 
must  be  taken  promptly ;  it  may  even  happen 
that  transfusion,  or  infusion  of  normal  saline 
solution,  may  afford  the  only  chance  of  saving 
the  patient. 

Sepsis  following  Extraction. — In  dealing  with 
this  subject  one  is  confronted  by  the  apparent 
anomaly  that  while  it  is  impossible  to  maintain 
the  field  of  operation  in  a  sterile  condition,  yet 
there  is  no  area  of  the  body  more  tolerant  of  in- 
jury, or  in  which  a  septic  condition  so  rarely  leads 
to  systemic  infection.  Nevertheless,  the  dentist 
is  culpable  who  neglects  to  endeavour  by  the 
judicious  use  of  antiseptics  before  and  after 
operation,  and  by  rigid  adherence  to  aseptic 
technique,  to  minimize  the  risk  of  local  sepsis, 
or  general  infection  from  the  wound.  The  pre- 
cautions advised  on  pp.  641  and  642  must  be 
always  taken,  and  an  antiseptic  mouth-wash 
before  and  after  extraction  should  form  part 
of  the  ritual.  The  wound  should  bo  inspected 
from  time  to  time.  Whatever  mouth-wash  is 
chosen,  the  patient  should  be  directed  to  hold 
it  in  the  mouth  for  a  minute  at  a  time,  not 
violently  swilling  it  round,  but  merely  allowing 
it  to  lave  the  wound ;  and  then  to  let  it  gently 
flow  or  trickle  out  of  the  mouth  ^\ithout  ener- 
getic suction  or  expectoration.  It  is  well  to 
wash  out  the  mouth  after  every  meal,  to  prevent 
particles  of  food  lodging  or  decomposing  in 
the  wound ;  cold  or  tepid  water — or  better  still 
water  sterilized  by  boiling — may  be  used  for  this 
purpose,  followed  by  the  mouth- wash.  This 
should  bo  done  five  times  a  day  till  healing  is 
complete. 

Although  the  tissues  exhibit  wonderful  re- 
cuperative power,  and  healing  is  usually  un- 
eventful, yet,  as  the  result  of  trauma  and  sepsis, 
one  must  be  prepared  to  meet  and  deal  \\ith 
excessive  inflammation,  suppuration,  ulceration, 
osteitis,  osteo-myelitis,  or  necrosis. 


The  so-called  "dry  socket ",  in  which  the 
alveolar  margins  of  bone  are  exposed,  bare, 
inflamed,  and  sensitive,  is  generally  due  to 
disturbance  and  septic  liquefaction  of  the  clot 
(often  caused  by  injudicious  packing  of  the 
socket),  followed  by  inflammation  of  the  de- 
nuded bony  surface.  Careful  cleansing  and 
stimulation  to  a  healthy  reaction  by  the  use  of 
such  remedies  as  orthoform,  or  touching  with 
trichloracetic  acid,  supplemented  by  curetting 
of  granulation  tissue,  is  the  appropriate  treat- 
ment. If  the  exposed  edge  has  undergone 
superficial  necrosis  it  wiU  be  non-sensitive,  and 
may  be  curetted  or  burred  away  as  recom- 
mended by  0.  E.  Inglis  (6).  The  same  author 
uses  nitric  acid  to  dissolve  the  dead  bone  and 
promote  granulation.  In  the  writer's  experi- 
ence, if  necrosis  has  taken  place,  antisepsis  and 
the  expectant  line  of  treatment,  \vith  removal 
of  the  necrosed  bone  when  it  separates,  are 
indicated.  Sloughs  must  be  removed,  abscesses 
evacuated,  and  sinuses  washed  out.  For  pack- 
ing sinuses  or  abscess  cavities,  either  a  bismuth 
sub-nitrate  and  vaseline  paste,  or  a  paste  of 
orthoform,  zinc  oxide,  and  vaseline  has  been 
recommended 

Where  necrosis  causes  the  death  of  any  con- 
siderable portion  of  alveolar  bone,  precipitation 
in  its  removal  is  to  be  deprecated ;  the  seques- 
trum should  not  be  removed  until  it  has 
separated.  General  experience  confirms  the 
conclusion  long  since  arrived  at  by  the  writer, 
that  cases  of  excessive  inflammation,  sloughing, 
and  necrosis,  are  much  commoner  after  extrac- 
tions when  a  local  anaesthetic  has  been  injected  : 
the  paralj'sis,  impaired  vitality,  and  arrested 
circulation,  sufficiently  explain  this  result. 

Suppuration  of  the  socket  calls  for  surgical 
cleaidiness  and  antisepsis.  The  socket  should 
l>e  gently  syringed  out  with  hydrogen  dioxide 
(10  vols.) ;  it  may  be  dried  and  touched  with 
zinc  chloride  or  trichloracetic  acid,  and  anti- 
septic lavage  thereafter  assiduously  practised. 
Should  the  floor  of  a  lower  molar  socket  be  in 
close  relation  to  the  inferior  alveolar  canal,  care 
must  be  taken  not  to  implicate  the  mandilnilar 
nerve  in  the  application  of  escharotics  or  curet- 
tage. While  general  infections  are  admittedly 
rare,  they  do  occur  from  time  to  time.  Whether 
in  respect  of  the  operation  they  are  post  hoc  or 
propter  hoc,  it  must  often  be  difficult  to  deter- 
mine. Septicaemia,  pyaemia,  sapraemia,  septic 
thrombosis,  metastatic  abscesses,  septic  and 
embolic  pneumonia,  glossitis,  tonsillitis,  pharyn- 
gitis, gangrene,  meningitis,  phlebitis,  and  tetanus, 
are  not  only  possible  sequelae  of  the  extraction 
operation,  but  stand  recorded  as  having  occurred. 
Their  treatment  is  not  for  the  dentist. 

The  most  dreaded  infection  of  all,  perhaps,  is 
syphilis,  and  the  importance  of  the  dentist 
being  acquainted  with  and  ready  to  recognize 


661 


the  manifestations  of  this  disease  cannot  be 
urged  too  insistently.  Ignorance  or  carelessness 
may  result  either  in  the  infection  of  one  patient 
from  another,  or  in  the  inoculation  of  the 
operator  himself. 

Surgical  Shock. — That  a  certain  degree  of 
surgical  shock  attends  the  extraction  operation, 
should  never  be  forgotten.  It  must  be  regarded 
as  contra-indicating  extensive  extractions  in 
frail  weak  subjects. 

Syncope  or  fainting  sometimes  happens. 
The  chair  should  be  tilted  back  so  that  the 
patient's  head  is  lower  than  his  trunk  and 
extremities,  smelling-salts  or  ammonia  should 
be  held  to  the  nose,  and  restoratives — brandy 
or  twenty  drops  of  sal  volatile  in  water — 
adHiinistered.  If  syncope  is  profound  and  pro- 
longed, medical  aid  should  be  summoned.  For 
faintness  the  patient  should  be  directed  to  bend 
forward,  bringing  the  head  between  the  knees 
or  lower,  so  as  to  facilitate  the  flow  of  blood  to 
the  brain. 

Mania. — Dentists  should  be  alive  to  the  danger 
of  transitory  deferred  mania  consequent  on  the 
exhibition  of  cocaine  as  an  analgesic.  The 
writer  recalls  a  case  in  which  the  patient,  a 
big,  strong  farmer,  ^^■as  referred  to  him  by  a 
surgeon  who  had  for  diagnostic  purj)Oses  cocain- 
ized the  nasal  passages  by  spraying.  The 
patient  sat  down  in  the  chair  to  have  his  teeth 
examined,  but  before  anything  was  done 
suddenly  rose  and  savagely  attacked  the  nurse 
who  accompanied  him,  and,  had  he  not  been 
forcibly  restrained,  might  have  killed  or  seriously 
injured  her.  In  another  case  that  was  brought 
to  his  notice,  the  driver  of  a  char-;x-banc  who 
had  had  a  tooth  removed  ^nth  cocaine  injected 
locally  in  the  morning,  was,  an  hour  or  two  after- 
wards, driving  his  conveyance  over  a  high  bridge 
spaiuiing  a  deep  vaUey,  when  he  pulled  up  his 
horses,  and  remarking  to  his  passengers  that 
he  would  show  them  something  they  had  never 
seen  before,  committed  suicide  by  jumping  from 
the  parapet. 

Less  frequent  Sequelae. — Menorrhagia,  amenor- 
rhoca,  a  fit  in  epileptic  subjects,  and  hysteria, 
are  occasional  post-extractional  manifestations. 

EXTRACTION     UNDER     GENERAL 
ANAESTHETICS 

Choice  of  Anaesthetic. — The  selection  of  the 
most  suitable  anaesthetic  for  a  given  operation 
will  depend  on  several  factors,  such  as  the 
extent  or  difficulty  of  the  operation,  the  age 
and  bodily  state  of  the  patient,  the  skill  of  the 
operator,  and  the  knowledge  and  experience 
of  the  anaesthetist.  For  operations  that  can 
be  performed  in  thirty  seconds,  nitrous  oxide 
is  generally  used.  For  longer  operations  lasting 
up  to  ninety  seconds,  gas  and  ethyl  chloride  is. 


in  the  experience  of  the  writer,  the  best  anaes- 
thetic. It  nuist,  however,  be  used  under  strict 
limitations  as  to  dose  of  ethyl  chloride  (3  c.cm. 
being  regarded  as  the  maxinmm),  and  time  of 
administration,  which  should  never  exceed 
twenty-five  seconds  breatliing  of  the  mixture. 
The  ethyl  chloride,  in  a  measured  dose,  should 
be  poured,  not  squirted,  into  the  bag,  after  five 
to-and-fro  respirations  of  gas.i  While  believing 
that  the  mixture,  if  given  in  the  apparatus  and 
according  to  the  technique  advised  by  him,  is  as 
safe  as  nitrous  oxide,  pleasant  to  take,  and  free 
from  after-effects,  the  writer  would  not  advise 
its  indiscriminate  use  by  all  and  sundry ;  Ijut, 
as  in  the  case  of  all  anaesthetics,  would  limit  its 
employment  to  those  who  have  had  sufficiently 
extended  oijportunity  of  seeing  its  adminis- 
tration by  experts,  of  themselves  giving  it  under 
supervision,  and  of  receiving  adequate  instruc- 
tio'nin  the  admmistration  of  general  anaesthetics, 
the  difficulties  and  dangers  comiected  v,hh  an- 
aesthesia, and  the  methods  of  preventing  their 
occurrence  or  dealing  with  them  \\hen  they 
arise.  In  short,  a  man  can  only  practise  suc- 
cessfully what  he  has  been  \\e\\  taught,  and  to 
no  procedure  is  this  remark  more  aijplicable 
than  to  the  administration  of  anaesthetics. 

According,  therefore,  to  his  school  of  origin 
and  experience,  it  \\  ill  be  found  that  the  anaes- 
thetist prefers  continuous  gas,  gas  and  oxygen, 
gas  and  ether,  ether  preceded  by  gas  or  ethyl 
clUoride,  or  gas  and  ethyl  chloride.  These 
may  all  be  given  with  the  patient  in  the  sitting 
position.  Chloroform  is  at  once  the  most 
unsuitable  and  the  most  dangerous  anaesthetic 
to  employ  for  tooth  extraction,  and  sliould 
never  be  so  used.  In  gas,  alone  or  in  combina- 
tion with  oxygen,  ethyl  chloride,  or  ether,  the 
dentist  has  a  choice  of  reagents  of  proved 
efficiency  and  safetv. 

Procedure  in  Administration. — A  general  an- 
aesthetic should  not  be  given  shortly  after 
a  fuU  meal.  Midday,  after  a  light  breakfast 
at  8  a.m.  or  9  a.m.,  is  perhaps  the  best  time 
for  dental  operations.  All  tight  clothing  should 
be  loosened ;  collar,  necktie,  hat,  artificial 
teeth,  spectacles,  and  brooches,  should  be  re- 
moved. The  clothing  should  be  opened  to  give 
a  view  of  the  neck  and  episternal  notch,  so  that 
the  presence  of  any  s\\  elling,  e.  g.  goitre,  may  be 
detected.  The  chair  should  be  upright,  or  very 
slightly  tilted  back;  the  patient's  cranium  and 
trunk  should  be  in  a  straight  line  ;  the  head  must 
not  be  tlirown  back  nor  the  neck  stretched.  The 
crown  of  the  patient's  head  should  be  on  a 

1  Since  this  was  written  the  author  has  devised  a 
method  and  apparatus  for  administering  gas  and 
oxygen  alone  or  in  combination  witli  ethylcliloride  or 
ether.  He  believes  that  this  method  gives  eve 
greater  safety  and  freedom  from  aftereffects  than  tlie 
method  described  in  tlie  text. 


662 


level  with  the  operator's  breast.  The  hands 
should  be  clasped,  with  the  fingers  interlaced,  on 
the  lap.  The  legs  should  rest  easily,  not  crossed, 
and  the  feet  should  not  be  braced  against  the 
foot-rest.  The  patient  should  clear  the  throat 
and  blow  the   nose ;   it   may   be   necessary   to 


Fig.  906. 

remove  from  the  mouth  such  objects  as  lozenges, 
tabloids,  sweets,  or  quids  of  tobacco.  The  cloth- 
ing must  be  protected  by  a  waterproof,  washable, 
sterihzable  cover  ;  two  yards  of  Batiste  Mosetig, 
invented  by  Prof.  Mosetig  of  Vienna,  serve  this 
purpose  admirably.  A  mouth-prop  must  be  in- 
serted previous  to  adjusting  the  face-piece.  If 
the  mouth-prop  is  placed  at  one  side,  Sir  Frederic 
Hewitt's  are  the  best  (see  Fig.  906).  The 
writer  always  places  it  centrally  and  uses  a  prop 
with  surfaces  at  right  angles  to  the  stem.  The 
props  should  be  attached  to  a  neat  strong  chain 
instead  of  the  dirty  string  or  catgut  often  seen. 
An  inch  of  red  rubber  tubing  with  a  hole  cut  in 
one  side  makes  the  best  cover  for  these  props. 
All  props  with  springs,  racks,  or  other  complica- 
tions, are  anathema.  A  small  gag  should  be  used 
as  a  rule,  the  larger  size  being  reserved  for  cases 
in  which  the  incisors  are  wanting.  A  patient 
cannot  breathe  comfortably  with  the  mouth 
widely  propped  oiDen.  The  small  prop  at  the 
front  of  the  mouth  does  not  impede  the  swallow- 
ing movement  of  the  tongue,  as  does  the  prop 
at  the  side.  Here  let  a  protest  be  made  against 
the  expression,  so  often  heard,  "  the  tongue 
falling  back."  The  tongue  does  not  fall  back ; 
if  it  did,  every  one  would  Ije  asphyxiated  in 
sleep ;  in  anaesthesia  the  swallowing  reflex  is 
interfered  with  or  abolished,  and  the  tongue, 
arrested  in  the  middle  of  the  swallowing  move- 
ment, blocks  the  faucial  aperture  of  the  air- 
passages,  wlule  at  the  same  time  the  larynx  is 


closed  by  the  epiglottis.  ^Vhen  this  happens 
the  forefinger  should  be  passed  to  the  back  of 
the  mouth  and  the  base  of  the  tongue  depressed. 
It  is  advised  that  tongue-forceps  be  at  hand 
to  draw  forward  the  tongue ;  but  the  writer, 
though  he  accepts  and  endorses  the  advice,  has 
never  had  occasion  to  use  the  instrument.  For 
opening  the  mouth  further  during  anaesthe- 
sia, or  keeping  it  open  independently  of  the 
mouth-prop,  a  Mason's  or  Heister's  gag,  or  a 
wedge  mouth-opener  of  pewter,  aluminium,  or 
Britannia-metal,  will  be  needed.  An  expe- 
rienced anaesthetist  will  assist  the  extractor 
by  holding  the  patient's  head  and  manipulating 
the  mouth-opener. 

Most  anaesthetists  stand  on  the  right  of  or 
behind  the  chair  to  administer,  and  hold  the 
facepiece  in  the  left  hand.  It  is  more  con- 
venient to  stand  to  the  left  side  holding  the  face- 
piece  in  the  right  hand  (see  Fig.  907) .  Many  men 
never  apply  the  face-piece  properly.  It  should 
be  firmly  grasped  in  the  right  hand,  and  the 
point  placed  on  the  bridge  of  the  nose  ;  then 
gentle  pressure  downwards  and  towards  the  face 


secures  accurate  adaptation  without  constriction 
of  the  nose  or  compression  of  the  cheeks. 

Procedure  in  Operation. — It  is  not  the  writer's 
province  in  this  article  to  deal  with  the 
administration.  He  may,  however,  be  per- 
mitted to  emphasize  the  importance  of  elimi- 
nating  the    asphyxia     element  from   any  and 


663 


every  anaesthesia.  The  dentist  must  take 
care  that  there  is  no  raechaiiical  or  physical 
obstniction  to  respiration,  and  that  the  blood 
is  sufficiently  aerated  during  induction  and 
operation.  He  must  guard  against  a  block- 
ing of  the  airway  by  the  tongue,  blood,  saliva, 
mucus,  pus,  extracted  teeth,  or  foreign  bodies, 
such  as  swabs  or  sponges.  He  must  not,  while 
extracting,  force  back  the  tongue  against  the 
fauces,  or  neglect  to  support  the  mandible  with 
the  left  hand.  He  must  train  the  finger  and 
thumb  of  his  left  hand  to  take  charge  of  the 
tooth,  and  prevent  its  backward  passage,  to  the 
pharynx  or  air-passages.  He  must  refrain 
from  throwing  the  patient's  head  far  back, 
thereby  increasing  the  risk  of  this  accident. 
He  must  make  certain  that  the  whole  of  the 
extracted  tooth  is  in  every  case  out  of  the 
mouth;  if  a  tooth  or  root  fall  on  the  tongue, 
or  into  the  sulcus  of  the  cheek,  the  head  must 
be  thrown  forward  and  the  tooth  removed  before 
another  extraction  is  attempted. 

Patients  ought  to  know  that  the  bladder 
should  not  be  full  or  the  lower  bowel  loaded. 

In  cases  where  the  removal  of  one  or  more 
teeth  is  imperative,  and  of  others  advisable, 
it  is  often  wise  to  make  sure  of  the  more  im- 
portant ones  first ;  but,  speaking  generally,  if  a 
number  of  teeth  are  to  be  removed,  it  is  best  to 
adopt  a  definite  order  of  procedure.  Take  the 
extreme  case  of  "  clearing  a  mouth ".  The 
fewer  instruments  the  operator  uses,  the  less 
time  «dll  he  consume  in  changing  them.  He 
should  begin  on  the  left  side  of  the  mandible 
and  work  from  the  back  forwards.  He  need 
not  strain  this  rule,  if  for  example  the  extrac- 
tion of  the  second  molar  first  would  facilitate 
the  removal  of  the  third  molar.  Assuming  tlie 
prop  to  be  centrally  placed,  he  extracts  the 
left  lower  teeth  to  the  canine  inclusive,  and 
crosses  to  the  right  side,  behind  the  chair.  He 
should  never  pass  in  front  of  the  patient,  be- 
cause it  takes  longer,  and  involves  the  risk  of 
stumbling  over  the  foot-rest ;  or,  worse  still,  of 
disarranging  his  dress  by  catching  on  the  arm 
of  the  chair — an  accident  that,  occurring  to  a 
dentist  imprudent  enough  to  give  an  anaesthetic 
to  and  operate  on  a  female  patient  without  the 
presence  of  a  third  party,  preferalily  of  the 
gentler  sex,  may  involve  his  being  charged  with 
a  criminal  assault.  The  lower  teeth  on  the 
right  side  are  taken  to  the  canine.  The  operator 
steps  dowii,  takes  his  upper  forceps,  and  re- 
moves first  the  cheek  teeth  on  the  left,  then  the 
same  teeth  on  the  right  side,  begiiming  always 
at  the  back  and  working  forwards.  The  anaes- 
thetist or  assistant  inserts  a  Mason's  gag  or  a 
wedge  on  the  left  side,  the  central  prop  is  re- 
moved, and  the  operation  completed  by  the 
extraction   of   the   anterior   teeth,    upper   and 


lower.  The  procedure  described  may  be  varied 
by  extracting  all  the  mandibular  teeth  before 
proceeding  to  the  upper  teeth. 

The  operation  of  "clearing  the  mouth"  is, 
or  should  be,  rare  in  private  practice,  and 
attention  to  dental  hygiene  would  render  it 
very  infrequent  in  hospital  patients.  Even 
when  it  ajjpears  necessary,  it  will  often  be  more 
judicious  to  do  it  at  two  sittings,  taking  the 
lower  teeth  at  the  first,  and  the  upper  teeth  at 
the  second,  or  the  upper  and  lower  teeth  of  the 
same  side  at  each  sitting.  Inasmuch  as  the 
risk  of  sepsis  is  increased  in  extensive  extrac- 
tions in  dirty  mouths,  every  antiseptic  precau- 
tion inculcated  in  the  earlier  part  of  this  chapter 
must  be  strictly  observed. 

The  collective  area  of  an  extensive  extraction 
wound  is  large  ;  till  the  gums  heal,  solid  food  is 
impossible,  and  nutrition  is  apt  to  be  impaired ; 
haemorrhage  and  .shock  are  also  factors  antagon- 
istic to  speedy  recovery.  The  importance  of 
the  operation  and  its  attendant  risks  need  not 
be  exaggerated  to  the  point  of  frightening  the 
patient  and  paralysing  the  operator,  but  on 
the  other  hand  they  need  not  be  minimized  or 
recklessly  ignored. 

One  word  of  advice  in  conclusion  :  during 
the  administration  and  extraction,  "  Watch  the 
breathing  "  ;  after  the  operation,  "  Attend  to 
the  wound  ". 

W.  G. 


BIBLIOGRAPHY 

( 1 )  Bennett,  Norman  G.     Pye'a  Surgical  Handicraft, 

1909. 

(2)  BowDEN,    G.    H.    Case    of    Deafness     following 

Bilateral  Dislocation  after  Extraction  of  Molars. 
Trans.  Odonl.  Soc,  1896-7,  p.  90. 

(3)  Coleman,  F.     Extraction  of  the  Teeth. 

(4)  Davies,  .John  D.     Pulmonary  Abscess  caused  by 

a    Tooth.     Brit.   Dent.    Jour.     Dental   Cosmos, 

1907,  Vol.  XLIX,  p.  98. 

(5)  Endelman,   Julio.      Notes   on   Therapeutics   of 

the   Accidents  of   Extraction.     Dental  Cosmos, 
1905,  Vol.  XLVII,  p.  348. 

(6)  Inolis,   O.   E.     Post-extraction  Sequelae.     Dental 

Cosmos,   1909,  Vol.  LI.  p.  695. 

(7)  J.\MES,  W.  W.     Extravasation  of  Blood  into  Neck 

following    Extraction    of    Third    Lower  Molar. 
Trans.  Odont.  Soc,   1906-7,  p.   104. 

(8)  LiNiATSCHECK.     Post-extraction  Pain.      Deutsche 

Monatschrift    far   Zahnheilkunde,     Nov.     1904. 
Dental  Cosmos,  1905,  Vol.  XLVII,  p.  145. 

(9)  Parfitt,  J.  B.     Mechanical  Principles  of  Extrac- 

tion.     Trans.  Odont.  Soc,   1906-7,  p.  44. 

(10)  PVE,  Walter.     Pye's  Surgical  Handicraft,   1908, 

pp.  31,  32. 

(11)  Smale  and  CoLYEB.     Diseases  and  Injuries  of  the 

Teeth,  2nd  ed.,  p.  567. 

(12)  Tomes.     Dental   Physiology    and    Surgery,    1848, 

pp.   325-327. 

(13)  Tomes  and  Nowell.     Dental  Surgery,    1906. 

(14)  Vorslund-Kj.\er,    Prof.     Permanent     Insensi- 

bility   of     Inferior    Dental     Nerve,  caused     by 
Extraction  of  Lower  Wisdom.     Dental  Cosmos, 

1908,  Vol.  L,  p.  1151. 


CHAPTER   XLI 


LOCAL   ANAESTHESIA 


Local  anaesthetics  may  be  defined  as  sub- 
stances tliat  temporarily  destroy  sensation  in 
a  circumscribed  area  of  tissue,  by  interfering 
with  the  functions  of  the  terminations  of  the 
sensory  nerves. 

From  early  times  many  methods  have  been 
adopted,  and  various  substances  used  in  an 
endeavour  to  bring  about  a  freedom  from  pain 
during  a  surgical  operation.  The  methods  in 
use  in  dentistry  at  the  present  time  are  : 
Firstly,  the  application  to  the  part,  of  volatile 
substances,  which  act  by  lowering  the  tempera- 
ture of  the  tissues,  and  thus  paralysing  the 
terminations  of  the  sensory  nerves;  this  is 
merely  a  further  advance  on  older  methods, 
which  attempted  by  the  application  of  cold 
substances  to  the  part  to  be  operated  on,  to 
bring  about  a  certain  degree  of  numbness. 
Secondly,  the  application  to  mucous  surfaces 
of  drugs  cajjable  of  being  absorbed,  and  by  their 
action  on  the  nerve  fibres  producing  local 
anaesthesia.  Thirdly,  the  injection  into  the  tis- 
sues themselves  of  solutions  of  drugs  capable 
of  causing  local  anaesthesia  of  the  part. 

The  first  of  the  volatile  substances  to  be  used 
for  freezing  the  tissues  was  the  ether  sjiray 
introduced  in  1866  by  Sir  W.  Richardson.  This 
spray,  when  allowed  to  play  on  the  part,  caused 
intense  cold,  brought  about  by  the  rapid 
evaporation  ;  and  anaesthesia  was  produced  by 
the  paralysis  of  the  terminations  of  the  sensory 
nerves.  Although  there  is  no  record  that  this 
particular  spray  was  ever  used  in  dentistry,  the 
substances  introduced  later,  which  were  even 
more  volatile,  such  as  ethyl  chloride  and  methyl 
chloride,  and  also  various  mixtures  of  the  two 
in  varied  proportions,  have  been  extensively 
used  to  produce  local  anaesthesia  in  dental 
operations. 

Ethyl  Chloride  is  a  gas  at  ordinary  tempera- 
tures, but  under  pressure  is  condensed  into  a 
colourless  liquid,  having  a  sweet  burning  taste, 
and  a  characteristic  pungent  odour.  It  boils 
at  about  50°  F.,  and  is  very  inflammable, 
burning  with  a  green  flame  and  setting  free 
hydrochloric  acid.  It  readily  volatilizes  when 
liberated  at  ordinary  temperatures,  more 
readily  if  it  is  aided  by  a  little  heat,  such  as  that 
of  the  hand.  It  is  usually  supplied  in  glass  or 
metal  capsules,  either  sealed  or  fitted  with  some 
form  of  metal  stopcock  or  screw  stopper.     The 


664 


opening  from  the  capsule  is  exceedingly  minute, 
in  order  to  allow  the  gas  to  escape  in  a  fine 
spray.  It  is  used  for  the  extraction  of  teeth, 
and  for  many  minor  operations  about  the  mouth, 
but  its  use  is  rather  restricted  to  the  anterior 
part  of  the  mouth,  on  account  of  the  difficulty 
of  directmg  a  spray  on  to  the  tissues  in  the 
posterior  region.  The  freezing  should  not  be 
too  prolonged,  nor  used  for  patients  who  have 
a  poor  circulation,  as  the  blood-supply  may  be 
so  cut  off  as  to  bring  about  a  condition  which 
has  been  likened  to  a  chilblain,  or  frost-bite, 
and  which  may  lead  to  gangrene  of  the  part, 
unless  the  circulation  is  restored  in  time.  For 
the  same  reason  it  is  not  advisable  to  employ 
it  where  there  is  extensive  inflammation,  as  the 
circulation  may  be  more  readily  cut  off  in  tissues 
where  vitality  is  already  lowered  and  stasis  has 
occurred.  Its  use  is  not  advised  in  acute  inflam- 
mation of  the  pulp,  or  acute  periodontitis,  on 
account  of  the  intense  pain  produced  during  its 
application.  Where  it  is  to  be  used  for  the  ex- 
traction of  a  tooth  with  an  exposed  pulp,  or  in 
the  neighbourhood  of  one,  care  should  be  taken 
to  protect  the  pulp  first,  by  means  of  some 
fiUing,  and  an  endeavour  should  be  made  to 
direct  the  spray  towards  the  apex  of  the  tooth 
and  away  from  the  crown.  The  inhalation  of 
the  vapour,  even  though  only  a  small  quantity, 
may  bring  about  a  jjartial  general  anaesthesia, 
and  for  this  reason  the  method  should  not  be 
used  for  patients  who  are  habitually  mouth- 
breathers. 

Method  of  Ajyplication. — The  part  to  be 
sprayed  should  first  be  thoroughly  cleansed, 
and  then  dried.  Wool  rolls  and  napkins  should 
be  so  arranged  as  to  protect  the  surrounding 
tissues,  and  to  prevent  the  vapour  being  sprayed 
on  the  back  of  the  mouth  or  throat.  The  glass 
capsule  is  held  in  the  hand  with  the  nozzle 
directed  away  from  the  patient,  and  the  warmth 
of  the  hand  hastens  the  volatilization  of  the 
liquid ;  the  spray  is  then  directed  on  to  the 
tissues,"  the  capsule  being  held  some  six  or 
eight  inches  away,  so  as  to  ensure  the  ethyl 
chloride  reaching  the  tissues  in  the  form  of 
vapour.  When  the  tissues  appear  white  and 
covered  with  crystals,  the  spray  should  be 
arrested,  and  the  operation  quickly  performed, 
as  the  anaesthesia  is  not  of  very  long  duration. 

The  second  metliod  employed  is  that  of  the 


665 


application  to  the  mucous  membrane  of  drugs, 
or  solutions  of  drugs,  that  are  capable  of  being 
absorbed,  and  by  their  action  on  the  sensory 
nerves  dull  the  sensibility  to  pain.  Cocaine  is 
one  of  the  chief  drugs  used  for  this  purpose, 
but  the  result  is  merely  superficial,  and  does 
not  render  it  of  very  great  value  in  the  mouth, 
except  for  very  slight  operations.  A  very  much 
stronger  solution  of  the  drug  may  be  used  in 
this  manner  than  would  be  injected,  but  care 
should  be  taken  to  limit  its  action  to  a  small 
area,  by  protecting  the  surrounding  parts. 
Sufficient  time  must  also  be  allowed  for  ab- 
sorption. Electrical  currents  have  been  used 
to  aid  the  diffusion  of  the  drugs,  but  the  un- 
certainty of  the  results  produced,  and  the  time 
required,  have  rendered  this  method,  in  dentistry 
at  any  rate,  almost  olisolete. 

ANAESTHESIA    BY    INJECTION 

The  method  most  in  practice  at  the  present 
time  is  the  injection,  by  means  of  a  syringe, 
of  solutions  of  drugs,  which  by  infiltration  of 
the  tissues,  and  by  their  action  on  the  nerve 
filaments  in  close  proximity  to  the  part  to  be 
operated  on,  bring  aliout  the  desired  result. 
In  general  surgery  this  is  carried  further,  by 
the  injection  into  a  nerve-trunk,  in  order  to 
produce  anaesthesia  in  the  course  supplied  by 
the  nerve,  and  is  known  as  "  regional  anaes- 
thesia ".  This  method,  however,  is  not  em- 
ployed in  dentistry. 

Before  discussing  the  various  drugs  used  for 
this  purpose,  it  may  be  as  well  to  consider  what 
are  the  advantages  and  disadvantages  of  this 
method  as  compared  with  a  general  anaesthetic, 
and  in  doing  this  it  will  be  taken  for  granted 
that  its  chief  use  would  be  for  the  extraction 
of  a  tooth  or  teeth,  though  of  course  its  use  is 
not  limited  to  this. 

The  advantages  of  this  method  over  nitrous 
oxide  inhalation  are  :  No  special  preparation 
on  the  part  of  the  patient  is  necessary ;  in 
contradistinction  from  nitrous  oxide  anaesthesia 
it  is  rather  preferable  to  inject  after  a  meal 
than  some  time  before,  as  this  enaljles  a  patient 
better  to  withstand  any  shock.  The  length  of 
time  the  anaesthesia  lasts  by  this  method  is 
considerably  longer,  thus  allowing  ample  time 
for  a  difficult  extraction ;  it  also  permits  a  very 
careful  preliminary  exploration  to  be  made 
painlessly.  The  patient  remains  quieter  during 
the  operation  ;  this,  with  the  additional  time, 
enables  the  extraction  to  be  accomplished  with 
less  laceration  of  the  tissues.  The  after-pain 
of  extraction  is  very  much  diminished,  if  only 
a  suitable  strength  of  the  drug  has  been  injected, 
and  not  more  than  a  sufficient  quantity  of  the 
solution.  Some  writers  maintain  that  the  pain 
is    often    very    severe    some    hours    after    the 


operation ;  but  except  in  a  very  few  cases 
this  does  not  occur,  and  when  it  does  it  rather 
points  to  some  error  in  judgement,  such  as 
injecting  in  an  unsuitable  case,  or  the  use  of  a 
too  powerful  strength  of  the  drug.  Besides  the 
cases  in  which  the  injection  of  any  particular 
di'ug  is  contra-indicated,  one  of  the  disadvan- 
tages of  this  method  over  a  general  anaesthetic 
is  that  a  nervous  patient  is  conscious  of  the 
manipulation  of  the  instruments,  although  not 
feeling  pain.  This  difficulty  can,  however,  as  a 
rule  be  overcome,  except  in  the  case  of  neur- 
asthenic patients,  to  whom  should  be  given  a 
general  anaesthetic.  Against  this  may  be  placed 
the  fact  that  a  patient  who  has  once  experienced 
local  anaesthesia  has  less  dread  of  it  than  many 
patients  have  of  a  second  administration  of  a 
general  anaesthetic. 

It  is  claimed  against  this  method  that  it  is 
more  dangerous,  but  this  need  not  be  so  now, 
if  its  use  is  limited  to  suitable  cases.  It  was 
undoubtedly  true  before  it  was  recognized  that 
nothing  like  the  dose  of  the  drugs  formerly 
given  was  necessary,  and  also  before  the  addition 
of  adrenalin  chloride  to  solutions  to  limit  the 
action  of  the  ckug  to  a  circumscribed  area  ;  now, 
however,  with  a  minimum  amount  of  the  drug 
in  an  isotonic  solution  it  need  be  no  more 
dangerous  than  any  other  anaesthetic.  The 
healing  is  said  by  some  to  be  delayed  by  this 
method,  but  this  is  not  borne  out  clinically. 
Where  such  was  the  case  it  may  have  been  due 
rather  to  an  unsuitable  strength  of  the  drug,  or  to 
the  condition  of  the  tissues  having  been  un- 
healthy, thus  not  permitting  the  return  of  the 
blood  to  the  part  sufficiently  soon  for  healthy 
healing. 

Although  it  may  be  conceded  that  this 
method  has  many  advantages  to  recommend 
it,  yet  it  should  in  no  wise  be  looked  upon  as  a 
simple  and  easy  operation.  Great  care  should 
be  exercised,  and  experience  is  necessary  in 
the  use  of  drugs,  which  are  in  many  cases  strong 
protoplasmic  poisons. 

Warning  is  necessary  in  the  case  of  multijjle 
extractions,  as  there  is  great  danger  that,  on 
account  of  the  prolonged  anaesthesia  that  can 
be  obtained,  too  much  may  be  attempted  at  one 
time.  It  is  frequently  not  realized  that  the 
operation  of  tooth  extraction  entails  consider- 
able shock  to  the  system,  and  although  symptoms 
of  it  may  not  appear  at  the  time,  the  effects  of 
it  are  often  felt  for  some  considerable  period 
afterwards.  This  is  perhaps  one  of  the  greatest 
dangers  of  local  anaesthesia,  and  it  cannot  be 
too  strongly  urged  that  where  it  is  necessaiy 
to  extract  several  teeth  at  one  time,  the  patient 
should  be  kept  under  observation  afterwards, 
and  should  be  treated  exactly  as  he  would  be 
after  a  minor  surgical  operation,  and  where 
possible,  kept  in  a  reclining  position. 


666 


The  use  of  this  method  of  produchig  anaes- 
thesia is  not  recommended  for  young  cliildren, 
as  although  they  are  frequently  good  subjects 
for  it,  yet  the  technique  of  the  injection,  and 
their  consciousness  of  aU  that  is  being  done,  is 
rather  apt  to  frighten  them ;  whereas  in  the 
case  of  a  general  anaesthetic  they  veiy  soon 
reach  an  unconscious  state,  and  rarely  dread  a 
repetition  of  it  at  a  future  date. 

It  is  not  advisable  to  inject  into,  or  near,  very 
inflamed  tissues,  as  besides  the  pain  caused  by 
so  doing,  the  vitality  of  the  tissues,  already 
lowered,  is  liable  to  be  further  reduced  by  the 
action  of  the  drugs  used  ;  moreover,  the  absence 
of  blood-supply  for  some  time  may  cause 
sloughing  and  death  of  the  tissues.  There  are 
other  factors  to  be  taken  into  consideration 
in  injecting  certain  drugs,  which  will  be  con- 
sidered when  these  drugs  are  discussed. 

Cocaine  was  the  first  drug  to  be  used,  by 
injection,  to  produce  local  anaesthesia. 

Cocaine  Hydrochloride  is  the  hydrochloride 
of  an  alkaloid  extracted  from  coca-leaves 
(Erythroxylon  Coca).  It  was  first  obtained  in 
1860  by  Gaedeke,  but  its  use  by  injection  was 
first  suggested  by  Koller  in  1884.  It  consists 
of  colourless  crystals  or  a  crystalline  powder, 
soluble  2  in  1  of  water,  1  in  3  of  alcohol 
and  1  in  3  of  glycerine.  It  has  a  bitter  taste 
and  produces  on  the  tongue  a  tingling  sensation, 
followed  by  numbness.  Aqueous  solutions  are 
neutral  to  litmus  jmper.  Solutions  do  not  keep 
well  on  account  of  the  growth  of  a  fungus  in 
them  ;  to  prevent  this,  boric  acid  or  salicylic 
acid  is  added  to  the  solution ;  it  is,  however, 
better  to  make  fresh  solutions  from  the  salts 
as  they  are  required.  Prolonged  boiling  breaks 
it  up  into  ecgonine  and  other  compounds ;  but 
it  is  maintained  by  some  writers  that  such  boiling 
as  is  necessary  for  sterilization  does  not  impair 
its  anaesthetic  action,  and  that  the  ecgonine  is 
present  in  such  a  small  quantity  as  to  be  non- 
irritant.  Its  local  action  on  injection  is  a 
selective  one  for  some  of  the  terminations  of 
the  sensory  nerves,  especially  those  conve_>dng 
impressions  of  pain  and  touch.  It  has  a  vaso- 
constrictor action  on  the  vessel  walls,  producing 
contraction  of  the  vessels  and  a  perceptible 
blanching  of  the  tissues. 

Its  general  action  is,  firstly,  one  of  stimulation 
of  the  central  nervous  system,  which  may  be 
evidenced  by  some  excitement  in  either  speech 
or  movement ;  this  is  followed  by  depression. 
Respiration  is  accelerated  owing  to  central 
.stimulation,  and  the  rapidity  and  depth  of 
breathing  is  increased  ;  later,  depression  follows, 
and  as  it  progresses  the  amount  of  air  in- 
spired with  each  breath  becomes  less,  and  may 
cease  altogether.  The  circulation  is  altered 
owing  to  its  action  on  the  heart  and  on  the 
vessels,  and  the  pulse  is  quickened;    later,  it 


becomes  slow  and  \^•eak,  and  collaj)se  may  take 
place. 

The  dose  by  the  stomach  is  |  gr. ;  for  dental 
operations  J  gr.  is  considered  a  safe  dose,  in  a 
weak  solution  of  |  per  cent  or  1  per  cent  ten  to 
fifteen  minims  being  usually  required.  Sauvez 
(15)  recommends  that  not  more  than  1  c.cm.  of 
1%  solution  should  be  injected  at  one  time  in  a 
sitting  position  ;  if  more  is  required  the  patient 
should  be  placed  in  a  recumbent  position,  and 
kept  in  that  position  for  some  time  afterwards. 
All  clothes  that  impede  respiration  should  be 
loosened.  The  toxic  action  of  cocaine  even 
in  small  doses  is  very  uncertain,  and  it  is  this 
that  makes  cocaine  a  dangerous  drug  to  use 
indiscriminately. 

Symptoms  of  toxic  action  differ  in  different 
individuals.  They  may  first  appear  as  some 
excitement  or  restlessness  on  the  part  of  the 
patient ;  or  there  may  be  merely  a  calm  languid 
condition.  The  pulse  is  quickened,  the  breath- 
ing is  quick  and  deep,  the  pupils  are  dilated, 
headache  and  a  feeling  of  sickness  may  be  com- 
plained of,  the  mouth  is  often  dry,  and  there  is 
a  profuse  perspiration.  The  breathing  becomes 
rapid  and  dyspnoeic,  and  may  finally  be  arrested 
during  convulsions.  Li  other  cases  there  may 
be  no  convulsive  movements,  merely  faulting 
and  collapse,  with  the  heart-beat  slow  and  weak 
and  the  respiration  feeble ;  either  of  these  may 
gradually  cease. 

There  is  no  known  antidote  for  cocaine. 
Place  the  patient  quickly  in  a  recumbent 
position,  loosen  all  clothes  that  may  in  any  way 
impede  respiration,  allow  plenty  of  air  to  get 
to  the  patient,  cover  tlie  lower  limbs  and  keep 
them  as  warm  as  possible,  give  stimulants  and 
inlialations  of  ammonia,  and  if  necessary  employ 
artificial  respiration.  Cocaine  should  never  be 
emjjloyed  for  people  with  heart-disease,  nor 
for  those  suffering  from  any  affection  of  the 
lungs,  or  other  organs  of  respiration  ;  nor  should 
it  be  injected  in  anaemic  people,  or  those  weak- 
ened by  iUness ;  and  because  of  its  depressive 
action  it  should  not  be  used  for  neurasthenic 
people,  or  where  there  is  locally  intense  in- 
flammation, such  as  spongy  inflamed  gums. 

Wlien  cocaine  was  first  extensively  used  as  a 
local  anaesthetic,  the  dose  injected  was  usually 
too  great,  and  sufficient  care  was  not  perhaps 
taken  to  ensure  that  the  patient  was  in  a  fit 
condition,  with  the  consequence  that  the 
cocaine  was  absorbed  into  the  system,  and  toxic 
symptoms  occurred  rather  frequently.  Tluis 
cocaine  came  to  be  looked  upon  as  too  dangerous  ; 
later,  adrenalin  chloride  was  added  to  solutions 
to  cause  further  contraction  of  the  vessels,  and 
so  limit  the  action  of  the  drug  to  a  small  area. 

Adrenalin  Hydrochloride,  known  also  as  epi- 
nephrine, suprarenin,  and  under  many  other 
names,   is   the    hydrochloride    of   a   substance 


667 


obtained  from  the  suprarenal  capsules  of  sheep 
and  oxen.  It  is  a  greyish  powder,  slightly 
soluble  in  cold  water,  but  more  freely  in  warm 
water.  Aqueous  solutions  ^^•hen  fresh  are 
colourless ;  if  allowed  to  be  submitted  to  the 
action  of  light  or  air,  they  become  oxidized  and 
lose  their  properties.  It  remains  stable  much 
longer  in  the  dry  state.  It  is  a  powerful  vaso- 
constrictor, acting  on  the  muscular  coat  of  the 
smaller  arteries,  and  when  applied  to  a  mucous 
membrane,  even  in  dilute  solution,  produces  a 
local  ischaemia ;  on  injection  its  action  is 
increased,  causing  complete  contraction  of  the 
vessels.  If  used  in  weak  solutions  and  not  in 
too  great  quantity  its  action  is  only  local ;  but 
when  injected  in  large  doses  it  causes  great 
acceleration  of  the  heart's  action,  and  a  rapid 
rise  in  blood  pressure,  wliich  is  followed  by  a 
slowing  or  arrest  of  the  heart ;  respiration  slows 
and  may  cease  with  expiration.  For  applica- 
tion to  mucous  membranes  an  aqueous  solution 
of  1  in  1000  is  used,  but  for  injection  this  should 
be  diluted  to  1  in  10,000  or  1  in  100,000,  in 
normal  saline  solution.  Adrenalin  possesses  no 
anaesthetic  value  itself,  but  when  injected  in 
combination  with  other  drugs,  it  not  only 
restricts  their  absorption  to  a  limited  area,  but 
at  the  same  time  permits  them  to  exercise  a 
much  more  jjowerful  action  by  so  doing ;  it 
also  permits  the  operation  to  be  performed 
bloodlessly.  This  latter  may  or  may  not  be 
of  advantage,  but  it  is  claimed  that  its  jjower 
of  restricting  absorption  has  had  a  marked 
influence  on  the  usefulness  of  local  anaesthetics. 

Cocaine,  though  good  from  an  anaesthetic 
point  of  view,  has  disadvantages,  both  from  its 
limitation  of  u.se  in  certain  cases,  and  the 
uncertainty  of  its  toxic  effects ;  so  that  many 
substances  have  been  introduced  with  the 
object  of  supplying  an  anaesthetic  without  these 
disadvantages.  Among  these  are  eucaine  and 
tropacocaine,  stovaine,  and  novocaine. 

Eucaine  is  a  synthetic  product  artificially 
produced  from  a  base  analogous  to  ecgonine. 
At  first  two  alkaloids  were  used,  alpha  and  beta, 
but  the  former  was  discarded  on  account  of 
its  irritant  properties.  Of  beta-eucaine  the 
hydrochloride  and  lactate  are  Ijoth  used.  The 
former  appears  as  small,  white,  opaque  crystals 
soluble  in  water,  1  in  30 ;  it  is  usually  used 
as  a  3  or  4%  solution  for  injection,  and  i  gr. 
may  be  safely  injected.  A  good  anaesthesia 
may,  however,  be  obtained  with  a  2%  solution, 
but  to  obtain  this  solution,  the  salt  must 
be  dissolved  in  warm  water,  and  it  is  more 
readily  dissolved  in  a  sodium  chloride  solution. 
The  lactate  is  preferred  by  many  on  account 
of  its  greater  solubility,  1  in  5  of  water.  The 
lactate  contains  in  119  grs.  the  .same  amount  of 
the  eucaine  base  as  100  grs.  of  the  hydro-chloride. 

The  properties  of  eucaine  are  similar  to  those 


of  cocaine,  except  that  it  has  a  vaso-dilator 
action  instead  of  a  vaso-constrictor.  It  has 
been  extensively  used,  the  advantages  claimed 
for  it  being  a  lesser  toxicity,  and  also  that  it  does 
not  decompose  on  boiling.  Its  disadvantages 
are,  that  it  is  rather  more  irritating  to  the 
tissues,  that  it  does  not  diffuse  so  readily  as 
cocaine,  and  that  swelling  is  more  likely  to 
occur.  Anaesthesia  is  not  produced  so  rapidly  ; 
at  least  seven  or  eight  minutes  must  be  allowed 
to  elapse  after  injection  before  operating.  Its 
effect  does  not  last  nearly  so  long  as  cocaine. 
Adrenalin  is  often  used  in  combination  with 
eucaine,  but  its  addition  has  not  the  same  effect 
as  in  the  case  of  cocaine ;  eucaine  lessens  the 
action  of  adrenalin  while  cocaine  enliances  it, 
probably  because  eucaine  has  a  vaso-dilator 
action  and  so  retards  the  action  of  adrenalin. 

Tropacocaine  is  derived  from  a  source  similar 
to  cocaine  ;  it  is  obtained  from  the  leaves  of 
Java  coca.  The  hydrochloride  is  the  salt  used, 
it  is  freely  soluble  in  water,  solutions  of  it  may 
be  boiled  without  change,  and  solutions  are 
said  to  keep  well.  Sauvez  considers  it  inferior 
to  cocaine  in  anaesthetic  value,  and  equally 
to.xic ;  others  have  placed  its  toxicity  between 
that  of  cocaine  and  eucaine.  It  has  been 
extensively  used  in  dentistry  in  Germany, 
and  has  been  found  successful  without  being 
dangerous.  It  is  used  as  a  3%  solution, 
10-20  minims  being  injected.  Anaesthesia  lasts 
about  ten  miiuites ;  it  has  a  vaso-dilator 
action,  and  is  said  to  differ  from  the  other  drugs 
by  preventing  the  action  of  adrenahn  cliloride 
when  used  in  conjunction  with  it.  Le  Brocq, 
however,  found  that  if  fresh  solutions  were  used 
the  two  drugs  could  be  successfully  combined. 

Stovaine,  discovered  by  Fourneau  in  1904,  is 
the  name  given  to  a  hydrochloride  of  beta- 
amyline,  which  is  a  derivative  of  the  tertiary 
series  of  amino-alcohols.  It  crystallizes  in 
scales,  and  is  easily  solulile  in  water,  1  in  13,  and 
is  slightly  acid  in  reaction.  Aqueous  solutions 
can  be  sterilized  by  boiling  without  decomposi- 
tion. It  has  less  to.xicity  than  cocaine,  and  ha? 
a  slight  vasodilator  action;  it  is  said  also  to 
possess  slight  germicidal  properties,  and  a  tonic 
action  on  the  heart. 

The  anaesthesia  produced  is  not  so  good  as 
with  cocaine,  and  there  is  some  pain  (in  injec- 
tion. Gangrene  has  been  noted  at  the  point 
of  injection,  but  po.ssibly  too  strong  a  solution 
was  used;  Reclus  (14)  recommends  a  1% 
solution,  and  says  that  its  injection  caused 
only  a  slight  sensation  of  smarting,  and  that 
gangrene  does  not  take  place.  He  came  to 
the  conclusion  that  anaesthesia  w'as  .slower  in 
coming,  and  quicker  in  disappearing,  than  with 
cocaine.  Braun  (1)  considered  it  weaker  in 
anaesthetic  action,  and  that  it  possessed  no 
advantages  over  cocaine  and  eucaine. 


668 


It  has  been  extensively  used  in_surgery  to 
produce  spinal  anaesthesia. 

Novocaine  is  a  synthetic  product  discovered 
by  Eiiihorn  ;  it  is  an  amino-alcohol  of  the  ethane 
series  combined  with  the  radicle  of  para-amido- 
benzoic  acid.  The  hydrochloride  consists  of 
a  white  crystalline  powder,  which  is  readily 
soluble  in  cold  water.  Solutions  react  neutrally 
to  litmus  paper,  and  can  be  boiled  without 
decomposition.  It  has  a  slight  vaso-dilator 
action,  and  possesses  the  same  action  on  the 
peripheral  nerves  as  cocaine.  The  resjiiratory 
and  circulatory  systems  are  only  affected  by 
very  large  doses.  It  has  no  harmful  action  on 
the  tissues,  causing  no  irritation  or  sweUing  on 
injection.  The  drug  is  usually  used  in  combina- 
tion with  adrenalin  chloride,  and  it  is  claimed 
that  a  smaller  amount  is  then  required ;  the 
action  of  the  adi'enalin  is  not  lessened  by  the 
novocaine,  and  as  the  anaesthetic  properties  of 
the  latter  are  not  interfered  with,  and  the 
adrenalin  limits  the  action  of  the  novocaine  to  a 
circumscribed  area,  a  very  small  quantity  is 
needed.  In  dental  operations  it  is  usually  used 
either  as  a  2  %  or  1  %  solution ;  the  latter  is 
ample  for  most  operations,  and  J  gr.  is  usually 
sufficient,  though  it  may  safely  be  used  up  to 
1  grain. 

Li  a  large  series  of  experiments,  Le  Brocq 
(8)  has  investigated  the  relative  suitability  of 
drugs  used  as  a  substitute  for  cocaine  in  local 
anaesthesia.  The  points  that  he  investigated 
were  based  on  the  postulates  laid  down  by 
Braun  as  being  essential,  viz. — 

(1)  That  it  should  have  a  lower  toxicity  than 

cocaine,  in  proportion  to  its  local 
anaesthetic  value. 

(2)  That  it  should  possess  sufficient  solubility 

in  water,  and  that  solutions  should  keep 
without  deterioration  and  be  capable  of 
sterilization  by  boiling. 

(3)  That  there  should  be  no  mjury  to  the 

tissues,  and  that  it  should  be  easily 
absorbed,  without  causing  any  after- 
effects. 

(4)  That  it  should  be  capable  of  being  com- 

bined with  adrenalin. 

(5)  That  it  shoulcT  penetrate   mucous  mem- 

brane rapidly,  and  be  suitable  for 
medullary  anaesthesia. 

Among  the  drugs  he  investigated  were  beta- 
eucaine  lactate,  novocaine,  stovaine,  and  tropa- 
cocaine. 

In  anaesthetic  action  alone,  he  came  to  the 
conclusion  tliat  stovaine  was  more  powerful, 
weight  for  weight,  than  the  others,  wliich  were 
about  equal  to  cocaine.  With  regard  to  toxi- 
city, after  numerous  experiments  on  animals 
to  find  the  minimum  lethal  dose,  he  found  that 
by  taking  the  toxicity  of  cocaine  as  1-0,  stovaine 


would  be  rejjresented  by  0-625,  tropacocaine 
by  0'500,  novocaine  by  0-490,  and  beta-eucaine 
lactate  by  0-414.  In  solubility  he  ruled  out 
those  not  capable  of  forming  a  2  %  solution 
in  cold  water,  thus  excluding  eucaine  hydro- 
chloride, as  a  2  %  solution  of  this  drug  can 
only  be  obtained  in  warm  water.  The  others 
are  all  freely  soluble,  and  their  solutions  are 
capable  of  being  boiled  and  are  stable.  As  to 
their  irritant  action,  he  found  by  experiments 
on  animals  with  antiseptic  precautions,  inject- 
ing 10  minims  of  a  10  %  solution,  that  cocaine 
caused  swelling  and  hyperaemia ;  stovaine  caused 
intense  hyperaemia  with  dilatation  of  blood- 
vessels, followed  by  sloughing ;  beta-eucaine 
lactate  caused  swelling  and  thickening  about 
the  j)oint  of  injection,  followed  by  sloughing; 
tropacocaine  caused  swelling  and  some  thicken- 
ing, followed  by  sloughing ;  and  novocaine 
caused  no  sweUing  or  hyperaemia,  and  the  part 
remained  perfectly  normal.  From  this  it  will 
be  seen  that  novocaine  was  the  onlydrug  showing 
less  irritant  action  than  cocaine  ;  and  though  the 
strength  of  the  solutions  used  was  considerably 
in  excess  of  those  usually  employed,  yet  the 
experiments  tend  to  show  which  drugs  possess 
the  least  irritant  action.  He  found  that  all  the 
drugs  named  were  capable  of  being  combined 
with  adrenalin,  if  fresh  solutions  were  used. 

His  conclusions  summed  up  were  briefly  as 
follows  :  The  toxicity  and  anaesthetic  action 
of  novocaine  and  tropacocaine  are  about  equal, 
but  the  latter  is  more  irritant.  Comparing 
novocaine  with  beta-eucaine  lactate,  the  anaes- 
thetic action  is  about  equal,  but  while  the 
toxicity  of  eucaine  is  slightly  less,  its  irritant 
action  is  much  greater;  he  considers  that  the 
lack  of  irritation  caused  by  the  novocaine 
outweighs  its  slightly  greater  toxicity.  In 
comparing  novocaine  with  stovaine,  the  latter 
has  a  greater  anaesthetic  action,  but  its  toxicity 
is  greater  and  it  has  a  greater  irritant  action. 
On  the  whole,  therefore,  he  came  to  the  con- 
clusion that  novocaine  was  the  most  satisfactory. 
It  is  perhaps  not  safe  to  take  these  conclusions 
as  final  evidence,  as  with  experiments  on  animals, 
even  though  they  be  mammals,  the  drugs  may 
not  react  in  quite  the  same  mamier  as  on  man. 
Clinical  experience  can  be  the  only  final  guide 
as  to  which  is  the  better  drug  to  u.se. 

The  solutions  used  for  injection  have  been 
very  much  improved  by  the  recognition  of  the 
fact  that  they  must  be  capable  of  being  absorbed 
into  the  tissues  quickly  and  freely,  and  to 
attain  this  nuist  therefore  be  of  the  same 
density  as  the  fluids  of  the  body ;  in  this  way 
also  the  irritation,  pain,  and  swelling  caused  by 
injection  are  minimized.  These  results  are 
brought  about  by  making  a  solution  of  the  drug 
in  normal  saline,  or  by  adding  to  the  tablet  of  the 
drug  sufliciont  sodium  chloride  to  make  the  sola- 


669 


tion  the  same  density  as  the  blood-serum,  and  so 
facUitate  the  diffusion  of  the  solution.  Having 
the  solution  of  the  right  density  also  prevents 
change  in  the  tissue-cells,  other  than  that  which 
is  supposed  to  take  place  when  these  drugs  are 
injected.  The  drugs  when  eliminated  after 
action  are  probably  not  in  the  same  form,  some 
change  having  taken  place  \\hile  they  were  in 
conjunction  wth  the  tissue-cells.  Another 
means  of  aiding  the  rapid  absorj)tion  of  drugs 
is  by  making  the  solution  to  be  injected  slightly 
warmer  than  blood  heat,  so  that  by  the  time 
it  has  passed  through  a  cold  syringe  it  is  about 
the  temperature  of  the  blood. 

Syringe  and  Needles. — The  syringe  used  for 
dental  purposes  must  be  stronger  than  those 
used  for  hypodermic  injection,  as  the  tissues 
are  much  denser  and  a  great  deal  of  resistance 
has  often  to  be  overcome.  A  good  many  have 
been  evolved  for  this  jDurpose,  so  that  it  is 
hardly  necessary  to  describe  one  in  detail ;  it 
is  sufficient  to  say  that  it  must  be  strongly 
made,  and  capable  of  being  readily  taken  apart 
for  cleansing  purposes.  It  must  be  capable  of 
being  held  in  the  hand  with  comfort,  and  have 
finger-rests  so  that  sufficient  force  may  be 
exerted ;  it  should  be  graduated  to  show  the 
amount  of  solution  used,  and  should  be  so 
jointed  as  to  exclude  leakage  under  the  force 
exerted.  Needles  should  be  very  strong  and 
sharp-pointed,  as  unnecessary  pain  may  be 
caused  by  using  a  blunt  needle  ;  a  disc  or  stone 
run  over  the  point  ensures  a  sharp  edge. 
Needles  should  not  be  too  long,  as  they  are  more 
apt  to  bend  and  break,  nor  should  they  be  too 
short,  for  if  they  are  they  tend  rather  to  obscure 
the  view  and  render  the  injection  more  difficult ; 
I  in.  is  perhaps  the  best  length  for  most  f)urposes. 
Needles  that  can  be  attached  to  the  nozzle  are 
best,  and  it  is  better  not  to  use  them  a  second 
time.  Some  operators  prefer  a  needle  fixed  to 
the  nozzle,  but  these  require  very  careful 
sterilization  after  use.  All  needles  should  be 
immersed  in  formalin  or  some  other  antiseptic 
before  use. 

Technique  of  Injection. — The  mouth  should 
first  be  rinsed  with  an  antiseptic  solution ; 
when  the  injection  is  for  tooth  extraction,  the 
tissues  surrounding  the  tooth  should  be  further 
cleansed  and  dried,  and  a  napkin  arranged  in 
such  a  way  as  to  leave  the  tissues  exj)osed 
to  view,  and  at  the  same  time  effectually  ab- 
sorb any  of  the  solution  that  is  not  forced 
into  the  tissues.  The  point  or  points  where  the 
needle  is  to  be  introduced  should  be  painted 
with  a  solution  of  iodine,  to  prevent  the  carry- 
ing of  septic  matter  into  the  tissues.  This 
usually  also  has  the  effect  of  diminishing  the 
pain  of  inserting  the  needle,  but  if  desiral)le 
a  pledget  of  wool  soaked  in  a  strong  solution 
of  the  drug  to  be  used,  may  be  applied  to  the 


part  for  some  minutes  to  prevent  even  the 
prick  of  the  needle  being  felt ;  this  is  perhaps 
necessary  where  the  f)atient  is  at  all  nervous. 
The  amount  of  solution  to  be  injected  is  drawn 
into  the  syiinge  ^\itli  a  small  quantity  in  excess, 
to  allow  for  leakage  ;  the  piston  is  then  pressed 
down  until  a  drop  appears  on  the  end  of  the 
needle.  The  gum  where  the  needle  is  to  be 
inserted  is,  where  possible,  rendered  tense  by  the 
thumb  and  a  finger  of  the  left  hand ;  this 
makes  the  insertion  of  the  needle  easier.  The 
needle  is  then  pressed  a  little  way  into  the 
tissues,  and  at  the  same  time  force  is  exerted 
on  the  piston ;  when  a  few  minims  have  been 
injected,  a  short  time  is  allowed  for  the  absorp- 
tion of  the  solution,  pressure  being  maintained 
on  the  piston  meanwhile  to  keep  the  fluid  in. 
The  needle  is  introduced  still  further,  and  so 
on,  until  the  tissues  become  blanched.  The 
needle  is  then  witlidra\\n,  pressure  being  still 
maintained  on  the  piston.  If  the  needle  is 
not  introduced  deeply  enovigh,  a  portion  of  the 
mucous  membrane  is  raised  like  a  blister,  con- 
taining the  liquid.  When  this  happens  it  is 
best  to  withdraw  the  needle  and  insert  it  in  a 
new  position,  and  deeper.  The  first  insertion 
should  be  made  on  the  labial  aspect  of  the  tooth, 
about  midway  bet\\een  the  gum  margin  and  the 
apex  of  the  root.  The  needle  should  be  directed 
obliquely  to  the  long  axis  of  the  tooth,  and 
gradually  forced  more  deeply  into  the  tissues. 
Considerable  force  is  often  needed  to  overcome 
the  resistance  of  the  tissues  to  the  introduction 
of  the  liquid,  and  intervals  should  be  allowed 
for  its  absorption  from  time  to  time.  Care  should 
be  taken  that  the  needle  does  not  strike  the 
bone,  as  not  only  is  there  danger  of  the  needle 
breaking,  but  also  very  little  fluid  is  able  to 
escape  in  that  position. 

For  the  incisors  one  puncture  is  often 
sufficient,  but  for  a  canine  two  are  usually 
necessary,  one  on  the  labial  aspect  and  one  on 
the  palatal,  on  account  of  the  length  of  the  root. 
The  premolars  usually  require  two ;  the  upper 
molars  three,  two  on  uhe  buccal  side  and  one 
on  the  palatal.  For  the  lower  molars  two,  and 
sometimes  more,  are  necessary ;  they  are  the 
most  difficult  to  anaesthetize  successfully,  and 
the  needle  should  be  passed  in  a  direction  down- 
wards and  backwards,  and  if  possible  in  a 
straight  nozzle,  though  the  use  of  a  curved 
nozzle  is  sometimes  necessary.  Wlien  there 
are  two  or  more  injections,  care  should  be 
taken  to  introduce  the  needle  on  the  subse- 
quent occasions  within  the  area  anaesthetized 
by  a  j)revious  injection ;  and  to  enable  this 
to  be  afterwards  done,  when  introducing  the 
needle  the  first  time,  the  orifice  of  the  needle 
should  be  made  to  point  towards  the  position 
where  it  is  intended  to  make  the  second  injec- 
tion, as  the  liquid  wiU  escape  more  readily  in 


f)70 


that  dii-ection;  in  fact,  by  turning  the  needle 
round,  an  anaesthetic  zone  equal  in  all  directions 
may  be  obtained.  After  the  injections  have 
been  accomplished,  the  i^atient  should  be  asked 
to  rinse  the  mouth  again,  in  case  any  of  the 
solution  has  escaped.  The  time  to  allow  be- 
tween the  finish  of  the  injection  and  the  per- 
formance of  the  operation  varies  with  the  drug 
used,  and  also  with  the  strength  of  the 
solution.  Clinical  experience  will  soon  teach 
the  necessary  time  to  allow.  Before  actually 
performing  the  operation  it  is  as  well  to  make 
an  e.xploration  witli  a  blunt  probe,  in  order  to 
test  the  depth  of  the  anaesthesia ;  this  also, 
when  necessary,  helps  to  make  sure  of  the 
configuration  of  the  root. 

Where  the  tissues  are  in  an  inflamed  state  the 
engorged  vessels  will  not  readily  permit  of  any 
further  infiltration,  and  indeed  it  is  too  painful ; 
but  sometimes  this  may  be  overcome  by  in- 
jecting in  small  quantities  in  several  positions 
around  the  inflamed  area,  but  outside  it,  till 
gradually  an  anaesthetized  area  will  be  formed, 
which  will  reheve  most  of  the  pain.  It  is  better, 
however,  not  to  attempt  this  in  the  case  of  a 
tooth,  as  the  area  around  it  is  so  limited. 

Anaesthesia  for  Conservative  Operations 

The  injection  of  local  anaesthetics,  besides 
being  used  for  extractions  and  other  minor 
operations  in  the  mouth,  is  also  used  in  con- 
servative dentistry,  to  enable  either  a  cavity  to 
be  prei^ared,  or  a  pulp  removed,  or  other  painful 
operations  performed  on  a  tooth.  A  small  quan- 
tity of  a  weak  solution  of  one  of  the  drugs  men- 
tioned, injected  into  the  gums  surrounding  a  root 
that  is  to  be  banded  for  a  crown,  enables  this  to 
be  done  painlessly.  For  the  removal  of  a  pulf) 
in  a  single-rooted  tooth,  injections  made  in  the 
neighbourhood  of  the  apex  of  the  root,  with  the 
needle  inserted  deeply,  in  many  cases  enables 
the  pulp  to  be  removed  without  sensation.  An 
injection  made  deeply  between  two  teeth,  until 
the  needle  reaches  the  alveolar  septum  separat- 
ing them,  often  has  the  effect  of  rendering 
operations  on  these  teeth  painless  for  some 
con.siderable  time.  The  injection  into  the  gum 
around  the  neck  of  a  tooth  j)ermits  tlie  excava- 
tion and  preparation  of  cervical  cavities. 

A.  H.  Parrott  (11)  (12)  and  other  writers 
recommend  what  they  term  intra-alveolar 
injections  for  many  purposes  in  conservative 
dentistry. 

Parrott  uses  a  high-pressure  syringe,  and 
makes  a  preliminary  injection  into  the  sub- 
mucous tissue  at  a  convenient  spot,  and 
injects  a  few  minims  of  a  2  %  novocaine  solu- 
tion. He  then  changes  the  needle  used  for 
this  injection,  for  one  with  a  heavier  point 
unsharpened  and  bevelled.     With  a  round  burr 


corresponding  in  size  with  this  needle,  he  makes 
a  perforation  through  the  soft  tissues,  where 
possible  near  the  apex  of  the  tooth,  and  also 
through  the  outer  layer  of  compact  bone,  into 
the  cancellous  bone  beyond.  The  heavier 
needle  is  inserted  into  the  entrance  of  the  per- 
foration in  the  bone,  the  bevel  on  the  needle 
preventing  it  entering  far  and  also  ensuring  a 
tight  joint,  and  about  four  or  five  minims  of  the 
solution  are  injected.  The  syringe  he  uses 
works  on  the  ratchet  principle,  and  is  so  arranged 
that  for  each  movement  of  the  ratchet  only  one 
minim  is  injected.  Anaesthesia  is  produced  in 
a  few  minutes,  and  lasts  sufficiently  long  for  the 
removal  of  a  puljj  or  the  preparation  of  a  cavity. 
This  method  has  been  extensively  used  by 
many  operators,  and  successful  results  are 
reported  from  many  of  them.  It  appears, 
however,  to  many  others  as  rather  a  drastic 
operation  for  the  preparation  of  a  cavity  or 
the  removal  of  a  pulp ;  and  although  it  is  at 
present  the  surest  method  of  producing  anaes- 
thesia of  the  f)ulf)s  of  lower  molars,  perhaps  in 
the  near  future  some  modification  \\ill  be  de- 
vised, which,  while  producing  the  same  effect, 
\vill  not  necessitate  drilling  and  injecting  into 
the  bone. 

F.J.  P. 


BIBLIOGRAPHY 

(1)  Bratjn.     Die  Lokalanaesthesis. 

(2)  BuRCHABD,  H.  H.     Kirk's  American  Text-book  of 

Operative  Dentistry,  3rd  ed.,  p.  631. 

(3)  CusHNEY.     Text-book  of  Pharmacology. 

(4)  FiscHEB,   G.     Technique   of  Injection.     Deutsche 

Zahnarztliche  IVochenschrift.  Trans.  Dental 
Cosmos,    1909,  Vol.   LI,   p.    1341. 

(5)  Gabell  and  Austen.    Materia  Medica  for  Dentists, 

p.  89. 

(6)  Hey,  S.  D.     Local  Anaesthesia  and  Methods  of 

producing  it.  Brit.  Dent.  Jour.,  1910,  Vol. 
XXXI,  p.  405. 

(7)  HowKiNS,  C.  H.     Local  Anaesthesia  in  Dentistry. 

Brit.  Dent.  .Jour.,  1907,  Vol.  XXVIII,  p.   1013. 

(8)  Le  Brocq,  C.  N.     Substitutes  for  Cocaine.     Brit. 

Med.  Jour.,  1909.     Dental  ReconI,  Aug.  1909. 

(9)  Luke  and  Ross.     Anaesthesia  in  Dental  Surgery. 

(10)  Pare,  J.  W.     A  New  Local  Anaesthetic.     Trans. 

Odont.  Soc.,  190B-7,  Vol.  XXXIX,  p.  120. 

(11)  Parrott,  A.  H.     Injection  Anaesthesia  in  Con- 

servative Dentistry.  Brit.  Dent.  Jour.,  1910, 
Vol.  X.XXl,  p.  1201.  Dental  Record,  1910, 
Vol.  XXX,  p.  181. 

(12)  Parrott,  A.  H.     Proc.  Roy.  Soc.  of  Med.  {Odont. 

Sec),  1912. 

(13)  Prinz,  Hermann.     Johnson's  Operative  Dentistry, 

Chap.  XXV,  p.  385. 

(14)  Reclus,  p.     Brit.  Dent.  Jour.,  1906,  Vol.  XXVII, 

pp.  170,  225. 

(15)  Sauvez,  E.     A  Study  of  the  Best  Means  of  Local 

Anaesthesia  for  Extraction  of  Teeth.  Brit.  Dent. 
Jour.,  1905,  Vol.  XXVI,  pp.  373,  445.  Dis- 
cussion, 679. 

(16)  Struthers.     Local  Anaesthetics. 

(17)  White,    Hale.     Materia    Medica    and    Pharma- 

cology, p.  99. 


CHAPTEll    XLIl 


ALVEOLAR   ABSCESS 


Alveolar  abscess  occurs  in  connection  with 
any  tooth,  deciduous  or  permanent.  The 
tooth,  or  particular  root,  with  which  it  is  con- 
nected is  always  septic  as  a  result  of  death  of 
the  pulp — a  sequel  generally  of  caries,  sometimes 
of  violence.  A  few  cases  of  alveolar  abscess 
occurring  in  connection  with  living  teeth  are 
recorded  in  dental  literature,  but  these  should 
probably  be  classed  with  paradental  abscess  of 
pyorrhoea.  Alveolar  abscess  may  be  expected 
at  any  time,  from  a  few  months  after  eruption 
of  the  first  deciduous  incisor  to  the  close  of 
life.  Six  months  suffices  for  caries  to  destroy 
the  crown  of  any  young  tooth,  deciduous  or 
permanent,  so  that  the  disease  may  be  found  in 
connection  with  any  tooth  at  any  time  from 
six  months  after  its  eruption.  The  particular 
incidence  of  alveolar  abscess  follows  dental 
caries :  the  simplest  teeth — the  lower  six  front 
teeth,  deciduous  or  permanent — are  the  least 
frequently  attacked ;  the  rest  may  for  practical 
purposes  be  classed  together  as  equally  liable. 
General  health  has  little  practical  influence, 
but  as  with  most  diseases,  lowered  resistance 
may  be  the  precipitating  cause ;  in  general, 
however,  the  dose  and  virulence  of  the  microbic 
infection  are  sufficient  to  overcome  the  healthi- 
est resistance.  As  with  abscess  elsewhere,  pus 
formation  is  generally  definitely  due  to  germ 
infection.  The  organisms  incriminated  include 
staphylococcus  aureus  and  albus,  streptococcus 
longus,  and  di25lococcus  pneumoniae. 

In  some  cases,  both  acute  and  chronic  or 
quiet,  but  always  unopened  cases,  no  organisms 
have  been  found.  This  may  be  due  to  the 
fact  that  the  germ  has  destroyed  itself  by  the 
products  of  its  own  activity. 

COURSE    AND    PATHOLOGY    OF    ALVEOLAR 
ABSCESS 

Most  commonly  the  pulp  of  the  tooth  dies  as 
a  sequel  of  germ  infection  after  exposure  by 
caries ;  in  some  cases  as  the  result  of  infection 
through  the  yet  hard  dentine  via  the  dentinal 
tubules.  When  the  pulp  dies  as  a  result  of 
violence,  germ  infection  probably  takes  place 
through  a  crack  in  the  tooth,  or  along  the 
injured  periodontal  membrane. 

In  the  case  of  a  two-  or  three -rooted  tooth, 
abscess  formation  may  begin  at  the  apex  of  one 


or  every  root,  or  there  may  be  a  live  pulp  strand 
in  one  root  and  an  abscess  comiected  with  the 
dead  pulp  in  another.  In  a  few  cases  part  of 
the  pulp  itself  has  been  found  alive  as  well  as 
the  nerve  of  one  root,  while  there  has  been 
abscess  formation  at  the  apex  of  the  root  whose 
nerve  and  blood  vessels  were  distributed  in  the 
gangrenous  portion  of  the  pulp.  Abscess  forma- 
tion begins  by  infection  of  the  peri-apical  tissue 
through    the    apical    foramen ;      germs     may 

(1)  spread  through  by  growth,  (2)  be  forced 
through  by  pressure  of  gaseous  products  of 
putrefaction,  or  (3)  be  forced  through  by  mani- 
pulation. 

At  first  there  is  only  inflammation  of  the 
periodontal  membrane  and  bone  surrounding 
the  apex.  In  acute  cases  this  soon  gives  way 
to  suppuration  and  destruction  of  bone  tissue, 
forming  a  central  l)one  abscess.  In  cases  that 
are  chronic  from  the  beginning,  there  is  a  slow 
rarefying  osteitis,  leading  to  considerable  forma- 
tion of  granulation  tissue,  for  some  time  before 
pus  formation  commences.  The  bone  is  de- 
stroyed by  molecular  necrosis ;  very  rarely  is 
there  any  tangible  necrotic  fragment.  In  a 
few  cases  the  pus  finds  a  vent  through  the  canal 
of  the  root ;  in  a  few  others  along  the  side  of 
the  root,  between  it  and  the  bone  of  the  socket ; 
most  frequently  the  abscess  enlarges  in  the 
direction  of  least  resistance  and  eventually 
perforates  the  hard  outer  bone  casing.  Most 
frequently  this  perforation  occurs  through  the 
outer  side,  even  when  the  abscess  arises  from 
the  palatal  root  of  an  upjoer  tooth ;  this 
may  be  due  in  j^art  to  the  direction  of  the 
leash  of  vessels  and  nerves  entering  the  root 
foramen,  and  in  part  to  the  density  of  the  hard 
palate.  In  the  maxilla  the  pus  may  also 
perforate  in  the  following  positions  :  (1)  The 
palatal  aspect ;  more  usually  such  an  abscess 
arises  from  the  lateral  incisor  or  first  molar, 
but    may    arise    from   any    one    of    the    teeth. 

(2)  The  nasal  floor ;  arising  from  an  incisor, 
canine,  or  a  premolar,  and  possibly  the  palatal 
root  of  a  first  molar.  (3)  The  floor  of  the 
maxillary  sinus  ;  arising  from  any  of  the  cheek 
teeth,  i.  e.  premolars  and  molars.  In  the 
mandible  exit  on  the  lingual  side  is  rare. 

After  perforating  the  outer  bone  case  the  pus 
strips  up  the  periosteum  to  a  greater  or  less 
extent,  forming  a  sub-periosteal  abscess,  and  in 


671 


672 


general,  finding  the  least  resistance  in  the 
direction  of  the  alveolar  buccal  sulcus  (vesti- 
l)ulum  oris),  perforates  the  alveolar  muco- 
periosteum — hence  the  use  of  the  term  "  alveolar 
abscess  ".  The  point  of  exit  through  the  muco- 
periosteum  is  very  seldom  opposite  that  through 
the  bone. 

Fascial  or  muscular  attachment  to  the  bone — 
cervical  fascia,  buccinator — may  prevent  sub- 
periosteal spread  in  the  vestibular  direction, 
especially  in  the  case  of  long -rooted  teeth ;  the 
pus  on  perforating  the  periosteum  then  forms 
an  interstitial  abscess  among  the  fascial  layers 
of  the  face  or  neck,  and  issuing  again  from 
beneath  the  fascia  by  the  same  process -of 
destroying  the  tissues  in  the  line  of  least  resist- 
ance, may  form  a  sub-cutaneous  abscess  before 
eventually  opening  on  the  surface.  Thus  the 
possible  "stages  of  an  alveolar  abscess  are  : 
(1)  central  abscess  of  bone,  (2)  sub-periosteal 
abscess,  (3)  exit  into  mouth  ;  or — 

(1)  central  abscess  of  bone, 

(2)  sub-periosteal  abscess, 

(3)  interstitial  abscess, 

(4)  sub-cutaneous  abscess, 

(5)  exit  through  the  skin. 

(2)  (3)  and  (4)  will  only  be  distinguishable 
from  one  another  in  the  less  acute  cases. 

Alveolar  abscess  may  be  acute  or  chronic 
from  the  beginning ;  chromcity  frequently 
follows  on  an  acute  commencement,  and  an 
acute  phase  may  complicate  a  chronic  case. 
Wlien  dose  and  virulence  are  low  the  process 
will  be  chronic  from  the  begimiing,  and  "  point- 
ing "  will  be  correspondingly  delayed  ;  otherwise 
the  clinical  symptoms  are  acute  in  inverse  ratio 
with  drainage.  \Vlien  an  acute  or  chronic 
abscess  bursts,  unless  the  cause  is  removed  a 
fistula  or  discharging  sinus  forms ;  so  long  as 
this  is  patent  the  course  of  the  abscess  will  be 
chronic,  but  if  the  fistula  is  blocked  in  any  part 
of  its  course,  as  soon  as  pus  has  collected 
in  sufficient  quantity  to  cause  tension,  i.  e. 
to  determine  absorption,  the  course  becomes 
acute. 

The  microscopic  appearances  of  the  tissues 
round  an  acute  or  chronic  alveolar  abscess  differ 
in  no  way  from  those  found  in  inflammatory 
processes  of  bone  or  soft  tissue  elsewhere.  In 
the  most  chronic  cases  of  peri-apical  or  peri- 
radicular  infection,  there  is  a  free  formation  of 
interstitial  granulation  tissue  replacing  the  bone 
and  almost  entirely  obliteratmg  the  periodontal 
membrane.  In  parts  this  granulation  tissue 
may  break  down  into  pus,  forming  what  is  at 
first  a  minute,  almost  miliary,  abscess.  On 
extraction,  such  an  abscess  may  be  brought  out 
entire  in  a  mass  of  granulation  tissue  adherent 
to  the  root.     This  is  the  only  sense  in  which  a 


"pus  sac  "  is  ever  found  adherent  to  a  root; 
what  is  generally  so  described  is  a  small  dental 
cyst. 

CLINICAL   COURSE    AND    SIGNS    OF    ACUTE 
ALVEOLAR    ABSCESS 

The  first  stage,  infection  of  the  periodontal 
membrane  and  bone  round  the  apex,  causes  a 
tenderness  of  the  tooth,  at  first  relieved  by 
pressure,  but  rapidly  increasing,  and  soon 
followed  by  rising  of  the  tooth  in  its  socket,  so 
that  biting  becomes  painful,  and  by  tenderness 
of  the  overlying  bone  and  gum.  The  pain,  at 
first  dull  and  shght,  rapidly  becomes  severe  and 
throbbing,  increased  by  each  pulse -wave,  and 
continuous,  but  remains  local,  whereby  it  is  in 
general  differentiated  from  the  pain  of  an 
inflamed  or  irritated  pulp,  which  is  often 
referred  or  neuralgic  ;  in  some  cases  an  abscess 
as  it  forms  may  involve  a  mmute  nerve-trunk 
and  give  rise,  especially  in  the  early  stage,  to  a 
true  neuralgia  (see  also  involvement  of  inferior 
maxUlary  trunk  later).  The  severity  of  the 
pain  is  due  to  tension  of  the  inflammatory  exu- 
dation within  the  unyielding  bone,  and  marks 
the  inception  of  pus  formation.  There  is  now 
an  acute  central  abscess  of  the  bone.  Within 
a  few  hours  there  is  some  swelling  of  the  over- 
lying soft  tissues — a  slight  swollen  face.  In 
from  twelve  to  twenty-four  hours  from  the  be- 
ginning there  is  a  sudden  relief  of  acute  pain, 
followed  by  rapid  increase  in  the  swelling  of 
the  soft  tissues.  This  marks  the  relief  of  tension 
by  perforation  of  the  outer  plate  of  the  bone 
and  the  formation  of  a  sub-periosteal  collection 
of  pus.  In  proportion  to  the  amount  of  pus 
the  swelling  of  the  soft  tissues  is  extreme ;  hence 
fluctuation  is  a  sign  that  is  not  to  be  expected. 
This  is  due  to  the  looseness  of  the  cellular  tissues 
of  the  face,  which  allows  oedema  to  spread  even 
to  the  eyelids.  The  soft  tissues,  cellular  and 
muscular,  are  now  mfiltrated  with  inflammatory 
exudation,  and  tender  on  movement ;  hence 
difficulty  of  opening  the  mouth  is  a  very  usual 
symptom  of  alveolar  abscess.  Generally  the 
abscess  points  in  the  mouth,  on  the  outer  side 
of  the  alveolus,  directed  by  the  attachment  of 
the  buccinator.  Not  infrequently  pus  perforates 
the  periosteum  beyond  the  attachment  of  the 
buccinator,  and  then  points  externally.  A 
second  lower  deciduous  molar  or  a  first  lower 
permanent  molar  is  a  common  source  of  such 
an  abscess,  but  in  proportion  to  its  frequency 
abscess  of  a  lower  permanent  incisor  is  most 
often  followed  by  external  evacuation.  When 
the  pus  points  externally  on  the  outer  side  of 
the  mandible,  it  is  superficial  to  the  deep  cervical 
fascia,  and  the  disease  runs  a  more  rajiid  and 
easy  course  than  when  the  pus  issues  below  the 
mandible  and  so  gets  beneath  the  deep  cervical 


673 


fascia.  Pus  finding  its  way  externally  towards 
the  skin  will  give  rise  to  the  usual  symptoms 
of  inflammation  and  abscess — redness,  swelling, 
local  lieat,  and  pain,  followed  by  fluctuation. 
If  poulticed  tiU  it  breaks,  or  allowed  to  burst 
naturally,  the  abscess  will  degenerate  into  a 
discharging  sinus,  and  later,  when  healing  occurs, 
there  wiU  be  a  puckered  scar  adherent  to  the 
bone.  There  may  be  an  accompanying  glan- 
dular abscess.  Pus  (usually  from  a  third  lower 
molar)  finding  its  way  beneath  the  deep  cervical 
fascia  wiU  give  rise  to  a  hard,  brawny,  tender, 
painful  swelUng  below  the  mandible,  finding 
but  little  relief  from  tension  on  its  exit  from  the 
bone ;  some  days  must  elapse  before  the  tissues 
are  sufficiently  softened  to  allow  the  abscess  to 
point.  In  these  cases  there  is  a  persistent 
raising  of  the  general  temperature  of  one  or 
two  degrees,  and  enlargement  of  lymphatic 
glands,  which  may  run  on  to  suppuration, 
giving  rise  to  a  second  and  distinct  collection 
of  pus ;  but  both  suppurating  foci  will  be 
enclosed  in  one  uniform  and  tense  inflammatory 
swelling.  A  rise  of  temperature  and  an  enlarge- 
ment of  lymphatic  glands  probably  occur  in  all 
cases  of  pus  formation,  but  owing  to  the  rapidity 
of  the  process  are  of  such  a  transitory  nature  as 
to  escape  detection. 

CLINICAL    COURSE    AND   SIGNS    OF    A 
CHRONIC    ABSCESS 

These  are  often  limited  to  a  discharging  sinus, 
with  perhaps  some  inflammatory  redness  and 
swelling  of  overlying  gum.  In  the  most  chronic 
cases  it  may  be  years  before  a  sinus  appears. 
Opposite  the  apex  of  the  root  of  the  affected 
tooth  a  small  tender  inflammatory  nodule  of 
the  periosteum  is  often  found.  Occasionally, 
sometimes  at  regular  intervals,  when  drainage 
faUs  after  once  becoming  established,  there  is 
a  more  acute  phase.  In  the  mandible,  deposi- 
tion of  new  periosteal  bone  is  to  be  expected, 
but  not  in  the  maxilla.  Tangible  glandular 
swellings  may  be  found,  but  quite  generally  the 
glandular  swelling  escapes  notice. 

Diagnosis  of  Acute  Alveolar  Abscess. — This  is 
to  be  made  from  (I)  the  existence  of  a  septic 
tooth,  and  (2)  local  acute  inflammatory  symp- 
toms ;  and  in  the  early  stage  before  swelling, 
by  acute  tenderness  of  the  tooth  and  a  history 
of  local  pain  and  tenderness  gradually  increasing 
from  discomfort  to  agony.  The  inflamed  tissues 
are  very  sensitive  to  sudden  changes  of  tempera- 
ture. Difficulty  arises  where  the  abscess  is  due 
to  a  buried  root  (in  this  case  a  radiograph  will 
assist  diagnosis) ;  or  when  inflammatory  trouble 
of  the  neighbouring  part  (c.  g.  maxillary  sinus, 
nasal  duct,  necrosis  of  nasal  process  of  maxillary 
bone,  superficial  abscess,  or  deep  acne  abscess) 
encroaches  on  the  area  usually  occupied  by  a 
22 


dental  swelling.  In  general  the  most  tender 
and  prominent  part  of  the  swelling  is  opposite 
the  offending  tooth.  Fluctuation  is  not  to  be 
expected  in  the  acute  stage,  and  the  amount  of 
pus  is  very  smaU  compared  with  the  swelling  of 
the  soft  parts.  If  the  sub-periosteal  stage  is 
prolonged,  fluctuation  will  become  evident. 

Diagnosis  of  Chronic  Abscess. — A  chronic 
alveolar  abscess  very  commonly  escapes  notice 
till  the  patient's  attention  is  called  to  a  dis- 
charging sinus.  In  the  vestibuhim  oris  the  end 
of  the  sinus  is  often  drawn  out  into  a  long 
nipple-like  process.  A  chronic  discharging  sinus 
of  the  face  or  neck,  or  even  further  afield,  should 
always  lead  to  a  careful  examination  of  the 
teeth.  Other  clinical  signs  are  frequently 
absent,  but  there  is  generally  some  alveolar 
tenderness  and  some  slight  sweUing  and  blood 
injection  of  the  surrounding  gum,  obscuring 
the  so-called  health-line  of  the  gums,  i.  e.  a  line 
marking  the  limit  of  the  attachment  of  the 
muco-periosteum  to  the  bone,  beyond  which  on 
the  cheek  side  the  mucous  membrane  is  free 
and  shows  greater  vascularity  than  where  it 
is  intimately  bound  down  to  the  periosteum. 
In  inflammatory  conditions  of  the  gum  this 
contrast  is  lost  by  increased  vascularity  of  the 
gum.  In  the  mandible  a  chronic  alveolar 
abscess  may  be  accompanied  by  considerable 
bony  swelling  and  actual  deposition  of  new 
periosteal  bone.  In  some  cases  where  there 
has  been  no  sinus  formation  there  is  a  hard 
limpet-like  swelling  on  the  bone  due  to  periosteal 
new  bone  capjjed  by  inflamed  periosteum.  Such 
cases  have  a  subacute  history  of  six  weeks  to 
two  months.  In  more  chronic  cases  the  bone 
swelling  is  more  diffuse,  and  may  be  apparent 
on  all  sides.  A  sujjpurating  dental  cyst  may 
be  mistaken  for  an  alveolar  abscess.  Evidence 
of  true  tumour  growth,  thimied  and  expanded 
bone-shell,  negatives  simple  abscess.  Clinically 
it  is  difficult  or  impossible  to  distinguish  the 
early  stage  of  a  dental  cyst  from  chronic  abscess 
before  sinus  formation.  In  the  mandible  it  is 
impossible,  smce  there  will  be  bone  swelling  in 
both  cases,  and  the  early  stage  of  a  dental  cyst 
may  be  accompanied  by  signs  of  inflammation 
due  to  the  periodontitis  that  originally  started 
its  growth.  In  the  maxilla  after  early  life  a 
bone  swelling  indicates  tnie  tumour  growth,  the 
periosteum  of  the  maxilla  early  ceasing  to  deposit 
inflammatory  new  bone. 

A  sinus  opening  remote  from  the  originating 
tooth  is  generally  the  pomt  of  exit  of  a  chronic 
abscess — at  least  by  the  time  the  opening  is 
recognized  the  symptoms  have  ceased  to  be 
acute.  Remote  openings  may  be  found  (1)  in 
the  floor  of  the  nose  ;  (2)  on  the  back  of  the  soft 
palate  (rare,  and  recorded  as  due  to  an  incisor) ; 
(3)  on  the  cheek  over  the  maxilla  or  malar  bone, 
and  in  these  cases  pus  is  very  liable  to  track  in 


674 


different  directions,  and  besides  forming  an 
external  opening  it  is  liable  to  form  several 
blind  pockets  (healing  is  slow  and  the  chronicity 
of  the  process  may  suggest  streptothrix  infec- 
tion) ;  (4)  outside  or  under  the  mandible ; 
(5)  along  the  neck  as  far  down  as  the  clavicle, 
limited  then  by  the  attachment  of  the  deep 
cervical  fascia. 

Generally  a  probe  can  be  passed  from  the 
point  of  exit  to  the  tooth  of  origin,  but  some- 
times the  remote  abscess  is  entirely  cut  off  from 
the  source  of  the  trouble.  In  these  chronic 
cases  the  tooth  itself  is  generally  free  frorn  pain 
and  tenderness  owing  to  freedom  of  drainage. 
A  pulp  that  has  died  painlessly  as  the  result 
of  infection  via  the  dentinal  tubules,  under  only 
a  small  filHng,  may  initiate  a  chronic,  practically 
painless,  suppurative  process,  eventuating  in 
remote  sinus  formation. 

RARER  FORMS  OF  CHRONIC  ABSCESS 

Sometimes  a  quiet  abscess,  generally  due  to  an 
incisor  or  canine,  hollows  out  the  entire  body  of 
the  maxilla  of  one  side  (the  process  appears  to 
be  unable  to  pass  the  suture-lme)  producing  no 
clinical  symptoms  till  a  small  sinus  forms, 
perhaps  years  after  its  inception.  Such  an 
abscess  may  be  found  at  the  root  of  a  tooth  that 
has  been  left  untreated  after  traumatic  death 
of  the  pulp,  or  in  slow  pyorrhoea,  as  well  as  in 
connection  with  teeth  dead  as  the  result  of 
caries.  It  may  be  mistaken  for  a  suppurating 
maxillary  sinus  or  cyst. 

Residual  Abscess. — The  minutest  apex  of  a 
tooth  left  in  at  the  time  of  extraction,  a  minute 
central  necrosis,  or  a  residual  germ  infection, 
may,  years  afterwards,  cause  an  abscess. 
Hence  it  becomes  important  to  note  every 
fractured  root  at  the  time  of  extraction.  Such 
an  abscess  may  be  acute,  or  may  be  chronic  or 
subacute.  Wlien  chronic  or  subacute,  it  gives 
rise  to  the  same  symptoms  as  chronic  central 
abscess  of  bone  in  other  parts,  i.  e.  intermittent 
pain  and  tenderness,  worse  at  night,  shght 
swelling  of  soft  parts  and  of  lymphatic  glands 
similarly  intermittent,  and  in  the  mandible 
some  deposition  of  the  periosteal  bone.  Li  the 
more  acute  cases  the  intermissions  of  pain  are 
sometimes  so  regular  as  to  suggest  malaria. 

A  chronic  abscess  of  the  mandible  may  in- 
volve the  inferior  alveolar  nerve  and  set  up 
most  acute  neuralgia- — such  an  occurrence  has 
not  been  recorded  in  the  case  of  an  acute 
abscess. 

Injection  Abscess. — Sub -periosteal  or  inter- 
stitial abscess  may  follow  the  use  of  local  injec- 
tions, as  the  result  of  infected  needle  or  fluid, 
or  of  injecting  into  or  through  an  infected  area, 
when  fluid  under  pressure  or  the  passage  of  the 
needle  may  cause  a  diffusion  of  the  infecting 


virus  beyond  the  area  that  has  been  protected 
by  inflammatory  reaction. 

TREATMENT 

In  general  terms,  remove  the  cause  and 
secure  drainage.  This  is  best  done  by  extrac- 
tion ;  a  tooth  may  be  extracted  at  any  stage 
of  the  process ;  there  is  no  reason  for  waiting 
until  tlie  inflammation  is  gone.  If  there  is 
difficulty  in  opening  the  mouth,  gentle  per- 
sistent force  will  overcome  it,  and  a  general 
anaesthetic  may  be  used  to  obviate  unconscious 
resistance.  In  aU  inflammatory  cases  local 
anaesthetics  will  be  worse  than  useless,  unless 
regional  anaesthesia  can  be  secured  by  injection 
behind  the  lesion.  After  extraction  in  the  case 
of  an  acute  abscess  syringing  is  seldom  necessary. 
With  a  chronic  abscess  opening  externally,  a 
silver  probe  should,  if  possible,  be  passed  till  it 
finds  the  opening  in  the  jaw,  and  the  tract  well 
syringed  to  make  sure  that  there  is  no  inter- 
mediate collection  of  pus  left. 

To  syringe — 


B 


Acid  Carbol.  liq. 
Sod.  Bicarb 
Aquam  ad  . 
M.  ft.  lot. 


"l  vj. 
gr.  X. 

5  J- 


When  it  is  desired  to  save  the  tooth,  treatment 
depends  on  the  stage  at  which  the  abscess 
presents  itself.  In  the  early  stage  of  an  acute 
abscess,  before  pus  has  made  exit  from  the  bone, 
the  tooth  is  too  tender  to  admit  of  much 
manipulation.  With  a  sharp  instrument  worked 
on  a  smooth-running  engine,  a  hole  may  be 
drilled  vertically  through  the  crown  to  the  pulp- 
cavity,  or  a  root-canal  may  be  partly  reamed  out, 
the  tooth  being  meanwhile  steadied  in  such  a 
way  as  to  afford  aU  possible  reUef  from  pressure. 
The  pulp-cavity  may  be  syringed,  and  perhaps 
the  abscess  aspirated  by  means  of  a  hypodermic 
syringe  thrust  into  a  root-canal,  after  which  the 
tooth  may  be  dried  and  some  antiseptic  intro- 
duced, and  if  feasible  gently  pumped  up  the 
root-canal.  The  tooth  may  eventually  be  left 
open  to  secure  drainage  and  to  relieve  any 
pressure  that  may  be  caused  by  gaseous  pro- 
ducts of  decomposition ;  or  paraform  paste 
(paraform  and  tricresol)  may  be  lightly  sealed 
in.  Paraform  is  said  slowly  to  liberate  formaUn 
vapour,  which  penetrates  and  exerts  its  anti- 
septic action ;  but  the  success  of  early  treatment 
probably  depends  far  more  on  the  establishment 
of  drainage  at  an  early  stage  than  on  any 
particular  ding  used ;  indeed,  the  success  of 
rhizodontrophy — drilling  a  hole  laterally  through 
the  neck  of  the  tooth  into  the  pulp-chamber — 
depended  entirely  on  early  drainage  and  relief 
of  gas  pressure. 


675 


111  case  this  treatment  fails  to  afford  relief, 
the  patient  may  be  given  the  following — 


B 


Tinct.  Opii.  . 
Aqiiam  ad 
M.  ft.  mist. 


5J- 


IV. 


Sig. — One  ounce  %\hen  needed,  followed 
in  half  an  hour  by  anotlier  ounce  if  there 
is  no  relief.  All  four  doses  may  be  taken 
during  the  night. 

Opium  is  the  only  reliable  drug  for  the  relief 
of  pain.  Hot  fomentations  may  give  some 
reUef ,  used  both  in  the  mouth  and  over  the  face. 
In  these  cases  capsicum  plasters  and  strong 
iodine  liniment  probably  owe  their  reputation 
to  the  accident  of  being  used  shortly  before 
natural  relief  occurs.  In  some  cases  it  may  be 
possible  by  cutting  down  on  the  bone  and 
perforating  it  to  reach  the  pus,  but  even  with 
a  single-rooted  tooth  the  success  of  this  operation 
is  uncertain,  and  if  early  treatment  ina  the 
crown  fails,  the  dentist  will  generally  have  to 
wait  till  the  pus  makes  its  own  way  out,  trusting 
to  opium  for  relief  of  pain.  To  perforate  the 
alveolus  a  small  incision  is  to  be  made  on  to 
the  bone,  and  with  a  sharp  spear-pointed  drill 
on  the  dental  engine,  the  alveolus  is  jjerforated 
at  a  spot  as  near  as  possible  to  the  root-apex. 
An  anaesthetic  is  desirable,  but  if  not  available, 
it  may  be  possible  to  effect  an  entrance  in  the 
following  way.  Apply  to  one  spot  of  the  mucous 
membrane  a  very  little  pure  carbolic  acid  ;  wait 
till  the  spot  is  well  whitened  and  then  scrape 
away  the  dead  tissue  ;  repeat  this  till  the  bone ' 
is  reached ;  then  proceed  similarly,  but  use  a 
rose-head  burr  in  the  engine.  A  serrated  gold- 
plugger  may  be  used  both  to  apply  the  carbolic 
acid  to  the  gum,  and  by  rotating  it  to  scrape 
away  the  dead  tissue. 

When  relief  of  pain  has  occurred,  tliat  is, 
when  the  pus  has  perforated  the  bone,  it  may 
be  well,  in  order  both  to  expedite  matters  and 
to  secure  evacuation  into  the  mouth,  to  cut  on 
to  the  pus.  The  incision  should  be  made  doAni 
to  the  alveolar  bone  opposite  the  most  prominent 
part  of  the  s-nelling ;  if  pus  is  not  found  it 
should  be  sought  for  with  a  director,  the  point 
of  which  is  kept  in  contact  wth  the  bone.  In 
opening  a  palatal  abscess  the  position  of  the 
posterior  palatine  artery  at  the  base  of  the 
alveolus  should  be  remembered :  the  artery 
may  be  stripped  up  with  the  muco-periosteum 
by  the  pus.  In  dealing  with  abscesses  that  are 
pointing  on  the  face  a  small  external  incision 
should  be  made  early  :  time  is  not  to  be  wasted 
in  trying  to  draw  the  abscess  to  a  point  in  the 
mouth.  An  early  incision  need  be  but  a  punc- 
ture, through  which  the  abscess  may  be  gently 
evacuated  and  syringed,  and  which  will  eventu- 


ally leave  practically  no  scar ;  delay  wiU  result 
I  in  much  destruction  of  tissue  and  a  j)uckered 
scar  adherent  to  the  bone.  In  these  cases  the 
1  position  of  the  facial  artery  passing  over  the  man- 
dible at  the  anterior  edge  of  the  attachment  of 
the  masseter  muscle  must  be  borne  in  mind. 

For  treatment  of  septic  roots  see  Chapter 
XXVII,  pp.  471  et.  seq. 

Wlien  the  tooth  is  to  be  saved,  treatment  of 
a  chronic  abscess  is  best  carried  out  by  securing 
!  a  free  flush  through  the  root-canal  and  out  by 
the  alveolus.  Where  there  is  no  fistula  already 
existing,  an  attempt  may  first  be  made  to  clear 
out  the  abscess  via  the  root-canal  by  aspiration, 
antiseptic  solution  being  injected  and  with- 
drawn by  means  of  a  hypodermic  syringe,  and 
the  root  thoroughly  treated ;  but  generally  it 
will  be  found  necessary  to  make  an  external 
opening,  which  may  often  be  done  under 
novocaine  anaesthesia.  After  establishment  of 
an  external  sinus,  a  weak  alkaline  carbolic 
lotion  is  to  be  forcibly  syringed  through  from 
the  root-canal  to  the  external  opening  every 
day  till  pus  formation  ceases.  Generally  this 
occurs  in  three  days.  In  difficult  cases  fluid 
may  be  made  to  flow  through  under  pressure 
by  packing  round  the  nozzle  of  the  syringe  with 
gutta-percha.  Before  syringing  pass  a  fine 
probe  as  far  as  jJossible  through  both  root  and 
external  opening- — a  small  flake  of  coagulated 
lymph  may  entirely  obstruct  the  flow.  Creosote 
used  in  tliis  manner,  either  by  pumping  or 
syringing  under  pressure  till  it  appears  on  the 
gum,  sometimes  effects  a  cure  in  one  or  two 
sittings. 

Often  the  roots  are  curved,  or  blocked  by 
secondary  dentine,  or  the  canal  is  too  minute 
to  follow.  The  introduction  of  10  %  suljshuric 
acid  is  said  to  be  useful  in  the  two  last  cases 
in  assisting  to  open  up  the  root-canal,  but  in 
the  absence  of  stereoscopic  radiographs  the 
diagnosis  is  at  best  but  guess-work.  Before 
using  solvent  agents,  after  reaming  out  the  root 
antiseptic  dressings  should  be  applied  for  a 
week.  Unless  the  drill  is  felt  easOy  to  follow 
the  root-canal  there  is  no  sure  guide  to  its  course, 
and  when  a  root  is  perforated  laterally  loss  of 
the  tooth  is  certain.  The  abscess  meanwhile 
must  be  syringed  from  outside.  These  cases 
are  sometimes  treated  by  cutting  down  on  to 
the  root  through  the  alveolus  and  excising  its 
terminal  jiart.  Laying  the  abscess  cavity  open 
from  the  buccal  side,  and  plugging  lightly  till 
it  heals  from  the  bottom,  is  an  equally  successful 
method  of  treatment,  and  both  measures 
probably  depend  on  the  establishment  of 
efficient  drainage.  In  the  writer's  experience 
these  operations  are  seldom  necessary. 

Abscess  of  a  third  lo^^•er  molar  (wisdom  tooth) 
has  characters  that  need  special  mention  (see 
Chapter  II) .    These  it  owes  to  its  situation,  which 


676 


renders  stagnation  round  the  partly  erupted 
tooth  almost  mevitable,  and  to  the  tendency  that 
pus  from  a  radicular  abscess  of  the  tooth  has 
to  get  beneath  the  deep  cervical  fascia.  Owing 
to  want  of  space  the  third  lower  molar  finds 
great  difficulty  in  reaching  full  eruption.  This 
gives  stagnant  germs  time  to  infect  the  partly 
obliterated  tooth-sac,  and  an  abscess  round  the 
partly  erupted  crown  results.  The  existence 
of  "pyorrhoea  alveolaris  "  greatly  increases  the 
probability  of  such  a  stagnation  abscess.  An 
abscess  following  on  caries  of  the  third  molar 
frequently  finds  its  exit  from  the  bone  below 
the  attachment  of  the  deep  cervical  fascia, 
giving  rise  to  a  tense  brawny  swelling  and  pro- 
tracted suffering,  and  perhaps  tracking  far  down 
the  neck  before  evacuation  occurs.  Both  these 
forms  of  abscess  are  accompanied  by  more  or  less 
inability  to  open  the  mouth  owing  to  tenderness, 
which  may  induce  reflex  protective  spasm  of 
the  muscles  (an  inflamed  part  is  instinctively 
kept  at  rest),  and  to  inflammatory  infiltration, 
which  mechanically  interferes  with  movement. 
If  the  abscess  becomes  subacute  by  reason  of 
partial  drainage,  trismus  may  last  for  weeks. 
Cellulitis  of  the  neck  and  throat,  or  tonsillar 
abscess,  not  infrequently  follows  this  form  of 
dental  abscess,  the  original  cause  remaining 
undiscovered  owing  to  the  difficulties  of  clinical 
examination.  A  radiograph  should  always 
be  taken  in  doubtful  cases.  Pus  in  the  mouth, 
often  seen  as  a  tliin  film  spread  over  the  gum 
in  the  neighbourhood  of  the  third  lower  molar ; 
inflammatory  swelling  of  the  gum  and  surround- 
ing tissues — cheek  and  fauces  ;  inflammatory 
swelling  and  pointing  of  pus  externally  near  the 
angle  of  the  jaw  or  lower  down  the  neck,  should 
raise  a  suspicion  of  a  third  molar  as  the  prime 
cause. 

As  far  as  the  teeth  are  concerned  extraction 
is  the  best  treatment.  This  may  need  the  use 
of  a  bone  chisel  and  mallet.  Before  attempting 
an  operation,  pus  must  be  evacuated  and  the 
parts  rendered  as  aseptic  as  possible.  The 
bone  should  be  laid  bare  and  gently  chiselled 
away  from  the  outer  and  upper  side  of  the  tooth. 
Stereoscopic  radiographs  will  give  valuable 
information  as  to  the  position  of  the  tooth, 
which  generally  lies  with  its  coronal  surface 
forward.  No  great  force  should  be  exerted 
either  \nth  forceps  or  elevator,  since  injury  to 
the  bone  in  so  undrainable  a  situation  is  gener- 
ally followed  by  necrosis.  Syringing  will  have 
to  be  practised  for  six  weeks  or  more  after  the 
operation. 

SEQUELAE  OF  ALVEOLAR  ABSCESS 

Alveolar  abscess,  acute  or  chronic,  may  be 
followed  by  any  of  the  sequelae,  local  or  general, 
that  are  common  to  germ  foci  in  all  parts  of 


the  body,  the  anatomy  of  the  part  giving  rise, 
in  addition,  to  distinctive  local  diseases,  and 
food  contamination  to  a  special  possibility  of 
intestinal  symptoms. 

Local  Sequelae. — Glandular  enlargement  and 
glandular  abscess.  Probably  glandular  eidarge- 
ment  occurs  in  all  cases  of  alveolar  abscess,  acute 
or  chronic,  but  is  often  so  transient  or  slight  as  to 
escape  notice.  On  the  other  hand,  in  acute  cases 
the  enlargement  may  rapidly  run  on  to  suppura- 
tion, and  in  chronic  cases  an  insidious  eidarge- 
ment  slowly  spreading  from  gland  to  gland  may 
lead  to  a  diagnosis  of  lymphadenoma — a  disease 
that  may,  indeed,  be  originated  by  chronic 
dental  sepsis.  The  possibility  of  infective 
lymph  taking  an  alternative  route,  whereby 
certain  groups  of  glands  may  be  entirely  left 
out,  may  lead  to  the  appearance  of  swollen 
glands  remote  from  and  apparently  unconnected 
with  the  septic  tooth ;  this  is  seen  in  the  case 
of  the  lower  cervical  glands.  Acute  glandular 
abscess,  especially  sub-mental,  may,  in  common 
with  the  originating  abscess,  be  so  embedded  in 
a  mass  of  inflammatory  tissue  as  to  give  rise 
to  no  suspicion  of  a  second  pus  focus.  Not 
infrequently  the  glands  enlarged  by  infection 
of  acute  or  chronic  abscess  fail  to  regain  their 
normal  size,  even  after  removal  of  the  primary 
cause.  If  excised  and  exammed,  such  glands 
are  generally  found  to  be  tuberculous  ;  when  left 
to  themselves  they  may  caseate,  and  eventually 
form  a  cold  or  tubercular  abscess.  The  source 
of  tubercular  infection  in  these  cases  seems  not 
to  be  the  tooth  or  its  infected  socket — the 
tubercle  bacillus  may  gain  an  entrance  by  the 
tooth  socket,  but  the  rarity  of  tubercular  disease 
of  the  gum  or  alveolar  bone  negatives  this  view, 
and  observations  as  to  this  mode  of  entry  have 
not  been  subjected  to  the  crucial  test  of  inocula- 
tion into  guinea-pigs.  The  probabiHty  is  that 
the  germs  find  an  entry  through  the  tonsils  or 
naso -pharyngeal  mucosa  or  may  be  brought  by 
the  general  blood-stream.  Glands  that  have 
enlarged  rapidly  as  the  result  of  acute  dental 
abscess,  and  later  have  been  excised,  have 
jjresented  tuberculous  changes,  leaving  no  doubt 
that  the  tuberculosis,  though  unsuspected,  long 
antedated  the  secondary  dental  infection.  Ob- 
servations have  been  made  indicating  that  the 
circulation  of  tubercle  bacilli  in  the  blood-stream 
is  a  commoner  phenomenon  than  is  generally 
believed.  Septic  teeth  must  be  extracted  in  all 
cases  of  obstinate  cervical  glandular  enlargement. 

Scarring. — A  disfiguring  scar  adherent  to  the 
bone  is  a  common  sequel  to  the  formation  of 
an  external  sinus.  It  is  best  prevented  by  early 
evacuation  of  pus,  if  necessary  externally. 
Sometimes  it  is  possible,  by  stripping  up  the 
periosteum  in  the  direction  of  the  centre  of  the 
inflammatory  swelling,  to  reach  a  sub-periosteal 
abscess  that  threatens  to  burst  externally,  and 


677 


so  evacuate  its  contents  into  the  mouth.  The 
use  of  a  two-way  cannula  will  assist  syringing. 
When  a  scar  has  formed,  its  adhesion  to  the 
bone  may  be  divided  by  means  of  a  tenotomy 
knife,  and  the  part  massaged,  that  is,  rubbed 
and  drawn  in  various  directions  to  j^revent  con- 
traction of  cicatricial  tissue  ;  probably  massage 
will  be  needed  daily  for  some  years.  In  recent 
cases  fibrolysin  may  be  tried. 

Acute  Spreading  Osteitis  may  originate  in  the 
same  infection  as  gave  rise  to  the  original 
abscess,  and  generally  ends  in  necrosis.  The 
persistence  or  aggravation  of  pain  and  tender- 
ness, and,  still  more,  the  spread  of  these  symp- 
toms, indicates  a  serious  condition  of  osteitis, 
and  is  a  warning  of  probable  necrosis. 

Chronic  Osteitis  may  follow  an  acute  or 
chronic  alveolar  abscess,  and  may  end  in  the 
incej>tion  of  an  intractable  neuralgia,  either  tnie 
neuralgia  major,  or  a  neuralgia  due  to  com- 
pression of  nerve  filaments  by  the  chronic 
formative  osteitis — sometimes  referred  to  as 
"  toothache  without  teeth  ". 

Persistent  chronic  osteitis  is  more  generally 
due  to  periodontal  infection  than  to  infection 
tlirough  the  tooth-pulp. 

Septic  Phlebitis. — Spreading  septic  phlebitis 
may  originate  in  a  dental  abscess,  and  by 
extension  along  the  deep  facial  plexus  of  veins 
may  cause  intra-cranial  abscess  and  thrombosis 
of  the  cavernous  sinus. 

Infective  or  Spreading  Cellulitis. — Cellulitis  may 
spread  in  any  direction  from  an  alveolar 
abscess  as  the  focus,  and  may  be  started  by 
injudicious  injection  into  an  inflammatory  area. 
It  may  be  of  any  degree  of  virulence.  Spreading 
to  the  orbit  it  sometimes  gives  rise  to  orbital 
cellulitis,  or  in  less  acute  cases  to  apparently 
causeless  optic  neuritis  or  retro-bulbar  neuritis. 
In  the  mandibular  articulation  it  may  cause 
a  destructive  arthritis.  Spreading  down  the 
throat  to  the  naso-pharynx,  larynx  or  pharynx, 
according  to  the  degree  of  severity,  it  gives 
rise  to  forms  of  cellulitis  that  vary  from  an 
almost  transient  oedema  of  the  mucous  mem- 
brane to  a  rapidly  sloughing  cellulitis.  This 
severe  form  is  often  known  as  Ludwig"s  angina, 
or  acute  cervical  cellulitis.  It  starts  more 
commonly  as  an  infection  from  teeth  foul  and 
uncleaned,  coated  with  tartar,  and  affected  with 
pyorrhoea,  than  from  alveolar  abscess,  but  is 
conveniently  described  here.  Its  spread  is  gener- 
ally rapid  and  accompanied  by  oedematous 
inflammatory  exudation,  giving  rise  to  a  painful 
swelling,  but  at  first  to  little  or  no  pus  formation. 
Wlien  originating  from  the  lower  teeth,  there  may 
be  extremely  rapid  swelling  of  the  loose  tissues  , 
of  the  floor  of  the  mouth  and  tongue.  If  spread 
takes  place  backwards,  from  whatever  part  ' 
originating,  there  wiU  be  oedema  of  the  fauces. 


epiglottis,  and  base  of  the  tongue  ;  of  the  larynx 
reaching  to  the  glottis,  where  it  is  arrested  by 
the  intimate  union  of  the  mucous  membrane 
to  the  vocal  cords ;    and  of  the  walls  of  the 
pharynx,    giving   rise   to    imminent   danger   of 
death  by  suffocation  on  the  one  hand,  and  on 
the    other,    to    dysphagia    or    actual    aphagia. 
Spread  of  the  disease  externally  down  the  neck 
!  may  also  lead  to  suffocation  by  j)ressure  of  the 
tense    inflammatory    exudation    beneath    tense 
cervical  fascia.     Symptoms  of  general  intoxica- 
tion rapidly  supervene.     At  the  commencement 
there  may  be  shivering  or  an  actual  rigor ;   the 
temperature   may   rise   to    105°   F.,   but   more 
generally    to    about    101° ;     the    patient    may 
complain    of    headache    and    general    malaise. 
Wlien  infection  is  very  virulent,  the  disease  may 
be  rapidly  fatal  either  by  suffocation  or  by  acute 
intoxication.     In   less  acute  cases  widespread 
pus  formation  and  gangrene  of  soft  parts  may 
follow.     In  the  more  favourable  forms,  where 
resistance  is  good,  complete  resolution  occurs 
in  a  few  days.     The  dangerous  cases  are  those 
in  which  there  is  lividity  and  dysphagia,  pointing 
to  such  swelling  of  the  larynx  and  pharynx  as 
to  obstruct  respiration,  and  those  in  which  the 
general    temperature    is   low    (100°    or    lower, 
asthenic),  as  compared  with  the  extent  of  the 
local   lesion.     On   cutting   into   the   tissues   in 
search  of  pus  or  to  relieve  inflammatory  tension, 
they  will  be  found  unresilient  and  matted  to- 
gether, and  there  will  be  a  free  escape  of  serous 
fluid ;     but   at   first   pus   formation   is   absent, 
except  at  the  focus  of  the  disease  when  its  origin 
is    an    alveolar    abscess.     Every    intermediate 
form   of    clinical    reaction   may   be   met    with 
between    the    wide-spread    and    varulent    type 
described  above  and  a  transient  erythema,  the 
area  affected  varying,  but  all  owning  the  one 
cause  (septic  teeth),  and  all  being  dependent  on 
infection  by  similar  germs ;   dose  and  virulence 
are  balanced  against  resistance.     The  treatment 
of  these  conditions  usually  requires  the  aid  of 
a  surgeon. 

Infection  of  the  Maxillary  Sinus  is  a  not 
infrequent  sequel  of  alveolar  abscess,  and  is  to 
be  suspected  when  an  acute  "face-ache" 
suddenly  clears  up  without  external  discharge 
(see  Chapter  XLIII). 

Blood  infections,  acute,  subacute,  and  chronic 
(septicaemia,  sapraemia),  depending  on  the 
greater  or  less  amount  and  relative  quantities 
of  germs  and  toxins  absorbed,  pyaemia  with 
distant  abscesses  and  mfarcts,  may  result  from 
a  dental  abscess.  These  processes  are  more  fre- 
quently the  result  of  general  dental  sepsis  than 
of  a  single  dental  abscess  (see  Chapter  XLVI). 

For  an  account  of  intestinal  symptoms  due 
to  food  contamination  see  same  Chapter. 

J.G.T. 


CHAPTER    XLIII 

EMPYEMA   OF   THE   MAXILLARY   SINUS 


Empyema,  or  "  abscess  of  the  maxUlary 
sinus  ",  are  terms  used  to  signify  the  presence 
of  pus  within  the  sinus  and  produced  by  acute 
or  chrome  inflammation  of  its  lining  mucous 
membrane. 

Aetiology. — It  is  ahnost  universally  agreed  that 
acute  inflammation  of  the  maxillary  sinus  is  most 
frequently  due  to  intra- nasal  infection  arising 
during  the  course  of  one  of  the  acute  specific 
fevers,  and  of  these  influenza  has  proved  itself 
by  far  the  most  prolific  factor,  while  pneumonia, 
diphtheria,  measles,  scarlet  and  enteric  fevers, 
account  for  a  smaller  number  of  cases.  Further- 
more, there  can  be  little  doubt  that  empyema 
may  be  produced  by  the  infective  organisms 
that  give  rise  to  acute  coryza  or  "cold  in  the 
head ".  Less  commonly  the  inflammation 
is  induced  by  infective  elements  derived  from 
a  diseased  tooth  in  the  immediate  neighbour- 
hood of  the  sinus. 

Stroebel's  (Dresden)  statistics  show  that  intra- 
nasal infection  ^\ill  account  for  64-6  per  cent 
of  inflammations  of  the  maxillary  sinus,  while 
only  29  per  cent  are  due  to  dental  causes.  The 
remainder  arise  from  rarer  factors,  such  as 
traumatism,  syphilis,  tubercle,  mahgnant  dis- 
ease, etc. 

It  will  thus  be  noticed  how  completely  this 
view  is  opposed  to  the  old  notion  that  abscess 
of  the  maxillary  smus  was  invariably  caused 
by  a  diseased  tooth.  The  error  probably  arose 
from  the  facts  that  dental  surgeons  rarely  saw 
any  cases  but  those  that  were  really  due  to 
diseased  teeth,  and  were  therefore  impressed 
with  this  mode  of  origin,  while  general  surgeons, 
as  \vell  as  their  confreres  who  devoted  special 
study  to  the  diseases  of  the  nose,  were  quite 
satisfied  to  regard  an  empyema  as  of  dental 
origin  if  a  premolar  or  molar  tooth  possessed 
a  small  focus  of  caries  or  any  other  sign  of 
disease.  To-day  it  is  known  "that,  with  very 
rare  exceptions,  e.  g.  pyorrhoea  alveolaris, 
only  a  dead  tooth  with  a  septic  i3ulp-cavity 
can  cause  suppuration  of  the  corresponding 
maxillary  sinus. 

In  certain  cases  it  will  be  doubtful  which 
aetiological  factor  has  played  the  more  promi- 

»  The  writer  wishes  to  state  that  lie  has  endeavoured 
to  treat  this  subject  from  tlie  point  of  view  of  the 
dental  surgeon,  and  only  to  emphasize  those  aspects  of 
It  that  should  be  of  interest  to  members  of  that  branch 
of  the  profession. 


678 


nent  part,  and  under  such  circumstances  the 
best  interests  of  the  patient  and  of  his  medical 
and  dental  advisers  wiM  be  served  if  the  latter 
bring  together  those  special  experiences  which 
have  been  gained  by  each  working  from  opposite 
sides  of  a  somewhat  neutral  territory. 

Leaving  aside  empyemata  of  intra-nasal 
origin,  those  that  are  caused  by  diseases  of  the 
teeth  may  now  be  reviewed  in  more  detail. 

EMPYEMA    DUE   TO    DENTAL  CAUSES 

Wlien  it  is  remembered  that  there  is  a  close 
comiection  between  the  vascular  system  of  the 
deeper  muco-periosteal  layers  of  the  lining 
membrane  and  the  coarse-meshed  vascular 
system  of  the  spongy  bone  of  the  alveolus, 
and  also  of  the  latter  with  the  fine  network 
of  vessels  of  the  alveoli  and  the  roots  of  the 
teeth,  it  is  not  surprising  that  inflammation 
may  readUy  travel  from  a  dental  focus  to  the 
maxillary  sinus  without  any  direct  continu- 
ity of  surface.  Still  more  easily  will  such  in- 
fection be  transmitted  if  a  diseased  root-apex 
projects  into  the  sinus  and  is  only  separated 
from  its  cavity  by  a  very  thin  layer  of  bone 
or  even  of  mucous  membrane. 

This  intimate  anatomical  relationship  has 
led  many  distinguished  rhinologists  to  the  beUef 
that  the  maxillary  sinus  may  be  infected  from 
carious  foci  in  a  living  tooth,  the  materies  morbi 
being  conveyed  along  the  blood  or  lymph  vessels, 
or  nerves.  But,  as  has  already  been  stated, 
there  are  very  few  exceptions  to  the  rule  that 
only  a  dead  tooth  with  a  septic  puljj-cavity  can 
cause  suppuration  in  the  superjacent  sinus. 

Empyemata  of  dental  origin  may  be  divided 
into  two  main  forms  ^ — 

( 1 )  Those  due  to  acute  inflammatory  changes 

around  the  diseased  root  of  a  tooth. 

(2)  Those   caused   by   chronic   inflammatory 

changes. 

1.  Acute  Inflammatory  Changes 

(a)  Acute  root  abscess. 
(h)  Acute  periostitis. 

(c)  Circumscribed  or  diffuse   osteitis   of  the 
alveolar  process. 

'  The  writer  wishes  to  acknowledge  the  use  he  has 
made  in  this  classification  of  Hajek's  treatise.  Patho- 
logic und  Tlierapie  der  entzundlichen  Erkrankungen  der 
Nebenhohlen  der  Nase,  1909. 


679 


(a)  Acute  Root  Abscess. — This  condition 
develops  as  a  result  of  periodontitis  secondary 
to  inflammation  of  the  pulp  of  a  carious  tooth. 
The  roots  of  the  second  premolar  and  the  molars 
are  in  close  contact  with  the  floor  of  the  maxil- 
lary sinus,  and  emjiyema  of  that  cavity  is  a  not 
infrequent  result  of  septic  periodontitis  con- 
nected with  them.  The  well-known  symptoms 
of  severe  toothache,  pain  on  pressure,  sensation 
of  elongation  of  the  tooth,  possibly  a  painful 
swelling  over  the  alveolus,  and  the  relief  of 
these  symptoms  simultaneously  with  a  dis- 
charge of  foul  pus  from  the  nose  or  into  the 
nasopharynx,  are  too  well  known  to  need 
description  here. 

If  the  tooth  is  extracted  a  probe  may  find 
easy  access  to  the  sinus,  but,  on  the  other 
hand,  the  communication  between  the  alveolus 
and  the  sinus  may  barely  admit  a  fine  probe, 
and  then  only  after  patient  and  careful  mani- 
pulation. In  some  instances  no  direct  communi- 
cation can  be  found,  and  the  question  will  arise  : 
Has  the  infection  entered  by  way  of  bone, 
blood  or  lymph  vessels,  or  nerve-sheath  ? 

(b)  Acute  Periostitis  may  aSect  the  alveolus 
as  a  result  of  dental  disease,  and  the  resulting 
abscess  may  break  into  the  maxillary  smus  as 
well  as  externally  on  the  gum.  Wlien  periostitis 
appears  after  extraction,  the  sinus  seems 
especially  liable  to  inflammation,  possibly  on 
account  of  infection  having  taken  place  during 
the  operation  or  shortly  afterwards. 

(c)  Circumscribed  or  Diffuse  Osteitis  of  the 
Alveolar  Process  resulting  from  dental  disease, 
trauma,  or  septic  osteomyelitis  of  the  upper 
jaw,  may  induce  suppuration  of  the  sinus. 

2.  Chronic  Inflammatory  Changes 

(a)  Chronic  inflammation  of  the  periodontal 

membrane. 
(6)  Infection  of  the  maxillary  sinus  by  way 

of  the  root-canal  of  a  dead  tooth. 

(c)  Empyemata  caused  by  dental  treatment. 

(d)  Pyorrhoea  alveolaris. 

(a)  In  periodontitis  there  frequently  develops 
a  small  suppurating  cyst  on  the  root-apex,  or 
possibly  only  a  small  mass  of  granulations.  In 
either  case  these  may  by  their  growth  reach 
and  infect  the  mucous  membrane  of  the  sinus, 
owing  to  slow  and  often  painless  absorption 
of  the  intervening  bone. 

(6)  The  Traversing  of  the  Alveolar  Process  by 
Infection  derived  from  an  Inflamed  Dental  Root. 
WTien  a  pulp  becomes  septic — even  under  a 
harmless  looking  filling — communication  may 
be  established  with  the  siiuis  by  way  of  the 
root-canal,  and  a  fine  passage  through  a  con- 
siderable thickness  of  alveolus.  Here  agam  the 
diseased  tooth  may  not  be  unduly  sensitive  to 
pressure,  tapping,  or  thermal  changes. 


(c)  Empyema  following  Dental  Treatment. 
Instances  of  this  have  arisen  when  a  bristle 
or  di'ill  has  been  pushed  up  too  far  through 
an  unclean  pulp-cavity,  and  an  apical  granuloma 
has  been  infected  or  a  root  abscess  caused, 
either  of  which  may  eventually  infect  the 
sinus. 

(d)  Pyorrhoea  Alveolaris. — That  this  condition 
may  lead  to  empyema  is  now  an  estabUshed 
fact. 

EMPYEMA    OF    TRAUMATIC    ORIGIN 

In  this  category  must  be  included  empyemata 
following  upon  nasal  and  dental  operations. 
The  application  of  the  galvano-cautery  to  the 
middle  meatal  region,  and  other  operations  in 
this  vicinity,  have  occasionally  j)roduced  inflam- 
mation of  the  sinus,  and  the  same  may  be  said  of 
skilful  as  well  as  unskilful  extraction  of  difficult 
upper  molar  roots.  In  the  latter  the  sinus 
may  have  been  opened  and  infected  at  the 
time  of  operation ;  or,  at  a  subsequent  period 
septic  material  may  have  gained  access  from 
the  mouth. 

Similarly,  projectiles  and  other  sharp  bodies 
may  find  their  way  into  and  cause  infection  of 
the  sums.  In  these  instances,  as  weU  as  those 
of  dental  origin,  there  is  some  laceration  of  the 
lining  mucous  membrane,  with  consequent 
bleeding  and  infection  of  the  blood-clot. 

In  malignant  disease  of  the  maxillary  sinus 
the  pus  is  often  very  foetid  and  blood-stained, 
while  the  intense  pain,  and  later  on  the  distension 
of  the  walls,  soon  indicate  the  serious  nature  of 
the  malady. 

In  syphilitic  and  tuberculous  disease  of  the 
upper  jaw,  there  are  generaUy  present  other 
unmistakable  signs  of  the  general  disease,  while 
locally  sequestra  of  necrosed  bone,  forming 
some  part  of  the  alveolus  or  the  walls  of  the 
sinus,  may  frequently  be  recognized. 

Pathology. — In  acute  inflammation  there  is 
marked  hyperaemia  and  oedema  with  scattered 
points  of  interstitial  haemorrhage.  Microscopic 
examination  shows  ceU  infiltration  and  oedema 
in  the  superficial  layer  and  around  the  glands. 
The  \viiter  believes  that  the  infiltration  of  the 
mucous  membrane  may  be  so  great  as  practicaUy 
to  obliterate  the  lumen  of  the  maxillary  sinus, 
because  occasionally  on  puncturing  such  cases 
there  has  been  great  resistance  to  the  injection 
of  the  fluid  used  for  irrigation,  and  this  in  spite 
of  any  change  of  position  of  that  portion  of  the 
camrala  witliin  the  sinus. 

In  chronic  inflammation  a  purulent  deposit 
will  be  found  on  the  mucous  membrane.  The 
latter  is  often  greatly  thickened,  and  may 
contain  scattered  spaces  indicating  lymph  or 
cystic  cavities.  The  ciUated  epithelium  may 
be   absent  in  parts,  or  in  others  approximate 


680 


to  the  squamous  type,  while  active  leucocytic 
exudation  takes  place  between  the  cells.  A 
certain  amount  of  engorgement  of  the  vessels 
will  be  present,  and  around  their  walls  small- 
celled  infiltration  is  generally  well  marked. 

\Mien  the  chronic  inflammatory  changes 
spread  to  the  muco-periosteal  layers,  there  may 
be  some  thickening  of  the  underlying  bone,  or 
this  may  appear  to  be  eroded  with  numerous 
lacuna-like  depressions.  Readers  interested  in 
this  matter  should  consult  references  2,  3,  7,  14. 

Other  pathological  sequelae  of  chronic  sup- 
puration are — 

(a)  Cysts   in    the    siiius,    due    to    cicatricial 

stenosis   of   the   mouths   of   lymjihatic 

gland  ducts. 
(6)  Nasal  polypi,  which  are  usually  met  with 

in   the  neighbourhood  of  the   opening 

(ostium). 
(c)  Osteophytes,    which    are    found    in    the 

deeper  or  muco-periosteal  layers. 
((/)  Serious  complications — a  rare  occurrence  ; 

these  are  generally  due  to  an  infective 

spreading  periostitis. 

Dental  Cysts.  —  These  formations  are  not 
primarily  due  to  suppuration  within  the  sinus, 
but  they  may  cause  it,  and  have  to  be  differ- 
entiated from  chronic  empyema.  They  are 
most  probably  developments  from  the  epithelial 
remains  of  the  enamel-germ ;  and  arising  in 
connection  with  the  roots  of  a  tooth,  they  may 
by  their  growth  extend  into  and  encroach  on  the 
sinus  so  as  entirely  to  fill  its  lumen.  These 
cysts  contain  a  clear  fluid  and  cholesterin 
crystals,  but  repeated  attacks  of  inflammation 
may  alter  the  colour  and  consistency  of  the 
fluid,  or  even  induce  suppuration. 

Bacteriology. — In  acute  empyema  of  influenzal 
origin  pure  cultures  of  the  influenza  bacillus 
have  been  found  (11).  As  a  general  rule  a 
mixed  infection  is  present,  in  which  the  diplo- 
coccus  pneumoniae  is  prominent,  together  with 
the  staphylococcus  pyogenes  aureus  and  albus, 
streptococcus  pyogenes,  and  baciUus  coH. 

Lewis  and  Turner  (10),  amongst  other  con- 
clusions, have  shown  "  that  the  pus  obtained 
from  some  cases  of  suppuration  witliin  the  sinus 
may  contain  organisms  similar  to  those  occurring 
in  the  buccal  cavity ;  that  occasionally  bacilli 
distinctive  of  dental  caries  may  be  isolated 
from  the  pus ;  that  in  the  cases  of  chronic 
suppuration  streptococci  were  found  in  80 
per  cent,  while  in  the  more  recent  cases  they 
occurred  in  60  per  cent ;  that  in  recent  cases 
virulent  organisms  are  met  with  twice  as  often 
as  in  cases  of  chronic  suppuration  ;  that  clinical 
evidence  supports  the  view  that  the  sinus  is 
more  frequently  infected  by  way  of  the  nasal 
cavity;  and  that  this  opinion  is  corroborated 
by  bacteriological  investigation." 


Since  the  symptoms,  diagnosis,  prognosis  and 
treatment  vary  so  -widely  according  as  the 
inflammation  of  the  sinus  is  acute  or  chronic, 
it  may  conduce  to  clearness  if  the  two  conditions 
are  discussed  separately. 

ACUTE    INFLAMMATION 
Symptoms. — These  are  both  local  and  general. 

(1)  Subjective  Local  Symptoms — 

(a)  Pain  is  nearly  always  present  when  the 

inflammation  is  due  to  acute  influenzal 
or  to  dental  infection.  In  the  latter  case 
acute  toothache,  associated  with  tender- 
ness and  swelling  over  the  alveolus, 
may  precede  the  suppuration  of  the 
maxillary  sinus,  and  be  quickly  relieved 
by  a  discharge  of  pus  from  the  corre- 
sponding nostril  or  into  the  naso- 
pharynx. 

The  pain  of  acute  inflammation  of  the 
sinus  is  often  very  severe  and  is  felt 
deeply  in  the  cheek.  As  a  rule  it  is  of 
a  tense  throbbing  nature,  and  is  much 
increased  if  the  patient  bends  the  head 
downwards  and  forwards.  It  is  also 
accentuated  by  pressure  applied  over 
the  canine  fossa,  the  malar  bone,  and 
especially  over  the  ascending  process 
of  the  superior  maxiUary  bone.  The 
pain  may  radiate  to  the  supra-orbital 
region  even  though  the  frontal  sinus 
and  ethmoidal  cells  are  free  from 
inflammation. 

The  offending  tooth  wfll  generally  be 
painful  if  pressed  upon  or  tapped,  and 
will  often  feel  as  if  it  were  too  long  when 
a  firm  bite  is  made  upon  it. 

(b)  Discharge  of  Pus.- — A   discharge   of  foul 

pus  from  the  corresponding  nostril  or 
into  the  naso-pharynx  is  generally 
associated  with  rehef  of  the  pain. 
Tliis  symptom  is  nearly  always  noted 
by  the  patient. 

(c)  Foul  Smell  or  Impairment  of  Smell. — If 

the  discharge  escapes  into  the  naso- 
pharynx or  is  small  in  amount,  the 
patient  may  not  notice  it  and  will  only 
complain  of  a  putrid  smell — in  fact,  this 
may  be  the  one  nasal  symptom  that 
he  is  aware  of.  On  the  other  hand 
loss  or  impairment  of  smell  may  be  due 
to  obstruction  of,  or  acute  inflamma- 
tory changes  in,  the  olfactory  region 
of  the  nose. 

(2)  Objective  Local  Symptoms — 

(a)  The  dental  conditions  that  have  already 
been  referred  to  as  aetiological  factors. 


681 


(b)  Examination  of  the  nose  will  usually 
reveal  pus  in  the  middle  meatus,  or  on 
the  posterior  phar\^lgeal  wall  in  those 
cases  where  the  discharge  is  prevented 
from  flowing  for\\ards  by  various  forms 
of  intra-nasal  obstruction  {vide  Chronic 
Inflammation). 

(3)  General  Symptoms. — There  may  be  acute 
pyrexia  rising  to  102°-104°,  with  its  attendant 
symptoms  of  general  malaise,  anorexia,  etc. 
^Vhen  the  inflammation  is  caused  by  one  of 
the  acute  specific  fevers,  the  local  symptoms 
are  often  largely  overshadowed  by  those  due 
to  the  general  constitutional  infection.  This 
is  well  marked  in  influenza,  enteric  fever,  and 
pneumonia,  although  in  the  first  named  the 
"  neuralgia  ",  as  it  is  frequently  termed,  may  be 
intense  in  its  severity. 

Diagnosis. — In  dental  cases  this  will  largely 
depend  on  the  history  of  an  antecedent  tooth- 
ache, which  was  relieved 
by  the  appearance  of  a 
purulent  discharge  from 
the  nose.  Examination 
of  the  nasal  cavity  may 
reveal  a  collection  of  pus 
in  the  middle  meatus, 
l)ut  if  this  sign  be  want- 
ing, it  may  yet  be 
possible  to  establish  it 
by  asking  the  patient  to 
turn  the  affected  cheek 
upwards  for  a  minute, 
so  that  the  pus  may  be 
encouraged  to  flow  into 
the  nose. 

The  transillumination 
test  (vide  Chronic  Em- 
pyema) is  not  of  great 
value  in  acute  inflam- 
mation, although  a 
slight  diminution  in 
translucency  may  be 
noticed  on  the  affected 
side. 

If  there  is  still  doubt 
as  to  the  diagnosis,  the 
maxillary  sinus  should  be  explored  by  trocar 
and  cannula  {vide  Chronic  Suppuration). 

Prognosis.^Acute  empyema  of  dental  origin 
nearly  always  recovers  quickly  if  the  diseased 
tooth  is  removed,  and  the  sinus  is  freely 
drained  and  cleansed  once  or  twice  daily  with 
a  mild,  non-irritating  antiseptic. 

Wlien  the  infection  occurs  in  the  course  of  an 
acute  specific  fever,  the  prognosis  must  be 
guarded,  because  a  more  intimate  inflammation 
of  the  mucous  membrane  takes  place  and  the 
general  resistance  of  the  patient  is  lowered. 
Treatment. — It    will     be    obvious    that    the  i 


Fig.  908. 
{Mayer  &  Meltzer.] 


diseased  tooth  .should  be  at  once  removed,  and 
communication  made  ^^ith  the  maxillary  sinus 
by  way  of  the  alveolus  (see  Fig.  908).  It  can- 
not be  impressed  too  firmly  on  the  dental 
surgeon  that  a  free  communication  should  be 
made,  i.  e.  at  least  equal  to  the  calibre  of  an 
ordinary  slate-pencil.  If  a  small  puncture  is 
made  it  will  rapidly  contract,  and  the  pain 
in  passing  the  nozzle  of  a  syringe  through  the 
alveolus  will  be  so  great  that  the  patient  will 
discontinue  the  necessary  after-treatment  before 
the  mucous  membrane  of  the  sinus  has  returned 
to  its  normal  condition. 


Fig.  909.— H.  Tilleys  Vulcanite  Plug. 

(Mayer  <fc  Meltzer.) 

To  maintain  the  patency  of  the  passage 
the  writer  recommends  a  solid  vulcanite  plug 
with  a  milled  shank  and  flat-flanged  head 
(see  Fig.  909). 

During  the  first  three  days  this  should  be 
removed  thrice  daily,  and  the  sinus  irrigated 
with  half  a  pint  of  warm  normal  saline  solution, 
weak  Condy's  fluid,  or  saturated  boracic  acid 
lotion.  As  the  pus  diminishes,  irrigation  should 
be  practised  twice  daily,  and  later  once  daily, 


Fig.  910. 


(Mayer  d:  Meltzer.) 


then  on  alternate  days;  and  finally,  if  after  an 
interval  of  four  to  five  days  no  pus  returns 
when  the  sinus  is  cleansed,  the  tube  should 
be  left  out  overnight,  and  the  sinus  irrigated 
once  daily  as  long  as  the  communication  will 
permit  the  passage  of  the  fine  nozzle  of  the 
syringe.  The  whole  treatment  will  often  result 
in  cure  within  the  space  of  a  fortnight. 

The  best  syringe  for  the  purpose  is  a  Hig- 
ginson's  enema  syringe,  fitted  with  a  straight 
uncurved  nozzle  (see  Fig.  910). 


682 


The  writer  recommends  a  solid  plug  in  pre- 
ference to  a  tube,  because  the  latter  soon  be- 
comes clogged  with  food,  mucus  or  other 
septic  material,  and  therefore  tends  to  con- 
taminate the  sinus. 

Wlien  the  acute  suppuration  is  due  to  intra- 
nasal infection,  the  sinus  should  be  irrigated 
daily  by  intra-nasal  puncture  through  the 
inferior  meatus,  or  by  way  of  the  natural 
opening,  until  the  discharge  lessens  or  ceases 
altogether.  Under  these  circumstances  removal 
of  a  sound  tooth,  or  even  a  diseased  tooth 
that  can  be  preserved,  is  unwarrantable. 

CHRONIC    EMPYEMA 
Symptoms. — (1)  Subjective  Local  Symptoms — 

(a)  Pain.     This    is    rarely    a    very    niarked 

symptom,  but  when  present  it  is  fre- 
quently due  to  an  acute  exacerbation 
of  the  "chronic  inflammation.  When  it 
is  more  persistent  than  severe,  it  will 
frequently  be  found  that  there  is  some 
obstruction  to  the  flow  of  pus  through 
the  natural  ostium. 

Not  uncommonly  the  pain  is  referred 
to  the  supra-orbital  region,  and  may  be 
most  marked  during  the  forenoon — a 
periodicity  which  has  often  suggested 
the  malarial  origin  of  the  headache. 
There  is  rarely  any  neuralgia  of  the 
supra-dental  nerves.  Excesses  in  eat- 
ing, drinking,  and  smoking  will  fre- 
quently increase  the  pain. 

(b)  Purulent  Nasal  Discharge.— This  is  often 

the  only  symptom  of  which  the  patient 
complains.  The  discharge  is  commonly 
blown  into  the  handkerchief,  but  various 
forms  of  nasal  obstruction  may  con- 
strain it  to  pass  entirely  into  the  naso- 
pharynx, and  hence  the  patient  may 
only  comjjlain  of  "  post-nasal  catarrh  ". 
The  discharge  may  be  almost  pure  pus, 
or  mixed  with  varying  quantities  of 
mucus.  Like  the  headache,  the  dis- 
charge may  only  occur  during  the 
earUer  hours  of  the  day. 

Slight  eczema  around  the  nostril, 
attacks  of  nose-bleeding,  irritation  of 
the  pharynx,  cough  and  catarrhal 
conditions  of  the  larynx  and  lower  air- 
passages,  are  symptoms  not  infre- 
quently met  with,  and  caused  by  the 
chronic  discharge  of  pus  from  the 
maxillary  smus. 

(c)  Nasal  Obstruction. — This  is  caused  by  the 

swelling  and  congestion  of  the  nasal 
raucous  membranes,  and  often  by  the 
growth  of  pol3rpi  or  other  local  hyper- 
trophies of  the  mucosa. 


{(l)  Foul  Smell  (Cacosmia). — This  again  may 
be  the  patient's  only  grievance,  and 
he  is  particularly  liable  to  notice  it 
when  the  head  is  bent  forwards  and 
downwards. 

(2)  Objective  Symptoms. — As  in  the  acute 
cases,  examination  of  the  corresponding  nasal 
cavity  will  generally  reveal  pus  in  the  middle 
meatus,  i.  e.  between  the  lower  border  of  the 
middle  and  the  upper  border  of  the  inferior 
turbinals.  In  some  cases  the  discharge  is  not 
seen  anteriorly  owing  to  swelling  of  the  middle 
turbinal  or  a  septal  obstruction,  and  then  it 
may  only  be  visible  by  posterior  rhinoscopy.  If 
no  pus  is  present  in  the  middle  meatus  when 
the  case  is  examined,  it  may  sometimes  be  in- 
duced to  appear  if  the  patient's  head  is  turned 
so  that  the  suspected  cheek  is  uppermost — the 
foul  smell  may  also  be  noticed  at  the  same  time. 

Closer  examination  of  the  middle  meatus  may 
reveal  to  the  expert  rhinologist  certain  hyper- 
trophies or  abnormal  swellings,  polypi,  etc., 
which  need  not  be  discussed  now. 

The  writer  has  never  seen  "  swelling  or  con- 
gestion of  the  cheek  "  in  an  uncomplicated  case 
of  chronic  suppuration  of  the  maxillary  sinus. 

(3)  General  Symptoms. — The  constant  swallow- 
ing of  foul  matter  frequently  leads  to  gastric 
disturbances,  want  of  appetite,  and  general 
debility.     Such    patients    often    look    ill    and 

I  exhibit  a  cachexia    very  suggestive  of   serious 

j  constitutional  disease.  William  Hunter  has 
shown  that  some  of  the  graver  forms  of 
anaemia  are  due  to  toxins  absorbed  from  sup- 
puration in  the  nasal  sinuses,  as  well  as  from 

•  diseased  teeth. 

The  central  nervous  system  does  not  escape 
the  evil  influences  of  the  chronic  absorption  of 
toxic  products,  for  it  is  well  kno\vn  that  nervous 
depression,  lack  of  mental  concentration,  general 
apathy,  and  a  number  of  indefinite  nerve  dis- 
turbances, are  frequently  caused  by  chronic 
suppuration  of  the  maxillary  sinus,  and  quickly 
cured  by  the  removal  of  the  septic  focus. 

On  the  other  hand,  it  must  not  be  forgotten 
that  many  patients  who  are  the  subjects  of 
chronic  empyema  appear  to  enjoy  perfect 
health  and  are  almost  oblivious  of  their  nasal 
trouble.  Possibly  they  are  to  a  certain  extent 
immune,  and  yet  one  sometimes  wonders,  when 
a  strong  man  quickly  succumbs  to  septic 
pneumonia  or  some  other  acute  specific  malady, 
whether  his  sudden  collapse  was  not  due  to  the 
fact  that  he  was  severely  handicapped  in  his 
fight  by  the  presence  of  a  hidden  suppurating 
focus,  which  he  had  for  a  long  time  only  looked 
on  as  "  a  bit  of  a  nuisance  ". 

Diagnosis. — The  existence  of  any  of  the  fore- 
going   symptoms    having    been    ascertained,    a 

I  careful  examination  of  the  teeth  should  be  made, 


683 


with  special  reference  to  the  presence  of  a  dead 
tooth,  or  the  possibility  of  septic  matter  being 
retained  under  an  innocent-looking  crown  or 
filling. 

Transillumination  of  the  maxillary  sinuses 
should  next  be  undertaken,  and  every  dental 
surgeon  should  be  famUiar  with  this  simple  and 
useful  aid  in  diagnosis.  If,  in  a  darkened 
room,  a  10-volt  electric  lamp  is  placed  in  the 
patient's  mouth,  with  his  lips  tightly  closed, 
it  will  be  seen  that  in  a  normal  sinus  there  is 
a  well-marked  infra-orbital  crescent  of  Ught, 
whereas  when  the  sinus  has  been  subject  to 
chronic  inflammation,  the  light-crescent  is 
absent  on  the  diseased  side.  The  test  is  by 
no  means  pathognomonic  of  empyema,  be- 
cause any  condition  that  destroys  the  normal 


out  by  means  of  a  suitably  curved  cammla 
passed  through  the  natural  opening,  or 
"  ostium  ",  in  the  middle  meatus. 

Radiography. — If  a  good  X-ray  negative  of 
the  face  is  made,  a  sinus  containing  pus  will 
exhibit  a  blurred  indefinite  outhne  when  com- 
pared with  the  normal  sinus  on  the  healthy 
side. 

Prognosis. — An  empyema  of  dental  origin  is 
more  favourable  than  one  caused  by  the  specific 
organisms  of  one  of  the  acute  infective  diseases, 
which  gain  access  by  way  of  the  nose. 

In  both  forms  the  prognosis  is  better  when 
no  intra-nasal  obstruction  (polypi,  septal  irre- 
gularities, etc.)  hinders  free  discharge  of  the 
contents.  Excesses  in  alcohol  and  tobacco  are 
detrimental  to  the  rapid  cure  of  an  empyema, 


transmission  of  Ught  rays  will  cause  some 
degree  of  opacity,  e.  g.  repeated  attacks  of 
catarrh,  cysts  with  opaque  contents,  polypi, 
new  growths  within  the  maxillary  sinus,  etc. 
The  transillumination  test  is  only  of  value  when 
it  is  taken  in  conjunction  with  other  symptoms. 

Exploration. — Should  the  preceding  tests 
fail,  certain  information  may  be  gained  as  to  the 
presence  or  absence  of  an  empyema  by  means 
of  exploration. 

The  inner  or  median  wall  of  the  inferior  mea- 
tus is  anaesthetized  with  a  10  %  solution  of 
cocaine  and  then  pierced  with  a  suitable  trocar 
and  cannula  (see  Fig.  911).  The  trocar  is  with- 
dra-i^ai  and  the  sinus  irrigated  through  the 
cannula  with  warm  boracic  or  normal  saline 
solution.  Any  pus  contained  in  the  sinus  wUl 
at  once  be  evident  in  the  returning  fluid. 

In  other  instances  the  shins  may  be  washed 


Diseases  of  Throat  and  Nose. 
{H.  K.  Lewis.) 


and  the  same  may  be  said  of  any  general  con- 
stitutional weakness. 

Treatment. — Li  deahng  with  a  chronic  em- 
pyema both  dental  and  nasal  surgeons  should 
bear  in  mind  what  is  probably  the  condition 
of  the  hning  mucous  membrane  {vide  supra), 
and  that  above  all  things  the  great  essen- 
tial for  successful  treatment  must  be  free,  un- 
hindered, spontaneous  drainage.  Unless  the 
proposed  method  of  treatment  subserves  these 
three  essentials  it  camiot  be  considered  as 
scientifically  conceived  or  surgically  sound. 
These  remarks  apply  to  all  cases,  whether  they 
be  of  nasal  or  dental  origin. 

When  the  history  and  symptoms  point  to  the 
dental  origin  of  the  empyema,  it  is  obvious  that 
the  diseased  tooth  or  teeth  must  be  removed, 
or  any  other  source  of  infection,  e.  g.  pyorrhoea, 
carefuUy  treated.     This  having  been  done,  the 


684 


question   arises :   How  is  the  empyema  to    be 
cured  ? 

Formerly  it  was  the  universal  custom  (and 
it  is,  indeed,  far  too  prevalent  to-day)  to  adopt 
alveolar  drainage,  and  only  to  fall  back  on  otlier 
methods  when  this  failed,  or  the  patient  became 
weary  of  the  treatment. 


Fig.   912. — H.   Tilley  :  Diseases  of   Throat  and  Nose. 

(H.  K.  Lewis.) 


That  alveolar  drainage  must  necessarily  fail 
in  a  great  proportion  of  clironic  cases,  even 
those  of  dental  origin,  should  be  obvious,  if  it  is 
remembered  to  what  a  state  of  degeneration 
the  mucous  membraneof  the  sinus  has  frequently 
attained.  It  is  incredilile  that  merely  irrigating 
this  once  or  twice  daily  with  a  niUd 
antiseptic  lotion  can  hasten  its  return 
to  a  normal  condition.  The  tubes  that 
are  inserted  on  the  supposition  that 
they  drain,  rarely  effect  this  purpose,  for 
they  soon  become  clogged  with  coagu- 
lated mucus  or  food  particles,  and  even 
if  they  do  not  do  so  they  afford  a  free 
channel  througli  A\liich  the  sinus  may  be 
contaminated  from  tlie  moutli.  Not 
infrequently  the  upper  end  of  such  tube 
projects  a  quarter  to  half  an  inch  above 
the  floor  of  the  sinus,  and  hence,  until 
the  pus  reaches  the  level  of  the  tube, 
the  floor  is  bathed  with  septic  accumu- 
lations. If  a  solid  plug  is  inserted,  then 
drainage  cannot  take  place  at  all  except 
for  a  few  moments  when  irrigation  is 
being  practised. 

No  doubt  both  dental  and  nasal 
surgeons  can  recall  cases  of  chronic 
empyema  that  they  have  cured  by  alveolar 
drainage,  but  they  will  remember  an  infinitely 
greater  number  that  have  only  been  improved, 
and  in  these  the  patient  has  been  obliged  to 
persist  in  a  wearisome  treatment  by  irrigation 
because  failure  to  do  so  has  meant  a  return  of 


the  old  symptoms.  In  other  words,  such  cases 
are  failures  when  the  question  of  cure  is  being 
discussed. 

Is  there  any  method  of  treating  a  chronic 
empyema  of  nasal  or  dental  origin  that  offers 
to  the  patient  a  fair  and  reasonable  chance 
of  rapid  cure  ?  This  question  can  be  readily 
and  honestly  answered  in  the 
affirmative  if,  in  addition  to 
appropriate  dental  treatment,  the 
patient  will  consent  to  an  opera- 
tion lasting  for  a  few  minutes 
longer  than  the  short  time  required 
for  alveolar  puncture. 

The  procedure  involves  the 
establishment  of  a  large  perma- 
nent opening  in  the  inner  wall, 
the  lower  circumference  of  the 
opening  being  level  with  the  floor 
of  the  diseased  sinus. 

Oj)eration.  —  Under  general 
anaesthesia  the  anterior  two- 
thirds  of  the  inferior  turbinal  is 
removed  by  means  of  scissors  and 
cold  wire  snare,  so  that  the  inner 
or  nasal  wall  of  the  sinus  is  ex- 
posed (.see  Figs.  912,  913).  By 
means  of  suitable  forceps,  burrs 
or  curved  knives,  an  opening  at  least  the  size  of 
a  sixpence  is  made  in  the  inner  wall,  and  especial 
care  must  be  taken  that  its  lowest  level  is  flush 
with  the  floor  of  the  smus  (see  Fig.  914).  If  well 
executed  this  operation  establishes  free  per- 
manent drainage,  which   alone  wdll   suffice    to 


Fig. 


913. — H.  Tilley  :  Diseases  of  Throat  and  Nose. 

(H.  K.  Lewis.) 

induce  the  chronically  inflamed  mucous  mem- 
brane to  return  to  its  normal  condition.  No 
after  treatment  will  be  necessary  beyond  irri- 
gating the  nasal  cavity  twice  daily  with  a 
warm  alkaline  lotion  for  a  fortnight  or  three 
weeks. 


685 


The  large  majority  of  chronic  empyemata 
may  be  cured  in  this  way.  Occasionally,  how- 
ever, when  the  nasal  passages  are  so  narrowed 
by  septal  or  other  obstructions  that  free  access 
to  the  inner  wall  of  the  sinus  camiot  be  gained, 
or  «hen   mucous   membrane  hypertrophies  or 


Fig.  914. 

polypi  are  present  it  may  be   wise  to  perform 
the  Caldwell-Luc  operation. 

Operation. — The  anterior  half  of  the  inferior 
turbinal  is  first  removed  and  an  incision  is 
then  made  over  the  canine  fossa  in  the  gingivo- 
labial  groove,  the    soft    parts  and  periosteum 


Fn:.  01.5. 

are  turned  up,  and  the  canine  fossa  is  freely 
opened  with  chisel  and  mallet,  or  trephine  (see 
Fig.  915).  The  sinus  is  carefully  inspected,  and 
only  diseased  mucous  membrane  curetted  away. 
By  means  of  suitable  forceps  the  inner  wall 
is  next  removed,  together  with  any  diseased 
ethmoidal  cells.  When  bleeding  has  been 
checked  the  buccal  wound  is  sutured. 


After  three  to  four  days  spent  in  bed,  or  at 
least  indoors,  intra-nasal  irrigation  witli  a  \\arm 
alkaline  antiseptic  lotion  should  be  carried  out 
for  a  month,  after  which  no  local  treatment  is, 
as  a  rule,  necessary. 

Other  operations,  Ijased  on  the  principle  of 
free  intra-nasal  drainage,  have  been  suggested 
by  various  rhinologists,  e.  g.  Onodi  (Buda- 
Pesth)  advises  the  removal  of  only  the  membran- 
ous parts  of  tlie  middle  meatus,  and  follows  this 
with  syringing  for  ten  days  to  a  fortnight. 

Denker's  method  is  still  more  radical  than 
any  of  the  foregoing  operations,  its  essential 
feature  being  the  removal  of  the  ascending 
process  of  the  maxillary  bone. 

One  mentions  the  Dessault-Kiister  operation 
only  to  condemn  it.  A  large  opening  is  made 
in  the  canine  fossa,  and  through  this  the  sinus 
is  frequently  packed  « ith  a  wick  of  gauze.  The 
treatment  may  last  for  months,  it  is  painful, 
tedious,  and  uncertain,  and  fulfils  none  of  the 
cardinal  principles  of  free  drainage,  which  are 
alone  essential  to  success. 

Conclusions 

The  writer  has  endeavoured  to  emphasize 
the  following  facts — 

1.  Empyema  of  the  maxillary  sinus  is  more 

commonly  due  to  intra-nasal  than  to 
dental  infection. 

2.  A  tooth  with  a  living  pulp  never  causes 

suppuration  of  the  sinus. 

3.  Pyorrhoea  alveolaris  around  a  living  tooth 

may  induce  empyema. 

4.  The  prognosis  in  dental  infection  is  better 

than  when  infection  enters  the  sinus 
by  way  of  the  nose  in  acute  specific 
fevers. 

5.  A  sound  or  even  useful  tooth  should  never 

lie  removed  for  diagnostic  j)urposes — 
in  cases  of  doubt  intra-nasal  puncture 
will  always  determine  the  presence  or 
absence  of  pus  in  the  sinus. 

6.  Alveolar  drainage  should  be  reserved  only 

for  acute  empyemata  of  dental  origin, 
or  for  a  chronic  empyema  occurring  in 
old,  feeble,  or  exhausted  patients. 

7.  Intra-nasal  drainage  is  indicated  in  acute 

empyema  of  nasal  origin,  that  does  not 
ciu-e  by  repeated  irrigation,  and  in  all 
cases  of  chronic  suppuration  of  dental 
or  nasal  origin. 

H.T. 

BIBLIOGRAPHY 

(1)  CoAKLEY,  G.   (N.Y.).     Diseases  of  the  Nose  and 

Throat,    1905. 

(2)  Fraser.     Jour.  Laryngology,  Sept.  1909. 

(3)  GoETJES.     Arch.  f.  Laryngol,  Band  XXII,  H.   I. 

(4)  Grunw.\i.d.     Nasal  Suppurations,  Munich,  1900. 

(English  translation  by  Lamb.) 


686 


(5)  Grunwald,  Lack,  TiLLEY,  and  Lermoyez.     Brit. 

Med.  Jour.,  1902,  Vol.  II,  p.  595. 

(6)  Hajek.     Pathologie    utid    Therapie    der    entzund- 

lichen  Erkrankungen  der  Nebenhohlen  der  Naae, 
Wien,  1909. 

(7)  KiixiAN.     Hey  matin's  Handbuch. 

(8)  KrLLiAN  and  Schaeffer.     Heymanns  Handbuch 

der    Laryngologie    und    Rhinologic,    Band    III, 
Wien,  1899. 

(9)  Lack,  Lambert.     Diseases  of  the  Nose,  1906. 

(10)  Lewis  and  Turner.     Edin.  Med.  Jour.  1905. 

(11)  LiNDBNTHAiS.      Wiener     Klin.    Wochens.     1897, 

No.    15. 

(12)  Luc,  H.     Lerons  sur  les  suppurations  de  Voreille 

moyenne    et    des    cavitt's    accessoires    des    fosses 
nasales.   Paris,    1896. 


(13)  Onodi.     Arch.  f.  Laryngologie,  Berlin,  1903. 

(14)  Oppikoffer.     Arc/(. /.  iaj-i/ngoZ.  Band  XIX,  H.  1. 

(15)  TiLLEY,   Herbert.     Lancet,    1904,    1,    pp.    1057, 

1414. 

(16)  TiLLEY,  Herbert.     Brit.  Med.  Jour.,  1905,  1906 

and  1907. 

(17)  TiLLEY,    Herbert.     Diseases    of    the    Nose    and 

Throat,   1907. 

(18)  TiLLEY,    Herbert.     Diseases    of    the    Accessory 

Sinuses  of  the  Nose.    System  of  Medicine,  1909, 
Allbutt  and  Rolleston. 

(19)  Turner,   Logan.     The  Accessory  Sinuses  of  the 

Nose.     Edin.  1901. 

(20)  ZiEM.     Monats.  f.  Ohrenheilkunde,  1885,  S.  376. 

(21)  Zuckerkanbl.     Normale  und  pathologische  Ana- 

tomic,  Band   II,    1892. 


CHAPTER  XLIV 

NECROSIS    OF    THE   JAW 


Necrosis  of  the  Jaw  may  be  due  to  drugs, 
trauma,  or  some  germ  infection. 

DRUG    NECROSIS 

may  be  due  to  arsenious  acid  or  phosphorus, 
possibly  also  to  a  violent  use  of  escharotics. 
Mercurial  necrosis  is  classed  as  septic. 

Arsenic  Necrosis  generally  occurs  as  a  result 
of  some  accident  or  idiosyncrasy  during  the 
use  of  arsenious  o.xide  to  devitaUze  a  pulp. 
It  occurs  accidentally  when  the  drug  leaks  out 
from  under  a  temporary  filling,  or  is  displaced 
at  the  time  of  its  insertion.  The  accident  may 
be  prevented  by  placing  a  metal  cap  over 
the  drug  before  inserting  the  filling.  As  an 
idiosyncrasy  it  occurs  as  a  result  of  the  spread 
of  inflammation  through  the  apex  of  the  tooth, 
perhaps  easiest  of  occurrence  when  the  tooth 
is  yet  young  and  the  apex  wide  open.  Chemical 
examination  of  a  large  number  of  pulps  devital- 
ized by  arsenic  shows  that  the  drug  itself  does 
not  travel.  The  resulting  necrosis  may  be  of 
considerable  size ;  its  course  may  be  acute  or 
chronic. 

Phosphorus  Necrosis  occurs  in  match-workers 
using  the  yellow  form  of  phosphorus,  probably 
on  account  of  its  ready  oxidation.  The  phos- 
phorus fumes,  probably  the  oxide,  gain  access 
through  lesions  of  the  gums  or  alveolar  bone 
due  to  tartar,  pyorrhoea,  or  septic  teeth.  Ab- 
sorption through  the  alimentary  or  respiratory 
tract  may  aid  the  process  by  lowering  the  general 
vitality.  The  disease  is  probably  partly  septic 
in  origin.  The  necrosis  is  generally  of  a  chronic 
type  and  may  slowly  progress  till  the  whole 
bone  is  killed.  The  mandible  is  its  more 
frequent  seat.  Owing  to  the  slow  progress  of 
the  disease,  the  necrotic  part  of  the  mandible 
becomes  enclosed  in  a  shell  of  new  bone  of 
porous  nature  resembling  pumice-stone,  with 
blood  systems  running  at  right  angles  to  the 
surface,  said  to  be  peculiar  to  phosphorus 
necrosis. 

TRAUMATIC  NECROSIS 

pure  and  simple  occurs  as  a  result  of  entire 
destruction  of  blood-supply,  both  internal  and 
external.  It  is  seen  most  frequently  in  the 
small  fragments  of  bones  broken  from  the  main 
portions  in  cases  of  fracture  of  the  mandible,  or 

68 


from  the  alveolus  during  extraction.  In  these 
cases  the  blood  sujjply  is  entirely  cut  off  at  the 
time  of  injury.  Li  other  cases  jmrt  of  the 
blood-supply  is  cut  off  at  the  time  of  the 
accident,  the  rest  secondarily  by  the  intensity 
of  the  subsequent  inflammation.  It  is  rare, 
however,  that  these  cases  are  purely  traumatic  ; 
subsequent  inflammation  is  generally  aggrav- 
ated by  sepsis.  Wliere  great  force  has  been 
exerted  in  extraction,  as  in  the  case  of  a  third 
lower  molar,  subsequent  necrosis — partly  trau- 
matic, partly  septic — is  to  be  expected. 

INFECTIVE  NECROSIS 

is  the  pathological  sequence  of  infective 
osteitis  and  periostitis.  It  includes  necrosis 
following  alveolar  abscess,  some  cases  of  ne- 
crosis following  extraction,  necrosis  complicat- 
ing ulcerative  stomatitis,  necrosis  of  cancrum 
oris,  necrosis  complicating  pyorrhoea,  necrosis 
complicating  specific  fevers  and  some  general 
diseases,  mercurial  necrosis,  syphilitic  necrosis, 
tubercular  necrosis  and  actinomycotic  necro- 
sis. Necrosis  may  occur  in  the  course  of  an 
epitheliomatous  growth  of  the  jaw. 

As  a  subclass  of  infective  necrosis,  necrosis 
complicating  alveolar  abscess,  extraction,  ulcera- 
tive stomatitis,  cancrum  oris,  pyorrhoea,  specific 
fevers  and  some  general  diseases,  and  mercurial- 
ism,  may  be  grouped  as  "  septic  ". 

In  the  case  of  alveolar  abscess,  necrosis  is  to 
be  suspected  when  there  are  unduly  prolonged 
inflammatory  symptoms  after  subsidence  of  the 
acute  dental  abscess ;  sometimes  necrosis  seems 
to  be  determined  by  the  extent  of  the  sub- 
periosteal pus  accumulation,  but  it  is  remark- 
able how  large  an  area  of  bone  may  thus  be 
laid  bare  without  subsequent  necrosis.  The 
actual  necrotic  process  is  generally  acute,  the 
necrosed  part  of  small  size,  comprising  a  portion 
of  one  or  other  alveolar  -wall ;  rarely  the  necrosis 
includes  the  whole  depth  of  the  mandible. 

Septic  necrosis  following  extraction  wHl  be 
rare  if  both  instruments  and  teeth  (especially 
the  neck)  are  clean,  and  if  care  has  been  taken 
to  insert  the  blades  of  the  forceps  between  the 
bone  and  the  tooth.  In  view,  however,  of  the 
septic  nature  of  teeth  in  general,  its  occurrence  is 
to  be  expected  occasionally,  particularly  when 
great    violence    has    been   used    in   extraction. 


688 


or  in  an  undrainable  position  after  the  use  of  i 
local  anaesthesia,  e.  g.  a  third  lower  molar. 
The  use  of  local  injections  favours  the  occur- 
rence of  a  septic  socket  by  depressing  the  vitality 
of  the  tissues  and  so  retarding  the  healing 
processes ;  and  ■^^■hen  the  injection  contains 
suprarenal  extract,  by  preventing  bleeding,  and 
thus  depriving  the  socket  of  its  normal  plug — a 
clean  blood-clot — and  leaving  it  open  for  in- 
fection. The  disease  generally  begins  as  a 
septic  socket,  i.  e.  as  an  infective  osteitis,  and 
causes  in  acute  cases  a  persistent  toothache 
as  bad  as,  or  worse  than,  the  original  pain.  The 
bone  is  extremely  tender,  and  though  the 
whole  tooth  has  been  removed  the  socket  refuses 
to  heal ;  the  soft  tissues  round  its  orifice  are 
acutely  tender  and  oedematous,  bare  bone  is 
found  on  probing,  and  eventually  there  is  a  dis- 
charge of  pus.  Treatment  consists  in  thorough 
syringing  and  sponging  out  of  the  socket  at 
least  twice  a  day  and  Hght  packing  with  cya- 
nide or  sal-alembroth  gauze  till  the  osteitis 
clears  up  or  a  necrotic  fragment  separates. 

Necrosis  complicating  ulcerative  stomatitis  is 
a  not  uncommon  event.  It  is  more  frequent 
in  childhood,  but  is  seen  also  in  adults.  It  may 
include  a  large  piece  of  the  jaw,  or  only  the 
layer  of  bone  immediately  surrounding  the 
root.  The  inflammation  is  probably  never 
unmixed,  even  supposing  the  disease,  ulcerative 
stomatitis,  to  have  started  as  a  simple  infection, 
since  the  chances  of  mixed  infection  are  almost 
overwhelming.  In  childhood  the  developing 
permanent  teeth  are  liable  to  injury  or  complete 
destruction. 

Necrosis  complicating  cancrum  oris  becomes-  a 
serious  matter,  owing  to  sepsis,  when  the  patient 
is  past  the  acute  stage  and  on  the  way  to  a 
possible  recovery.  It  is  probably  present  in 
every  case  of  cancrum  oris. 

Necrosis  complicating  pyorrhoea  is  not 
common.  Sections  of  decalcified  pyorrhoeic 
jaws  seem  to  show  niinut*  necrotic  fragments 
of  alveolar  bone  around  the  affected  teeth,  but 
it  is  questionable  whether  these  fragments  are 
more  than  remnants  of  an  irregularly  ulcerated 
socket.  Acute  necrosis  of  the  jaw  may  compli- 
cate pyorrhoea,  and  is  generally  merely  labelled 
I'acute  necrosis  ","  acute  septic  necrosis '",  or 
"  acute  osteomyelitis ".  The  importance  of 
recognizing  its  origin  lies  in  the  fact  that  by  due 
attention  to  the  pyorrhoea  the  disease  may  be 
prevented.  The  disease  may  extend  to"  the 
whole  body  of  the  jaw. 

In  rare  cases  chronic  necrosis  complicates 
pyorrhoea  and  slowly  spreads  through  the 
cancellous  body  of  the  bone,  preceded  by  a 
central  formative  osteitis,  and  accompanied  in 
the  mandible  by  extensive  deposit  of  perio.steal 
new  bone.  Such  general  enlargement  of  the 
bone  may  lead  to  a  suspicion  of  acromegaly. 


The  course  of  the  disease  is  generally  acute, 
though  sometimes  chronic,  and  its  symptoms 
and  pathology  are  similar  to  those  of  necrosis 
elsewhere.  Special  symptoms  of  necrosis  of 
the  jaw  are  those  due  to  the  presence  of  teeth, 
such  as  toothache,  discharge  from  the  sockets  of 
the  teeth,  loosening  and  falling  out  of  the  teeth. 
In  the  mandible  new  periosteal  bone  is  formed, 
in  the  maxilla  after  early  life  none.  In  un- 
drained  cases  foetor  is  very  bad.  In  cases  of 
acute  necrosis  the  bone  is  dead  before  the 
diagnosis  is  made,  what  is  seen  is  the  process 
of  separation.  In  chronic  necrosis  it  is  possible 
to  mark  the  slow  spread  of  the  disease.  In  all 
cases  in  childhood  injury  to  the  teeth  of  succes- 
sion is  to  be  feared. 

Necrosis  comjjlicating  specific  fevers — scarlet 
fever,  measles,  typhoid,  etc. — is  generally  of 
septic  origin.  W.  Hunter  (2)  has  shown  that 
attention  to  oral  hygiene  almost  entirely 
banishes  such  complications  of  specific  fevers  as 
cellulitis,  necrosis  of  jaw,  etc.  In  the  case  of 
typhoid  fever,  bacillus  typhosus  has  been  found 
in  pure  culture  in  bone  abscess  of  other  parts. 
Hence  it  is  possible  that  necrosis  of  the  jaw 
may  in  this  disease  be  due  to  typhoid  infection, 
but  in  general  necrosis  complicating  a  specific 
fever  is  of  septic  origin. 

Mercurial  Necrosis  is  a  septic  necrosis  occur- 
ring in  tissues  weakened  in  resistance  by  over- 
dose of  mercury.  It  presents  the  usual  symp- 
toms of  acute  or  subacute  necrosis  with,  in 
addition,  the  excessive  salivation  of  mercurial- 
ism,  and  perhaps  a  more  severe  general 
stomatitis.  It  can  be  entirely  prevented  by 
local  cleanliness. 

NECROSIS  OF   SOME   GENERAL   DISEASES 

Tabetic  and  Diabetic  Necrosis  of  the  jaw 
have  been  described.  Such  cases  are  of  septic 
origin,  probably  pyorrhoeic,  the  diseased  tissues 
furnishing  a  soil  of  lowered  resistance.  As  with 
perforating  ulcer  of  the  foot,  painlessness  and 
chronicity  may  characterize  the  jaw  necrosis 
of  tabes.  Dryness  of  the  mouth  may  be  found 
in  that  occurring  during  diabetes.  Cleanliness 
and  avoidance  of  injury  will  prevent  its  occur- 
rence in  either  case. 

Syphilitic  Necrosis  of  the  jaw  occurs  as  the 
result  both  of  acquired  and  congenital  syphilis. 
It  is  more  frequent  in  the  upper  than  the  lower 
jaw.  It  is  a  late  or  tertiary  symptom,  and 
hence  is  asymmetrical.  In  the  hard  palate  it 
not  infrequently  results  in  perforation  through 
the  nasal  floor — a  so-called  acquired  cleft. 
Its  irregularity  of  position  and  shape  dis- 
tinguishes it  from  true  congenital  cleft  palate. 
In  some  cases  the  necrotic  process  extends  to 
the  whole  of  the  hard  and  soft  palates  and  a 
large   portion   of  the   bony  framework  of  the 


689 


nose,  making  one  huge  chasm  of  mouth,  nose, 
and  naso-pharynx.  Although  the  disease  is 
a  true  syphilitic  necrosis  its  inception  is  not 
independent  of  sepsis.  In  a  syphilitic  person 
any  injury  may  determine  the  site  of  a  gum- 
matous process,  and  in  such  persons  a  septic 
inflammation  or  ulceration  of  the  gums  will 
determine  the  locality  of  the  syphilitic  lesion. 
CUnically  it  has  been  found  that  attention  to 
mouth  cleanliness  diminishes  the  incidence  of 
syphilitic  mouth  lesions. 

Tubercular  Necrosis  of  the  jaws  is  an  un- 
common disease,  and  appears  to  be  found  more 
often  in  children.  It  has  been  asserted  that 
the  tubercle  bacillus  is  an  active  agent  in  phos- 
phorus necrosis  of  the  jaw.  Infection  probably 
takes  place  through  a  local  lesion,  and  may  follow 
too  extensive  extraction  in  tubercular  subjects. 
The  di.sease  is  chronic  in  all  its  stages  and 
generally  shows  little  tendency  to  become 
arrested.  It  is  accompanied  in  its  later  stages 
by  the  secondary  septic  infection  common  to 
jaw  necrosis. 

Necrosis  may  accompany  actinomycotic  infec- 
tion of  the  jaws  (see  Chapter  LI). 

In  necrosis,  from  whatever  cause  arising,  the 
natural  forces  may  be  unequal  to  limiting 
the  process.  In  diabetes,  and  perhajjs  tabes,  the 
tissues  may  be  of  such  low  vitality  as  to  succumb 
to  very  slight  injury ;  or,  as  in  necrosis  of  can- 
crum  oris  following  specific  fevers,  that  is  in 
debilitated  subjects,  the  mechanism  of  the  re- 
sistance may  have  broken  down.  The  dangers 
of  necrosis  lie,  at  the  beginning,  in  the  possibility 
of  wide  sjjread  of  the  disease,  and  later,  during 
the  period  of  demarcation,  in  the  risks  of  septic 
poisoning. 

TREATMENT 

Where  possible  the  source  of  infection  must 
be  removed,  and  in  acute  cases  tension  reheved. 
Removal  of  teeth  will  sometimes  attain  both 
ends.  Early  extraction  and  early  evacuation  of 
pus  tend  to  limit  the  spread  of  the  disease, 
especially  in  acute  spreading  osteitis  of  pyor- 
rhoea. When  necrosis  has  been  acute  it  is  best 
to  wait  till  the  dead  25art  is  defuied  and  loose 
before  attempting  removal. 

In  the  meantime  free  drainage  must  be 
secured  and  the  mouth  and  diseased  parts  kept 
thoroughly  clean.  In  necrosis  of  the  whole 
depth  of  the  mandible  it  may  be  an  advantage 


to  make  a  dependent  drain  by  cutting  on  to 
the  diseased  part  along  the  lower  border  of  the 
bone  and  packing  to  establish  an  artificial 
sinus  (1).  X-rays  will  help  in  deciding  the 
extent  of  the  necrosis,  by  more  readily  pene- 
trating the  region  of  rarefying  osteitis  round  the 
sequestrum. 

Since  in  the  mandible  new  periosteal  bone  is 
to  be  hoped  for,  it  is  well  to  wait  before  re- 
moving the  sequestrum  till  a  strong  shell  has 
formed,  the  sequestrum  meanwhile  acting  as  a 
splint.  Sometimes  early  removal  of  the  seques- 
trum is  jjossible  and  called  for ;  the  shape  of  the 
jaw  may  then  be  partly  maintained  by  means  of 
a  simple  length  of  steel  or  silver  wire,  each 
end  of  «  hich  is  forced  into  the  bone  ;  or  a  more 
elaborate  internal  splint  may  be  possible  which 
^\Ul  prevent  the  ]:)eriosteum  falling  in  and  so 
keep  the  jaw  at  its  normal  size.  Wlien  new- 
bone  is  strong  enough  the  splint  is  removed. 
In  dealing  with  such  cases  it  must  be  remem- 
bered that  part  of  the  periosteum  may  have 
been  destroyed  by  the  initial  violence  of  the 
disease.  When  this  becomes  apparent,  more 
elaborate  and  permanent  splints  must  be  used, 
if  the  remaining  bone  is  to  be  kept  in  normal 
relation  to  the  maxilla. 

In  chronic  spreading  necrosis,  or  in  tuber- 
cular necrosis,  it  may  be  good  practice  to  operate 
before  demarcation  has  taken  place,  going  wide 
of  obvious  disease  and  taking  great  care  not  to 
reinfect  at  the  time  of  operation.  In  such  cases 
an  operation  rids  the  patient  of  a  source  of  sepsis 
that  might  otherwise  persist  indefinitely,  and  if 
the  disease  recurs  there  is  at  least  less  risk  of 
general  infection  and  septic  poisoning. 

Syphilitic  necrosis  must,  in  addition  to  local 
cleanliness  and  drainage,  be  treated  by  adminis- 
tration of  mercury  and  iodide  of  potash.  As 
a  lotion  for  general  use  for  syringing — 

B 

Sodii  Bicarb.  .  .  gr.  x. 

Acid.  Carbolic.  .  .  n\  v-x. 

Glycerini        .  .  .  5  J- 

Aq.  ad    .         .  .  .  §  j. 
M.  ft.  lot. 


J.  G.  T. 


BIBLIOGRAPHY 


(1)  Fairbank,  H.  a.  T.     Trans.   Odont.  Soc,   190.5~(), 

Vol.  XXXVIII,  p.  12. 

(2)  Hunter,  William.     Brit.  Med.  Jour. 


CHAPTER  XLY 

FRACTURES   AND   DISLOCATION    OF   THE   JAWS 


FRACTURES 

The  treatment  of  fractures  of  the  jaws,  by 
reason  of  the  employment  of  various  mechanical 
devices,  is  usually  considered  to  come  within 
the  province  of  the  dental  surgeon.  As  the 
conditions  determining  the  kind  of  injury,  the 
process  of  repair,  and  the  method  of  treatment, 
are  different  in  the  case  of  the  mandible  and 
the  maxilla,  it  will  be  convenient  to  consider 
them  separately. 

I.— MANDIBLE 

Causes. — Fracture  of  the  mandible  is  much 
more  common  than  fracture  of  the  maxilla  on 
account  chiefly  of  its  exposed  position  and 
consequent  liability  to  direct  violence.  The 
looseness  of  its  attachment  and  the  density 
of  its  structure  are  also  said  to  be  predisposing 
causes,  but  one  would  expect  that  both  these 
conditions  would  rather  be  protective ;  it  is, 
however,  of  narrow  calibre  and  roughly  in  the 
form  of  an  arch,  so  that  a  blow  on  the  most 
prominent  part  of  the  chin  would  tend  to 
spread  the  arch  and  fracture  the  bone  at  a 
weak  spot.  Furthermore  the  strength  of  the 
bone  is  much  diminished  by  the  insertion  of 
the  roots  of  the  teeth. 

Fracture  is  almost  always  caused  by  direct 
violence,  such  as  a  kick,  blow,  fall  or  gunshot 
wound.  Blows  received  in  fighting  and  kicks 
from  horses  are  among  the  most  frequent 
causes.  Extraction  of  a  tooth  is  sometimes 
accompanied  by  fracture  of  a  small  part  of  the 
alveolus.  This  is  usually  of  little  consequence, 
and  the  result  is  simp"ly  that  the  fractured 
portion  exfoliates  instead  of  becoming  absorbed. 
A  more  extensive  fracture  involving  a  consider- 
able portion  of  the  alveolus  and  the  included 
teeth  has,  however,  sometimes  occurred,  and 
there  is  always  a  danger  of  this  when  faulty 
methods  of  extraction  are  employed.  Accord- 
ing to  Heath  (7)  fracture  of  the  neck  of  the 
condyle  is  always  caused  by  a  fall  from  a 
considerable  height;  a  case  is  recorded  by  Sir 
A.  Pearce  Gould  (6)  in  which  tliis  injury  was 
caused  by  the  patient  being  violently  thrown 
from  a  dogcart  and  falling  on  the  chin. 

Position. — The  site  of  the  fracture  is  usually 
in  the  horizontal  ramus.  This  part  of  the  bone 
is,  as  has  been  explained,  near  to  the  centre  of 


the  arch,  and  it  is  less  well  protected  by  the  soft 
parts,  which  diminish  the  intensity  of  the  blow. 
The  commonest  position  is  through  the  socket 
of  the  canine  tooth  because,  on  account  of  the 
length  of  the  root,  the  bone  is  weakest  at  that 
spot.      The  next   most  frequent   positions  are 


Fig.  916. — Donlile  Fracture  with  much  displacement. 
Case  recorded  by  Malgaigne. 
(Heath  :  Injuries  and  Diseases  of  the  Jaws.) 

at  the  symphysis,  in  the  region  of  the  mental 
foramen,  and  just  in  front  of  the  angle.  Frac- 
tures of  the  ascending  ramus  can  only  be  the 
result  of  considerable  direct  violence,  e.  g.  being 
run  over  by  a  vehicle ;  weak  spots  that  are 
occasionally  the  site  of  fracture  are  the  neck 


Fig.  917. — Oblique  Fracture  at  Symphysis.  Fracture 
of  Coronoid  Process,  and  Fracture  at  Neck  of 
each  Condyle.  From  Sir  William  Fergusson's 
"  Practical  Surgery  ". 

{Heath  :  Injuries  and  Diseases  of  the  Jaws.) 

of  the  condyle  and  some  part  of  the  coronoid 
process  (see  Figs.  916,  917). 

Varieties. — Except  in  the  case  of  the  symphysis 
in  young  persons,  the  line  of  fracture  in  the 
horizontal  ramus  usually  departs  somewhat 
from  the  vertical,  and  there  is  also  obliquity 
through    the   thickness   of    the   bone,    accom- 


690 


691 


panied  by  overlapping  of  the  fractured  ends, 
the  obhquity  being  at  the  expense  of  the  outer 
plate  of  the  larger  anterior  fragment  (see  Fig. 
918).  This  obliquity  is,  however,  occasionally 
in  the  reverse  direction,  being  at  the  expense  of 
the  inner  jjlate  of  the  anterior  fragment.  In 
the  case  of  double  fracture  the  obliquity  is 
usually  similar  on  the  two  sides,  the  centre 
fragment  being  smaller  externally  than  intern- 
ally ;  but  occasionally  the  obhquity  is  different 
on  the  two  sides  and  there  is  consequently  some 
difficulty  in  reducmg  the  fracture  and  main- 
taining apposition  of  the  fragments.  The 
liability  of  the  fracture  to  be  compound  de- 
pends almost  entirely  on  the  site  of  the  fracture. 
In  the  case  of  the  horizontal  ramus  the  gum  is  so 
closely  attached  that  it  is  the  general  rule  for 
fractures  to  be  compound  towards  the  mouth, 
but  the  ascending  ramus  is  sufficiently  deeply  em- 
bedded to  jjrevent  this  complication.     Fractures 


Fic.  918. 

are  usually  simple,  but  they  may  be  multiiale,  or 
even  comminuted,  as  for  example  in  gunshot 
injuries,  in  which  there  may  be  much  destruc- 
tion and  loss  of  bone  tissue.  A  somewhat 
remarkable  case  of  gunshot  injury  in  which 
much  new  bone  was  deposited  is  recorded  by 
Marshall  (10). 

Signs  and  Symptoms. — The  diagnosis  of  frac- 
ture of  the  horizontal  ramus  is  usually  easy, 
but  in  the  case  of  the  ascending  ramus  some- 
what obscure.  The  signs  and  symptoms  of 
fracture  are  partly  common  to  those  of  fracture 
of  other  bones  and  partly  peculiar  to  this  bone. 
Crepitus  can  generally  be  obtained  easily  except 
in  the  case  of  the  more  remote  portions  of  the 
ascending  ramus,  but  even  then  it  can  generally 
be  obtained  by  placing  the  fingers  of  one  hand 
weU  back  inside  the  mouth  and  the  other  hand 
outside.  The  patient  wlU  usually  be  conscious 
of  shght  crepitus  on  pressing  the  jaws  together, 
and  often  supports  the  jaw  with  the  hand  to 


prevent  pain  from  movement.  There  is  an 
unnatural  mobility  of  the  bone  independent 
of  its  normal  movement  at  the  condyle,  but 
the  degree  of  mobility  depends  upon  the  site 
of  the  fracture.  If  there  is  much  displacement 
a  want  of  symmetry  of  the  face  is  observable, 
but  this  sign  may  be  obscured  by  the  consider- 
able amount  of  swelling  that  always  accom- 
panies fracture.  The  most  certain  indication 
of  displacement  is  therefore  afforded  by  irregu- 
larity in  the  line  of  the  teeth,  but  the  line  of 
the  necks  of  the  teeth  should  be  observed, 
because  variations  in  the  length  of  the  teeth 
frequently  occur  from  loss  of  opposing  teeth 
in  the  maxilla.  It  is  only  when  fracture  occurs 
in  the  anterior  portion  of  the  horizontal  ramus 
that  mobihty  and  displacement  are  at  all 
considerable.  The  normal  movement  of  the 
jaw  is  much  restricted,  partly  by  the  separation 
of  the  bone  and  partly  by  the  effusion.  If 
there  is  much  displacement  the  patient  may 
not  be  able  to  close  the  mouth  completely ;  if 
the  fracture  is  in  the  ascending  ramus  or  at 
the  neck  of  the  condyle  he  may  find  difficulty 
in  opening  the  mouth.  Fracture  causes  con- 
siderable pain,  usually  referred  to  the  position 
of  the  fracture,  and  there  is  great  tenderness  at 
the  same  spot.  Colyer  (5)  states  that  in  cases 
of  fracture  about  the  angle  pain  is  often  referred 
to  the  third  molar  or  mandibular  foramen.  As 
in  the  case  of  most  mouth  injuries,  salivation  is 
excessive.  Li  case  of  difficulty  in  diagnosis  a 
radiograph  will  often  solve  the  problem. 

Displacement. — The  character  and  direction 
of  the  displacement  vary  according  to  the  site 
of  the  fracture  and  the  direction  of  the  force, 
and  are  influenced  by  muscular  action,  gravity, 
and  interlocking  of  the  fractured  ends.  In 
the  case  of  the  most  common  fracture  in  the 
region  of  the  canine  or  first  premolar  socket, 
the  larger  anterior  fragment  is  drawn  down- 
wards and  backwards  by  the  digastric,  genio- 
hyoid and  genio-hyo-glossus  muscles,  and  by 
gravity ;  the  smaller  fragment  is  chawn  upwards 
and  slightly  forwards,  and  the  lower  border  is 
slightly  everted  by  the  action  of  the  masseter 
and  temporal  muscles  of  that  side,  so  that  the 
smaller  fragment  overlaps  the  greater  anterior. 
This  overlapping  is  also  promoted,  when  the 
fracture  is  oblique,  by  the  action  of  the  external 
pterygoids  which  draw  each  fragment  forwards 
and  inwards.  In  case  of  a  double  fracture  of 
this  kind,  separating  the  jaw  into  three  parts, 
the  depression  of  the  centre  fragment  is  well 
marked. 

When  fracture  occurs  about  the  angle  the 
posterior  fragment  is  drawn  upwards  by  the 
temporal  muscle,  and  the  anterior  fragment 
tilted  dowai wards  by  the  depression  of  the  chin. 
Each  fragment  is  drawn  inwards  by  the  external 
pterygoids  as  before. 


692 


Wlien  the  fracture  is  in  the  horizontal  ramus 
jjosterior  to  the  anterior  border  of  the  masseter, 
or  in  the  ascending  ramus,  the  envelopment  of 
tlie  masseter  and  internal  pterygoid  muscles 
prevents  much  disjDlacement ;  but  in  fractures 
across  the  upper  part  of  the  ascending  ramus, 
or  in  the  rare  cases  of  fracture  across  some  part 
of  the  coronoid  process,  the  upper  fragment  is 
drawn  upward  and  backwards  by  the  temporal 
muscle.  In  tlie  rare  cases  where  fracture  occurs 
across  the  neck  of  tlie  condyle,  the  condyle 
itself  is  drawn  forwards  by  the  external  ptery- 
goid, and  the  chin  is  deflected  a  little  towards 
the  affected  side,  differing  in  this  respect  from 
what  happens  in  the  case  of  unilateral  disloca- 
tion. 

Complications. — These  may  be  divided  into 
two  classes,  those  immediately  connected  with. 
tlie  accident  and  those  that  may  develop  during 
the  period  of  repair.  Among  the  former  are 
injuries  to  the  soft  parts,  liaemorrhage  (capillary 
or  even  arterial),  injury  to  the  inferior  alveolar 
nerve,  fracture  or  dislocation  of  the  teeth, 
injury  to  the  base  of  the  skull,  and  dislocation 
of  the  condyle.  Among  the  latter  are  damage 
to  the  inferior  alveolar  nerve  by  inclusion  in 
callus,  abscesses  pointing  in  the  neck,  and 
necrosis  of  the  fractured  ends  or  larger  portions 
of  bone.  The  inferior  alveolar  artery  is  not  usu- 
ally torn.  Injury  to  the  inferior  alveolar  nerve 
only  occurs  in  the  less  frequent  cases  of  fracture 
behind  the  mandibular  foramen,  and  causes 
loss  of  sensation  in  the  skin  over  the  parts  of 
the  chin  and  lower  lip  supplied  by  it,  or  neuralgic 
pains  in  the  course  of  the  nerve.  Cases  are 
recorded  by  Dencer  Wliittles  (17).  This  com- 
plication is  rare,  and  only  temporary ;  it  would 
only  be  permanent  in  the  case  of  much  damage 
to  the  nerve.  Necrosis  of  small  portions  of 
bone  is  not  infrequent,  and  is  not  of  much 
consequence,  but  sometimes,  especially  in  the 
case  of  comminuted  fracture,  large  portions 
necrose  and  cause  very  great  deformity.  Dis- 
location associated  with  fracture  of  the  hori- 
zontal ramus  is  very  rare  according  to  Heath  (7). 
It  has  occasionally  happened  in  connection  with 
fracture  of  the  neck  of  the  condyle.  The  dis- 
location must  be  reduced  before  the  fracture 
is  dealt  with.  A  case  of  deafness  foUowmg 
fracture  of  both  condyloid  processes  is  recorded 
by  Dencer  Wliittles  (17).  Rarely  a  salivary 
fistula  may  supervene  as  the  result  of  a  fracture 
compound  externally,  or  of  a  subsequent 
abscess  pointing  in  the  neck.  There  is  as  a 
rule  a  very  septic  condition  of  the  mouth 
associated  with  fractured  mandible,  probably 
on  account  of  restricted  movement  of  the  parts 
and  stagnation  of  oral  fluids. 

Prognosis. — Owing  to  the  vascularity  of  the 
bone,  repair  and  reunion  take  place  fairly 
easily,  but  by  reason  of  the  functions  of  the 


bone,  rest  with  the  fragments  in  correct  apposi- 
tion is  difficult  to  ensure,  especially  in  the  case 
of  double  fracture.  Union  takes  place  gener- 
ally in  from  tliree  to  six  weeks,  but  may  be 
delayed  by  peculiar  difficulties  of  treatment, 
necrosis  of  the  ends,  or  the  inclusion  of  a  tooth 
or  other  foreign  body  between  them ;  when 
bony  union  fails  the  result  will  be  either  a 
fairly  satisfactory  fibrous  union,  or  a  false 
joint,  which  in  the  horizontal  ramus  is  a  serious 
impediment  to  mastication,  but  is  of  less  con- 
sequence in  the  ascending  ramus. 

Treatment  of  Fracture  of  the  Horizontal  Ramus 

The  simplest  method  of  treatment  consists 
in  the  application  of  a  four-tail  bandage  (see 
Fig.  919),  with  or  without  a  gutta-percha  chin- 
cap.     As  a  temporary  measure  this  is  useful. 


Fig.  919.— Four-tail  Bandage. 
(He.\th  :   Injuries  and  Diseases  oj  the  Jaws.) 

but  it  is  not  generally  good  permanent  treat- 
ment, unless  there  is  no  displacement  of  the 
fragments  :  the  disadvantages  of  the  bandage 
are  that  the  lower  jaw  is  bound  firmly  to  the 
upper  jaw,  which  in  fact  acts  as  the  spUnt, 
and  feeding  is  difficult  or  impossible ;  also  that 
displacement  is  not  remedied,  but  rather 
increased  by  the  pressure  applied.  This  in- 
crease, or  at  least  want  of  correction,  of  the 
displacement  is  caused  by  the  pressure  of  the 
bandage  being  in  too  backward  a  direction, 
that  is  to  say,  from  the  chin  to  the  occiput. 

To  remedy  this,  and  make  the  pressure  more 
vertical,  various  modifications  of  the  four-tail 
bandage  have  been  devised.  Probably  the  best 
of  them  is  Hamilton's,  which  is  composed  of 
three  straps  (see  Fig.  920).  A  firm  leather  strap 
passes  under  the  chin,  and  vertically  upwards  on 
each  side,  and  is  fixed  by  a  buckle  a  little  above 
the    forehead.     A    counter    strap    of    webbing 


693 


passes  across  the  forehead,  and  round  the  head 
above  the  ears,  and  is  fixed  below  the  occiput. 
Tlie  first  strap  passes  through  a  loop  in  this 
webbing  on  each  side  \\here  they  cross.     Another 


gums  must  be  taken  in  gutta-percha,  without 
any  attempt  being  made  to  correct  the  dis- 
placement. A  plaster  of  Paris  cast  is  made 
from  the  impression,  and  is  sawn  in  two  parts 
at  the  line  of  fracture ;  the  two  parts  are  then 
reunited  in  correct  apposition.  To  the  cast 
so  formed  a  vulcanite  or  metal  splint  can  be 
made,  which  will  fit  the  teeth  and  jaw  when 
the    displacement    is    corrected.     In    order    to 


Fig.  920. — Haniiltou  s  Strap  Support. 
(Heath  :  Injuries  and  Diseases  of  the  Jaws.) 

strap  of  webbing  passes  along  the  median  line 
of  the  head  over  the  occiput  and  ties  the  other 
two  so  as  to  prevent  slipping.  In  conjunction 
with  a  bandage  or  strap,  a  chin-cap  made  of 
gutta-percha  may  be  used ;  it  should  be 
moulded  in  warm  water  from  a  piece  of 
sheet  cut  in  the  form  shown  in  Fig.  921. 
Half  goes  under  the  chin,  and  the  other 
half  in  front,  and  the  ends  of  the  lower 
half  when  bent  upwards  overlie  the  ends 
of  the  upper  half  (see  Fig.  922).  The 
gutta-percha    should    have    holes    in    to 


Fig.  922. — Giitta-perclia  Chin-cap. 
(Heath  :  Injuries  and  Diseases  of  the  Jaivs.) 

facilitate  the  manufacture  of  the  cast  in 
imitation  of  the  broken  jaw,  it  « ill  sometimes  be 
necessary  to  take  an  impression  of  the  upper 
jaw  and  adjust  the  parts  of  the  lower  cast  to 
the  upper  cast,  using  the  occlusion  of  the 
teeth  as  a  guide. 

The  form  of  splint  most  commonly  used  is 
that  know  n  as  the  Hammond  splint  (see  Fig.  923) . 
It  consists  of  a  piece  of  stout  wire  of  soft  iron, 
silver,  or  German  silver,  fitted  closely  round  the 
labial  and  lingual  surfaces  of  the  necks  of  the 


Fig.  921. — Form  of  Guttapercha  for  moulding 
into  Chin-cap. 
(He.vth  :   Injuries  ami  Diseases  of  the  Jaws.) 

permit  evaporation,  and  be  lined  with 
chamois  leather,  and  the  skin  should  be 
dusted  over  with  boracic  powder  before 
the  splint  is  applied.  As  an  alternative 
to  the  bandage  a  small  skull-cap,  with 
attachments  to  the  chin-cap,  may  be 
used. 

Where  there  is  displacement  to  be  corrected, 
some  form  of  spUnt  within  the  mouth,  and  firmly 
attached  to  the  lower  jaw,  must  be  used.  For 
this  purpose  an  impression  of  the  teeth  and 


Fig.  923. — Hammond  Splint.     Interrupted  line  indicates  position 
of  fracture. 
(Heath:  Injuries  and  Diseases  of  the  Jaws.) 

teeth  and  behmd  the  last  tooth  on  each  side  ;  the 
ends  are  united  by  means  of  soft  solder  or  silver 
solder  as  the  case  may  be.  The  splint  is  attached 
to  the  teeth  by  means  of  fine  iron  or  brass  wire 


694 


ligatures.  Eacli  ligature  is  passed  over  the 
outer  bar,  through  the  inter-space  between  two 
teeth,  under  the  inner  bar,  and  back  over  the 
inner  bar,  through  the  next  inter-space,  and 
under  the  outer  bar.  The  two  ends  are  then 
twisted  together  so  that  one  tooth  is  completely 
encircled ;  the  ends  are  cut  short  and  then 
turned  in  so  as  not  to  scratch  the  cheek  or 
gum.  The  only  difficult  part  consists  in  catchmg 
the  end  of  the  wire  after  it  has  been  passed 
in  under  the  inner  bar,  and  threading  it  through 
on  the  return.  For  this  purpose  a  pair  of  jDliers 
may  be  used ;  if  the  fingers  are  employed  care 
must  be  taken  not  to  prick  them  with  the  wire, 
as  the  risk  of  septic  absorption  would  be  con- 
siderable. It  is  sometimes  possible  to  pass 
the  wire  between  the  crowns  of  the  teeth  instead 
of  threading  it  through  on  the  return,  where 
the  teeth  are  not  very  close  together.  These 
ligatures  must  be  applied  round  most  of  the 
teeth,  but  loose  teeth  should  be  omitted.  It 
is  important  to  ligature  all  the  teeth  in  the 
neighbourhood  of  the  fracture  except  those 
immediately  adjacent.  It  is  well  not  to  twist 
up  the  ends  of  the  ligatures  tightly  until  all 
are  in  place ;  by  this  means  the  jaw  is 
gradually  steadied  and  the  splint  \sorked 
into  position.  The  ligatures  will  probably 
want  tightening  after  a  few  days. 

The  Hammond  splint  is  in  general  the 
most  efficient  form  to  employ.  It  is  easily 
made,  fairly  easy  to  apply,  and  less  incon- 
venient to  the  patient  than  most  other 
forms ;  furthermore,  it  promotes  sepsis  to  a 
less  degree  than  those  kinds,  to  be  described, 
that  more  completely  enclose  the  teeth  and 
alveolus.  It  cannot  be  generally  used  in 
cases  where  many  of  the  teeth  have  been 
lost  from  one  or  both  fragments,  but  the 
writer  has  found  that  where  a  difficulty 
occurs  from  loss  of  the  molars  on  one 
side,  the  splint  may  still  be  used  if  the  wire 
is  carried  to  the  back  of  the  jaw,  as  if  the  teeth 
were  present,  and  the  intervening  space  filled 
with  vulcanite  to  fit  the  gum.  By  this  means 
the  splint  is  very  much  steadied  and  fixation 
to  the  remaining  teeth  is  sufficient.  H.  Lloyd 
Williams  (18)  has  devised  a  method  by  which 
the  Hammond  splint  may  be  made  applicable 
where  the  fracture  is  far  back  in  the  horizontal 
ranuis,  and  only  one  molar,  generally  the  third, 
is  in  the  smaller  fragment.  He  makes  the  wire 
fit  loosely  round  this  tooth,  and  fills  the  inter- 
vening space  with  vidcanite  to  form  a  closely 
fitting  collar  around  the  tooth.  The  Hammond 
splint  is  difficult  to  fix  where  the  teeth  are  short 
or  loose,  and  is  therefore  often  not  applicable  to 
chOdren.  It  was  largely  used  by  the  inventor 
in  the  Franco-Prussian  War. 

A  modification  of  the  Hammond  splint  for 
use  where  the  fracture  is  near  the  front  of  the 


jaw  has  been  suggested  by  Newland-Pedley  (12). 
Instead  of  carrying  the  wire  round  behind  the 
last  teeth  on  each  side,  he  passes  it  through 
from  the  lingual  aspect  between,  say,  two 
premolars  on  each  side,  and  after  adapting 
the  wire  closely  on  both  the  lingual  and  labial 
aspects,  twists  the  ends  together.  Colyer  (5) 
suggests  passing  the  ends  into  a  short  piece  of 
metal  tube. 

A  kind  of  double  Hammond  or  "  cradle  " 
splint  has  been  suggested  by  J.  Lewin  Payne 
(14)  (see  Fig.  924).  The  thick  wire  frames,  made 
of  silver,  are  adapted  to  both  upper  and  lower 
arches.  Each  wire  is  strengthened  by  pieces 
passing  across  between  the  crowns  of  the  teeth  on 
the  occlusal  aspect,  and  the  two  frames  are  united 
by  vertical  pieces.     In  cases  where  it  is  difficult 


Fit;.  924.— Payne's  Cratlle  Splint. 

(Pror.  Boy.  Soc.  oj  Med.) 

to  retain  the  fragments  in  position  with  an 
ordinary  Hammond,  additional  stability  may 
be  obtained  with  this  splint. 

The  other  forms  of  splint  all  consist  of  a 
metal  or  vulcanite  cap  to  enclose  some  or  all 
of  the  teeth.  A  cast  is  obtained  in  the 
manner  previously  described,  and  a  metal  or 
thin  vulcanite  plate  made  to  enclose  the  teeth 
and  fit  either  accurately  or  loosely.  The 
method  of  making  the  plate  is  similar  to  that 
used  in  making  artificial  dentures ;  the  metal 
plate  may  be  either  swaged,  or  cast  under 
pressure.  A  closely  fitting  cap  made  in  this 
way  is  fixed  to  the  teetJi  by  means  of  a  cement 
of  oxy-phosphate  of  zinc  or  copper,  and  it  is 
essential  that  the  teeth  should  be  thorouglily 
dried,  or  else  the  cement  will  not  adliere  properly. 
To  do  this  in  the  mouth  of  a  patient  with  a 
fractured  jaw  is  extremely  difficult,  and  the 
more  general  plan  is  to  make  the  spUnt  loosely 


695 


fitting  and  fill  the  intervening  space  with  gutta- 
percha. This  form  of  splint  is  made  by  just 
covering  the  plaster  teeth  of  the  model  with  a 
layer  of  wax,  and  then  maldng  the  splint  to 
fit  over  the  wax.  The  gutta-percha  to  fill  the 
intervening  space  in  the  mouth  should  be 
softened  in  hot  water,  then  dried,  and  pressed 
into  the  splint.  The  teeth  should  be  made 
as  dry  as  possible,  and  the  gutta-percha  in  the 
splint  warmed  gently  over  a  spirit  flame  or 
Bunsen  lamp,  and  the  splint  pressed  firmly 
into  position,  or  rather  the  two  portions  of 
the  jaw  pressed  into  the  splint  in  their  proper 
relative  position.  It  is  not  absolutely  necessary 
that  the  teeth  should  be  dry,  but  if  they  are 
the  splint  wiU  hold  more  firmly.  For  children 
and  difficult  patients  an  anaesthetic  may  be  given 
for  the  operation  of  fixing  the  splint,  especially 
if  there  is  any  difficulty  in  reducing  the  fracture. 
H.  J.  Kauffer  (8)  uses  a  cast  aluminium  splint 
in  wliich  "  the  saddle  is  discontmued  on  the 
labial  or  buccal  surface  for  a  space  of  several 
teeth  on  each  side  of  the  fracture."  He  fixes 
it  by  means  of  oxy-phosphate  of  copper  cement 
and  wiring  with  Angle's  ligature  wire.  "  Two 
pieces  of  wire  from  six  to  eight  inches  long  are 


of  the  mouth  and  curve  backwards  and  upwards, 
a  little  distance  from  the  skin  of  the  face,  and 


Fig.  925. — Kingsley  Splint. 

(KiNGSLEY  : 

twisted  together  about  three  inches  from  one 
end ;  the  long  ends  are  then  passed  on  each  side 
of  a  tooth  from  the  lingual  to  the  buccal  side 
close  to  the  gingival  margin,  and  the  wire  is 
twisted  until  the  tooth  is  held  firmly  in  the 
wire  loop.  The  ends  of  the  wire  are  brought 
from  each  side  up  over  the  top  of  the  splint, 
twisted  together,  and  cut  off  just  short  enough 
to  permit  the  ends  to  be  turned  under  the  spUnt 
and  out  of  the  way.  Li  this  mamier  the  splint 
is  secured  to  the  teeth  in  much  the  same  way 
as  one  often  sees  a  cork  tied  into  a  bottle. 
Several  teeth  should  be  used,  and  it  is  well  to 
twist  the  wire  from  the  lingual  side  of  one  tooth 
to  the  wire  from  the  buccal  side  of  another." 

The  Hayward  or  Kingsley  (9)  splint  (see  Fig. 
925)  differs  only  from  those  described  in  one  chief 
particular.  It  is  made  of  metal  or  vulcanite 
loos°ly  fitting,  and  two  ^vires  about  an  eighth  of 
an  inch  thick  are  soldered  to  the  metal  or  inserted 
■in  the  vulcanite,  and  pass  outwards  at  the  angles 


Oral  Deformities.) 


Fig.  926. — Kingsley  Splint  in  position. 

(Kingsley  :  Oral  Deformities.) 

terminate  opposite  the  condyles.  On  each 
wire  two  spurs  or  points  directed  upwards  and 
outwards  are  soldered,  one  near 
the  back  end  and  one  about  an 
inch  behind  the  angle  of  the 
mouth.  If  the  splint  is  made 
of  vulcanite,  the  upper  surface 
can  be  so  modelled  and  hollowed 
out  as  to  fit  the  crowns  of  the 
upper  teeth  and  thereby  greatly 
aid  mastication.  When  the 
splint,  lined  with  gutta-percha, 
is  in  position,  a  bandage  is 
appUed  passing  round  the  wires 
and  under  the  chin,  and  it  is 
well  to  have  either  a  lined  gutta- 
percha chin-cap  or  a  soft  pad  intervening  between 
the  bandage  and  the  chin  (see  Fig.  926).  The 
anterior  spurs  serve 
to  prevent  the  band- 
age slipping,  and  the 
posterior  ones  may 
be  used  to  fix  the 
bandage  there  when 
it  is  desired  to  pro- 
duce upward  pres- 
sure at  the  angle  of 
the  jaw. 

Tlie  Gunning  sphnt 
consists  of  a  viil- 
canite  cap,  lined  or 

unlined   with    gutta-      Fig.  927. — Gunning  Splint. 
percha,  covering  the    (Heatu:  Injuries  and  Diseases 

teeth  and  part  of  the  "/  the  Jaws.) 

alveolus     (see     Fig. 

927).     It  differs  from  the  Kingsley  in  having 
the  upper  surface  loosely  fitted  to  the  upper  teeth. 


696 


This  hollowed  surface  is  filled  with  gutta-percha,  I 
so  that  when  the  splint  is  applied  the  upper 
teeth  are  embedded  in  the  gutta-percha.  The 
jaw  is  fixed  with  a  four-tail  bandage.  The 
splint  is  perforated  in  many  places  to  allow 
escape  of  discharge,  and  for  syringing,  and  has 
a  large  slot-like  aperture  in  the  front  to  allow 
of  introduction  of  liquid  food. 

The  Hern  splint  is  a  modification  of  the 
Gunning  and  an  improvement  on  it.  The  upper 
surface,  instead  of  fitting  the  upper  teeth  all 
round,  has  in  a  few  places  short  raised  pillars 
of  vidcanite  hollowed  out  and  filled  with  gutta- 
percha. Into  these  hollows  certain  of  the  upper 
teeth  fit.  Tlie  jaw  is  fixed  with  skull-  and 
chin-cap  connected  at  the  sides  with  elastic 
webbing  and  buckles ;  and  it  is  wise  to  be  careful 
not  to  exercise  too  much  pressure,  as  this  is 
liable  to  promote  the  formation  of  abscesses 
in  the  inflamed  soft  parts  below  the  chin.  The 
chief  advantage  over  the  Gunning  splint  is 
that  the  upper  teeth  are  not  all  covered,  and 
that  space  is  left  free  between  the  splint  and 
the  upper  jaw,  so  that  cleansing  the  mouth  and 
feeding  the  patient  are  more  easily  carried  out. 
It  is  less  clumsy  and  more  comfortable  to  the 
patient,  and  more  easily  adjusted  and  removed. 

Except  in  the  case  of  horizontal  fracture  of 
part  of  the  alveolus,  when  a  simple  cap  is  often 
the  most  suitable  splint,  none  of  these  splints 
that  cover  the  teeth  should  be  used  unless  for 
one  reason  or  another  the  Hammond  splint  is 
inapplicable.  Wlien  a  selection  has  to  be  made 
between  them  the  simplest  form  that  will  serve 
the  purpose  should  be  chosen.  The  simple  cap, 
cemented  or  fixed  with  gutta-percha,  is  the  best 
when  the  displacement  is  easily  corrected  and 
not  much  force  is  necessary  to  retain  the  frag- 
ments in  position,  and  is  generally  most  useful 
when  the  fracture  is  at  or  near  the  symphysis. 
But  where  some  counter-support  is  necessary 
the  Kingsley  is  to  be  preferred  to  the  Gunning 
or  Hern,  because  the  jaw  is  not  fixed,  and  there- 
fore speech,  and  to  some  extent  mastication, 
are  possible,  and  the  mouth  can  be  kept  cleaner. 
It  cannot  be  used  successfully  in  edentulous, 
or  nearly  edentulous  mouths,  and  the  Hern 
splint  may  then  be  adopted.  The  disadvantage 
of  the  Kingsley  splint  is  that  the  patient  cannot 
lie  with  the  head  on  one  side  with  comfort,  and 
that  the  splint  is  apt  to  be  loosened  in  that 
way.  The  Gunning  splint  may  be  used  with 
advantage  where  both  jaws  are  fractured,  but 
otherwise  the  Hern  splint  is  to  be  preferred  to 
it.  Both  these  splints,  however,  are  to  be 
avoided  when  possible,  on  account  of  their 
liability  to  promote  sepsis,  and  the  discomfort 
to  the  patient,  on  account  of  the  dribbling  of 
saliva,  and  the  strain  on  the  mandibular  articu- 
lation occasioned  by  the  jaw  being  so  much 
gagged  open. 


The  methods  of  treating  a  fractured  mandible 
that  have  been  described  include  most  of  the 
splints  that  are  usually  employed  at  the  present 
day.  Rutenich  in  1799,  and  Lonsdale  and  others 
later,  used  a  kind  of  clamp  of  which  one  arm 
pressed  upon  the  crowns  of  the  teeth  and  the 
other  was  below  the  chin.  The  two  arms  were 
connected  in  such  a  way  that  pressure  could  be 
exerted  by  means  of  a  screw.  At  different 
times  various  splints,  which  were  modifications 
of  the  Kingsley  or  Gunning  splints,  or  were 
allied  to  them,  have  been  employed  by  vari- 
ous surgeons.  St.  George  Elliott  during  the 
American  Civil  War  used  largely  an  inter-dental 
splint  of  gutta-percha  designed  on  the  lines  of 
the  vulcanite  Gunning  splint.     An  inter-dental 


Fig.  928. — Carter's  Method  of  Wiring. 

(British  Dental  Journal.) 

splint  with  webbing  to  pass  under  the  chin, 
or  with  external  arms  and  screws,  is  described 
by  Moriarty  (11).  A  simple  way  of  obviating 
the  wires  of  the  Kingsley  sjDlint  is  shown  in 
Richardson's  Mechanical  Dentistry  (15).  The 
metal  frame  of  an  ordinary  fret-saw  is  used. 
To  the  upper  free  end  is  fixed  the  inter-dental 
vulcanite  splint,  to  the  lower  a  concave  chin- 
piece.  The  degree  of  approximation  is  con- 
trolled by  the  set-screw  and  rod. 

Wiring  the  teeth  adjacent  to  the  seat  of 
fracture  was  first  suggested  by  Hippocrates  in 
the  fifth  century  B.C.,  and  the  method  may  still 
be  uised  v^ery  occasionally  in  cases  of  horizontal 
fracture  of    part  of   the  alveolus,  and  in  cases 


697 


where  there  is  no  displacement,  or  at  any  rate 
no  tendency  for  the  displacement  to  recur  when 
it  has  been  corrected,  and  \\here  the  teeth  con- 
cerned are  perfectly  firm.  Otherwise  the  only 
result  is  generally  to  loosen  the  teeth  ligatured ; 
but  the  method  is  of  use  as  a  temporary  ex- 
pedient in  cases  of  multiple  fracture  to  get  the 
fragments  nearly  in  position  before  taking  an 
impression. 

Wiring  the  bones  was  practised  by  Buck  of 
New  York  in  1847  and  by  Hugh  Thomas  of 
Liverpool  in  1863.  The  latter  drilled  a  hole 
through  the  bone  on  each  side  of  the  fracture, 
passed  wire  througli,  and  wound  each  of  the 
free  ends  into  a  coil  on  the  buccal  aspect.  The 
method  fell  into  disuse  because  it  did  not  hold 
the  bones  firmly  for  a  sufficient  length  of  time, 
and  because  it  was  liable  to  induce  necrosis  of 
the  fractured  ends.  T.  S.  Carter  (4)  of  Leeds 
has,  however,  adopted  with  much  success  a 
modification  of  Thomas's  method.  He  uses 
an  electric  engine  and  drills  the  lioles  not  less 
than  a  quarter  of  an  inch  from  the  fractured 
ends  and  between  the  roots  of  the  teeth ;  he 
uses  silvered  copper  ^vire,  No.  19  gauge,  and 
twists  the  ends  together  on  the  buccal  side  by 
means  of  a  special  key  (Fig.  928).  It  would 
seem  that  the  surgical  treatment  of  fractured 
mandible   has   not   been   adequately   tried   by 


in  the  upper  and  lower  jaws.  The  bands  are  fixed 
to  the  teeth  by  means  of  cement  and  the  screw 
and  nut.  Attached  to  the  outer  surface  of  the 
bands  are  small  buttons,  and  a  wire  or  fibrous 
ligature  is  twisted  tightly  round  the  buttons 
in  the  form  of  a  figure  of  eight ,  so  as  to  hold  that 


Fig.  929. — Angle's  Fracture  Bands. 
(AuGliE  :  Malocclusion  of  the  Teeth  and  Fracture  of  the  Maxillae.) 


other  operators,  and  with  modern  antiseptic 
methods  it  is  likely  that  the  disadvantages 
attendant  upon  A^dring  in  former  days  might 
be  avoided.  In  that  case  it  certainly  has  many 
advantages  over  splints.  Successful  cases  are 
recorded  by  Marshall  (10). 

A  metliod  of  comparatively  recent  intro- 
duction is  that  of  E.  H.  Angle  (2),  and  it  has 
been  successfully  employed  in  the  United  States 
and  in  Europe  (see  Fig.  929).  Small  German 
silver  bands  with  a  very  small  screw  and  nut 
attached,  similar  to  those  used  in  orthodontics, 
are  fitted  carefuUy  to  individual  opposing  teeth 


Fig.  930. — Angle's  Fracture  Bands. 

(Angle  :  Malocclusion  oj  the  Teeth  and  Fracture 

of  the  Maxillae.) 

portion  of  the  mandible  in  which  the  banded 
tooth  is  implanted  firmly  to  the  maxilla.  Such 
a  pair  of  teeth  is  usually  banded  and  ligatured 
on  each  side  of  the  fracture  but  not  clo.se  to  it. 
By  this  means  the  displacement  is  corrected, 
and  the  whole  mandible  firmly  fixed.  In  some 
cases  it  may  be  necessary  so  to 
treat  more  than  one  pair  of  teeth 
,, ,,...  on  either  side   of  the   fracture. 

In  other  cases,  as,  for  instance, 
fracture  at  the  angle,  two  pairs 
of  bands  may  be  appUed  farther 
forward  on  the  same  side. 

As  a  modification  of  this  plan, 
in  some  cases  a  tooth  on  each 
side  of  the  fracture,  but  not  close 
to  it,  may  be  banded,  and  the 
bands  ligatured  together,  the 
ligature  passing  round  the  labial, 
or  both  the  labial  and  lingual, 
surfaces  of  the  intervening  teeth 
(see  Fig.  930).  Further  support 
may  be  gained  by  comiecting 
laliial  and  lingual  ligatures  by 
means  of  ligatures  passing  be- 
tween the  several  intervening  teeth,  so  that  the 
two  main  ligatures  are  firmly  connected  together. 
This  method  of  ligaturing  the  two  fragments  is 
really  a  greatly  improved  modification  of  the 
Hippocratic  method  of  wiring  the  teeth,  and 
where  it  will  suffice  is  to  be  preferred  to  the  plan 
of  ligaturing  the  mandible  to  the  maxilla,  because 
the  jaw  is  not  fixed.  Several  cases  in  which 
Angle  bands  were  used  have  been  recorded  bj' 
Marshall  (10). 

H.  J.  Kauffer  (8),  instead  of  using  Angle 
bands  attached  to  upper  and  lower  teeth, 
adopts    the    plan    of    inter- wiring — "  that    is, 


698 


binding  the  upper  and  lower  jaws  together  by 
passmg  the  wire  around  the  necks  of  enough 
teeth,  upper  and  lower,  and  interlacing." 

It  is  not  usually  necessary  or  convenient  to 
fix  a  splint  when  the  patient  is  first  seen,  unless 
it  can  be  completed  before  swelling  has  super- 
vened. It  is  usually  better  to  make  use  of  a 
bandage  or  other  temporary  expedient,  and 
wait  for  some  hours  or  even  a  few  days  untO 
the  inflammation  has  abated. 

Loose  teeth  should  not  as  a  rule  be  removed 
unless  they  are  very  loose  or  interfere  with  the 
correction  of  displacement,  as  they  usually 
tighten.  Fractured  teeth  with  the  pulp  exposed 
may  cause  severe  pain  ;  the  puljj  should  then 
be  removed  \\ith  a  nerve-extractor,  under  the 
influence  of  an  anaesthetic.  Antiseptic  treat- 
ment is  very  necessary  before  the  ai^plication 
of  a  splint  or  surgical  treatment  and  during 
the  early  stages  of  repair.  Wlien  the  jaw  is 
not  fixed,  the  patient  should  use  a  mouth-wash 
frequently.  When  he  cannot  do  this  for  him- 
self, frequent  syringing  is  necessary.  The  teeth 
and  splint  should  be  kej)t  as  clean  as  possible 
by  careful  bnasliing. 

There  should  be  but  little  disturbance  of 
occlusion  after  efficient  treatment  of  fractured 
horizontal  ramus.  In  some  cases,  howe\-er, 
a  perfect  result  is  impossible,  and  it  may  be 
necessary  to  modify  it  by  grinding  down 
certain  teeth,  or  even  by  extraction. 

Treatment  of  Fracture  at  other  Positions. — The 
best  method  for  fracture  at  the  angle  as  a  rule 
is  to  mould  a  gutta-percha  splint  about  the 
angle  of  the  jaw,  taking  care  that  part  of  it 
goes  well  round  the  angle  and  edge  of  the 
horizontal  ramus.  The  splint  should  be  kept 
in  place  and  the  jaw  supported  by  means  of  a 
bandage  that  presses  firmly  round  the  seat  of 
fracture  and  also  supports  the  chin.  As  swelling 
subsides  the  splint  will  proljably  need  re-adjust- 
ment. Otherwise,  the  method  of  Ajigle  may  be 
employed.  Fracture  of  the  ascending  ramus, 
condyle,  or  coronoid  process  should  generally 
be  treated  with  a  bandage. 

2.— MAXILLA 

Causes. — Fracture  of  the  maxilla  is  much  less 
common  than  fracture  of  the  mandible.  It  is 
always  caused  by  direct  violence  of  a  severe 
character,  such  as  kicks,  falls  from  a  height, 
the  wheel  of  a  vehicle,  or  gunshot  injuries. 
The  extraction  of  a  tooth,  especially  if  im- 
properly performed,  may  cause  fracture  of  a 
considerable  portion  of  the  alveolus,  and  this 
is  most  liable  to  occur  in  the  case  of  the  third 
molar,  when  the  tuberosity  may  easily  be 
separated.  A  case  is  recorded  by  Ackery  and 
Paterson  (1)  in  which  the  entire  alveolar  portion 
was  separated. 


The  position  of  the  fracture  and  the  character 
and  degree  of  the  displacement  depend  upon  the 
nature  of  the  force  causing  the  fracture.  The 
displacement  is  sometimes  considerable. 

Varieties. — The  fracture  is  usually  compound 
to  the  mouth,  and  the  bone  is  frequently  com- 
minuted in  severe  cases. 

The  signs  and  symptoms  of  fracture  are  gener- 
ally quite  obvious,  but  where  there  is  no  clear 
displacement  an  umiatural  mobility  may  be 
noticed  and  crepitus  may  be  obtained. 

Complications. — These  are  in  general  similar 
to  those  occurring  in  connection  with  fracture 
of  the  mandible,  but  there  are  certain  complica- 
tions pecuhar  to  the  bone.  Haemorrhage  is  often 
more  severe  by  reason  of  the  extreme  degree  of 
vascularity  of  the  bone,  and  secondary  haemor- 
rhage is  not  uncommon.  Injury  to  the  infra- 
orbital nerve  has  sometimes  occurred.  The 
maxillary  sinus  or  nasal  cavities  may  be 
opened  up,  and  the  fracture  may  extend  to 
the  sphenoid  bone  and  open  up  the  cranium. 
Other  bones  of  the  face,  such  as  the  malar, 
ethmoid  and  nasal  bones  may  of  course  be 
fractured  at  the  same  time.  Necrosis  is  less 
likely  to  occur  than  in  the  case  of  the 
mandible  on  account  of  the  high  degree  of 
vascularity. 

Prognosis. — Except  in  the  case  of  severe 
injury  the  expectation  of  recovery  and  reunion 
of  bone  is  good.  Even  comminuted  fractures 
usually  unite  quite  well  and  splinters  of  bone 
should  not  be  removed. 

Treatment. — When  the  displacement  has  been 
corrected  there  is  not  generally  much  tendency 
for  it  to  recur,  and  a  bandage  is  the  only  treat- 
ment required.  Where  there  is  any  difficulty 
in  retaining  the  fractured  portion  in  position  it 
is  permissible  to  wire  the  teeth.  Otherwise  some 
form  of  splint  should  be  used,  and  the  best  for 
tlie  purpose  is  a  simple  cap  cemented  or  fi.xed 
\\  ith  gutta-f)ercha,  or  the  Hammond  or  Gunning 
splint  j)reviously  described.  The  Gunning  splint 
should  generally  be  used  when  both  jaws  are 
fractured.  The  methods  of  Angle  are  also  apj)li- 
cable  to  the  maxilla ;  when  the  jaws  are  con- 
nected together  the  mandible  is  then  really 
used  as  a  splint  to  hold  the  fractured  maxilla 
in  position. 

An.  interesting  case  is  recorded  by  F.  J. 
Padgett  (13)  in  «liich  a  horizontal  fracture, 
together  with  vertical  fractures  on  each  side 
in  the  neighbourhood  of  the  premolars,  occurred. 
It  was  successfully  treated  by  means  of  a 
modified  Hayward  splint  closely  fitting  the 
teeth  and  bridging  over  gaps ;  pressure  was 
obtained  by  using  a  skuU-cap. 

The  remarks  made  about  loose  and  fractured 
teeth  in  the  mandible  apply  equally  to  the 
maxilla,  and  antiseptic  treatment  should  be 
conducted  on  similar  lines. 


699 


DISLOCATION  OF  THE  MANDIBLE 

Dislocation  of  the  mandibular  articulation 
may  occur  on  one  side  or  both,  the  latter  being 
more  common  in  the  proportion  of  about  three 
to  two,  according  to  Roughton  (16). 

Causes. — It  is  usually  caused  by  direct 
violence,  but  may  occur  as  the  result  of  sudden 
and  excessive  mu.scular  action.  Direct  violence 
may  be  external  or  internal  :  the  same  kind  of 
force  that  may  produce  fracture  \\hen  the 
mouth  is  shut  is  liable  to  cause  dislocation  when 
it  is  open ;  forcing  large  objects  into  the  mouth, 
as  for  instance  in  taking  an  impression,  may 
produce  dislocation,  or  it  may  occur  from 
downward  pressure,  without  support  of  the 
mandible,  in  extracting  a  lower  tooth.  Ex- 
amples of  muscular  action  are  violent  yawaiing, 
vomiting  or  sneezing.  Whatever  the  direct 
cause,  in  any  case  it  is  probable  that  spasmodic 
contraction  of  the  external  pterygoids  completes 
and  fixes  the  dislocation. 

Pathology. — The  inter-articular  fibro-cartilage 
remains  attached  to  the  condyle,  which  passes 
in  front  of  the  eminentia  articularis.  The 
capsular  ligament  is  not  usually  torn,  but  all 
the  ligaments — external  lateral,  internal  lateral 
and  stylo-mandibular — are  stretched.  The 
coronoid  process  almost  if  not  quite  touches 
the  base  of  the  malar  process,  but  does  not  pass 
in  front  of  it.  The  temporal  muscle  remains 
attached  to  the  coronoid  process  and  forms  a 
fulness  palpable  beneath  the  zygoma. 

Complications  do  not  occur  as  a  rule,  but 
Bowden  (3)  records  a  case  of  deafness  following 
dislocation  happening  during  tooth-extraction  ; 
it  ^^•as  doubtful  whether  the  deafness  was  the 
direct  result  of  injury  or  not. 

Signs  and  Symptoms. — In  bilateral  dislocation 
the  mouth  is,  of  course,  widely  open  and  the 
mandible  protruded.  The  condyles  and  coronoid 
processes  can  be  felt  in  their  misplaced  positions. 
The  masseter  is  stretched  and  tonically  con- 
tracted. In  the  case  of  unilateral  dislocation 
the  jjrotrusion  and  extent  of  opening  are  not 
so  marked,  and  of  course  the  displacement  can 
only  be  felt  on  one  side.  The  mandible  deviates 
towards  the  normal  side,  differing  in  this  respect 
from  what  occurs  with  fracture  of  the  neck 
of  the  condyle. 

Reduction  is  usually  effected  fairly  easily. 
The  patient  should  be  placed  in  a  low  chair 
with  the  head  supported.  The  jaw  should  be 
grasjied  with  both  hands,  the  thumljs  being 
placed  on  the  crowns  of  the  molars,  and  the 
fingers  beneath  the  horizontal  ramus  as  far 
forward  as  possible  (see  Fig.  931).  Firm  down- 
ward and  backward  pressure  should  be  made 
with  the  thumb  and  upward  pressure  with  the 
fuigers,  so  as  to  force  the  condyle  past  the 
eminentia,    when    it    will    at    once    sliii    into 


the  mandil)ular  fossa.  The  thumbs  should  be 
protected  with  napkins. 

Another  method  is  to  place  a  cork  between 
the  upper  and  lower  molars  on  each  side  and 
force  the  chin  upwards,  but  it  does  not  so  well 
carry  out  the  principle  of  reversing  the  path 
by  which  dislocation  occurred.  Li  case  of 
difficulty  ether  should  be  given  to  relax  the 
muscles.  After  reduction,  the  mandible  should 
be  supported  and  fixed  with  a  four-tail  bandage. 

Unreduced  Dislocations  acquire  after  some  time 
a  certain  degree  of  freedom  of  movement,  but 
even  after  several  months  an  attempt  should 
be  made  to  reduce  the  dislocation,  failing  which 
surgical  treatment  may  be  necessary. 


Fig.  931. 


-Metliod  of  Reduction  in  Dislocation  of 
Mandible. 


With  some  persons  dislocation  occurs  very 
easily  and  may  happen  frequently;  reduction 
is  often  effected  by  the  patient.  An  elastic 
support  may  l:)e  worn,  or  surgical  treatment 
may  be  adopted  to  control  the  movements  of 
the  condyle. 

A  condition  formerly  regarded  as  partial 
dislocation  is  called  subluxation.  It  was  sup- 
posed to  occur  in  patients  with  lax  tissues  of 
the  joint,  but  the  clicking  noise  frequently 
heard  is  indicative  of  some  form  of  chronic 
arthritis,  wliich  is  probably  the  real  cause  of 
the  condition.  N.  G.  B. 

BIBLIOGRAPHY 

(1)  ACKBRY,  J.,  and  Paterson,  W.  B.  A  Case  of 
Fracture  of  the  Maxilla.  Trans.  Odont.  Soc, 
1889^90,  Vol.  XXII,  p.  65. 


700 


(2)  Angle,    E.    H.     Malocclusion   of   the    Teeth   and       (10) 

Fracture  of  the  Maxillae. 

(3)  BowDEN,    G.    H.     Case    of     Deafness     following 

Bilateral  Dislocation  after  Extraction  of  Molars.        (11) 
Trans.  Odont.  Soc,  1896-7,  Vol.  XXIX,  p.  90. 

(4)  Carter,  T.  S.     Treatment  of  Fractures  of  Mandi-       (12) 

ble.     Brit.  Dent.  Jour.,  1900,  Vol.  XXI,  p.  311. 

(5)  CoLYER,   J.    F.     Dental   Surgery   and   Pathology,       (13) 

pp.  836-858. 

(6)  Gould,    Sir   A.   Pearce.     Fracture   of  Neck  of       (14) 

Mandible.       Trans.    Odont.    Soc,    1890-1,    Vol. 
XXIV,  p.  184.  (15) 

(7)  Heath,  C.     Injuries  and  Diseases  of  Jaws.     4th        (16) 

ed.  pp.  1-88. 

(8)  K.iUFFER.  H.  J.     Demonstration  of  Methods  in 

the  Treatment  of  Simple  and  Complicated  Frac-       (17) 

tures  of  the  Jaw.    X»en(aZ  Cosmos,  1913,  Vol.  LV, 

pp.  249-62.  (18) 

(9)  KiNGSLEY,     Norman.     Oral     Deformities,     1888, 

pp.  361-411. 


Marshall,    J.    S.     Treatment    of    Fractures    of 

Mandible.     Dental  Cosinos,  1905,  Vol.  XLVII, 

pp.  431-8. 
Moriarty,    p.    W.     Fractures    of    Jaw.     Dental 

Cosmos,  1906,  Vol.XLVIII,  pp.  1195-9. 
Newl.a.nd-Pedley,  F.     Trans.  Odont.  Soc,  1884- 

5,  Vol.  XVII,  p.  16. 
Padgett,  F.  J.     Unusual  Fractures  of  Maxilla. 

Brit.  Dent.  Jour.,  1907,  Vol.  XXVIII,  p.  1209. 
Payne,  J.  Lewin.     Proc.  Roy.  Soc.  of  Med.  (Odont. 

Sec),  Vol.  II,  p.  161. 
K1CHARD.SON.     Mechanical  Dentistry. 
Roughton,  E.  W.     0)al    Surgery.     Fractures  of 

Mandible    and    Maxilla,   p.    1 ;    Dislocations   of 

Mandible,  p.  15. 
Whittles,   J.    D.     Cases   of   Fracture   of  Jaws. 

Trans.  Odont.  Soc,  1902-3,  Vol.  XXXV,  p.  44. 
Williams,   H.   Lloyd.     Fractiu'es   of   Mandible. 

Trans.    Odont.    Soc,    1898-9,   Vol.   XXXI,   p. 

59. 


CHAPTER  XLVI 


ORAL   SEPSIS 


In  the  term  Oral  Sepsis  are  included  all 
common  chronic  inflammatory  conditions  about 
the  mouth.  It  thus  comprises  all  forms  of 
gingivitis ;  of  chronic  infective  periodontitis 
(pyorrhoea  alveolaris) ;  of  septic  diseases  of 
the  tooth-pulp,  whether  simple  inflammatory, 
suppurative,  or  gangrenous;  and  of  dental 
caries,  chiefly  the  later  stages  after  destruction 
of  the  crown  of  the  tooth,  when  a  septic  partially 
necrotic  root  is  left  in  the  alveolar  process.  It 
is  thus  clear  that  oral  sepsis  is  not  a  specific 
disease,  but  merely  a  convenient  term  for 
including  all  chronic  forms  of  sepsis  about  the 
mouth. 

With  the  onset  of  this  condition  there  are 
added  to  the  normal  contents  of  the  mouth — 
the  oral  secretions,  leucocjrtes  and  cast-off 
epitlieUum — tlie  abnormal  products  of  tissue- 
reaction  to  injury,  that  is,  inflammatory  exu- 
dation, which  is  rich  in  proteid,  and  an 
enormous  increase  of  dead  cells,  epithelial  and 
others.  The  environment  of  the  oral  flora  is 
thus  changed,  and,  as  a  consequence,  an  altera- 
tion takes  place  in  the  flora  itself.  There  is 
good  reason  to  believe  that  the  alteration 
consists  not  only  in  an  actual  increase  in  the 
number  and  variety  of  the  organisms,  but 
in  a  change  in  the  virulence,  either  in  the 
direction  of  attenuation  or  exaltation,  of  those 
recently  introduced  and  of  those  in  previous 
occupation.  The  host  is  thus  threatened  with 
new  dangers  due  to  recently  introduced  organ- 
isms— the  possible  rise  in  vii'ulence  in  some 
cases  of  varieties  previously  non-pathogenic 
or  only  slightly  so,  and  an  increased  oppor- 
tunity for  associatied  bacterial  action  (sym- 
biosis). A  proportion  of  the  inflammatory 
products  stagnates  in  the  mouth,  chiefly  around 
the  teeth,  and  in  it  the  organisms  grow  and 
produce  their  toxins,  ^^■hich  act  directly  upon 
the  subjacent  tissues  and  further  injure  them. 
As  the  condition  progresses,  the  organisms 
hitherto  confined  to  the  surface  of  the  tissues 
invade  them,  and,  following  the  general  rule 
in  such  cases,  increase  in  virulence  towards 
the  host,  and  may  also  pave  the  way  for  invasion 
by  other  organisms.  In  addition  to  the  local 
infection  that  is  thus  brought  about,  there  is 
the  still  more  important  infection  of  the  gastro- 
intestinal tract,  due  to  the  constant  swallowing 
of  purulent  and  bacteria-laden  sahv^a. 


Against  this  widespread  attack  the  body 
possesses  certain  means  of  defence,  which  may 
be  divided  into  local  and  constitutional,  or 
better,  into  primary  and  secondary. 

Of  the  primary  there  are — 

(1)  The  positive  chemiotactile  action  of  the 

saliva,  induced  by  the  action  of 
microbial  ferments  upon  the  salivary 
leucocytes.  These,  by  their  phagocy- 
tic action,  account  for  the  death  of 
numerous  bacteria. 

(2)  The  antiseptic  action  of  the  gastric  juice, 

due  to  the  presence  in  it  of  hydrochloric 
acid.  This  property  luifortunately  is 
present  only  towards  the  height  of 
normal  digestion  and  is  then  inter- 
mittent ;  Macfadyean  has  shown  that 
only  a  certain  proportion  of  bacteria 
entering  the  stomach  are  therein 
destroyed. 

(3)  The  struggle  for  existence,  about  which 

very  little  is  known,  among  micro- 
organisms in  the  small  and  large 
intestines. 

The  secondary  or  constitutional  defences  of 
the  body  are  those  brought  about  by  the  reaction 
of  the  tissues  to  the  action  of  bacteria  and  their 
products.  They  constitute  what  is  known  as 
the  resistance  of  the  body,  and  differ  in  degree 
in  each  individual  case. 

The  pollution  of  the  gastro-intestinal  canal 
leads  to  certain  important  results,  which  it  is 
necessary  to  mention. 

(1)  It  has  been  shown  that  during  digestion 
in  normal  dogs  the  intestine  allows  the 
passage  of  organisms  through  its  walls. 
These  are  found  in  the  liver,  spleen, 
and  other  organs,  and  they  disappear 
with  the  completion  of  digestion.  Thus 
they  do  not  appear  to  be  able  to  multi- 
ply in  the  body,  and  camiot  therefore 
be  considered  to  infect  it.  It  is  safe  to 
assume  that  similar  conditions  obtain 
in  normal  human  beings.  With  the 
poUution  of  the  intestine;,  due  to  oral 
sepsis,  it  is  probable  that  the  new 
varieties  of  organisms,  and  the  old 
varieties  in  an  altered  state  of  virulence, 
wfll  be  admitted  into  the  body,  which, 


701 


702 


in  order  to  meet  therii,  will  be  com- 
pelled to  increase  and  vary  its  means 
of  defence.  It  is  not  surprising  that 
the  wonderful  capacity  for  meeting 
such  attacks  that  the  body  possesses 
does,  in  many  cases,  ultimately  break 
down,  and  that  new  diseases,  which 
are,  strictly  speaking,  sequelae  to  the  i 
diseased  state  in  the  mouth,  are  brought 
about. 

(2)  The  new   flora   may  act  locally   on  the 

intestinal  walls,  producing  a  catarrhal 
condition  and  an  alteration  in  the 
normal  secretions,  and  so  lead  to  a 
disordered  digestion. 

(3)  The  products  of  digestion,  and  of  putre- 

faction (which  normally  takes  place  in 
the  intestine),  may  themselves  be  acted 
upon  by  the  organisms,  and  so  lead 
to  umaatural  results. 

The  above  is  but  a  brief  account  of  what  may 
be  called  the  principles  that  underlie  the  argu- 
ment in  favour  of  oral  sepsis  as  an  important 
aetiological  factor.  To  fail  to  realize  this 
importance  is,  as  William  Ewart  has  said,  "  to 
neglect  the  method  of  pathological  inference 
that  has  hitherto  been  followed  with  so  much 
success  in  the  aetiological  study  of  disease." 

It  is  now  necessary  to  turn  to  a  more  detailed 
study  of  certain  of  the  secondary  infections, 
etc.,  that  have  been  attributed  to  oral  sepsis. 
For  the  sake  of  description  the  following  scheme, 
for  which  no  scientific  accuracy  is  claimed,  will 
be  made  use  of. 

DISEASES  ASSOCIATED  WITH  CHRONIC  SEPTIC 
PROCESSES    IN    THE    MOUTH 

A.  Local  infections. 

B.  Due  to  the  spread  of  infective  material 

along  natural  channels — oesophagus, 
auditory  tube,  the  parotid  duct,  etc. — 
into  the  tissues. 

C.  Due  to  the  continuous  passage  of  bacteria 

into  the  tissues,  or  to  the  absorption  of 
toxins,  or  abnormal  oro-gastro-intestinal 
products  (sapraemic  or  toxaemic  states). 

D.  Due  to  infection  by  bacteria  of  the  tis- 

sues at  some  point  or  points  in  the 
oro-gastro-intestinal  tract  (septicaemic 
states). 

E.  Diseases  influenced  by  oral  sepsis. 

A.  Local  Infections 

(1)  Diseases  of  the  upper  respiratory  tract. 

(2)  Lymphadenitis. 

(1)  Upper  RESPraATORY  Tract. — The  sepsis 
from  the  mouth  may  spread  backwards  and 
infect  the  tissue  with  which  it  comes  into  con- 
tact.    Thus  it  may  lodge  in  the  crypts  of  the 


tonsUs,  and  organisms  infecting  the  substance 
of  those  organs  may  lead  to  their  enlargement. 
Of  231  school  children  suffering  from  unilateral 
enlargement  of  the  tonsil,  Stewart  found  that 
135  had  dental  caries,  mostly  of  the  lower  molars, 
and  oral  sepsis  on  the  side  of  the  enlarged 
tonsil ;  that  67  had  dental  caries  and  oral 
sepsis  on  both  sides;  that  16  had  no  oral 
sepsis ;  and  that  15  had  dental  caries  and  oral 
sepsis  on  the  opposite  side.  The  same  writer 
records  cases  of  laryngitis  that  cleared  up  on 
the  treatment  of  the  associated  oral  sepsis  (62). 

In  chronic  pharyngitis  it  is  often  impossible 
to  find  any  source  of  infection  other  than  from 
the  mouth.  Hunter  states  that  it  is  always 
associated  with  septic  gastritis  due  to  oral 
infection  (40). 

Bellei  records  a  case  in  which  a  woman  who 
had  suffered  from  chronic  inflammation  for 
many  years  "  caught  a  cold  ",  which  was  accom- 
panied by  pyrexia,  and  subsequently  by  pharyn- 
gitis. The  matter  appeared  of  little  moment 
until  she  had  a  sudden  attack  of  pain  in  one 
ear.  She  then  developed  symptoms  of  mastoid 
suppuration,  which  on  diagnosis  was  at  once 
operated  upon.  Unfortunately,  a  general  strep- 
tococcal iiifection  followed  the  operation,  and 
the  patient  died  a  few  days  later  (5). 

(2)  Lymphadenitis. — With  certain  rare  ex- 
ceptions, enlargement  of  glands  is  always  due 
to  the  direct  or  indirect  influence  of  bacteria. 
This  rule  applies  to  glands  in  the  neck,  so  that 
the  causes  that  bring  about  their  enlargement 
will  be  found  to  be  bacterial  diseases  of  the 
tissues  that  they  drain.  In  normal  children 
who  have  suffered  no  previous  illness  the 
cervical  glands  are  practically  impalpable  ;  only 
a  very  slight  stimulus,  however,  is  needed  to 
produce  active  proliferation  of  the  adenoid 
tissue,  the  recession  of  which  may  take  months 
or  years,  and  is  probably  never  complete. 

The  causes  of  chronically  enlarged  glands  in 
the  neck  thus  fall  naturally  into  two  classes. 
In  the  first  are  placed  pre-existing  causes,  such 
as  acute  fevers,  stomatitis,  catarrhal  conditions 
of  the  oral  and  nasal  mucous  membranes,  etc. ; 
this  is  by  far  the  larger  class.  In  the  second 
are  the  exciting  causes,  namely,  septic  condi- 
tions of  the  associated  parts.  It  is  often  very 
difficult,  and  sometimes  impossible,  to  satisfy 
oneself  which  tissue  or  organ  is  the  source  of 
infection ;  but  not  infrequently,  although  a 
combination  such  as  chronic  stomatitis,  in- 
flamed or  dead  tooth-pulps,  tonsillitis  and 
adenoids  must  be  held  responsible,  it  is  often 
possible  to  determine  approximately  \^hich  is 
the  tissue  chiefly  at  fault.  It  is  this  difficulty, 
together  with  a  want  of  agreement  upon  funda- 
mental standards,  that  has  led  to  the  marked 
differences  that  appear  in  statistics  that  have 
been  published  upon  this  subject.     Compare, 


703 


for  example,  those  on  the  relationship  of  en- 
larged cervical  glands  to  dental  caries  published 
by  Odenthal  and  by  HojDpe.  The  former 
states  that  27' 8  per  cent  of  the  children  he 
examined  had  enlarged  glands  and  no  caries, 
and  42- 9  per  cent  had  enlarged  glands  with 
caries;  the  latter  found  these  relationships  to 
be  represented  by  52  and  68' 7  per  cent  (33). 
All  that  the  statistics  tell  us,  however,  is  this  : 
that  both  observers  are  agreed  that  most  cases 
of  eidarged  glands  are  accompanied  by  carious 
teeth — an  agreement  the  truth  of  which  is 
supported  by  Halle,  of  Berlin,  who  found  79 
per  cent  of  the  children  he  examined  had  en- 
larged glands  and  carious  teeth  in  the  lower  jaw. 
This  last  observer  also  noticed  that  in  70  per 
cent  of  the  cases  with  enlarged  glands  the 
corresponding  teeth  were  carious,  and  that  in 
half  of  the  teeth  the  pulps  were  still  living  (31). 

It  is  misleading  to  try  to  reduce  such  relation- 
ships to  figures,  and  reliance  should  be  placed 
rather  upon  clinical  observation,  more  especially 
with  regard  to  treatment.  Clinically,  enlarged 
cervical  glands  appear  in  a  large  proportion  of 
cases  to  be  due  to  pre-existing  conditions  ;  many 
are  due  to  infection  through  the  tonsil  and 
adenoids,  and  a  very  small  proportion  to  direct 
infection  through  the  tooth-pulp.  The  teeth 
that  give  rise  to  most  trouble  are  the  first  and 
second  molars  when  necrosis  of  the  pulp  occurs 
before  the  closure  of  the  ends  of  the  roots.  Oral 
sepsis  may,  and  probably  does  as  a  rule,  act 
indirectly  by  first  infecting  the  tonsils  and 
adenoids. 

Enlarged  cervical  glands  are  in  a  condition 
of  lessened  resistance  and  often  become  tuber- 
culous, and  for  this  reason  are  often  spoken  of 
as  being  in  a  'pre-tubercular  state.  There  are, 
probably,  three  important  paths  by  which  they 
may  be  infected  with  tubercle  bacilli,  namely, 
the  intestine,  the  tonsils,  and  the  teeth.  The 
intestine  is  at  the  present  moment  considered 
to  be  their  most  frequent  point  of  entrance  into 
the  body.  By  means  of  the  lymph  vessels  they 
are  conveyed  to  the  blood,  and  by  it  distributed 
over  the  whole  body,  in  which  they  may 
either  be  destroyed,  or,  finding  a  suitable  tissue 
of  lessened  resistance,  settle  and  multiply. 
Tubercle  bacilli  have  occasionally  been  demon- 
strated in  tonsillar  and  adenoid  tissue,  both  of 
which  probably  are,  at  times,  a  gate  of  entrance.  ' 
Although  infection  through  the  dental  pulp  is 
possible,  the  proofs  that  it  does  occur  rest  upon 
somewhat  insuificient  ground.  Two  critical 
cases  are  recorded  by  Starck  (61).  In  one,  a 
male  aged  18,  tubercle  bacOli  were  found  in 
covershp  preparations  made  from  carious  teeth  ; 
in  the  other,  a  female  aged  14,  the  bed  of  the 
first  left  lower  molar  consisted  of  characteristic 
tuberculous  tissue.  In  another  case,  a  patient 
of  S.  F.  Rose  had  a  large  abscess  in  the  jaw. 


The  suspected  tooth  was  extracted,  and  a  large 
"  abscess  sac  "  found  attached  to  the  root;  at 
the  same  time  some  glands  in  the  neck  were 
removed.  The  sac  was  proved  to  contain 
tuberculous  material,  and  the  glands  were 
similarly  affected  (13). 

It  is  not  always  possible  to  be  sure  whether 
cervical  glands  are  tuberculous  or  not.  Under 
such  circumstances,  if  an  obvious  source  of 
septic  infection  is  present,  it  should  be  treated, 
and  the  result  watched,  before  any  operative 
measures  on  the  gland  are  undertaken.  If 
this  rule  is  followed,  it  will  be  found  that 
many  glands,  some  possibly  slightly  tuberculous, 
will  resolve  in  a  truly  remarkable  fashion,  and 
the  patient  be  saved  the  hazard  and  the 
disfigurement  of  an  operation. 

B.  Secondary  Infections  due  to  the  Passage  of 
Infective  Material  along  Natural  Ducts 

(1)  Gastro-intestinal  affections. 

(2)  Secondary  parotitis. 

(3)  Secondary  pancreatitis. 

(4)  Septic  infections  of  the  bile-ducts. 

(1)  Gastko-intestinal  Affections 

(a)  Septic  Gastritis,  Enteritis,  and  Colitis. 
Many  years  before  the  importance  of  oral  sepsis 
was  recognized,  it  had  been  noticed  by  dental 
surgeons  that  the  removal  of  septic  teeth 
previous  to  the  fitting  of  a  denture  often  led 
to  an  immediate  improvement  in  the  general 
condition,  the  patient  in  most  cases  gaining  in 
weight.  It  was  correctly  inferred  by  them  that 
the  need  of  new  teeth  was  not  so  important  as 
the  need  for  the  removal  of  the  septic  ones.  It 
was  not,  however,  until  Hunter  published  an 
account  of  thirteen  cases  under  the  title  of 
"Septic  Gastritis"  that  the  attention  of  the 
profession  was  centred  upon  the  subject  (40). 
Few  physicians  now  doubt  that  this  relation  is 
a  real  one,  or  fail  to  appreciate  the  utter  use- 
lessness  of  treating  the  dyspepsia  by  means  of 
drugs  without  first  giving  their  attention  to  the 
septic  lesions  of  the  mouth.  It  is  no  ex- 
aggeration to  say  that  the  majority  of  cases  of 
dyspepsia  in  middle  life  owe  their  persistence 
to  oral  sepsis.  Many  patients,  especially  those 
under  forty,  have  a  remarkable  resistance  to 
oral  infection,  and  it  is  by  no  means  uncommon 
to  meet  with  cases  in  which  a  pyorrhoea  of 
many  years'  duration  is  unaccompanied  by 
any  apparent  gastric  or  constitutional  trouble. 
But  over  the  age  of  forty  the  cases  are  rare, 
the  resistance  of  patients  having  gradually 
broken  down.  It  is  possible  that  the  orgamsms 
themselves,  acting  upon  a  normal  mucosa,  may 
be  able  to  give  rise  to  a  septic  gastritis ;  but  it 
is  probable  that  many  of  these  cases  commence 
as  ordinary  simple  catarrh  of  the  stomach, 
brought    about    by    hurrying    over    food    or 


704 


insufficient  mastication  from  any  cause.  The 
sticky  exudation  forms  an  excellent  nidus 
whereon  the  organisms  from  the  mouth  can 
grow  and  directly  affect  the  gastric  walls. 
Whatever  may  be  the  pathology,  it  is  very 
certain  that  "  the  mucosa  of  the  stomach,  con- 
tinuously exposed  to  infection,  e.  g.  of  pus 
organisms  of  the  teeth,  becomes  eventually 
infected.  A  septic  catarrh  is  set  up,  never 
to  be  got  rid  of,  but  continuously  sustained 
by  the  influx  of  septic  organisms  into  the 
stomach  ;  if  continued  long  enough,  the  chronic 
catarrh  leads  to  the  usual  effects  of  a  glandular 
catarrh,  viz.  glandular  atrophy,  with  increase 
of  interstitial  tissue  around  "  (33). 

In  considering  the  prognosis  of  any  particular 
case,  it  is  necessary  to  ascertain  the  duration 
and  nature  of  the  gastric  symptoms  and  the 
age  of  the  patient.  It  may  generally  be  safely 
concluded  that  the  younger  the  patient  the 
better  is  the  prognosis,  and  that  old-standing 
cases  in  middle-aged  and  senile  patients  will 
only  improve  in  so  far  as  the  damaged  stomach 
is  capable  of  resolution  in  the  absence  of 
infection.  As  a  rule,  the  general  result  is  found 
to  be  improvement  in  all  cases ;  but  it  is  clear 
that  if  there  be  an  increase  of  interstitial  tissue 
the  glandular  elements  of  the  gastric  walls  must 
become  progressively  disabled. 

The  sepsis  from  the  stomach  escapes  through 
the  pyloric  opening  and  directly  infects  the 
bowel.  Thus  there  are  often  found  associated 
with  septic  gastritis  symptoms  of  intestinal 
troubles,  such  as  constipation,  diarrhoea,  and 
possibly  in  some  instances  mucous  colitis. 
Post-mortem  examinations  offer  ample  evidence 
of  concurrent  sepsis  of  the  whole  intestinal 
tract  (16). 

(6)  Gastric  Ulcer.  Bruce  Clarke  remarks 
that  "  the  cause  of  gastric  and  duodenal  ulcers 
is  wrapped  in  obscurity  "  (9).  He  believes  that 
oral  sepsis  is  responsible  for  many  gastric  ulcers, 
an  opinion  with  which  Robson,  Moynilian,  and 
Carless  concur  (8). 

Such  an  opinion,  even  though  expressed  by 
such  well-known  names,  cannot  be  unreservedly 
accepted.  There  is  no  doubt  that  the  gastric 
ulcers,  so-called,  of  young  females  may  occur 
in  f)atients  to  whose  mouth  no  exception  can 
be  taken ;  and  it  is  equally  sure  that  if  these 
patients  are  fed  with  slop  foods  for  long  periods, 
or  undergo  a  course  of  rectal  feeding,  oral  sepsis 
results  unless  scrupulous  care  is  taken  of  the 
mouth.  Patients  suffering  from  chronic 
duodenal  and  gastric  ulcers  generally  have 
unclean,  often  foul  mouths,  and  here  again  it  is 
very  difficult  to  decide  whether  the  oral  con- 
dition precedes  or  follows  the  gastric.  Whether 
or  not  sepsis  is  a  cause  in  either  class,  it  is  quite 
certain  that  if  present  it  exercises  a  marked 
influence  over  the  course  of  the  ulcers,  and  very 


little    improvement    takes    place    until    it    is 
treated. 

(2)  Secondary  Parotitis 

(3)  Secondary  Pancreatitis 

(4)  Septic  Infections  of  the  Bile-ducts 

It  was  shown  by  Bond  (7)  that  in  cases  of 
fistulae  in  man,  and  in  normal  ducts  in  animals, 
particles  of  pigment,  deposited  at  the  orifice 
of  the  ducts  or  in  the  ducts  themselves,  were 
carried  up  in  a  direction  contrary  to  the  flow 
of  the  normal  secretion.  He  came  to  the  con- 
clusion that  the  transference  of  these  particles 
was  due  to  an  upward  current  in  the  mucus 
that  normally  covers  the  epithelium  of  the  ducts. 
It  is  probable  that,  normally,  micro-organisms 
are  thus  carried  up  to  the  glands  and  washed 
down  again  during  active  secretion,  and  that 
no  infection  of  the  gland  appears  unless  certain 
abnormal  predisposing  causes  are  present. 
Bucknall  (7),  in  a  paper  deaUng  with  secondary 
parotitis,  states  that  one  or  other  of  the  following 
conditions  nuist  be  present — 

(a)  Increase  in  number  or  virulence  of  the 

organisms  at  the  mouth  of  the  duct. 

(b)  The  general  vitality  of  the  subject  must 

be  lowered. 
(r)  The  quantity  of  secretion  passing  down 

the  duct  and  normally  clearing  it  must 

be  diminished. 
(d)  A  changed  quality  of  the  saliva. 

To  the  last  condition  he  adds  lowered  bacteri- 
cidal quality  of  the  saliva,  which  must  be 
omitted  in  the  light  of  recent  research,  which 
has  proved  that  such  a  quality  does  not  exist. 
In  cases  of  oro-gastro-intestinal  sepsis,  the  first 
two  of  these  conditions  are  undoubtedly  present, 
the  third  is  ojjen  to  question,  and  the  fourth 
improbable. 

Slicroscopical  evidence  furnishes  further  proof 
of  the  ascending  nature  of  certain  infections  of 
the  parotid :  thus,  "  (o)  the  ducts  become 
blocked  with  debris  containing  micro-organ- 
isms ;  (b)  inflammation  first  begins  in  the  centre 
of  each  lobule  around  the  ducts,  and  at  a  point 
furthest  away  from  the  vessels ;  (c)  many 
lobules  are  simultaneously  affected.  Each 
becomes  centrally  necrosed,  and  then,  finally, 
by  extension  they  fuse  to  form  a  multilocular 
abscess  cavity  "  (7).  Bacteriological  evidence 
is  not  so  conclusive,  for  although  it  has  fre- 
quently been  shown  that  the  organisms  present 
in  the  duct  and  in  the  oral  cavity  are  identical, 
it  is  possible,  except  in  those  cases  where  the 
duct  is  completely  blocked,  that  the  mouth 
may  have  been  infected  from  the  duct. 

Secondary  infection  of  the  parotid  (and  of  the 
sub-maxillary  and  sub-lingual  glands)  is  un- 
common. It  occurs  in  cases  of  gastric  ulcer, 
of  typhoid  fever,  and  after  surgical  operations, 


705 


i.  e.  in  those  cases  in  «hich  the  patient  is  either 
not  fed  by  the  month  for  several  days,  or  fed 
only  npon  "slop  food",  and  in  which  oral 
cleanliness  has  not  been  carefully  attended  to. 
Maggs  (46)  reports  a  case  directly  traceable  to 
infection  from  an  abscessed  molar. 

Unfortunately  the  pancreas  and  Uver  are 
not  open  to  such  simple  clinical  observation 
as  the  salivary  glands ;  nevertheless  there  is 
considerable  evidence  to  show  that  they  are 
similarly  subject  to  an  ascending  infection. 
Thus  in  the  case  of  the  pancreas  "  the  micro- 
scopical examinations  show  that  the  inflamma- 
tion in  pancreatitis  probably  begins,  and  is 
most  marked,  around  the  ducts  in  the  centres 
of  the  lobules,  as  in  cases  of  parotitis  "  (7). 
The  rare  and  interesting  disease  of  the  liver 
known  as  hypertrophic  biliary  cirrhosis  (Hanot's 
disease),  in  which  each  individual  lobule  is 
surrounded  by  a  delicate  comiective  tissue,  is 
considered  by  many  to  be  secondary  to  an 
ascending  inflammation  of  the  bile-duct. 
Sepsis  is  also  supposed  to  play  an  important, 
perhaps  essential  part  in  the  production  of 
ordinary  portal  cirrliosis ;  but  in  this  case  the 
infection  probably  comes  through  the  portal 
circulation.  Both  these  diseases  would  probably 
repay  an  investigation  from  the  point  of  view 
of  primary  oral  infection. 

The  fatal  condition  known  as  suppurative 
cholangitis  is  almost  certainly  an  ascending 
infection,  due  in  many  cases  to  infection  from 
a  septic  duodenum,  itself  infected  from  a  septic 
mouth.  In  one  case  of  this  nature  the  patient, 
a  young  adult  male,  had  a  most  foul  mouth, 
his  gaU-bladder  was  choked  with  stones,  and 
his  liver  riddled  by  numerous  abscesses.  Mul- 
tiple gall-stones  of  mixed  composition  are 
believed  by  many  pathologists  to  depend  upon 
inflammation  of  the  gall-bladder,  and  are 
secondary  to  infection. 

C.  Conditions  due  to  the  Continuous  Passage  of 
Bacteria  into  the  Tissues,  or  to  the  Absorption 
of  Toxins,  or  Abnormal  Oro-gastro-intestinal 
Products  (Sapraemic  or  Toxaemic  States) 

(1)  Certain  forms  of  anaemia  and  debility. 

(2)  Cardiac  irregularity. 

(3)  Diseases  of  the  nervous  system. 

(4)  Rheumatism  and  infective  arthritis. 

(5)  Deformities  of  weakness. 

(1)  Certain  forms  of  Anaemia  and  Debility 

Pernicious  Anaemia. — Despite  the  extensive 
researches,  both  experimental  and  clinical,  of 
Hunter  during  the  last  twenty  years,  the 
aetiology  of  pernicious  anaemia  can  by  no  means 
be  said  to  be  established.  This  observer  gives 
to  oral  sepsis  the  all-important  position  of  chief 
predisposing  cause ;  only  this  view  will  be 
considered  here. 
23 


Hunter  (34)  liolds  that  oral  sepsis,  though  a 
potent  predisposing  cause,  is  unable  to  produce 
the  disease,  but  acts  by  inducing  an  uifliealthy 
condition  of  the  stomach  and  intestines  "  which 
favours  the  contraction  of  the  specific  (haemo- 
lytic)  infection  responsible  for  the  disease,  and 
which  favours  its  continuance  after  its  contrac- 
tion ".  This  view  is  consonant  with  his  belief 
that  "  the  essential  features  of  pernicious 
anaemia  are  an  excessive  destruction  of  the 
blood  corpuscles,  the  seat  of  the  disintegration 
being  the  portal  system,  more  especially  that 
contained  within  the  liver  and  the  spleen,  the 
process  seemmg  to  commence  by  a  liberation 
of  the  haemoglobin  in  the  spleen,  which  is 
carried  to  the  Sver  to  be  disposed  of." — Mott. 

Fascinating  as  these  views  held  by  Hunter 
and  his  disciples  undoubtedly  are,  many  argu- 
ments have  been  advanced  against  them.  The 
most  important  of  these  is,  in  view  of  the  fact 
that  oral  sepsis  is  so  exceedingly  common  :  Wliy 
is  pernicious  anaemia  not  more  common  ?  The 
answer  can  only  be  that  the  additional  infection 
required  to  bring  about  the  disease  must  itself 
be  very  rare — an  answer  that  does  not  appear 
strong  when  it  is  remembered  that  the  disease, 
though  rare,  is  ubiquitous.  Furthermore,  cases 
have  been  rej)orted  in  which  no  oral  sepsis  is 
said  to  exist,  a  fact  that  would  suggest  that  the 
oral  sepsis  in  some  cases  may  follow  the  disease. 
Despite  the  arguments,  both  aetiological  and 
pathological,  that  have  been  Ijrought  against 
Hunter's  view,  the  association  of  oral  sepsis 
and  pernicious  anaemia  is  extremely  common. 
The  doubts  that  most  certainly  exist  would  be 
speedily  put  to  rest  if  to  all  records  of  cases  were 
added  a  complete  account  of  the  oral  condition. 

"  Septic  Anaemia." — This  name  is  given  to  a 
form  of  anaemia,  which  in  its  intensest  form 
closely  resembles  pernicious,  but  ^^•hich  diff'ers 
in  its  pathology  (a  deficiency  of  blood  formation), 
in  the  character  of  the  blood  changes,  and  in  its 
prognosis.  There  is  little  question  that  it  is 
often  closely  associated  with  oral  sepsis,  and 
clears  up  after  treatment  of  the  mouth. 

Chlorosis. — The  form  of  anaemia  known  as 
chlorosis,  so  common  in  young  females,  does 
not  appear  to  be  in  any  way  due  to  oral  sepsis. 
On  the  other  hand,  the  two  conditions  often 
accompany  each  other,  and  when  such  occurs 
the  cure  of  the  anaemia  is  often  impossible 
without  the  cure  of  the  oral  sepsis  taking  place 
first.  In  one  case  recorded  by  J.  F.  Colyer 
(10)  the  patient  was  a  female  in  whom  anae- 
mia appeared  synchronously  with  sui^purative 
periodontitis.  Slie  remained  for  one  month 
untreated,  and  then  for  two  was  put  upon  a 
course  of  iron  and  various  tonics.  No  improve- 
ment of  the  mouth  or  the  anaemia  followed. 
The  periodontitis  was  then  dealt  with,  and  as 
the  discharge  of   pus   from  the  gums  lessened 


706 


the  anaemia  improved,  aud  the  patient  gradually 
recov'ered. 

Debility. — A  class  of  patient  exhibiting  symp- 
toms of  general  malnutrition,  sallow  complexion, 
lassitude,  loss  of  appetite,  and  intestinal  trouble 
is  generally  sjjoken  of  as  suffering  from  general 
debility.  The  condition  is  to  be  regarded  as 
toxaemic,  and  brought  about  by  absorjDtion 
from  the  alimentary  canal  of  bacterial  toxins 
and  other  abnormal  intestinal  products.  In 
many  cases  the  debUity  is  primarily  dejiendent 
upon  oral  sepsis.  The  results  of  treatment  of 
the  sepsis  are,  as  a  rule,  remarkably  satisfactory. 
In  children  suffering  from  oral  sepsis  and  show- 
ing signs  of  general  debility,  the  best  work  a 
dental  surgeon  can  do  for  them,  if  conservative 
treatment  is  impossiljle,  is  to  carry  on  a  relent- 
less war  against  their  septic  mouths.  "  Better 
no  teeth  tlian  septic  ones  "  is  a  good  maxim  to 
work  upon,  and  one  that  should  lie  borne  in 
mind  liy  those  who  have  the  care  of  children 
entru.sted  to  them.  The  fear  of  causing 
abnormality  in  the  positions  of  the  permanent 
teeth  by  such  a  wholesale  extraction  is  of 
secondary  importance,  in  face  of  the  fact  that 
it  is  necessary  to  tide  a  child  over  some  of  the 
most  critical  and  difficult  years  of  its  life,  when 
it  is  easy  to  undermine  permanently  its  future 
health.  J.  F.  Colyer  (12)  records  notes  of  six 
cases  of  children  who  were  suffering  from  oral 
sepsis  and  general  malnutrition.  In  five  of 
these  cases  the  children  were,  at  the  time  of 
commencing  treatment,  below  their  correct 
average  weight.  After  the  removal  of  their 
septic  teeth  there  was  a  rapid  gain  in  weight 
in  each.  In  the  sixth  no  increase  occurred  even 
after  three  months.  The  enlarged  tonsUs  and 
adenoids  from  which  this  child  was  suffering 
were  then  removed,  and  from  that  time  the 
patient  began  to  increase  in  weight.  The  last 
case  is  important,  as  it  shows  that  improvement 
in  general  health  and  weight  does  not  necessarily 
follow  removal  of  oral  sepsis  if  other  septic 
foci,  such  as  tonsils  and  adenoids,  are  also  found. 

(2)  Cardiac  Irregulakity 

Sir  Douglas  Powell,  in  the  Lumleian  lectures 
for  1899,  records  the  case  of  a  lady  who  suffered 
from  cardiac  irregularity  and  frequent  attacks 
of  spasmodic  heart  pains  unassociated  with 
valvular  disease.  Her  teeth  were  extensively 
carious,  and  her  gums  very  unhealthy.  She 
refused  to  have  her  teeth  treated,  but  she  went 
through  a  course  of  Nauheim  baths  and  resist- 
ance exercises,  and  her  digestion  was  attended 
to,  with  only  slight  relief.  After  tliis  she  con- 
sented to  have  her  mouth  treated,  and  from 
that  time  her  cardiac  symptoms  ceased.  Powell 
remarks  that  in  the  absence  of  dyspeptic  signs 
"  the  cardiac  symptoms  seem  to  be  due  chiefly 
to  reflected  irritation  from  the  teeth ".     It  is 


possible  that  this  conclusion  is  correct,  but  the 
irregularity  can  be  explained  on  the  assumption 
of  the  absorption,  either  from  the  mouth  or  the 
gastro-intestinal  tract,  of  a  toxin  having  a 
specific  affinity  for  certain  of  the  cardiac  nerves. 
Many  cases  of  irregular  action  of  the  heart 
will  be  found  to  be  associated  with  gastric 
dilatation,  due  primarily  to  oral  sepsis,  and  will 
resist  treatment,  as  in  the  above  case,  until  the 
teeth  and  gums  are  treated. 

(3)  Diseases  of  the  Nervous  System 

Under  the  term  "  Toxic  Neuritis  "  Hunter 
and  Goadby  have  pubUshed  certain  cases  that 
appear  to  owe  their  origin  to  oral  sepsis. 
In  one  of  Hunter's  cases,  a  male  aged  33, 
the  illness  began  with  diarrhoea,  pains  in  the 
stomach,  and  vomiting,  and  these  symptoms 
lasted  three  weeks.  A  month  later  he  had 
weakness  of  the  hands  and  arms  accompanied 
by  a  sensation  of  "  pins  and  needles  ".  During 
this  time  he  suffered  from  acute  jmins  in  the 
stomach,  and  was  very  depressed  and  anaemic. 
Two-and-a-half  months  after  the  onset  of  his 
niness  he  showed,  when  examined,  marked 
weakness  and  atrophy  of  all  the  muscles  of 
both  arms,  including  the  deltoids.  His  mouth 
presented  a  most  intense  condition  of  oral 
sepsis,  which  the  patient  admitted  had  been 
jDresent  for  twelve  years.  He  improved  rapidly 
after  treatment  of  the  oral  sepsis. 

The  disease  known  as  subacute  combined 
degeneration  of  the  spinal  medulla,  commonly 
associated  with  more  or  less  profound  anaemia,  is 
held  at  the  present  day  to  be  due  to  some  toxin. 
In  many  cases  it  is  thought  (by  Batten  (4)  and 
others)  that  the  toxin  has  its  origin  in  chronic 
infections  of  the  mouth  and  gastro-intestinal 
system. 

To  the  numerous  causes  that  are  held  re- 
sponsible for  neurasthenia,  oral  sepsis  has 
recently  been  added.  The  late  T.  D.  Savill 
gave  it  as  his  opinion  that  many  serious  nerve 
symptoms  of  the  class  called  functional  might 
be  produced  by  this  condition.  A  woman, 
aged  32  years,  who  consulted  him,  showed 
all  the  symptoms  of  aggravated  hysteria,  on 
which  the  usual  remedies  had  no  effect  until 
some  roots  concealed  beneath  her  artificial 
plate  had  been  removed,  Avhen  she  rapidly 
recovered.  He  beUeved  that  in  a  large  pro- 
portion of  his  out-patients  the  cause  of  their 
trouble  could  be  traced  to  pyorrhoea  alveolaris  ; 
and  among  the  symptoms  they  presented 
were  listlessness,  restlessness,  and  a  sense  of 
fatigue,  headache,  shivering  attacks,  nervous- 
ness, irritability,  and  so  forth. 

(4)  Rheumatism  and  Infective  Arthritis 

Payne  and  Poynton  have  sho\vn  that  rheu- 
matic fever  is  an  acute  specific  fever  caused  by 


707 


a  definite  micrococcus.  The  tonsil,  in  some 
cases,  has  been  found  infected  by  this  organism, 
which  is  supposed  to  gain  entrance  into  the  body,  [ 
in  some  cases  at  least,  through  this  organ.  It 
has  not  yet  been  settled  whetlier  oral  sepsis  i 
may  play  any  part  in  the  infection,  though  it 
would  seem  on  general  grounds  probable  that 
it  does  so. 

Under  tlie  term  "  Arthritis  Deformans  "  three 
comparatively  distinct  diseases  may  be  classed, 
namely,  osteo-arthritis  (hypertrophic  arthritis), 
rheumatoid  arthritis,  and  infective  arthritis. 
The  first  appears  to  be  quite  distinct  in  its 
aetiology,  course,  morbid  anatomy,  and  progno- 
sis from  the  other  two.  Infective  conditions 
do  not  play  an  important  part  in  its  genesis ; 
its  origin  is  insidious,  and  its  course  is  slow  and 
progressive.  It  attacks  generally  single  large 
joints,  and  occasionally  the  terminal  phalangeal  I 
joints,  producing  around  them  the  characteristic  ! 
Heberden's  nodules.  Of  the  two  other  diseases 
it  is  probable  that  rheumatoid  arthritis,  though 
often  indistinguishable  clinically  from  infective 
arthritis,  is  a  definite  disease  depending  either 
upon  infection  (Garrod),  or  upon  "  irritative 
and  productive  lesions  located  in  the  spinal 
cord,  and  especially  in  the  cervical  and  lumbar 
enlargements  "  (P.  W.  Latham).  As  such  wide 
differences  of  opinion  as  to  its  aetiology  exist, 
it  will  not  be  dealt  with  further  in  this  chapter. 

In  infective  arthritis  (non-suppurative)  the 
joints  affected  are  generally  the  larger,  some- 
times the  smaller,  joints  of  the  hand  (not,  as  a 
rule,  the  terminal).  The  swelling  around  the 
joint  is  fusiform  in  shape  ;  the  skin  is  reddened, 
and  the  glands  in  the  neighbourhood  are 
generally  enlarged.  In  endeavouring  to  locate 
the  source  of  the  infection  it  is  necessary  first 
of  all  to  exclude  gout,  syiDhilis,  and  acute 
gonorrhoeal  rheumatism.  The  commonest  points 
of  infection  are  from  the  mouth,  the  vagina, 
and  the  male  urethra ;  less  common  are  oral 
sepsis,  or  any  other  form  of  sepsis,  such  as 
bronchiectasis.  More  than  one  source  of  in- 
fection may  be  present ;  thus,  vaginal  and  oral 
sepsis  may  exist  together  in  the  same  patient. 
In  such  cases  it  will  be  found  that  the  treatment 
of  one  source  will,  as  a  rule,  lead  to  some  improve- 
ment in  the  patient's  condition,  which  wUl 
remain  stationary,  or  again  recede,  unless  the 
other  sources  are  dealt  ^^ith  also.  A  case  shown 
by  Percy  Kidd,  at  the  Clinical  Society  in  October 
1901,  brings  out  clearly  the  variation  of  the 
arthritis  with  the  degree  of  infection.  The 
patient  was  a  female,  aged  26  years,  who 
was  suffering  from  bronchiectasis.  Six  months 
after  the  onset  of  the  illness  the  sputum 
became  offensive  and  more  copious ;  the  ankle 
joints  were  affected,  and  later  the  wTist  and 
other  joints.  The  interesting  point  about  the 
case  was  that  the  condition  of  the  joints  im- 


proved with  the  lessening  in  quantity  and  the 
decrease  in  foulness  of  the  sputum,  thiis  showing 
that  the  amount  of  arthritis  depended  upon 
the  amount  of  septic  absorption  that  was 
taking  place. 

Wirgmann  and  Turner  (66)  give  short  notes  of 
thirteen  cases  of  rheumatoid  arthritis  (?  in- 
fective arthritis)  in  all  of  which,  with  the 
exception  of  one,  ijyorrhoea  was  present.  In 
most  of  the  cases  chstinct  improvement  followed 
the  treatment  of  the  mouth. 

The  present  writer  was  consulted  seven  years 
ago  by  a  lady,  who  was  advised  most  strongly 
to  have  a  suppurating  tooth  removed  for  fear 
that  she  might  develop  arthritic  trouble.  The 
advice  was  not  followed,  and  she  subsequently 
developed  infective  arthritis  of  some  of  the 
inter-phalangeal  joints  of  her  left  hand.  The 
oft'ending  tooth  was  then  removed,  and  the 
joints  have  slowly  recovered. 

The  prognosis  in  these  cases  depends  very 
much  upon  the  time  the  disease  has  existed,  the 
capacity  for  recovery  of  the  patient,  and  the 
possibility  of  removing  all  sepsis.  As  a  general 
rule,  on  treatment  of  the  sepsis  the  disease 
becomes  stationary,  and  very  gradual  improve- 
ment follows.  So  important  are  these  cases, 
and  so  essential  is  it  to  deal  with  them  in  their 
early  stages,  that  septic  foci  in  the  mouth,  if 
they  do  not  immediately  respond  to  treatment 
by  conservative  methods,  should  be  dealt  with 
radically  by  the  removal  of  the  teeth.  Further, 
as  more  than  one  focus  of  infection  may  be 
present,  the  dental  surgeon  should  not  be 
satisfied  with  the  treatment  of  the  mouth  only, 
but  should  refer  his  patient  to  a  doctor,  especially 
in  the  case  of  married  women,  in  whom  the 
generative  organs  are  so  often  in  a  septic 
condition. 

(5)  Deformities  of  Weakness 

Under  this  heading  are  included  such  de- 
formities as  flat  feet,  scoliosis,  round  shoulders, 
and  genu  valgum,  due  to  loss  of  muscular  tone, 
which  is  determined  in  many  cases  by  septic 
(toxaemic)  absorption.  Fairbank  holds  that 
many  sources  of  infection  may  be  responsible — 
for  example,  sepsis  from  the  ear,  nose,  vagina, 
or  mouth,  the  most  important  of  these  being 
the  last.  Under  oral  sepsis  he  includes  septic 
tonsils  and  adenoids.  The  comiection  is  not 
always  easy  to  establish,  and  is  often  compli- 
cated by  gastric  ulcer,  dyspepsia,  constipation, 
anaemia,  and  want  of  fresh  aii'.  He  mamtains 
that  no  examination  in  these  cases  is  complete 
that  does  not  include  the  mouth,  and  no  treat- 
ment is  thorough  that  does  not  deal  with  it 
when  it  is  at  fault. 

Fairbank  finds  the  most  striking  example  of 
the  effect  of  oral  sepsis  in  cases  of  flat  feet 
occurring  in  young  men  and  lads  pur.suing  an 


708 


ordinary  healthy  Hfe,  %\ho  are  on  their  feet  all 
day,  but  ^Yho  are  not  shop-assistants,  and  thus 
compelled  to  stand  behind  a  counter.  In  such 
cases  he  almost  invariably  finds  oral  sepsis. 

Tlie  following  two  cases  are  of  interest  :  F.  H., 
female,  13  years  of  age,  came  to  Charing 
Cross  Hospital  on  February  13,  1909.  She 
complained  of  "  jjain  in  the  hips  and  across  the 
back,  and  of  her  joints  getting  set  and  preventing 
her  from  gettmg  up ".  Two-and-a-half  years 
ago  she  was  operated  on  for  genu  valgum.  On 
her  first  visit  she  looked  very  ill.  Her  femora 
were  markedly  curved.  She  had  double  coxa 
vara,  and  walked  with  a  rolling  gait  and 
apparently  with  some  pain.  Some  degree  of 
genu  valgum  was  still  present.  Severe  oral 
sepsis,  consisting  of  a  large  number  of  carious 
teeth  and  roots  with  surrounding  gingivitis, 
was  present.  Tlie  X-rays  showed  rickets  to 
be  still,  or  at  any  rate  recently,  active,  even  in 
the  latest-formed  portions  of  the  bones.  The 
late  rickets  was  presumed  to  be  due  to  the  in- 
fection from  the  mouth.  The  oral  sepsis  was 
treated,  and  the  child  sent  to  a  convalescent 
home  for  some  months,  with  marked  benefit. 

Male,  aged  21  years,  had  sufliered  from  sco- 
liosis and  fiat  feet  for  six  years.  He  was  pale, 
small  for  his  age,  and  young-looking.  He 
suSered  no  pain  except  when  ill  -svith  tonsilUtis. 
It  would  appear  that  the  pain  in  this  case  was 
due  to  the  action  of  the  toxin  on  the  supporting 
tissues. — H.  A.  T.  Fairbank. 

D.  Conditions  due  to  Infection  of  tlie  Tissues  by 
Bacteria  at  some  Point  or  Points  in  tlie  Oro- 
gastro-intestinal  Tract  (Septicaemic  States) 

(1)  Infective  Endocarditis. 

(2)  Septicaemia  and  Pyaemia. 

(3)  Subacute  Septicaemia  (?). 

(1)  Infective  Endocarditis 

In  1901  Henry  Jackson  gave  a  summary  of 
the  facts  connected  with  fifty-nine  cases  of 
malignant  endocarditis  occurrmg  in  the  Boston 
City  Hospital.  Li  these  fifty-nine  cases,  forty- 
three  of  which  were  confu-med  by  necropsy,  an 
aetiological  relationship  icas  only  found  in  fifteen 
cases.  Tliree  were  attributed  to  gonorrhoea, 
four  followed  childbirth,  four  were  associated 
with  foci  of  suppuration  (position  not  stated), 
and  one  each  was  attributed  to  tuberculosis, 
carbuncle,  pneumonia,  and  abscess. 

It  will  be  seen  that  Jackson  made  no  mention 
of  the  mouth  as  a  possible  source  of  infection, 
though  there  can  be  little  question  that  many 
of  the  cases  were  suffering  from  oral  sepsis. 
Any  source  of  infection  in  the  body,  whether 
it  is  situated  in  the  mouth,  the  ear,  the  urethra, 
or  elsewhere,  must,  in  the  absence  of  proof  to 
the  contrary,  be  taken  as  the  source  of  infection. 
The  following  case,  reported  by  William  Ewart 


(23),  is  one  of   extreme  importance  as  bearing 
uf)on  the  previous  statement. 

J.  C,  aged  26  years,  was  admitted  into 
St.  George's  Hospital.  Whilst  at  work  he  had 
had  a  sudden  seizure,  which  left  him  aphasic 
and  paralysed  on  the  right  side.  On  physical 
examination  nothing  abnormal  was  found  in 
the  chest  or  abdomen  except  a  slight  systolic 
murmur.  During  the  following  week  his 
temperature  oscillated  from  101''  or  100°  in  the 
evening  to  normal  in  the  mormng,  and  the 
pulse  and  resf)iration  gradually  rose  to  a 
maximum  of  120  and  34  respectively.  The 
diagnosis  remained  doubtful  until  the  dis- 
covery of  a  changing  and  increasmg  murmur 
defined  the  case  as  one  of  malignant  endo- 
carditis. No  improvement  took  place  under 
treatment.  Death  was  rather  sudden  and 
unexpected.  "  The  state  of  the  mouth  was 
unusually  bad.  Besides  stomatitis  there  was 
an  exceedingly  foul  condition  of  numerous 
stum23s.  The  odour  of  the  breath  was  intense, 
and  reminded  one  of  the  worst  smell  of  decaying 
and  macerating  dead  bones.  Some  of  the 
hollow  teeth  contained  plugs  of  offensive 
decomposing  material."  Ewart's  remarks  with 
reference  to  the  case  are  of  importance.  "The 
choice  lies  between  classing  it  in  the  group  of 
primary  or  '  idiopathic  '  cases,  because,  had 
aU  examination  of  the  mouth  been  omitted, 
no  disease  recent  or  old  would  have  been 
discovered  throughout  the  body;  or,  on  the 
other  hand,  giving  full  recognition  to  the  fact 
that  the  mouth  was  profoundly  diseased,  that 
it  was  infected  with  organisms,  and  that  it 
presented  large  ulcerated  surfaces  through 
which  access  to  the  circulation  must  have  been 
given  to  infection." 

Infective,  ulcerative,  or  malignant  endo- 
carditis, as  it  is  variously  called,  is  always  due 
to  infection  by  pathogenic  organisms.  The 
organisms  generally  found  are  the  staphy- 
lococcus pyogenes  aureus,  the  streptococcus 
pyogenes,  the  pneumococcus,  bacillus  coli, 
occasionally  bacillus  tuberculosis,  the  pneumo- 
baciUus,  bacillus  pyocyaneus,  baciUus  typhosus, 
and  certain  others.  "  The  primary  lesion, 
through  which  the  micro-organisms  enter  the 
blood-stream,  may  be  so  shght  as  to  escape 
observation ;  it  may  be  situated  in  any  portion 
of  the  alimentary,  respiratory,  or  genito-urinary 
tracts,  or  may  be  a  wound  of  the  skm ' '  (Mitchell 
Bruce,  Quain's  Dictionary  of  jiledicine).  It 
will  be  observed  that  most  of  the  organisms 
mentioned  above  have  frequently  been  demon- 
strated in  the  mouth ;  and  from  the  fact  that 
the  mouth  is  the  most  septic  part  of  the  body 
and  the  spot  \Ahere  slight  injuries  to  the  surface 
are  of  frequent  occurrence,  there  would  seem 
to  be  sufficient  evidence  to  prove  that  it  is  the 
most  frequent  source  of  infection  in  these  cases. 


709 


(2)  Septicaemia  and  Pyaemia 

(3)  Subacute  Septicaemia 

The  aetiology  of  septicaemia  and  pj-aemia  so 
closely  approximates  that  of  infective  endo- 
carditis that  it  is  not  considered  necessary  to 
discuss  their  relation  to  oral  sepsis.  Apart 
from  the  acute  forms  of  infection,  there  is  a 
large  class  of  diseases,  characterized  by  irregular 
temperature  of  long  duration,  to  wliich  no  cause 
can  be  assigned.  Many  of  these  cases,  in  the 
opinion  of  the  writer,  owe  their  origin  to  oral 
sepsis,  and  depend  upon  a  persistent  subacute 
infection  of  the  tissues.  For  convenience  they 
are  here  classified  under  the  title  of  Subacute 
Septicaemia. 

Smith  and  Barnes  (59)  give  a  ver\^  accurate 
account  of  a  case  suffering  from  oral  sepsis 
and  peculiar  general  symptoms,  of  which  the 
following  is  an  abstract — 

A  male,  aged  35,  who  had  travelled  a 
good  deal  in  the  British  Isles  but  never  abroad, 
had  enjoyed  good  health  except  for  several 
attacks  of  influenza  and  a  nervous  break-down 
at  the  age  of  16.  There  was  no  history  of 
rheumatism,  gout,  syphilis,  gonorrhoea,  or 
alcoholism.  On  March  27,  1909,  he  had  aching 
in  the  head,  back,  and  limbs.  He  was  better 
the  next  morning,  but  was  taken  iO  on  April  2 
with  \-iolent  headache.  From  this,  in  two 
davs.  he  recovered,  onlv  to  have  further  attacks 
on  the  9th,  12th  and  loth  of  the  month.  On 
the  16th  he  consulted  his  doctor,  and  gave  a  clear 
account  of  his  attacks,  \\hich,  he  said,  were  all 
aUke.  The  first  tiling  he  noticed  was  the 
appearance  of  a  red  spot  on  one  limb  (near  a 
joint),  which  enlarged  until  it  was  about  a 
quarter  of  an  inch  in  diameter.  At  first 
painless,  it  soon  began  to  burn,  and  then  the 
neighbouring  joint  became  painful  and  swollen. 
In  the  course  of  a  few  hours  he  felt  chilly,  and 
his  temperature  rose  to  103° ;  the  headache, 
the  temperature,  and  pain  then  increased,  and 
the  joint  could  not  be  moved.  About  one  hour 
later  perspiration  commenced,  at  first  slight, 
but  soon  so  profuse  that  the  bedclothes  were 
saturated  with  moisture.  With  the  onset  of 
perspiration  the  pain  became  less,  and  it 
vanished  in  about  an  hour,  whilst  the  perspu'a- 
tion  itself  continued  for  many  hours.  After 
an  attack  he  passed  a  good  night,  and  felt 
comparatively  well  next  morning. 

On  examining  the  patient,  the  tongue  was 
found  clean,  but  of  rather  brighter  red  than 
normal.  The  bowels  ^\ere  regular,  and  the 
urine  neutral  and  clear.  There  was  a  slight 
macular  rash  over  the  abdomen.  With  the 
exception  of  some  labial  herpes  there  were  no 
sores  of  any  description.  No  disease  in  the 
ears,  nose,  or  throat  was  found.  He  wore  a 
plate  of  artificial  teeth,  but  had  some  teeth  of 


his  owii,  which  were  carious  in  places,  and 
around  which  the  gums  were  retracted  and 
spongy.  He  was  considered  to  be  suffering 
from  rheumatism  and  treated  accordingly. 

Two  days  later  (April  18)  he  had  a  similar 
attack,  and  again  on  April  21  and  24.  On  the 
last  date  there  was  definite  swelling  and  fluctua- 
tion on  each  side  of  the  ligamentum  patellae, 
and  patches  of  erythema  were  present  on  various 
parts  of  the  body ;  there  was  a  soft  systohc 
murmur  at  the  apex ;  the  spleen  was  enlarged 
but  not  tender.  Blood  smears  were  examined ;  a 
leucocytosis  and  shght  eosinophiUa  (6  per  cent) 
were  present.  The  diagnosis  was  changed  to 
septicaemia,  with  infective  endocarditis,  and  it 
was  suggested  that  the  teeth  were  at  the  root  of 
the  matter.  He  was  treated  with  five-grain  doses 
of  sulphocarbolate  of  soda,  ordered  to  leave 
out  liis  denture,  and  given  a  mouth-wash  of 
permanganate  of  potash.  The  next  attack,  on 
April  27,  was  shghter,  the  pain  and  the  swelling 
being  in  the  left  heel.  After  this  the  attacks 
were  more  frequent  but  of  less  severity. 

From  May  3  onwards  the  teeth  were  removed 
at  intervals,  a  few  at  a  time.  After  the  removal 
of  the  last  tooth  he  had  no  further  attacks  and 
gamed  ground  rapidly.  Ten  days  later  he  was 
sent  to  the  seaside,  and  after  staying  there  a 
fortnight  he  returned  to  work  in  good  health, 
which  has  since  been  maintained. 

The  quartan  periodicity  of  the  attacks  is 
difiicult  to  explain,  and  made  it  necessary  to 
exclude  malaria  by  examination  of  the  blood. 
The  authors  consider  that  the  result  of  the 
treatment  offered  strong  e\-idence  of  the  im- 
portance of  the  oral  condition. 

This  case  is  very  carefully  reported,  and  is 
reproduced  here  rather  fully  because  it  brmgs 
out  certain  important  facts.  Although  the 
attempt  to  cultivate  an  organism  from  the 
blood  failed,  the  symptoms  most  certainly  point 
to  a  septicaemia.  The  result  of  treatment 
showed  that  as  the  condition  of  the  patient 
improved  pari  passu  ■\\itli  the  gradual  removal 
of  the  sepsis,  it  is  justifiable  to  deduce  that  the 
infection  was  a  continuous  one.  This  is  an 
important  point  not  only  serving  to  differentiate 
these  cases  from  acute  septicaemia,  in  wbich  the 
bodily  defences  are  supposed  to  be  suddenly  over- 
whelmed by  a  single  infection,  but  also  suggest- 
ing the  importance  of  the  treatment  of  the  mouth 
in  septic  diseases,  even  though  the  disease  may 
appear  to  be  definitely  established. 

Sidney  Spokes  (60)  records  the  case  of  a 
woman  who  \vas  considered  to  be  suffering  from 
enteric  fever.  The  temperature  oscillated  in  a 
remarkable  manner.  Streptococci  were  found 
in  the  blood.  She  was  at  the  same  time  suffer- 
ing from  a  general  pyorrhoea,  and  immediately 
began  co  get  better  after  the  removal  of  her  teeth. 


710 


E.  Diseases  Influenced  by  Oral  Sepsis 
It  has  been  pointed  out  several  times  through- 
out this  article  that  oral  sepsis  influences  the 
recovery  from  many  diseases,  more  especially 
in  cases  of  septic  gastro-enteritis,  pernicious 
anaemia,  clilorosis,  and  gastric  ulcer.  It  is  not 
necessary  to  pursue  this  argument  further, 
except  in  the  case  of  the  acute  specific  fevers. 

Hunter  (35)  has  carefully  worked  out  the 
influence  of  oral  sepsis  on  the  course  of  scarlet 
fever,  and  his  results  may  be  briefly  stated. 
He  believes  that  ^ihen  present  it 

(1)  Increases  the  severity  of  the  initial  angina  ; 

(2)  Determines  most  probably  the  secondary 

angina,      and      then      the      secondary 
adenitis ;    and 

(3)  Increases  the  severity  of  the  complica- 

tions. 

The  whole  question  of  the  relation  of  oral 
sepsis  to  the  acute  specific  fevers  requires  working 
out,  and  would  amply  repay  the  time  given.  It 
certainly  does  appear  probable  that  in  all  these 
diseases  oral  sepsis  may  be  an  important  factor, 
not  only  in  their  course,  but  in  their  incidence. 

The  recovery  from  most  di.seases  is  largely 
dependent  upon  a  healthy  state  of  the  gastro- 
intestinal tract ;  it  seems  reasonable,  if  on  this 
account  only,  to  say  that  oral  sepsis  influences 
for  the  worse  the  course  of  all. 

Conclusion 

The  above  account  of  the  relation  of  oral 
sepsis  to  diseases  of  the  body  does  not  in  any 
way  aim  at  being  exhaustive ;  an  endeavour 
has  only  been  made  to  give,  as  far  as  possible, 
a  comprehensive  view  of  the  whole  subject  and 
in  as  coherent  a  manner  as  possible.  The  some- 
what bizarre  nature  of  the  effects  that  have 
been  attributed  to  oral  sepsis  may  at  first  sight 
make  the  relationship  appear  improbable,  over- 
stated, and  even  ridiculous ;  but  when  once  the 
principles  that  underlie  the  subject  have  been 
grasped,  it  wUl  be  realized  that  the  conclusions 
are  a  necessary  outcome.  In  all  diseases  there 
are  always  two  factors  at  least,  the  seed  and 
the  soil,  %\'ithout  which  the  disease  cannot 
exist.  The  seed  varies,  the  soil  varies ;  never 
are  the  two  the  same ;  never  is  the  relation 
repeated.  This  is  why  variation  in  disease 
occurs,  and  in  no  two  persons  does  it  run  a 
precisely  similar  course.  Oral  sepsis,  let  it  be 
repeated,  is  but  a  comprehensive  term  to  include 
various  forms  of  septic  conditions  in  the  mouth  ; 
it-is  not  a  disease.  The  germs  causing  the  sepsis 
vary,  and  so  the  germs  passing  into  the  body, 
and  the  toxin  absorbed,  jjroduce  diff'erent  results 
in  different  people.  It  cannot  be  said  precisely 
why  germs  of  a  particular  kind  entering  one 
body  produce  a  septicaemia,  and  in  another  an 


infective  endocarditis ;  or  why  a  toxin  in  one 
will  produce  anaemia,  and  in  another  a  neuritis  ; 
that  such  is  the  case,  however,  seems  com- 
paratively certain,  and  one  must  rest  content 
for  the  moment  with  the  fact,  and  believe  that 
the  future  ^^ill  unfold  more  of  the  reason  \^hy. 

It  is  the  duty  of  every  medical  man  to  use 
to  the  best  of  his  ability  the  weapons  for 
fighting  disease  that  science  has  provided  for 
him ;  and  he  who  would  neglect  so  obvious  a 
one  as  the  prevention  and  treatment  of  oral 
sepsis  offer  is  neither  doing  justice  to  his  patient 
nor  to  his  profession.  No  doubt  the  time  will 
come  \\'hen  such  words  as  these  will  cease  to 
have  any  meaning ;  then  will  the  position  of 
oral  sepsis  as  a  factor  in  disease  have  been  fully 
recognized,  and  the  writing  of  such  a  chapter 
as  the  present  have  become  redundant. 

S.C. 

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CHAPTER    XLVII 

DENTAL    RADIOGRAPHY 


In  what  branches  of  dental  surgery  can  the 
X-rays  be  applied  for  diagnosis  ?  In  every 
branch  :  extraction,  filling,  periodontal  disease, 
orthodontics,  the  fitting  of  dentures  in  some 
cases  of  difficulty,  and  cases  of  pain  of  all  kinds 
possibly  referable  to  the  teeth ;  as  w  ill  appear 
in  the  following  pages. 

But  to  understand  radiographs  fuUy  and 
interpret  them  properly,  it  is  necessary  to  have 
some  knowledge  of  the  manner  in  ^\•llich  they 
are  taken,  and  a  short  description  will  therefore 
be  given. 

Although  the  therapeutic  use  of  the  rays 
forms  no  part  of  dental  work,  consideration 
of  the  subject  would  perhaps  appear  incomplete 
if  no  mention  were  made  of  it ;  for  at  the  present 
day  the  X-rays  are  not  only  of  tlierapeutic 
value,  but  their  power  can  be  accurately 
limited  by  filtration,  thus  enabling  the  operator 
to  reach  a  desired  depth  of  tissue  without  risk 
to  the  patient.  During  the  last  few  years 
some  alarm  has  been  caused  by  X-rays  causing 
burning,  etc.,  but  the  writer,  after  experience 
of  several  thousand  patients,  has  not  had  one 
case  of  burning  or  dermatitis. 

Wliat  tissues  will  the  X-rays  reveal  ?  Only 
such  as  wUl  be  wholly  or  partially  penetrated, 
or  such  as  will  stop  their  passage  more  or  less. 
It  may  be  taken  as  a  general  rule  that  bodies 
of  low  density  will  be  penetrated,  while  those 
of  higher  density  \nll  not  be  penetrated  at 
all,  or  only  partially.  Thus  rays,  even  of  low 
power,  will  penetrate  a  cork,  but  not  lead. 
Aluminium  will  be  penetrated,  but  not  lead  of 
the  same  thickness.  Hence  rays  that  will  just 
penetrate  the  soft  tissues  will  not  penetrate  the 
bone ;  or  if  more  powerful  will  penetrate  the 
bone,  but  not  the  tooth,  >inless  by  reason  of 
age  the.se  two  tissues  are  of  about  equal  density. 

Again,  what  constitutes  a  good  negative  ?  It 
must  exhibit  evidence  of — 

Absence  of  movement. 

Correct  penetration. 

Correct  exposure. 

Detail. 

Contrast — differentiation  and  condition  of 

tissues  (pathological  changes). 
Definition. 

Before  it  is  possible  to  interpret  a  radiograph 
properly,  it  is  necessary  to  be  able  to  recognize 


the  fulfilment  of  the  foregoing  requirements; 
and  in  the  following  jjages  the  descrif)tion  given 
of  radiographs  is  of  the  appearance  of  negatives 
only,  as  diagnosis  should  always  be  made  from 
such  and  not  from  prints,  details  being  often 
lo.st  in  the  latter,  and  errors  of  manipulation 
possibly  occurring. 

If  a  radiograph  (say,  of  the  side  of  the  face) 
shows  only  the  outline  of  the  soft  tissues,  and 
the  remainder  of  the  plate  uncovered  by  the 
face  is  black,  then  correct  or  over-exposure,  hut 
no  penetration  is  indicated.  If  deep-seated 
tissues  are  faintly  seen  (such  as  ethmoid  cells), 
and  the  whole  image  is  thin  and  white,  there 
has  been  good  penetration,  hut  insufficient  ex- 
posure. If  a  radiograph  is  black  or  very  dark 
all  over,  good  penetration  and  over-exposure 
have  occurred.  This  may  be  considered  a 
"  good  fault "',  as  reduction  of  the  negative 
is  possible. 

Penetration  combined  with  correct  exposure 
is  indicated  by  more  or  less  dark  shadows ;  a 
body  that  stops  the  passage  of  or  absorbs  the 
rays  (as  a  coin  or  bullet),  will  necessarily  appear 
as  a  perfectly  clear  shadow-.  It  is  owing  to 
this  fact  of  tissues  appearing  more  or  less  light 
(or  dark)  that  differentiation  is  possible — the 
enamel  from  the  dentine,  the  dentine  from  the 
pulp,  the  periodontal  membrane  of  the  tooth 
from  the  alveolus,  etc.,  atrophic  from  sclerotic, 
compact  from  cancellated  bone,  etc.  Detail, 
contrast,  and  definition,  are  especially  necessary 
in  dental  work. 

Movement  of  the  Patient  while  being  radio- 
graphed is  indicated  by  blurred  edges.  In 
examining  a  negative  it  is  well  to  see  if  the 
blurring  is  only  partial ;  for  instance,  if  sharp 
lines  and  good  definition  are  to  be  seen  in  the 
maxilla,  but  not  in  the  mandiljle,  then  it  is 
the  latter  only  that  has  moved,  while  change 
of  jjosition  during  the  exposure  will  l;e  shown 
by  a  double  image. 

Extensive  inflammation  may  produce  a 
somewhat  blurred  appearance  in  part  of  the 
negative,  e.  g.  much  infiltration  around  a 
molar,  owing  to  the  density  of  the  blood  and 
increased  thickness  of  the  tissues — the  perio- 
dontal membrane,  etc. 

Grey  negatives  are  caused  by  faulty  working 
of  the  apparatus,  giving  "  back  electro-motive 
force  "    (rever.sed  currents)   through   the  tube, 


712 


713 


the  effect  of  which  is  first  to  impress  the  image 
on  the  plate,  and  then  more  or  less  to  obliterate 
it. 

Penetration  through  a  space,  or  an  object  of 
low  specific  gravity,  such  as  rarefied  bone, 
causes  a  dark  shadow;  thus,  a  cavity  in  bone, 
the  palatal  suture,  the  frontal  sinus,  the  mandi- 
bular foramen  (if  end  on),  and  the  inferior  alveolar 
canal,  will  appear  more  or  less  dark.  On  the 
other  hand,  little  or  no  penetration  through  an 
object  of  high  specific  gravity  causes  a  light 
shadow;  thus,  edges  of  bones,  compact  bone, 
the  mylo-hyoid  ridge,  and  the  external  oblique 
ridge  of  the  mandible,  and  especially  fillings, 
crowns,  etc.,  wiU  appear  more  or  less  as  light 
shadows. 

The  foregoing  may  easily  be  remembered  by 
the  following  mnemonic  : — 

Penetration       =  dark  shadow — Pendash. 
/mpenetration  =  light  shadow — Impish. 


Dark  Shadows 

All  cavities  and  all  sinuses 
(normal  and  pathologi- 
cal). 

Soft  tissues. 


Light  Shadows. 

Cancellated  bone. 

Compact  bone. 

Enamel. 

Some  root-f311ings. 

Gutta-percha  points. 

All  metals. 


In  each  column  the  materials  are  arranged  in  order, 
from  darker  to  lighter,  from  above  downwards. 

Taking  Film  Radiographs  in  the  Mouth. — As 
the  rays  have  only  one  side  of  the  face  to 
penetrate,  a  somewhat  soft  tube  should  be 
used ;  and  one  with  a  spark  gap  of  two  and  a 
half  to  three  inches,  with  a  secondary  current 
of  about  two  to  three  milliamperes,  \vill  give 
good  results  in  six  to  ten  seconds,  the  tube  being 
at  a  distance  of  about  twelve  inches.  It  is  not 
possible  to  give  more  exact  figures  as  each 
case  must  be  taken  on  its  own  merits.  Finer 
detail  can  be  obtained  by  more  rapid  exposures, 
and  with  a  current  of  about  ten  milliamperes 
exposures  can  be  made  in  one  second. 

The  writer  usually  employs  a  larger  current 
than  this,  giving  an  exposure  of  about  ^  of  a 
second.  Wien  an  intensifying  screen  is  used 
the  exposure  is  about  ^  of  a  second — practically 
instantaneous. 

Tlie  film  is  doubly  wrapped  in  black  paper 
and  then  again  m  gutta-percha  tissue.  The 
black  paper  has  a  deteriorating  effect  on  the 
emulsion,  so  the  films  must  not  be  kept  \\Tapped 
for  any  length  of  time — say  a  month — as  they 
are  then  unreliable.  Austin  Edwards'  Double 
Instantaneous,  Lumiere's  Extra  Rapid  Vitrose 
Flat  Films,  and  Hford  Special  X-rays  Films, 
are  very  good.  In  looking  for  small  objects 
the  ^vrite^  finds  it  good  practice  to  use  films 
of  different  makes  for  the  same  case. 

There  are  several  ways  of  holding  them  in 
the  mouth ;  the  most  usual  is  for  the  patient 
23* 


to  hold  them.  If  the  mandible  is  being  radio- 
graphed, he  uses  the  first  finger  of  the  hand 
opposite  to  the  side  taken,  closing  the  teeth 
gently  on  the  finger  to  aid  steadiness.  In  the 
case  of  the  maxilla,  he  can  hold  the  film  with 
the  thumb,  the  fingers  resting  on  the  cheek. 
But  the  patient  cannot  always  be  relied  on  to 
do  this ;  he  may  be  a  little  nervous  and  shaky, 
«hile  some  are  so  clumsy  as  to  be  quite  unable 
to  do  anything  of  the  kind.  For  little  children 
the  parent  or  friend  may  do  it.  If  the  film  must 
be  held  by  some  one  other  than  the  patient,  for 
the  maxilla  he  must  stand  at  the  back  of  the 
chair,  holding  the  film  up  with  the  forefuiger; 

B 


Fig.  9.32. 
A  Represents  film  holder  for  tlie  premolar  and  molar 
region  for  use  on  either  side  of  the  mandible. 

(1)  Shows  position  of  the  hard  wood  fastened  by 

means  of  screws. 

(2)  The  extension. 

B  Represents  the  film'  holder  for  the  premolar  and 
molar  region  in  the  maxilla. 

C  Holder  for  incisor  or  canine  region  in  the  maxilla. 
D  Holder  for  incisor  or  canine  region  in  the  mandible. 

for  the  right  side  he  uses  the  forefinger  of  the 
left  hand,  and  vice  versa.  On  account  of  the 
risk  of  dermatitis,  etc.,  this  should  not  be  done 
by  any  assistant  constantly  working  with  the 
X-rays. 

A  film  holder  has  long  been  a  desideratum, 
and  the  \^Titer  has  designed  a  sterilizable  holder 
that  has  proved  very  useful.  It  is  made  of 
pewter  about  ,'j  inch  thick,  bent  at  right 
angles,  and  attached  by  screws  to  a  piece  of 
wood  or  insulating  fibre  about  J  inch  wide 
and  wedge-shaped.  At  the  angle  there  is  a 
space  of  about  J-  inch,  in  which  the  film  is 
placed,  and  by  pinching  the  holder  it  is  easily 
held  firm.  There  is  also  a  wire  extension, 
^^'hich   the   patient   can   bite   upon,   and    thus 


714 


press  the  film  close  to  the  gum.  \\1ien  one  side 
of  either  jaw  is  being  radiographed  this  extension 
is  on  the  opposite  side ;  in  the  case  of  the  upper 
incisor  region  there  is  an  extension  backwards 
for  the  lower  teeth  to  bite  upon.  To  sterilize 
the  holder  it  is  necessary  to  boil  for  half  an 
hour,  as  the  wood  or  fibre  is  absorbent  and  a  poor 


t\\o  transparent  superimposed  1)odies  of  simila- 
shape  are  viewed  from  the  front  it  is  difficult 


Fig.  933. 

If  the  two  objects  A  and  B  are  viewed  from  the  point 
C,  one  obscures  the  otlier ;  but  if  viewed  from  the  side, 
as  at  M,  then  both  come  into  view.  The  third  position 
at  D  is  only  necessary  to  confirm  tlie  position  of  A 
and  B. 

conductor  of  heat.  To  use  it,  the  film  is  placed 
in  the  holder,  which  is  then  placed  in  the  mouth, 
the  patient  biting  on  it  firmly. 

Three-Position  Method. — This  is  a  most  useful 
method  with  nervous  or  fidgety  cliildren  who 
cannot  keep  still  long  enough  for  stereoscopic 
negatives  to  be  taken.     It  is  usually  employed 


In  this  case  a  second  right  upper  incisor  and  supernmnerary  are 
superimposed  :  it  was  desired  to  remove  the  one  that  had  the 
weaker  root.  Radiograph  C  (taken  centrally)  sliows  the  two  teeth 
overlapping,  the  double  image  giving  a  lighter  shadow  owing  to 
less  penetration.  Both  roots  have  open  apices,  and  there  is 
nothing  to  choose  between  them.  The  radiograph  taken  distally 
shows  that  ono  of  the  teeth  ha.s  come  more  into  view,  this  is  the 
one  situated  palatally. 


Unerupted  Upper  Canine. 

In  the  central  radiograph,  C,  the  canine  is  nearer  the 
first  premolar  than  the  lateral,  but  in  the  distal  radio- 
graph. D,  it  is  seen  to  be  more  forward  towards  the 
lateral;  it  is  therefore  situated  labially  (confirmed  by 
the  medial  radiograph,  M ). 

to  say  which  of  the  two  is  in  front  of  or  behind 
the  other,  but  if  viewed  from  either  side  both 
come  into  view. 

If  two  tumblers  are  placed  together 
line  behind  the  other,  the  one  in  front 
obscures  the  view  of  the  one  behind,  but 
if  a  lateral  view  is  taken  both  come  into 
view.  The  object  in  front  is  always  in  view 
whether  viewed  from  the  front  or  the  side, 
and  it  is  the  object  at  the  back  that  {appar- 
ently) moves  forward  when  viewed  laterally. 
A  radiograph  is  taken  \\'itli  a  film  in 
the  mouth  as  nearly  as  possible  over  the 
region  about  which  information  is  re- 
quired ;  this  must  be  marked  "central  ". 
Another  film  radiograph  is  taken  a  little 
to  one  side  of  the  central  position,  and 
if  nearer  to  the  median  line  of  the  mouth 
is  marked  "medial".  A  third  film  is 
exposed  a  little  to  the  other  side  of  the 
position  of  the  "  central  "  radiograph, 
and  if  further  from  the  median  line  is 
marked  "  distal ". 

As  far  as  possible  they  should  all  be 
taken  on  the  same  plane. 


in  cases  of  superimposed  teeth,  supernumeraries, 
and  unenipted  canines. 

The  principle  of  the  method  is  this,  that  if 


STEREOSCOPES 

The     Wheatstone    Stereoscope. — This     instru- 
ment  for    viewing   negatives   consists   of   two 


'15 


negative  holders  or  lanterns  mounted  on  a 
board  about  three  feet  long.  Each  of  the 
holders  has  an  electric  bulb  to  illuminate  the 
negative ;  the  light  passes  through  ground 
glass  so  as  to  diffuse  the  light  equally,  this 
being  of  the  utmost  importance.  Midway 
between  the  negative  holders  is  a  double  plane 
mirror,  each  mirror  being  fitted  at  right  angles 
with  the  other  and  at  45  degrees  with  the 
holders ;  the  mirrors  are  mounted  on  a  pillar, 
which  slides  to  and  fro  for  the  purpose  of 
adjusting  the  focus.  A  ''  resistance  "  for  each 
lamp  is  also  fitted,  so  that  if  a  negative  is  thin 
the  light  can  be  reduced ;  but  if  the  negative  is 
dense  then  the  full  light  obtainable  can  be  em- 
ployed. Wire  filament  lamps  of  about  50  c.p. 
are  the  best,  owing  to  the  small  amount  of 
heat  given  ofi^. 

Owing  to  the  difficulty  of  viewing  negatives 
when  wet  for  a  sufficient  length  of  time,  on 
account  of  the  heat  and  other  causes,  the  writer 
has  devised  glass  cells  to  contain  water,  which 
are  suspended  to  the  lanterns  and  in  which 
the  negatives  are  placed. 

The  negative  marked  ''left"  is  placed  in 
the  holder  on  the  left  side  of  the  observer,  and 
the  "  right  "  negative  on  the  right.  The  ob- 
server must  look  quite  close  to  the  mirror  so 
that  he  sees  the  reflection  of  each  negative  in 
the  mirrors.  If  the  observer  is  accustomed 
to  spectacles,  he  must  use  those  intended  for 
reading. 

Now  if  the  observer  draws  the  mirror  pillar 
towards  himself,  he  wdl  see  two  separate  views, 
but  on  sliding  the  mirror  from  him  he  \\  ill  find 


m 


close  to  the  :nirror,   with  his  nose  practically 
touching. 

But  it  may  happen  that  although  he  sees  a 
part — say  the  mandible — in  stereoscopic  relief, 


Fig.  'J'M'k — Metluid  of  using  the  Wlii-'atsluiiu 
stereoscope. 

— presuming  that  the  negatives  have  been 
properly  placed  in  the  holders — the  views  blend 
into  one,  and  on  pushing  the  mirror  a  little 
further  still  he  will  be  able  to  see  the  view 
stereoscopically.     He  nuist  ahvays  keep  quite 


Fig.  937. — Method  of  viewing  stereoscopic-ally  without 
a  stereoscope. 

the  upper  portion  is  not  quite  so  good.  This 
can  be  remedied  by  manipulating  the  screws 
attached  to  the  negative  holders,  so  as  either 
to  raise,  lower,  or  tilt  forwards  or  sideways. 

Now  if  the  plates  are  placed  in  the  negative 
holders  film-side  outwards,  they  are  being 
viewed  as  though  the  observer  were  standing 
on  the  same  side  of  the  patient  as  the  plates 
were  placed.  For  instance,  if  the  plates  were 
placed  against  the  left  side  of  the  patient  (the 
X-rays  tube  would  then  l)e  on  the  right),  then 
on  placing  them  in  the  Wheat  stone  stereoscope 
film-side  outwards,  the  observer  will  view  them 
as  though  standing  and  facing  the  patient  on 
the  left  side.  Tlie  same  will  of  course  hold 
good  in  each  respect  for  the  right  side. 

But  if  the  plates  are  placed  in  the  stereo- 
scope film-side  inwards,  then  they  are  viewed 
as  though  the  observer  were  on  the  same  side 
as  the  X-rays  tube  when  the  radiograph  was 
taken.  That  is  to  say,  if  the  plates  (as  above) 
were  placed  against  the  left  side  of  the  patient 
(X-rays  tube  on  the  right),  then  on  placing 
them  in  the  stereoscope  film-side  inwards,  the 
position  is  the  reverse  of  the  above,  and  they 
are  being  viewed  as  though  the  observer  were 
on    the    right    side    of    the    patient.      This    is 


716 


entirely  due  to  the  fact  that  reflections  of  the 
negatives  are  being  viewed.  It  is  most  im- 
portant that  care  be  taken  in  properly  placing 
the  plates,  as  it  is  possible  for  a  buried  object 
to  be  described  as  being  on  the  left  side  when 
as  a  matter  of  fact  it  is  on  the  right  side,  or 
vice  versa  ;  and  also  that  they  be  viewed  both 
ways — film-side  inwards  and  outwards.  More- 
over, by  rotating  the  lanterns  a  little  (keeping 
the  plates  parallel)  the  stereoscopic  effect  is 
rendered  more  apparent. 

The  side  of  the  jjationt  on  which  the  plate 
was  placed — right  or  left — is  readily  founcl,  as, 
of  course,  the  film-side  is  towards  the  patient 
when  the  exposure  is  made. 

If  no  stereoscope  is  obtainable,  the  plates 
may  be  viewed  in  the  following  manner. 

Hold  the  negatives  in  the  left  hand  against 
a  mndow  so  as  to  have  a  good  diffused  light, 
lowering  the  blind  to  prevent  superfluous  light 
striking  the  eye.  The  left  negative  must  be 
opposite  the  left  eye  and  the  right  opposite 


Fig.  938, 

the  right  eye,  and  the  film-side  of  each  towards 
the  observer.  Now  hold  up  the  forefinger  of 
the  right  hand  a  few  inches  from  the  negatives, 
and  look  steadily  at  the  top  of  it ;  thiee  views 
are  to  be  seen,  of  which  the  central  one  is  in 
stereoscope.  A  little  practice  may  perhaps  be 
necessary  for  this. 

Another  method,  of  course,  is  to  reduce  the 
negatives  and  place  in  an  ordinary  photo- 
graphic stereoscope,  but  time  will  not  always 
allow  this  to  be  done.  It  has  the  advantage  of 
making  the  image  very  much  sharper. 

It  is  most  essential  that  radiographs  should 
be  evenly  illuminated ;  opal  glass  always 
intervenes  in  stereoscopes  or  negative-viewers 
for  this  purpose.  The  Pirie  Stereoscope  (see 
Fig.  938)  somewhat  resembles  an  opera-glass, 
consisting  of  two  united  aluminium  tubes,  in 
one  of  which  a  double  reflecting  jarism  is  placed. 

The  negatives  are  taken  in  the  usual  way, 
and  are  placed  side  by  side  in  illuminated 
negative-viewers  or  in  a  window,  film-side  from 
observer ;  the  right  plate  is  to  be  viewed  by  the 
right  eye  and  the  left  by  the  left  eye.     They 


should     also,    if    possible,    be    slightly    tilted 
towards  each  other. 


DIAGNOSIS  BY  MEANS  OF  X-RAYS 
Presence  or  Absence  of  Teeth 

The  primary  use  of  the  X-rays  in  dental 
surgery  is  to  ascertain  the  presence  or  absence 
of  teeth  and  buried  roots,  and  if  present  their 
position. 

The  teeth  usually  to  be  sought  for  are — 

(1)  Third  molar,  both  maxillary  and  mandi- 

bular. 

(2)  Premolar,  maxillary  and  mandibular. 

(3)  Canine,  usually  maxillary. 

(4)  Lateral  incisor,  usually  maxillary. 

(5)  Central  incisor,  mandibular  (very  rare). 

(6)  Buried  roots. 

(7)  Supernumerary  and  supplemental  teeth. 

(1)  Third  Molar. — The  reasons  for  ascertain- 
ing the  presence  or  absence,  or  the  position, 
of  this  tooth  are  as  follows  : — 

(a)  Intractable  Neuralgia  (query  trigeminal). 
— If  the  tooth  is  found  to  be  present  by  the 
ordinary  means,  but  is  impacted  or  displaced, 
then  it  may  be  necessary  to  ascertain  its  position 
in  relation  to  the  ascending  ramus  and  the 
second  molar ;  and  also  to  the  inferior  alveolar 
nerve,  in  mandibular  cases ;  or  w  hether  it  is 
exostosed. 

(6)  Extraction  or  Preservation  of  First  Per- 
manent Molars. — It  may  be  necessary  to 
ascertain  the  presence  and  good  position  of 
the  third  molar  in  children  of  ten  to  twelve 
years  of  age  or  so,  if  the  mouth  is  crowded, 
and  the  first  permanent  molar  is  very  carious, 
and  its  retention  therefore  a  matter  for  coa- 
sideration. 

Probably  eight  years  of  age  is  the  earliest 
period  at  which  the  calcifying  tooth  can  be 
seen,  although,  of  course,  if  it  is  not  to  be  seen 
at  that  age,  this  is  not  conclusive  proof  that  it 
will  not  subsequently  develop.  It  is  usually 
seen  in  its  earliest  stage  as  a  light  shadow,  the 
shape  of  a  thin  masticating  surface,  apparently 
floating  at  the  surface  of  a  cavity  ^^ith  well- 
defined  margins,  viz.  the  crypt.  Earlier  still 
the  crypt  only  is  to  be  seen. 

Undoubtedly  the  best  method  of  radio- 
graphing the  third  molar  is  by  means  of  a 
plate  externally,  preferably  the  size  known  as 
"  whole  plate  " ;  it  should  be  taken  stereo- 
scopically. 

If  the  condition  on  one  side  only  is  desired, 
then  that  side  should  be  tilted  downwards  so 
as  to  escape  any  confusion  with  the  other 
side,  and  the  mouth  propped  open  by  a  cork. 
But  if  all  four  third  molars  are  desired,  this 
should  not  be  done,  owing  to  the  difficulty  that 


Jll 


sometimes  exists  in  interpreting  the  radiograjsli 
if  the  head  is  jDlaced  in  a  wholly  unnatural 
position;  a  little  tilting,  howev^er,  is  advisable, 
and  the  X-rays  tube  should  be  placed  about 
three  feet  from  the  plate  ;  or  both  sides  may  be 
radiographed  separately  stereoscopically. 

(2)  Premolar. — -Probably  these  teeth  are  more 
often  missing  from  the  mandible  than  the 
maxilla.  Cases  will  occur  \\here  a  deciduous 
molar  is  uiiduly  retained,  and  having  become 
carious  would  be  extracted,  instead  of  being 
filled,  if  it  were  quite  certain  that  a  premolar 
existed.  In  the  opinion  of  the  writer  it  is  very 
doubtful  whether  a  premolar  exists  if  the 
deciduous  molar  is  retained  after  twenty-five 
years  of  age.  Up  to  that  age  it  is  an  open 
question,  and  the  presence  of  the  tooth  in  the 
alveolus  must  not  be  assumed  because  there 
is  a  good  space  between  the  first  premolar  and 
first  molar  after  the  deciduous  molar  lias  been 
lost.  Wliat  might  happen  in  these  days  of 
compensation  if  a  deciduous  molar  were  ex- 
tracted in  the  hope  of  a  premolar  erupting, 
and  it  never  appeared,  can  easily  be  imagined ; 
l>ut  the  question  whether  a  tooth  does  or  does 
not  exist  can  be  decided  positively  by  means 
of  a  radiograph.  It  has  been  shown  that  ab- 
sorption   of    the    deciduous    teeth     may    take 


Fig.  939. — Position  for  i-adiograplmig  Third  Mandibular 
Molars. 

place    without    the    presence    of    a    permanent 
tooth. 

The      cases     requiring     elucidation     are     as 
follows  : — 

(a)  Persistent  deciduous  tooth  in  a  normal 

arch. 
(t)  Crowded   arch,    and   only   one   premolar 
present  on  either  side  of  either  jaw. 


(c)  In  mandible  :  whether  both  premolars  are 
present  in  cases  of  "fanned  "  incisors, 
and  the  position  of  the  buried  teeth  if 
present. 

{d)  In  adults  :  large  space  between  first  pre- 
molar and  first  molar. 

(e)  Cause  of  sub-lingual  swelling  in  premolar 
region. 


Fig.  910.- 


-Two  cases  of  Missing  Second  Lower 
Premolars. 


In  (1)  |467  and  part  of  3  are  shown  in  film.  ,67 
have  apices  undeveloped,  and  the  larger  sized  pulp  in 
i?  as  compared  with  6  is  noticeable.  The  dark  line 
representing  the  periodontal  membrane  at  the  distal 
aspect  of  the  posterior  root  of  G  is  well  marked,  as  well  as 
the  light  line  next  to  it  representing  the  compact  bone. 
A  little  tartar  is  also  to  be  seen  at  the  cervical  edge 
of  |6.  The  square  appearance  of  the  alveolus  between 
the  teeth  is  normal. 

In  (2)  this  is  also  shown ;  in  4  there  is  a  distal  cervical 
cavity,  and  tartar  also  on  g  . 

Films  will  be  sufficient  when  taking  this 
region  in  most  cases ;  and  in  children  usually 
give  the  most  pleasing  results,  owing  to  the 
amount  of  contrast  that  can  be  obtained.  But 
plate  negatives  taken  stereoscopically  are  more 
useful  as  showing  the  general  condition  of  the 
whole  of  the  jaws. 

(3)  Canine. — Although  it  is  not  uncommon 
for  these  teeth  to  be  missing  from  the  arch, 
it  very  rarely  happens  that  the  radiograph 
proves  them  to  be  absent  from  the  jaws. 
They  may  remain  unerupted  for  years  and  be 
quite  out  of  their  position,  but  the  wTiter  has 
only  met  with  two  cases  where  they  were  absent 
froin  the  maxilla,  and  no  case  of  absence  from 
the  mandible. 


718 


Upper  Canine. — In  normal  cases  the  develop- 
ing maxiUary  canine  is  to  be  felt  as  a  liard 
swelling  over  the  root  of  the  deciduous  canine, 
but  when  they  are  delayed  in  erupting  various 
signs  may  present  themselves. 

(a)  A  little  swelling  on  the  palate  may 
appear.  It  may  then  be  assumed  that 
the  tooth  is  present,  and  it  is  only 
necessary  to  ascertain  its  position  and 
thus  decide  future  treatment. 

{h)  The  swelling  may  be  so  sliglit  as  to  be 
scarcely  palpable,  and  it  is  necessary 
to  determine  whether  the  tooth  is 
present  at  aU,  and  if  so  its  position. 

Tlie  wTiter  had  one  case  where  there  was 
absolutely  no  indication  whatever  of  any  canines 


Fig.  941. 

being  present,  as  determined  by  the  usual 
clinical  means,  the  alveolar  ridge  being  unusually 
thin,  with  good  arch  and  deep  palate.  The 
X-rays  showed  the  presence  of  both,  and  also 
their  position. 

Tlie  most  usual  position  of  an  unerupted 
upper  canine  is  on  the  palate,  pointing  to  the 
lateral  or  even  the  central,  the  cusp  of  the 
tooth  being  perhaps  close  to  the  cervical  edge 
of  an  incisor,  or  even  as  high  up  as  its  apex. 
It  happens  more  often  than  not  that  both 
canines  are  unerupted. 

Upper  canines  may  be  radiographed  on  films 
or  plates,  and  some  dentists  prefer  films  to 
plates,  but  the  writer  considers  that  when 
possible  they  should  be  taken  stereoscopically, 
and  on  both  sides  of  the  maxilla.  It  is,  how- 
ever, a  very  difficult  position  to  radiograph  on 
plates.  If  the  arch  is  narrow  or  contracted  the 
radiograph  may  be  taken  on  plates  from  the  side 


of  the  face  ;  but  if  it  should  happen  to  be  wide — 
more  especially  if  it  has  nearly  parallel  sides 
— then  it  should  be  radiographed  postero- 
anteriorly,  the  rays  being  directed  diagonally 
and  upwards  between  tlie  spine  and  the  ascend- 
ing ramus. 

Another  position  is  shown  in  Fig.  941,  the 
head  being  tilted  downwards,  and  the  plate,  of 
cour.se,  being  in  front  of  the  face,  and  the  X-rays 
directed  postero -anteriorly  and  upwards,  with 
the  anti-kathode  opposite  the  spinal  column ;  a 
cork  props  the  mouth  open.  Both  upper  and 
lo«er  jaws  are  obtained,  as  well  as  the  nasal 
cavity.     The  unerupted  teeth  to  be  seen  are — 

7543  I  3457 


75432  I  23457 


If  films  are  used  in  either  of  the  above  con- 
ditions, then  they  must  be  taken  by  the  "  three- 
position  method  "  already  described,  one  flat 
film  being  of  very  little  service ;  and  also  with 
a  film  across  the  maxilla  and  the  rays  directed 
vertically  downwards  over  the  nose. 

The  appearance  of  the  canine  in  the  radio- 
graph requires  no  description. 

Another  method  of  ascertaining  the  position 
of  an  unerupted  tooth  is  to  make  a  wire  frame 


Fig.  04  2. 


-A  niethucl  of  ascertaining  tlie  position  of  an 
unerupted  tooth. 


or  plate,  having  a  wire  about  four  inches  long 
projecting  througli  the  lips.  The  frame  is 
purposely  made  of  an  irregular  shape.  It  is 
placed  in  tlie  mouth,  and  the  projecting  wire 
is  bent  to  the  angle  at  whicli  it  is  intended  to 
direct  the  X-rays.  A  film  radiograph  is  taken 
with  tlie  frame  in  situ,  as  shown  in  Fig.  942. 

Tlie  position  of  the  canine  is  seen  and  can  be 
marked  on  the  model.  In  the  figure  the  project- 
ing wire  is  seen  over  one  of  the  incisors  and 


'19 


appears  quite  short  (although  it  was  four  or 
five  inches  long),  owing  to  the  rays  being 
directed  very  nearly  in  the  exact  direction  of 
the  wire. 

This  method  is  somewhat  troublesome,  and 
should  oiJy  he  adopted  when  better  means 
are  not  available. 

In  a  case  of  a  lady  of  middle  age,  an  upper 
canine  had  given  a  great  amount  of  pain,  and 
although  seen  in  the  radiograph  to  be  unob- 
structed and  perfectly  vertical,  it  never  came 
down  into  its  place. 

A  lad  of  sixteen  suffered  great  pain  from  a 
canine  in  the  right  maxilla,  which  had  erupted 
a  very  little  in  the  incisor  fossa.  Previous  to 
operating  it  was  necessary  to  ascertain  the  f)osi- 
tion  of  the  root,  and  also  whether — a  point 
of  more  importance — it  was  of  normal  shape. 


Fig.  !I43. — UncruptL'd  Lower  Cauiiiu. 

Tlie  X-rays  showed  the  tooth  to  be  fully 
developed  and  of  normal  sliape,  but  lying 
parallel  with  the  floor  of  the  maxillary  sinus. 
Considerable  difficulty  was  anticipated  in  the 
extraction,  but  after  several  attempts  to  dis- 
place it,  it  came  away  with  surprising  ease  on 
being  rotated  with  straight  forceps. 

Lower  Canine. — These  remain  much  less 
frequently  unerupted ;  but  the  writer  has  had 
a  case  where  the  tooth  was  lying  quite  hori- 
zontally on  the  inner  side  of  the  mandible, 
and  another  in  which  it  was  directed  outwards 
and  downwards.  The  usual  reason  for  radio- 
graphing them  is  in  case  of  '"  fanned  "  incisors, 
to  ascertain  how  much  pressure  is  being  caused 
by  the  canines.  They  can  be  radiographed 
in  the  same  manner  as  the  upper,  but  stereo- 
scopic plates  are  better. 

In  Fig.  943  an  unenipted  lower  canine  is 
seen   taken   diagonally  and   postero-anteriorly. 


Fig.  944,  taken  with  a  film,  shows  the  canine 
pressing  against  the  root  of  the  lateral;  ai)ove 
the  canine  an  absorbed  area  is  seen. 

(4)  Upper  Laterals. — Film  radiographs  usually 
.suffice  to  show  the  presence  or  absence  of  these 
teeth  ;  but  if  t)y  reason  of  fiat  palates  and  teeth 
much  displaced,  a  satisfactory  film  radiograph 
cannot  be  taken,  then  it  must  be  done  diagon- 
ally and  postero-anteriorly,  /.  e.  by  rays  directed 


Fig.  944.— Uiuruplcd         Fig.  !I45.— Aca.seoi  .A.ljsciit 
Lower  Canine.  Lower  Central.s. 

between  the  vertebrae  and  ascending  ranuis  on 
the  opposite  side. 

(5)  Loicer  Centrals. — These  may  also  be 
taken  with  films  ;  but  it  will  occasionally  happen 
that  the  sulcus  between  gum  and  tongue  is  so 
shallow  as  to  prevent  the  film  being  placed 
over  the  apices ;  in  these  circumstances  the 
postero-anterior  position  is  necessary,  with  the 
tube  as  close  as  possible  to  the  patient,  so  as 
to  obliterate  the  shadow  of  the  spinal  column. 

Radiograph  (Fig.  945)  show  s  absence  of  central 
incisors  :  the  second  incisors  with  root-canals 
showing,  are  seen  to  have  open  apices ;  the 
dark  line  close  to  the  cementum  is  the  perio- 
dontal membrane,   while   next  to  it  is  a  light 


Fig.  <)4il 


l:iin.d    I 


lusually  deep. 


line  representing  the  compact  bone  of  the 
socket.  The  deciduous  centrals  show  no  sign 
of  absorption.  One  of  the  canines  is  seen 
erupting  with  an  area  of  absorption  above  the 
cusp,  together  with  absorption  of  the  deciduous 
canine. 

(6)  Buried  Roots. — The  necessity  of  ascer- 
taining the  presence  of  roots  very  frequently 
happens,  as  they  may  give  rise  to  the  following 
conditions. 


720 


(a)  Pain  on  one  Side  of  the  Face. — Tliis  in- 
definite description  so  often  given  by 
the  patient  may  cause  much  difficulty 
in  diagnosis.  After  all  the  usual  means 
of  diagnosis  have  been  exhausted  as 
weU  as  the  usual  remedies  for  relief, 
it  may  then  be  found  on  radiographing 
the  patient  that  a  buried  root  exists  in 
the  jaw. 


Fig. 


'J47. — Filin  Radiograph  u£  Kuut  m  llie  Maxillary 
Sinus. 


(b)  Sinuses  at  almost  any  part  of  the  mouth 

may  also  be  due  to  the  same  cause. 

(c)  Neuralgia. — Pain   felt   at   certain    points 

may  indicate  a  particular  tooth  ap- 
parently absent ;  the  root  of  this  tooth 
may,  however,  be  in  the  jaw. 

(d)  Infected    Maxillary    Simis.  —  As  is 

well  knowii  to  rhinologists,  the 
apices  of  the  molars  and  premolars 
often  push  up  the  floor  of  t\w 
sinus  so  as  to  form  several  emin- 
ences;  hence  the  ease  with  whicli 
an  unsuspected  root  may  keep  up 
infection  and  render  treatment 
nugatory. 

(e)  Pain  on    Wearing  Dentures  is   fre- 

quently caused  by  a  buried  root. 
No  trouble  whatever  may  be  ex- 
perienced by  the  patient  initU  a 
denture  is  worn,  when  pain  is 
wrongly  attributed  to  the  denture  ; 
it  may  then  be  found  on  radio- 
graphmg  the  patient  that  a  little 
piece  of  root,  which  has  been 
quiescent  for  possibly  as  long  as 
twenty  years,  is  the  whole  cause  of  the 
trouble. 


may,  perhaps,  only  be  distinguished  from  the 
surrounding  tissues  either  by  their  presence 
more  or  less  above  the  alveolar  line  ;  or  if  below 
the  alveolar  line,  by  the  dark  line  indicating  the 
periodontal  membrane. 

Again,  the  root  may  be  so  small  and  thin  that 
its  density  (radiographicaUy)  and  that  of  the 
alveolus  become  the  same  or  nearly  so.  Hence 
there  is  sometimes  a  difficulty  in  giving  a 
negative  report ;  in  any  case  it  should  not  be 
given  until  the  film  or  plate  is  quite  dry,  as 
owing  to  the  swollen  state  of  the  emulsion 
when  wet,  portions  of  roots,  easily  seen  after- 
wards, may  not  be  discerned  at  all.  In  fact, 
it  is  doubtful  if  a  negative  report  should  ever 
be  given. 

Cases  will  sometimes  occur  in  which  it  is 
exceedingly  difficult  to  distinguish  between  a 
small  area  of  sclerosed  bone  and  a  root — the 
writer  has  had  several.  It  is,  therefore,  neces- 
sary to  regard  (1)  position,  (2)  shape,  (3) 
structure,  (4)  density.  Indeed,  it  is  possible 
for  the  alveolus  and  root  to  become  equally 
dense  and  in  such  a  case  differentiation  in 
structure  is  not  to  be  seen,  and  the  root  is  oidy 
shown  by  the  dark  line  of  periodontal  membrane. 

(7)  Supernumerary  and  Supplemental  Teeth. 
^It  occasionally  happens  that  a  swelling  about 
the  jaws  is  found,  on  radiographing  the  part,  to 
be  due  to  one  of  these  teeth.  They  may  also 
be    an    unsuspected    source    of    difficulty    in 


The  writer  has  frequently  expressed  the 
opinion  that  for  small  objects — such  as  buried 
roots — radiographs  taken  on  films  in  the  mouth 
form  the  best  means  of  discovering  them.  In 
youth  a  buried  root  (owing  to  the  different 
degree  of  calcification  of  the  tissues)  will  appear 
more  distinctly  than  in  an  adult ;  and  in  the 
latter  than  in  old  age.     In  the  last  period  they 


A  i; 

Fig.  948.— Film  Kadiographs  of  Maxilla  showing  a  method  of 
localizing  position  of  tooth  or  root  in  edentulous  cases. 

A.  Radiograph  shows  presence  of  a  buried  tooth. 

B.  Radiograph  with  a  wax  plate  and  irregular  twisted  fuse- 
wire  taken  in  situ. 

When  the  wax  plate  is  placed  in  the  mouth  the  position  and 
direction  of  the  tooth  is  easily  ascertained. 

orthodontic  cases,  especially  in  the  treatment 
of  semi-rotated  upper  centrals. 

In  some  cases  a  supernumerary  tooth  may 
have  erupted,  and  to  all  appearances  be  as  good 
in  strength  and  shape  as  an  adjoining  tooth ; 
if  then,  one  or  other  is  to  be  extracted,  a 
radiograph  will  show  which  of  the  two  has  the 
longer  and  better  root.  Now  if  in  these  cases 
films  are  u.sed,  the  three-position  method  must 
be  adopted,  so  that  there  can  be  no  doubt 
whatever   as  to   the   position  of   the   stronger 


721 


tooth  ;  or  if  plates  are  used,  tlieu  the  radiograph 
must  be  taken  stereoscopically. 

Condition  of  a  Tooth  Affecting  Conservative 
Treatment 

When  filling  teeth  it  sometimes  happens  that 
there  is  a  difficulty  in  the  treatment,  owing 
to  different  causes,  of  which  some  at  least  can 
only  be  revealed  by  the  use  of  the  X-rays. 

Before  going  further  it  may  be  stated  that 
after  examining  hundreds  of  radiographs  of 
teeth  that  were  obviously  alive,  and  also  some 
that  were  knovra  to  have  dead  pulps,  the 
writer  is  of  opinion  that  it  is  not  possible  to 
decide  definitely  only  from  the  appearance  of 
the  pulp  whether  the  tooth  is  alive  or  dead. 
Tlie  pulp  is  always  to  be  seen  as  a  dark  shadow 
down  the  length  of  the  tooth,  Ijy  reason  of  the 
crown  and  root  being  tliimier  in  the  centre. 
The  density  of  the  pulp  due  to  vascularity  is  so 
very  little,  as  compared  wth  the  much  greater 
density  of  the  dentine,  that  it  becomes  practically 


teeth  this  is  an  important  point  to  have  de- 
cided, and  it  is  easily  done  by  the  X-rays. 
In  the   mechanical   movement  of  a  tooth — 


Fig.  949. — Maxillary  Lateral  lucisor  without  caries 
diagnosed  as  having  a  dead  pulp  owing  to  its 
abscess.  This  was  proved  to  be  correct  on  drilling 
into  it. 

nil.  Why,  therefore,  because  it  is  no  longer 
vascular,  should  any  difference  be  seen  between 
a  live  and  a  dead  pulp  ?  The  pulp-chamber 
may  or  may  not  be  filled  with  putrescent 
material,  vhich  \^ould  not  differ  in  density 
from  a  healthy  pulp. 

It  may  be  possiljle,  however,  to  decide  by 
other  indications  revealed  bj'  the  radiograph 
that  a  pulp  is  dead  (see  Fig.  949). 

(1)  Calcification  of  the  Pulp.  If  the  pulp 
is  calcified  there  will  be  no  appearance  of  the 
pulp-chamber  at  all  owing  to  the  density  of 
the  pulp  being  about  the  same  as  the  dentine. 

Calcified  bodies  in  the  pulp  may  be  discovered 
if  the  radiograph  is  taken  with  a  tube  of  fine 
defimtion  and  low  penetration ;  but  these 
structures,  on  account  of  their  minuteness, 
require  the  best  of  conditions  to  enable  them 
to  be  revealed.  Only  film  radiographs  are  of 
any  value  for  these  cases  (see  Fig.  950). 

(2)  Open  or  Closed  Apex. — In  treating  dead 


Fig.  ySO. — Liistal  Caries  in  tii-st  lower  molar  with 
pulp-stone  at  coronal  end  of  anterior  root. 

say  torsion  of  an  upper  central — the  question 
of  an  open  apex  is  of  vital  importance. 

In  the  case  of  teeth  in  which  the  pulps   have 


Fig.  951. 


1) 


A.  Absorption  of  Apex  of  crowned  first  upper  premolar, 

and  rarefaction  of  alveolus. 

B.  Apical  Absorption  after  replantation  of  left  upper 

central  incisor. 

C.  Abscesses  of  left  upper  central  and  lateral  incisors. 

Some  absorption  of  apex  of  left  lateral. 
1).  Dental  cyst:  left  upper  central  and  lateral  incisors 
with  apical  absorption.     Lateral  carrying  a  bridge. 

been  killed  by  either  accident  or  caries  before 
the  tooth  has  been  fully  developed,  successful 
treatment  will  depend  upon  a  knowledge  of  the 
condition  of  the  apex. 

(31  Absorption  of  Apex. — This  also  is  a  matter 
about  which  information  can  be  obtained  by 


722 


the  X-rays  in  cases  of  periodontal  disease, 
chronic  sinus,  implantation,  replantation  and 
injury  (see  Fig.  951). 

(4)  SJiape  and  Length  of  Roots  and  Canals. 
X-rays  may  be  usefully  applied  to  ascertain 
the  form  of  roots,  as  it  is  well  known  that  an 
abnormal  shape  of  a  root  may  be  the  cause  of 
the  root -canal  drill  perforating  the  side ;  or  may 
prove  to  be  tlie  cause  of  failure  in  treating  and 
filling  the  canal. 

The  exact  length  of  a  root  cannot  be  measured 
in  all  cases,  even  if  it  is  taken  with  films.  On 
account  of  the  curvature  of  the  maxilla  and  the 
direction  of  the  rays,  magnification  may  take 
place,  especially  in  mouths  wiih  shallow  flat 
vaults.  In  the  mandible,  however,  where  the 
sides  are  almost  vertical,  this  difficulty  will  not 
exist,  and,  moreover,  the  X-rays  will  be  directed 
in  a  nearly  horizontal  direction ;  consequently 
the  length  of  a  root  can  be  ascertained  with  a 
fair  amount  of  accuracy.  The  importance  of 
knowing  the  length  will  probably  be  greatest  in 
cases  of  live  rudimentary  upper  laterals,  which 
it  may  be  desired  to  crown,  either  for  the  sake 
of  appearance,  or  to  form  an  abutment  for  a 
small  bridge.  As  a  rule,  in  these  cases,  there 
are  adjoining  teeth,  and  by  measuring  the 
length  of  the  crown  of  one  of  them  with 
callipers,  and  then  measuring  the  length  of  the 
crowii  as  it  appears  in  tlie  radiograph,  a  fairly 
correct  idea  of  the  proportionate  length  of  the 
root  to  be  crowned  can  be  obtained.  Or 
again,  a  strip  of  lead  foil  of  a  known  length — 
say  J  centimetre  or  J  inch — can  be  gummed  on 
to  the  tooth,  and  the  measurement  of  this  as 
it  appears  in  the  radiograph  will  give  the 
necessary  information ;  for  if  it  has  become 
elongated — the  more  probable  error — then  the 
root  whose  length  is  required  has  become 
elongated  in  the  same  ratio. 

Should  the  tooth  be  a  premolar  or  molar, 
then  the  length  of  the  root  may  be  estimated  by 
the  amount  of  masticating  surface  shown  in 
the  radiograph.  Thus,  if  the  ivhole  of  the 
masticating  surface  is  to  be  seen,  then  little  or 
no  root  is  showTi,  owing  to  the  X-rays  having 
been  directed  vertically,  or  (perhaps  more 
accurately)  in  the  direction  of  the  length  of  the 
root ;  this  erior  is  usually  found  in  film  radio- 
graphs of  the  maxilla.  But  if,  on  the  other 
hand,  little  or  no  masticating  surface  is  seen, 
then  the  rays  have  been  directed  at  right  angles 
to  the  length  of  the  tooth,  and  the  nearest 
possible  approach  to  the  exact  length  of  the 
tooth  or  root  is  shown,  provided  also  that 
the  film  was  at  right  angles  to  the  direction 
of  the  rays.  Hence,  of  the  two  jaws,  the  length 
of  lower  roots  is  the  more  easy  to  obtain,  and 
that  of  upper  roots  ^^■ith  a  flat  palate  the  more 
difficult. 

(5)  Exostosis. — Until   the   advent   of   X-rays 


it  was  impossible  to  diagnose  this  condition  of 
root  with  absolute  certainty.  It  can  now  be 
observed  not  only  in  film  negatives,  but  also 
in  plates,  flat  or  stereoscopic. 

(6)  Number  of  Roots. — An  unsuspected  addi- 
tional root  wiU  sometimes  give  a  great  deal  of 
trouble  in  the  treatment  of  a  tooth,  and  although 
after  opening  up  the  pulp-chamber  the  extra 
canal  may  be  noticed,  yet  its  presence  may  some- 
times be  overlooked. 

(7)  Unsuspected  Caries. — It  would  probably 
never  be  supposed,  with  all  the  modern  means 
of  examining  any  part  of  the  mouth,  that  X-rays 
would  be  of  service  in  this  particular.  But, 
unfortunately,  it  is  not  uncommon  for  cavities 
to  be  missed  in  the  ordinary  way,  especially 
in  the  apjjroximo -cervical  area,  a  region  that 
is  admittedly  difficult  to  examine  perfectly 
without  separation ;  and  when  it  is  not  possible 
or  is  in  any  way  inadvisable  to  wedge  the  teeth 
apart  satisfactorily,  the  X-rays  should  be  used ; 
it  will  be  found  a  much  easier  method  for  the 
patient,    quicker,    and    more    comfortable.     In 


Fig.  952. 

a  case  of  trismus,  caries  was  found  on  the 
affected  side  below  a  large  filling. 

A  case  that  is  probably  unique  was  that  of  a 
young  lady  who  was  sent  to  the  wTiter  to  be 
X-rayed  for  suspected  impacted  third  molar. 
She  complained  of  pain  in  the  region  of  the 
first  mandibular  molar,  \\hich  was  firm,  and 
of  good  colour,  and  liad  not  "  a  speck  of  caries 
about  it".  The  X-rays  showed  that  there 
was  no  impacted  molar ;  but  the  film  negatives 
showed  a  somewhat  dark  shadow  in  the  first 
molar  on  the  distal  aspect,  extending  from  the 
disto-cervical  margin  to  fully  a  third  of  the 
masticating  surface.  In  addition,  the  pulp  was 
asymmetrical,  the  distal  cornua  of  the  pulp 
having  disappeared  (see  Fig.  952). 

The  writer  considered  that  the  pulp  could 
not  liave  assumed  such  a  shape,  unless  it  was 
protecting  itself  by  the  formation  of  secondary 
dentine  due  to  caries,  and  al.so  that  the  some- 
what dark  shadow  already  mentioned  (due  to 
tliinning  of  the  calcified  tissues)  indicated  a 
large  cavity.  The  dental  surgeon,  therefore, 
most   thoroughly  examined   the   tooth,   as   he 


723 


was  also  of  the  opinion  that  the  tooth  was 
carious,  from  the  radiographic  appearance,  but 
was  unable  to  find  even  a  "  pin's  head  "  cavity. 
The  pain,  however,  continued  for  some  weeks, 
and  all  other  possible  causes  having  been  elimin- 
ated, the  first  molar  was  opened  up  with  a  drill, 
when  a  large  cavity  was  found  with  an  ulcerated 
pulp  !  On  treatment,  the  pain,  which  had 
existed  for  several  months,  entirely  disaf)peared. 
Tliis  case  is  mentioned  at  length  to  show  tlie 
necessity,  when  interpreting  dental  radio- 
graphs, of  noting — 

(a)  The  dark  area  in  crown  caries,  and 

(b)  The  shape  of  the  pulp. 

In  another  case  a  patient  was  radiographed 
for  "pain  on  left  side  of  face".  She  was 
almost  edentulous,  and  no  cause  for  the  pain 
could  be  found  on  examining  the  mouth ;  but 
the  radiograph  showed  a  distal  cavity  in  a  lower 
molar,  extending  from  the  cervical  edge  some 
distance  down  the  posterior  root, 
and  medially  as  far  as  the  anteiior 
root.  The  ^^•riter  has  not  heard  the 
cUnical  history  of  this  case,  but  it 
was  obvious  that  the  tooth  should 
be  removed  before  seeking  for  any 
other  cause  of  the  pain. 


area   of   inflammation    may  also   be   seeti   (see 
Fig.  954. 


Fig.  953. 


-Upper  Central   Incisor,  double 
fracture  of  root. 


(8)  hijury  to  Tooth. 

(a)  Fracture  of  root. 

{b)  Perforation. 

(c)   Foreign  body — broken  drill. 

pulp-extractor. 
{(I)  FUhng  forced  through  apex. 
(e)   Fracture  of  upper  central. 
(/)    Dislocation. 

(g)  Fracture  in  extraction  (see 
Fig.  953). 

(«)  When  a  tooth  has  been  injured 
by  violence,  and  fracture  of  the  root  is 
suspected,  the  X-rays  will  easily  show 
the  condition,  ])referably  by  films. 

(b)  This  accident  can  be  detected  by  a 
slight  darkness  proceeding  from  the  coronal 
end   of  the   root  to  the  cementum,   where  an 


Fin.  954.— Upper  Lateral 
Incisor,  perforation  of 
distal  side  of  root  (bristle 
showing  direction). 
Abscessed. 


Fio.  955. — Upper  Lateral 
Incisor,  drill  broken  in. 
Perforation  of  distal  side 
of  root.     Abscessed. 


(c)  Foreign    bodies,    such    as    broken    drills, 
pulp-extractors,  etc.,  are  easily  detected  in  the 


Fig.  956. 
: — "  Oxpara  ' 


forced    through    apex : 


A.  First    Upper    Premolar: 
cause  of  mucli  pain. 

B.  Upper  Premolar  ;— Filling  through  apex.     Abscessed. 

C.  Lower  Molar :— Filling  tlirough  anterior  root.     Abscessed. 

D.  Upper  Incisor  : — Filling  through  apex.     Abscessed. 

E.  Upper  Lateral  Incisor :— FiUing  through  apex.     Large  abscess. 

radiograph  bv  a  light  shadow  in  the  root  having 
the  shape  of  a  root -canal  instrument  (see 
Fig.  955). 


724 


tilling 


((/)  This  is  an  accident  in  the  operation  of 
that  can  very  easily  happen  (see  Fig. 
956  A,  B,  C,  D,  E).  Fig.  956  A  shows  an 
example  that  occurred  with  a  careful  operator ; 
solution  of  gutta-percha  has  become  forced 
through  the  apical  foramen,  and  is  keeping  up 
the  irritation.  If  this  had  been  one  of  the 
fillings  pervious  to  the  rays  that  are  sometimes 
used,  it  would  not  have  been  detected. 

(e)  It  will  occasionally  happen  that  in  these 
accidents,  ^^here  a  large  corner-piece  of  the 
tooth  is  knocked  off,  the  use  of  the  rays  becomes 
desirable  to  discover  po.ssible  injury  to  the  root, 
or  in  young  patients  to  ascertain  whether  the 
apex  remains  open. 

(/)  This  question  may  arise  in  cases  of 
accident.  A  case  occurred  where  a  boy  was 
thrown  off  his  bicycle  and  fractured  the  alveolar 
portion  of  the  pre-maxUla,  and  was  sent  to  be 
X-rayed  to  decide  whether  the  whole  tooth  was 
knocked  out,  or  %\hether  any  portion  remained 
or  had  been  forced  into  the  nose.  The  radio- 
graph showed  that  the  tooth  was  entirely 
knocked  out,  and  that  in  addition  the  alveolar 
plate  was  fractured. 

ig)  The  use  of  the  rays  here  is  most  useful ; 
it  saves  the  patient  unnecessary  probing,  and 
by  showing  the  direction  of  the  root  or  roots  is 
more  instructive.  If  possible  the  radiograph 
should  be  taken  before  any  extensive  inflamma- 
tion sets  in.  Plate  radio- 
graphs are  sometimes 
better  than  films  in  these 
caises,  on  account  of  the 
pain  that  may  be  caused 
by  holding  a  film  in  the 
mouth. 

The  writer  has  the 
radiograph  of  a  mandi- 
l)ular  third  molar,  with 
the  apical  portion  bent 
at  almost  a  right  angle 
towards  the  second  ;  the 
extraction  of  such  a 
tooth  must  be  accom- 
panied by  fracture  of  the 
apex. 
(h)  Injury  to  a  lateral  inci.sor  has  caused 
absorption  of  alveolus  (Fig.  957). 

Conditions  Involving  Difficulties  in  Extraction 

Such  conditions  may  be — 

Impacted  third  molar ; 

Additional  root ; 

Unenipted  tooth  causing  obstruction  ; 

Unusual  size  and  shape  ; 

Supernumerary  in  palate. 

Tlie  difficulty  of  extracting  an  impacted 
third  molar  may  be  simplified  by  the  use  of  the 
X-rays,  and  risk  of  injury  to  the  jaw  lessened. 


Fig.  957. — I'pper  Lateral 
Incisor.  Kesult  of  blow. 
Socket  absorbed. 


In  the  case  shown  in  Fig.  958  it  was  found 
impossible  to  remove  the  third  molar,  but  this 
was  effected  without  undue  injury  to  the 
surrounding  parts  after  a  radiograj)h  had  been 
obtained.  The  mandible  was  very  shallow  and 
weak. 

It  not  infrequently  happens  that  in  taking 
radiographs  for  other  purposes,  an  unsuspected 
third  molar  is  found. 

Another  condition  in  which  the  X-rays  are 
most  useful  to  the  dental  surgeon  is  that  of 


Fig.  95S.  — Case  uf  difficult  extraction  of  Third  Mandi- 
bular Molar.  Mandible  is  unusually  shallow  and 
haa  a  large  inferior  alveolar  canal. 

a  supernumerary  tooth  in  the  palate,  or  other 
teeth  much  misplaced,  e.  g.  a  premolar  or 
canine  luider  the  tongue,  etc.  Possibly  only 
a  point  of  the  tooth  can  be  seen  or  felt  with  a 
probe,  which  does  not  reveal  the  direction  and 
length  of  the  root — ob\'iously  a  most  important 
particular.  In  fact,  it  might  be  legally  argued 
in  such  cases  of  obvious  difficulty,  that  if  a 
dental  surgeon  failed  to  avail  himself  of  the 
X-rays  before  attempting  extraction,  blame 
might  be  attached  to  him  for  unfortunate 
results  caused  by  conditions  that  the  X-rays 
would  have  revealed. 

Additional  roots,  obstruction  by  an  unerupted 
tooth,  unusual  size  and  shape  of  roots,  etc., 
are  other  causes  that  can  be  revealed. 

Films  or  plates  must  be  chosen  according  to 
position  and  other  circumstances. 

Periodontal  Disease 

All  authorities  on  the  study  of  disease  involv- 
ing the  peridontal  membrane,  are  agreed  upon 
the  value  of  X-rays  as  a  means  of  ascertaining 
the  exact  condition  of  the  ti-ssues.  But  opinion 
as  to  the  best  means  of  attaining  this  end 
differs    considerably.      The    majority    in    this 


725 


country,  on  the  Continent,  and  in  America, 
prefer  films,  while  others  prefer  plate  negatives 
taken  stereoscopically.  If  films  are  used  then 
each  region  of  the  maxilla  and  mandible  must 
be  taken  separately,  not  less  than  five  films 
being  necessary  for  each  ja«- — one  each  for  the 
premolar  and  molar  region  on  each  side,  one 
each  for  the  canine  regions,  and  one  for  the 
incisor  region. 

Films. — Tliese,  taken  in  the  moutli  and  re- 
tained either  by  the  patient's  fingers  or  by  the 
film  holder  (previously  mentioned)  are,  in  the 
opinion  of  the  WTiter,  the  best  method  for 
ascertaining  the  extent  of  tliis  disease.  It  is 
possible  to  obtain  with  films  much  finer  detail 
than  if  the  radiographs  are  taken  ^^■ith  large 
plates  (externally).  They  can  show  the  gingival 
margin,  tlms  giving  the  depth  of  the  pockets ; 
the  line  of  the  alveolus,  showmg  the  extent  of 
absorption  ;  the  condition  of  the  ai^ex  ;  thickened 
periodontal  membrane,  or  any  part  of  the  root 
that  is  denuded  of  it ;  the  presence  of  the  small 
((uantity  of  black  tartar  so  frequently  found 
accompanying  this  disease,  either  in  a  ring  or 
in  nodules ;  and  also  the  extent  of  rarefaction 
in  alveolus  (osteo-porosis),  usually  most  notice- 
able between  the  teeth.  Fuse-wire  tied  round 
the  necks  of  the  teeth,  or  lead  foil  gummed  on. 
may  be  used  to  indicate  the  original  line  of 
attachment  of  the  gums. 

As  the  rays  have  only  to  pass  through  one 
side  of  the  face  (and  the  film  is  close  to  the  teeth), 
they  do  not  require  to  be  so  powerful  as  for 
plate  work,  and  thus  it  is  unlikely  that  any 
particular  structure  will  be  ov^er-ijenetrated  or 
entirely  prevented  from  being  recorded  on  the 
negative. 

Film  negatives,  being  flat  radiographs,  \\\\\ 
not  show  conclusively  on  which  side  of  a  tooth — 
say  a  molar — the  absorption  is  greater,  although 
the  negative  may  show  two  lines  of  alveolus. 
Stereoscopic  radiographs  on  films  can  be  taken, 
but  owing  to  the  smallness  of  the  negatives 
and,  consequently,  the  absence  of  a  sufficient 
number  of  objects,  the  result  is  of  so  little 
value  as  not  to  lie  worth  tlie  extra  tro\ible 
necessary. 

If  radiographs  are  taken  at  the  beginning  and 
during  the  treatment  of  cases,  the  changes  can 
be  watched,  and  an  invaluable  record  obtained. 
P/aYes.— Plate  negatives  taken  externally 
nuist  be  taken  stereoscopically,  negatives  in 
the  flat  being  of  little  use  unless  the  disease  is 
affecting  only  one  side  of  the  jaw  or  jaws.  But 
even  if  the  disease  is  local,  if  a  flat  negative  is 
of  value  then  it  is  a  certain  fact  that  a  stereo- 
scopic view  would  be  infinitely  better. 

As  is  well  known,  the  disease  more  often 
than  not  commences,  or  if  of  long  stantling  is 
usually  more  advanced,  in  the  lower  incisor 
region — a  position  that  cannot  be  satisfactorily 


included  in  a  s(ereoscoj)ic  plate  negative,  if 
taken  at  the  side  of  the  face  for  the  other 
parts  of  the  mouth.  If  it  is  desired  that  this 
region  should  be  taken  stereoscopically  then 
it  should  be  taken  with  the  plates  in  front 
of  the  patient,  and  the  X-raj-s  directed  postero- 
anteriorly  from  below  the  occiput,  and  suffici- 
ently upward  to  include  the  nasal  fossae. 

There  are,  however,  objections  to  this ; 
fii-stly,  the  cervical  vertebrae  wUl  be  seen  and 
somewhat  mar  the  part  to  be  investigated ; 
and  secondly,  owing  to  variation  in  the  degree 
of  curvature  of  the  jaw  or  jaws,  the  number  of 
teeth  distinctly  shown  in  the  radiograph  will 
also  vary;  that  is  to  say,  in  a  narrow  or  con- 
tracted arch  possibly  only  the  central  incisors 
are  to  be  seen,  while,  on  the  other  hand,  in  a  broad 
arch  all  four  incisors  may  be  seen,  with  more 
or  less  of  the  canines.  To  prevent  the  cervical 
vertebrae  interfering  with  the  clearness  of  the 
incisor  region,  the  X-ray  tube  may  be  brought 
up  to  a  few  inches  from  the  patient ;  by  this 
means    the    vertebrae   will    become    so    much 


Fig.    959.  —  Kadiograph    of    I'pper    Lateral    Incisor. 
Shows  normal  condition. 

penetrated  as  to  be  practically  invisible.  But 
when  the  tube  is  so  close  to  the  patient  the 
stereoscopic  view  is  not  quite  so  good ;  it  nmst, 
however,  be  admitted  that  this  is  not  usually 
so  important  for  the  incisor  region  as  for  the 
back  of  the  mouth.  For  these  reasons,  it  is 
usual  to  take  the  incisor  region  with  films ;  or 
the  rays  may  be  directed  between  the  cer\-ical 
vertebrae  and  the  ascending  ramus  on  either 
side  or  on  both  sides,  the  latter  generally  being 
necessary,  and  making  altogether  three  pairs 
of  stereoscopic  radiographs. 

It  may,  perhaps,  be  as  well  here  to  consider 
the  appearance  of  the  normal  tissues  before 
describing  abnormalitie:?. 

The  enamel  of  the  tooth  appears  as  a  light 
shadow ;  the  dentine  and  cementum  not  quite 
so  light  as  enamel ;  and  the  pulp  cavity  much 
darker  than  the  dentine  and  cementum. 

Between  the  socket  and  the  root  a  fine  dark 
line  is  seen  ref)resonting  the  ijeiiodontal  mem- 
brane, while  external  to  tliis  is  a  fine  white  line 
representing  the  thin  compact  l)one  of  the  socket. 
This    line    is    easily    seen    l)('tween    the    lower 


726 


incisors,  running  up  to  a  point  at  the  cervical 
edge ;  the  alveohis  between,  being  cancellated, 
exhibits  a  porous  appearance,  and  a  darker 
shadow  than  tlie  other  tissues.  Between  the 
molars  the  alveolus  does  not  run  up  into  a  point, 
but  forms  a  flat  surface  almost  square  with. 
the  teeth  (see  Fig.  959). 

The  radiographic  appearance  of  teeth  and 
the  surrounding  tissues  when  affected  by  peri- 
odontal disease  is  as  follows  (see  Figs.  960,  961, 
962). 

The  gingival  margin  \vill  appear  as  a  slight 
opacity  between  the  teeth  transversely  near 
the  cervical  margins.     The  alveolus  wall  be  seen 


If  an  abscess  is  present  a  dark  space  with  well- 
defhied  edges  is  to  be  seen,  or  an  iU-defuied 
dark  area  at  the  apex,  indicating  suppurative 
osteitis. 


Fid.  960.— Shows  First  Premolar  badly  affected  with 
periodontal  disease.  The  other  teeth  are  also 
affected,  the  first  molar  having  absorption  above 
the  bifurcation,  and  also  caries  on  the  distal  side. 

as  a  more  porous  structure  reaching  up  the 
root  a  greater  or  less  distance  according  to  the 
amount  of  absorption,  and  having  a  rough, 
uneven  surface.  The  gingival  margin  and 
alveolar  line  give  the  depth  of  the  pocket. 

Rarefaction,  or  osteo-porosis,  is  best  seen 
between  the  roots  of  teeth,  as  irregularly  shaped 
dark  spots,  usually  noticed  midway  between 
the  roots  of  the  teeth  in  the  incisor  region  of 
the  mandible. 

The  apex  of  the  roots  may  appear  blunted 
or  shortened,  and  shaped  irregularly,  indicating 
absorption.  It  may  seem  as  if  the  apex  had 
been  excised,  or  the  root  shortened  and  reduced 
peripherally,  leaving  a  sharp  point  in  the  centre. 


Fig.  9(51. — Much  Absorption  :  I'aref action  is  well 
marked. 


The  j)eriodontal  membrane  appears  to  be 
thickened  entirely  or  in  part,  and  is  seen  as 
a  dark  line. 

The  pulp-chamber  and  root-canals  vary  in 
appearance,   but   are   usually   seen   as  a   faint 


Fig.  962. — Extensive  Absorption  in  mandibular  incisor 
region. 

shadow  down  the  length  of  the  tooth,  that  is 
to  say,  less  dark  than  in  a  healthy  live  tooth, 
on  account  of  degeneration. 

(Above    description    is    of    appearance     in 
negatives,  not  prints.) 

C.  A.  C. 


CHAPTER   XLVIII 


REFLEX   AFFECTIONS  DUE   TO   DISEASED   TEETH 


The  possibility  of  diseases  of  other  parts 
being  caused  or  influenced  by  reflex  irritation 
arising  from  dental  lesions  has  long  been  recog- 
nized. Thus  Giovanni  d'Arcoli,  in  the  fifteenth 
century,  wrote  that  "  such  very  violent  pains 
(i.  c.  dental)  are  sometimes  follo\\ed  by  syncope 
or  epilepsy,  through  injury  communicated  to 
the  heart  or  brain  "  ;  and  Ryff,  of  Strasburg, 
writing  a  century  later,  says:  "The  eyes  and 
teeth  have  an  extraordinary  aftinity  or  reciprocal 
relation  to  one  another,  by  which  they  very 
easily  communicate  to  each  other  their  defects 
and  diseases." 

Undoubtedly,  ho\\ever,  many  pathological 
conditions  recorded  then  and  since  as  being 
due  to  reflex  dental  irritation  would  not  now 
be  so  classed.  In  the  first  place,  many  cases 
were  undoubtedly  due  to  direct  extension  of 
infection  from  the  mouth  or  teeth,  but  the  tract 
of  the  infection  was  not  recognized.  In  the 
second  place,  the  diagnosis  of  "reflex  irritation  " 
was  often  adopted  to  explain  symptoms  for 
which  no  other  adequate  cause  could  be  found ; 
\\  ith  a  more  extended  knowledge  of  the  special 
pathology  of  the  several  regions  concerned,  these 
would  now  be  otherwise  explained. 

Nevertheless  there  remains  a  large  number  of 
affections  of  nerves,  muscles,  glands,  and  skin, 
of  which  the  direct  exciting  cause  may  be  traced 
to  reflex  irritations  arising  in  or  around  the 
teeth. 


Physiological  and  Anatomical  Considerations 

It  is  necessary,  for  the  proper  comprehension 
of  the  various  reflex  affections  that  will  be 
described,  that  not  only  the  physiology  of 
reflex  action  in  general,  but  also  the  special 
physiological  and  anatomical  relationships  of 
the  trigeminal  nerve  to  other  nerves  should  be 
well  understood.  For  a  detailed  consideration 
of  these  subjects  the  reader  is  referred  to  works 
on  physiology  and  anatomy ;  it  will,  however, 
be  useful  here  to  point  out  the  more  salient 
facts. 

(a)  General. — A  reflex  is  essentially  the  con- 
version of  an  afferent  into  an  efferent  impulse. 
This  reflection  may  be  effected  by  certain  cells 
in  the  spinal  cord  or  brain,  or,  in  the  case  of 
the  sympathetic  nerves,  by  cells  in  peripheral 
ganglia. 


(6)  Special.  —  The  sensory  fibres  of  the  tri- 
geminal nerve  arise  from  the  cells  in  the  semi- 
lunar ganglion ;  they  bifurcate,  and  one  branch 
passes  out  of  the  skull  to  the  skin,  mucous 
membrane,  and  teeth,  whilst  the  other  passes 
backwards  to  the  pons  and  arborizes  around 
the  sensory  nucleus  of  the  trigeminal  nerve  in 
the  medulla.  The  latter  branch  also  bifurcates, 
some  fibres  being  contiinied  down  the  medulla 
oblongata  and  into  the  spinal  medulla  as  low  as 
the  second  cervical  nerve,  and  others  ascending 
as  high  as  the  upper  part  of  the  corpora  quadri- 
gemina.  These  fibres,  during  their  course,  are 
brought  into  anatomical  relationship  with  the 
luiclei  of  many  of  the  other  cerebral  nerves. 
The  extremely  low  point  to  which  the  descending 
root  reaches  should  be  borne  in  mind,  as  this 
may  serve  to  explain  the  connection  between 
diseased  teeth  and  reflex  affections  of  muscles 
of  the  neck. 

Furthermore,  Gaskell  (16)  has  shown  that 
apart  from  the  olfactory,  optic,  and  acoustic 
nerves  all  the  cerebral  nerves  are  development- 
ally  connected  with  the  sensory  root  of  the 
trigeminal  nerve. 

The  structure  of  the  medulla  oblongata  shows 
that  the  sensory  portions  (posterior  root)  of  the 
glosso-pharyngeal,  vagus,  accessory,  and  hypo- 
glossal nerves  (excluding  the  visceral  branches) 
are  absent  from  the  nerves  themselves,  but  that 
they  have  become  diverted  to  help  to  form  the 
sensory  part  of  the  trigeminal  and  the  semilunar 
ganglion.  With  regard  to  the  remaining  nerves, 
i.  e.  the  oculo-motor,  pathetic,  trigeminal  (motor 
division),  abductnt,  and  facial,  it  was  shown  that 
their  sensory  nuclei  have  degenerated,  although 
their  anatomical  outlines  still  remain,  and  that 
they  are  now  functionally  represented  l)y  the 
sensory  root  of  the  trigeminal. 

In  fact,  Gaskell  demonstrated  that  the 
majority  of  the  cerebral  nerves  are  exactly 
analogous  to  spinal  nerves,  with  an  anterior 
or  motor  root  and  a  posterior  or  sensory  root, 
but  that  whilst  the  motor  roots  have  remained 
separate  the  sensory  roots  have  all  become 
merged  into  the  sensory  division  of  the  tri- 
geminal nerve. 

Under  these  conditions  it  would,  a  'priori,  be 
expected  that  stimulation  of  the  terminal 
branches  of  the  trigenunal  nerve  would  give 
rise  to  very  vaiied  and  numerous  reflexes.    This, 


727 


728 


in  fact,  is  found  to  be  so,  and  for  the  sake  of 
convenience  the  reflex  effects  may  be  classified 
in  the  following  ways — 

■  Motor  or  volitional  cerebral 
areas. 
Motor  nerves:    (1)  Tonic; 

(2)  Clonic. 
Vaso-motor  nerves. 
Secretory  nerves. 
,  Nerves  of  special  sense. 

C  Motor  nerves. 

1  Trophic  nerves. 

'-  Nerves  of  special  sense. 


Stinnilation  of 


Inhibition    of 


Affections  arising  from  Stimulation  of  a  whole  or 
a  part  of  the  Motor  or  Volitional  Areas  of  the 
Brain 

In  these  conditions  certain  cortical  areas  of 
the  brain  are  probably  in  a  state  of  abnormal 
excitability,  and  the  stimulation  of  the  tri- 
geminal nerve  merely  acts  as  the  spark  that 
gives  rise  to  the  explosion  of  energy,  or,  in 
electrical  phraseology,  represents  tlie  weak 
primary  current  that,  acting  on  a  "  relay  ",  calls 
into  being  a  very  powerful  secondary  current. 

Such  explosion  or  exhibition  of  energy  in  an 
abnormal  form  may  be  manifested  as  epilepsy, 
chorea,  hysteria,  a  transient  form  of  insanity, 
or  insomnia. 

Epilepsy. — So  many  cases  of  epilepsy  having 
a  demonstrably  causal  connection  with  diseased 
teeth  have  been  recorded  both  by  phj'sicians 
and  dental  surgeons,  that  there  can  be  no  doubt 
that  irritation  of  the  dental  branches  of  the  tri- 
geminal nerve  (in  common  with  other  sources  of 
peripheral  irritation)  is  to  be  regarded  as  a 
frequent  exciting  cause  both  of  liwut  mal  and 
petit  mal  in  those  patients  whose  cerebral  centres 
are  in  a  state  of  unstable  equilibrium. 

A  condition  of  epileptiform  convulsions  has 
been  experimentally  produced  by  Brown  Sequard 
by  ^^eak  stinndation  of  the  trigeminal  nerve 
after  section  of  a  lateral  colunni  of  the  spinal 
cord  in  the  cervical  or  dorsal  region. 

A  very  interesting  case  came  under  the 
observation  of  the  writer  in  1905. 

A  girl,  aged  1 1  years,  had  suffered  from  attacks 
of  epilepsy  for  some  time,and  was  being  medically 
treated  by  Sir  James  Sawyer.  The  attacks  dis- 
appeared after  an  exposed  pulp  in  a  lower  molar 
had  been  treated,  and  did  not  recur  for  twelve 
months.  It  \\a,s,  then  found  that  an  exposure 
had  occurred  in  another  lower  molar ;  this  was 
treated,  and  the  attacks  again  subsided,  and  as 
far  as  is  known  did  not  recur. 

Tomes  (55,  p.  695)  records  a  case  of  epilepsy 
in  a  boy,  in  whom  the  fits  occurred  two  or  three 
times  a  day,  and  the  ordinary  medical  remedies 
were  used  ^^ithout  avail  for  six  weeks.     The 


extraction  of  some  septic  (presumably)  lower 
molars  was  at  once  followed  by  a  cessation  of 
the  seizures.  Tliere  had  been  no  recurrence 
in  eighteen  months'  time. 

A  case  of  petit  mal  (transient  loss  of  conscious- 
ness) occurring  in  a  patient  whenever  he  under- 
went dental  treatment  is  recorded  by  Morton 
Smale  (53,  p.  761). 

Many  other  cases  of  epilepsy  due  to  disease 
of  the  teeth  are  recorded  by  Tomes  (55,  p.  695), 
Ramskill  (44),  Portal  (37),  Coleman  (6),  West 
(62),  Brubaker  (4)  (eighteen  cases),  Putnam 
(43),  and  others.  It  should,  however,  be  noted 
that  Osier  is  of  opinion  that  "  genuine  cases  of 
reflex  epilepsy  are  rare  ". 

Chorea. — Cases  of  chorea  of  apparently  dental 
origin  have  been  recorded,  but  in  view  of  the 
fact  that  chorea  is  now  largely  regarded  as 
resulting  from  an  infection,  it  is  probable  that 
cases  so  described  have  been  a  form  of  convulsive 
tic  rather  than  true  acute,  or  Sydenham's  chorea. 
Nevertheless  many  medical  authorities  are  of 
opinion  that  all  possible  sources  of  irritation 
of  the  trigeminal  nerve  should  be  eliminated  in 
the  treatment  of  true  chorea. 

A  case  where  choreic  movements  were 
associated  with  diseased  teeth  is  recorded  by 
Pierce  (36). 

"  A  boy,  aged  9  years,  had  always  been  in  good 
health  until  two  years  ago,  when  he  was  attacked 
with  choreic  movements,  chiefly  in  the  muscles 
of  the  face,  though  present  also  in  the  muscles 
of  the  neck  and  shoulders.  Owing  to  their  local 
character,  and  the  absence  of  the  causes  usually 
assigned  for  the  appearance  of  chorea,  it  was 
thought  possible  that  the  condition  of  the  teeth 
might  offer  some  explanation  of  the  trouble. 

"  Careful  examination  of  the  mouth  revealed, 
in  addition  to  considerable  overcrowding  of  the 
teeth,  persistence  of  the  deciduous  incisors. 
After  their  removal  the  choreic  movements 
at  once  subsided.  A  year  later  there  was  a 
return  of  the  symjDtoms.  Examination  of  the 
teeth  again  showed  a  persistence  of  the  deci- 
duous molars  delaying  the  eruption  of  the  pre- 
molars. Removal  of  the  offending  teeth  was 
followed  by  complete  recovery." 

Hysteria. — In  persons  with  neuropathic  ten- 
dencies it  is  quite  possible  that  an  attack  of 
odontalgia  may  be  sufficient  to  upset  the  normal 
correlation  of  control  between  muid  and  body, 
and  thus  induce  symptoms  of  hysteria. 

It  should  be  remembered,  though,  that  hysteria 
is  manifested  in  a  large  variety  of  ways,  and 
many,  if  not  all  of  the  conditions  described  in 
this  section  as  being  possibly  due  to  reflex 
irritation  from  diseased  teeth,  may  be  symptoms 
of  hysteria  that  has  not  of  necessity  originated 
from  the  teeth. 

Many  cases  have  been  recorded  by  reliable 


729 


authorities,  Init  the  certain  demonstration  of 
cause  and  effect  in  these  conditions  is  not  by 
any  means  easy  or  clear.  The  converse  is  more 
certain,  i.  e.  that  odontalgia  is  occasionally  a 
manifestation  of  hysteria. 

Insanity. — In  vie\\-  of  the  fact  that  stimuli  ' 
arising  from  diseased  teeth  are  capable  of  being 
reflected,  or  of  "  spreading  "  to  the  motor  and 
sensory  areas  of  the  brain,  as  in  epilepsy  and 
neuralgia,  ancl  to  the  volitional  centres,  as  in 
hysteria,  it  would  seem  to  be  neither  impossible 
nor  improbable  that  such  stimuli  should  be 
reflected  in  a  similar  manner  to  the  higher 
centres  of  the  brain  controlling  the  conscious 
reasoning  powers,  and  be  suiiicient,  occasionally, 
to  disturb  the  "  balance  "  of  the  mental  facul- 
ties. Twelve  cases  of  such  a  nature  are  recorded 
by  Upson  (57).  The  majority  of  these  were 
cases  of  dementia  praecox,  and  were  all  associ-  ' 
ated  with  either  diseased,  impacted,  or  faultily 
treated  teeth.  They  were  all  treated  by  ex- 
traction of  the  affected  teeth  after  radiographs 
had  been  taken,  by  means  of  which  various 
unsuspected  dental  lesions  were  brought  to 
light.  Ten  of  the  cases  benefited  con.siderably, 
and  were  apparently  cured  by  the  treatment ; 
in  the  remaining  two  no  improvement  followed. 
In  none  of  the  cases  did  the  patient  complain 
of  odontalgia. 

The  writer  was  recently  consulted  in  a  case 
in  which  the  patient,  a  female  aged  20,  had 
been  subject  for  two  years  to  attacks  of  dementia. 
The  patient  looked  and  was  in  perfect  health, 
and  led  an  active  outdoor  life.  The  teeth  that 
were  present  (a  few  had  been  extracted)  were 
perfectly  sound,  but  the  four  third  molars  were 
all  in  the  pre-eruption  stage,  and  the  bite  being 
"close"  there  was  no  possible  room  for  their 
eruption. 

In  the  absence  of  anj^  other  discoverable  cause 
by  capable  experts,  and  in  view  of  the  fact  that 
the  teeth  gave  rise  to  no  local  pain,  the  writer 
was  very  strongly  of  opinion  that  exacerba- 
tions of  the  eruptive  force  were  responsible 
for  the  disturbance  of  the  mental  equilibrium. 
Unfortunately  the  patient  refused  operative 
treatment,  and  so  the  case  is  inconclusive. 

Melancholia.— Cases  of  this  form  of  insanity  ; 
being  excited  reflexly  by  dental  lesions  are  cited  j 
by  Lodge  (31)  and  Van  Doom  (58).  The  former 
gives  the  following  instance  :  "  The  patient, 
a  young  woman,  had  been  afflicted  for  more 
than  a  year  with  profound  melancholia  ;  there 
was  terrible  depression,  delusions  of  having 
committed  many  deadly  sins,  and  tendency 
towards  suicide.  Medical  treatment  had  been 
of  no  avail.  Her  teeth  were  on  the  whole  in 
better  condition  than  those  of  the  average 
patient.  An  X-ray  examination  showed  a 
third  left  upper  molar  to  be  violently  impacted 
against    the    second    molar.     Extraction    was 


followed  in  a  few  weeks  by  a  cure.     This  case 
was  notable  by  the  absence  of  pain." 

Insomnia. — Definite  cases  of  insomnia  being 
related  to  abnormal  and  pathological  conditions 
of  the  teeth  have  lieen  recorded  by  Van  Doom 
(loc.  cit.)  and  by  Kenyon  (26).  The  former,  in 
quoting  one  case,  says  that  "  Tlie  patient  had 
not  had  a  whole  night's  sleep  for  over  a 
year,  which  only  opiates  relieved.  Radiographs 
showed  '  apical  absorption  '  around  six  teeth 
otherwise  normal.  The  teeth  were  paiidess, 
and  responded  neither  to  percussion,  heat,  nor 
cold.  Appropriate  root  treatment  was  carried 
out,  the  insomnia  disappeared  completely,  and 
had  not  returned  in  three  years'  time." 

Aflections  arising  from  Stimulation  of  Motor 
Nerves 

(1)  Tonic  Spasms  (Continuous  Contractions) 

Trismus,  or  Spasmodic  Closure  of  the  Jaws. 
Inability  to  open  the  mouth  may  arise  in  acute 
cases  from  three  different  causes.  First,  it  may 
be  the  well-known  early  symptom  of  infection 
with  the  tetanus  bacillus  in  any  part  of  the 
body,  and  of  course  such  infection  may  take 
place  in  the  mouth  through  the  presence  of 
diseased  teeth.  GUI  has  recorded  such  a  case 
(17)  in  which  the  patient  died  from  tetanus, 
presumably  from  infection  occurring  in  or 
aiound  diseased  teeth.  In  these  instances 
the  spasm  of  the  masticatory  muscles  is  due  to 
stimulation  of  the  motor  root  of  the  trigeminal 
nerve,  but  the  whole  process  can  hardly  be 
classified  as  reflex.     (See  Chapter  XLIX.) 

Secondly,  the  muscles  closing  the  jaw  may 
become  infiltrated  with  inflammatory  exudation 
arising  from  diseased  teeth,  which  may  he  so 
great  as  wholly  or  partly  to  prevent  the  mouth 
being  opened.  Instances  of  this  are  quite 
common,  and  are  usually,  though  not  correctly, 
termed  "  trismus  "'.     (See  Chapter  II.) 

The  third  cause  of  more  or  less  sudden  in- 
ability to  open  the  mouth  is  a  reflex  stimulation 
of  the  motor  branch  of  the  trigeminal  nerve, 
arising  from  irritation  of  diseased  teeth.  The 
sensory  nerve  involved  is  usually  the  third 
division  of  the  trigeminal,  and  the  second  or 
third  molar  is  usually  the  seat  of  the  lesion. 
These  are  true  cases  of  trismus.  Details  of  such 
cases  are  related  by  Salter  (48),  Tomes  (55, 
p.  697),  and  Ewart  ("12).     (See  Chapter  XLIX.) 

Inability  to  Close  the  Mouth- — due  to  spasm  of 
the  muscles  depressing  the  mandible — the  exact 
opposite  of  true  trismus.  An  interesting  case 
of  this  nature  is  recorded  by  Tomes  (55,  p.  698)  : 
"  The  patient  was  suffering .  from  difficult 
eruption  of  a  third  molar,  with  much  swelHng 
and  ulceration  of  the  adjacent  gums ;  whenever 
in  closure  of  the  mouth  the  third  upper  molar 
touched  these  inflamed  tissues,  the  mouth  was 


730 


violently  dragged  open.  This  spasm  was  of  so 
painful  a  nature  that  the  patient  went  about 
with  a  cork  between  his  teeth  so  as  to  prevent 
any  contact,  and  in  this  way  he  could  obtain 
sleep,  which  was  otherwise  impossible." 

Lagophthalmos  (Inahility  to  Close  the  Eyelids). 
This  condition  may  be  brought  about  by  spasm 
either  of  the  levator  palpebrae  or  of  Miiller's 
muscle.  In  the  former  case  the  stimulus  affects 
the  oculo-motor  nerve,  and  in  the  latter  the 
sympathetic.  Wiere  the  lagophthalmos  is  due 
to  reflex  irritation  arising  from  diseased  teeth, 
and  if  no  other  ocular  spasms  are  present,  the 
sympathetic  nerve  is  the  one  probably  involved, 
as  in  the  case  recorded  by  S.  J.  Hutchinson  (24). 
In  this  case  the  condition  had  existed  for  more 
than  a  year.  After  other  treatment  had  been 
tried,  an  exposed  pulp  was  found  under  an 
amalgam  filling  in  a  first  upper  molar ;  this  was 
treated  by  extraction  of  the  tooth.  Tlae  spasm 
at  once  began  to  improve,  and  ceased  within  six 
months  of  the  extraction. 

Inability  to  close  the  eyeUds  may  also  be  due 
to  paresis  of  the  orbicularis  palpebrarum,  which, 
in  the  opinion  of  Henry  Power,  may  be  induced 
by  reflex  dental  irritation ;  but  Sir  William 
Collins  and  others  strongly  dissent  from  this 
on  account  of  the  "  impossibiUty  of  conceiving 
of  a  reflex  paralysis  ". 

Ocular  Spasms  {Sqviyits). — On  theoretical  con- 
siderations alone,  since  the  trigeminal  nerve 
represents  the  sensory  root  of  the  oculo-motor, 
pathetic,  and  abducent  nerves,  it  might  be  ex- 
pected that  reflex  spasms  of  the  ocular  muscles 
would  be  fairly  common — at  least  as  common 
as  those  arising  from  reflex  stimulation  of  the 
facial  nerve.  Yet  this  in  actual  fact  seems  not 
to  be  the  case ;  at  any  rate  very  few  cases  of 
spasm  of  the  muscles  of  the  orbit  that  can  be 
assigned  definitely  to  reflex  dental  irritation  are 
on  record. 

Concomitant  strabismus  is  said  to  be  "  caused 
by  "  difficult  dentition  in  weakly  children ;  but 
since  Donders  demonstrated  that  the  actual 
cause  in  at  least  three-fourths  of  these  cases  is 
hypermetropia,  reflex  irritation  has  come  to  be 
looked  upon  as  of  secondary  importance. 
Tomes  (55,  p.  699),  however,  quotes  a  case  of 
strabismus  of  three  years'  duration  in  an  adult, 
wliich  was  cured  by  the  extraction  of  some 
carious  upper  molars. 

Mydriasis  (dilatation  of  the  qntpil),  due  to 
stimulation  of  the  sympathetic  fibres  supplying 
the  radiating  muscle  of  the  iris,  may  be  produced 
roflexly  by  stimulation  from  diseased  teeth. 
Henry  Power  is  of  opinion  that  it  is  to  be 
regarded  as  a  reflex  paresis  of  the  oculo-motor 
nerve. 

Torticollis.— -Wry -neck,  or  spasm  of  tlie 
sterno-mastoid  muscle,  may  occasionally  arise 
as  a  reflex  manifestation  of  carious  teeth,  and 


may  be  either  clonic  or  tonic  in  form.  A  case 
of  tonic  spasm  is  recorded  by  Hancock  (20), 
and  one  of  clonic  spasm  by  Ormerod  (35).  In 
both  of  these  cases  the  spasm  ceased  after 
extraction  of  diseased  teeth. 

Cervical  Opisthotonos. — Retraction  of  the  head 
may,  in  the  opinion  of  some  authorities,  be  due 
to  reflex  dental  irritation.  Edmund  Cautley 
(5)  says  that  "in  a  few  cases  "  he  has  been 
"  unable  to  find  any  other  explanation  for 
simple  retraction  of  the  head  " ;  and  Robert 
Hutchison  (25)  would  seem  to  be  of  the 
opinion  that  when  such  cases  do  occur  the 
immediate  cause  is  cerebral  congestion,  which 
may  be  induced  reflexly  by  stimulation  of  the 
dental  branches  of  the  trigeminal  nerve. 

(2)  Clonic  Spasms 

Histrionic  Spasm  (Contraction  of  Facial 
Muscles). — In  this  condition  the  efferent  reflex 
path  is  via  the  facial  nerve,  and  the  whole  of 
the  facial  muscles  may  be  affected,  tliough  when 
the  spasm  arises  from  dental  refle.x  irritation 
one  side  only  of  the  face  is  usually  affected. 
If  the  orbicularis  palpebrarum  is  implicated  the 
spasm  may  become  tonic,  as  in  a  case  recorded 
by  Henry  SewUl  (52),  in  which  the  eye  could 
only  be  opened  with  great  difficulty,  but  suitable 
treatment  of  carious  teeth  in  the  upper  and 
lower  jaws  was  followed  by  a  complete  cessation 
of  the  spasm. 

Smale  and  Colyer  (53,  p.  531)  quote  a  case 
from  the  Dental  Record  in  which  the  spasms 
had  lasted  for  two  years.  No  systemic  or  local 
causes  (other  than  dental)  could  be  found  to 
account  for  the  condition.  "  The  teeth  were 
in  a  neglected  condition,  the  right  side  of  the 
mouth  in  this  respect  being  much  worse  than 
the  left.  General  treatment  had  been  tried  for 
nearly  one  year.  Local  treatment  was  then 
tried,  all  roots  and  teeth  with  septic  pulps  being 
removed,  and  the  others  filled.  The  calculus 
was  removed,  and  the  gums  treated.  The  dental 
treatment  lasted  three  \\eeks,  during  which  time 
improvement  occurred,  the  patient  eventually 
making,  as  far  as  could  be  ascertained,  a  complete 
recovery." 

Tlie  orbicularis  palpebrarum  may  be  the  only 
muscle  affected,  when  the  condition  is  termed 
blepharospasm  ;  instances  are  recorded  in  which 
this  excessive  blinking  was  clearly  traceable  to 
the  teeth,  since  it  ceased  immediately  after  dental 
treatment.  Power  and  F.  J.  Bennett  (2)  also 
record  curious  cases  in  which  the  blepharospasm 
ceased  upon  pressure  being  applied  to,  or  in  the 
region  of,  the  third  lower  molar,  yet  was  not 
cured  by  simple  local  treatment  in  that  situa- 
tion. However,  in  the  case  recorded  by  Power 
the  blinking  eventually  ceased  after  section  of 
the  inferior  alveolar  nerve.  Coutts  and  Shuttle- 
worth  (9)  are  of  opinion  that  in  the  treatment 


731 


of  all  such  cases  the  teeth,  as  a  source  of  reflex 
irritation,  should  be  eliminated. 

Rigor  is  occasionally  associated  \\itii  acute 
inflammatory  conditions  around  the  teeth,  such 
as  "impacted  wisdom",  or  acute  pyorrhoea 
alveolaris.  The  afferent  path  in  this  case  is  not 
the  trigeminal  nerve,  since  the  shock  arising 
from  toxic  absorption  is  the  active  stimulus. 
The  efferent  path  is  via  the  sympathetic  system 
(causing  vaso-constriction). 

Cough.  —  Instances  of  paroxysmal  cough 
arising  from  reflex  dental  irritation  in  children 
are  not  uncommon  during  teething,  and  cases 
are  recorded  by  Sir  Lauder  Brunton  and  J.  H. 
Mummery  (32). 

Affections  arising  through  Stimulation  of  the 
Vaso-Motor  Nerves 

Cardiac  Arhythmia  and  Palpitation.  —  That 
the  nervous  mechanism  controlling  the  heart's 
action  is  capable  of  being  affected  reflexly  is 
well  known,  but  it  is  not  often  recognized  that 
sensory  impulses  set  up  by  diseased  teeth  ma^' 
be  reflected  along  the  cardiac  nerves.  Yet  cases 
of  this  nature  have  been  recorded  by  Remak 
(46),  Lederer  (30),  Anstie  (1).  and  Sir  Douglas 
Powell  (38).  The  case  related  by  the  last 
authority  was  that  of  a  woman,  aged  36,  who 
had  experienced  considerable  pain  and  irregu- 
larity of  the  lieart  for  two  years.  The  teeth 
\\ere  extensively  carious,  but  there  was  no 
dyspepsia  and  no  organic  lesion  of  the  heart. 
A  course  of  Xauheim  baths  failed  to  reheve  the 
condition,  but  eventually  "  she  consented  to 
have  her  affected  teeth  removed  under  gas 
and  ether,  which  she  took  very  well,  and  from 
that  time  lier  cardiac  symptoms  have  entirely 
ceased."  Sir  Douglas  Powell  concludes  that 
"  the  cardiac  symptoms  .seemed  to  be  due 
chiefly  to  the  reflected  irritation  of  the  decayed 
teeth." 

Vaso-dilatation  of  the  Ocular  Vessels. — Un- 
doubtedly this  condition  is  often  brought  about 
by .  reflex  dental  irritation,  and  may  be  only 
transient  in  effect,  or  it  may  serve  to  accentuate 
any  latent  or  trivial  lesion  that  may  be  present 
in  the  e\^e.  Thus  hyperaemia  of  the  conjunctiva, 
and  oedema  of  the  lids,  may  be  caused  in  this 
way,  and  so  serve  either  to  aggravate  (or 
simulate)  an  original  inflammation. 

Both  Mummery  (32)  and  Tomes  have  recorded 
a  ease  of  orbital  cellulitis  that  was  ajiparently 
caused  reflexly  by  diseased  teeth.  The  chief 
points  in  this  somewhat  interesting  case  are 
as  follows  :  The  patient,  aged  17,  suffered  on 
three  separate  occasions  from  attacks  of  "  orbital 
cellulitis  ".  Tlie  first  two  seemed  to  be  associated 
with  the  presence  of  unerupted  molars  contained 
in  their  crypts,  and  the  third  occurred  many 
years  afterwards  and  synchronized  witli  a  non- 
suppurative   periodontitis    around    an    upper 


canine ;  extraction  of  this  tooth  was  followed 
by  a  complete  cessation  of  orbital  S3Tiiptoms. 
Seeing  that  infection  of  the  orbit  by  direct 
extension  seems  to  be  negatived,  and  in  the 
absence  of  any  proof  that  the  "'  ceUuUtis  "  was 
infective  in  origin,  it  is  probable  that  this  case 
is  to  be  regarded  as  an  instance  of  reflex  vaso- 
motor disturbance  of  the  orbital  vessels,  causing 
intense  engorgement  of  the  tissues  with  blood 
and  serum. 

Glaucoma. — The  evidence  that  glaucoma  may 
be  causally  connected  with  diseased  teeth 
is  divided.  Experimentally,  Von  Hip|3el  and 
Grunliagen  found  that  in  animals,  if  the  aorta 
were  compressed  and  the  trigeminal  nerve 
then  stimulated,  a  greatly  increased  tension  of 
the  eyeball  resulted.  Power  and  Reber  are  of 
opinion  that  reflex  dental  irritation  may  be  a 
factor  in  tlireatening  glaucoma,  and  the  former 
(40)  records  a  case  (tension  +  1)  in  wliich  a 
marked  improvement  was  affected  by  the 
extraction  of  three  carious  teeth.  On  the 
other  hand  Priestly  Smith,  after  examining 
the  tension  of  the  eyeball  in  a  number  of  cases 
of  odontalgia,  is  of  opinion  that  the  two  con- 
ditions are  not  related.  It  must  be  remembered 
too  that  the  precise  pathology  of  glaucoma  is 
not  yet  fully  worked  out,  and  hence  it  is  one 
of  that  class  of  lesions  to  which  a  "  reflex  " 
origin  is  apt  to  be  assigned  in  the  absence  of 
any  other  obvious  cause.  If  diseased  teeth  act 
reflexly  in  "  causing  "  a  raised  tension  of  the 
eye  at  all,  it  is  probably  by  increasing  the 
amount  of  blood  (and  fluid)  in  an  eye  already 
"  predisposed  "  to  glaucoma.  Odontalgia  and 
glaucoma  frequently  synchronize,  but  in  such 
cases  the  dental  pain  is  usually  a  part  of  the 
general  neuralgia  set  up  by  the  glaucoma,  and 
disappears  when  the  latter  is  relieved-. 

Instances  of  Exophthalmos  Ijeing  related  in  a 
reflex  manner  to  diseased  teeth  are  by  no  means 
uncommon,  and  are  to  be  exjilained  in  a  similar 
manner  to  the  above. 

Superficial  Hyperaemia,  or  flushing  of  the  skin 
in  definite  areas  of  the  face,  forehead,  or  temple, 
due  to  reflex  vaso-motor  stimulation  during 
odontalgia,  is  well  known,  and  of  common 
occurrence. 

Affections  arising  from  Stimulation  of  Secretory 
Nerves 

Lacrimaiion. — A  reflex  flow  of  tears,  duo  to 
paroxysms  of  pain  in  inflammation  of  the 
pulp  or  periodontal  membrane,  is  observed  so 
frequently  as  to  need  no  comment. 

Salivation,  in  a  similar  manner,  is  frequently 
brought  about  by  reflex  stimulation  of  the 
chorda  tympani.  This  is  usually  quite  tran- 
sient, but  the  flow  of  saliva  may  remain  excessive 
for  a  considerable  time. 

Hyperhydrosis. — A  profuse   secretion   of   the 


732 


sweat  glands  may  be  incited  reflexly  by  any 
severe  pain,  but  the  same  thing  may  occur 
without  excessive  pain  being  present. 

Two  cases  of  hyperhydrosis  are  recorded  by 
Darguies  (10),  wliich  were  caused  by  "  masti- 
cation '',  though  no  mention  is  made  of  the 
condition  of  the  teeth. 

A  case  has  recently  come  under  the  notice  of 
the  writer  in  wliich  the  patient,  a  healthy  young 
man  of  19,  exhibited  most  profuse  hyperhydrosis 
of  the  frontal  and  malar  regions  whenever 
cavities  in  his  teeth  (upper  incisors)  were  being 
excavated,  although  he  stoutly  denied  feeling 
the  slightest  pain,  and  was  not  in  the  least 
"  nervous  ". 

Coryza.- — Hypersecretion  of  the  nasal  mucous 
membrane  may  occasionally  be  traced  to  reflex 
irritation  from  diseased  teeth. 

Rousseau-Decelle  (47)  recounts  a  case  of 
coryza  on  the  left  side  (with  other  complications), 
which  seemed  to  be  dependent  upon  lesions  of 
the  two  left  upper  incisors ;  on  the  teeth  being 
treated  the  symptoms  at  once  abated. 

Collett  (8)  relates  a  case  of  a  patient  -who 
developed  a  coryza  accompanied  by  neuralgia, 
whicli  had  lasted  for  three  or  four  weeks  despite 
all  local,  nasal,  and  general  treatment.  An 
upper  premolar  was  then  found  to  be  affected 
wiiYi  periodontitis  and  was  extracted ;  no  pus 
was  found.  The  neuralgia  had  disappeared 
next  day,  and  the  coryza  also  after  the  next 
three  days. 

Affections  arising  from  Stimulation  or  Inhibition 
of  Nerves  of  Special  Sense 

As  an  explanation  of  the  possibility  of  such 
affections  arising  reflexly  from  diseased  teeth, 
the  reader  is  reminded  of  t\\o  physiological 
experiments. 

(1)  Reflex  Stimulation.- — It  is  found  that  if 
an  animal  is  very  lightly  anaesthetized  certain 
cortical  areas  of  the  brain  become  sensitive  to 
stimuli  (which  would  not  ordinarily  be  per- 
ceived), provided  that  numerous  other  sensory 
impulses  are  being  received  from  the  periphery 
at  the  same  time. 

(2)  Reflex  Inhibition. — Acid  placed  on  a  frog's 
foot  causes  instant  reflex  retraction.  If  now  a 
tight  ligature  is  placed  round  the  arm  of  the 
frog,  the  acid  when  applied  to  the  foot  either 
causes  no  reflex  action  at  all,  or  a  very  much 
delayed  one,  i.  e.  the  impulses  from  the  arm 
have  "  monopoUzed  "  the  attention  of  the 
brain.  In  a  .similar  manner  impulses  arriving 
from  the  dental  branches  of  the  trigeminal  nerve 
may  monopolize  the  attention  of  the  brain  to 
the  exclusion  of  impulses,  say,  from  the  optic 
nerve. 

Amaurosis  and  Amblyopia.— Veiy  many  cases 
of  such  conditions  have  been  placed  on  record 


from  time  to  time  as  reflex  neuroses  arising  from 
dental  disease.  Some  of  them  would  now 
probably  be  recognized  as  being  due  to  direct 
extension  via  the  maxUlary  sinus,  veins,  or 
perivascular  lymph  vessels,  causing  an  acute 
optic  neuritis.  Nevertheless  there  are  cases  in 
which  this  seems  to  be  excluded. 

Hancock  records  a  case  in  which  a  patient 
had  been  blind  for  over  a  month  ;  there  had  been 
no  preliminary  symptoms ;  the  onset  was  quite 
sudden,  and  no  structural  changes  in  the  eye 
could  be  found.  A  diagnosis  of  reflex  dental 
irritation  was  made,  and  six  teeth  were  extrac-. 
ted.  Withm  a  few  hours  light  became  visible, 
and  during  the  week  following  the  sight  com- 
pletely returned.  The  only  other  treatment 
adopted  was  the  administration  of  aperients. 

A  case  of  sudden  amaurosis  following  the 
extraction  of  a  carious  and  very  painful  upper 
molar  is  described  by  Santamaria  (50). 

Cases  were  also  related  by  Coleman  (7),  Sir 
Thomas  Watson  (59),  De  Witt  (11),  and  Gale- 
zowski  (14).  The  latter  states  that  reflex 
amblyopia  is  frequently  due  to  teeth,  and 
"almost  invariably  "  is  due  to  upper  molars; 
"  almost  never  "  from  the  incisors,  and  very 
rarely  from  the  canines.  Graefe  and  Saemisch 
(18)  are  of  opinion  that  "  cases  of  amaurosis 
and  amblyopia  often  improve  after  extraction  of 
diseased  teeth  ". 

Wecker  (60),  discussing  amblyopia  and 
amaurosis,  speaks  of  "  L'influence  desastreuse 
que  I'irritation  des  nerfs  dentakes  pent  exercer 
sur  la  vision  ". 

Deafness. — This,  like  amaurosis,  may  be 
occasionally  caused  reflexly  by  diseased  teeth. 

Mummery  (32)  records  "  A  case  of  deafness 
on  the  left  side  from  the  delayed  eruption  of  a 
third  upper  molar ;  very  considerable  deafness 
had  existed  for  some  months,  which  was  much 
relieved  immediately  on  the  extraction  of  the 
tooth,  hearing  being  fully  restored  the  same 
day." 

Catlin  relates  an  instance  of  deafness  that  had 
lasted  for  four  days,  and  in  wliich  hearing 
returned  within  an  hour  of  the  extraction  of  a 
right  lower  molar.  Dr.  Maughan,  in  referring 
to  the  case,  says  :  "  The  iiiliibition  of  hearing 
is  readily  understood  when  one  remembers 
the  proximity  of  the  median  root  nuclei  to  the 
acoustic  nerve  centre." 

Photophobia. — Increased  sensibility  of  the 
retina  to  light  seems  in  some  cases  to  be  induced 
through  reflex  dental  irritation ;  instances  are 
related  by  Teirlink  (M),  Hay,  and  De  Witt  (11). 

The  latter  records  a  case  of  lacrimation  and 
photophobia  of  one  eye  of  prolonged  standing ; 
the  condition  was  intensified  by  dietetic  errors, 
but  yielded  completely  after  the  extraction  of 
a  carious  tooth.  J.  Hutchin.son  (23)  has  also 
recorded    a    case    of    acute    photophobia    in    a 


733 


woman  of  28,  which  was  completely  cured  by 
the  extraction  of  a  carious  upper  molar,  no 
other  treatment  having  been  adopted. 

Tinnitus  Aurium  {murmurs  or  noises  in  the 
ears)  is,ina  similar  manner,  saidto be  occasionally 
set  up  reflexly  by  the  teeth. 

Inhibition  of  Motor  Nerves 

Some  authorities  are  of  opinion  that  reflex 
inhibition  of  motor  nerves  does  not  occur,  but 
the  balance  of  modern  physiological  oinnion 
seems  to  be  in  favour  of  such  action  taking 
place. 

Head's  explanation  of  ""  spread  '"  as  due  to 
lowered  phj-sical  conditions  may  be  taken  as 
explaining  muscular  paresis  in  remote  parts 
sometimes  found  to  be  dependent  on  the  teeth  ; 
there  are  other  ways  also  in  wluch  reflex  paresis 
is  possible,  but  they  cannot  be  discussed  here. 
Cases  of  this  nature  have  been  recorded  by 
competent  observers,  so  that  this  classification 
is  adhered  to.  It  is  important,  however,  to 
recognize  that  referred  pain,  or  neuralgia,  may 
cause  a  patient  involuntarily  to  simulate  a 
paralysis  in  some  cases — o«  ing  to  the  fact  that 
movement  is  carefully  avoided  in  order  to 
ob\'iate  any  increased  pain. 

Facial  Paralysis. — Manj-  cases  of  Bells  palsy 
are  on  record  that  ajiparently  have  a  causal 
relationship  \\ith  diseased  teeth.  Some  of  these 
would  appear  to  be  true  reflex  neuroses ;  others 
are  due  to  the  imphcation  of  the  facial  nerve 
in  inflammatory  products  from  the  teeth.  It 
is  also  well  to  remember  that  the  most  frequent 
cause  of  facial  paralysis  is  exposure  to  cold,  and 
this  same  thing  often  originates  an  attack  of 
odontalgia,  and  the  two  conditions  thus  merely 
synchronize. 

Instances  of  this  affection  are  related  by 
Gabriel  (13),  Garretson  (15),  Poundall  (39),  and 
Salter  (49). 

Ocular  Paralyses — Ptosis,  Paralytic  Strabismus, 
Paralysed  Accommodation,  Mydriasis  and  Paraly- 
sis of  the  Orbicularis  Palpebrarum,  have  all  been 
ascribed  in  a  few  cases  to  reflex  irritation  from 
diseased  teeth. 

Such  cases  are  recorded  by  Nicol  (33)  and 
Power  (41);  and  Gutmann  (19)  and  Reber  (45) 
are  of  oi^imon  that  such  paretic  conditions  may 
often  be  connected  with  disease  of  the  teeth, 
and  improve  upon  treatment  of  the  dental 
lesions. 

Mummery  {loc.  cil.)  records  the  following  case 
of  ptosis  :  "  A  lady,  aged  30,  consulted  me 
about  ptosis  of  the  left  eye,  accompanied  by 
complete  blanching  of  a  lock  of  hail-  over  the 
left  temple.  There  was  no  toothache,  but 
neuralgic  pain  in  the  left  temporal  region,  from 
which  she  suffered  previous  to  the  blanching  of 
the  hair.  The  second  left  upper  molar  I  found 
tender  on  percussion,  and,  tiuding  it  contained  a 


partially  dead  pulp  beneath  a  filling,  I  removed 
the  tooth.  The  ptosis  was  relieved  the  next 
day,  but  the  lock  of  hair  remained  permanently 
white." 

With  regard  to  paralysed  accommodation, 
Schmidt  found  a  certain  degree  present  in  73 
out  of  93  cases  of  dental  disease  examined,  whilst 
Priestly  Smith  only  found  it  present  in  1  out 
of  16  cases  of  odontalgia.  Norris  and  Oliver 
(34)  refer  to  paralysed  accommodation  as 
"  perhaps  the  most  frequent  ocular  disturbance 
noted  in  connection  with  dental  irritation  ". 

Paralysis    of    Arm. — Several    cases    of    this- 
nature  have  been  recorded,  the   paresis  in  no 
case  being  complete,  but  varying  from  a  "  sense 
of  lassitude  in  the  arm  "  to  "  inability  to  raise 
the  arm  ". 

The  case  recorded  by  Salter  seems  to  have 
been  the  most  severe.  The  patient  suffered 
considerable  pain  in  the  arm,  accompanied  by 
"  total  inability  to  use  the  arm — to  raise  it.  or 
to  grasp  with  the  hand  ".  A  third  lower  molar, 
which  was  carious  and  was  erupting  with  diffi- 
culty, was  extracted,  and  almost  inin.ediately 
afterwards  the  arm  symptoms  '"  vanished 
completely  ". 

Mummery  states  that  in  his  case,  whenever 
the  patient  sufi^ered  from  bad  pain  in  the  left 
lower  molar,  he  could  only  raise  his  left  arm 
with  difficulty,  and  "experienced  a  sense  of 
weight  and  fatigue  in  the  arm  almost  amounting 
to  pain '". 

The  wTiter  has  seen  three  cases  of  brachial 
neuralgia  due  to  inflammation  of  the  pulp 
(painless)  of  the  lower  premolars,  and  each  case 
has  been  accompanied  by  difficulty  in  raising  the 
arm,  but  it  was  impossible  to  say  just  how  much 
of  this  was  due  to  pain  ;  certainly  in  one  case 
movement  of  the  arm  increased  the  pain,  and 
for  this  reason  it  was  very  carefully  held  as 
still  as  possible. 

Affections  arising  from  Interference  wilh  the 
Trophic  Functions  of  Nerves 

It  is  impossible  to  believe  that  actual  inflam- 
mation, as  it  is  now  understood,  could  be  caused 
per  se  by  reflex  dental  irritation.  Yet  that  such 
reflex  irritation  has  some  influence  over  the 
origin  and  course  of  inflammatory  lesions  in 
certain  regions  is  a  clinical  fact.  The  mode  of 
such  influence  may  be  either  as  Hilton  (21)  said 
— that  the  reflex  irritation  from  the  teeth  leads 
to  interference  with  the  nutritive  function  of 
the  nerves  suppl\ang  other  regions ;  or  as  Robert 
Hutchison  (25,  p.  555)  believes — that  it  "  has 
to  do  with  a  congestion  of  the  vessels  w hich  may 
be  reflexly  induced  through  the  medium  of  the 
trigeminal  nerve  ".  More  probably  the  eflects 
are  produced  by  a  combination  of  the  two 
causes,  and  in  either  case  the  tissues  would  be 


734 


rendered   less   resistant   to  invasion  by  micro- 
organisms. 

White  Hair.—Both.  Mummery  (32)  and  Hilton 
(22)  relate  cases  in  which  the  hair  on  the  temjJe 
became  more  or  less  suddenly  white  during 
attacks  of  severe  neuralgia  originating  in  the 
teeth.  In  Mummery's  case  the  bleaching  of 
the  hair  was  accompanied  by  ptosis.  The  latter 
condition  disappeared  after  the  extraction  of  an 
upper  molar  containing  a  partially  necrosed  pulp 
under  a  filling,  though  it  is  important  to  note 
that  no  "  toothache  "  had  been  felt. 
"  Alopecia  Areata. — The  frequent  association 
of  tliis  condition  with  dental  lesions  has  been 
worked  out  more  especially  by  French  authori- 
ties, and  by  Jacquet  particularly.  Rousseau- 
Decelle  (47)  goes  so  far  as  to  say  that  reflex 
dental  irritation  causes  one-third  of  the  total 
number  of  cases  of  alopecia.  He  further  gives 
it  as  his  opinion  that  the  loss  of  hair  is  on  the 
same  side  as  the  pain  and  is  more  frequent  on 
the  left  side,  and  that  alopecia  tends  to  follow 
lesions  of  the  gums  and  alveoli  rather  than  of 
the  teeth  themselves. 

Amongst  others,  the  following  case  is  cited  : 
"  In  a  patient  presenting  an  area  of  baldness 
on  the  left  side  of  the  nape  for  over  a  year,  the 
treatment  of  various  teeth,  including  the 
'  extraction '  of  the  third  left  lower  molar, 
produced  no  improvement,  till  Monier  dis- 
covered and  removed  a  large  fragment  of  the 
po.sterior  root  of  that  tooth,  when  the  alopecia 
disappeared  in  a  month." 

Another  case  of  alopecia  (of  the  moustache) 
is  also  related  by  the  same  author ;  this  was 
cured  in  ten  days  by  the  treatment  of  the  two 
left  upper  incisors.  Underwood  (56)  has  also 
recorded  a  case  of  loss  of  hair  caused  reflexly 
by  the  teeth.  Alopecia  of  dental  origin  is  said 
to  be  small  in  area  and  multiple  ;  extensive  loss 
of  hair  is  usually  due  to  other  causes. 

Ulceration  of  the  Face,  Mouth,  or  Cornea. 
Tliere  can  be  no  doubt,  and  nearly  all  authorities 
are  agreed,  that  the  irritation  arising  from 
diseased  teeth  tends  to  prolong  such  lesions, 
even  if  it  does  not  actually  predispose  the  part 
to  the  initial  attack  of  inflammation. 

Two  cases  of  severe  corneal  inflammation, 
apparently  associated  with  "complicated" 
teething,  are  reported  by  Besignorie  (3).  The 
writer  can  cite  a  case  of  ulceration  of  the  face 
on  the  right  side  between  the  malar  jDrominence 
and  the  nose,  which  resisted  all  treatment  for 
a  considerable  time,  and  only  yielded  after 
devitalization  of  an  exposed  pulp  in  the  right 
upper  canine,  though,  it  should  be  noted,  there 
was  no  dental  pain. 

Conjunctivitis  and  Iritis. — Similar  remarks 
apply  to  these  lesions,  and  it  is  a  matter  of  fairly 
frequent  observation  that  the  ophthalmic 
treatment    is   in    some    cases    only    successful 


after  the  elimination  of  pathological  dental 
stimuli. 

The  WTiter  has  certainly  seen  such  cases  of 
conjunctivitis.  Wendell  Reber  (45),  Adolph 
Gutmann  (19),  Smale  and  Colyer  (53,  p.  756), 
and  Norris  and  Oliver  (34),  also  express  similar 
ojjinions. 

Furred  Tongue. — This  condition  occasionally 
exists  on  one  side  only,  and  is  associated  \vith 
a  diseased  tooth  (or  teeth)  on  that  side.  It  is 
sometimes  quoted  as  an  example  of  interference 
with  the  trophic  function  of  the  nerves  supplying 
the  tongue  ;  but  it  is  equally  likely  to  be  caused 
by  deficient  mastication  on  that  side,  just  as  the 
teeth  and  gums  on  the  same  side  are  likely  to  be 
covered  with  epitheUal  and  food  debris. 

Otorrhoea. — That  dental  irritation  is  capable 
of  exerting  a  neurotrophic  influence  in  this 
condition  would  seem  to  be  so  from  the  case 
recorded  by  Hilton  (22),  in  which  a  persistent 
flow  of  pus  from  the  ear  only  gave  way  to  treat- 
ment after  the  removal  of  a  diseased  lower 
molar.  Urban  Pritchard  (42)  has  also  stated 
that  in  his  opinion  "  dental  irritation  is  a  factor 
in  these  cases  of  suf)purative  otitis  media,  both 
in  the  causation  itself  and  also  in  the  keeping 
up  of  the  inflammatory  condition." 

Diagnosis  of  Reflex  Affections 

The  dental  lesion  giving  rise  to  such  reflex 
affections  as  have  been  described  may  be  in- 
flammation of  the  pulp  (due  to  exposure  of 
the  pulp  or  penetrating  caries  without  loss  of 
substance),  calcareous  degeneration  of  the  pulp, 
periodontitis  in  any  of  its  numerous  forms,  or 
impaction  of  an  erupting  tooth. 

It  cannot  be  said  definitely  which  of  these 
lesions  is  most  prone  to  give  rise  to  reflex 
affections,  but  the  writer  is  of  opinion  that 
gradually  acquired  exposures  of  the  pulp  and 
impacted  third  lower  molars  are  more  often 
than  others  the  cause  of  the  trouble.  More 
important,  however,  than  the  class  of  lesion 
is  the  absence  of  local  dental  pain.  This  fact  is 
to  be  noticed  again  and  again  in  records  of 
such  cases,  and  is  of  great  value  from  a  diagnostic 
point  of  view.  As  a  general  rule,  or  "law", 
it  may  be  said  that  if  the  patient  is  complaining 
of  symptoms  that  maij  he  reflex,  and  a  dented 
condition  is  discovered  that  shoidd  normally  be 
causing  pain,  but  is  not,  then  that  dental  lesion  is 
probably  the  source  of  the  reflex  affection. 

With  regard  to  alveolar  abscess,  although  the 
presence  of  pus  around  a  tooth  suggests  the 
probability  of  other  affections,  as  being  due  to 
direct  extension,  yet  it  must  not  be  forgotten 
that  an  alveolar  abscess  (especiaUy  in  its  early 
and  acute  stage)  may  give  rise  to  powerful 
sen.sory  impulses,  wlrich  may  be  reflected  in 
any  of  the  ways  mentioned. 


735 


It  is  often  easy  to  make  the  mistake  of 
diagnosing  a  reflex  paralysis  ■\\hen  only  neural- 
gia is  present — the  pain  i^revontrng  voluntary 
movement ;  this  may  be  eliminated  by  eliciting 
involuntary  movement  in  the  usual  manner. 
A  patient  suffering  from  hysteria  may  present 
combinations  of  pain  and  reflex  affections,  but 
the  combinations  may  be  very  unusual  or  im- 
possible. With  regard  to  hj^persecretion,  Sir 
Victor  Horsley  is  of  opinion  that  when  this  is 
definitely  associated  with  the  onset  of  pain,  the 
condition  is  an  "organic  "'  and  not  a  "func- 
tional "  one. 

In  every  case  one  has  to  guard  against  the 
fallacy  of  post  hoc  ergo  propter  hoc  in  ascribing 
reflex  affections  to  diseased  teeth. 

H.  P.  P. 


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June  1909,  Vol.  LI.  p.  682. 


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CHAPTP]R  XLIX 


DISEASES   OF  THE   MUCOUS   MEMBRANE   OF   THE   MOUTH- 
IMMOBILITY  OF  THE   MANDIBLE 


DISEASES  OF  THE  MUCOUS  MEMBRANE 

A  siJiPLE  or  germ-free  inflammatory  process 
in  the  mouth,  though  difficult  to  imagine, 
cannot  he  denied  existence.  The  earHest  stages 
of  reaction  to  injury  caused  by  burns,  violence, 
or  chemical  action,  ^\  ill  certainly  be  independent 
of  germs,  but  not  for  long,  unless  extraordinary 
antiseptic  precautions  are  possible ;  but  the 
nearer  the  aseptic  ideal  is  approached,  the 
'■  simpler  "  will  be  the  reaction  after  injury — 
mouth  operation  cases  in  which  the  jarepara- 
tion  and  after-treatment  have  been  especially 
directed  to  oral  asepsis  illustrate  this  point 
well. 

Herpetic  eruptions  of  the  mouth  have  been 
described,  but  must  be  of  some  rarity,  since 
the  writer  has  never  yet  met  with  a  mouth 
eruption  with  a  preliminary  history  of  zonular 
pain  such  as  is  found  in  true  herpes.  The 
condition  would  probably  be  germ-free  in  its 
inception. 

Traumatic  Ulcer  of  the  cheek,  lips,  or  tongue, 
may  be  caused  by  the  edge  of  a  broken  tooth, 
and  in  any  part  of  the  mouth  by  violence. 

The  traumatic  origin  of  many  ulcers  of  the 
mouth  is  probably  often  overlooked.  Injury 
by  the  glancing  blow  of  a  tooth-brush  not  in- 
frequently results  in  an  ulcer  of  which  the  origin 
has  been  forgotten  ;  and  occurring  at  a  particular 
period,  such  as  pregnancy,  the  ulcer  and  the 
general  state  are  apt  to  become  aetiologically 
comiected  in  the  mind  of  an  observer  forgetful 
of  other  possibilities.  That  such  ulcers  should 
become  more  intractalile,  and  be  more  readily 
produced  in  enfeebled  general  conditions  (among 
which,  ho\\ever,  the  writer  is  loath  to  include 
normal  pregnancy  or  lactation),  is  self-evident ; 
but  the  starting-point  is  extrinsic  to  the  disease 
with  which  it  eventually  finds  itself  aetiologic- 
ally coupled.  To  forgotten  trauma,  and  to  the 
failure  to  realize  the  universal  prevalence  of 
dental  sepsis,  the  writer  considers  is  owing  the 
conception  of  such  conditions  as  cUabetic  and 
tabetic  ulcers  of  the  mouth  as  sj)ecial  entities, 
and  the  descriptions  of  ulcers  of  lactation, 
anaemia,  etc. 

Habitual  use  of  the  microscope  and  of  the 
sense  of  smell  after  passing  a  wisp  of  cotton- 


736 


wool  through  the  inter-dental  spaces  or  into 
the  periodontal  j)ockets  will  soon  convince 
the  most  sceptical  of  the  prevalence  of  dental 
sejDsis  ;  to  its  presence  most  of  the  inflammatory 
and  ulcerative  conditions  of  the  mucous  mem- 
brane of  the  mouth  met  with  are  due,  and  all 
are  influenced  by  it. 

Septic  Ulceration  is  the  commonest  form  of 
ulcer  found  in  the  mouth.  It  occurs  connnonly 
under  the  edges  of  tartar,  on  the  cheeks,  lips, 
and  "corners  of  the  mouth",  in  the  buccal 
sulcus  (vestibule  of  the  mouth),  on  the  tongue 
or  floor  of  the  mouth  ojjposite  septic  teeth, 
and  often  also  on  the  palate.  "  Cracked  lip  " 
is  an  ulceration  of  dental  sepsis.  The  com- 
monest origin  of  epithelioma  of  the  tongue 
and  mouth  generally  is  a  neglected  septic  ulcera- 
tion. When  the  septic  teeth  are  also  ragged 
and  capable  of  inflicting  mechanical  injury, 
traumatic  ulceration  is  produced,  but  it  is 
the  chronic  sepsis  that  brings  the  danger  of 
malignancy. 

There  is  an  acute  form  of  ulceration  known 
as  ulcerative  stomatitis,  which  may  for  all  prac- 
tical purposes  be  classed  as  a  septic  ulceration, 
though  the  causative  bacterium  is  uncertain. 
It  is  commonest  in  children,  and  especially 
prone  to  occur  in  eiifeebled  states,  as  during 
specific  fevers,  and  when  dental  cleanliness  has 
been  neglected.  It  is  characterized  by  a  necrotic 
ulceration  of  the  gum  edge  round  one  or  more 
teeth,  which  if  unchecked  tends  to  spread 
round  the  whole  dental  arch.  The  adjacent 
cheek  surfaces  are  often  mfected  by  contact, 
and  discrete  ulcers  are  sometimes  found  on  the 
alveolar  muco-periosteum.  The  temperature  is 
raised,  and  the  neighbouring  lymph  glands 
are  swollen  and  tender.  The  disease  may 
progress  to  loss  of  teeth,  necrosis  of  bone,  and 
to  gangrene  of  soft  parts,  resulting  in  cicatricial 
closure  of  the  jaws.  It  has  been  described  as 
occurring  in  epidemics,  and  seems  to  be  infective 
among  the  human  race. 

Treatment. — The  disease  can  be  prevented  by 
dental  cleaiJiness,  and  generally  is  readily 
curable  by  use  of  chlorate  of  potash  internally 
— for  cliildren  gr.  iij-v,  for  adults  gr.  x-xv, 
three  times  a  day- — and  attention  to  local 
cleansing. 


737 


The  gum  margins  of  the  teetli  must  be  care- 
fully cleansed  at  least  twice  daily,  and  loose 
teeth  must  be  remov'ed.  The"  patient  should 
be  isolated.  To  clean  the  necks  of  the  teeth, 
and  as  a  mouth-wash —    ■ 


R 

Pot.  Chlor. 

Glycerin. 

Aq.  ad 
M.  ft.  lot. 


gr.  .X. 

5  i- 
5  J- 


Chronic  Generalized  Septic  Stomatilis  is  a 
common  result  of  dental  sepsis.  The  tongue 
is  swollen,  fissured,  and  indented  by  the  teeth, 
the  whole  mucous  memlirane  of  the  mouth — 
of  the  soft  palate  and  u\'ula,  and  that  covering 
the  hard  palate,  cheeks,  and  lips — is  swollen 
and  oedematous,  and  the  condition  usually 
spreads  to  the  pharynx.  The  soft  palate  is 
injected,  but  the  cheeks,  lips,  and  tongue  are 
often  in  long-standing  cases  sodden  and  of  grajash 
appearance.  The  epithelium  is  in  parts  thinned 
away,  and  in  parts  heaped  up  into  an  ichthyotic 
condition,  which  is  not  infrequently  the  precursor 
of  epithelioma.  This  ichthyotic  condition  has 
been  especially  described  as  occurring  on  the 
tongue,  but  is  to  be  found  also  on  the  hard 
palate,  cheeks,  and  mucous  membrane  of  the 
alveolar  borders.  Chronic  inflammatory  infiltra- 
tion leads  to  destruction  of  the  glandular  and 
papillary  elements,  especially  of  the  tongue, 
leaving  patches  of  the  mucous  membrane  thin 
and  of  a  glazed  bluish  colour.  The  whole  mouth 
is  often  sore  and  tender,  "  cracks  "  on  the  lips 
are  frequent,  and  sometimes  a  chronic  swelling 
of  the  lips  is  an  outstanding  feature.  There  is 
generally  excessive  secretion  of  saliva  and  mucus, 
and  at  times  this  symptom  literally  drowns 
all  others.  Ill-smelling  breath  is  common,  but 
may  be  absent,  and  sometimes  there  is  com- 
plaint of  a  foul  taste ;  but  usually  the  patient 
is  unconscious  either  of  taste  or  smell.  The 
sub-mental  and  cervical  lymph  glands  are 
generally  enlarged. 

Chronic  general  stomatitis  is  found  both  in 
men  and  women,  and  the  swollen  fissured  tongue 
is  often  seen  in  children.  In  syphilitic  sub- 
jects it  may  determine  the  onset  of  specific 
glossitis,  which  is  prone  to  run  on  to  malignancy. 

In  the  course  of  the  disease,  superficial  and 
often  recurrent  ulceration  of  one  or  other  part 
of  the  mouth  is  frequent,  and  the  salivary 
glands  may  become  infected,  inflammatory  swell- 
ing sometimes  ending  in  suppuration.  As  would 
be  expected,  the  gums  are  generally  swollen, 
either  by  chronic  oedema  or  by  inflammatory 
h\^ertrophy  (granuloma) ;  but  in  some  cases 
they  are  undergoitig  the  destructive  stages  of 
the  drier  forms  of  "  periodontal  disease  " — in 
practically  every  case  of  chronic  septic  stomatitis 
there  is  well-marked  periodontal  disease.  This 
24 


inflammatory  hypertrophy  not  infrequently  runs 
on  to  locahzed  or  generalized  hypertrophj'  of 
the  gums,  and  sometimes  to  sarcoma. 

Occasionally,  overgrown  masses  of  mucous 
membrane  of  septic  origin  meet  in  the  m.id-line 
of  the  vault  of  the  palate.  Slow  fibrous  over- 
growth of  the  muco-periosteum  is  often  seen 
in  the  course  of  the  disease,  and  again  the 
overgrown  masses  on  the  maxillary  tuberosities 
not  infrequently  meet  in  the  median  line.  The 
bone  in  these  cases  of  fibrous  overgrowth 
partakes  of  the  general  hypertrophy,  becoming 
enlarged,  and  dense  and  granular  in  section, 
as  a  result  of  sclerosing  osteitis.  The  transition 
from  such  a  process  to  a  diffuse  osteoma  is  an 
obvious  possibility ;  but  the  source  of  sepsis 
need  not  be  a  generalized  septic  inflammation — 
a  small  focus  may  suffice. 

Chronic  general  septic  stomatitis  is  a  result 
of  dental  sepsis.  The  earliest  stage  is  a  marginal 
gingivitis  due  to  infection  of  the  circum-dental 
sulcus,  a  condition  that  makes  good  its  foot- 
ing in  early  cliildhood.  From  this  point  the 
infection  spreads  over  the  mucous  membrane 
of  the  mouth.  In  well-established  cases  the 
teeth  are  tartar-coated,  and  decompo.sing  food 
and  germs  of  various  kinds  are  held  up  in  their 
interstices  and  around  them,  especially  at  the 
gingival  margin.  The  gums  are  swollen  and 
bleed  readily,  and  pus  may  be  found  exuding 
from  under  their  edges ;  but  a  far  less  obtrusive 
clinical  condition  of  the  teeth  and  gums  than 
this  may  represent  a  serious  condition  of  dental 
sepsis. 

Treatment. — Thorough  dental  asepsis  is  the 
only  treatment,  and  free  extraction  of  teeth  is 
the  most  efficient  way  of  securing  an  aseptic 
condition.  Short  of  this,  thorough  scaling, 
destruction  of  all  pyorrhoeic  pockets,  and  con- 
stant daily  attention  to  the  minutiae  of  me- 
chanical dental  cleansing  must  be  insisted  on. 
The  artifact  sepsis  of  ill-made  fillings,  and  of 
all  forms  of  artificial  teeth,  must  be  re- 
moved. Large  masses  of  hypeitrophied  muco- 
periosteum  and  hone  will  have  to  be  cut  away 
if  causing  inconvenience,  but  granulomatous 
enlargements  of  the  lips  and  cheeks  will  always 
subside  after  removal  of  the  irritant,  if  given 
time,  though  a  year  or  more  may  be  needed. 

Mercurial  Stomatitis  is  now  a  rare  condition. 
It  may  be  caused  by  inhalation  of  the  vapour 
of  mercury,  or  by  over-dose  medicinally.  The 
mucous  membrane  is  swollen,  and  there  is  ex- 
cessive flow  of  saliva,  leading  to  the  designation 
■ptyalism.  The  teeth  become  loosened,  and  if 
unchecked  the  disease  runs  on  to  loss  of  teeth 
and  necrosis  of  bone.  In  the  absence  of  dental 
sepsis  mercurial  stomatitis  does  not  occur — the 
disease  is  a  septic  infection  of  tissues  lowered 
in  vitality.  It  may  be  prevented  by  thorough 
dental  asepsis  before   and  during  a  course   of 


738 


mercurial  treatment.  When  the  condition  occurs 
administration  of  mercury  must  be  stopped  and 
dental  asepsis  established  as  rapidly  as  possible. 

Fungus  Infection 

Thrush  is  due  to  the  growth  on  and  among  the 
cells  of  the  epithelium  of  a  fungus,  oidium 
albicans  (syn.  saccharomyces  albicmis).  Small 
raised  adherent  greyish-white  spots  are  found 
on  the  mucous  membrane  of  the  mouth ;  these 
enlarge  and  coalesce,  forming  j)atches,  and  even 
an  extensive  membrane.  The  growth  can  be 
peeled  off,  leaving  a  bleeding  surface  beneath. 
Later,  these  patches  peel  away  spontaneously. 
Tlie  disease  occurs  in  dirtily  fed  infants  and 
in  debilitated  adults.  The  intestinal  tract  is 
generally  unhealthy  at  the  same  time. 

Treatment. — All  feeding  apparatus  must  be 
carefully  cleaned,  and  the  mouth  wij)ed  out 
before  and  after  each  meal  with  clean  lint 
dipped  in  a  solution  of  borax  in  glycerine  and 
water. 

R 


Sod.  Bibor.   . 

•       oij 

Glycerin. 

•      O  i 

Aq.  ad   . 

•       3    J 

M.  ft.  lot. 

Infection  by  aspergillus  nigrescens,  giving  rise 
to  the  formation  of  a  dark  membrane  on  the 
palate,  has  been  recorded.  Sponging  with 
antiseptic  solutions  is  sufficient  to  cure  the 
condition  (2). 

In  chronic  lead-poisoning  (plumbism)  a  blue 
line  is  often  found  on  the  margin  of  the  gums 
round  the  teeth.  Where  there  are  no  teeth  it 
is  aljsent.  It  is  due  to  the  deposit  in  the  gum 
of  lead  sulphide,  tlie  lead  circulating  in  the 
blood  finding  its  complement  of  sulphur  in  the 
debris  stagnant  round  the  teeth.  Sometimes 
inlialation  of  lead  dust  or  vapours  leads  to  a 
blue  deposit  on  the  gum.  This  deposit  can 
be  removed  mechanically.  The  '"  lead -line  "' 
may  be  an  early  sign  of  plumbism. 

Syphilis 

Primary  syphilitic  infection  of  the  mouth 
may  occur  by  contact  with  any  source  of  infection 
— possibly  a  dentist's  instrument.  Owing  to 
the  looseness  of  the  subnuicous  tissues  of  the 
lips,  cheeks,  and  floor  of  the  mouth,  the  classical 
symptom  of  induration  may  be  wanting  in  these 
parts.  Tliorough  dental  asepsis  will  almost 
banish  the  later  syphilitic  manifestations  from 
the  mucous  membrane  of  the  mouth.  They  are 
seen  in  the  following  forms:  (1)  as  "mucous 
tubercles  " — raised  infiltrated  patches  of  mucous 
membrane  exuding  a  serous  discharge,  and  as 
shallow-spreading  ulceration ;  both  these  forms 
are  very  infectious   and  are  usually  found  on 


both  sides  of  the  mouth,  and  occur  in  the  earlier 
stages  of  the  disease ;  (2)  as  more  chronic 
"  gummatous  "  infiltration  of  the  mucous  mem- 
brane, occurring  late  in  the  disease,  asymmetric- 
ally and  painless,  and  running  on  to  ulceration 
and  sloughing,  and  if  arising  over  the  bone,  to 
bone  destruction ;  (3)  as  part  of  congenital 
syphilis. 

The  dentist  must  remember  that  he  may 
readily  transmit  and  readily  acquire  syphiUs 
in  the  course  of  his  work,  and  that  all  active 
syphilitic  lesions  are  infectious. 

Tubercular  Ulceration  of  the  mucous  mem- 
brane of  the  mouth  is  a  rare  condition.  It  is 
generally  slow,  and  enlarges  in  spite  of  anti- 
septic treatment.  The  microscope,  and  the 
result  of  inoculation  into  guinea-pigs  of  a 
scrapmg  from  the  ulcer,  are  the  surest  means  of 
diagnosis. 

Cancrum  Oris 

This  is  an  acute  gangrenous  cellulitis  of 
the  cheeks  and  oral  tissues.  It  is  a  rare 
disease,  and  is  generally  seen  in  debilitated 
children,  but  sometimes  also  in  adults  (there 
appear  to  be  no  bacteriological  reports  of  these 
adidt  cases).  It  owns  the  same  infective 
pathology  as  cellulitis  of  the  neck,  having  its 
source  in  germ  stagnation  around  the  teeth, 
possibly  in  an  abscess  of  a  tooth ;  hence  it  is 
met  with  as  a  sequel  of  infective  fever  during 
the  course  of  which  the  mouth  has  not  been 
kept  clean.  The  disease  begins  commonly 
on  the  gums  or  inner  side  of  the  cheek  as  a 
livid  red  painful  induration,  or  may  be  first 
noticed  as  an  idcerated  patch.  As  it  spreads 
through  the  cheek  the  skin  becomes  red,  tense, 
and  shiny ;  and  later,  as  stasis  supervenes,  of  a 
pale  waxy  appearance  at  the  centre  surrounded 
by  a  red  oedematous  zone ;  later  still,  with  the 
onset  of  gangrene,  grejdsh  or  black  sloughs  are 
formed.  Unless  checked,  its  spread  is  con- 
tiiuious  in  all  directions,  till  death  ensues  from 
pneumonia,  or  general  blood-poisoning.  Tlie 
temperature  may  at  first  be  high,  104°  or 
105°  F.,  but  sinks  as  vitality  fails.  Pain  is 
variable,  sometimes  absent.  In  some  cases 
the  disease  recurs  after  apparent  cure.  The 
process  has  been  found  post  mortem  to  have 
spread  to  the  base  of  the  skull.  The  microbic 
cause  of  the  disease  is  said  to  be  a  slender 
bacillus  (?  leptothrix),  which  is  found  in  large 
numbers  at  the  advancing  edge,  and  probably 
lias  its  habitat  among  unclean  teeth,  making 
a  successful  invasion  when  general  resistance 
is  lowered.  It  has  not  been  cultivated,  but  is 
a  constant  and  predominant  organism  in  the 
diseased  tissues.  In  an  epidemic  following 
measles  it  was  found  in  the  similar  gangrene 
of  the  genital  region,  which  is  called  "  noma." 

Treatment  consists   in  thorough   removal   of 


739 


sloughs  and  infected  tissues  and  cleansing  with 
active  antiseptics.  1  in  500  perchloride  of 
mercury  is  recommended  by  Yates  and  E.  C. 
Kingsford  (1);  and  as  a  dressing,  lint  wrung 
out  in  1  in  1000  perchloride  of  mercury.  After 
removal  of  sloughs,  fuming  nitric  acid  may  be 
applied,  and  allowed  to  act  for  five  minutes 
before  being  washed  away.  This  is  followed 
by  antiseptic  dressings  and  provision  for 
drainage.  The  whole  mouth  should  be  well 
cleansed  at  the  time  of  operation.  The  patient 
.should  be  nursed  lying  in  the  prone  position, 
to  allow  discharge  to  flow  out  of  the  mouth. 
Cancrum  oris  can  only  be  cured  by  getting  bej'ond 
the  area  of  infection.  In  the  microscopic  ex- 
amination of  a  case  (1),  that  died  twenty -four 
houi'S  after  removal  of  sloughs,  the  tissues  were 
found  infected  for  a  distance  of  half  an  inch 
beyond  the  edge  of  the  lesion.  The  child  was 
too  ill  to  bear  any  severe  operation.  Probably 
at  least  a  quarter  of  an  inch  of  tissue  beyond 
the  slough  should  be  removed. 

IMMOBILITY  OF  THE  MANDIBLE 

Inflammatory  infiltration  of  the  neigh- 
bouring parts,  from  whatever  cause  arising, 
necessarily  imjJairs  the  mobility  of  the  mandi- 
bular joint.  The  commonest  of  such  conditions 
is  abscess  clue  to  a  third  lower  molar  already 
described  (Chajjter  II). 

Immobility  of  the  joints  not  infrequently 
follow  s  cancrum  oris  or  gangrene  of  the  soft  parts, 
e.  g.  follo\\  ing  ulcerative  stomatitis.  The  con- 
dition is  brought  about  by  cicatricial  contrac- 
tion of  soft  parts  during  healing.  Operations 
such  as  excision  of  the  scar,  forcible  stretching, 
division  of  the  scar,  are  in  themselves  u.seless. 
The  patient's  comfort  has  been  greatly  increased 
by  the  formation  of  a  false  joint  in  front  of  the 
scar,  the  jaw  being  divided  or  a  wedge-shaped 
piece  cut  out,  and  bony  union  prevented  by  free 


movement.  The  writer  has  obtained  complete 
success  by  simply  dividing  the  scar  and  there- 
after causing  the  patient  to  wear  a  mouth-prop 
continuously  for  the  first  two  or  three  months, 
later  at  night  only.  The  patient  wears  the 
prop  on  a  cord  secured  round  the  neck.  When 
no  mobility  can  be  restored,  teeth  may  be 
extracted  to  allow  more  ease  of  feeding.  Prob- 
ably a  more  important  point  is  to  extract  all 
the  teeth  or  all  but  the  front  teeth,  to  avoid 
the  inevitable  risks  of  oral  sepsis. 

The  mobility  of  the  mandibular  joint  may 
become  impaired  as  a  result  of  chronic  rheum- 
atoid arthritis :  any  degree  of  impau'ment  up 
to  complete  immobility  may  be  met  wdth ;  such 
cases  are  uncommon.  The  arthritic  changes 
may  themselves  have  been  a  result  of  chronic 
general  infection  from  septic  teeth.  In  a  few 
cases  destruction  of  the  joint  has  occurred, 
with  consequent  immobility,  as  a  result  of  the 
spread  of  septic  infection  from  a  dental  abscess, 
in  the  course  of  a  cellulitis,  or  from  an  ear 
lesion.  Excision  of  the  joint  may  give  reUef  in 
these  cases ;  resection  of  a  wedge-shaped  i^iece 
of  bone  has  also  afforded  good  results. 

Immobility  of  the  mandibular  joints  due  to 
tonic  muscular  spasm  is  an  early  and  almost 
constant  sign  of  tetamis.  It  is  generally  asso- 
ciated with  a  stiff  neck.  In  acute  cases  the 
general  muscular  spasms  leave  no  doubt  as  to 
the  diagnosis.  In  chronic  tetanus  also,  spasm 
of  other  groups  of  muscles,  espiecially  of  the 
face,  will  generally  be  found.  True  tetanus 
with  no  other  symptom  but  lockjaw  is  probably 
unknowai.  Tetanus  may  arise  as  an  infection 
through  mouth  ulceration. 

J.  G.  T. 

BIBLIOGRAPHY 

(1)  Yates  and  Kingsford,  E.G.     Lancet,  1899,  Vol.  I, 

p.  880. 

(2)  Edinb.  Med.  Jour. 

(3)  Medical  Record.     October,  1896. 


CHAPTEIi   L 


ODONTOSES 


An  Odontome  is  a  Tumour  derived  from  the 
Special  Cells  concerned  in  Tooth  Development. 
Sir  J.  Bland-Sutton  defined  an  Odontome  as 
"  a  tumour  composed  of  dental  tissues  in  varying 
proportions  and  different  degrees  of  develop- 
ment, arising  from  tooth-germs,  or  from  teeth 
still  in  the  process  of  growth". 

The  pathological  structures  arising  from 
embryological  dental  tissues  are  of  particular 
interest,  as  there  is  perhaps  no  tissue  in  the  body 
that  shows  such  a  series  of  gradations  between 
the  normal  and  the  abnormal.  So  difficult  is 
it  to  draw  the  line  between  the  two  that  it  may 
be  impossible  to  say  whether  a  particular 
specimen  is  merely  an  abnormally  developed 
tooth,  or  an  odontome.  The  consideration  of 
odontomes  is,  in  consequence,  rendered  particu- 
larly difficult.  The  gradation  between  the 
specimens  might  be  used  as  an  argument  in 
favour  of  classifying  calcified  masses  of  dental 
tissues  as  abnormal  teeth,  rather  than  true 
tumours.  But  if  the  particular  characteristics 
that  constitute  a  tumour  be  considered,  it  will  be 
found  that  in  many  cases  a  calcified  mass  of  den- 
tal ti.ssues  fulfils  the  necessary  demands  of  a 
tumour  :  it  reproduces,  more  or  less,  the  structure 
of  the  tissues  from  which  it  arises ;  it  tends  to 
grow  or  persist ;  it  has  no  function ;  has  no  par- 
ticular termination ;  and  is  a  new  formation. 
Pathologically,  the  relationship  between  an 
odontome  and  a  normal  tooth  may  be  said  to 
resemble  the  relationship  of  an  osteoma  to  normal 
bone. 

Formerly  the  term  Odontome  was  used  in  a 
clinical  sense  rather  than  a  pathological  one,  and 
was  applied  to  calcified  masses  alone.  It  was 
sho^ni  by  Broca  (8)  that  this  conception,  that 
an  odontome  exists  only  as  a  calcified  mass,  is  too 
narrow  a  view,  and  that  uncaleificd  dental  tissues 
can  exist  as  tumours.  Sir  J.  Bland-Sutton  in- 
cluded two  cystic  tumours  in  his  classification. 
One,  called  by  him  an  Epithehal  Odontome,  is 
free  from  any  calcified  dental  tissue ;  whilst 
the  other,  Dentigerous  Cyst  (called  by  him 
Follicular  Odontome),  is  uncalcified  in  the  part 
that  constitutes  the  true  tumour  or  cyst,  but 
contains  a  tooth  that  is  more  or  less  completely 
formed. 

Li  dealing  with  the  .subject  of  odontomes,  the 
work  of  Sir  J.  Bland-Sutton  must  be  taken  as  a 
basis  upon  which  to  work.     His  definition  and 


from  the  tooth- 
follicle. 


classification  are  those  most  widely  accepted. 
A  literal  interpretation  of  his  definition,  as 
expressed  in  the  shorter  one  at  the  commence- 
ment of  this  article,  must  \viden  the  classifica- 
tion to  include  all  tumours  and  cysts  that  are 
I  derived  from  the  tooth-germs  or  special  cells 
concerned  in  tooth  development. 

The  following  classification  by  Sir  J.  Bland- 
Sutton  (6),  most  recently  published,  is  a  modi- 
fication of  that  put  forward  by  him  in  his 
original  paper  (4). 

I       1.  Epithelial    Odontoma — from   the   enamel- 
organ. 

2.  Folhcular  Odontoma    ] 

3.  Fibrous  Odontoma 

4.  Cementoma 

5.  Compound  Follicular 

Odontoma  I 

6.  Radicular  Odontoma — from  the  pajjiUa. 

7.  Composite    Odontoma — from    the    whole 

germ. 

Certain  groups  of  specimens,  which  do  not 
come  under  the  headings  in  this  classification, 
must  be  added,  as  they  fulfil  the  conditions 
expressed  in  the  definition.  The  particular 
groups  added  will  be  indicated  in  the  description 
of  the  respective  types.  Sir  Frederic  Eve  (11) 
has  described  odontomes  of  a  malignant  char- 
acter, ^\hich  will  need  to  be  included  should  their 
existence  become  definitely  estabhshed.  The 
classification  given  below  has  been  recently  put 
forward,  and  is  based  upon  the  method  originally 
used  by  Sir  J.  Bland-Sutton,  who  endeavoured 
to  base  a  classification  upon  aberrations  occurring 
in  what  might  be  called  primary  dental  tissues, 
viz.  the  enamel-organ,  the  papilla,  the  follicle, 
or  the  whole  tooth-germ  ;  he  added  a  fifth  group, 
"  Anomalous  ".  His  more  recent  classification 
would  appear  to  be  based  upon  the  particular 
tissues  of  the  tooth-germ  that  are  involved, 
rather  than  the  tissue  that  was  primarily  in 
error,  as  was  imphed  in  the  earlier  classification. 
The  Committee  of  the  British  Dental  Associ- 
ation (7)  divided  odontomes  into  three  main 
groups — 

I. — Epithelial  Odontomes, 

where    the    abnormal    development    occurs    in 
the  dental  epithelium  alone. 


740 


741 


II. — Composite  Odontomes, 

where  the  abnormal  development  occurs  pri- 
marily in  the  dental  epithelium,  and  secondarily 
in  the  dental  papilla,  and  may  occur  in  the 
follicle  also. 

III. — Connective  Tissue  Odontomes, 
where  the  abnormal  development  occurs  only 
in  the  dental  tissues  of  mesodermic  origin. 

In  the  first  two  groups  the  terms  Epithelial 
Odontome  and  Composite  Odontome  are  used 
in  a  wider  sense  than  in  fSir  .J.  Bland-Sutton's 
classification.  Epithelial  odontomes  include 
all  tumours  and  cysts  arising  from  the  dental 
epithehum  alone.  Composite  odontomes  in- 
clude all  those  ari.sing  from  the  dental 
epithelium,  dentine  papilla,  and  commonly 
the  tooth-follicle  (the  whole  tooth-germ).  It  is 
necessary  to  remember  that  the  development 
of  dentine  is  dependent  upon  the  enamel-organ, 
although  enamel  may  not  be  developed,  and  in 
consequence  groups  both  I  and  II  of  this  classifi- 
cation would  have  to  be  placed  under  the 
heading  "  Aberrations  of  the  Enamel-Organ  " 
of  the  older  classification. 

The  third  group,  comprising  the  odontomes 
that  are  unaffected  by  the  enamel-organ,  have 
been  called  connective  ti.ssue  odontomes. 

Each  of  the  three  divisions  has  been  sub- 
divided in  order  to  classify  as  far  as  possible 
the  various  types  of  odontomes  that  can  be 
recognized. 

Group  I  contains  tumours  that  are  not 
calcified,  whilst  practically  all  are  calcified  in 
Group  II.  Group  III  contains  both  calcified 
and  uncalcified  specimens. 

CLASSIFICATION   OF   ODONTOMES 

I.— EPITHELIAL    ODONTOMES, 

where  the  aljnormal  development  takes  place  in 
the  dental  epithelium  alone. 

Multilocular  Cysts. 

Dentigerous  Cysts. 

Dental  Cysts. 

(Carcinomatous  Odontomes.) 

II.— COMPOSITE   ODONTOMES, 

where  the  abnormal  development  takes  place 
primarily  in  the  dental  epithehum,  and  secon- 
darily in  the  dental  papilla,  and  may  occur  in 
the  follicle  also. 

(1)  Where  the  abnormal  developnu^nt  of  the 
dental  epithelium  is  such  that  the  for- 
mation of  numerous  irregular  dentine 
papillae  results,  and  these  become 
calcified. 

Complex  Composite  Odontomes. 

Compound  Composite  Odontomes. 


(2)  Where  the  abnormal  development  of  the 

dental  epithelium  is  such  that  the 
formation  of  t%\o  or  more  tooth-hke 
dentine  papillae  results,  and  these  are 
calcified  as  one  mass. 

Geminated  Composite  Odontomes. 

Gestant  Composite  Odontomes. 

Enamel  Nodules. 

(3)  Wliere    the    abnormal    development    of 

the  dental  epithelium  is  such  that  the 
formation  of  a  dilated  portion  of  the 
dentine    papilla    results,    and    this    is 
calcified  as  one  mass. 
Dilated  Composite  Odontomes. 

III.— CONNECTIVE   TISSUE   ODONTOMES, 

where  the  abnormal  development  takes  place 
only  in  the  dental  tissues  of  mesodermic  origin. 

Fibrous  Odontomes. 
Cementomes. 
(Sarcomatous  Odontomes.) 

In  order  to  understand  odontomes,  it  is  neces- 
sary to  have  an  accurate  knowledge  of  the 
development  of  the  teeth,  and  although  it  is 
impossible  to  give  any  detailed  description 
here,  one  or  two  points  need  to  be  mentioned. 
The  first  stage  in  the  development  of  the  teeth 
consists  in  the  formation  of  what  may  be  called 
a  "  dental  epithelium  "  ;  this  tissue  is  derived 
from  the  deeper  cells  of  the  superficial  epithelium, 
which  undergo  proliferation,  forming  a  suc- 
cession of  epithelial  structures  entirely  concerned 
with  tooth  development.  They  are  described 
as  growing  in  such  a  manner  as  to  "  dip  into  " 
the  neighbouring  tissues;  and,  in  fact,  it  is 
implied  that  they  force  their  way  dowTi  into 
the  structures  lying  below  them.  It  would  be 
more  correct  to  describe  the  growth  of  these 
cells  as  occurring  concomitantly  with  the  neigh- 
bouring structures,  the  latter  enfolding  the 
former,  which  thus  become  deeply  situated. 
The  dental  epithelium  exists  at  first  as  the  tooth- 
band  ;  enamel -organs  are  developed  in  connec- 
tion with  it ;  later  the  tooth-band  ceases  to 
exist  as  a  uniform  layer,  but  becomes  a  series 
of  epithelial  columns  or  connecting  bridges, 
as  described  by  Rose  (21).  The  enamel-organs 
give  rise  to  the  enamel  of  the  teeth,  and  also 
determine  the  presence  and  form  of  the  dentine  ; 
the  latter  influence  is  brought  about  by  the 
epithelial  cells  of  the  deepest  portion  of  the 
enamel-organ,  which  extend,  as  the  sheath  of 
Hertwig  (15),  to  the  farthest  limit  of  dentine 
formation,  viz.  the  apex  of  the  tooth.  The  dental 
epithelium  is  said  to  disappear  after  the  cessa- 
tion of  its  functions.  The  last  function  attri- 
buted to  it  is  determining  the  final  position  of 
the  tooth  in  the  process  of  eruption  (16).  As 
far  as  is  known  therefore  at  present,  there  should 


742 


not  be  any  dental  epithelium  in  the  tissues  after 
complete  eruption,  and  if  it  occurs  it  should  be 
regarded  as  pathological.  The  presence,  at  a 
later  period  than  this,  of  small  collections  of 
cells  derived  from  the  dental  epithelium  has 
been  demonstrated  by  numerous  observers  ;  but 
no  significance  is  attributed  to  them,  except 
that  of  a  pathological  nature.  The  epithelial 
remnants  were  found  by  Malassez  (18)  (19)  in  a 
very  large  proportion  of  the  specimens  examined 
by  him.  He  found  collections  of  cells,  even  in 
the  form  of  a  network,  about  the  roots  of  the 
teeth  ;  they  were  situated,  for  the  most  part,  on 
the  inner  (near  tlie  tooth)  aspect  of  tlie  peri- 
odontal membrane  ;  farmore  rarely  they  occurred 
elsewhere,  occasionally  in  the  outer  part  of  the 
periodontal  membrane,  and  even  in  the  alveolar 
spaces  of  the  bone. 

Details  of  the  development  of  other  parts  of 
the  tooth  are  unnecessary.  The  dentine  papilla 
is  dependent  upon  the  presence  of  an  enamel- 
organ  and  apparently  never  forms  independently. 
The  enamel-organ  forms  an  epithelial  cap.  and 
the  subjacent  tissues  enclosed  within  it  undergo 
changes  to  form  the  dentine  papilla. 

There  does  not  appear  to  be  any  evidence 
to  show  that  any  one  fully  formed  dental  tissue 
is  ever  produced  alone — a  fact  of  great  signifi- 
cance in  connection  with  the  present  subject. 

I.— EPITHELIAL    ODONTOMES 

This  group  comprises  those  odontomes  in 
which  the  abnormal  development  occurs  in  the 
dental  epithelium  alone. 

The  term  Epithelial  Odontome  was  intro- 
duced by  Sir  J.  Bland-Sutton  and  was  used  by 
him  for  the  group  here  described  as  Multi- 
locular  Cysts,  a  name  which  has  been  applied 
to  them  for  a  long  time.  Sir  Frederic  Eve  has 
employed  the  term  epithelial  odontome  in  a 
wider  sense,  using  it  for  two  tumours  "  derived 
from  enamel-organ  cells  : 

(a)  Epithelial  Odontome  (cystic  variety) 
or  Cystic  Epithelial  Tumour  (Multi- 
locular  Cysts  of  the  present  classifica- 
tion). 

{h)  Epithelial  Odontome  (carcinoma),  usually 
described  as  spheroidal-  or  columnar- 
celled  carcinoma." 

Malassez  not  only  recognized  the  origin  of  the 
nuiltilocular  cystic  tumour  from  tlio  dental 
epithelium,  but  also  that  both  dental  and 
dcntigerous  cysts  are  derived  from  the  same 
tissue.  The  work  of  Malassez  has  been  corro- 
borated. Three  types  of  odontomes,  therefore, 
can  be  described  under  the  heading  Epithelial 
Odontomes  (with  a  fourth  if  Carcinomatous 
Odontomes  be  accepted). 


1.  Multilocular  Cysts. 

2.  Dentigerous  Cysts. 

3.  Dental  Cysts. 
(Carcinomatous  Odontomes.) 

1.  Multilocular  Cysts 

A  Multilocular  Cyst  is  an  innocent  tumour 
arising  from  the  dental  epithelium,  with  the 
formation  of  numerous  cystic  cavities.  Many 
names  have  been  given  to  these  tumours  ;  the  one 
used  here  has  been  most  commonly  employed. 

Fibro-cystic  disease  of  the  jaw  was  another 
name  frequently  used,  and  the  description  of 
cases  and  specimens  under  this  and  other 
names,  such  as  cystic  sarcoma  and  cystic 
epithelioma,  may  lead  one  to  think  that  there 
are  varying  types,  many  of  which  are  malignant. 
Sir  J.  Bland-Sutton  believes  that  several  of  the 
tumours  formerly  described  under  these  different 
names  were  endotheliomata. 

It  would  appear  that  the  multilocular  cystic 
character  does  not  exist  in  the  carcinomatous 
tumours  derived  from  the  dental  epithelium, 
but  that  it  may  be  associated  with  a  sarcomatous 
development.  At  present  the  knowledge  of  the 
malignant  tumours  originating  in  embryonic 
dental  tissues  depends  almost  entirely  upon  the 
work  of  one  observer.  Sir  Frederic  Eve. 

Multilocidar  cysts  were  investigated  by  Sir 
Frederic  Eve  (10),  who  called  them  multilocular 
cystic  epithelial  tumours ;  he  came  to  the  con- 
clusion that  they  originate  by  an  ingrowth  of 
the  epithelium  of  the  gums.  In  his  description 
of  the  structure  of  the  tumours  he  points  out  the 
resemblance  to  the  cells  of  the  enamel -organ, 
and  therefore  would  seem  to  imply  that  the 
ingrowth  may  be  compared  with  the  original 
formation  of  the  dental  epithelium.  Eve  cer- 
tainly recognized  the  epithelial  nature  of  the 
tumours,  although  more  recent  observations 
tend  to  disprove  the  view  that  they  are  derived 
directly  from  the  superficial  epithelium. 

Malassez,  discovering  epithelial  remnants — 
"  debris  epitheUaux  paradentaires  " — in  con- 
nection with  the  teeth,  attributed  the  origin  to 
these  cells. 

From  the  resemblance  of  certain  parts  of 
these  tumours  to  an  enamel-organ,  it  has  been 
thought  that  they  originate  from  an  enamel- 
organ.  Falkson  (12)  (13)  was  the  first  to  advance 
this  view  as  the  result  of  the  examination  of  one 
specimen  ;  the  illustrations  to  his  paper  certainly 
show  a  close  resemblance  to  an  enamel-organ. 

Sir  J.  Bland-Sutton  also  gives  the  enamel- 
organ  as  the  site  of  origin  of  these  tumours, 
and  it  is  probably  the  view  most  widely  accepted 
at  the  present  time.  The  chief  difficulty  in 
accepting  this  view  is  the  age  at  wliich  the 
tumours  arise.  The  enamel-organs  undergo 
marked  changes  at  an  early  date,  with  the 
production  of  dentine  and  enamel,  and  as  no 


743 


calcified  dental  tissue  is  found  in  these  tumours, 
they  must  either  arise  at  a  period  prior  to 
dentine  and  enamel  formation,  or  else  changes 
occur  in  the  enamel-organ  preventing  normal 
development,  the  pathological  significance  of 
which  is  not  demonstrable  until  later  in  the  life 
of  the  individual. 


for  the  point  to  have  been  decided.  One  case  (8) 
of  considerable  interest  occurred  in  a  child  aged 
4.V  years ;  all  the  deciduous  teeth  were  free  from 
caries,  and  a  radiograph  taken  after  the  removal 
of  the  tumour  indicated  the  absence  of  a  per- 
manent incisor. 

Falkson    suggested    that    only    part    of    the 


Fia.  903. — Miiltilocular  cyst.  (Museum  of  the  linijiu  i  on:  yi  oi  Suryeuns  oj  Emjland.  The  tumour  was  almost  intact 
but  by  the  courtesy  oj  the  Curator  a  section  was  made  to  demonstrate  its  nature.) 

Tlie  following  i.s  the  account  given  in  the  catalogue — 

Tlie  right  lialf  of  a  lower  jaw,  witli  a  portion  of  its  left  side,  including  the  left  incisor  teeth,  removed  by  operation. 
A  inultilocular  cystic  tiuuour,  developed  in  the  interior  of  tlie  bone,  extends  from  tlie  middle  of  the 
ascending  ramus  to  the  right  incisor  tooth.  It  is  of  an  elongated  oval  form,  and  projects  equally  on  both 
sides  of  the  jaw  and  into  the  mouth.  It  has  removed  in  the  progress  of  its  growth  all  the  molar  and  the 
second  premolar  teeth,  and  has  expanded  and  in  some  situations  perforated  the  walls  of  the  jaw.  In  these 
situations  it  is  covered  by  the  distended  periosteum.  An  opening  has  been  made  into  a  cyst,  in  front  of  the 
coronoid  process,  exposing  its  interior,  which  is  only  partly  filled  with  the  morbid  growth. 

The  patient  was  a  woman  aged  50.  Tlio  (hsease  had  been  observed  for  a  year,  and  had  produced  intense  pain. 
She  died  a  month  after  the  ojieration,  with  pleuritic  effusion.      (From  the  Museum  of  Robert  Liston.) 


The  absence  of  a  tooth  from  the  series  (except 
in  the  case  of  a  supernumerary  enamel-organ)  is 
said  to  l)e  necessary  if  the  enamel-organ  gives 
rise  to  the  tumour,  but  this  statement  is  made 
upon  insufficient  evidence;  the  majority  of  the 
recorded  eases  are  certainly  of  no  value  for 
the  determination  of  this  point.  It  might  be 
expected  that  the  absence  of  a  tooth  from  the 
series,  and  tlie  subsequent  development  of  the 
tumour,  would  be  associated  sufficiently  often 


enamel-organ  may  be  involved  in  the  production 
of  the  tumour.  It  must  be  remembered  that 
the  term  "enamel-organ  ""  is  sometimes  widely 
used  to  include  all  the  dental  epithelium. 

The  connection  of  the  epithelium  of  the 
tumour  with  the  superficial  epithelium,  such 
as  is  fixMjuently  seen,  would  suggest  that  the 
epithelium  connecting  the  enamel-organ  with. 
the  surface  also  plays  a  part  in  the  tumour 
formation. 


744 


Local  irritation  has  been  thought  to  be  a 
factor  in  causing  the  growth  of  the  tumour ;  in 
one  case  the  tumour  developed  after  fracture  of 
the  jaw.  A  history  of  injury  has  been  obtained 
in  other  cases,  and  local  inflammation  and  dental 
caries  are  cited  as  possible  causes.  The  evidence 
is  not  conclusive  even  in  those  cases  where  pre- 
vious irritation  was  kno\\ii  to  exist. 

A  large  number  of  multilocular  cysts  have 
been  described,  and  specimens  are  to  be  found 
in  most  pathological  museums.  In  the  majority 
of  cases  the  tumours  had  attained  a  considerable 
size,  involving  a  large  part  of  the  jaw  and 
necessitating  the  removal  of  half  or  more  of  the 
mandible,  or  one  of  the  maxillae. 

The  portion  of  jaw  removed  usually  presents 
a  distended  appearance,  containing  a  lobulated 
mass,  which  projects  from  the  alveolar  border. 
The  lobules  if  marked  are  unequal,  one  or  two 
being  quite  large,  wliilst  numerous  smaller 
ones  may  be  noticeable.  If  the  growth  of  the 
tumour  has  not  advanced  so  far  as  to  show  a 
lobulated  appearance,  the  outline  will  be  of  an 
oval  or  globular  nature.  The  outer  alveolar 
plate  is  generally  more  aifected  than  the  iiuier ; 
a  thin  layer  of  bone  covered  by  periosteum  may 
still  be  present  over  the  whole  or  the  larger  part 
of  the  tumour,  although  deficiencies  may  be 
detected  if  the  cysts  are  large,  when  the  cystic 
character  of  the  lobule  can  be  recognized  by  the 
presence  of  fluctuation. 

The  body  of  the  mandible  is  involved  in  large 
growths,  but  it  is  much  less  affected  than  the 
alveolar  process,  as  one  would  expect  from  the 
seat  of  origin  of  the  tumour.  In  the  maxilla 
the  maxillary  sinus  is  nearly  always  involved. 

The  teeth  may  still  be  present,  the  roots  may 
show  marked  absorption,  or  be  projecting  into 
a  cystic  cavity ;  usually  they  faU  out  or  have 
been  removed. 

Openings  may  be  seen  into  a  cystic  cavity, 
generally  at  a  point  where  a  tooth  has  been 
lost,  or  ulceration  and  sloughing  may  have 
resulted  from  injury,  which  is  usually  caused  by 
a  tooth  of  the  opposing  jaw. 

The  thinned-out  tissue  over  the  cyst  gives  a 
peculiar  sensation  when  pressed  upon,  which 
appears  to  be  characteristic  of  this  condition ; 
it  might  be  said  to  feel  like  thick  rubber,  or  as 
if  the  bone  were  decalcified. 

If  a  section  be  made  of  the  growth,  it  will  be 
found  to  contain  numerous  cavities  containing 
a  viscid  fluid  of  a  brownish  colour  (or  sometimes 
white),  and  glutinous  or  colloid.  The  cystic 
cavities  vary  very  much  in  size  ;  the  largest  may 
measure  an  inch  or  more  across,  whilst  smaller 
ones  are  seen  grading  to  minute  cells,  which  are 
only  just  visilile  to  the  naked  eye.  Occasionally 
a  type  is  seen  where  all  the  cysts  are  small  and 
uniform  in  size,  presenting  a  honeycomb  appear- 
ance. 


The  cystic  cavities  present  a  smooth  lining 
or  a  soft  membranous  surface  with  papillary 
projections ;  or  a  lobule  of  a  neighbouring  cyst 
may  cause  a  bulging  inwards  of  the  w'all.  The 
cyst-wall  may  be  incomplete  where  a  communi- 
cation with  a  neighbouring  cyst  occurs  through 
a  rounded  opening. 

The  smaller  lobules  may  present  solid  con- 
tents connected  with  the  whole  wall,  or  a  more 
or  less  pedunculated  mass  filHng  the  cavity. 

In  an  early  stage,  the  cystic  character  may  be 
almost  unrecognizable  to  the  naked  eye,  papil- 
lary projections  into  the  cavities  rendering  the 
tumour  almost  soUd. 

Where  the  tumour  is  encroaching  upon  the 
neighbouring  bone  it  consists  of  a  reddish, 
friable  substance. 


Fig.  964. — Multilocular  cyst.  {Museum  of  the  Royal 
College  of  Surgeons  of  England.)  This  specimen 
shows  the  "  honeycomb "  variety,  where  the 
cystic  cavities  are  more  uniform  in  size  than  in 
the  more  common  type.  Clinically  this  tumour 
would  not  show  the  lobulated  appearance  so 
distinctly  as  the  type  containing  large  cysts, 
although  the  surface  would  not  be  so  definitely 
rounded  as  in  a  dentigerous  or  dental  cyst. 

The  septa  between  the  cysts  vary  considerably 
in  thickness  ;  they  may  be  perforated  where  the 
cysts  are  large.  They  appear  to  consist  of  the 
soft  lining  membranes  of  the  cysts  with  a  vari- 
able amount  of  fibrous  tissue  between  them, 
and  perhaps  some  bone,  which  may  be  a  part  of 
the  bone  of  the  jaw,  or  of  new  formation.  The 
bone  changes  are  well  shown  in  macerated 
specimens ;  in  some  cases  it  will  be  seen  that  a 
great  destruction  of  this  tissue  has  taken  place 
and  that  new  bone  must  have  been  formed. 
The  distortion  may  be  so  considerable  that  the 
original  form  is  quite  unrecognizable. 

In  the  early  conditions  of  multilocular  cysts, 
when  the  tumours  are  small,  a  definite  adventi- 
tious capsule  is  found  to  enclose  the  whole 
tumour.  A  capsule  cannot  be  so  readily 
demonstrated  when  the  tumour  is  large  and 
has  extended  so  as  to  involve  the  neighbouring 
structures.  The  periosteum  forms  a  capsule 
w  hen  the  bone  has  been  destroyed  ;  at  first  new 


745 


bone  is  formed  by  the  periosteum,  l)ut  witli  the 
increase  in  size  of  the  tumour  the  bony  wall 
becomes  more  and  more  imperfect.  At  an 
early  stage  the  tumour  can  be  shelled  out  with 
its  fibrous  capsule  ;  later  this  is  not  possible. 

The  microscopical  characters  vary  considerably 
in  different  tumours  and  in  different  parts  of  tbe 
same  tumour. 

The  cysts  u.sually  possess  a  lining  of  Hattened 
or  spheroidal  cells,  which  may  be  only  one  cell 
deep  in  large  cysts.  It  is  stated  that  large  cysts 
may  not  have  a  cellular  lining ;  this  may  be  so, 
but  the  possibility  of  their  being  lost  in  pre- 
paration of  the  sections  must  be  remembered. 
Small  cysts  usually  have  several  layers  of  cells 
with  the  more  central  ones  undergoing  degenera- 
tion. The  smaller  cysts  may  give  an  alveolar 
appearance  to  the  section,  particularly  when  the 
central  cells  have  degenerated  and  been  lost  in 
preparation. 

Cells  undergoing  proUferation  and  forming 
projections  into  cj^stic  cavities  can  be  seen,  and 
occasionally  they  may  be  observed  covering 
dilated  blood  capillaries.  Columns  of  epithelial 
cells  are  present  where  the  tumour  is  growing, 
and  also  beneath  the  epithelium  of  the  gum  ; 
a  definite  comiection  is  commoidy  present,  by 
means  of  these  columns,  between  the  epithe- 
lium of  the  tumour  and  that  of  the  surface. 

The  cells  undergoing  proliferation  are  usually 
small,  but  larger  and  distended  \\hen  degenerat- 
ing. The  nature  of  the  gro\^•t'l^  of  the  tumour  is 
rendered  obvious  by  microscopical  examination. 
Li  the  cysts  the  degenerating  cells  form  the  fluid 
contents,  whilst  the  marginal  cells  proliferate. 
At  the  growing  edge  of  the  whole  tumour 
epithelial  masses  are  produced,  wliich  undergo 
degeneration  at  points,  producing  new  cj'sts. 

Cells  of  a  columnar  character  are  seen,  and  in 
some  tumours  to  a  considerable  extent,  as  in 
Falkson's  case ;  they  are  said  to  resemble  the 
columnar  cells  of  the  enamel-organ.  The 
degeneration  of  the  cells  may  also  occur  in  such 
a  manner  as  to  produce  an  arrangement  resem- 
bling the  stellate  reticulum  or  enamel -pulp  of 
the  enamel-organ.  The  cells  are  for  the  most 
part  of  the  spheroidal  type,  and  similar  to  those 
that  constitute  the  greater  part  of  the  dental 
epithelium. 

Multilocular  cysts  occur  more  frequently  in 
the  mandilile  tlian  in  the  maxilla  ;  the  proportion 
given  by  Bernays  (3)  is  11  to  1,  but  it  appears 
from  tlie  record  of  cases  to  be  greater  than  this. 
The  proportion  of  men  to  women  is  about  1  to 
2.  There  does  not  appear  to  be  any  explanation 
of  the  greater  frequency  of  the  condition  in 
women,  nor  of  its  far  commoner  occurrence  in 
tlie  mandible. 

The  ag(^  at  which  the  tumour  appears  varies 
very  considerably ;  the  earliest  recorded  case 
was  in  a  child  of  six  months,  and  the  latest  in 
24* 


a  man  of  seventy-five  years.  About  half  the 
patients  in  the  cases  recorded  were  between  the 
ages  of  twenty -one  and  thirty-five  years.  It  is 
necessary  to  remember  that  eases  do  not  come 
under  observation  at  an  early  period ;  this  is 
probably  due  to  the  slow  growtli  of  the  tumour, 
and  the  absence  of  symptoms  that  cause  dis- 
comfort to  the  patient.  It  is  frequently  im- 
possible to  ascertain  with  any  accuracy  the 
length  of  time  the  growth  has  been  present. 

The  clinical  aspects  of  the  tumour  vary  \^ith 
the  length  of  time  it  has  been  present. 

The  patient  complains  of  a  swelling,  usually 
in  the  molar  region  of  the  mandible,  which  has 
been  very  slowly  increasing  in  size.  There  is 
no  pain  or  discomfort.  The  alveolar  border  of 
the  jaw  is  found  to  be  enlarged,  the  outer  alveolar 
plate  being  more  affected  than  the  inner  one. 
The  mucous  membrane  does  not  present  any 
change  in  appearance. 

On  examination  a  softened  point  may  be  dis- 
covered and  fluctuation  may  be  obtained. 

When  the  tumour  is  larger  it  may  possess  a 
lobulated  surface  with  thinning  of  the  bone, 
and  points  where  fluctuation  is  present,  parti- 
cularly over  the  large  lobules. 

Wliere  the  bone  is  thin  "  parchment  crack- 
ling "  can  be  obtained,  or  the  elastic  sensation 
already  referred  to  may  be  felt,  the  tissues 
yielding  to  pressure  as  if  composed  of  thick 
rubber  or  decalcified  bone. 

If  an  opening  into  a  cystic  cavity  exists,  a 
fluid  di.scharge  is  seen,  wliich  is  usually  viscid 
and  of  a  brownish  colour. 

With  the  increase  in  size  of  the  growth  the 
patient  may  complain  of  difficulty  in  swallowing, 
of  mastication,  or  even  of  respiration.  The 
hypersecretion  of  sabva  may  be  a  distressing 
symptom,  whilst  pain  may  result  from  ulcera- 
tion due  to  injury  bj^  an  opposing  tooth. 

Infection  may  occur,  usually  as  the  result  of 
injury  or  following  an  incision  that  is  made 
owing  to  an  error  in  diagnosis.  When  suppura- 
tion occurs  the  nature  of  the  tumour  may  be 
obscured.  It  would  seem  that  infection  of 
these  tumours  docs  not  readily  occur. 

The  diagnosis  from  dentigerous  and  dental 
cysts  is  very  difficult  at  an  early  stage  and  may 
be  impossible.  Later  the  condition  is  usually 
characteristic,  and  not  likely  to  be  mistaken. 

Treatment. — The  treatment  consists  in  com- 
plete removal  of  the  grow  th.  It  should  be  removed 
in  its  capsule,  but  this  may  be  impossible  when 
the  tumour  has  attained  to  a  considerable  size. 
Jt  may  be  necessary  to  remove  the  surroiuiding 
tissues  w  ith  the  growth,  even  to  the  extent  of  ex- 
cision of  part  of  the  jaw.  Removal  of  the  tumour 
and  scraping  the  neighbouring  ti.ssucs  i.s  advo- 
cated, l>ut  does  not  appear  to  be  very  satisfactorJ^ 

Should  any  portion  of  the  tumour  be  left  it 
will  continue  to  grow,  and  a  further  operation 


746 


will  be  necessary  ;  deeper  structures,  such  as  the 
nasal  cavity  or  orbit,  may  be  involved  in  cases 
occurring  in  the  maxilla. 

2.  Dentigerous  Cysts 

A  Dentigerous  Cyst  is  an  innocent  tumour 
due  to  proliferation  and  degeneration  of  cells 
of  the  enamel-organ  or  tooth-band  connected 
w-ith  an  unerupted  tooth,  which  is  partially  or 
completely  developed. 

Dentigerous  cysts  have  been  recognized  and 
have  attracted  a  peculiar  interest  as  cystic 
tumours  of  the  jaws  for  a  long  period.  The 
particular  interest  attached  to  them  is  probably 
dependent  upon  the  presence  of  a  tooth  witliin 
the  cyst. 

These  cysts  were  classified  by  Sir  J.  Bland- 
Sutton  as' due  to  an  aberration  of  the  follicle 
of  the  tooth -germ,  and  were  named  by  him 
Follicular  Odontomes.  As  it  is  now  kno-\\ii 
that  the  follicle  does  not  play  any  part  in  the 
develoj)ment  of  the  tumour,  it  is  advisable  to 
return  to  the  former  name  of  dentigerous  cyst 
(tooth-bearing  cyst). 

Recognition  of  the  epithehal  origin  of  these 
cysts  is  due  to  Malassez  (18)  (19),  but  only 
within  recent  years  has  this  view  been  definitely 
established. 

It  was  pointed  out  l)y  C.  Tomes  (24)  that  a 
small  collection  of  fluid  is  not  infrequently  found 
over  an  erupting  tooth,  between  the  enamel  and 
the  tootli-capsule.  He  argues  that  the  cyst 
is  obhterated  by  the  advancing  tooth,  or  the 
fluid  escapes  by  perforation  of  the  overlying 
gum  ;  but  when  the  tooth  is  deeply  situated  in 
the  jaw  a  cy.stic  tumour  may  be  the  result. 
Tomes  compared  a  dentigerous  cyst  with  an 
eruption  cyst,  and  his  view  that  they  are  of  the 
same  nature  would  seem  to  be  correct. 

The  line  of  demarcation  between  the  eruj^tion 
cyst  of  Tomes  and  a  dentigerous  cyst  may  be 
illustrated  Ijy  the  case  of  a  boy  aged  about  8i 
vears.  The  right  central  incisor  was  partially 
erupted  but  displaced  to  the  right :  a  small 
fluctuating  swelling  was  present  in  the  position 
of  the  left  central  incisor.  It  was  thought  to  be 
a  large  eruption  cyst  of  Tomes.  A  radiograph 
was  taken  showing  the  left  central  incisor  to  be 
high  up,  and  lying  horizontally  in  the  substance 
of  the  bone  with  the  crown  directed  forwards. 
When  opened  the  cystic  cavity  was  found  to 
be  about  the  size  of  a  small  filbert ;  the  tooth  was 
removed,  and  found  to  be  quite  normal  although 
incomplete. 

It  has  been  sliown  tliat  an  erupting  tooth  has 
a  cap  of  epithelial  ceils  overlying  it,  wliich  are 
comiected  with  the  gingival  epithelium  by  a 
column  or  columns  of  cells.  The  cells  of  the 
epithelial  cap  are  derived  from  those  that 
formed  the  external  epithelium  of  the  enamel - 
organ,  whilst  the  connecting  bridges  originated 


in  the  tooth-band.  These  cells  undergo  proli- 
feration and  degeneration,  and  it  has  been  sug- 
gested (16)  that  they  are  concerned  in  the  process 
of  eruption,  and  probably  determine  the  final 
position  of  the  tooth  on  the  gingival  ridge. 

A  dentigerous  cyst  is  now  kno\ni  to  be  due  to 
proliferation  and  degeneration  of  epithehal  cells, 
and  it  would  appear  to  be  almost  certain  that 
these  are  derived  either  from  the  epithelial  cap, 
or  in  some  cases  from  the  cells  of  the  tooth-band. 


Fig.  9(55. — Kadiograph  of  jaw  showing  a  dentigerous 
cyst  in  the  right  side  of  the  mandible  associated 
witli  the  second  premolar.  From  a  boy  aged 
six  years  and  nine  months. 

These  cysts  usually  appear  at  a  later  date  than  the 
period  of  normal  eruption.  This  case  is  unusual, 
in  that  it  is  early  for  a  dentigerous  cyst,  and 
particularly  so  for  the  tooth  involved.  At  the 
operation  the  bulging  outer  alveolar  plate  was 
cut  away,  and  the  lining  of  the  bony  cavity 
was  removed  intact,  except  where  the  tooth  was 
situated,  the  latter  being  extracted  afterwards. 

Malassez  stated  that  dentigerous  cysts  pos- 
sessed an  epithelial  lining,  and  that  the  cells 
were  derived  from  epithehal  remnants  of  the 
enamel -organ. 

It  has  been  suggested  that  the  cyst  results 
from  an  unsuccessful  attempt  at  eruption  ;  it 
is  true  that  the  teeth  in  dentigerous  cysts  are 
often  misplaced,  usually  to  a  marked  degree ; 
on  the  other  hand,  many  teeth  fail  to  erupt,  but 
do  not  give  rise  to  dentigerous  cysts.  It  must 
be  remembered  that  the  cystic  development 
may  displace  the  tooth. 

Albcrran  (1),  who  recognized  the  presence  of 


747 


an  epithelial  lining,  thought  these  cysts  resulted 
from  difficulty  in  eruption ;  he  thought  the 
"iter  dentis  "  was  responsible  for  the  direction 
in  which  the  tooth  would  erupt,  and  that  in 
these  cases  the  canal  ^^•as  obstructed  in  some 
manner,  so  that  the  tooth 

failed  to  reach  the  surface.  ''    ~ 

It  is  of  interest  that  the 
cysts  occur  about  the 
period  of  eruption,  and  the 
teeth  most  commonly  in- 
volved correspond  with 
those  that  most  frequenth 
fail  to  erupt,  or  erupt 
abnormally.  The  time  dl 
the  appearance  of  the  cy.st  - 
is  usually  rather  later  than 
the  date  of  normal  erupt  ion 
of  the  particular  tooth  in- 
volved. Among  recorded 
cases  the  greatest  age  was 
in  a  patient  of  tlrirty-five 
years,  when  the  cyst  was 
connected  wth  a  third 
mandibular  molar ;  other  cases  in  comiectiou 
^nth  this  tooth  occurred  at  thirty  years.  The 
earliest  cases  were  associated  with  a  deciduous 
tooth,  but  only  four  such  cases  are  recorded. 
Of    the    pernvmcnt    series    any    tooth    may 


molars  have  been  involved  more  often  than  the 
first  or  second  molars. 

A  description  of  the  macroscopical  appearances 
of  the  cyst  is  best  made  from  the  conditions 
found  at  the  operation. 


Fig.  967. — Section  of  the  cap  of  tissue  of  an  eruption  cyst. 
Tliis  section  shows  the  superficial  epithelium  and  fibrous  connective  tissue,  whilst 
on  the  side  nearest  the  tooth  a  thin  layer  of  epithelium,  which  lined  the  cyst, 


can  be  seen. 


Fig.  9GG. — Epithelial  lining  and  capsule  of  a  deiitigerous  cyst 
associated  with  a  riplit  maxillary  canine.  Epithelial  cells 
were  found  in  the  fluid  contents  of  the  cyst.  (Ca^e  recorded 
in  Proc.  Roy.  Soc.  of  Med.  (Odoiit.  Sec),  1911,  p.  85.) 


be  involved ;  the  canines  have  been  most 
comir.only  affected ;  the  third  mandibidar 
molars  are  next  in  order  of  frequency,  followed 
bj-  the  lateral  inei.sors,  and  then  the  central 
incisors  of  the  maxillae.  The  mandibular 
premolars  have  been  more  often  affected  than 
those  of  the   maxillae.      The  third   maxillary 


The  tissues  removed  in  opening  up  the  cj'st 
consist  of  the  muco-periosteum,  bone,  a  fibrous 
adventitious  capsule  (formerly  thought  to  be  de- 
rived from  the  tooth-follicle),  and  the  epithelial 
lining.  The  lining  presents  a  smooth  or  slightly 
papillated  surface  ;  at  times  the  papillae 
may  be  quite  large.  Most  frecjuently  a 
deficiency  in  the  wall  is  present  where 
the  tooth  is  situated. 

Usually  the  tooth  is  normal  in  shape 
although  not  fully  developed.  Its  re- 
lationship to  the  cystic  cavity  is  best 
seen  on  opening  the  cyst  at  the  opera- 
tion for  removal. 

When  the  tumour  is  incised  the 
contained  fluid  escapes ;  it  is  found  to 
be  very  variable  in  character  in  different 
cysts — it  may  be  viscid  and  glairy,  or 
consist  of  a  yello\\ish  pultaceous  mass. 
Cholesterin  crystals  have  been  found 
in  the  former,  whilst  the  latter  consist 
of  debris  of  epithelial  cells,  some  of 
which  can  be  stained  (17). 

When  the  cavity  is  thoroughly  dried 
out,  the  tooth  is  usually  seen  projecting 
into  it ;   the  commonest  relationship  is 
for  the  crowii  to  be  surrounded  by  the 
cystic  cavity  and  the  root  to  be  em- 
bedded in  the  neighbouring  bone,  the 
capsule  being  attached  to  the  neck  of 
the  tooth.    In  fact,  the  appearance  suggests  the 
removal  of  the  tissues  around  the  crown  by  the 
growth  of  the  cystic  cavity. 

The  cyst  may  be  intact,  the  tooth  lying 
completely  out  sideit ;  the  tooth  is  then  not  visible, 
or  is  only  indistinctly  seen  if  the  tissue  imme- 
diately over  the  tooth  is  thin  and  tears  in  the 


748 


attempt  at  removal  (Fairbank's  case).  Li  these 
cases  the  origin  of  the  cyst  would  appear  to  be 
rather  from  the  tooth-band  than  the  enamel- 
organ.  The  resemblance  between  a  dental  cyst 
and  a  dentigerous  cyst  is  well  seen. 

Cases  are  recorded  where  the  tooth  has  been 
found  free  in  the  cyst  cavity ;    the  bone  would 


(Museum  of  the  Royal  College  of  Surgeons 


Fig.  968. — Dentigerous  cyst 
of  England. ) 

The  following  is  the  account  given  in  the  catalogue — 

The  left  side  of  the  body  of  a  lower  jaw  expanded  into  a  large  cyst 
to  the  inner  wall  of  which  a  retained  canine  tooth  is  attached.  The 
cyst  was  lined  with  a  thick  vascular  membrane,  composed  of 
granulation  and  fibrous  tissues  and  showing  no  trace  of  epithelium. 

From  a  girl  aged  thirteen.  It  had  been  observed  for  six  months 
before  operation.  There  was  some  enlargement  of  the  right 
side  and  the  teeth  were  very  irregular.  No  opening  in  the  cyst 
could  be  detected  although  there  was  a  constant  offensive  dis- 
charge from  its  surface.  The  disease  being  taken  for  a  solid 
tumour,  the  affected  half  of  the  jaw  was  excised  by  the  late 
Mr.  Fearn,  of  Derby.  The  patient  recovered.  (See  British 
Medical  Journal,  Vol.  II,  18G4,  p.  241 ;  atid  He.\th,  Injuries  and 
Diseases  oj  Jaw,  2nd  edition,  p.  165,  1872.) 

[Presented  by  Christopher  Heath,  1868.) 

Suppuration  had  taken  place,  and  this  accounts  for  the  absence  of 
an  epithelial  lining. 

appear  to  have  been  destroyed  around  the  tooth 
either  by  a  process  of  extension  of  the  cyst  or 
as  the  result  of  suppuration. 

In  most  cases  the  tooth  is  normally  formed 
althougli  incomplete ;  but  it  may  be  merely 
a  maldeveloped  denticle.  It  has  been  stated 
that  no  proper  pulp-cavity  is  present  in  teeth 
found  in  dentigerous  cysts.  A  point  that  has 
excited  interest  for  a  long  time  is  the  presence 


or  absence  of  Nasmyth's  membrane.  It  is  cer- 
tainly found  on  some  teeth  from  dentigerous 
cysts,  although  its  presence  is  denied  by  some 
observers. 

Micro.scopical  examination  of  the  cyst-wall 
demonstrates  the  presence  of  an  epithelial 
lining,  which  may  be  only  two  or  three,  or  many 
cells  deep.  The  mode  of  growth  can 
be  observed ;  marginal  cells  can  be 
seen  undergoing  prohferation,  whilst 
the  more  central  ones  are  degenerat- 
ing. The  latter  process  is  best  seen 
by  examination  of  the  fluid  from  the 
cyst  or  a  scraping  of  the  lining. 
Smears  made  upon  slides  show  a 
quantity  of  epithelial  debris,  with 
cells  in  all  stages  of  degeneration, 
some  of  which  hardly  stain,  whilst 
others  do  so  more  readily  ;  the  nuclei 
maybe  seen  to  be  undergoing  division. 
The  adventitious  capsule  consists 
of  fibro-cellular  tissue,  as  in  the  case 
of  other  slowly  growing  innocent 
tumours. 

Patients  with  dentigerous  cysts  do 
not  suffer  any  pain,  but  present 
themselves  for  treatment  on  account 
of  a  swelling,  which  gradually  in- 
creases in  size. 

On  examination  a  swelling  is  found 
bulging  the  alveolar  border,  which  in 
the  earliest  stages  may  affect  the 
outer  plate  only  ;  as  the  cyst  increases 
in  size  the  outer  plate  is  nearly  always 
more  affected  than  the  inner  one. 

At  first  a  rounded  bony  swelling 
is  found ;  later  the  bone  is  thinned, 
and  new  bone  is  formed  by  the 
periosteum  until  a  thin  layer  may 
exist,  which  jrields  to  pressure,  giving 
a  characteristic  feeling — parchment 
or  egg-shell  crackling.  With  further 
increase  in  size  of  the  cyst,  fluctuation 
is  obtained,  which  may  be  felt  even 
through  the  whole  thickness  of 
alveolus,  from  the  inner  to  the  outer 
side. 

Tlie  swelling  is  deep  in  the  jaw, 
and  as  a  rule  does  not  interfere  \vith 
the    neighbouiing    teeth    unless    the 
tumour  is  large,  when  lateral  displace- 
ment of  the  teeth  may  occur,  and 
the  jaw  be  markedly  deformed,  or  injury  may 
result,  with  infection  and  its  sequelae.     Sup- 
puration and  necrosis  are  not  commonly  seen,  as 
the  cysts  are  generally  treated  before   severe 
inflammatory  conditions  are  established. 

The  absence  of  a  tooth  from  the  series  is  a 
point  of  great  significance,  although  it  must  be 
remembered  that  dentigerous  cysts  have  been  re- 
corded in  connection  with  supernumerary  teeth. 


749 


Treatment. — The  treatment  consists  in  com- 
plete removeal  of  the  cyst  ^\^thin  its  capsule, 
and  extraction  of  the  tooth ;  care  must  be  exer- 
cised to  avoid  leaving  a  portion  of  the  cyst- wall 
in  the  neighbourhood  of  the  tooth. 

The  operation  is  easily  carried  out  by  incising 
the  cyst,  seizing  the  cyst  capsule,  and  gradually 
separating  it  from  the  bony  cavity  in  which 
it  is  situated.     The  wound  should  not  be  packed 


Flu.  UtJ'J.  {M (tscu/ii  vj  Un'  Royal  College  of  Surgeons  of 
England. ) 

It  is  probably  a  dentigerous  cyst  whose  walls  have 
undergone  calcification.  The  tooth  is  seen  at 
the  side  of  the  specimen.  The  following  notes 
are  from  the  museum  catalogue — 

A  right  superior  maxilla  showing  the  calcified  wall 
of  a  cyst,  which  in  great  part  fills  the  antrum. 
The  antral  cavity  does  not  appear  dilated,  except, 
perhaps,  to  a  slight  extent  posteriorly.  The  cyst 
walls  are  continuous  with  those  of  the  antrum 
below  and  on  the  outer  side,  but  above  are  separ- 
ated by  a  considerable  interval  from  the  roof  of 
the  cavity.  They  are  exceedingly  delicate,  and 
perforated  by  minute  apertures.  The  alveolus 
of  the  second  premolar  t)pens  into  the  floor  of 
the  eyst.  Tlie  origin  of  the  cyst  is  uncertain; 
perhaps  it  was  inflammatory,  and  connected 
with  the  fang  of  the  second  pren^olar. 

(Presented  by  Sanitiel  Cartwright,  1888.) 

except  in  case  of  haemorrhage,  but  cleanliness 
and  drainage  maintained  by  fretiuent  irrigation  ; 
a  weak  antiseptic  lotion,  such  as  potassium 
permanganate  or  hydrogen  peroxide,  may  be 
alternated  with  normal  salt  solution  or  merely 
boiled  water. 

3.  Dental  Cysts 

Dental    Cysts    are    innocent    simple    cystic 
tumours    arising,    as    the    result    of    irritation, 


from  the  dental  epithelium  about  tiie  root  of 
a  tooth  that  has  undergone  eruption. 

Dental  cysts  have  long  been  recognized,  but, 
probably  on  account  of  the  uncertainty  that 
has  existed  concerning  tbeir  pathology,  have 
not  been  placed  in  any  particular  pathological 
group.  Their  origin  and  nature  i'.rc  now  estab- 
lished beyond  doubt ;  the  vie\\-  put  forward  by 
Malassez  (18)  in  1885  has  been  univer.sally  ac- 
cepted since  the  corroboration  of  his  work  by 
J.  G.  Turner  (25)  in  1898.  It  is  no  longer 
possible,  therefore,  to  include  multilocular  cysts 
and  dentigerous  cysts  among  odontomes  without 
classifying  dental  cysts  with  them  also. 

It  has  already  been  pointed  out  that  the 
dental  epithelium  exists  as  enamel-organs  and 
as  irregular  columns  and  collections  of  epithelium 
(Intermediary  Plexus  of  Malassez  :  Comiecting 
Bridges  of  Rose)  situated  between  the  enamel- 
organs  and  the  superficial  epithelium. 

Malassez  showed  that  prior  to  the  eruption 
of  the  teeth,  epithelium  (debris  epitheliaux 
paradentaires)  was  present  in  the  tissues,  and 
that  the  teeth  erupting  through  the  tissues 
became  associated  with  these  collections  of 
epithelial  cells.  The  more  recent  view  that  the 
cells  are  derived  mainly  from  the  extension  of 
tlie  enamel-organ  known  as  the  sheath  of  Hert- 
wig  ( 15)  is  probably  the  more  correct.  Malassez 
pointed  out  that  the  collections  of  cells  are 
found  chiefly  in  the  periodontal  membrane 
near  to  the  tooth,  but  also  in  the  external 
part,  and  even  in  the  bone  ;  and  besides  these, 
in  the  gingival  tissues.  He  was  of  the  opinion 
that  any  of  these  collections  of  cells  might  give 
rise  to  dental  cysts. 

The  development  of  a  dental  cj'st  is  the 
result  of  proliferation  and  degeneration  of  these 
epithelial  cells.  The  cells  increase  in  number 
until  a  collection  results,  which  has  been 
described  by  J.  G.  Tiu-ner  as  an  "  Epithelial 
Root  Tumour";  with  further  proliferation  the 
central  cells  undergo  degeneration,  and  breaking 
down  produce  a  central  fluid  area.  This  process 
of  degeneration  of  the  more  centrally  situated 
cells  associated  with  proliferation  of  the  marginal 
cells  leads  to  a  cystic  cavity  lined  by  an  epi- 
thelium. By  a  continuation  of  the  process 
large  cysts  results.  The  cause  of  the  degenera- 
tion of  the  central  cells  has  been  explained  by 
their  becoming  cut  otf  from  luitriiuent  by  the 
proliferation  of  the  marginal  cells.  With  the 
growth  of  the  cyst,  changes  occur  in  the  sur- 
rounding tissues,  absorption  takes  place,  and 
an  adventitious  capsule  is  jiroduced.  The 
tooth  is  u.sually  unaffected  by  tiie  growth,  but 
the  bone  is  absorbed,  and  the  (M'riosteum  of 
the  alveolar  plates  in  due  course  becomes 
affected,  and  the  formation  of  new  bone  results. 
Absorption  and  deposition  contimu-  initil  the 
periosteum  no  longer  produces  sufficient  bone 


750 


to  cover  the  cyst,  when  a  soft  area  can  be 
discerned  where  fluctuation  is  obtainable.  The 
changes  just  described  in  the  bone  are  often 
spoken  of  as  "  distension  of  the  bone  ",  and 
although  the  changes  have  the  appearance  of 
a  process  of  distension  they  are  really  due  to 
absorption  and  new  formation. 

The  structure  of  dental  cysts,  therefore, 
varies  with  the  stage  at  which  the  tumours 
are  examined ;  at  first  they  are  merely  a  collec- 
tion of  epithelial  cells,  and  can  be  frequently 
observed  upon  the  roots  of  extracted  teeth. 
They  occur  upon  any  part  of  tlie  root,  although 
most  frequently  in 'the  apical  region,  and  are 
seen  as  rounded  nodules  either  discrete,  when 
they  are  attached  to  the  periodontal  memlirane 
sometimes  by  a  pedicle  only,  or  embedded  in 
the  substance  of  a  thickened  periodontal  mem- 
brane.    Later  they  may  be  removed  with  the 


Fig.  97(J. — A  small  dental  cyst  attached  to  the  root  of 

a  molar  tooth. 
From  J.  G.  Turner's  series  of  specimens.     {Museum 
of  the  Royal  Dental  Hospital  of  London.) 

tooth  as  large  as  a  filbert  nut,but  as  they  increase 
in  size  they  become  more  dissociated  from  the 
tooth  and  exist  in  a  Ijony  cavity.  Inside  this 
cavity  is  the  fibrous  capsule  (adventitious  cap- 
sule), which  surrounds  the  epithelium  comprising 
the  true  tumour.  Wien  the  cyst  is  large  the 
quantity  of  fluid  may  be  very  considerable, 
forming  the  greater  part  of  the  tumour.  The 
cysts  are  usually  simple,  but  occasionally 
secondary  minor  cysts  can  be  seen  associated 
with  the  main  cysts,  and  at  other  times  papuli- 
ferous projections  into  tlie  cyst  may  be  observed. 

Cysts  have  been  described  as  possessing  a 
fibrous  capsule  only,  and  were  thought  to  be 
due  to  the  accunuilation  of  fluid  in  what  was 
described  as  a  chronic  fibscess  sac  :  they  were 
probably  true  dental  cysts  from  which  the 
epithelial  lining  was  lost  during  preparation 
of  the  microscopical  sections,  or  cysts  in  which 
suppuration  had  taken  place  with  destruction 
of  the  epithelium,  either  completely,  or  of  the 
part  from  which  the  section  was  taken. 

The  cyst  wall  is  usually  of  a  more  or  less 


uniform  thickness.  The  epithelial  wall  may 
consist  of  one  or  two  cells  only,  or  it  may  be 
twenty  or  more  deep  ;  occasionally  degeneration 
takes  place  eccentrically,  when  one  part  of 
tlie  wall  may  be  considerably  thicker  than 
another.  The  adventitious  capsule  derived 
from  the  connective  tissue  is  chiefly  composed 
of  white  fibrous  tissue  with  some  cellular 
elements  ;  in  a  rapidly  growing  cyst  it  is  usually 
quite  thin,  whilst  a  more  chronic  type  may 
possess  a  capsule  of  a  considerable  thickness. 

The  epithelial  cells  are  found  to  be  more  or 
less  polyhedral  or  irregular  in  shape.  They 
show  proliferative  changes  with  deeply  stained 
nuclei,  and  degenerative  changes  with  cells 
that  are  swollen  and  do  not  stain  readily ; 
epithelial  debris  and  free  degenerated  cells  may 
be  demoni?trated  in  the  fluid  contents.  An 
analysis  of  the  fluid  from  dental  cysts  given 
by  J.  G.  Turner  (25)  demonstrated  the  presence 
of  cholesterin  in  abundance,  but  no  fats  or 
fatty  acids.  Serum-globulin  and  also  serum- 
albumen,  were  found,  the  latter  in  a  far  lower 
proportion  than  the  former.  A  nucleo-proteid 
was  also  present. 

The  fluid  is  usually  of  a  brownish  colour  in 
large  cysts  and  of  a  viscid  consistency. 

The  immediate  cause  of  the  development  of 
a  cy.st  is  probably  irritation,  and  the  commonest 
irritant  appears  to  be  the  toxic  products  of 
micro-organisms.  The  presence  of  a  carious 
tooth  has  been  regarded  as  an  essential  factor, 
although  the  occurrence  of  a  cyst  unassociated 
witli  dental  caries  has  been  recorded.  The 
view  that  "  pyorrhoea  alveolaris  "  can  act  as 
a  stimulus  is  now  generally  accepted.  It  is 
also  possible  that  local  injury  may  supply  the 
necessary  irritation.  Attempts  to  cultivate 
organisms  from  cysts  that  have  been  opened 
aseptically  have  given  negative  results. 

There  is  little  doubt  that  dental  cysts  most 
frequently  arise  in  septic  mouths,  but  it  is 
necessary  to  remember  that  such  conditions  of 
the  mouth  are  of  very  common  occurrence. 

Dental  cysts  occur  in  the  maxiUae  and  in  the 
mandible  of  human  beings  of  either  sex.  All 
cases  so  far  recorded  have  occurred  after  erup- 
tion of  permanent  teeth :  the  earliest  case  was 
in  a  patient  aged  nine  years,  and  the  latest  at 
fifty-six  years.  They  are  more  common,  per- 
haps, between  twenty  and  forty  years,  but 
no  particular  age  is  markedly  favoured.  It 
cannot  he  said  that  any  particular  area  of  the 
mouth  is  more  frequently  affected  than  another, 
but  the  first  molar  region  is  usually  regarded 
as  the  commonest  site. 

The  distriljution  of  dental  cysts  in  the  cases 
collected  by  J.  G.  Turner  followed  closely  the 
situation  of  the  teeth  most  frequently  affected 
by  dental  caries,  but  the  number  of  cases 
collected  is  too  few  to  base  a  conclusion  upon, 


751 


altliougli  tlie  inference  drawn  is  certainly 
suggestive.  So  little  investigation  has  been 
done  with  regard  to  race  or  zoological  distribu- 
tion that  no  statement  is  possible. 

A  general  statement  made  by  J.  G.  Turner 
is  probably  true  and  of  sufficient  interest  to 
repeat  :  "  The  commonest  tumour  of  the  jaws 
and  the  commonest  cvst  of  bone  is  a  dental 
cyst." 

In  the  early  stages  of  development  of  a 
dental  cyst  its  presence  may  be  quite  unrecog- 
nizable, and  untU  the  bone  shows  some  change 
in  one  of  the  alveolar  plates  symptoms  or  signs 
are  absent.  A  small  cavity  in  the  bone  may 
be  accidentally  discovered  in  a  radiograph 
when  the  tumour  is  of  sufficient  size. 

The  earliest  symptom  is  usually  the  presence 
of  a  rounded  swelling  of  the  outer  alveolar 
plate,  commonly  at  a  level  near  the  apical 
region  of  tlie  teeth.  The  only  change  detected 
is  the  gradual  increase  in  size,  wliicli  continues 
until  the  inner  alveolar  plate  is  involved,  but 
this  is  not  marked,  except  in  the  case  of  very 
large  cysts.  With  the  increase  in  size  the  outer 
alveolar  plate  shows  great  '"  bulging ".  The 
thinned  plate  of  bone  jnelds  to  pressure  and 
gives  a  cliaracteristic  sensation  known  as 
"  parchment  crackling  ". 


Fio.  971. — Uental  r\^i  ;iita(li.-,l  lu  a  lirst  maxillary 
molar.  Kemoved  from  a  man  suffering  from 
"  pyorrhoea aheolaris  "  ;  tartar  has  been  deposited 
and  can  be  seen  almost  to  the  apex  of  the  palatal 
root.     (Presented  to  the  writer  by  R.  H.  Heath.) 

Wlien  the  periosteum  no  longer  forms  new 
bone  over  the  whole  cyst,  a  soft  area  can  be 
detected  where  fluctuation  can  be  obtained, 
and  the  sharp  thinned  margin  of  bone  is  readily 
distinguished.  Tlie  shape  of  the  swelling  is 
always  romidcd,  indicating  the  fluid  nature 
of   the   tumour,    for   the    pressure   within    the 


cyst  nnist  be  equal  in  all  directions,  as  the 
contents  are  fluid ;  where  the  resistance  is 
greater  in  one  part  than  another,  as  is  the 
case  where  a  tooth  is  present,  the  globular 
character  is  interrupted  at  that  point.  Pain 
is  absent   unless  the   tumour  is  large   enough 


Fig.  972. — A  dental  cyst. 
From    .J.   G.    Turners    series  of   specimens.      (Twice 
natural  size.)    (Museum  of  the  Royal  Dental  Hospital 
of  London. ) 

to  be  injured,  as  during  mastication  or  by  an 
opposing  tooth.  Discomfort  may  be  caused 
by  the  size  of  the  tumour,  and  also  by  the  dis- 
placement of  the  overlying  soft  tissues,  and 
external  swelling  of  the  face  and  jaw  may  be 
noticeable.  Pressure  upon  the  inferior  alveolar 
nerve  may  cause  numbness  over  the  area  of 
its  distribution. 

The  size  of  the  swelling  is  the  chief  cau.se  of 
relief  being  sought  by  the  patient.  Suppuration 
not  infrequently  supervenes  and  compels  the 
patient  to  seek  relief. 

The  gum  tissue  over  the  swelling  does  not 
at  first  show  any  change  in  appearance,  but 
when  the  bone  is  considerably  destroyed  a 
bluish  appearance  is  usually  present. 

If  the  cyst  has  been  injured  and  perforated 
a  brownish  fluid  continues  to  discliarge,  which 
later  becomes  mixed  with  pus.  The  wall  of 
the  cyst  where  the  bone  has  been  destroyed 
has  collapsed,  and  presents  a  small  opening 
leading  into  the  cyst  and  from  which  the  dis- 
charge takes  place.  If  the  inflammation  has 
been  acute  a  portion  of  the  cyst  wall  may  have 
sloughed  away,  leaving  the  cavity  open  with 
a  rugged  margin ;  the  cavitj'  is  then  lined  by 
granulation  ti.ssue,  and  small  pieces  of  necrosed 
bone  may  be  found  in  its  walls.     Necrosis  will 


752 


occasionally  be  more  extensive,  occurring  in 
those  cases  where  drainage  is  imperfect  or 
the  inflammation  very  severe. 

Li  the  maxilla  tlie  growth  of  the  cyst  not 
uncommonly  extends  into  the  maxillary  sinus ; 
a  communication  is  not  often  established,  but 
the  floor  is  pushed  up.  This  process  may  go 
on  to  such  a  degree  as  almost  to  obliterate 
the  maxillary  siims,  converting  it  into  a  mere 
slit  beneath  the  orbit  or  against  the  outer 
wall  of  tlie  nasal  cavity ;  the  capsule  of  the  cyst 
alone  may  be  present  between  the  two  cavities. 
A  radiograph  is  always  of  value  in  determining 
the  size  and  position  of  tlie  cyst. 

Dental  cysts  occur  that  present  different 
clinical  appearances  from  those  given ;  they 
may  be  situated  for  the  most  part  on  the 
palatal  aspect  of  the  maxiUa  or  the  lingual 
aspect  of  the  mandible,  or  even  involve  the 
deeper  structures  without  markedly  affecting 
the  alveolar  plates,  but  these  types  are  certainly 
uncommon. 

Treatment. — The  removal  of  dental  cysts 
should  be  undertaken  at  as  early  a  stage  as 
possible,  for  they  will  continue  to  increase  in 
size  and  may  cause  marked  deformity.  A  free 
opening  should  be  made  into  the  cyst,  the 
fluid  removed,  and  the  cyst  wall  with  the 
fibrous  capsule  separated  in  one  piece  from  its 
bony  cavity.  The  capsule  can  usually  be  seized 
at  one  point  and  torn  from  the  bone,  the  remain- 
ing part  of  the  capsule  being  gradually  separated 
by  the  aid  of  a  periosteal  elevator.  A  suffici- 
ently large  opening  into  the  cavity  wiU  allow 
free  drainage.  At  the  time  of  the  operation 
packing  may  be  necessary  to  arrest  haemorrhage, 
but  unless  the  opening  is  small  it  is  unnecessary 
otherwise  to  introduce  any  packing  material. 

The  cavity  should  be  frequently  irrigated 
with  a  weak  antiseptic  lotion,  such  as  potassium 
permanganate,  hydrogen  peroxide,  or  carbolic 
acid. 

Wlien  suppuration  has  occurred  in  a  cyst, 
the  lining  membrane  should  not  be  disturbed, 
at  least  until  tlie  cavity  has  been  rendered 
aseptic.  Removal  of  the  lining  membrane  is 
probably  rendered  unnecessary,  as  destruction 
of  the  lining  epithehum  usually  results.  A 
free  opening  should  be  made  and  irrigation  with 
antiseptic  lotions  undertaken  several  times 
during  the  day.  If  the  cavity  is  not  easily 
rendered  clean,  scraping  may  be  necessary  in 
order  to  remove  any  sloughs  or  portions  of 
necrosed  bone.  It  is  unusual  to  find  irrigation 
through  a  free  opening  insufficient. 

Carcinomatous  Odontomes. — Odontomcs  of  a 
carcinoiiiatoiis  nature  have  been  described  by 
Sir  Frederic  Eve  (11)  as  "Epithelial  Odontomes  | 
(carcinoma)  ";  he  is  of  the  opinion  that  several 
tumours  described  as  spheroidal-  or  columnar- 
celled   careinomata   have  originated   from    the 


dental  epithelium.  The  tumours  he  particularly 
refers  to  are  those  that  are  found  in  the  maxil- 
lary sinus  and  have  been  thought  to  arise  there. 
Certain  tumours  found  in  the  maxilla  have  been 
described  as  "  burrowing  epithelioma  ",  and  are 
thought  possibly  to  have  arisen  from  the  dental 
epithelial  remnants  associated  \\ith  the  teeth. 
In  one  or  two  of  these  rare  cases  a  tooth  has 
been  removed,  an  abnormal  condition  found, 
the  socket  has  not  healed  in  the  normal  manner, 
and  the  growth  has  protruded  from  the  socket. 
A  microscopical  section  revealed  the  nature  of 
the  tumour.  The  degree  of  malignancy  appears 
to  have  been  low. 

Tiie  carcinomatous  odontomes,  with  the  sar- 
comatous type,  need  further  investigation  before 
they  can  be  established  as  a  definite  variety. 
The  credit  of  the  investigation  of  these  cases  is 
due  mainly  to  Sir  Frederic  Eve. 

II.— COMPOSITE    ODONTOMES 

This  term  was  formerly  used  by  Sir  J.  Bland- 
Sutton  for  those  irregular  masses  of  calcified 
dental  tissue  that  have  no  external  resemblance 
to  a  tooth — described  by  him  as  an  aberration 
of  the  whole  tooth-germ.  As  the  development 
of  dentine  occurs  only  in  the  presence  of  an 
enamel-organ  [Von  Brun  (26)],  and  as  the  latter 
determines  the  form  taken  by  the  dentine,  it 
follows  that  the  aberration  takes  place  primarily 
in  the  enamel-organ.  All  odontomes,  therefore, 
that  contain  dentine  must  be  due  to  aberrations 
of  the  enamel-organ.  The  presence  or  absence 
of  cementum  or  an  osteoid  tissue  varies  :  it 
may  be  abundant  or  almost  absent.  These 
odontomes  are  all  calcified,  and  correspond  very 
closely  with  a  normal  tooth  in  their  relationship 
to  the  surrounding  tissues,  and,  except  for 
their  bulk  in  some  cases,  which  favours  local 
pathological  changes,  they  will  undergo  "erup- 
tion ".  A  composite  odontome  may  be  present 
in  a  dentigerous  cyst,  and  the  presence  of  a 
cystic  condition  in  a  compound  composite 
odontome  (compound  follicular  odontome)  may 
also  be  accounted  for  in  this  way. 

The  following  definition  has  been  used  for 
the  tumours  of  the  group  :  Composite  odontomes 
are  calcified  tooth  tumours  composed  of  a 
disordered  conglomeration  of  enamel  and  den- 
tine, with  cementum  varying  from  a  large  to 
a  very  small  quantity.  Considerable  variation 
is  found  in  the  tumours  of  this  group.  The 
tumour  depends  upon  the  stage  of  development 
at  which  the  tooth-germ  deviates  from  the 
normal,  and  the  degree  of  distortion  that 
results. 

For  the  convenience  of  classification  some 
arrangement  of  the  tumours  can  be  made  into 
groups,  which  roughly  correspond  with  the 
period  at  which  aberration  probably  took  place. 


753 


Tlie  different  groups  are  described  under  their 
respective  headings.  \Miere  the  component 
tissues  are  so  irregularly  arranged  tliat  they 
appear  to  hav-e  no  particular  relationship  to 
one  another,  the  odontome  has  been  called  a 
"  complex  composite  odontome".  Others  pos- 
sess characteristics  sufficiently  common  to 
justify  the  grouping,  and  show  a  closer  re- 
semblance to  a  normal  tooth  according  to  the 
period  at  which  the  aberration  took  place  ;  .so 
that  in  some  specimens  the  crow^l  of  the  tooth 
may  be  quite  complete.  The  grouping  also 
depends  upon  whether  a  single,  or  more  than 
one.  tooth-germ  has  been  involved. 

No  explanation  has  3'et  been  given  to  account 
for  the  production  of  these  odontomes,  beyond 
those  to  which  reference  has  already  been 
made.  Where  the  family  history  has  been 
obtained  there  does  not  appear  to  be  any 
evidence  that  more  than  one  member  of  a 
family  has  suffered  from  this  type  of  tumour. 

The  soft  ti-ssues  surrounding  composite  odon- 
tomes have  been  described  in  only  one  or  two 
cases,  when  a  fibro-cellular  capsule  was  found 
to  be  present. 

No  account  has  yet  been  given  of  one  of 
these  tumours  undergoing  development ;  at 
present,  therefore,  a  comparison  with  normal 
tooth  development  is  the  only  possible  source 
of  information,  and  one  that  must  be  regarded 
as  unsatisfactory. 

The  age  of  the  patient  when  the  tumour 
appears  is  most  variable ;  those  that  have  a 
close  resemblance  to  a  tooth  and  are  small 
may  "erupt"  into  the  arch  in  a  manner 
similar  to  that  of  a  normal  tooth,  but  the 
irregular  and  larger  ones  may  be  retained  in 
the  jaw  for  years,  becoming  exposed  deep  in 
the  tissues.  Their  appearance,  in  almost  all 
cases,  occurs  after  the  normal  period  of  "  erup- 
tion ".  The  first  recognition  of  a  composite 
odontome  is  frequently  the  presence  of  sup- 
puration, which  is  often  mistaken  for  necrosis 
of  the  jaw. 

Radiographs  are  very  valuable  in  these  cases. 
Tlie  size  of  the  tumour  will  determine  the  degree 
of  deformity  of  the  jaw  ;  this  may  be  considerable, 
as  the  changes  associated  with  its  development 
are  so  gradual  that  the  patient  is  caused  practi- 
cally no  inconvenience.  Relief  may  be  .sought 
on  account  of  the  deformity  or  the  presence  of 
a  swelling :  occasionally  pain  occurs,  which  is 
of  a  vague  character  or  due  to  injury,  when 
inflammation  is  often  established.  Suppuration 
with  necrosis  is  not  uncommon,  and  induces 
the  patient  to  seek  relief.  Periodontitis  of 
neighbouring  teeth  may  be  set  up  by  extension 
of  the  inflammation. 

Composite  odontomes  are  found  in  the  maxilla 
and  the  mandible  of  the  human  subject  in 
both    sexes,    and   are    also    found    in    animals. 


In  man  the  largest  tumours  have  occurred  in 
the  maxilla,  probably  from  the  presence  of  the 
maxillary  sinus,  which  allows  growth  to  take 
place  without  marked  evidence  externally. 
Any  area  of  the  mouth  may  be  involved ;  the 
exact  tooth -germ  affected  camiot  always  be 
determined  ;  the  canine  is  perhaps  most  rarely 
involved,  whilst  the  molar  region  is  possibly 
the  commonest  site. 

One  characteristic  of  some  interest  is  the 
frequent  occurrence  of  a  normal  tooth  beneath 
the  odontome.  This  condition  has  been  ob- 
served so  often  that  it  is  necessary  to  make 
an  examination  of  the  cavity  after  removal  of 
the  odontome  for  the  presence  of  a  tooth. 

An  irregular  swelling  of  the  bone  (with  absence 
of  a  tooth  or  teeth)  that  has  existed  for  a  long 
period  and  has  very  gradually  increased  in  size, 
will  suggest  an  odontome.  A  radiograph  should 
be  taken  if  an  odontome  is  suspected. 

If  a  sinus  is  present  and  a  probe  is  passed, 
the  hard  dense  character  of  the  tissue  is  quite 
distinct  from  bone ;  if  the  odontome  is  sur- 
rounded by  granular  tissue,  as  the  result  of 
suppuration,  it  may  be  movable.  If  a  part 
of  the  tumour  is  visible  or  can  be  exposed  its 
nature  is  easily  determined. 

Treatment. — The  tumour  should  be  removed, 
except  where  it  is  small  and  of  some  value  to 
the  patient. 

Great  care  should  be  taken  to  render  the 
mouth  as  clean  as  possible  before  removing 
an  odontome.  Extensive  laceration  of  tissue, 
with  the  production  of  a  large  cavity,  must 
result  if  the  tumour  is  large,  and  infection,  with 
suppuration  and  necrosis  or  even  more  serious 
consequences,  may  ensue.  Every  effort  should 
be  made  to  perform  the  operation  under  the 
most  favourable  circumstances. 

Antiseptic  mouth-washes  should  be  used,  and 
frequent  irrigation  of  the  cavity  from  which 
the  odontome  was  removed  should  be  carried 
out. 

1.  Complex  Composite  Odontomes 

Complex  composite  odontomes  are  those 
composite  odontomes  that  have  their  tissues 
irregularly  intermingled  and  liave  no  definite 
shape. 

This  sub-group  comprises  the  greater  number 
of  odontomes  named  by  Sir  J.  Bland-Sutton 
■■  Composite  Odontomes  ",  which  constitute  a 
main  group  in  his  classification. 

Complex  composite  odontomes  bear  no  re- 
semblance to  a  normal  tooth  in  external  aj)pear- 
ance,  and  consist  of  a  shapeless  mass  of  calcified 
dental  tissues.  They  are  usually  of  a  rounded 
form  with  an  irregular  surface,  which  may 
vary  from  behig  merely  rougli  to  having  a 
deeply  pitted  or  even  stalactitic  appearance. 
The  surface  varies  in  different  parts  of  the  same 


754 


tumour :  one  may  be  hard  and  rounded,  whilst 
another  may  be  most  irregular  and  even  present 
a  marked  depression. 

The  stnicture  of 
the  tumour  cannot 
be  determined 
from  its  superficial 
appearance,  but 
small  nodules  or 
patches  of  enamel 
may  be  seen. 

These  odontomes 
vary  considerably 
ill  size  ;  they  may 


Fig.  973. 


Fig.  974 


Complex  composite  odontome.  and  model  showing  the  appearance  presented  prior  to  operation 
(see  interrupted  line).      The  tissues  overlying  the  odontome  had  been  perforated  and 


(see  interruptu...  — ^,.      -         .      ^  ,        ,    ,         ,      ,        ,  -,  ^i        i        i 

infected.     The  upper  siu-face  of  the  odontome  was  just  below  the  level  of  the  alveolar 
border.     (Natural  size.)     (Ritssell  B.irrett's  co«e.     Recorded--    '^  ^''-"'    •■'"- 

1897-8,  Vol.  XXX,  p.  21.) 


Trans.  Odont.  Soc, 


be  quite  minute  or  measure  as  much  as  three  or 
more  inches  in  the  longest  axis ;  the  weight  in 
one  case  was  as  much  as  850  grains. 


Fig.  975. — Complex  composite  odontome.  [Museum 
of  the  Royal  College  of  Surgeons  of  England.) 

The  calcified  mass  has  partly  enveloped  the  root  of 
the  central  incisor,  but  is  not  connected  with  it. 
This  relationship  is  of  interest,  as  odontomes 
frequently  are  closely  associated  with  teeth,  but 
the  tooth  usually  lies  beneath  the  odontome. 

When  cut  accoss  they  are  found  to  be  exceed- 
ingly hard,  although  they  are  for  the  main  part 
very  friable  on  account  of  the  irregular  arrange- 
ment of  dense  with  softer  fragile  tissue. 


To  the  naked  eye  a  section  does  not  show  any 
particular  arrangement ;  some  sections  sho\\'  hard 
tissues  with  spaces,  which  may  be  very  irregular 

or  rounded  ui  out- 
Ime ;  a  section 
passing  from  the 
surface  towards 
the  centre  will 
often  show  a  radial 
arrangement.  The 
tissues  are  seen  to 
vary  m  composi- 
tion ;  enamel  may 
be  detected,  but 
t  h  e  irregularity 
and  imperfect  de- 
velopment of  the 
tissues,  which 
occurs  throughout 
the  tumour,  usu- 
ally renders  recog- 
n i t i o n  by  the 
naked  eye  impos- 
sible. 

Microscopical 
examination 
shows  these  odon- 
tomes to  be  com- 
posed of  enamel,  dentine,  and  cementum.  The 
enamel  may  be  well  developed,  or  imperfectly 
calcified  and  deeply  pigmented. 

The  dentine  may  show  a  hard-tubed  dentine, 
an  ill-formed  dentine  with  numerous  inter- 
globular spaces,  dentine  folded  so  as  to  resemble 
plicidentine,  and  a  vascular  tissue  described  as 
osteodentiiie. 

Cementum  is  usually  a  less  marked  constituent 

of   these   odontomes.   and    may   be   absent   or 

present  in  quite  small  amounts  ;    its  structure 

is  very  variable,  but  is  chiefly  of  a  coar.se  and 

irregular  character.     The  arrangement  of  these 

structures  in  relation  to  one  another  is  said  to 

be  quite  indefuiite.     Enamel  is  never  found  to 

form  a  complete  covering  to  the  hard  dentine, 

as  might  be  expected  from  comparison  ■with  a 

tooth  ;   it  is  found  in  patches  even  in  the  centre 

of  the  tumour,  and  spaces  are  commonly  lined 

by  enamel,   which    may   or   may  not    be   well 

developed.     Alternate  formations  of  enamel  and 

dentine  are  found,  particularly  where  the  radial 

arrangement  is  .seen,  when  the  enamel  is  usually 

in  two  layers  with  a  space  between  them.     The 

careful  consideration  of  the  arrangement  of  the 

enamel  suggests   that   there   is  really  a   more 

regular  arrangement  than  is  generally  thought, 

for   in   A\hatever   position   enamel   is   found   it 

should  be  regarded  as  a  surface  structure.     The 

highly  complicated  folding  of  the  enamel-organ 

that  must  have  taken  place  to  produce  such  an 

arrangement   as   is   found   can   be   followed   in 

parts  of  some  of  these  tumours.     The  cause  and 


755 


f.    /■■-'if'         ..'"V.        h^  ^ 


y> 


5^ 


Vlr..  IITS. 


Kii;.  '.)(SU. 

Complex  composite  odontome  removed  from  the  mandible  of  a 
Kaffir  boy.  Presented  by  Morton  Smale.  [Museum  oj  the 
Uoyal  Dental  Hospital  of  London.) 

Tbo  specimen  weighs  855  grains  and  measures  70  X  62  X  39  mm. 
I'll.'  tumour  is  almost  entirely  composed  of  dentine  and 
irrogulurlv  calcified  material.  The  sections  ilhistratod  here 
show  well  the  nature  of  the  tissues  in  these  odontomcs.  A 
thin  layer  of  cemeiUmn  is  seen  upon  the  siu-face  of  the  tumoiu-. 
Dentine  can  be  observed  that  is  normal  in  appearance,  and 
also  whore  the  tubules  are  distorted:  in  parts  the  structiu-e  is 
so  irregular  as  hardly  to  justify  being  called  dentine,  and  one 
of  the  sections  particularly  shows  numerous  interglobular 
spaces.  J^ilp-channels  are  seen,  many  of  them  black,  as  they 
are  filled  with  debris.  Patches  of  enamel  are  found  as  a  rule 
either  on  the  surface  or  lining  a  cavity,  but  enamel  has  not 
been  discovered  in  this  specimen. 


756 


H*  4  ■'■" 


Fig.  98 1. — Some  o£  the  particles  composing  a  compound  composite 
odontome  removed  by  Tellander.  {Mitseum  of  the  Royal 
College  of  Surgeons  of  England.) 

The  case  is  of  interest  in  that  it  occurred  at  an  early  age  and 
there  is  no  suggestion  of  a  cystic  condition  being  present. 

The  following  is  the  account  given  in  the  catalogue — ■ 

History  of  Case. — At  the  age  of  twelve  a  hard,  painless  swelling 
occurred,  which  caused  disfigurement  but  no  pain.  Inflamma- 
tion round  temporary  molar  brought  her  to  Mr.  Tellander,  of 
Stockholm,  in  December  1861.  Patient  was  then  aged  twenty- 
four.  The  tooth  was  extracted,  but  the  trouble  persisted.  Mr. 
Tellander  then  decided  to  remove  the  pieces  of  loose  bone, 
which  he  thought  were  causing  the  enlargement  of  the  maxilla, 
but  after  removing  a  few  of  those  hard  particles  he  came  upon 
a  cluster  of  minute  teeth.  The  cavity  was  emptied  and  the 
contents  are  shown  on  this  card.  Probably  some  teeth  were 
lost,  but  no  less  than  twenty-eight  teeth  or  cusps  are  pre- 
served. There  are  nine  single  teeth,  each  one  perfect  in 
itself,  having  a  conical  root,  with  a  conical  crown  tipped  with 
enamel.  Six  masses  are  built  up  of  adlierent  single  teeth. 
Thus  one  is  composed  of  three  united  cusps,  two  others  have 
two  cusps  each,  the  fourth  is  but  an  irregular  mass  of  dental 
tissue,  and  the  fifth  consists  of  three  similar  masses  united  by 
membranes.  In  the  sixth  mass  no  less  than  nine  cusps  may  be 
traced.  The  teeth  present  the  usual  characteristics  of  super- 
numerary teeth.     {Trans.  Odont.  Soc,  1862,  Vol.  Ill,  p.  282. 


process  of  tlie  production  of  these 
odontomes  are  quite  unkiiowii,  and 
little  therefore  can  be  said  with  regard 
to  their  true  nature  beyond  what  can 
be  mf erred  from  their  structure. 

Cliannels,  ^\hich  probably  correspond 
\\ith  tlie  pulp-cavities  and  canals  of 
normal  teeth,  are  to  be  seen,  although 
a  single  pulp-chamber  is  most  unusual. 

These  odontomes  are  found  most 
frequently  in  the  molar  region,  and  the 
commonest  age  at  which  they  come 
under  observation  is  about  twenty  years. 
There  is  little  difference  in  the  frequency 
of  their  presence  in  the  mandible  or 
maxilla,  the  former  perhaps  behig  the 
commoner  site,  whilst  of  the  recorded 
cases  men  were  more  often  affected  than 
women. 

The  clinical  course  will  depend  usually 
upon  their  size.  With  absence  of  a 
tooth  and  the  presence  of  a  hard  swell- 
ing, the  diagnosis  will  not  be  mistaken  if 
a  careful  examination  is  made.  The 
odontome  i.s  usually  situated  below  the 
level  of  the  normal  teeth  ;  it  may  appear 
impacted,  but  without  obstruction  it  will 
be  seen  l3Tng  in  the  bone,  having  been 
exposed  rather  by  a  process  of  denuda- 
tion than  by  eruption.  Suppuration  is  a 
common  complication,  and  these  tumours 
have  been  mistaken  for  sequestra  of 
bone. 

Removal  of  the  odontome  is  generally 
necessary,  especially  when  it  is  large  or 
suppuration  is  present. 

2.   Compound  Composite  Odontomes 

Compound  composite  odontomes  are 
tumours  containing  several  separate 
calcified  masses  of  dental  tissue. 

The  accounts  given  of  the  few  cases 
on  record  that  can  be  jjlaced  together 
to  form  this  group  are  so  imperfect  that 
the  true  nature  of  the  tumours  cannot 
be  determined.  The  facts  are  definite 
in  one  or  two  respects  :  the  large  number 
of  fragments  of  calcified  tissue,  for  the 
most  part  consistmg  of  cementum  and 
bone,  is  the  most  constant  feature ; 
suppuration  and  necrosis  seem  to  have 
been  present  in  the  majority  of  cases. 
A  cystic  condition  is  spoken  of  in  con- 
nection with  many  of  the  cases,  but 
there  does  not  appear  to  be  sufficient 
evidence  to  confirm  the  statement ;  more 
than  one  operation  for  complete  re- 
moval has  been  necessary  in  nearly  all 
the  cases. 

Whatever  may  be  the  nature  of  these 
tumours  they  certainly  present  features 


757 


that  are  quite  exceptional.  Sir  J.  Bland-Sutton 
named  the  group  in  his  classifieation  "  Com- 
pound FoUicular  Odontomes  ",  but  the  word 
"  follicle  "  is  misleading,  as  only  one  of  the 
component  tissues  can  be  derived  from  this 
source,  and  if  cementum  alone  is  present  they 
should  be  grouped  with  the  cementonies.  The 
.sporadic  calcification  of  the  follicle,  which  is 
the  method  of  origin  given  by  Bland-Sutton, 
would  alone  account  for  cementum,  unless  calci- 
fication associated  with  degenerative  changes  be 
included.  It  seems  ^^^ser  therefore  to  change 
the  title  of  this  group,  as  has  been  done  in  the 
present  classification.  Possibly  when  more  cases 
liave  been  described  and  the  structure  of  the 
associated  soft  tissues  studied,  these  tumours 
may  be  included  with  one  of  the  more  defined 
groups.  The  cystic  nature  of 
the  tumour  may  be  estab- 
lished, and  if  so,  the  view  of 
0.  S.  Tomes  that  they  are 
dentigerous  cysts  %vith  nud- 
tiple  denticles  would  appear 
to  be  a  probable  explanation. 

Tlie  present  knowledge  of 
the  tumours  is  such  that  they 
should  be  classified  as  com- 
posite odontomes,  for  all 
dental  tissues  are  found  to 
be  present. 

The  account  of  compound 
composite  odontomes  in  the 
various  descriptions  given  of 
them  comprises  a  series  of 
cases  with  the  respective 
details  of  each.  The  cases  of 
Tellander  (23),  Mathias  (20), 
WintUe  and  Humphreys  (28), 
Ward-Cousins  (27), and  Bland- 
Sutton  (5),  with  one  or  two 
others,  complete  the  series ; 
they  are  well  known  and  do 
not  call  for  detailed  descrijition  here 
two  facts  are  of  interest 


tumour  also  contained  food  particles  in  the 
form  of  chaff  or  hay. 

Some  of  the  denticles  had  the  usual  char- 
acters of  supernumerary  teeth,  others  were 
fused  together,  \\'hilst  others  again  were  irregular 
in  form.  Absence  of  teeth  from  the  series  was  a 
frequent  feature. 

Various  regions  of  the  mouth  have  been 
involved,  the  teeth  of  the  front  part  chiefly. 
No  history  of  injury  is  given  in  any  of  the  cases, 
nor  has  any  particular  cause  been  given  to 
account  for  them. 

The  chief  clinical  feature  in  cases  of  these 
tumours  appears  to  be  a  swelling  in  the  bone 
with  suppuration,  which  has  led  the  observer 
to  believe  that  he  had  a  case  of  necrosis  of 
the  jaw  to  deal  vrith.,  and  only  at  or  after  the 


One  or 
The  oldest  patient 
was  only  twenty-five  years,  and  the  youngest 
eight  and  a  half  years.  The  older  patients 
presented  themselves  with  the  tumour,  whilst 
the  younger  ages  given  are  at  a  period  when 
the  tumour  first  appeared.  The  age  suggests  the 
date  of  appearance  as  corresponding  with  or 
following  the  period  of  normal  eruption. 

The  maxilla  was  more  frequently  involved 
than  the  mandible ;  they  occurred  in  both 
male  and  female.  Animals  have  suffered  from 
them.  The  classical  case  in  a  Thar,  described 
by  Sir  J.  Bland-Sutton,  is  of  much  interest. 
Each  maxillary  sinus  was  lined  by  a  thick 
fibrous  capsule  containing  about  three  hundred 
calcified  particles  :  some  as  denticles,  others  as 
irregular  masses  of  cementum  and  of  bone ; 
some  were  embedded  in   fibrous  tissue.     The 


A  is  a  geminated  composite  ociontome,  which  was  situated  by  tlio  premolar 
region  of  the  left  side  of  the  mandible.  (Presented  to  the  writer  by 
S.  A.  Knaggs.) 

B  is  a  malformed  tooth  of  a  type  that  is  not  infrequently  found,  where  the 
tooth  has  an  appearance  of  having  been  compressed  laterally,  a  sharp 
overhanging  ridge  separating  the  crown  from  the  root.  The  external 
form  of  these  teeth  may  suggest  an  odontome,  but  their  structure  in 
section  shows  a  comparatively  normal  relationship  between  the  respective 
tissues. 

operation  has  the  nature  of  the  tumour  been 
determined. 

3.  Geminated  Composite  Odontomes 

Greminated  comjjosite  odontomes  are  those 
composite  odontomes  in  which  two  or  more 
malformed  teeth  are  fused  together. 

The  odontomes  in  this  .sub-group  usually 
present  one  or  more  parts  having  some  resem- 
blance to  a  normal  tooth. 

The  gradation  between  these  odontomes  and 
simple  gemination  is  such  that  a  line  of  demarca- 
tion can  be  drawii  with  difficulty.  The  degree 
of  malformation  nuist  l)c  regarded  as  the 
determining  factor.  Specimens  containing 
several  denticles  exist,  but  the  majority  appear 
to  have  arisen  from  two  tooth-germs.  The 
deciding  factor  is  the  presence  of  a  pulp-cavity 
corresponding  with  each  constituent  denticle. 


758 


Tlie  presence  of  a  coronal  and  radicular  part 
of  one  (or  all)  of  the  denticles  is  almost  constant, 
whilst  in  addition  a  calcified  mass,  which  may 
be  so  irregular  as  to  have  the  characteristics  of 
a  complex  composite  odontome,  is  also  found. 

When  the  tissues  are  examined  microscopic- 
ally the  arrangement  is  found  to  be  most 
variable  ;  in  some  parts  the  tissues  appear  to  be 
those  of  a  normal  tooth,  whilst  in  other  parts 
they  are  most  irregular  and  complex. 

These  odontomes  are  found  more  frequently 
in  the  anterior  part  of  the  mouth.  Clinically 
they  do  not  present  any  special  feature,  and  \\ill 


The  arrangement  of  the  tissues  of  the  walls 
resembles  the  normal,  but  the  pulp-chamber 
is  modified  by  the    presence    of   a   small  den- 


Fig.  983. — A  section  of  a  geminated  composite 
odontome.  {From  a  camera  lucida  drawing  by 
D.  P.  Gabell.)  {iluseum  of  the  Royal  Dental 
Hospital  of  London.) 

The  roots  of  tlie  molar  appear  distinct.  The  complex 
calcified  mass  is  closely  attached  to  the  tooth. 

E,  Enamel.  D,  Dentine.  C,  Cementimi.  M,  Irregu- 
larly calcified  material. 

probably  need  attention  only  if  they  are  of  a 
large  size. 

4.    Gestant  Composite  Odontomes 

Gestant  conijiosite  odontomes  are  those  com- 
posite odontomes  in  which  a  denticle  is  contained 
within,  or  surrounded  by,  the  walls  of  a  tooth. 

These  odontomes  have  been  recognized  by 
several  observers.  Ai\  mvestigation  into  their 
mode  of  development  was  made  by  JoseiJh 
Arkovy  (2);  he  speaks  of  them  as  "  odontoma 
interum  "'.  The  tooth  may  or  may  not  present 
an  external  deformity,  but  the  normal  form  is 
usually  altered  in  such  a  manner  as  to  sug- 
gest  an  irregular  arrangement  of    the  tissues. 


Fig.  984. — This  specimen  illustrates  the  gradation 
between  an  odontome  and  a  malformed  tooth. 
On  section  the  tissues  will  be  found  to  be  deranged 
in  the  case  of  an  odontome,  but  if  normally  ar- 
ranged and  only  deformed  externally  it  should 
be  regarded  as  a  malformed  tooth.  Specimens 
such  as  these  are  found  sometimes  to  be  gestant 
composite  odontomes.     (Twice  natural  size.) 

tide,  which  is  variably  placed.  The  small 
denticle  is  usually  composed  of  enamel  and 
dentine.     Various    views   have    been  expressed 


Fig.     985. — Section     showing     a    gestant     composite 

odontome. 
The  specimen  was  thought  to  be  a  common  form  of 

supernumerary    tooth.     The    central    denticle    is 

almost  entirely  composed  of  enamel. 

as  to  their  origin.  They  are  thought  to  arise 
from  two  separate  tooth-germs,  or  by  changes 
occurring  in  a  single  tooth-germ.  They  are 
commonest  in  the  incisor  region.  The  record 
of  cases  is  only  small. 


759 


5.  Enamel  Nodules 

Enamel  nodules  are  enamel -covered  excre- 
scences of  dentine  projecting  from  the  normal 
outline  of  the  dentine  of  a  tooth,  the  nodule 


They  do  not  call  for  treatment,  as  in  most  cases 
they  are  not  recognized  until  the  tooth  is  removed. 

6.  Dilated  Composite  Odontomes 
Dilated  composite  odontomes  are  composite 


/        »». 


\ 


A 


^ 


in  ,1111111-1  iiiilul.  .,. — [Museum  o/  tlic  Royal  Dental  Hospital  of  London.) 
The  first  siicriMuMi  is  \iiy  laiv,  tin-  ikhIuI.'   Ijeing  found  on  a  mandibular  tooth.     The  foiu-th  specimen  shows 
the  gradation  between  tliese  specimens  and  geminated  composite  odontomes.     (Twice  natural  size.) 


being^separated  from,  or  only  slightly  connected 
with,  the  normal  enamel. 

These  nodules,  sometimes  called  epithelial 
pearls,  have  not  been  included  among  odon- 
tomes recentlj',  altliough  formerly  they  were 
classified  with  them  by  Salter  (22). 

They  occur  in  nearly  all  cases  upon  the  roots 
of  maxillary  molars,  being  situated  most 
commonly  at  the  junction  of  the  roots. 

The  most  frequent  form  consists  of  a  rounded 
enamel-covered  projection  varying  in  size, 
usually  about  that  of  a  puis  head,  although 
they  may  attain  the  size  of  a  f)ea.  They  also 
exist  as  a  tongue  of  enamel  passing  on  to  the 
root  of  the  tooth,  or  connecting  the  nodule  v\ith 
the  enamel  of  the  cro%\n.  Irregular  enamel- 
covered  excrescences  are  sometimes  found, 
generally  in  direct  connection  ^\ith  the  enamel 
of  the  cro\\n,  but  they  are  distinctly  rare.  On 
section  the  nodule  jjrojecting  from  the  normal 
dentine  of  the  tooth  seems  to  consist  of  a  core  of 
dentme,  which,  if  large,  may  contain  a  prolonga- 
tion from  tlie  pulp.  Most  frequently  a  group  of 
irregular  spaces  is  present  in  the  neighbourhood 
of  the  nodule.  The  cap  of  enamel  is  well  marked, 
although  its  structure  is  usually  granular. 

When  an  enamel  nodule  is  examined  in 
section,  the  structure  would  suggest  that  it  has 
been  produced  by  the  tooth -germ  that  has 
formed  the  tooth,  and  not  by  a  process  of 
gemination.  It  would  appear  to  be  due  cither 
to  a  portion  of  the  sheath  of  Hertwig  under- 
going an  enamel-producing  function,  or  to  an 
abnormal  development  of  a  part  of  the  coronal 
portion  of  the  enamel-organ. 


odontomes   that   have   the   form   of  a  dilated 
tooth  containing  a  hollow  or  depression. 

Considerable  variation  exists  among  the 
specimens  included  in  this  sub-group,  but  they 
all    possess    certain     common    characteristics. 


Fig.  987. — A  dilated  composite  udunlunie  occupying  the 
position  of  the  mandibular  premolars.  The  illustra- 
tion is  from  a  model  with  the  specimen  in  situ.  It 
is  the  globular  fonn  of  dilated  coinposito  odontome. 

They  have  some  resemblance  to  a  normal  tooth 
in  that  they  present  a  coronal  portion  covered 
by  enamel,  and  a  radicular  portion.  They  have 
an  appearance  of  dilatation,  which  may  involve 
the  crown,  and  hi  almost  all  cases  involves  the 
root.  Also,  roughly  corresponding  with  the 
apparent  dilatation,  the  walls  enclose  a  hollow  or 
depression.  The  group  known  as  "  Kadicular 
Odontomes  "  of  former  classifications,  comprises 


760 


those  where  the  radicular  portion  of  the  odon- 
tome  alone  presents  the  dilated  appearance. 

One  type  of  this  sub-group  shows  a  coronal 
portion,  nuich  larger  than  the  normal  crown  of 
a   tooth,    with   the   central   depression  leading 


Fig.  988. —  A  dilated  composite  odontome  showing  the 
thin  walls  (which  contain  the  pulp-channels), 
and  the  hollow  often  presenting  patches  of 
enamel,  and  containing  irregularly  calcified 
material.  This  specimen  was  not  solid  with 
calcified  tissue,  but  probably  contained  soft 
tissue,  which  had  become  infected ;  for  when 
fractured  at  the  operation  an  exceedingly  foul 
odour  was  emitted.  {Pr&senled  to  the  author  by 
T.  C.  Dykes.) 

into  a  large  hollow  situated  within  the  walls  of 
the  odontome.  Caries  has  involved  nearly  all 
the  specimens  described.  Enamel  may  be 
found  witliin  the  hollow,  and  a  coarse  cementum- 
like  tissue  may  fill  a  large  part  of  it.  The  roots 
are  usually  stunted  and  indistinct.  The  whole 
odontome  has  a  flattened  globular  appearance, 
the  longest  diameter  being  from  side  to  side. 

A  somewhat  similar  type  occurs  where  the 
root  portion  is  more  developed  and  the  ' '  dilata- 
tion "  extends  into  it.  The  longest  axis  is  usu- 
aDy  in  the  vertical  direction  ;  the  whole  tumour 
presents  a  more  or  less  fusiform  appearance. 
The  walls  surrounding  the  hollow  are  usually 
markedly  thin  ;  they  contain  a  flat  pulp-cavity, 
which  is  obliterated  in  places.  Foramina,  a 
definite  slit  or  a  large  opening,  may  be  found 
where  the  pulp-cavity  opens  in  the  apical  region. 

Another  type  exists  in  which  the  crown 
resembles  a  normal  tooth  ^\•hilst  the  radicular 
portion  (radicular  odontome)  presents  a  marked 
dilation,  in  some  cases  reaching  considerable 
dimensions.  A  root  resembling  that  of  a  normal 
tooth  may  be  found  embedded,  forming  part 
of  the  odontome,  but  the  greater  part  of  the 
odontome  consists  of  what  has  been  described 
as  a  "dilated  fang,"  the  diameter  increasing 
from  the  neck  towards  the  base.  They  appear 
to  resemble  the  type  described  above,  the 
foramina  for  the  pulp  being  found  at  the  margin 
of  the  depression,  which  in  this  type  is  present 
at  the  base,  altliough  often  partially  obliterated 
by  secondary  calcified  deposits. 


Some  curious  specimens,  which  appear  to 
belong  to  this  sub-group,  have  the  appearance  of 
having  developed  only  a  part  of  the  wall  that 
encloses  the  depression.  They  show  a  shghtly 
curved,  flattened  root,  which  does  not  continue 
the  axis  of  the  crown,  but  is  placed  to  one  side  ; 
upon  the  hollow  aspect  of  the  root  a  patch  of 
enamel  may  be  found,  with  a  central  depression 
from  which  a  fine  channel  passes  into  the  tooth 
substance,  usually  towards  the  crown. 

The  depression  or  hollow  may  have  patches 
of  enamel  or  cementum  upon  the  dentine  wall, 
whilst  a  quantity  of  irregularly  calcified  vascular 
tissue  may  occupy  a  considerable  part  of  the 
depression  or  hollow.  Sections  of  these  speci- 
mens have  been  cut,  but  little  is  kno-wn  of  their 
minute  structure,  and  nothing  of  their  mode  of 
production. 


Fig.  989.  —  Dilated  composiU'  namitumo  (radicular 
odontome  of  older  classifications).  Specimen  in 
possession  of  J.  G.  Turner,  who  has  no  history  of 
the  case.  The  crown  is  well-developed  and  appears 
to  be  that  of  a  mandibular  molar ;  the  radicular 
portion  presents  a  calcified  mass,  with  a  hollow 
at  the  base  apparently  partly  filled  by  secondary 
calcified  tissue. 

The  removal  of  the  odontome  is  indicated  in 
most  cases. 

III.— CONNECTIVE    TISSUE    ODONTOMES 

This  group  comprises  those  odontomes  that 
arise  only  from  the  dental  tissues  of  meso- 
dermic  origin.  The  classification  of  odontomes 
adopted  by  Sir  J.  Bland-Sutton  was  deter- 
mined by  the  j)art  of  the  developing  tooth  that 
under\\'ent  aberration.  The  two  groups  already 
described  are  due  to  aberration  of  the  enamel- 


761 


organ,  and  although  the  second  group  contains 
a  tissue  of  mesodermic  origin,  its  develojament 
is  dependent  upon  that  of  the  enamel-organ. 
The  present  group  is  due  to  aberration  in  deve- 
lopment  of  the  follicle,  and  might  have  been 


Fig.  990. — Section  of  a  dilated  composite  odontoine. 
(From  a  camera  hicida  drawing  by  D.  P.  Gabell.) 
[Mtiseum  of  the  Royal  Dental  Hospital  of  London.) 

E,  Enamel.  D,  Dentine  (piilp-channels  internal  to 
point  indicated).  P,  pulp-channels.  The  hollow 
of  tlie  odontoma  contained  irregularly  calcified 
material. 

described  as  "follicular  odontomes  "  if  this 
term  had  not  been  used  formerly  for  dentigerous 
cysts.  The  name  "  connective  tissue  odon- 
tomes "  introduced  by  the  Committee  of  the 
British  Dental  Association  appears  to  be  suffi- 
ciently accurate  and  comprehensive. 

As  these  odontomes  are  not  due  to  aberrations 
of  the  enamel-organ,  they  do  not  contain  either 
enamel  or  dentine.  Some  specimens  that  are 
described  as  fibrous  odontomes  and  cementomes, 
and  must,  as  far  as  present  knowledge  goes,  be 
included  among  odontomes,  contain  teeth  that 
show  a  normal  development  of  enamel  and 
dentine,  whilst  the  tissues  derived  from  the 
follicles  have  undergone  aberration. 

The  group  Connective  Tissue  Odontomes  con- 
tains two  sub-groups  and  possibly  a  third — 

1.  Fibrous  Odontomes. 

2.  Cementomes. 
(Sarcomatous  Odontomes.) 

It  is  possible  that  each  of  the  sub-groups 
may  cease  to  be  regarded  as  true  odontomes 


when  their  aetiology  is  definitely  established. 
Both  fibrous  odontomes  and  cementomes  are 
kno^^•n  to  occur  as  the  direct  result  of  patho- 
logical changes,  and  this  may  be  said  to  apply 
to  the  majority  of  the  small  odontomes.  The 
cementomes,  which  attain  an  enormous  size, 
particularly  in  horses,  have  only  been  examined 
in  a  relatively  small  part,  so  that  it  is  conceiv- 
able that  dental  tissues  other  than  cementum 
might  be  present,  but  undetected  ;  should  this 
be  so  they  would  belong  to  the  second  main 
group — comjjosite  odontomes.  The  majority 
of  these  odontomes  have  occurred  in  animals. 

1.  Fibrous  Odontomes 

Fibrous  odontomes  are  odontomes  consisting 
of  an  overgrowth  of  the  fibrous  tissue  of  a 
tooth-sac. 

Almost  all  of  the  odontomes  belonging  to  this 
sub-group  have  been  described  by  Sir  J.  Bland- 
Sutton.  They  are  found  chiefly  in  animals  and 
they  are  said  to  occur  in  man.  Subjects  from 
whom  specimens  of  these  tumours  have  been 
obtained  have  suffered  from  rickets,  and  m 
consequence  the  exce.osive  formation  of  fibrous 
tissue  has  been  regarded  as  merely  patho- 
logical. A  tooth  more  or  less  completely 
developed  is  usually  present  and  surrounded 
completely  by  the  fibrous  tissue.  The  odon- 
tome  is  composed  of  concentric  layers  of  white 
fibrous  connective  tissue,  ^hich  may  show 
sporadic  calcification,  and  is  said  at  times  to 
undergo  conversion  into  cementum,  producing  a 
cementome.  The  few  cases  described  are  to  be 
found  in  papers  published  by  Sir  J.  Bland-Sutton. 

2.  Cementomes 

Cementomes  are  odontomes  composed  of 
cementum.  If  another  dental  tissue  is  present 
the  tissues  are  normally  arranged  \\itli  regard 
to  one  another. 

Two  modes  of  origin  have  been  attributed  to 
these  odontomes,  the  one  in  which  an  excessive 
development  of  cementum  takes  place,  and  the 
other  in  which  calcification  of  a  fibrous  odon- 
tome  occurs.  The  condition  commonly  known 
as  exostosis  of  a  tooth,  where  a  great  increase 
of  cementum  results  from  local  pathological 
changes,  is  sometimes  so  marked  that  it  cannot 
be  distinguished  from  a  true  cementome,  and 
some  specimens  described  as  cementomes  are, 
it  must  be  admitted,  really  the  result  of  a 
formation  of  cementum  due  to  irritation. 

Apart  from  these  specimens  showing  normal 
teeth  with  an  excessive  formation  of  cementum 
upon  the  roots,  there  occur  huge  calcified 
masses  weighing  several  pounds.  The  surface 
of  these  tumours  presents  a  rounded  outline 
with  pits  and  depressions.  The  structure  of 
the  odontome  cannot  be  determined  without  a 
microscopical  section  being  made.  Those  odon- 
tomes  not    comiected    with    otherwise    normal 


762 


teeth  show  a  highly  vascular  tissue,  in  wliich  the 
vascular  spaces  are  very  irregular  whilst  the 
calcified  tissue  is  more  or  less  imperfect.  Those 
associated  with  a  tooth  that  is  developed  show 
a  concentric  or  laminated  arrangement  resulting 
from  the  deposition  of  tissues  in  layers ;  vas- 
cularity is  not  marked,  but  the  lucunae  are 
numerous  and  markedly  branched. 

Very  little  is  known  of  the  clmical  course  of 

these  tumours ;    a   dull   pain   may   be   present 

when   proliferation   is   occurring,   and   removal 

'  may    be    necessary.     Liflammatory   symptoms 

with  suppuration  may  occur. 

Composite  Embryoplaslic  Odontomes 

Odontomes  called  by  Sir  Frederic  Eve  (11) 
"  Composite  Embryoplastic  Odontomes  "  have 
been  described  only  by  him.  The  cases  recorded 
are  too  few,  and  their  true  origin  too  uncertain, 
defuiitely  to  establish  this  sub-group.  The  cases 
consisted  of  sarcomata  with  an  epithelial  tissue 
similar  to  that  found  in  nuiltilocular  cysts. 
Further  investigation  of  these  tumours  should 
prove  to  be  of  great  interest. 

THE  DIAGNOSIS  OF  ODONTOMES 

It  is  necessary  in  discussing  the  diagnosis  of 
odontomes  that  they  should  be  distinguished 
from  one  another,  from  certain  conditions 
arising  in  connection  mth  the  teeth,  from 
tumours  connected  with  or  arising  in  the  jaws, 
and  from  certain  inflammatory  conditions. 

For  convenience  the  clinical  appearances  of 
odontomes  may  be  considered  in  three  stages — 

1.  Wlien  the  bone  jJresents  a  swelling. 

2.  \Mien    the    bone    is    destroyed    over    the 

odontome,  so  that  a  cystic  swelling  can 
be  detected  or  a  calcified  mass  recognized. 

3.  When  infection  of  the  tissues  has  resulted. 
All  odontomes  arise  within  the  bone  of  the 

jaw,  and  therefore  in  all  cases  the  tumour  is 
definitely  associated  with  the  bone.  Pain  is 
rarely  produced  by  any  form  of  odontome  un- 
less infection  of  the  tissues  has  supervened. 

All  the  epithehal  odontomes  are  cystic 
tumours  when  they  can  be  recognized  clinically. 
The  bone  presents  a  globular  swelhng,  usually 
involving  the  outer  alveolar  plate.  The  glo- 
bular nature,  resulting  from  the  presence  of 
fluid,  which  will  cause  an  equal  pressure  in  all 
directions,  is  a  feature  of  the  greatest  signifi- 
cance. At  first  the  cyst  is  covered  by  the  bone 
and  overlying  tissues;  later  the  bony  covering 
is  imperfect  and  fluctuation  can  be  obtained 
over  the  cyst,  the  soft  tissues  continuing  to 
form  a  covering  unless  the  cyst  is  perforated 
as  a  result  of  injury  or  infection. 

Each  of  the  three  types  of  epithehal  odontome 
can  bo  recognized  by  the  period  at  which  it 
occurs,  the  length  of  time  it  has  been  present,  the 
particular  part  of  the  bone  involved,  the  con- 


dition and  number  of  the  teeth  present,  the 
external  conformation  of  the  tumour,  and  the 
conditions  found  upon  taking  a  radiograph. 

Multilocular  cysts  occur  at  any  period  of  Ufe ; 
dentigerous  cysts  appear  a  little  later  than  the 
normal  period  of  eruption  of  the  particular 
tooth  involved ;  dental  cysts  usuaUy  are  found 
in  adults. 

The  rate  of  development  is  slow  in  a  multi- 
locular cyst,  whilst  it  is  most  rapid  in  a  denti- 
gerous cyst ;  both  multilocular  and  dental  cysts 
may  have  been  noticed  by  the  patient  for  a 
considerable  time  before  coming  under  the 
care  of  the  surgeon. 

The  position  in  the  bone  at  which  one  of 
these  cysts  arises  varies ;  in  the  multilocular 
variety  it  may  arise  nearer  the  alveolar  margin 
than  is  the  case  with  either  of  the  other 
forms ;  in  some  cases  the  body  of  the  bone 
becomes  extensively  involved  even  if  the  origin 
is  high  in  the  alveolar  process,  but  the  latter 
is  always  affected.  Dentigerous  cysts  are  rela- 
tively the  most  deeply  situated ;  this  may  be 
the  more  apparent  because  the  bone  develop- 
ment is  incomplete  when  they  occur.  Marked 
changes  in  the  body  of  the  bone  may  be  present 
without  involving  the  alveolar  process,  as  the 
tooth  with  which  the  cyst  is  connected  is  nearly 
always  deeply  situated. 

Dental  cysts  arise  in  the  majority  of  cases  at 
the  level  of  the  roots  of  the  teeth,  and  at  a  time 
when  the  alveolar  process  is  well  developed; 
in  almost  all  cases  the  outer  alveolar  plate  is 
affected  to  a  greater  extent  than  the  imier ; 
the  other  two  types  chiefly  affect  the  outer 
plate,  but  involve  the  inner  plate  and  other 
parts  to  a  greater  degree  than  in  the  case  of  a 
dental  cyst. 

The  absence  of  a  tooth  from  the  series  is 
constant  with  dentigerous  cysts,  unless  it  is 
associated  with  a  supernumerary  tooth.  With 
multilocular  cysts  a  tooth  may  be  absent,  but 
of  the  recorded  cases,  when  the  patient  came 
under  observation  this  factor  was  not  of  much 
value,  as  the  series  was  generally  incomplete. 
The  presence  of  carious  teeth  is  most  common 
in  cases  of  dental  cysts,  and  is  regarded  by  some 
observers  as  an  almost  essential  factor. 

The  conformation  of  the  tumour  may  lie  con- 
clusive in  cases  of  multilocular  cysts,  the  outline 
of  several  cystic  cavities  being  quite  distinctive. 
The  dentigerous  and  dental  cysts  present  a 
rounded  outline,  indicating  a  single  cyst. 

A  radiograph  may  supply  convincing  evidence 
of  several  bony  cavities  in  a  multilocular  cyst, 
or  the  presence  of  a  tooth  in  a  dentigerous  cyst. 

Infection  of  any  of  these  cysts  may  occur, 
but  it  is  not  frequent  in  the  multilocular  form 
and  is  most  common  in  dental  cysts. 

Wlien  infection  is  established  the  changes  may 
be  considerable,  so  that  diagnosis  from  other 
inflammatory  conditions  may  be  difficult,  and 


763 


the   chronic    inflammatory   changes    may    give 
rise  to  an  appearance  of  a  malignant  tumour. 

The  destruction  of  tissue  may  be  considerable, 
when  necrosis  of  the  bone  is  likely  to  occur, 
but  the  sloughing  of  the  surface  tissues  of  the 
cyst  may  be  sufficient  to  provide  drainage. 
When  drainage  is  imperfect,  several  sinuses 
may  be  found  perforating  the  bone  and  soft 
tissues.  The  presence  of  a  cavity  within  the 
bone  in  all  the  various  states  resulting  from 
infection  is  easily  determined ;  the  chief  diffi- 
culty in  the  maxilla  may  be  to  decide  whether 
the  maxillary  sinus  is  involved  directly  or  the 
floor  pushed  up.  The  point  is  easily  determined 
if  the  fluid  will  pass  into  the  nose. 

The  differential  diagnosis  is  best  dealt  with 
by  a  short  account  of  the  conditions  for  which 
the  different  odontomes  may  be  mistaken. 

The  composite  odontomes  present  typical 
conditions,  many  of  which  can  hardly  lie 
regarded  as  of  much  clinical  importance.  The 
small  calcified  odontomes  usually  undergo 
eruption  in  a  manner  similar  to  normal  teeth, 
but  those  of  large  size  remain  deeply  situated 
and  undergo  a  process  of  denudation  only, 
rather  than  a  complete  eniption. 

The  particular  type  of  calcified  odontoma  is 
of  less  importance  than  the  size  and  form  it 
possesses.  Those  having  a  developed  crown 
resemble  closely  in  eruption  the  normal  teeth, 
whilst  those  without  any  resemblance  to  a 
tooth,  particularly  if  they  are  large,  remain 
deeji  in  the  substance  of  the  bone. 

The  larger  number  therefore  of  the  calcified 
odontomes  have  no  clinical  significance.  The 
smaller  ones,  if  unerupted,  may  need  to  be 
distinguished  from  unerupted  teeth,  or  other 
conditions  in  which  a  tooth  is  absent  from  the 
series. 

A  larger  calcified  odontome  gives  rise  to  a 
swelling,  which  usually  increases  in  size  so 
gradually  that  the  patient  is  rarely  incon- 
venienced by  it.  Deformity  or  difficulty  in 
eating  may  cause  the  patient  to  seek  relief, 
Init  the  establishment  of  inflammation  is  the 
most  frequent  means  of  bringing  the  patient 
under  observation.  Wlien  the  odontome  is 
large  the  bone  shows  a  swelling,  which  at  first 
may  be  difficult  to  distinguish  from  the  other 
tumour  arising  within  the  bone.  Both  the 
iimer  and  outer  alveolar  plates  and  the  body 
of  the  bone  may  be  expanded,  and  the  outline 
is  not  globular  as  with  the  cystic  tumours. 
They  occur  in  young  adults,  rarely  later  than 
at  the  age  of  twenty-five  years,  the  period 
corresponding  more  closely  with  dentigerous 
cysts  than  with  any  other  tumour  of  the  jaws. 
The  nature  of  the  swelling  can  usually  be 
determined  by  taking  a  radiograph.  When 
infection  of  the  surrounding  tissues  takes  jilace, 
the  odontome  can  be  felt  with  a  probe,  even  if 
it   is  not   actually  exposed.     The   presence  of 


necrosed  bone  with  acute  inflammation  may 
cause  the  condition  to  be  regarded  as  one  of 
simple  necrosis,  as  was  the  case  with  most  of 
the  compound  composite  odontomes.  Those 
calcified  odontomes  that  have  attained  to  a 
large  size  have  either  been  situated  in  the 
posterior  part  of  the  body  of  the  mandible,  or  " 
have  extended  into  the  maxillary  sinus  in  the 
maxilla. 

The  condition  most  frequently  mistaken  for 
a  calcified  odontome  is  an  infection  of  the 
tissues  connected  with  a  third  molar,  particu- 
larly in  the  mandible.  Before  an  operation  is 
performed  in  either  case  a  radiograph  should 
be  taken  if  the  tumour  cannot  be  examined 
satisfactorily. 

The  connective  tissue  odontomes  are  rare  in 
man.  Cementomes  resembling  some  of  the 
complex  composite  odontomes  in  possessing  an 
external  formation  of  no  particular  shape,  will 
have  the  same  clinical  characteristics  and  may 
be  distinguished  only  by  a  microscopical 
examination.  Cementomes  that  may  be  re- 
garded as  an  abnormal  degree  of  "  exostosis  " 
are  connected  with  teeth  that  usually  have 
taken  a  normal  position  in  the  dental  arch. 
Tlie  mass  of  cementum  connected  with  these 
teeth  may  involve  neighbouring  teeth,  and  will 
cause  a  distension  of  the  bone  corresponding 
with  the  new  formation.  Fibrous  odontomes 
have  been  found  in  subjects  suftering  from 
rickets. 

Tumours  composed  of  fibrous  tissue  have 
been  described  as  originating  in  the  fibrous 
tissue  of  the  tooth-follicle,  but  other  observers 
have  doubted  this,  even  after  the  tumour  has 
been  removed  and  has  undergone  careful 
examination.  Fibrous  tumours,  although  rare, 
do  occur  in  the  jaws,  but  are  rarely  recognized 
prior  to  an  operation  upon  them. 

Certain  conditions  arising  in  connection  with 
teeth  may  be  mistaken  for  an  odontome.  A 
misplaced,  unerupted  tooth,  giving  rise  to  a 
swelling  upon  the  bone,  may  be  regarded  as 
either  an  early  condition  of  a  dentigerous  cyst 
or  a  calcified  odontome.  The  diagnosis  may  be 
impossible  without  the  aid  of  a  radiograph. 
Reference  has  already  been  made  to  infection 
of  the  tissues  associated  with  an  unerupted 
third  mandibular  molar,  and  a  similar  condition 
may  arise  in  connection  with  any  tooth  that  is 
unerupted.  A  sinus  leading  to  a  structure 
found  upon  examination  with  a  probe  to  be  a 
tooth  substance,  will  indicate  two  or  three 
conditions,  which  may  be  determined  froni  the 
history,  or  only  by  a'radiograph  or  operation. 

A  chronic  osteitis  around  the  apex  of  a  tooth 
due  to  infection  from  a  pulp,  may  give  rise  to 
a  large  nodule  produced  by  the  periodontal 
membrane  over  the  apical  region  of  the  tooth. 
These  nodules  are  usually  found  upon  the  outer 
alveolar  plate,  although  "they  do  occur  on  the 


764 


imier  plate.  Tliey  are  more  likely  to  be  mis- 
taken for  a  "  cementome  "  than  the  other 
forms  of  calcified  odontome.  A  similar  con- 
dition, but  less  regular,  and  corresponding  with 
a  larger  surface  of  the  root — often  over  several 
teeth  and  associated  with  other  indications  of 
the  disease — is  found  in  cases  of  pyorrhoea 
alveolaris.  These  are  less  likely  to  be  mistaken 
unless  the  condition  is  very  marked  over  one 
tooth,  whilst  it  must  be  remembered  that 
large  exostoses  of  the  roots  are  frequently 
found  in  certain  forms  of  this  disease. 

A  condition  that  has  been  mistaken  for  a 
suppurating  dental  cyst  is  a  large  cavity 
situated  in  the  palate  between  the  periosteum 
and  the  bone.  In  one  patient  suppuration 
arising  from  a  lateral  incisor  had  extended 
between  the  periosteum  and  the  bone  almost 
to  the  attachment  of  the  soft  palate,  the  muco- 
periosteum  had  been  bulged  downwards,  new 
bone  had  been  formed,  and  two  sinuses  were 
present  communicating  with  a  cavity  about 
one  inch  deep  and  more  than  one  and  a  half 
inches  long ;  the  original  abscess  had  occurred 
more  than  a  year  previously. 

The  distinction  between  odontomes  and 
tumours  connected  with  the  jaws  may  not  be 
difficult,  but  a  mistake  in  diagnosis  can  easily 
be  made.  Difficulty  may  be  experienced  with 
the  tumours  arising  within  the  bones,  but  they 
are  not  of  frequent  occurrence,  the  most  com- 
mon being  the  central  or  myeloid  sarcoma 
(myeloma).  It  is  necessary  to  remember  that 
tumours  commencing  in  the  maxillary  sinus 
may  extend  into  the  maxillary  bone  and  appear 
as  tumours  within  the  bone.  New  growths 
arising  in  the  muco-periosteuni  are  less  likely 
to  be  mistaken  for  odontomes,  although  the 
condition  may  not  be  easy  to  determine. 

There  is  considerable  difference  between  the 
tumours  connected  with  the  maxiUae  and  those 
coimected  with  the  mandible,  as  the  former 
include  those  associated  with  the  maxillary 
sinus  and  the  palate.  Cysts,  other  than  epi- 
thelial odontomes,  are  exceedingly  rare,  and 
do  not  call  for  detailed  description.  Dermoid 
cysts  have  been  described  as  occurring  in  the 
floor  of  the  mouth  immediately  behind  the 
incisor  region  of  the  mandible,  and  one  was 
associated  with  the  ascending  ramus.  Serous 
cysts  situated  in  the  ascending  ramus  of  the 
mandible  have  been  recorded.  A  condition 
arising  in  the  maxillary  sinus  known  as  "  cystic 
disease  of  the  antrum  "  is  also  described.  The 
innocent  tumours  said  to  occur  consist  of 
Papilloma,  Angeioma,  Lipoma,  Adenoma, 
Myxoma,  Fibroma,  Chondroma,  Osteoma,  and 
Myeloma  (myeloid  sarcoma) ;  some  of  these  are 
extremely  rare  and  might  almost  be  omitted. 

Papilloma  occurs  upon  the  gum  and  upon 
the  palate  ;  it  is  definitely  connected  with  the 
mucous  membrane. 


Angeioma  may  occur  in  the  gums,  and  is 
most  frequently  associated  with  a  similar  affec- 
tion of  the  neighbouring  mucous  membranes ; 
the  vascular  nature  of  the  tumour  is  not  likely 
to  be  mistaken. 

Only  one  or  two  cases  of  lipoma  have  been 
described. 

A  form  of  adenoma  occurs  in  the  palate,  but 
the  term  has  been  used  for  tumours  of  the 
palate  that  are  not  truly  adenomatous. 

Myxoma  has  been  described  but  is  very  rare ; 
it  is  said  to  occur  in  the  maxillary  sinus  and 
the  palate,  and  has  also  been  found  on  one 
occasion  in  the  mandible. 

A  fibroma  is  perhaps  the  commonest  of  the 
innocent  tumours ;  it  occurs  frequently  as  a 
"  fibrous  epulis  "  arising  from  the  periosteum, 
usually  at  the  upper  margin  of  a  tooth-socket ; 
it  is  a  firm  tumour  and  is  attached  by  a  more 
or  less  narrow  pedicle.  In  the  palate  it  may 
attain  a  considerable  size,  becoming  moulded 
to  the  hollow  of  the  palatal  arch. 

Other  types  of  fibroma  are  found,  but  are 
distinctly  rare.  A  periosteal  fibroma  that  does 
not  present  as  a  pedunculated  tumour  as  de- 
scribed above,  but  is  found  as  a  diffuse  swelling 
situated  upon  the  bone,  occurs  usually  on  the 
alveolus ;  it  is  of  slow  growth  and  may  attain 
to  a  considerable  size.  Histologically  these 
tumours  are  found  to  be  fibromata,  but  the 
possibility  of  a  sarcoma  of  very  low  malignancy 
must  be  borne  in  mind.  A  similar  form  as  a 
diffuse  condition,  where  almost  the  whole  of 
the  alveolar  processes  may  be  involved,  occurs 
both  in  children  and  adults ;  in  the  latter  an 
infective  process  is  nearly  always  associated. 
Fibromata  arising  within  the  bone  are  also 
found.  They  occur  in  the  maxillary  sinus 
leading  to  the  distension  of  that  cavity.  They 
also  occur  in  the  mandible,  probably  as  false 
neuromata  upon  the  inferior  alveolar  nerve 
or  its  branches,  and  they  have  been  described 
as  originating  from  the  fibrous  tissue  witliin 
the  bone.  Great  difference  of  opinion  has  been 
expressed  as  to  the  origin  of  these  "  endosteal 
fibromata ".  Broca  and  Bland-Sutton  have 
regarded  some  of  them  as  fibrous  odontomes. 
They  constitute  very  slowly  growing  tumours, 
cause  expansion  of  the  jaw,  and  are  usually 
diagnosed  at  the  operation,  although  a  radio- 
graph may  suggest  their  nature.  The  rarity  of 
them  renders  a  correct  diagnosis  improbable. 

Chondromata  were  described  by  Christopher 
Heath  (14),  and  are  mentioned  in  all  classifica- 
tions of  tumours  of  the  jaw,  l;ut  they  nuist  be 
exceedingly  rare.  There  does  not  appear  to  be 
any  recent  record  of  this  tumour,  and  it  is 
possible  that  the  majority  of  those  formerly 
described  were  either  endothehomata  or 
sarcomata. 

0.steoma  of  the  jaws  is  not  common.  It  may 
occur  upon  the  mandible  in  the  region  of  the 


765 


angle,  where  it  may  be  symmetrical.  Perhaps 
the  most  common  form  of  osteoma,  if  it  can  be 
so  described,  is  the  bony  nodule  found  upon 
the  imier  aspect  of  the  mandil)lc  below  the 
level  of  the  first  premolars ;  they  are  usually 
symmetrical.  It  has  been  suggested  that  they 
are  produced  by  the  action  of  the  mylo-hyoid 
muscles ;  they  arc  frequently  found  in  v,e\l- 
devcloped  jaws.  The  periostitie  nodules  found 
upon  the  alveolar  plates,  particularly  the  outer, 
have  already  been  referred  to.  The  marked 
deposit  of  bone  that  takes  place  upon  the 
anterior  surface  of  the  maxillary  bones  in  cases 
of  leontiasis  ossea  is  more  or  less  symmetrical, 
and  although  at  first  it  may  be  difficult  to 
diagnose,  is  quite  characteristic  in  the  later 
stages.  An  osteo-sarcoma  may  be  mistaken 
for  an  osteoma. 

Myeloma  (myeloid  sarcoma  or  central 
sarcoma)  is  to  be  regarded  as  an  innocent 
tumour,  although  it  is  frequently  described 
among  the  sarcomata.  There  appear  to  be 
gradation  types  from  the  form  that  is  quite 
innocent  to  those  definitely  sarcomatous. 
Apart  from  the  odontomes  it  (or  a  fibroma)  is 
the  commonest  tumour  occurring  in  the  jaws. 
It  arises  within  the  bone,  and  if  teeth  are 
present  usually  reaches  the  surface  through  a 
tooth  socket,  appearing  by  the  side  of  the  tooth 
or  causing  it  to  become  loose  and  to  be  lost ; 
when  no  tooth  is  present  it  appears  as  a  rounded 
swelling  between  the  alveolar  plates.  Li  some 
cases  it  appears  to  arise  more  in  the  substance 
of  the  compact  bone  than  centrally,  and  then 
presents  as  a  swelling  beneath  the  periosteum. 
When  the  tumour  has  perforated  the  mucous 
membrane  it  presents  a  characteristic  appear- 
ance :  it  is  obviously  coming  horn,  within  the 
bone;  the  usual  description  is  that  it  has  a 
maroon  colour,  but  it  is  variable,  often  being 
blotchy  ;  it  is  usually  soft  and  vascular,  some- 
times pulsating.  The  tumour  may.be  quite 
large  without  perforating  the  nuicous  membrane, 
and  may  involve  a  large  part  of  the  jaw ;  in 
the  maxilla  the  maxillary  sinus  may  be  exten- 
sively invaded.  It  does  not  cause  pain.  A 
radiograph  shows  destruction  of  bone,  but  with- 
out sharp  definition  as  in  the  case  of  a  cyst. 

An  error  in  diagnosis  has  frequently  been 
made  between  this  tumour  and  a  dental  cyst. 
Wlien  a  myeloma  projects  between  the  alveolar 
plates,  the  tooth  or  teeth  having  been  lost,  the 
diagnosis  may  be  difficult.  It  often  fluctuates, 
but  is  rather  oval  than  globular  in  form,  as  it 
extends  more  easily  between  the  alveolar  plates  ; 
the  latter  are  destroyed,  new  bone  being  induced 
beneath  the  periosteum,  luit  the  inner  and 
outer  plates  are  more  equally  affected  than  is 
usual  with  a  dental  cyst.  Wlien  the  tumour  is 
large,  the  surface  is  less  regular  than  that  of  a 
dental  cyst.  The  difference  seen  in  radio- 
graphs already  referred  to  is  distinctive. 


Endothelioma  is  a  form  of  tumour  that  has 
not  long  been  recognized,  and  probabh'  accounts 
for  the  descrijitions  found  of  certain  tumours 
that  do  not  appear  to  belong  to  the  particular 
group  to  which  they  were  allotted.  Sir  J. 
Bland-Sutton  has  stated  that  many  of  the 
tumours  called  nniltilocular  cysts  were  really 
endothcliomata,  and  it  is  known  that  these 
tumours  have  been  mistaken  for  chondromata. 
An  endothelioma  is  a  tumour  arising  from  the 
endothelial  cells,  chiefly  of  the  blood  or  lymph 
vascular  system.  Tliey  appear  to  bear  an 
intermediate  position  between  the  innocent 
and  mafignant  tumours.  Some  doubt  exists 
as  to  their  true  nature,  as  different  opimons 
are  expressed  by  pathologists.  They  do  not 
always  appear  to  consist  of  endothelial  cells 
alone,  but  present  a  mixed  cell  growth.  They 
are  knowii  to  arise  in  the  gums,  and  also 
probably  occur  wthin  the  bones.  They  are 
of  slow  growth,  generally  displace  the  tissues 
rather  than  infiltrate  them  as  a  malignant 
growth  does,  and  do  not  give  rise  to  secondary 
foci  in  the  lymph  glands.  Their  nature  is  not 
usually  recognized  until  a  microscopic  section 
is  made.  Little  can  be  said  with  regard  to 
their  diagnosis,  but  they  will  probably  undergo 
removal,  having  been  mistaken  for  a  sarcoma 
or  fibroma. 

The  mafignant  tumours  connected  \\ith  the 
jaws  may  be  either  carcinomata  or  sarcomata. 

The  carcinomata  are  the  more  common  as 
they  occur  frequently  in  the  neighbouring  struc- 
tures and  involve  the  jaw  secondarily ;  apart 
from  these,  carcinoma  may  arise  in  the  gums 
or  in  the  maxillary  sinus,  and  a  rare  form 
known  as  "  burrowing  epithelioma  "  is  said 
to  originate  in  the  remains  of  the  dental  epi- 
thelium. A  secondary  gro\\-th  also  maj^  be 
found  in  the  jaw. 

A  carcinoma  invading  the  jaw  from  a  neigh- 
bouring structure  will  be  obvious  in  the  majority 
of  cases;  the  very  hard  infiltrating  growih, 
which  usually  presents  as  a  foul  ulcer  with 
everted  edges,  and  the  presence  of  hard  glandular 
nodules  distinct  from  the  glands  irritated  by  the 
absorption  of  toxic  products,  are  characteristic. 

In  the  mandible,  carcinomata  commencing  at 
the  fraenum,  or  on  the  floor  of  the  mouth  below 
the  third  molar,  most  rapidly  involve  the  jaw ; 
those  arising  in  the  ])arotid  gland  come  early 
into  close  relationship  with  the  ramus.  Limi- 
tation of  movement  is  an  early  symptom,  and 
the  dental  surgeon  may  have  to  determine  that 
this  is  not  of  dental  origin.  The  absence!  of 
expansion  of  the  bone  will  exclude  tlie  presence 
of  an  odontome. 

In  the  maxilla,  carcinonui  eonnnencing  in 
the  palate  is  less  common  than  in  the  floor  of 
the  mouth  ;  the  maxillary  sinus  may  be  involved, 
but  the  nature  of  the  growth  is  sucli  that  it  is 
not  likely  to  be  mistaken  for  a  tumour  of  dental 


766 


origin.  It  must,  however,  be  remembered  that 
the  less  compact  bone  of  the  maxilla  is  more 
easily  infiltrated  by  the  gro\rth  than  that  of  the 
mandible. 

Carcinoma  arising  in  the  gum  will  present 
the  characteristics  of  a  carcinomatous  ulcer,  and 
should  not  be  mistaken  for  a  tumour  expanding 
the  jaw. 

The  maxillary  sinus  may  be  the  seat  of 
carcinoma ;  it  may  be  of  a  cohunnar-cell  or  a 
squamous-cell  variety.  In  either  form  the 
growth  may  cause  a  swelling  upon  the  anterior 
wall,  the  nature  of  which  may  be  difficult  to 
distinguish  at  first,  but  the  growth  will  usually 
be  detected  in  the  nose,  or  infiltration  of  the 
cheek  ^vill  be  found.  The  sweUing  is  associated 
with  the  upper  part  of  the  bone  rather  than 
with  the  alveolar  process. 

BuiTO\\ing  epithelioma,  which  has  involved 
the  maxillary  sinus  in  the  few  cases  recorded, 
has  been  recognized  first  upon  extraction  of  a 
tooth.  A  soft  growth  was  found  attached  to 
the  tooth,  and  upon  examination  proved  to  be 
carcinoma.  The  growth  had  invaded  the 
maxillary  sinus  without  causing  superficial 
changes  in  the  bone  ;  fortunately  tlie  malignancy 
of  these  tumours  appears  to  be  very  low. 

A  secondary  growth  due  to  carcinoma  in 
another  part  of  the  body  may  be  found  in  the 
jaws  ;  certain  carcinomata,  such  as  in  the  lireast, 
are  prone  to  give  rise  to  secondary  deposits  in 
the  bones.  They  are  not  likely  to  be  of  great 
importance  to  the  dental  surgeon. 

The  sarcomata  are  most  frequently  found  as 
periosteal  tumours ;  they  also  arise  in  the 
maxillary  sinus  and  \rithin  the  substance  of 
the  bone. 

They  occur  as  round -cell,  spindle-cell  and 
mixed-cell  sarcomata.  They  are  also  found  in 
the  form  of  fibro-sarcoma  and  osteo-sarcoma. 

A  rapidly  growing  tumour,  usually  com- 
mencing on  the  body  of  the  bone  rather  than 
the  alveolus,  firm  or  even  hard,  although  less 
so  than  the  bone  itself,  but  situated  upon  the 
bone  and  not  causing  expansion  of  it,  will 
probably  prove  to  be  a  periosteal  sarcoma. 

In  the  maxillary  sinus,  a  sarcoma  gives  rise 
to  sjTuptoms  similar  to  those  of  carcinoma ;  the 
former  is  probably  the  more  frequent,  but  the 
nature  of  the  growth  beyond  its  mahgnancy  is 
often  not  recognized  until  the  operation  is  done 
or  a  microscopical  examination  made. 

Sarcoma  arising  within  the  bone  may  be  of  the 
round-cell  or  spindle-cell  variety,  but  it  is  usually 
of  a  mixed  type  and  may  contain  numerous 
myeloid  cells. '  It  is  certainly  rare.  The  growth 
that  recurs  after  an  operation  is  usually  more 
malignant  than  the  primary  growth. 

In  concluding  tliis  article  upon  odontomes, 
it  may  be  well  to  emphasize  the  importance  of 
recognizing  the  nature  of  sweUings  that  may 


appear  in  the  jaws.  The  majority  of  odontomes 
and  other  tumours,  particularly  those  of  much 
significance,  are  not  seen  frequently,  but  the 
ojjfJortunity  the  dental  surgeon  has  of  caUing 
attention  to  them  at  an  early  stage  is  so  great 
that  he  should  keep  himself  well  acquainted 
with  the  symptoms  of  import.  Manj-  of  the 
tumours  described  can  be  dealt  with  by  the 
dental  surgeon,  but  as  regards  those  that  are 
better  in  the  hands  of  the  general  surgeon, 
they  should  be  placed  under  his  care  at  the 
earliest  stage  possible,  in  order  to  give  the 
patient  the  opportunity  of  obtaining  the  best 
possible  results.  In  all  doubtful  cases  it  is 
wise  to  seek  further  advice,  even  should  it 
prove  to  have  been  unnecessary,  rather  than  to 
a^^•ait  more  definite  symptoms. 

W.  W.  J. 

BIBLIOGR.A.PHY 

(1)  Alberran.     Revue  de  Chir.,  1888. 

(2)  Arkovy.     Brit.  Dent.  Jour.,  1883,  Vol.  IX,  p.  372. 

(3)  Bernays.     Medical  Record,  New  York,  July  1885, 

Vol.  XXXVIII,  p.  1. 
(i)  Bland-Suttox,    Sir    .John.     Earliest    Classifica- 
tion.     Trans.  Odonl.  Soc.  1887-8,  Vol.  XX,  p.  34. 

(5)  Blakd-Sutton,   Sir  John.     Trans.   Odont.   Soc, 

1888-9,  Vol.  XV,  p.  185. 

(6)  Bt.and-Sctton,    Sir   John.     Tumours    Innocent 

and  Malignant,  1911,  5th  ed. 

(7)  British  Dental  Associ.ation  Committee.     Re- 

port on  Odontomes,    1914. 

(8)  Broca.      Trans,    in    Review    of    Dental    Surgery, 

1872-3,  1873-1. 

(9)  DOLAMORE    AND     HOPEWELL-S.^IITH.       Brit.     Dent. 

Jour.,  1902,  Vol.  XXIII,  p.  546. 

(10)  Eve,   Sir    Frederic.      Brit.    Med.   Jour.,    1883, 

Vol.  I,  pp.  1,  91,  241,  298. 

(11)  Eve,  Sir    Frederic.      Pathology  of    Treatment 

of   Tumours    of   the   Jaws.     Brit.    Med.    Jour., 
June  29,  1907. 

(12)  F.iLKSON.     Beitrag   zur   Entwickelungsgeschichte 

der  Zalmlage  und  der  Kiefercj-sten,  Konigsberg, 
1878. 

(13)  F.AI.KSOX.     Archives  fiir  Path.  Anat.  imd  Phys., 

Virchow,  1879,  Vols.  LXXVI,  p.  504. 

(14)  He.\th.  Christopher.     Injuries  and  Diseases  of 

the  Jaws,  1894. 

(15)  Hertwig.  Lehrbuch  der  Entwickelungsgeschichte, 

1888. 

(16)  James,  W.   W.   and  Forbes,  J.   G.     Proc.  Roy. 

Soc.  of  Med.  {Odont.  Sec.),  June  1909,  Vol.  II, 
Part  III,  p.  166. 

(17)  James,  W.  \V.     Proc.  Roy.  Soc.  of  Med.  {Odont. 

Soc),  1914,  Vol.  IV,  Part  III,  p.  85. 

(18)  JIalassez.     Archiv.  de  Physiologic,  \SS5,^eTieWX, 

tome  V,  p.  129. 

(19)  Malassez.     Comptes    Rendus    de    la    Societe    de 

Biologic,  1887,  Serie  VIII. 

(20)  Mathias.      Trans.    Odont.    Soc,    1862,    Vol.    Ill 

(old  series),  p.  366. 

(21)  RijsE.     Archil:    fur    Mik.     Anat.,'  Bona,     1891, 

XXXVIII,  p.  456. 

(22)  S-\LTER.     Dental  Surgery  and  Pathology. 

(23)  Tellander.      Tran^.   Odont.  Soc,   1862,  Vol.   Ill 

(old  series),  p.  282. 

(24)  Tomes,  C.     Dental  Surgery,  1897. 

(25)  Turn-er,  J.  G.     Jour.  Brit.  Dent.  Assoc,  1898. 

(26)  Von  Brun.     Archiv.  fiir  Mik-.  Anat..  1887. 

(27)  Ward-Cousins.     Brit.  Med.  Jour.,  1906. 

(28)  WiNDLE    .\ND    Humphreys.       Jour.     Anat.    and 

Phys.,    1887,   Vol.   XXI,  p.   667. 


CHAPTER    LI 

ACTINOMYCOSIS   OR   STREPTOTHRICOSIS 


AcTEs'OMYCOSis  was  the  name  given  to  a 
disease  that  occurs  in  cattle ;  it  was  so  named 
on  account  of  a  characteristic  appearance  under 
the  microscope  of  the  organism  causing  it,  when 
a  radiating  arrangement  of  club-like  bodies  is 
seen.  It  is  now  kno-mi  that  the  club-shaped 
bodies  are  the  result  of  degeneration  ;  they  are 
so  distinctive  that  the  name  actinomyces,  or 
ray -fungus,  was  suggested  for  the  organism.  As 
a  result  of  investigation,  several  varieties  of 
this  organism  have  been  recognized ;  many  have 
been  examined  in  pathological  laboratories,  and 
their  characteristics  recorded. 

This  group  of  organisms  has  been  named  the 
Streptothricheae,  and  is  believed  to  belong  to  the 
mould-fungi  or  hj-phomycetes.  Some  observers 
contend  that  it  should  be  placed  between  the 
fission-fungi  and  the  mould-fungi.  The  term 
actinomyces  is  also  used  for  the  whole  group. 

The  disease  resulting  from  an  infection  by 
an  organism  of  this  group  is  called  Sirepto- 
thricosis  or  Actinomycosis,  and  has  a  sufficiently 
definite  clinical  course  to  be  described  as  a 
specific  disease,  each  particular  organism  pro- 
bably producing  a  variation  in  the  clinical  type 
of  the  disease,  although  at  present  the  know- 
ledge gained  is  most  incomplete. 

The  disease,  as  commonly  seen,  is  marked  l>y 
a  chronic  course,  is  practically  always  localized, 
and  spreads  h)y  direct  extension.  It  is  seen 
most  commonly  in  cattle,  but  also  occurs  in 
other  animals  and  in  man.  It  is  of  rarer 
occurrence  in  England  than  in  America  and  on 
the  Continent. 

In  man,  cases  occur  at  all  ages,  but  the 
majority  are  found  in  young  adults.  Men  are 
affected  more  often  than  women,  one  observer 
giving  the  proportion  as  nearly  three  to  one. 

The  source  of  the  infection  is  not  definitely 
determined.  Much  evidence  has  been  produced 
to  show  that  it  is  due  to  the  presence  of  the 
fungus  upon  grasses,  straw,  and  corn  ;  the  organ- 
ism has  been  artificially  cultivated  from  them, 
and  in  some  cases  particles  of  straw  or  corn 
have  been  found  in  the  diseased  area.  That 
the  oral  cavity  is  the  commonest  seat  of  infec- 
tion, and  that  cattle  are  most  frequently 
affected,  would  support  tliis  view.  Of  recorded 
cases  in  man,  however,  many  patients  had  lived 
entirelv  in  towns,  and  had  not  run  the  risk  of 
infection  from  grasses,  etc. 


It  is  improbable  that  direct  infection  occurs 
from  an  animal  to  other  animals  or  to  man,  as 
infected  animals  have  been  kept  for  a  consider- 
able period  with  uninfected  ones  without 
inducing  the  disease  in  the  latter.  Tliere  is  no 
record  of  a  case  of  infection  of  one  individual  by 
another.  The  disease  can  be  produced  in  animals 
artificially  by  the  introduction  of  the  fungus. 

The  characteristics  of  the  streptotlirix  group 
have  been  investigated  in  the  laboratory,  and 
an  explanation   given    in    some   degree   of   the 


Fig.  931. — Streptothn.x  organiMi.. 
Cultivated  from  a  case  of  actinomycosis  in  a  man. 
The  infection  occurred  in  the  tissues  on  the  buccal 
aspect  of  a  third  mandibular  molar.  T\-pical 
granules  were  foimd  in  the  pus,  which  was  very 
scanty.  The  bone  was  laid  bare,  but  the  cheek 
tissues  chiefly  were  involved. 

various  conditions  found  in  diseased  tissues. 
In  a  case  of  actinomycosis  the  fungus  can  be 
examined  either  as  a  granule  obtained  from  the 
discharge,  or  in  a  piece  of  the  tissue  removed 
from  an  infected  area. 

Under  the  microscope  in  a  stained  specimen 
a  felted  mass  composed  of  numerous  threads  is 
.seen,  which  upon  closer  examination  are  found 
to  1)6  branched,  the  branch  being  produced  by 
a  lateral  outgrowth  and  not  by  a  di\-ision  at 
the  end  of  the  filament.  The  filaments  present 
different  appearances,  some  being  well  stained. 


767 


768 


others  unequally  stained,  or  when  degenerated, 
unstained.  The  filaments  may  be  broken  into 
longer  or  shorter  fragments  ;  their  terminations 
may  be  pointed,  rounded,  or  club-shaped. 

If  an  examination  is  made  of  the  discharge 
without  using  any  stain,  rounded  masses 
refracting  light  and  showing  a  rosette-like 
arrangement  of  clubs  or  rays  may  be  observed, 
or,  where  these  masses  are  broken  up,  granular 
particles  only  will  be  seen. 

Spores  examined  on  a  warm  stage  can  be 
observed  to  form  a  mycelial  mass.  Buds  are 
seen  growing  from  the  spherical  spores  to  form 
threads ;  lateral  branches  grow  from  the 
threads,  and  again  from  the  new  threads 
further  lateral  growths  forming  fresh  threads 
are  produced.  The  continuation  of  this  process 
produces  the  felted  mass  of  intermingling  fila- 


FiG.  992. — Higher  inagnilicatioii  of  organism,  from 
saine  case  as  Fig.  991. 

ments  that  make  up  the  tuft  of  a  well-develoj)ed 
mycelium.  The  mycelium  is  a  rounded  or 
globular  mass  with  a  dense  central  area  and  a 
less  dense  or  loose  peripheral  zone.  The  ter- 
mination of  the  filaments  may  be  pointed, 
rounded,  or  bulbous,  either  as  globules  or 
club-like  enlargements.  The  mycelium  consists 
of  threads,  which  are  more  or  less  uniform  in 
appearance  ;  but  later  separation  into  segments 
occurs  and  spores  are  produced.  With  seg- 
mentation there  is  also  degeneration,  which 
occurs  at  certain  but  not  regular  intervals  ;  the 
staining  of  the  filaments  is  irregular,  and  the 
degenerated  portions  do  not  retain  the  stain 
when  Gram's  method  is  used,  or  only  shghtly 
with  basic  aniline  dyes.  Following  segment- 
ation, the  degenerated  portions  disappear,  leav- 
ing rods  that  vary  in  length,  and  that  appear  as 


straight,  curved,  or  even  twisted  remnants 
of  the  threads.  A  few  lateral  branches  may  be 
seen,  and  a  nodular  or  beaded  appearance  is 
often  present.  (It  is  possible  that  these  rods 
are  capable  of  giving  rise  to  fresh  lateral  buds 
and  a  new  mycelium  without  spore -formation.) 
Coincidently  with  segmentation,  indication  of 
chain  sf)orulation  may  take  place  ;  the  terminal 
portions  of  the  filaments  and  their  lateral 
branches  assume  a  closely  beaded  appearance ; 
where  the  segmentation  j)rocess  is  more  regular 
and  occurs  at  close  intervals,  each  short  segment 
becontes  ovoid  or  spherical ;  the  degenerated 
part  disappears,  leaving  spores,  which  may  be 
in  chains,  and  possibly  indistinguishable  from 
streptococci  or  similar  organisms. 

The  process  of  growth  is  therefore  by  lateral 
budding  from  a  filament,  which  may  be  in 
quite  short  segments,  and  from  spores.  The 
degenerated  rods  and  clubs  often  <30ntain  a 
central  filament,  which  stains.  True  clubs  are 
practically  never  seen  in  culture  specimens. 

Gram's  method  is  most  commonly  used  for 
staining  ;  eosin  and  methylene  blue  or  carbol- 
fuchsin  are  also  employed ;  some  varieties 
resemble  the  tubercle  bacillus  in  being  acid-fast. 
The  fungus  can  be  cultivated  upon  agar-agar  as 
elevated  greyish-white  colonies,  or  in  broth  as 
greyish  white  clumps  or  granules.  These  fungi 
differ  in  their  cultural  features,  some  being 
aerobic,  others  anaerobic. 

Wien  the  tissues  are  infected  by  this  parasite 
they  vary  in  appearance  according  to  whether 
it  is  simple,  or  complicated  by  a  secondary 
infection.  If  a  pyogenic  organism  is  present 
the  destruction  of  tissue  and  the  amount  of 
pus  is  considerably  increased,  and  the  clinical 
picture  possibly  masked.  In  the  case  of  a 
simple  infection  very  little  pus  may  be  produced, 
the  tissues  undergoing  chronic  inflammatory 
changes  with  the  production  of  a  large  amount 
of  granulation  tissue ;  the  surrounding  tissues 
show  a  smaU-celled  infiltration  ^^■ith  the  pro- 
duction of  endothelial  (epithelioid)  cells  and 
occasionally  giant-cells,  not  unlike  the  tissue 
associated  with  tuberculous  infections ;  some 
organized  fibrous  tissue  will  be  seen  in  cases  of 
long  standing.  In  section  the  tissue  shows  a 
honeycombed  appearance,  the  alveoli  corre- 
sponding with  jjoints  of  growth  of  the  fungus 
where  destruction  of  tissue  has  taken  place.  The 
amount  of  tissue  broken  down  to  form  pus  may 
be  very  small,  the  absence  of  pus,  where  a 
secondary  infection  has  not  occurred,  being  a 
somewhat  characteristic  clinical  feature.  The 
streptothrix  organism  alone  has  been  thought 
to  be  capable  of  causing  supj)uration. 

Clinically  the  conditions  will  vary  with  the 
part  of  the  body  affected.  The  parasite  gains 
access  by  the  alimentary  or  respiratory  tract, 
cases  occurring  most  commonly  in  the  mouth, 


769 


and  also  in  the  appendix,  liver,  lung,  pleura,  and 
kidney. 

In  various  accounts,  particularly  the  earlier 
ones,  an  important  role  has  been  attributed 
to  carious  teeth  as  a  means  of  infection  of  the 
jaws.  One  observer  was  able  to  detect  the 
funj,'us  in  the  cavitj'  of  a  carious  tooth.  It  is 
hiilhly  improbable,  however,  that  infection  could 
take  place  through  the  apex  of  the  root  of  the 
tooth  unless  great  j)ressure  were  applied.  The 
presence  of  a  band  of  fibrous  tissue  leading  to 
the  carious  tooth  has  also  been  urged  as  support- 
ing the  view  that  the  infection  occurred  through 


Fio.  993. — Section  ol  a  liiuuaii  liver  sliuwmg  typical 
radial  arrangement,  from  which  the  name  acti- 
nomycosis (ray  fungus)  is  derived.  (From  a 
xpecunen  prepared  by  J.  Pollard.) 


the  tooth.  It  is  well  known  that  the  muco- 
periosteum  connected  with  a  carious  tooth  is 
usually  unhealthy,  from  the  toxic  products  of 
decomposition  that  occur  in  such  a  tooth  ;  these 
irritated  tissues  are  much  more  likely  to  become 
infected  in  cases  of  streptothrix  infection,  and 
although  the  consideration  for  the  present  can 
only  be  hypothetical,  the  latter  explanation 
would  certainly  seem  to  be  the  more  probable. 
Tlie  tissue  of  the  mouth  most  commonly 
affected  primarily  «ould  appear  to  be  the  bone 
via  a  carious  tooth,  from  the  various  text-book 
accounts  of  the  disease.  On  examining  the 
record  of  cases  this  certainly  does  not  seem  to  be 
so,  but  it  is  impossible  to  make  an  accurate 
statement  with  the  limited  amount  of  material 
at  present  available.  It  is  certain  that  parts 
25 


other  than  the  bone  are  infected  primarily,  one 
observer  stating  that  the  salivary  and  nuicous 
glands  are  quite  commonly  affected. 

Infection  of  any  part  of  the  mouth  may  take 
place ;  a  lesion  is  apparently  necessary  for  the 
entrance  of  the  fungus.  It  occurs  mo.st  fre- 
quently in  the  mandibular  region,  involving  the 
cheek,  gum,  mandible  itself,  tongue,  sulf-lingual 
and  sub-maxillary  glands,  and  other  parts,  most 
commonly  the  parotid  gland. 

The  fungus  may  enter  the  socket  from  wliich  a 
tooth  has  been  removed ;  it  is  suggested  that  it 
can  pass  along  the  ducts  of  the  salivary  and 
mucous  glands.  A  condition  of  chronic  irrita- 
tion certainly  seems  to  favour  the  growth  of  the 
fungus.  In  cases  of  so-called  pyorrhoea  alveo- 
laris  the  fungi  could  easUy  become  established. 
In  the  writer's  experience  an  infection  occurred 
in  the  case  of  an  imperfectly  erupted  third 
mandibular  molar. 

Xo  case  has  yet  been  described  in  the  earliest 
stage  of  infection.  Streptothrix  organisms  may 
be  found  in  the  mouth,  but  it  does  not  necessarily 
follow  that  they  are  pathogenic. 

A  painless  swelling  that  progresses  slowly  and 
may  be  consideraljly  indurated  is  present.  In 
due  course  softening  may  be  detected  with 
fluctuation,  but  only  over  an  area  quite  small 
in  comparison  with  the  size  of  the  swelling; 
more  than  one  of  these  areas  may  be  detected. 
At  the  same  time  puckering  of  the  skin  or 
nmcous  membrane  will  usually  be  noticed,  due 
to  the  formation  and  contraction  of  new  fibrous 
tissue.  The  skin  presents  a  peculiar  bluish 
appearance,  due  to  the  chronic  congestion  of 
the  part.  Attention  \\'\\\  usually  be  drawoi  to 
the  condition  earlier  when  a  secondary  infection 
exists  than  in  cases  of  simple  infection. 

If  an  incision  is  made  a  small  quantity  of 
discharge  exudes,  which,  unless  a  mixed  infec- 
tion is  present,  is  viscid  in  character  and  con- 
tains granules  that  are  typical  of  the  disease. 
These  granules  are  of  great  importance  from 
the  point  of  view  of  diagnosis ;  they  are  fre- 
quently yellowish  in  colour — "  sulphur  gran- 
ules ■' — and  of  a  spherical  or  rounded  shape. 
They  may  vary  in  colour  from  being  very  pale, 
yellow,  or  greyish  white,  to  brown ;  at  times 
t\\o  or  more  granules  may  cohere,  when  they  pre- 
sent an  irregular  outline.  Occasionally  granules 
are  not  seen,  but  on  examining  the  discharge 
microscopically  the  typical  branching  filaments 
should  be  found. 

If  the  bone  is  involved  the  periosteum  is 
usually  separated ;  a  large  surface  of  the  bone 
may  be  bared  in  this  way,  and  necrosis  may 
supervene,  but  docs  not  appear  to  be  common. 

In  cases  of  multiple  infection  the  amount  of 
pus  may  be  considerable,  and  may  mask  the 
presence  of  the  granules ;  in  such  cases  necrosis 
of  the  bone  maj'  be  marked. 


770 


The  mode  of  extension  of  the  infection  is 
characteristic ;  it  involves  any  tissue,  being 
less  limited  by  anatomical  boundaries  than  the 
majority  of  infective  processes. 

In  an  advanced  case  the  skin  is  puckered,  and 
may  present  scars  where  the  tissues  have 
healed,  whilst  sinuses  discharging  a  small  amount 
of  viscid  fluid  that  contains  granules  may  co- 
exist. A  neighbouring  part  may  show  small 
nodular  swellings  over  wliich  the  skin  is  closely 
adherent  and  of  a  bluish-red  colour.  The 
chronic  congestion  can  be  readily  demonstrated 
by  j)ressure,  the  colour  returning  very  slowly. 

The  absence  of  pain  is  a  noticeable  feature, 
and  may  account  for  the  frequent  delay  of  the 
patient  in  seeking  medical  assistance.  General 
infection  is  exceedingly  rare,  although  auto- 
inoculation,  from  the  mouth,  of  the  remaining 
part  of  the  alimentary  tract  must  be  kept  in 
mind.  Infections  of  the  viscera  are  very  serious 
and  usually  fatal ;  unless  this  occurs,  the 
prognosis  in  mouth  cases  where  the  disease  has 
been  recognized  and  proper  treatment  adopted 
is  quite  good. 

Cases  are  recorded  of  infection  extending 
dowiiwards  along  the  subcutaneous  tissue  of 
the  neck,  upwards  into  the  temporal  region,  or 
backwards  into  the  tissues  of  the  pharynx.  ! 
The  maxilla  seems  to  be  involved  only  rarely; 
cases  of  the  maxillary  sinus  being  infected  are  on 
record,  and  also  of  the  orbit. 

Cases  of  actinomycosis  rarely  present  any 
general  symptoms  where  the  infection  is  simple  ; 
the  temperature  is  not  affected,  nor  are  the  lymph 
glands  found  to  be  enlarged. 

Early  diagnosis  is  of  great  importance,  as  it 
enables  treatment  to  be  undertaken  while  the 
disease  is  limited,  since  at  this  stage  not  only  is 
unsightly  scarring  prevented,  but  also  the  risk 
of  general  dissemination  reduced  to  a  minimum. 

When  the  typical  appearances  described 
above  are  present,  granules  are  found  in  the 
discharge,  and  the  fungus  is  seen  under  the 
microscope,  the  diagnosis  is  certain.  It  is 
because  of  the  rarity  of  the  disease,  and  the 
difficulty  of  distinguishing  this  affection  in  the 
initial  stages  from  other  localized  chronic 
inflammatory  lesions,  that  an  early  diagnosis 
is  so  seldom  made.  If  a  chronic  inflammatory 
process  is  present  and  persists  in  spite  of  treat- 
ment, or  if  bare  bone  is  present  and  shows  little 
tendency  to  heal,  and  necrosis  does  not  become 
definitely  established,  the  discharge  should  be 
investigated  most  carefully  for  the  presence 
of  streptothrix. 

There  is  a  close  resemblance  between  this 
condition  and  a  tuberculous  infection.  The 
latter  is  very  rare  in  the  mouth,  and  nearly 
alwaj's  associated  with  pulmonary  tuberculosis  ; 
examination  of  the  discharge  will  be  of  the 
greatest  assistance,  but  an  examination  of  the 


chest  will  reveal  the  possibility  of  tuberculous 
disease.  A  case  of  this  nature  was  presented 
to  the  writer ;  a  tooth  socket  (mandibular 
molar)  did  not  heal  after  extraction  and  became 
chronically  inflamed ;  the  condition  persisted 
for  a  sufficient  length  of  time  to  become 
suspicious;  the  patient,  a  man  of  twenty-five 
years,  was  found  to  have  tubercle  bacilli  in  his 
sputum.  Another  case  in  which  a  strepto- 
thrix infection  was  suspected  was  due  to  a 
first  mandibular  molar  root,  which  had  been 
displaced  some  months  previously,  during  an 
attempt  at  extraction ;  a  sinus  was  present 
beneath  the  mandible,  with  marked  scarring. 
The  skin  was  puckered,  and  on  passing  a  probe 
bare  bone  could  be  felt ;  the  wound  in  the  mouth 
had  completely  healed ;  several  examinations 
of  the  discharge,  which  was  scanty,  were  made, 
but  with  negative  results.  The  root  was  dis- 
covered after  the  establishment  of  free  drainage. 
It  is  necessary,  as  in  all  chronic  inflammatory 
processes,  to  distinguish  the  condition  from 
malignant  disease — sarcoma  in  particular.  In 
carcinoma  ulceration  occurs  early  ;  in  actinomy- 
cosis it  is  rare.  The  lymph  glands  are  involved 
in  the  former,  but  not  in  the  latter.  Carcinoma 
in  the  mandibular  region,  apart  from  the  tongue, 
is  very  unusual,  and  the  area  of  malignant 
infiltration  does  not  show  the  presence  of  dis- 
charging sinuses.  Sarcoma  is  less  easy  to 
distinguish,  but  it  grows  pensistently,  docs  not 
tend  to  break  down,  and  is  more  closely  con- 
nected with  the  bone,  from  which  it  usually 
arises.  If  there  be  any  doubt  as  to  the  presence 
of  malignant  disease,  a  microscopical  section 
will  decide  the  character  of  the  swelling. 

Treatment. — Treatment  consists  in  removal, 
by  surgical  means,  of  the  area  infected,  either  by 
cutting  it  away  freely  or,  as  is  more  commonly 
done,  thoroughly  scraping  away  all  the  infected 
tissue,  the  part  being  loosely  packed  with  gauze 
and  irrigated  at  frequent  intervals  with  a  weak 
solution  of  iodine  in  water.  Great  care  must  be 
taken  to  avoid  a  secondary  infection. 

The  incision  should  be  made  externally  in 
order  to  avoid  the  risk  of  infecting  the  alimen- 
tary tract  beyond  the  mouth. 

Potassium  iodide  should  be  administered 
in  small  doses  at  the  commencement- — five  or 
ten  grains,  three  times  a  day — and  gradually 
increased ;  as  much  as  a  drachm  three  times  a 
day  has  been  given.  The  depressing  effect  of  the 
drug  is  considerably  reduced  if  strychnine  is 
administered  at  the  same  time.  The  potassium 
iodide  should  be  continued  for  at  least  six 
months. 

The  use  of  copper  sulphate  locally  has  been 
advocated  recently  in  these  cases. 

The  use  of  a  vaccine  has  proved  to  be  of 
value  in  a  few  recorded  cases. 

W.  W.  J. 


APPENDIX 


DENTAL   JURISPRUDENCE 


INTRODUCTION 

The  title  of  this  ApiJendix  requires  explana- 
tion, since  Dental  Jurisprudence  should,  strictly 
interpreted,  and  following  the  analogy  of  Medical 
Jurisprudence,  be  '"that  science  which  teaches 
the  application  of  every  branch  of  (dental) 
Knowledge  to  the  purposes  of  the  law  ",'  and 
should  be  equivalent  to  Forensic  Dentistry 
only.  The  clentist,  however,  is  not  called 
upon  so  frequently  as  his  medical  colleague  to 
assist  the  law  liy  the  employment  of  his  special 
skill  and  knowledge  in  those  classes  of  cases 
in  which  the  services  of  the  medical  man  are 
required  by  the  State  ;  nor  does  the  dentist  at 
the  present  time  have  to  render  to  any  great 
extent  services  analogous  to  those  of  medical 
officers  of  health, ^  nor  is  the  dentist  called  upon, 
to  any  great  extent,  to  give  evidence  as  an 
expert  witness  in  civil  cases  (accidents)  or  in 
criminal  (pathological  and  toxicologieal)  cases. 

The  history  of  Medical  Jurisprudence,  as  a 
special  science,  dates  perhaps  from  the  publica- 
tion in  1788  of  the  Elements  of  Medical  Juris- 
prudence, by  Dr.  Hamuel  Farr.^  There  is,  in 
England,  no  literature  of  Dental  Jurisprudence.'' 

This  appendix  must,  therefore,  be  taken  as  an 
outline  of  the  legal  relationships  into  which,  by 
virtue  of  his  professional  status,  the  dentist  is 
brought  (a)  with  the  State  (as  represented  by 
its  special  enactments  as  to  requirements  from 
his  profession),  (b)  the  lay  public,  and  (r)  his 
fellow  dental  practitioners. 

THE    DENTIST    AND    THE    STATE 

Legal  History 
In  the  early  history  of  English  law  there  is 
little  evidence  of  State  recognition  of  the  Dental 
profession.  The  history  of  the  Barbers  and 
Surgeons  in  England,  as  evidenced  by  the 
records  of  the  Trade  Guilds  and  Companies  of 
the  Middle  Ages,  and  references  to  these  in  muni- 

*  Taylor,  Medical  Jurisprudence. 

-  But  see  Education  (Administrative  Provisions)  Act. 
1907  (7  Edw.  VII.  c,  47)  and  Circular  of  Board  of  Edu- 
cation to  Local  Education  Authorities  of  April  !l.  1012, 
Paragraphs  4  &  8,  and  National  Insurance  Act.  litll. 
Fourth  Schedule,  Part  2  (I  &  2  Geo.  V,  c.  55). 

^  Guy,  Forensic  Medicine,  1861. 

*  The  Law  relating  to  Medical  Practitioners  and 
Dentists  in  Great  Britain,  by  J.  N.  Morton  (William 
Green  &  Sons,  London  &  Edinburgh.  1912),  contains 
(pp.  71--77)  a  chapter  on  the  Law  relating  to  Dentists. 


iTl 


cipal  and  other  records,  shows  that  dentistry, 
as  practised  by  surgeons  and  by  barbers,  was 
regulated  by  the  authorities  of  the  GuOds  and 
Companies,  as  a  branch  of  surgery  and  barbery. 
The.se  guilds  and  companies  enforced  a  certain 
amount  of  knowledge  on  their  members  and 
constituted  bodies  to  which  persons  damnified 
by  the  action  of  any  of  their  members  could 
apply  for  redress.  The  records  of  the  City  of 
London  show  that  the  Guild  of  Barber-Surgeons 
was  subject  to  regulations  as  to  practice  in  the 
fourteenth  and  fifteenth  centuries,'  e.  g.  in 
the  reign  of  Edward  II  there  is  a  record  that 
Richard  le  Barbour  was  appointed  to  have 
supervision  over  the  trade  of  the  barbers  (then 
surgeons  and  denti.sts),  and  had  power  in  the 
event  of  misbehaviour  to  "  distrain  "  upon 
them  and  to  cause  the  distress  to  be  taken  to  the 
Guildhall. 

In  the  year  1462  a  Charter  was  granted  to  the 
Barbers  Company  by  Edward  IV,  and  in  the 
preamble  occurs  perhaps  the  first  mention  of 
dentists  in  a  document  of  State.  The  Charter 
"  ordered  "  that  the  "  freemen  of  the  mystery 
of  Barbers  of  our  City  of  London  exercising  the 
mystery  or  art  of  surgery  .  .  .  and  dra\\ing  the 
teeth  of  our  liege  men  .  .  .  may  be  in  name  and 
deed  one  body  and  one  perpetual  commity,  etc."  "^ 

The  Guilds  exacted  certain  qualifications 
from  practitioners.  A  diploma  granted  in 
1497  by  the  Barbers  Companj'  to  a  freeman, 
enabling  him  to  practise  .surgery  after  examina- 
tion by  '■  experts  "  in  surgery,  contains  a 
reference  to  the  rights  of  the  Company  with 
regard  to  drawing  of  teeth.''  There  are  refer- 
ences to  dentistry  in  the  records  of  the  Barber- 
Surgeons  Companies  of  York  (a.d.  1522)  and 
of  Norwich.* 

In  the  year  1541  was  passed  the  Statute  32 
Hen.  VIII,  cap.  42,  where  is  found  the  first 
mention  of  dentists  in  a  statute  of  the  realm. 
It  enacted  {inter  alia)  that  barbers  were  no 
longer  to  practise  surgery  "except  drawing  of 
teeth  ".     The  Statute  Book  contains  no  further 

'  Riley's  Extracts  from  the  City  Records,  Letter-book, 
C.  fol.  96. 

'  As  quoted  by  Young,  Amuils  of  the  Barber- 
Surgeons,  1890,  p.  55.  The  Charter  is  preserved  at 
Barbers"  Hall. 

'  Young,  Annals  oj  the  Barber-Surgeons,  p.  69. 

'  P.  B.  Henderson,  "  Early  History  of  Dentistry  in 
England,"  Brit.  Dent.  Jour.,  pp.  49-56,  .Ian.   15,  1909. 


772 


enactments  relating  to  dentists  as  such  until 
the  passing  of  the  Dentists  Act  of  1878  (41  &  42 
Vict.,  cap.  33)  by  which,  supplemented  and 
partly  repealed  by  the  Medical  Act  of  1886 
(49  &  50  Vict.,  cap.  48),  and  by  the  Statute 
Law  Revision  Act  1894  (57  &  58  Vict.,  cap.  56), 
the  profession  is  now  regulated. 

The  Dentists  Act  contains  provision  for  the 
registration  of  dentists  and  (sec.  6)  provides 
that  any  one  \\  ho  is  a  licentiate  in  dental  surgery 
or  dentistry  of  any  of  the  medical  authorities, "^ 
or  is  entitled  to  be  registered  as  a  foreign  or 
colonial  dentist,^  or  was  at  the  passing  of 
the  Act  bona  fide  engaged  in  the  practice  of 
dentistry  or  dental  surgery,  either  separately 
or  in  conjunction  with  the  practice  of  medicine, 
surgery,  or  pharmacy,  may  be  registered  under 
the  Act. 

Sec.  5  discourages  the  practising  of  dentistry  ! 
by  unregistered  persons,  by  enacting  that  "  a 
person  sliall  not  be  entitled  to  recover  any  fee 
or  charge  in  any  court  for  the  performance  of 
any  dental  operation  or  for  any  dental  attend- 
ance or  advice  unless  he  is  registered  under  the 
Act  or  is  a  legally  qualified  medical  practitioner  ". 

Unregistered  Practice 

The  policy  of  the  law  is  not  such  as  to  forbid 
the  practice  of  dentistry  by  any  but  qualified 
and  registered  medical  men  and  qualified  and 
registered  dentists. 

In  this  it  follows  the  same  policy  as  in  regard 
to  other  professions,  but  not  all,  viz.,  no  one 
but  a  legally  qualified  solicitor  or  a  barrister 
may  engage  in  the  practice  of  the  law.  (Sed 
quaere  whether  the  Statute  3  Hen.  VIII,  cap. 
11,  sees.  1  and  2,  is  not  still  in  force — being 
unrepealed — ^^hich  forbids  altogether  the  prac- 
tice of  medicine  and  surgery  bj'  iniqualified 
persons.)  ^ 

The  Medical  Act.  1858,^  by  sec.  40,  also 
imposes  a  penalty  in  the  case  of  any  one  wilfully 
or  falsely  pretending  to  be  a  physician  or 
surgeon  or  to  be  registered  under  the  Act ;  the 
um-egistered  medical  practitioner  is  also  ^  pro- 
hibited from  suing  for  his  fees. 

1  By  sec.  19  of  the  Dentists  Act  of  1878  tliese  are  : 
Royal  College  of  Surgeons  of  England,  Royal  College 
of  Surgeons  of  Edinburgh,  Faculty  of  Physicians  and 
Siu'geons  of  Glasgow,  Royal  College  of  Surgeons  in 
Ireland,  and  any  University  in  the  United  Kingdom. 

^  Under  sees.  8,  9,  and  10  of  the  Dentists  Act  a 
foreign  or  colonial  dentist  is  one  who  holds  a  certificate, 
etc.,  granted  in  a  British  possession  or  in  a  foreign 
country  which  certificate  is  recognized  by  the  General 
Medical  Council  as  entitling  the  holder  to  practise 
dentistry  or  dental  surgery  in  such  British  possession 
or  foreign  country  and  as  furnishing  sufficient  guaran- 
tees of  the  requisite  knowledge  and  skill  for  the  efficient 
practice  of  dentistry  or  dental  surgery. 

■'•  See  Davies  v.  Makuna,  29  Ch.  D.  596. 

'   21  &  22  V'ict.,  cap.  90. 

5   Ibid.,  sec.  32.  i 


The  unregistered  dentist  has,  as  above 
mentioned,  no  ground  of  action  for  his  fees  by 
sec.  5  of  the  Dentists  Act.**  The  Medical  Act, 
1886,'''  sec.  6,  is  permissive  and  enables  a 
registered  medical  practitioner  to  recover  his 
charges  for  "  medicaments  and  other  appliances  ". 

Tlie  Medical  Act,  1858,  however,  also  prohibits 
the  unregistered  person  from  recovering  fees 
"  for  any  medicine  which  he  shall  have  both 
prescribed  and  supplied".' 

The  Dentists  Act,  lio\\ever,  does  not  prohibit 
the  unregistered  practitioner  from  instituting 
a  suit  for  the  price  of  mechanical  work  done  by 
him,  such  as  the  making  of  artificial  dentures, 
a  branch  of  the  dental  profession  that  has 
no  precise  analogue  in  the  medical  and  surgical 
professions.  For  the  disi^ensing  of  medicines 
has  perhaps  points  of  difference  from  a  mechani- 
cal art,  and  the  surgeon  does  not  manufacture 
the  surgical  appliances  the  use  of  which  he 
directs.  In  the  case  of  Herman  v.  Duckworth,'^ 
it  was  decided  that  an  unregistered  dental 
practitioner  (in  this  case  a  company  limited 
by  shares)  can  recover  the  price  of  a  set  of 
artificial  teeth  supplied,  the  claim  being  good  in 
so  far  as  it  was  for  the  making  of  the  set  of  teeth 
as  distinguished  from  the  fitting,  and  from  the 
filling  of  carious  teeth.  "  Fitting  and  filling  " 
are  "  dental  operations  '"  within  the  meaning 
of  the  words  in  sec.  5  of  the  Dentists  Act.  Lord 
Cliief  Justice  Alverstone  stated  that  the  claim 
was  valid  as  for  "goods  supplied,  not  fitting 
or  filling  ".  Mr.  Justice  Wills  concurred  in  the 
judgement,  but  with  reluctance,  having  regard, 
as  he  said,  "  to  the  care  and  skill  required  in 
the  preparation  of  false  teeth  ",  which,  were 
it  not  for  the  strict  construction  required  (as 
always)  to  be  placed  upon  the  words  of  a 
Statute  (in  this  case  the  words  "  dental  opera- 
tion "),  might  have  led  in  his  mind  to  the  failure 
of  the  claim.  But  " '  dental  operation  '  must 
mean  an  operation  in  a  surgical  sense  upon  a 
living  patient,  and  not  makmg  false  teeth".'*' 
In  Seymour  v.  Pickett  ^^  the  Court  of  Appeal 
held  that  an  unregistered  dental  practitioner 
may  maintain  an  action  for  the  price  of  material, 
such  as  gold  supplied,  and  false  teeth,  and  for 
goods  supplied  and  work  done  outside  the 
words  of  sec.  5  of  the  Act.'- 

^  41  &  42  Vict.,  cap.  33. 

'   49  &  50  Vict.,  cap.  48. 

«  21  &  22  Vict.,  cap.  90,  sec.  32,  cit.  sup. 

'  20  Times  Law  Reports,  436. 

1"  Wills,  J.,  loc.  cit.  sup. 

^  (1905)  1  K.B.  715. 

"  See  Lee  v.  Griffin,  30  L.J.Q.B.,  p.  252.  A  contract 
to  make  a  set  of  artificial  teeth  is  a  contract  for  sale  of 
a  chattel  and  within  sec.  17  of  the  Statute  of  Frauds 
(29  Car.  II,  cap.  3),  and  an  action  for  work  labour  and 
materials  cannot  bo  maintained  (outside  the  Statute) 
against  the  executor  of  a  patient  dying  before  teeth  are 
fitted  and  delivered;  and  see  Sale  of  Goods  Act  1893, 
sec.  4  (56  &  57  Vict.,  cap.  71). 


773 


The  State  \\ill  not,  however,  permit  the 
unregistered  dental  practitioner  to  hold  liimself 
out  to  the  public  as  being  a  "dentist  ",  following 
in  this  respect  the  analogy  of  sec.  40  of  the 
Medical  Act  of  1858;  i  for  sec.  3  of  the  Dentists 
Act  of  1878  provides  that  "a  person  shall  not 
be  entitled  to  take  or  use  the  name  or  title 
of  '  dentist '  (either  alone  or  in  combination 
\\ith  any  other  \\ord  or  words),  or  of  '  dental 
practitioner  ',  or  any  name  title,  addition,  or 
description  implying  that  he  is  registered  under 
this  Act  or  that  he  is  a  person  specially  quali- 
fied to  practise  dentistry  unless  he  is  registered 
under  this  Act  ",  under  a  penalty  not  exceeding 
£20  ;  and  sec.  26  of  the  Medical  Act,  1 886,2  enacts 
that  "  the  words,  '  title,  addition,  or  description,' 
where  iised  in  the  Dentists  Act,  1878,  include 
anj'  title  or  addition  to  a  name,  designation,  or 
description  whether  expressed  in  words  or  by 
letters  or  partly  in  one  way  and  partly  in  the 
other  ". 

Sec.  4  (2)  of  the  Dentists  Act,  1878,  also 
provides  that,  "  If  a  jjerson  takes  or  uses  the 
designation  of  any  qualification  or  certificate 
which  he  does  not  possess  "  he  shall  be  liable 
to  a  penalty. 

There  have  been  numerous  prosecutions^ 
under  the  Act,  wliicli  are  generally  instituted 
bj^  the  societies  and  associations  formed  for  the 
general  regulation  of  the  dental  profession  as  a 
whole,  and  by  societies  specially  formed  or 
incorporated  for  the  more  limited  purpose  of 
the  protection  of  their  members  against  the 
invasion  of  their  legal  rights  in  this  and  other 
respects  by  members  of  the  general  public.  1 
The  Medical  Act,*  1886,  sec.  26,  however, 
enables  such  prosecutions  to  be  instituted  by 
a  private  person. 

The  meaning  of  the  words  "  specially  quali- 
fied "  in  sec.  3  of  the  Dentists  Act,  1878,  has 
formed   the    subject   of   several   decisions.     In 

'  Cit.  sup. 

2  49  &  50  Vict.,  cap.  48. 

^  See  reports  in  the  British  Dental  Journal  passim, 
sub  titulo  "  Legal  Intelligence". 

There  have  been  convictions  for  use  of  the  letters 
D.D.S.  after  a  proper  name  as  implj-ing  registration 
under  the  Dentists  Act,  e.  g.  British  Dental  Association 
V.  Drew,  1906  (Plymouth);  and  for  unlawful  use  of 
the  words  '"  Siu'geon-Dentist  "  by  persons  not  regis- 
tered. British  Dental  Association  v.  Smith,  1907 
(Chatham).  B.D.A.  v.  Wickman.  Conviction  for 
use  of  words  "  Registered  Siu-geon  Dentist,  B(risbane), 
Q(ueensland),  A(ustralia)  ",  April,  1908.  Prosecutions 
must  be  instituted  before  two  justices  or  a  stipendiary 
under  the  provisions  of  the  Summary  Jurisdiction 
Acts.  Et  vide  Robertson  v.  Hawkins  (1912),  29  T.L.K. 
33  (1913),  1  K.B.  57,  82  L.J.K.B.  97:  Held,  that  the 
statement  by  an  unregistered  dentist  that  he  had  granted 
certificates  (required  to  be  granted  by  a  registered 
dentist)  and  that  he  would  grant  such  a  certificate  fell 
within  sec.  3  of  the  Act  as  using  the  name  of  registered 
dentist  and  as  implying  that  he  was  registered. 

•  49  &  50  Vict.,  cap.  48. 


Barnes  v.  Brown,^  it  was  held  that  the  making 
of  statements  laudatory  or  commendatory  of 
the  dental  work  done  by  the  person  making 
them  (not  a  registered  dentist),  was  a  holding 
out  to  the  public  of  that  person  as  one  "  specially 
qualified  to  practise  dentistry  "  under  sec.  3  of 
the  Act,  and  so  rendered  that  person  amenable 
to  a  penalty.  The  words  in  that  case  held  to 
imply  special  "  qualification  "  were  "  Finest 
artificial  teeth  at  moderate  prices.  .  .  .  English 
and  American  teeth.  Painless  extractions". 
But  the  reasoning  followed  in  this  case  did  not 
long  stand.  In  the  case  of  Bdlerhy  v.  Heyworth 
and  others,'^  which  came  before  the  Court  of 
Appeal  on  appeal  from  the  decision  of  Parker, 
J.,  following  Barnes  v.  Brown,  and  being  a  case 
in  which  a  dentist  partner  claimed  to  dissolve 
partnership  for  breach  of  a  clause  in  the  partner- 
ship articles  providing  for  dissolution  in  the 
event  of  either  partner  contravening  the 
provisions  of  the  Dentists  Act,  it  was  held  by 
the  Court  of  Appeal  that  the  use  of  the  words 
"  Finest  Artificial  teeth.  Painless  extractions. 
Advice  free.  Mr.  H.  attends  here  ",  did  not 
amount  to  a  holding  out  as  being  "  specially 
qualified  "  to  jDractise  dentistry  within  the 
meaning  of  sec.  3  of  the  Dentists  Act.  The 
Master  of  the  Rolls  ' expressed  himself  "unable 
to  follow  the  reasoning  in  that  case  [t.e  Barnes 
V.  Brow7i],  which  seems  to  me  to  go  the  length 
of  sajang  that  people  must  not  announce  that 
they  do  that  which  by  law  they  are  entitled  to 
do  (».  e.  practise  dentistry),  and  that  by  saying 
that  they  do,  and  do  well,  that  which  the  law- 
entitles  them  to  do,  they  are  necessarily  infring- 
ing the  Act  "  ;  and  on  page  28  of  his  judgement — 
"  as  I  read  that  section  [sec.  3]  it  is  directed  to 
the  personal  description  of  the  man  as  dis- 
tinguished from  the  description  of  the  work 
which  the  man  does." 

The  judgement  of  Buckley,  L.J..  in  the  same 
case,  contains  a  further  elucidation  of  the 
interpretation  to  be  placed  upon  the  intention 
of  the  Statute  and  upon  the  true  meaning  of 
the  words  "  .specially  qualified  ".  He  says 
that  under  the  Act.  "  any  man  may  say  that 
he  does  dental  acts,  but  he  mu.st  not,  unless 
he  is  a  qualified  person,  say  that  he  does  them 
as  a  dentist."  He  must  not  "  describe  himself 
as  being  a  person  of  a  particular  kind,  but  he 
is  entitled  to  say  that  he  is  there  to  do  a  parti- 
cular class  of  acts ".  In  brief,  the  words 
"  specially  qualified  "  in  sec.  3,  are  to  be  taken 
to  mean  "  specially  qualified  "  by  diploma,  certi- 
ficate, or  degree,  and  not  to  apply  to  puffing 
advertisement  of  special  "  competency  ".  They 
are    intended   to    refer   to    description    of   the 

5  (1909)  L.K.,  1  K.B.  38. 

«  (1909)  2  Ch.  (C.A.);    H.L.    (E.)   App.   Cas.    (1910), 
377. 
'  Cozens-Hardy,  M.R. 


774 


person  and  not  to  description  of  the  acts  of 
that  person.  "  It  is  difficult  to  ckaw  the  line 
and  say  -where  a  description  by  reference  to 
acts  ends,  and  a  description  of  the  person 
begins."  ^ 

The  case  of  Panhans  v.  Brown,^  where  the 
use  of  the  words  "  West  Central  Dental  Insti- 
tute "  by  an  unregistered  person  was  held  to 
be  an  infringement  of  sec.  3,  was  distinguished, 
on  the  ground  that  there  the  uiu'egistered 
practitioner  "  said  he  ^^'as  a  dentist,  called 
himself  a  dentist  ",  under  this  synonym. 

BeUerby  v.  Heyworth  was  taken  to  the  House 
of  Lords  on  appeal. 

In  the  meantime  the  case  of  Byrne  v.  Rogers  ^ 
had  been  decided  in  Ireland,  ^^here  the  ^^•ords 
u.sed  {inter  alia)  and  complained  of  as  implying 
'"special  qualification"  were  "consult  Mr.  B. 
the  \^-orkrs  expert  adapter  of  teeth  ;  he  tenders 
you  original  advice  on  the  treatment  acquired 
through  his  vast  experience  of  twenty-five 
years  abroad ;  decayed  teeth  infallibly  treated 
by  nature's  own  remedy",  etc.  "Extractions 
by  my  own  great  secret  method  mthout  gas, 
cocaine,  or  other  drugs",  etc.  "Extractions 
by  my  own  special  system.  Painless  and  blood- 
less ",  etc. 

The  judgements  in  that  case  approved 
BeUerby  v.  Heyworth,  and  dissented  from  the 
reasoning  in  Barnes  v.  Brown,  and  the  inter- 
pretation placed  upon  the  words  "  specially 
(jualified  "  was  that  they  meant  "  qualified  by 
diploma,  licence,  degree,  or  hall-mark,  and  do 
not  include  persons  qualified  by  mere  personal 
skill,  practice,  or  training  ".*  In  Barnes  v. 
Brown,  it  had  been  held  that  "  specially 
qualified  "  meant  "  specially  qualified  by  ac- 
complishments— by  personal  skill  as  distin- 
guished from  qualification  out.side  the  person, 
such  as  by  diploma,  degree,  or  other  hall-mark  ",'^ 
but  this  latter  view  could  not  be  maintained. 

In  Byrne  v.  Rogers  it  was  not  contended  that 
the  advertisements  claimed  to  have  any 
"  qualification  "  dependent  on  diploma,  degree, 
or  hall-mark,  or  any  of  the  qualifications 
referred  to  in  sec.  6  of  the  Dentists  Act,  but  it 
was  argued  that  there  was  a  claim  to  "  special 
qualification  "  by  reason  of  study,  practice, 
and  training,  and  that  that  ^vas  enough  to 
make  (the  defendant)  amenable  to  the  section 
(3).  But  the  clear  meaning  of  "  qualification  " 
in  the  Act,  as  derived  from  the  preamble  to 
the  Act  (now  repealed,  but  readable  as  showing 
the  intention  of  the  legislature)  and  from  sec.  4 
(1)  and  (2),  sec.  7  and  sec.  11,  is  qualification 

•  Per  Buckley,  L..J.,  loc.  cil. 
»  68,  J.P.  435. 

»  2Ir.  Rep.  1910,  K.B.D. 

*  Per  Lord  O'Brien  (L.C.J.)  in  Judgement,  pp.  225 
et  aeq. 

'  Per  Lord  O'Brien,  lor.  cit. 


in  a  technical  sense — qualification  by  degree 
or  diploma — and  the  word  must  not  be  taken 
as  merely  equivalent  to  "  competency ",  or 
taken  in  a  popular  sense.  And,  therefore, 
it  follows  and  is  now  (by  the  decision  on  the 
hearing  of  the  appeal  in  BeUerby  v.  Heyworth 
in  the  House  of  Lords,  a23pro\dng  the  decision 
of  the  Court  of  Appeal  in  BeUerby  v.  Heyworth, 
and  aj)j)roving  Byrne  v.  Rogers)  settled  law, 
that  an  advertisement  implying  that  the 
advertiser  is  specially  competent,  but  not  that 
the  advertiser  has  a  qualification  derived  from 
some  medical  or  dental  authority,  and  not 
implying  that  he  is  registered  uncler  the  Act, 
and  not  using  the  words  ''  dentist  "  or  "  dental 
practitioner  ",  does  7iot  render  the  advertiser 
subject  to  the  penalty  imposed  bv  sec.  3  of 
the  Act. 

Further,  there  is  the  right  in  the  advertiser 
to  notify  to  the  public  that  he  carries  on  dental 
work  (provided  he  does  not  use  the  word 
"  dentist  "  or  "  dental  practitioner  ",  by  which 
he  would  imply  registration  under  the  Act) ; 
for  "  the  Act  of  1878  never  took  away  the  right 
in  any  one  to  do  dental  work  in  all  its  branches  ".* 

There  can  be  no  reasonable  doubt  that  this 
is  the  true  meaning  and  intention  of  the 
section ;  for  otherwise  "  self-commendation 
would  be  prohibited  except  to  registered 
persons",  and  the  unregistered  man  "must 
not  imply  himself  to  be  a  comj)etent  or  skilful 
person  ",  which  is  "  not  a  very  likely  thing 
for  Parliament  to  have  enacted  "  ;''  and,  again,  it 
cannot  be  supposed  that  the  "  law  forbids 
persons  to  announce  that  they  do  that  which 
by  law  they  are  entitled  to  do  ".^ 

It  may  be  noted  here  that  in  the  case  of 
Elmslie  v.  Paterson '  the  A^ords  complained  of 
Mere   "  American  Dentistry  "    on   a   door-plate 

*  Byrne  v.  Rogers,  cit.  sup. ;    'per  Wright,  J. 

'  BeUerby  v.  Heyworth,  H.L.  (E.);  (1910).  App. 
Cas.,  377,  per  Loreburn  (L.C.) 

*  BeUerby  v.  Heyivorth,  C.A.,  per  Cozens-Hardy, 
M.R.,  loc.  sup.  cit.  Et  vide  Minter  v.  Snow,  74  J.P. 
258,  54  Sol.  Jo.  441,  (H.L.)  where  use  of  the  words 
"English  and  American  Dentistry"  and  "Dental 
Institute  "  were  held  not  witliin  sec.  3. 

»  24  Rep.  Court  of  Session  Cases  (1896-7),  (Justiciary 
Cases),  p.  77,  and  see  Bremridge  v.  Hume.  23  R. 
Justiciary  Cases,  p.  9,  2  Adam  24. 

Note  also  Boyal  College  of  Veterinary  Surgeons  v. 
Robinson  (1892),  1  K.B.,'557.  (Sec.  17  of  Veterinary 
Surgeons  Act,  1881,  44  &  45  'Vict.,  cap.  62).  Held,  that 
description  of  preinises  as  "  Veterinary  Forge 
implied  "  special  qualification  "  to  practise  veterinary 
surgery.  Royal  College  of  Veterinary  Surgeons  v. 
Collinson  (1908),  2  K.B.,  248,  "  canine  speciahst  "  was 
an  implication  of  "  special  qualification  "  to  practise 
veterinary  surgery. 

Pharmaceutical  Society  v.  Mercer  (1910),  1  K.B., 
p.  74.  Held  that  the  words  "  The  Pharmacy  "  over  a 
door,  following  the  name  of  a  person,  were  not  sufficient 
to  be  taken  to  imply  that  he  was  registered  under  the 
Pharmacy  Act,  1852  (15  &  16  Vict.,  cap.  56,  sec.  12), 
or  was  a  member  of  the  Pharmaceutical  Society. 


775 


followed  by  tlie  name  of  the  unregistered 
practitioner,  and  on  another  plate  "  Dental 
Office  ".  In  this  case  it  was  decided  that  no 
offence  had  been  committed  under  the  Act, 
and  tliat  these  inscriptions  did  not  imply 
"  special  qualification  ".  Lord  Moncrcift"  in  his 
judgement  remarks  that  the  words  "  do  no 
more  than  notify  that  Dentistry  is  carried  on 
within.  They  are  equivalent  to  '  Teeth  drawn 
here  '  ".  The  reasoning  of  this  judgement  seems 
irrefutable,  and  the  meaning  of  "  special  quali- 
fication "  appears  now  to  have  been  settled 
beyond  cavil. 

Limited  Companie.s 

The  provisions  of  the  Companies  Acts  (now 
consolidated  by  the  Companies  (Consolidation) 
Act,  1908  [8  Edw.  VII.  cap.  69.],  as  amended 
by  the  Companie?  Act,  1913  [3  and  4  Geo. 
V.  cap.  25])  as  to  limited  liability  companies, 
enabled  persons  desirous  of  carrying  on  dental 
work  for  profit  to  form  a  limited  liability 
company  for  that  purpose,  sometimes,  no 
doubt,  with  the  intention  of  carrying  on  for 
profit  a  genuine  business  to  be  carried  on 
hy  qualified  persons,  at  other  times  for  the 
purpose  of  evading,  by  means  of  ''  one-man  " 
companies,  the  penalties  under  the  Dentists 
Act,  which  ^\•ould  have  attached  to  an  individual 
unregistered  person  carrying  on  business,  and 
holding  hiniiself  out  as  registered. 

Tlie  first  question  to  be  decided  by  the  Courts 
(seeing  that  the  Dentists  Act,  1878,  had  been 
passed  at  a  time  when  such  "one  man"  com- 
panies had  not  been  incorporated)  ^^■as  whether 
the  word  "  person  "  in  the  penal  clauses  of  the 
Dentists  Act  could  be  construed  as  including 
"  corporation  ''  and  so  render  those  companies 
amenable  to  penalties,  or  whether  the  word 
must  be  treated  as  referring  merely  to  a  natural 
person  or  individual.  Prima  facie,  it  would 
have  appeared  that  the  word  "  person  "  should 
include  a  corporation,  if  necessary  to  the 
proper  carrying  out  of  the  policy  of  the  Act ; 
otherwise,  not. 

A  similar  question  had  occurred  in  the  case 
of  Pharmaceutical  Society  v.  London  and 
Provincial  Supply  Association,^  where  it  had 
been  held,  that  where  a  small  body  of  persons, 
one  of  whom  was  a  qualified,  certified,  and 
registered  chemist,  had  formed  tliemselves  into 
a  company  registered  with  limited  liability, 
the  company  could  not  be  convicted  under 
31  &  32  Vict.,  cap.  121,  sees.  1  and  15,  since  the 
word  "  person "  in  these  sections  did  not 
apply  to  a  corporation,  though  the  actual 
seller  of  poisons  in  the  company's  premise-s 
must  be  (as  in  this  case  it  was),  a  qualified 
person. 

'   (1880)  5.  App.  Cas.  857. 


The  question  first  arose  in  connection  with 
the  provisions  of  the  Dentists  Act  in  the  case 
of  O'Duffy  V.  Jaffe,'  where  a  company  had  been 
incorporated  under  the  title  ""  Jaffe,  Surgeon- 
Dentists,  Ltd."  ;  and  it  was  held  that  the  word, 
'"  person  "  in  the  Dentists  Act  relates  only  to 
individuals  and  not  to  a  company.  "  The  Act 
only  punishes  individuals."  ^  The  decision,  how- 
ever, only  went  so  far  as  to  rule  that,  once 
a  company  had  been  incorporated,  it  could 
not  be  made  liable  to  the  penalties  under  the 
Dentists  Act ;  but  it  appeared  that  the  Court 
was  of  opinion  that  "  the  formation  of  a  company 
of  this  nature  was  intended  to  be,  and  was,  an 
evasion  of  the  Act  ".* 

This  case  was  followed  by  that  of  Rex  (Rowell) 
V.  Registrar  of  Joint  Stock  Companies  for 
Ireland,'^  where  a  company  was  sought  to  be 
registered  under  the  title  "  S.  G.  Rowell, 
Dentist,  Ltd.". 

A  mandamus  was  applied  for  to  compel  the 
Registrar  of  Joint  Stock  Companies  in  Ireland 
to  register  the  company  with  that  name, 
but  the  Court  refused  to  grant  the  mandamus, 
on  the  ground  that  the  use  by  the  company  of 
the  proposed  name  would  involve  a  false  repre- 
sentation tending  to  mi.slead  the  public ;  the 
false  representation  being  either  that  "  S.  G. 
Rowell  "  was  a  "  dentist  ",  i.  e.  a  person 
registered  under  the  Act,  which  he  was  not,  or 
that  the  company  was  a  "dentist  ",  registered 
under  the  Act,  which  it  was  not.  A  company, 
therefore,  containing  the  word  "  dentist  "  as 
part  of  its  name  cannot  now  be  registered. 

But  the  Courts  have  gone  further  in  protect- 
ing the  j)ublic  against  companies  representing 
themselves  as  carrying  on  the  business  of 
"  dentists  '",  /.  e.  of  persons  registered  under 
the  Act. 

The  case  of  the  Attorney-General  v.  Appleton  '• 
was  that  of  a  company  formed  under  the  name 
of  "  Mr.  Appleton.  Surgeon  Dentist,  Ltd.", 
"  to  carry  on  through  competent  persons  the 
business  of  dentists  or  dental  surgeons  .  .  . 
and  to  employ  suitable  persons,"  etc.  None 
of  the  directors  or  other  persons  forming  the 
company  was  a  qualified  dentist  registered 
under  the  Dentists  Act.  In  an  information 
by  the  Attorney-General  it  was  alleged  that 
the  company  was  formed  for  the  fraudulent 
purpose  of  deceiving  the  public  by  falsely 
representing  that  the  business  was  carried  on 
by  persons  registered  under  the  Dentists  Act. 
The  defendants  did  not  put  in  any  defence, 
and  it  was  held  that  the  Attorney-General, 
suing   in  the    public    interest    to    prevent    an 


"  (1904),  2  Ir.  Rep.,  27. 

^  Per  Gibson,  J.,  loc.  cit.  sup. 

»  Kt  vide  Brown  V.  Whilloek,  10  T.L.R. 

5  (1904)  2  Ir.  Rep.,  (534. 

«  (1907)  1  Ir.  Rep.  252. 


524. 


776 


admitted  fraudulent  attempt  to  evade  statutory  I 
provisions,  was  entitled  to  an  injunction  to 
restrain  the  carrying  on  of  the  business.  The 
case  of  the  Attorney-General  v.  Myddleton's,  Ltd.^ 
went  further.  In  that  case  the  company  was 
registered  as  "  Myddleton's,  Limited  ",  the  title 
thus  containing  neither  the  word  "  dentist  "' 
nor  any  allusion  to  dentistry.  The  purpose  of 
incorporation  was  to  carry  out  dental  operations 
by  means  of  properly  qualified  persons,  a 
purpose  which  was  "not  per  se  illegal".^ 
There  was  no  evidence  that  unqualified  persons 
had  carried  on  dental  operations  for  the 
company.  But  there  was  evidence  that  in 
the  official  returns  of  the  company,  e.  g.  the 
return  of  allotments,  and  the  register  of 
directors  and  managers,  unregistered  persons 
had  been  described  as  dentists,  as  also  in 
advertisements  issued  by  tlie  company ;  an 
injunction  was,  therefore,  granted,  restraining 
the  company  from  continuing  to  employ  an 
unregistered  person  under  the  title  of  "  dentist  " 
to  carry  on  business  for  it,  and  from  holding 
forth  in  the  official  returns  or  in  advertisements 
or  elsewhere  or  otherwise  that  such  umegistered 
person  was  a  "dentist  ",  or  that  the  comijany 
comprised  or  employed  persons  of  the  name  of 
Myddleton  who  were  "dentists". 

In  Attorney-General  v.  G.  C.  Smith,  Ltd.,^  it 
was  *  held  that  the  Court  will  restrain  a  comi^any 
from  representing  that  they  carry  on  the 
business  of  dentists  in  succession  to  a  man 
struck  off  the  register  of  dentists,  or  that  they 
are  dentists  or  dental  practitioners,  or  from 
taking  a  name  implying  that  they  are  registered 
under  tlie  Dentists  Act,  or  are  specially 
qualified  to  practise  dentistry. ^ 

The  law,  therefore,  will  prevent  both  in- 
dividuals and  corjjorations  from  representing 
to  the  public  that  they  are  dentists,  or  dental 
practitioners,  or  are  specially  qualified  to  practise 
dentistry  witliin  the  meaning  of  the  Act,  i.  e. 

1   (1907)  1  Ir.  Rep.  471. 

^  Barton,  J.,  loc.  cit.  p.  477. 

^  (1909)  2Ch.  524. 

*  Vide  Attorney-General  v.  Shrewsbury  {Kingsland) 
Bridge  Co.  (1882)  21  Ch.  D.  752,  where  it  was  hold  that 
an  injunction  would  lie  to  restrain  a  company  com- 
bining to  carry  on  business  of  veterinary  surgeons 
without  employing  qualified  persons,  as  being  a  fraud 
on  the  public  ;  et  vide  La  Societe  Anonyme  des  Anciens 
6tablissernents  Panhard  et  Leimssor  v.  Panhard  et 
Levassor  Motor  Co.  (1901),  2  Ch.  513.  Attorney- 
General  v.  Ashbourne  Reereation  Ground  Co.  (1903), 
1  Ch.  101.  Devonport  Corporation  v.  Tozer  (1903), 
1  Ch.  759.  Attorney. General  v.  Wimbledon  House 
Estate  Co.  (1904),  2  Ch.  34.  Attorney-General  v. 
Tiirmingham  etc.  Drainage  Board  (1910)  1  Ch.  48. 

'  Et  vide  Attorney-General  v.  Churchiirs  Veterinary 
Sanatoritim  Limited  {IQIO),  2  Ch.  401.  Held,  injunction 
will  lie  to  restrain  Company  from  falsely  representing 
that  the  individuals  who  comprise  it  or  are  employed 
by  it  are  Veterinary  surgeons  (approving  and  following 
Attorney-General  v.  Myddletons,  cit.  sup.). 


are  registered  under  the  Act,  the  intention  of 
the  Act  being  to  distinguish  sharply  between 
the  class  of  registered  and  uni'cgistered  practi- 
tioners, and  then  to  leave  the  public  to  choose 
which  they  will  employ. 

The  British  Dental  Association,  in  view  of 
the  state  of  tlie  law  as  laid  down  in  the  fore- 
going decisions,  and  in  other  directions,  and 
with  a  view  to  better  provision  for  the  pro- 
tection of  the  public  from  the  effects  of  practice 
by  unregistered  persons,  are  considering  the 
desirability   of   promoting   legislation. 

Expert  Evidence 

The  dental  practitioner  may  be  called  upon 
to  give  evidence  in  a  Court  of  Justice  in  two 
capacities — 

(1)  As  an  ordinary  witness  as  to  fact;  and 
in  this  case  the  same  princijJes  of  evidence 
apply  as  in  the  case  of  any  other  lay  member 
of  the  public,  and  his  professional  status  is  not 
relevant. 

(2)  As  an  expert  witness ;  in  this  latter  case 
he  may  be  called  upon  to  give  evidence  as  to 
his  opinion  on  facts  observed  by  himself,  or  as 
to  his  opinion  on  facts  observed  by  and  stated 
by  others,  from  \\hich  he  is  asked  to  draw 
inferences.  The  admission  of  expert  evidence 
is  only  permissible  on  scientific  subjects.  "  A 
witness  may  not,  on  other  than  scientific  sub- 
jects, be  asked  to  state  his  opinion  on  a  question 
of  fact,  which  is  for  the  jury  ".*  "  Tlie  opinion 
of  witnesses  possessing  peculiar  skill  is  ad- 
missible whenever  the  subject  matter  of  inquiry 
is  such  that  inexperienced  persons  are  unlikely 
to  prove  capable  of  forming  a  correct  judgement 
upon  it  without  such  assistance ;  in  other 
words,  when  it  so  far  partakes  of  the  nature  of 
a  science  as  to  require  a  previous  habit  or  study 
in  order  to  the  attainment  of  a  knowledge  of 
it."" 

In  cases,  therefore,  where  the  question  at 
issue  involves  a  knowledge  of  dental  subjects 
not  possessed  by  the  ordinary  layman,  the 
practitioner  may  be  called  on  for  his  opinion  on 
the  facts ;  but  it  must  be  carefully  observed, 
that,  though  an  opinion  can  be  given  from  the 
proved  facts,  e.  g.  that,  given  certain  proved 
facts,  was  the  treatment  employed  by  the 
practitioner  whose  conduct  is  in  question  in  the 
case  correct ;  yet,  if  the  analogy  of  the  proper 
procedure  in  medical  cases  be  followed,  the 
opinion  of  one  practitioner  as  to  whether  a  fellow- 
practitioner  has  properly  discharged  his  duty 
to  his  fellow  practitioners  cannot  be  admitted 
as  expert  evidence — "  the  opinion  of  experts  as 
to  whether  a  [physician]  has  honourably  and 

'  Taylor  on  Evidence,  pars.  1419-20. 

'   1  Smith's  Leading  Cases  :  Notes  to  Carter  v.  Boehm. 


faitht'ully  discharged  his  duty  to  liis  |inc(lii-al| 
brethren  cannot  be  admitted.  " ' 

The  expert  witness,  in  addition  to  the  per- 
mission to  give  his  opinion,  and  not  state  only 
what  happened,  may  also  (1)  detail  experi- 
ments he  made  even  beliind  the  back  of  the 
otlier  party,  (2)  can  cite  books  of  admitted 
authority,  (3)  can  cite  other  cases  and  reports 
of  other  transactions  throwing  light  on  the  fact 
in  issue. ^  The  exjiert  witness  should  give  his 
opinion  on  the  facts  as  proved  and  should  not 
dispute  facts.^  Notes  may  be  used  in  court  to 
refresh  the  memory,  provided  tliey  are  notes 
taken  at  the  time  the  occurrences  happened, 
and  not  notes  written  down  some  time  after- 
wards. 

As  an  ordinary  witness,  a  dentist  would 
probably  be  entitled  to  fees  on  the  scale  usually 
given  to  professional  men.  As  an  expert 
witness,  the  fees  are  a  matter  of  arrangement, 
and  care  should  be  taken  to  obtain  a  binding 
arrangement  as  to  these,  if  possible  in  writing, 
and  a  clear  understanding  as  to  the  person 
liable  to  pay  them. 

It  is  always  advisable  to  obey  a  subpoena, 
even  where  it  is  known  that  the  only  evidence 
to  be  given  under  it  is  to  be,  or  can  be,  from  the 
circumstances,  "  expert  evidence  ". 

In  the  case  of  medical  men  giving  evidence, 
they  are  often  faced  with  the  alternative  either 
of  giving  evidence  which  will  disclose  matters 
learned  under  the  seal  of  professional  secrecy, 
or  of  refusing  to  give  evidence  as  being  a  breach 
of  professional  secrecy.  The  same  alternatives 
may  be  presented  to  the  dentist.  It  should  lie 
remembered  that  there  is  no  such  thing  as 
professional  privilege  known  to  the  law,  either 
in  the  case  of  medical  men  or  dentists,  and 
neither  medical  nor  dental  secrets  can  be  kept 
in  the  witness  box.  This  has  been  settled  law 
since  the  Duchess  of  Kingston's  case*  when 
the  privilege  was  claimed  and  denied.  The 
law  in  this  respect  conflicts  absolutely  with  the 
'■  law  ",  i.  e.  cu.stom.  of  professional  secrecy,  and 
with  the  law  in  France  and  America.  If  faced 
with  this  alternative,  the  practitioner  should 
state  that  the  facts  giving  the  answer  to  the 
question  asked  him  were  made  known  to  him 
or  observed  by  him  under  the  ])ledge  of  pro- 
fessional secrecj',  and  should  make  it  clear  that 
he  only  answers  because  ordered  so  to  do  by 
the  Court.  In  Kitson  v.  Playjair,  Hawkins  J. 
stated  that  the  Court  might  in  some  cases  refuse 
to  commit  a  medical  man  for  contempt  in  refusing 
to  reveal  confidences. 

'    Tai/lor  on  Evidence,  pars.  1419-20. 

=  Powell  on  Evidence,  edit.  Blako  Ocigers  (1910). 

»  Taylor's  jW f(/ica;j»ri»/<r»</cnce(  1910),  Vol.  I,  p.  50. 

«   20 "How,  State  Trials,  p.   73.').      Wilmn  v.   liastall, 
4  T.K.  p.  "60.     Rex  v.  CUbbons.  1  C.  &  P.  97.     Broad  v. 
Pitt,  3  C.  &  P.  518. 
25* 


It  should  be  observed  that  no  witness  need 
answer  a  question  if  the  answer  would  incrimin- 
ate the  witness  himself. 

The  imaginary  "  privilege  "  hereinbefore 
referred  to,  must  not  be  confused  with  the 
"■  privilege  "  attaching  to  communications  as 
to  patients,  made  not  in  court,  but  mider 
circumstances  and  to  persons  which  render 
them  privileged  and  not  actionalile  as  defama- 
tory. Care  should  be  exercised  in  comnumi- 
cations  made  to  the  members  of  a  patient's 
family,  or  to  the  employers  of  patients,  for  it 
should  be  reinemlered  that  it  is  for  the  judge  to 
determine  the  question  of  "  privilege  "",  and  he 
will  require  strong  evidence  that  a  sense  of  duty 
was  the  only  compelling  motive. 

If  to  an  action  for  defamation  the  defence  of 
"  justification  "  be  set  up,  it  must  be  proved 
not  only  that  the  words  used  were  true,  but  also 
that  they  were  used  without  malice,  and 
■■  malice  ",  in  law,  "  may  mean  anything  showing 
the  least  indication  of  personal  motives,  or 
anjiihing  showing  a  want  of  due  consideration 
for  the  aggrieved  person."  '  Generally,  on  the 
subject  of  expert  evidence,  it  is  to  be  regretted 
that  the  qualifications  of  "experts"  are  not 
more  strictly  inquired  into,  since  the  lack  of 
this  often  leads  (1)  to  persons  of  little  standing 
giving  evidence  in  a  sense  conflicting  with  that 
of  the  recognized  authorities  on  the  subject  at 
issue ;  (2)  to  persons  of  high  standing  and 
knowledge  in  one  branch  of  a  subject  giving 
expert  evidence,  to  which  undue  value  is 
attached,  on  other  branches  of  that  subject  of 
which  they  are  not  really  fully  cognisant." 

Inasmuch  as  the  tribunal  must  listen  to  all 
those  who  present  themselves  or  are  presented 
as  "experts",  "testimony  is  daily  received  in 
our  courts  as  '  scientific  evidence  '  to  which  it 
is  almost  profanation  to  apply  the  term  ;  as 
being  revolting  to  common  sense,  and  incon- 
sistent with  the  commonest  honesty  on  the  part 
of  those  by  whom  it  is  given."  ' 

THE  DENTIST  AND  THE  LAY  PUBLIC 

In  most  of  his  legal  relationships  with  other 
members  of  the  public  the  dentist  stands  on 
the  same  footing  as  his  fellows,  and  is  under 
no  special  obligations  and  derives  no  S])ecial 
advantages  from  his  professional  status.  There 
are  some  legal  duties  and  privileges,  however, 
with  \\hich  his  profession  may  tend  to  make 
him  more  familiar  than  is  the  layman. 

s  Dixon  &  Mann,  Forensic  Medicine. 

«  .Jolm  Hunter  publicly  expressed  his  regret  that  he 
liad  not  devoted  more  time  to  the  study  of  poisons 
lieforo  venturing  opinions  in  court.  Best.  Principles 
of  the  Law  of  Evidence,  p.  430. 

•  Best.  Principles  of  the  Law  of  Evidence,  p.  491. 
Uthed.  (1911). 


778 


Negligence  or  Malpraxis 

The  practitioner  is  especially  liable  to  actions 
for  negligence.  There  are  a  large  number 
of  such  actions  brought — and  many  others 
threatened — in  many  cases,  it  is  to  be  feared, 
merely  as  a  means  of  evading  payment  for 
professional  services  rendered.^  NegHgence  by 
a  dental  practitioner,  as  by  any  other  person, 
is  an  offence  at  common  law,'-  and  it  has  been 
well  defined  as  "  the  omission  to  do  something 
which  a  reasonable  man,  guided  by  those  con- 
siderations ^\•hich  ordinarily  regulate  the  con- 
duct of  human  affairs,  would  do,  or  doing 
something  which  a  prudent  and  reasonalile  man 
would  not  do  "  ;  ^  or  "  the  neglect  of  the  use  of 
ordinary  care  and  skill  towards  a  person  to 
whom  the  defendant  owes  the  duty  of  observing 
ordinary  care  and  skill,  by  which  the  plaintiff 
[without  contributory  negligence  on  his  part] 
has  suffered  injury  to  liis  person  [or  property]  ".^ 

What  is  the  negligence  for  which  the  prac- 
titioner will  be  liable  ?  It  may  be  grounded  on 
two  charges,  viz.  want  of  skill,^  and  want  of 
care.  It  may  consist  of  error  in  diagnosis,  or 
neglect  in  treatment.  An  erroneous  diagnosis, 
followed  by  the  correct  treatment  for  a  case 
so  diagnosed,  is  less  culpable  than  erroneous 
diagnosis  followed  by  the  incorrect  treatment 
for  a  case  so  diagnosed.'^ 

Wliat  is  the  amount  of  skill  which  must  be 
sho^vn  by  the  qualified  practitioner  ? 

The  answer  to  this  question  is  for  any  par- 
ticular case  one  of  fact  rather  than  of  law. 
The  law,  however,  lays  down  in  general  language 
general  rules,  which  must  be  applied  to  the  facts 
of  a  particular  case. 

And,  first,  the  highest  possible  degree  of  skill 
is  not  exigible. 

■'  Every  person  who  enters  a  learned  pro- 
fession undertakes  to  bring  to  the  exercise  of 
it  a  reasonable  degree  of  care  and  skill.  He 
does  not  undertake,  if  he  is  an  attorney,  that  at 
all  events  you  shall  gain  your  case,  nor  does  a 
surgeon  undertake  that  he  will  perform  a  cure, 
nor  does  he  undertake  to  use  the  highest  possible 
degree  of  skill."  ' 

A  medical  man  and,  therefore,  a  dentist,  is 

1  It  is  perhaps  needless  to  observe  that  there  exist 
many  societies  for  the  legal  defence  and  protection  of 
practitioners  against  such  and  other  claims;  and  that 
it  is  not  unusual  for  articles  of  partnership  between 
practitioners  to  stipulate  that  the  members  shall  belong 
to  such  a  society. 

'  The  offence  of  malpraxis  was  known  to  the 
Egyptian  and  Roman  Law.  Oppenheimer.  Trans- 
actions of  Medico-Legal  Society,  l'J09— 10. 

^  Blythe  v.  Birmingham  Waterworks  Co.,  11  Exch. 
781,  784. 

»  Per  Brett,  M.R.,  in  Heaven  V.  Pender,  11  Q.B.D.  507. 

'.  Seare  v.  Prentice,  8  East,  348. 

•  Hamilton  &  Godkin,  Legal  Medicine,  p.  577. 
•     '  Lampkier  v.  Phipos  (1838),  C.  &  P.  475  per  Tindal 
C.J. 


not  answerable  "  because  some  other  practi- 
tioner might  jDossibly  have  shown  greater  skill 
and  knowledge,  but  he  was  bound  to  have  that 
degree  of  knowledge  and  skill  which  could  not 
be  defhied,  but  which,  in  the  opinion  of  the 
jury,  was  a  competent  degree  of  skUl  and 
knowledge"  .* 

The  skill  required  is  not  that  of  the 
"thoroughly  educated  ",  or  of  the  "  moderately 
educated  ",  or  of  the  "  well  educated  ",  but  that 
of  "  the  average  of  the  thorough,  the  well,  and 
the  moderate  ".  '  The  professional  man  under- 
takes that  he  has  "  the  ordinary  skill  and  know- 
ledge necessary  to  perform  his  duty  towards 
those  resorting  to  him  in  that  character  ".^" 

The  standard  of  skUl  (and  diligence)  required 
from  the  dental  practitioner  in  a  particular  case 
is,  therefore,  "  that  of  the  ordinary  average 
registered  practitioner,  unless  there  are  in  the 
particular  case  circumstances  that  point  to  some 
other."'! 

The  jury  give  their  verdict  as  to  whether  in 
the  particular  case  a  proper  degree  of  skUl  was 
shown,  and  are  guided,  in  general,  to  their 
conclusion  by  the  evidence  of  practitioners 
given  before  them  as  to  what  is  a  proper  degree 
of  skill ;  nor,  in  general,  do  the  jury  demand 
the  possession  of  a  degree  of  skill  beyond  the 
capacity  of  an  ordinary  practitioner  of  average 
industry  and  ability. 

What  degree  of  care  is  demanded  of  the 
practitioner  ?  The  answer  would  seem  to  be 
the  same  as  to  the  question  as  to  the  degree  of 
skill ;  namely,  the  ordinary  average  degree  of 
care  required  from  an  ordinary  practitioner  in 
the  particular  circumstances  of  the  case. 

Certain  criteria  of  malpraxis  are  laid  down  by 
the  text  writers  which  have  been  summarized 
as  follows —  '^- 

(1)  Has  the  injury  been  inflicted  by  .  .  .  the 
act  of  the  [practitioner]  ? 

(2)  Did  the  [practitioner]  exhibit  ignorance 
of  those  rules  which  are  common  property  of 
the  profession  or  wliich  have  been  sufficiently 
established  to  become  knowai  to  him  with 
ordinary  watchfulness  of  the  advances  of  his  art  ? 

(3)  Did  [the  practitioner]  depart  from  the 
established  rules  bearing  upon  the  particular 
case  in  an  unjustifiable  or  extraordinary  degree  1 

It  should  be  noted  with  regard  to  the  third 
criterion,  that  if  the  practitioner  does  not  follow 
the  usual  practice,  it  is  a  question  for  the  jury 
whether  he  is  a  scientific  inquirer  (m  departing 
from  the  usual  practice  in  favour  of  some  other) 
or  whether  he  is  "a  mere  ignorant  pretender  ".^^ 

8  Richv.  Pierpoint  (1862),  3  F.  &  F.  35,  per  Erie,  QJ. 

'  Smothers  v.  Hanks,  11  Am.  R.  141  (America). 
•"  Bevon,  On  Negligence  in  Law,  p.  1186. 
"   Ibid.,  p.  1170. 

'-  Hamilton  &  Godkin,  Legal  Medicine. 
"  Bevon,  Negligence,  1158. 


79 


Treatment  is  not  necessary  to  give  rise  to 
a  claim  for  damages  for  negligence.  Mere 
examination  is  sufficient,  if  the  consequences 
of  such  examination,  if  negligently  conducted, 
give  rise  to  damage. ^ 

"  Treatment  involving  probabilities  of  danger 
cannot  be  applied  to  a  patient  without  com- 
munication to  him,  and  his  consent,"  thougli  a 
'■general  intimation"  of  "pain  or  danger" 
to  arise,  is  sufficient,  without  a  scientific  exposi- 
tion of  the  case  to  the  patient.-  But  when  a 
patient  is  anaesthetized,  and  incapa})le  of  giving 
consent,  the  strongest  pos.sible  reasons  should 
be  present  before  an  operation,  to  ^hich  consent 
has  been  given,  be  extended. 

The  specific  cases  of  negligence  most  com- 
monly alleged  against  the  dental  profession  are  : 
the  extraction  of  a  wrong  tooth,  dislocation  of 
the  lower  jaw  when  misapplied  force  is  used, 
fracture  of  the  jaw,  haemorrhage,  sepsis,^  injury 
or  death  from  anaesthesia  ;  and  it  may  be  noted 
that  it  has  been  decided  (in  America)  that  the 
suffering  of  a  tooth  to  slip  do«n  the  throat  of 
a  patient  is  sufficient  evidence  of  negligence  to 
carry  the  case  to  a  jury.* 

Generally,  \\  ith  regard  to  these  specific  cases 
it  may  be  observed  that  the  mere  occurrence  of 
one  of  the  conditions  above  mentioned,  e.  g. 
haemorrhage,  is  not  sufficient  to  give  ground  of 
action  ;  it  must  be  sho^^■n  that  it  occurs  through 
the  ignorance  or  negligence  of  the  practitioner. 
For  example  the  extraction  of  a  wTong  tootli  may 
be  due  to  a  tooth  adliering  closely  to  the  carious 
tooth  proper  to  be  extracted.  In  arriving  at 
a  decision  as  to  what  constitutes  negligence, 
"  it  is  the  province  of  the  judge  to  inform  the 
jury  for  what  species  or  degree  of  negligence  [a 
dentist]  was  properly  answerable,  and  what 
duty  in  the  case  before  them  was  cast  upon 
him,  either  by  the  statute  or  the  practice  of  the 
court,  but,  having  done  this,  it  was  right  to 
leave  to  them  to  say,  considering  all  the  circum- 
stances, and  the  evidence  of  the  practitioners, 
whether  he  was  liable."^ 

A  dental  practitioner  is  responsible  for  injury 
to  a  patient  caused  by  want  of  proper  skill  in 
his  assistant.® 

A  qualified  assistant  or  locum  (enens  is  him- 
self liable  for  negligence  to  a  patient.  But  the 
governing  body  of  a  hospital  or  a  (mirsing) 
association  is  not  liable  for  malpraxis  of  their 
staff  if  they  have  selected  properly  qualified 
persons.' 

'  Be\on,  Negligence,  11G4.  ^  /b,y.,  HCl. 

'  Douglas  Knocker,  Accidents  in  their  Medico-Legal 
Aspect,  1st  ed.  Chapter  on  "  Accidents  to  Teeth 
and  Jaws",  pp.  772-8,  Norman  G.  Bonnott. 

*  Keily  v.  Cotton,  1  City  Court  New  York,  439. 

'   In  re  Maasei^  and  Careij  (1884),  20  CD.  459. 

«  Hancke  v.  Hooper,  7  C.  &  P.  81. 

'  Hall  v.  Lees  (1904),  2  K.B.  002.  Evans  v.  Mayor 
of  Liverpool  (1906),  1  K.B.  160. 


But  a  member  of  a  staff  of  a  hospital  is  not 
liable  for  negligence  for  which  lie  is  not  person- 
ally responsible,  e.  g.  the  negligence  of  a  nurse 
or  other  person  in  negligently  carrjdng  out  the 
use  of  a  remedy  directed  or  orders  given  by  him.** 

An  unregistered  practitioner,  "if  not  known 
to  be  unregistered  must  attain  the  standard  of 
skill  of  a  registered  practitioner  at  the  place 
and  in  the  circumstances  where  the  services  are 
rendered ;  if  known  to  be  unregistered  then 
the  skill  of  his  profession,"^  i.  e.  the  skill  which 
he  •  professes  "  or  announces  to  the  person  em- 
ploying him ;  otherwise  he  is  lialile  for  negligence  ; 
or,  following  the  analogy  of  an  unqualified  medical 
man,  if  unqualified  and  known  to  be  such,  he  is 
perhaps  Uable  "  for  the  lack  of  diligence  and 
skill  belonging  to  an  ordinary  unprofessional 
person  of  common  sense  ''.''■" 

It  is  no  defence  to  an  action  for  malpraxis 
that  the  services  rendered  were  voluntary  and 
no  fee  was  paid. 

Anaesthesia 

The  fact  that  anaesthetics  are  now  so  fre- 
quently employed  in  dental  operations  renders 
the  practitioner  specially  liable  to  (1)  the  risks 
following  a  death  Ijy  anaesthesia,  (2)  charges, 
often  of  a  blackmailing  character,  brought  by 
female  patients. 

With  regard  to  the  first  class  there  is  no 
recorded  case  in  which  either  "a  criminal  or 
civil  successful  action  has  been  brought  on 
account  of  a  death  from  general  anaesthesia  ".^^ 

The  subject  is  one  of  peculiar  interest  to  the 
dentist,  insomuch  as  he  often  both  administers 
the  anaesthetic  himself  and  also  performs  the 
operation.  The  law  does  not  forbid  the  ad- 
ministration of  an  anaesthetic  by  an  unqualified 
person,  but  the  opinion  of  the  medical  profession 
on  the  .subject  of  the  administration  of  anaes- 
thetics appears  to  be  crystallized  in  the  following 
propositions '^-,  which  may  form  a  groundwork 
for  legislation. 

(1)  No  one  but  a  properly  qualified  person 
should  be  permitted  to  administer  an 
anaesthetic.  A  qualified  dentist  should 
be  considered  "  properly  quaUfied  "  to 
administer  nitrous  oxide  gas  without 
holding  a  medical  quaUfication. 

*  Perionowsky  v.  Freeman,  4  F.  &  F.  977. 

•  Beven,  Negligence,  1170.  Dickson  v.  Hygienic 
Institute  (1910),  1  S.L.T.  p.  HI.  Held:  A  company 
carrying  on  dental  business  by  means  of  imqualified 
assistants  is  liable  in  damages  to  person  injured,  since 
by  their  contract  with  the  person  injured  (i'.  e.  their 
"profession")  they  had  imdertnken  to  supply  the 
ordinary  skill  of  registered  practitioners. 

'"  Quoted  by  Bevon  from  Wharton,  Negligence,  29. 
But  see  Dickson  v.  Hygienic  Institute,  cit.  sup. 
"  Taylor,  Medical  Jurisprudence,  Vol.  I,  p.  102. 
•*   Vide  Taylor,  Medical  Jurisprtidence,  1910  ed. 


780 


(2)  It  is  arguable  whether  an  inquest  should 

always  be  held  on  a  death  from  anaes- 
thesia. 

(3)  If  an  inquest  be  held,  in  the  case  of  the 

surgeon  or  dentist  operating  with  an 
anaesthetist  assisting  him,  need  the 
conduct  of  the  surgeon  or  dentist  be 
called  in  question  at  the  inquest,  and 
should  not  the  anaesthetist  alone  be 
summoned  ? 

(4)  Should  a  distinction  be  drawn  between 

the  various  general  anaesthetics  ? 

A  BUI  to  regulate  the  practice  of  anaesthetics 
and  restrict  it  to  registered  persons  is  now  under 
consideration  by  the  Home  Office ;  it  has  (sub- 
ject to  modification  in  detail)  received  the 
approval  of  the  General  Medical  Council,  the 
British  Medical  Association,  and  the  British 
Dental  Association,  and  other  scientific  and  pro- 
fessional bodies  concerned  with  the  subject. 

From  the  purely  legal  standpoint  it  is  ad- 
visable that  to  avoid  the  risks  attendant  upon  the 
use  of  anaesthetics,  the  practitioner  should  only 
operate  cither  with  the  assistance  of  another 
practitioner  as  anaesthetist  or  in  any  case  in  the 
presence  of  a  person  other  than  the  patient. 

The  second  class  of  risks  to  which  reference 
has  been  made  above  deserves  jiassing  mention. 
Charges  of  assault  upon  female  patients  while 
anaesthetized  are  often  made  for  the  purpose  of 
(1)  blackmail,  (2)  to  avoid  payment  of  fees. 
Many  are  not  reported,  but  there  is  little  doubt 
that  some  innocent  practitioners  have  suffered 
punishment  at  the  hands  of  the  law. 

Such  charges  are  also  frequently  made  in  all 
good  faith  by  modest  females ;  ^  a  female  under 
the  partial  influence  of  an  anaesthetic,  may 
mistake  a  forcible  attempt  to  restrain  her  while 
she  is  passing  through  the  preliminary  stage  of 
excitement,  for  an  attempt  upon  her  person.^ 

A  case  is  recorded^  where  a  woman's  tooth 
was  extracted  while  she  was  under  the  influence 
of  chloroform  and  in  the  presence  of  her  affianced 
hu.sband.  She  could  hardly  be  convinced,  on 
regaining  consciousness,  that  the  dentist  had 
not  made  an  attempt  upon  her  chastity. 

The  charge  may  also  sometimes  be  made 
owing  to  a  fear  of  such  a  contingency  pre- 
existing in  the  patient's  mind,  prior  to  the 
operation,  and  making  a  deep  impression  on  the 
mind,  which  impression  may,  after  retrrn  to 
consciousness,  change  into  a  belief  that  a  reality 
has  given  rise  to  the  impression. 

To  avoid  such  risks,  it  is  the  general  practice, 

'  "  Anae.sthetics  stimulate  the  sexual  functions  and 
the  ano-genital  region  is  the  last  to  give  up  its  sensitive- 
ness." Bull,  of  the  Medico-Legal  Society  of  New  York, 
May  and  December,   1881. 

'  Taylorj  Medical  Jurisprudence. 

s  Ihid. 


and  one  which  has  much  to  recommend  it,  not 
to  administer  an  anaesthetic  to  a  female  patient, 
save  in  the  presence  of  a  witness. 

Recovery  of  Fees 

The  recovery  of  his  fees  by  a  dental  prac- 
titioner is  regulated  by  the  ordinary  law  of 
contract.  There  is  no  professional  "law  ",  i.  e. 
custom,  ^^•hich  disables  a  dentist,  as  such,  from 
suing  for  his  fees. 

It  should  be  remembered  that  a  master  is  not 
liable  to  pay  the  fees  incurred  by  his  servant.* 

An  infant  in  law,  i.  e.  a  person  under  the  age 
of  twenty-one  years,  is  liable  only  for  "  neces- 
saries ",  and  no  exhaustive  list  of  necessaries  can 
be  compiled,  since  the  question  as  to  what  are 
necessaries  is  to  be  decided  having  regard  to  the 
infant's  condition  in  life  and  to  his  actual  re- 
quirements at  the  time.  The  judge  determines 
whether  the  thing  supplied  can  reasonably  be 
termed  a  necessary ;  if  he  thinks  there  is  doubt 
he  leaves  the  question  to  the  jury ;  if  he  thinks 
there  is  no  doubt,  he  himself  decides.* 

"  Physic  "  is  a  necessary,^  and,  therefore, 
presumably,  reasonable  dental  attendance,  and 
mechanical  appliances.  But,  quaere,  whether, 
e.  g.  the  supply  of  a  gold  plate  to  an  infant  of 
small  means  would  be  a  "necessary",  if  a 
vulcanite  plate  would  have  answered  the  purpose 
equally  well.  Medical,  and  therefore  probably 
dental,  attendance  is  a  necessary  if  given  to  the 
wife  or  children  of  an  infant.' 

A  married  woman  may  now  contract  with  a 
dentist  (or  any  one  else)  as  though  she  were  a 
feme  sole.  If  she  do  so  contract  (not  as  agent 
for  her  husljand),  the  dentist  may  obtain  judge- 
ment against  her  for  his  fees,  which  judgement 
"  will  bind  all  separate  property  [of  the  married 
!  woman]  «hicli  she  may  at  the  time  when  she 
enters  into  the  contract,  or  thereafter,  be 
possessed  of  or  entitled  to,  and  will  also  be  en- 
forceable against  all  property  wliich  she  may 
thereafter  while  discovert  be  possessed  of  or 
entitled  to,  Imt  it  will  not  be  enforceable  against 
property  \\hich  at  the  time  of  the  contract  the 
married  woman  is  restrained  from  anticipating. "^ 

The  judgement  can  only  be  enforced  against 
her  property,  not  her  person  ;  she  cannot  be 
imprisoned  under  the  provisions  of  the  Debtors 
Act,  1869.*     If  carrying  on  a  trade  separately 

'  Wennall  v.  Adney,  3  B.  &  P.  247.  SeUen  v.  Nor- 
man, 4  C.  &  P.  80. 

'  Ryder  v.  Womhwell,  L.R.  3  Ex.  90,  and  on  appeal 
4  Ex.  32. 

«  Co.  Litt.  172,  a.      L.  3,  c.  i,  sec.  259. 

'  Turner  v.  Trishy,  1  Str.  168. 

'  Montague  Lush  (now  Lush  J.),  Law  of  Husband 
and  Wife,  p.  358.  Married  Woman's  Property  Acts, 
1882  and  1893.  (45  &  46  Vict.,  cap.  75;  56  &  57  Vict., 
cap.  63,  sec.  1.)  But  after  April  1,  1914,  see  Bankruptcy 
and  Deeds  of  Arrangement  Act  1913. 

«  Scott  V.  Morley,  20  Q.B.D.  120. 


781 


from  her  }iusband,  and.  after  tlie  1st  day  of 
April.  1914,  wlu'tlier  separately  or  not,  she  can 
be  made  bankrupt  ^  (but  not,  prior  to  the  1st 
day  of  April  llll-l,  by  means  of  a  bankruptcy 
notice  ^). 

But  in  most  ordinary  cases  where  a  dentist 
contracts  ^^•ith  a  married  \\oman,  he  would  give 
her  credit  as  agent  for  her  husband,  and  whether 
he  can  recover  his  fees  may  turn  on  \\liether  she 
has  (n)  actual  authority  to  pledge  her  husl)and"s 
credit,  or  {h)  ostensible  authority  so  to  do. 

A  wife  has  actual  authority  to  pledge  her 
husband's  credit  for  bare  necessaries  to  keep  her 
in  health  if  her  husband  does  not  supply  them 
or  supply  her  with  means  to  purchase  them, 
and  (quaere),  she  has  no  means  of  her  own. 

Medical  attendance  is  a  "  necessary  ",*  there- 
fore presumably  such  dental  attendance  and 
appliances  as  are  necessary  to  keep  the  wife  in 
health  are  "necessaries",  and  she  has  actual 
authority  to  pledge  her  husband's  credit  for 
these  (unless  (quaere)  she  has  means  of  her  own),^ 
and  the  dentist  can  recover  against  the  husband. 
iSed  quaere,  whether  the  cost  of  a  gold  plate  or 
gold  or  porcelain  filling  could  be  recovered 
against  the  husband  as  a  bare  necessary  to  keep 
the  wife  in  health,  if  \-ulcanite  or  plastic  filling 
\\  ould  have  answered  the  purpose. 

But  the  position  of  the  parties  in  life  may  be 
such  that  gold  plates  and  fillings  and  expensive 
operations  and  treatment  \\ould  be  held  to  be 
necessaries  for  persons  in  that  position.  And  if 
the  dentist  seeks  to  recover  again.st  the  husband 
for  these,  on  the  ground  that  the  wife  had  the 
actual  authority  of  her  husband  to  pledge  his 
credit  for  them,  it  must  be  remembered  that 
(apart  from  "  bare  necessaries  ")  the  authority 
to  pledge  the  husband's  credit  for  ordinary 
nece.'^saries  is  only  a  "  mere  presumption  "  in 
the  dentists'  favour.^  and  that  such  authority 
is  only  a  question  of  fact,  it  is  jmrna  facie 
authority,*  and  if  it  be  showai  not  to  exist,  e.  g.  if 
the  husband  has  forbidden  his  ^^•ife  to  pledge 
his  credit,  or  made  her  an  allowance,  then  the 
husband  is  not  liable,  whether  the  dentist  knew 
of  the  husband's  prohibition,  or  of  the  allow- 
ance, or  not. 

1  In  re  Gardiner,  20  Q.B.D.  249.  Aft<T  the  1st  day 
of  April,  1914,  every  married  woman  who  carries  on  a 
trade  or  business  whether  separately  from  her  husband 
or  not  shall  be  subject  to  the  bankruptcy  laws  as  if  she 
were  a  jemr  sole.  Bnnkruptoy  and  Deeds  of  Arrange- 
ment Act,  1913.      (:j  and  4  (len.  V.  cap.  :!4.  ss-e.  12.) 

2  In  re  Frances  Handiord  cfc  Co.,  1  Q.B.D.  (1899)  5r>6, 
After  the  1st  day  of  April,  1914,  a  married  woman 
carrying  on  trade  or  business  will  Ve  amenable  to 
proceedinfts  by  way  of  bankruptcy  notice, 

'  Todd  v.  Stokes,  1  Salk.  lit)";  Aldia  v.  Chapman. 
Scl.  N.P.  2;!2;  Beale  v.  Arab  in,  36  L.T.N.S;  Hanson 
V.  (Irady,  13  L.T.N.S.  3fi9. 

*  Dehenham  v.  Mellon,  6  App.  Cas.  31. 

'  Edw.  Jonks,  Husband  and  Wife  in  the  Lair,  p.  5.5. 
Lu'ih,  cil.  sup.  p.  38(i. 

'  Lush,  Law  of  Husband  aixd  Wife.  p.  391. 


Therefore  if  the  dentist  relies  on  the  actual 
authority  of  the  wife  to  pledge  her  husband's 
credit,  he  does  so  at  his  own  risk,  except, 
semble,  in  the  case  of  what  may  be  called  "  bare 
dental  necessaries  "  sufficient  to  keep  her  in 
health,  and  (quaere),  she  having  no  means  of 
her  own, 

Tlie  tendency  of  recent  decisions '  is  to  limit 
the  right  of  the  wife  to  render  her  husband 
liable  on  the  ground  of  her  having  actual 
authority  to  pledge  his  credit,  and  to  increase 
the  risk  to  the  creditor  who  gives  her  credit,  of 
failure  to  recover  against  her  husband. 

But  the  husband  may  render  himself  liable 
by  allowing  his  wife  "ostensible  authority  "  to 
pledge  his  credit.  The  most  usual  way  in  which 
a  husband  thus  holds  out  his  wife  as  having 
ostensible  authority  to  pledge  his  credit  is  by 
paying  her  bUls,^  and  here  the  practitioner  is 
on  safer  ground,  for  if  the  husband  pays  his 
wife's  dentist's  bUI  once,  the  dentist  may, 
ordinarily,  safely  continue  to  give  her  credit  as 
her  husband's  agent,  until  the  husband  gives 
him  specific  notice  not  to  do  so.  and  a  general 
advertisement  by  the  husband  that  he  will  not 
be  responsible  for  his  wife's  debts,  is  not  suffici- 
ent where  he  has  paid  her  bills,  unless  specifically 
brought  to  the  notice  of  the  dentist. 

The  dentist  may  have  to  prove  to  whom  he 
gave  credit,  i.  e.  whether  he  really  held  the  wife 
to  be  his  debtor,  or  considered  her  husband  to 
be  so ;  and  in  this  connection  it  should  be 
remembered  that  the  entering  of  the  name  of 
either  the  wife  or  the  husljand  in  the  books  is 
not  conclusive  evidence  that  the  credit  was  given 
to  the  person  whose  name  is  so  entered.^ 

It  should  also  be  remembered  that,  in  the 
case  of  a  wife's  contracts  for  necessaries,  "  it 
will  ordinarily  be  inferred,  in  the  absence  of 
evidence  to  the  contrary,  that  she  contracted  as 
agent  for  her  husband  only,  and  not  on  account 
of  herself  alone,  or  with  her  husbrtnd,  even 
where  she  has  separate  property,"  '" 

If  a  wife  or  servant  calls  in  a  dentist  to 
attend  to  a  member  of  the  household  in  a  case 
of  emergency,  then,  following  the  analogy  of 
medical  cases,  the  father  of  the  family  is  prob- 
ably liable  for  the  dentist's  fees," 

Though  a  master  is  not  liable  to  pay  for 
medical  attendance  to  his  servant  (unless  the 
master  agrees  to  pay  for  it)  yet  .slight  evidence 
may  be  sufficient  to  "fix  the  master  with  liability, 
e.  g.  interference  as  between  the  servant  and 
the  servant's  doctor,  or  the  calling  in  his  (the 

'  Morelv.  Westmorland  (1904),  A.C.  11;  Paquin  v. 
Beauclerk  (190ti),  A.C.  1(50. 

s  Debenham  v.  Mellon  (cit.  sup.);  Jolly  v.  Eees, 
C.B.N.S.  628. 

'  Paterson  v.  Gandasequi,  15  East,  62. 
"  Lvish,  Law  of  Husband  and  Wife,  p.  369;  Morel  v. 
Weslmorland  (cit.  sup.) ;   Paquin  v.  Beauclerk  (cit.  sup.). 
"  Cooper  v.  Phillips,  4  C.  &  P.  581. 


782 


master's)  own  medical  man  to  attend  on  a  sick 
servant.^ 

SimUar  principles  would  probably  be  applied, 
mutatis  mutandis,  in  the  case  of  a  dental  practi- 
tioner. The  contract  to  pay  the  fees  of  a 
dentist  being  a  parol  contract,  camiot  be  en- 
forced by  action  after  six  years  have  expired 
from  the  date  on  which  the  cause  of  action 
arises  ^  (unless  the  remedy  be  revived  by  a 
written  acknowledgement  of  the  debt  or  by  part 
payment). 

Undue  Influence 

The  medical  man  is  brought  into  such  close 
and  confidential  relations  with  his  patients  that 
the  law  views  with  suspicion  (1)  gifts  by  the 
patient  made  i7iter  vivos,  (2)  voluntary  settle- 
ments by  the  patient,  (3)  gifts  by  will  of  the 
patient,  and  such  bequests  are  often  set  aside 
on  the  ground  of  undue  influence.  It  is  sul)- 
mitted  that  in  the  mere  relationship  of  dentist 
and  patient  there  is  no  frima  facie  ground  for 
suggestion  of  undue  influence  in  such  classes  of 
cases. 

Workmen's  Compensation  and  Insurance 

The  dental  practitioner  as  an  employer  of 
labour,  e.  g.  in  the  case  of  his  hired  assistants, 
his  servants  engaged  in  attendance  on  his 
patients,  and  in  the  case  of  his  mechanics,  is 
bound  by  the  provisions  of  the  Workmen's 
Compensation  Act,  1906,  in  regard  to  compensa- 
ting such  emj^loyees  or  their  dependants  for 
(1)  injury,  or  (2)  death  from  accidents  arising 
out  of  and  in  the  course  of  their  employment. 
The  practitioner  is  also,  as  an  employer,  subject 
to  the  provisions  of  the  National  Insurance  Act, 
1911,  Part  I,  (1  &  2  Geo.  V,  cap.  55). 

THE  DENTIST  AND  HIS  FELLOW 
PRACTITIONERS 

Partnership 

Partnership  is  the  relation  that  subsists 
between  persons  carrying  on  a  business  in 
common  with  a  \'iew  of  profit,  and  is  chiefly 
regulated  by  the  Partnership  Act  of  1890.^ 

Partnerships  between  members  of  the  dental 
profession  are  not  essentially  differentiated  from 
the  general  law  regulating  these  relations,  but 
there  are,  in  the  case  of  partnerships  between 
dentists,  certain  terms  or  provisions  of  the 
partnership,  usual  or  advi.sable,  to  which  atten- 
tion may  be  drawn  as  being  peculiar  to  partner- 
ship between  persons  practising  a  profession. 

The  mutual  rights  and  duties  of  partners  are 
defined  by  agreement  between  the  partners,  or 

1  Sellen  v.  Norman,  4  C.  &  P.  80. 
^  21  Jac.  I.  cap.  16,  sec.  3. 
'  53  &  54  Vict.  cap.  39. 


in  the  absence  of  agreement  are  defined  by 
the  Partnership  Act. 

They  are  u.sually  embodied  in  writing  in 
articles  of  partnership,  which  may  be  varied 
by  the  consent  of  all  the  partners,  and  such 
consent  may  be  either  expressed,  or  inferred 
from  a  course  of  dealing.* 

Tlie  partnership  articles  contain  the  main 
terms  of  the  agreement  between  the  partners, 
and  in  the  usual  case  would  contain  in  detail 
provisions  as  to  most,  if  not  all,  of  the  points 
following,  with  such  variations  as  in  each  case 
may  prove  necessary  or  desirable.  The  proposed 
duration  of  the  partnership  should  be  stated ; 
the  style  or  name  under  which  the  partnership 
is  to  be  carried  on  ;  the  amount  of  premium 
(if  any)  to  be  paid  by  one  partner  to  another ; 
the  shares  that  each  partner  is  to  take  in  the 
partnership  property,  and  the  share  that  each 
partner  is  to  take  in  the  profits,  and  what  is 
meant  by  profits  should  be  carefully  defined  so 
as  to  avoid  questions  arising  as  to  what  deduc- 
tions, etc.,  must  be  made  before  "  profits  " 
are  ascertained.  Li  the  case  of  dental  instru- 
ments and  appliances  owned  by  a  partner 
these  may  be  taken  by  the  firm  at  a  valuation 
and  become  partnership  pioperty. 

Dental  jjujjils  should  be  taken  by  a  partner 
only  with  the  consent  of  the  other  partners,  and 
the  premiums  received  from  them  may  be 
partnership  property,  or  not.  Assistants  (or 
workmen)  should  only  be  engaged  with  the 
consent  of  all  partners.  The  fees  received  by 
each  partner  should  become  partnership  pro- 
perty ;  but  legacies  and  gifts  of  specific  articles 
(not  money)  from  patients  may  remain  the 
property  of  the  individual  ^^artner  to  whom 
they  are  bequeathed  or  given. 

Provision  should  be  made  as  to  \\hether  the 
premises  in  which  the  business  is  carried  on  be 
considered  joint  property  or  not.  Provision 
should  be  made  as  to  whether  the  profits  of 
appointments  held  by  the  several  jsartners  be 
considered  joint  or  several  property,  and  pro- 
vision should  be  made  as  to  the  acceptance 
of  appointments  during  partnership,  e.  g.  that 
such  be  only  accepted  with  the  consent  of  all 
partners. 

Formal  clauses  as  to  the  proper  attendance 
and  conduct  of  the  partners  in  the  business  are 
useful ;  and  pro\'ision  should  be  made  that  no 
partner  take  part  in  any  other  business  without 
consent,  or  carry  on  any  other  profession.  A 
f)artner  should  be  required  to  covenant  not 
to  assign  or  charge  his  share  in  the  business. 
Provision  should  be  made  as  to  the  keeping  of 
the  patients  of  each  partner  separate. 

Provision  should  be  made  as  to  the  bankers 
of  the  i^artnership,  and  that  all  books  of  account, 

*  Partnership  Act,  1890,  sec.  19. 


783 


attendance  books,  and  all  business  letters,  bills, 
and  papers,  be  kept  at  the  premises  in  which 
the  business  is  to  be  carried  on,  and  Ije  open 
to  insjaection  of  the  partners. 

Provision  should  be  made  for  an  annual  (or 
other)  account  being  taken,  and  that  each 
partner  be  entitled  to  draw  on  account  of  his 
share  of  profits  to  an  amount  specified.  Inas- 
much as  the  business  is  not  one  of  a  general 
commercial  nature, ^  dentists  would  have  no 
implied  authority  to  sign  or  accept  bills  of 
exchange  so  as  to  bind  their  partners,  but  a 
proviso  may  be  inserted  in  the  articles  expressly 
denying  their  authority. 

Provision  may  also  be  inserted  providing  that 
in  the  case  of  the  illness  or  incapacity  of  a 
partner  he  should  provide  a  locum  tenens  at 
his  own  expense  or  otherwise. 

A  partner  should  be  forbidden  to  lend  partner- 
ship money,  or  to  give  monetary  credit  to  any 
one  against  whom  he  has  been  warned  by  his 
partners,  or  any  of  them. 

Provision  should  be  made  for  the  determina- 
tion of  the  partnership  by  effluxion  of  time,  by 
notice,  or  in  the  event  of  the  death  of  a  partner, 
and  it  may  be  provided  that  in  the  event  of 
the  death  of  a  partner  a  specified  sum  may  be 
paid  to  his  executors  for  goodwill,  as  well  as 
his  share  of  the  profits  calculated  up  to  his 
death,  and  as  well  as  his  share  of  the  partnership 
assets  at  death,  such  share  to  be  ascertained 
by  valuation.  It  may  be  provided  that  a 
retiring  or  expelled  partner  be  restrained  from 
practice  in  competition  with  his  partner  or 
partners,  and  this  for  any  length  of  time,^  or 
at  any  time,  and  \nthin  wide  limits  of  distance. 
The  test  for  an  agreement  in  restraint  of  trade, 
(and  such  a  provision  comes  under  this  category), 
is  whether,  taking  all  the  facts  into  considera- 
tion, the  restraint  imjiosed  is  reasonable  and 
necessary  for  the  protection  of  the  party  seeking 
to  impose  the  restraint,  and  if  so,  the  restraint 
will  be  upheld,  if  not  contrary  to  the  interests 
of  the  public."  In  Mallan  v.  Ma;/  *  a  dentist 
was  restrained  from  practising  throughout  the 
whole  of  London. 

A  restraint  against  practice  in  "  Chester  or 
within  sixteen  miles  by  nearest  road  from 
Chester  Cross  or  any  place  within  the  boundaries 
of  Birkenhead  "  has  been  held  good.'' 

In  the  case  of  a  junior  partner  being  taken 

'  Story  (HI  Ag(>ncy,  124;  Bank  of  Australasia  v. 
lireillat  (1847),  0  Moo.  P.C,  p.  193:  Kx  parte  Darling- 
ton d-c.  lianhinq  Co.  (1864),  4  D.,7.S.  p.  585. 

=  Palmer  v.  Mallet,  36  Cli.D.  411. 

3  NordenjcU  v.  Maxim  Nonlenjelt  Co.  (1804),  A.C. 
535;  Underwood  <t-  Son  v.  Barker  (1899),  1  fli.  300; 
Haynes  v.  Doman  (1890),  2  Ch.  13. 

>  11  M&  W.,  053. 

'^  Bullin  V.  Teece,  1  Set.  180.  In  Horner  v.  Graves, 
7  Bing.  735,  one  hundred  miles  round  York  hold  not 
necessary  for  protection  and  so  void. 


and  paying  a  premium,  it  may  be  advisable, 
acting  in  his  interest,  to  provide  that  a  propor- 
tionate part  of  such  premium  be  repaid  in  the 
event  of  the  partnership  being  determined 
within  so  many  years,  otherwi.se  than  by  the 
retirement  or  expulsion  of  the  junior  partner. 

In  the  event  of  a  partnershi])  between  a 
senior  partner,  well  established  in  practice,  who 
is  taking  in  a  junior  partner,  an  option  may  be 
given  to  the  senior  partner  to  retire  after  so 
many  years  on  giving  notice  to  his  junior 
partner,  and  to  give  notice  to  the  junior  partner 
to  purchase  the  interest  of  the  senior  partner  so 
retiring  in  the  partnersliip,  and  that  if  the  junior 
partner  do  not  so  purchase  that  interest,  the 
senior  partner  may  sell  it  to  some  other  person. 

In  such  a  jiartnership  provision  may  also  be 
made  for  the  retirement  of  the  junior  partner. 

It  is  common  to  stipulate  that  diiTerences 
between  the  partners  as  to  the  meaning  and 
intent  of  the  partnership  articles  and  as  to 
partnership  matters  generally  shall  be  adjusted 
by  arbitration  under  the  Arbitration  Act,  1889. 

For  breaches  of  the  agreement  to  be  com- 
pensated by  damages,  a  fixed  sum  as  liciuidated 
damages  should  be  specified ;  in  this  manner, 
the  necessity  may  often  be  avoided  of  proving, 
it  may  be  laboriously  and  expensively,  the 
actual  extent  of  damage  suffered  by  breach. 

Provision  should  be  made  as  to  the  eiTect,  e.  g. 
by  dissolution,  on  the  partnershipof  "profes.sional 
misconduct  "  by  any  of  its  members.  By  the 
Dentists  Act,  1878,'*  a  registered  dentist  con- 
victed of  felony  or  misdemeanour,  or  who  has 
"  been  guilty  of  any  infamous  or  disgraceful 
conduct  in  a  professional  respect ",  may  have 
his  name  erased  from  the  register  by  order  of 
the  General  CouncU. 

Advertising  has  been  held  to  come  within 
the  definition  of  such  conduct,  and  the  General 
Council  may  strike  oiT  the  register  a  practitioner 
guilty  of  advertising.'  The  General  Medical 
Council  have  laid  down  certain  criteria  which 
govern  their  decision  as  to  whether  the  adver- 
tising he  such  as  to  call  for  the  infliction  of 
this  penalty.  The  questions  to  be  answered 
are  :  (a)  is  the  advertising  w  idespread.  (h)  is  it 
depreciatory  of  other  practitioners,  and  (c)  is  it 
not  merely  ministerial  ? 

It  has  been  held  to  be  professional  misconduct 

«  41  &  42  Vict.  cap.  33,  soc.  13. 

■  Partridge  v.  The  General  Council  of  Medical  Educa- 
tion and  Registration.  (1S02)  57  ,1.P.,  p.  4.  Where  a 
person  lins  liceu  rcfiistevod  under  tlie  .Act  as  a  licentiate 
of  a  medical  authority  the  withdrawal  of  his  diploma 
by  that  medical  authority  does  not,  ipso  facto,  render 
him  liable  to  bo  era.sed  from  the  Dentists'  Register,  Ex 
parte  Partridge.     (1887),  19  Q.B.IJ.  437.  (C.  A.) 

Erasing  under  section  13  of  Dentist's  Act  is  a  discre- 
tionary Act,  and  not  merely  ministerial,  and,  in  absence 
of  nuilico.  no  nctioi\  lies  against  Coimcil.  though  discre- 
tion may  liavo  boon  erroneously  exorcised.  Partridge 
V.  General  Council,  etc.  (1890),  25  Q.B.D.  90. 


784 


(\\  itliin  the  meaning  of  a  clause  in  a  partnership 
deed  providing  for  dissohition  in  the  event 
of  ■"  professional  misconduct  "  by  a  partner), 
where  one  partner,  as  director  of  a  limited 
company,  was  a  party  to  advertisements  issued 
by  the  company,  stating  (1)  that  all  instru- 
ments used  by  the  company  were  sterilized, 
(2)  that  to  prevent  scandal  a  trained  lady 
nurse  was  always  present  at  interviews  with 
and  operations  on  female  patients.^ 

A  dentist  «ho  attends  patients  sent  to  him 
by  an  unqualified  practitioner,  if  he  act  in 
conjunction  \\ith  him  so  as  to  enable  him  more 
readily  and  successfully  to  practise  as  an  un- 
qualified man,  is  guilty  of  the  professional 
offence  of  "covering". 

Sale  of  Practice 

The  sale  of  a  practice  is  in  law  the  selling  of 
the  introduction  of  the  dentist  who  sells  to  the 
dentist  who  buys. 

In  purchasing  a  practice  the  terms  of  the 
introduction  are  of  paramount  importance,  and 
in  the  agreement  for  the  sale  the  commencement, 
the  character,  and  the  duration  of  the  introduc- 
tion should  be  clearly  defined. 

Provision  should  be  made  in  an  agreement 
for  the  sale  of  a  practice  that  if  the  selling  dentist 
fails  in  liealth  or  dies  during  the  term  of  the 
introduction  a  proportionate  abatement  should 
be  made  in  the  purchase  money.  If  an  intro- 
duction be  promised,  and  the  seller,  being  in  bad 
health  when  he  contracted  to  sell,  die  before 
carrying  out  the  introduction,  which  may 
extend  over  a  period  of  years,  a  proportionate 
part  of  the  premium  paid  can  be  recovered 
back.- 

It  is  doubtful  if  the  court  can  grant  specific 
performance  of  a  contract  to  give  an  intro- 
duction,^ i.  e.  whether  the  court  can  order  the 
practitioner  who  has  agreed  to  give  an  introduc- 
tion to  do  so  under  pain  of  imprisonment  if  he 
refuse.  For  the  introduction  is  the  rendering 
of  personal  services,  and  the  court  \\i\\  not  grant 
specific  performance  of  an  agreement  if  the 
court  camiot  supervise  the  execution  of  it, 
which  is  obviously  impossible  in  the  case  of 
introducing  patients,  a  matter  that  the  court 
could  not  adequately  supervise  without  defeat- 
ing the  object  of  the  supervision. 

The  amount  of  premium  payable,  the  time 
and  the  method  of  payment,  should  also  be 
clearly  set  out  in  an  agreement  for  sale  of 
practice.  On  the  part  of  the  buyer,  stipulation 
should  be  made  that  the  seller  retire  from 
practice  altogether,  or  from  practice  within  the 
district  in  which  the  practice  sold  is  situate. 

1  Clifford  V.  Timms,  H.L.  (E)  (1908),  App.  Cas.  12; 
Clifford  V.  Philips,  H.L.  (E)  (1908),  App.  Cas.  15. 
*  Mackenna  v.  Parkea,  3(i  L.J.  Ch.  366. 
3  May  V.  Thomson,  20  Ch.D.  705. 


If  the  agreement  contains  a  stipulation  that 
the  seller  will  not  directly  or  indirectly  enter 
into  competition  with  the  buyer,  then  the 
seller  may  not  come  into  the  area  of  the 
practice  sold,  even  if  called  in  by  patients 
resident  within  that  area.* 

If  the  seller  has  liberty  to  practise  elsewliere 
than  in  the  district  of  the  practice  sold,  he 
should  bind  himself  not  to  solicit  his  old  patients 
to  follow  him,  and  whether  he  retires  from 
practice  altogether,  or  only  from  practice 
within  the  area  of  the  practice  sold,  he  should 
bind  himself  not  to  introduce  another  practi- 
tioner to  his  old  patients. 

Provision  should  be  made  as  to  the  lease  of 
the  premises  in  -tthich  the  practice  is  to  be 
carried  on,  e.  g.  it  should  be  assigned  to  the 
purchaser. 

Provisions  wUl  be  necessary  as  to  the  furni- 
ture, fittings,  and  dental  appliances.  If  the 
buyer  is  to  jjay  for  the  practice  by  giving 
to  the  seller  a  share  of  the  profits  during  a 
course  of  years  (an  arrangement  that  wUl  not 
necessarily  constitute  the  seller  a  partner  of 
the  buyer '')  the  purchaser  cannot  cease  to 
f)ractise,  and  so  escape  the  liability  to  pay  the 
share  of  profits,  but  is  taken  to  agree  to  continue 
practising  for  the  term  of  years  mentioned.*^ 
In  the  case  of  the  seller  holding  appointments 
that  he  will  relinquish  on  sale  of  practice,  he 
may  bind  himself  to  use  his  best  endeavours 
to  obtain  for  the  buyer  such  appointments. 
It  is  also  useful  to  provide  that  disputes  con- 
cerning an  agreement  for  sale  of  a  practice  he 
referred  to  arbitration.  A  widow,  who  is  also 
executrix  of  her  deceased  husband,  who  was 
a  dentist,  cannot  sell  the  goodwill  of  her  de- 
ceased husl>and's  practice  and  the  advantage 
of  an  introduction  to  his  late  patients,  and  retain 
all  the  purchase  money  for  herself  beneficially, 
even  though  she  is  herself  to  give  the  introduc- 
tions, and  the  buyer  says  he  relied  on  introduc- 
tions being  done  by  her  personally,  but  she  must 
apply  part,  at  any  rate,  of  the  purchase  money 
as  part  of  the  testator's  estate ;  therefore, 
semble,  the  goodwill  of  the  business  of  a  deceased 
dentist  is  capable  of  having  some  value  put 
upon  it  as  belonging  to  his  executors.'  To  buy 
the  x^ractice  of  an  unqualified  man.  and  associate 
with  him  so  as  to  obtain  introductions  to  his 
old  patients,  constitutes  the  professional  offence 
of  "  covering  ". 

Hire  of  Assistants 

The  contract  with  an  assistant  may  advan- 
tageously contain  agreements  on  the  part  of 

'  Bogers  v.  Drury,  57  L.J.  Ch.  504. 
*  Partnership  Act,  1890,  sec.  2,  subsec.  3  E. 
«  Mclntyre  v.  Bcchler,  32  L.J.  C.P.  254. 
'  Smale  v.  Graves,  19  L.J.Ch.  (N.S.)  157. 


785 


the  assistant  not  to  disclose  the  professional 
secrets  of  his  principal ;  to  keep  and  render  true 
and  proper  accounts  of  all  work  done  and  fees 
received  ;  not  to  attend  any  patient  for  any  other 
practitioner  without  tiie  consent  of  his  principal : 
not  to  cairy  on  or  he  engaged  in  carrying  on 
another  jjractice  nor  to  give  dental  advice 
gratuitously  or  on  his  own  account. 

Provision  should  be  made  as  to  payment  or 
non-payment  of  salary  during  the  illness  of  the 
assistant,  it  being  remembered  that  if  his  re- 
muneration do  not  exceed  £250  per  annum,  he 
comes  within  the  provisions  of  the  Workmen's 
Compensation  Act,  1!K)6,  and,  if  his  remuneration 
do  not  exceed  £IfiO  jjer  annum,  within  the  pro- 
visions of  the  National  insurance  Act  1911, 
Part  I.  The  duration  of  the  agreement  and 
provisions  for  its  determination  should  be 
adequately  specified,  and  in  the  case  of  an 
assistant  wlio  is  to  be  appointed  deputy  in 
any  appointment  held  by  his  principal,  pro- 
vision should  be  made  for  his  resigning  the 
deputyship  on  the  termination  of  the  contract 
of  assistancy. 

In  consideration  of  the  hiring,  it  is  competent 
to  insert  in  the  hiring  agreement  a  restraint 
against  practice  by  the  assistant,  after  the 
termination  of  the  contract  of  assistancy,  within 
the  area  of  the  principal's  practice.^ 

In  the  case  of  Palmer  v.  Mallet,-  an  injunction 
was  granted  to  restrain  an  assistant  to  a  firm 
of  surgeons,  who,  after  the  dissolution  of  the 
fii'ni,  continued  to  act  as  assistant  to  one  of  the 
old  members  of  the  firm,  contrary  to  the  terms 
of  a  bond  into  which  the  assistant  had  entered 
with  the  firm,  and  by  which  he  had  undertaken 
not  to  carry  on  business,  directly  or  inchrectly, 
alone  or  in  partnership  \\ith,  or  as  assistant  to, 
any  other  person  or  firm  ;  and  it  was  held  that 
"  carrying  on  business  as  assistant  of  a  surgeon  " 
was  "carrying  on  business  as  a  surgeon",  and 
in  that  respect  differed  from  a  trade.  Mutatis 
mutandis,  it  is  submitted  that  the  same  con- 
siderations would  apply  in  the  case  of  a  dental 
assistant. 

The  assistant  should  be  required  to  enter 
into  a  bond  to  pay  a  certain  sum  as  liquidated 
damages  in  the  event  of  a  breach  of  his  agree- 
ment not  to  compete  with  his  former  ])rinci])al, 
such  fixed  sum  to  constitute  the  measure  of 
damages.^     To  permit  an  unqualified  assistant 

»  Mallan  v.  May,  11  M.  &  \V.  003. 

2  30  Ch.D.  411. 

3  Rawlinaon  v.  Clarke,  14  M.  &  W.  187 


to  draw  or  fill  teeth  constitutes  the  professional 
offence  of  "  covering  ",  unless  this  is  done  under 
direct  personal  supervision. 

Dext.\i.  Apprentices  or  Pupils 

The  practitioner  may  find  it  convenient  to 
take  an  apprentice  or  a  dental  pupil  (who 
intends  afterwards  to  qualify  himself  for 
practice)  whom  he  will  instruct  in,  and  to  whom 
he  will  give  opportunities  of  ac{|uiring  knowledge 
of.  the  mechanical  part  of  dentistry;  or  he  may 
take  an  apprentice  for  the  same  purpose,  who 
only  intends  to  become  a  dental  mechanic. 

Apprenticeship  is  usually  though  not  neces- 
sarily evidenced  by  deed,  and  is  cletermined  by 
the  death  or  permanent  incapacity  *  of  either 
party. 

In  the  old  indentures  of  apprenticeship,  e.  g. 
in  the  form  used  in  the  City  of  London,  the 
covenants  on  the  part  of  the  master  included 
an  obligation  to  provide  the  apprentice  with 
board,  lodging,  and  medicine.  In  the  case  of 
(inter  alios)  dental  apprentices,  who  do  not 
reside  wdth  their  master,  this  is,  of  course, 
omitted ;  a  small  wage  may  be  given  in  the 
later  years  of  his  apprenticeship  in  the  case  of 
an  apprentice  who  is  to  become  a  dental 
mechanic  oidy. 

The  master  should  covenant  to  give  instruc- 
tion, and  that  part  of  the  premium  will  be 
returned  in  the  event  of  the  death  of  the  master 
before  the  indentures  have  expired. 

On  behalf  of  the  apprentice,  his  father  or 
guardian  should  be  joined,  and  covenant  to 
provide  him  w  ith  proper  board,  lodging,  clothing, 
and  medicine,  and  to  make  good  thefts  by  the 
apprentice,  or  chattels  wilfully  broken,  spoiled, 
or  destroyed  liy  the  ap])rentice,  who  should 
undertake  to  serve  the  master  and  obey  his 
orders  and  instructions. 

It  is  submitted  that  an  agreement  with  an 
apprentice  or  pupil  who  is  under  age  may  not 
contain  a  restraint  against  practice  on  the 
part  of  the  apprentice  or  pupil.'' 

P.B.H. 

«  Farrow  v.  ]yilson  (1809),  L.R.  C.P.  744. 

^  Dc  Francesco  v.  Barnum,  43  Cli.  D.  105.  Capes  v. 
Million  (1820).  2  Russ.  357.  Corn  v.  Maltlietvs  (1893), 
1  Q.U.  310.  Contra  (cliota  per  Kekewich  J.),  vido 
Richards  v.  Whillain  (1892),  00  L.  T.  p.  095.  scd  quaere. 
Where  contract  is  one  of  paid  ?ervico,  vide  Fellows  v. 
Wood,  59  L.  T.  p.  513.  Evans  v.  Ware  (1892),  3  Cli. 
502. 


786 


TABLE    OF   CASES   CITED   IN   APPENDIX 


Aldis  V.  Chapman 

Attorney  General  v.  Appleton 

„     "  „        V.  Aslibourne  Recreation 

Ground  Co. 
„  „        V.  Birmingham    etc.    Drainage 

Hoarti 
„  „        V.  Cluirchill's  Veterinary  Sana 

torium,  Ltd. 
„  „        V.  Myddleton's,  Ltd. 

V.  G.  C.  Smith,  Ltd. 
„  ,,        V.  Shrewsbury  (Kingsland) 

Bridge  Co. 
„  ,,        r.  Wimbledon  Plouse  Estate  Co 

Bank  of  Australasia  v.  Breillat 

Barnes  r.  Brown ""3, 

Beale  v.  Arabin  . 

Bellerby  v.  Heyworth 773. 

Blythe  i'.  Birmingham  Waterworks 

Bremridge  v.  Hume   .... 

British  Dental  Association  v.  Drew 

,,  ,,  ,,  J'.  Smith 

,,  ,,  V.  Wickman 

Broad  v.  Pitt       . 
Brown  v.  Wliitlock     . 
Bullin  V.  Teece   . 
Byrne  v.  Rogers 


PAGE  OF 
APPENDIX 

781 
775 


Capes  V.  Hutton 
Carter  v.  Boelim 
Clifford  V.  Philips 
„       V.  Tiinms 
Cooper  V.  Phillips 
Corn  V.  Matthews 


Darlington  etc.  Banking  Co.,  Ex  parte 
Davies  v.  Makuna       .... 
Debenham,r.  Mellon 
De  Francesco  v.  Barnum 
Devonport  Corporation  i'.  Tozer 
Dickson  v.    Hygienic  Institute 
Duchess  of  Kingston's  Case 
Duffy  V.  Jaffe.     <S'ee  O'Duffy  XK  Jaffc. 


Elmslie  v.  Paterson    . 
Evans  v.  Mayor  of  Liverpool 
,,       V.  Ware    . 


Farrow  v.  Wilson 
Fellows  V.  Wood 
Frances  Handford  &  Co., 

Gardiner,  In  re  . 


In  re 


Hall  V.  Lees 
Hancke  v.  Hooper 
Handford  Frances, 

ford. 
Hanson  i\  Grady 
Haynes  v.  Doman 
Heaven  v.  Pender 
Horner  v.  Graves 


/((  re.       See  Frances  Hand 


776 

776 
776 
776 

776 
776 

783 
774 
781 
774 
778 
774 
773 
773 
773 
777 
77.5 
783 
774 

785 
776 

784 
784 
781 
785 

783 
772 
781 
785 
776 
779 
777 


774 
779 

785 


785 
781 


Jolly  V.  Rees 


781 
783 
778 
783 

781 


PAGE  OP 
APPENDIX 

Keily  v.  Cotton 779 

Kitson  V.  Playfair 777 

Lamphier  v.  Phipos 778 

La    Soci^t^  anonyme  des  anciens  etablissements 

Panhard,  etc.     See  Societe  (La)  anonyme. 

Lee  V.  Griffin 772 

Mackenna  r.  Parkes 784 

Mallan  v.  May 783,  785 

Massey  and  Carey,  In  re 779 

May  i\  Thomson 784 

Mclntyre  v.  Bechler 784 

Minter  v.  Snow 774 

Morel  i\  Westmorland 781 

Nordenfelt  v.  Maxim  Nordenfelt  Co.       .        .        .  783 

O'Duffy  V.  Jaffe 775 

Palmer  v.  Mallet 783,  785 

Panhans  c  Brown 774 

Paquin  v.  Beauclerk 781 

Partridge  i:  The  General  Council    ....  783 

Partridge,  Ex  parte 783 

Paterson  i\  Gandasequi 781 

Perionowsky  v.  Freeman 779 

Pharmaceutical  Society  i:  Mercer  ....  774 
Phannaceutical  Society  v.  London    &    Provincial 

Supply  Association  775 

Rawlinson  v.  Clarke 785 

Rex  I'.  Gibbons  ........  777 

Rex  (Rowell)  v.  Registrar  of  Joint  Stock  Com- 
panies for  Ireland 775 

Rich  V.  Pierpoint 778 

Richards  v.  'Wliittam 785 

Robertson  v.  Hawkins 773 

Rogers  v.  Drury 784 

Royal  College  of  Veterinary  Surgeons  v.  Robinson  774 

„  „  ,,  ,,         V.  Collinson  774 

Ryder  v.  Wombwcll 780 


780, 


Scott  V.  Morley  . 

Seare  v.  Prentice 

Sellen  v.  Norman 

Smale  v.  Graves 

Smothers  v.  Hanks     . 

Society  (La)  anonyme  des  anciens  Etablissements 
Panhard  et  Levassor  v.  Panhard  et  Levassor 
Motor  Co 


Todd' I'.  Stokes   . 
Turner  v.  Trisby 


Underwood  &  Son  v.  Barker    . 


Wennall  v.  Adney 
Wilson  V.  Rastall 


780 

778 
782 
784 


781 
780 


783 

780 

777 


INDEX 

The  letters  a  </«<;  b  re/i-r  to  Hit  left  and  right  luind  columns  of  the  page  respectively. 


Abnormalities    of   deciduous   teeth 
(.fee  Deciduous  teeth),  436. 
permanent    teeth    {see    Permanent 
teeth),  38 
AbnormaUties  of  position  of  teeth  and 
abnormal     development     of 
associated    parts    (see    Arch 
and  Malocclusion),  52 
aetiological  factors,  68 
classification,  82 
deciduous  dentition  [sec  Deciduous 

teeth).  13.56 
diagnosis,  143 
introduction,  52a 

malocclusion  [see  Malocclusion),  526 
pathological  influences,  756 
treatment,  145« 
appliances,  107 
extraction,  1476 
general  objects  of,  145rt 
mechanical,  age  for.  1476,  1496 
preliminaries  of,  15i)a 
retention,  jirinciples   of,   150o, 

227o 
surgical,  1616 
Abrasion,  304tt 
Abscess, 

acute,  course  and  signs  of,  6725 
diagnosis,  673rt 
treatment.  6746 
alveolar,  4386,  671 
apical,  438rt 

chronic,  course  and  signs  of,  673rt 
diagnosis,  6736 
treatment,  6746 
injection,  674a 
pathology,  67 1« 
residual,  674a 
sequelae  of,  676rt 

treatment  by  ionic  medication,  5216 
Absorption  of, 

deciduous  teeth.  276 
permanent  teeth,  316,  36rt 
Actin<miycosis,  767 
Adenoids    and    defective    growth    of 
arch,  61« 
effect  on  lower  arch,  786 
malocclusion,  536,  61a,  109a 
rickets,  76a 
Affections   of   the   third    mandibular 
molar  (see  Third).  33 
absorption  of  adjacent  tooth,  36a 
anatomical  relations,  33a 
All-gold  crown,  5616 
AUoys  (see  Amalgams),  386a 
Amalgam,  357o.  386a 
ageing  or  annealing,  389a 
alteration  in  form,  3876 
copper,  391a 
mercury,  amount   and   distributicm 

of.  3S8a 
metallography  of,  3966 
mixinc  of,  3926 
oral  fluids,  action  on.  3896 
pacliing,  methods  of.  394a 
palladium,  392a 
physical  examination  of.  395a 
■silver-tin  allov  moilitied.  390a 


Amalgam  [continued) — 
stress, 

crushing,  3886 

djmamometer  for  measuring,  3966 
mechanical  changes  iluc  to,  38S6 
Amalgam  or  matrix  crown,  559a 
Amalgamation,  386a 
Amputating  the  crown  of  a  tooth,  5496 
Anaesthesia, 
injection,  665o 
local,  664a 

pulp  for  removal  (see  Pulp),  4595 
Anchorage, 

in  moving  teeth,  1.546,  1796 
reciprocal,  1806 
simple,  1806 
stationary,  181a 
Anchylosis,  4956 

aetiology  and  pathology,  496a 
Angle's  modified  bow  for  movement 

of  incisors,  2386 
Angle  of  lower  jaw, 
at  birth,  15a 
at  second  year,  26a 
Antiseptic  technique  in  dental  surgery, 

363a 
Antrum  (see  Jlaxillary  sinus) 
Apical  foramina,  time  of  closure,  309a 
Appliances  for  moving  teeth,  169a  ^ 
advantages  and  disadvantages,  1706 
construction  of.  22.56 
fixed,  169o,  1726 
removable,  169a 
Arch  (see  (dso  under  AbnormaUties  aiul 
Malocclusion), 
abnormal  formation  due  to  develop- 
mental defects  of  bone,  99a 
conditions    first    showing    them- 
selves while  deciduous  molars 
are  in  place,  99a 
fan-shaped  lower  incisors,  936, 

946,  1016,  105a 
overlapping  of  lower  incisors, 

101a 
post- placement  of  upper  incisors 

1005 
rotation  of  incisors,  996,  1045 

treatment,  203a.  215a 

V-shaped  areli.  996,  1056 

treatment,  102a 

conditions   arising   after   loss 

deciduous  molars,  1036 

canine      buccal     eruption 

maxilla,  104a 
premolar     lingual     or     buccal 

eruption,  1046 
U-shaped  arch,  1056 
treatment.  106a 
abnormal      relationship      between 
upper  anil  lower  arches,  1076 
vertical  occlusion  variations,  1076 
close  bite,  1146 

anterior  deformity.  1 1  I'' 

treat  ment .  11 .5a 

posterior  deformity,  1  I5a 

treatment,  1 1-56 

open  bite.  S9a.  lOSa 

treatment.  1126 

787 


of 


in 


Arch,  estimation  of  in  abnormalities, 
14.55 

expansion  of,  1536 

relationship    between     upper    and 
lower  arches.  11176 
Arrested  caries,  3026 
Arsenic,  454a 

application  and  sealing  in  of,  456a 

devitaUzation  of  pulp  by,  4546 

removal  of,  4576 
Ash"s  facing  for  re-facing  crowns,  5915 
Atresia  of  lips  and  gums,  56 
Atrophy  of  pulp  (see  Pulp),  3176 
Attrition,  304a 

pathology  of,  304a 

pulp  inflammation  as  a  sequence, 
4305 
Auricles,  accessory,  96 

Bacteria  of  caries  (see  Caries).  2626, 
263a.  2656,  2706,  272a6,  2996 
of  the  mouth.  256a 
bacilli,  2666 

non-patliogenic,  2716 
blastomyces,  2785 
cocci,  259a 

pathogenic,  2596 
non-pathogenic,  2626 
leptothrieae,  280a 
spirilla.  2736 
streptothricae,  2775 
Badcock's  screw  for  expansion,  1695, 

170a,  1716 
Bands,  1726 

cementation  of,  1776 
fitting  of,  176a 

making,  technique  of,  173a,  222a 
materials  used  in  construction,  1756 
size  of,  226a5 
j    Bifid  uvula,  4a 
I    Bite,  close,  1145 

1        impression-taking      for     crownnig, 
5545 
jumping  the,  1266 
open,  89o.  108a 
Bleaching  of  teeth  by  ionic  medication. 

523a 
Bloom's  facings  for  crowns,  5906 
Blue  line  on  gums,  738a 
Bone, 

defective  grow-th  due  to  adenoids, 
61a 
i  to  nasal  obstruetiiui,  76a 

developmental  defects  (see  -Arch) 
Bows,  174rt 

accessories,  175a 

adjustment,  178a 

.'Vnglc's  modification,  2386 

hooks  on,  225a 

materials  used  in  construction.  1756 

shape   of.   considerations   affecting, 

1786 
spurs  on,  225a 
Bracket  fixture  for  crown  niaking.o9oa 
Branchial  fistula.  8a 
Bridge-work, 

introduction,  602 


BRIDGE-WORK 


788 


CONCUSSION  OF  THE  TEETH 


Bridge-work  (continued) — 

cast  sectional  bridges,  631 

cementing  of,  6266 

fixed  bridge,  to  malie.  608a 

impressions  for,  6066 

porcelain  bridges,  6286 

posts  for,  616a 

pressure-casting  applied  to,  6256 

removable  bridge,  to  make,  617a 
abutments  for,  6206 

repairing  of,  6266 

saddle  bridges,  623a 
Bridge-  and  crown-work. 

pulp  management  in,  464a 
Bryant's  crown  or  bridge  repair  pro- 
cess, 5926 
Buccal  tubes, 

bands,  direction  of,  1776 
position  of,  177a 
Biittner  crown,  5856 


Calcification  of, 
cementum,  126 
deciduous    teeth,    126,    146,     15a6, 

25a 
permanent  teeth.  126.  25a 
pulp,  3186 
Calculus,  2506 

cause  of  deposit,  251a 

composition,  251a 

in  ducts  and  glands,  253o 

treatment,  2536 
sub-gingival,  2516 
treatment,  2526 
Callahan's  treatment  for   constricted 

root-canals,  4706 
C'ancrum  oris,  7386 
Canines, 

approximal    cavities    in    for    gold 

filling,  3806 
buccal  eruption  in  maxilla.  104a 
regulation  of,   1046 
major  tooth  niovcmmts,  182a 

buccal  mo\'ement,  upper  or  lower, 
both  sides,  183a 
fixed  appliance.  1836 
removable  appliance.  184a 
retention,  184a 

fixed  appliance,  230a 
removable  appliance,  231a 
buccal   movement    on    one    side 
only,  1836 
fixed  appliance,  184a 
removable  appliance,  1846 
retention,  185a 

fixed  appliance.  230a 
removable  appliance,  231a 
depression  movement  (.see  minor 

tooth  movement ),  204 
distal  movement  on   both  sides, 
189 
fixed  apphance,  192a 
removable  appliance,  193o 
by    head-gear    and    traction 
bar,  216a 
retention,  2335 

fixed  appliance,  234a 
removable  appliance,  2346 
distal  movement  on  one  side,  191a 
fixed   and  removable   appli- 
ances, 193a 
by   head-gear   and    traction 
bar,  216a 
retention,  2336 

fixed  appliance,  234a 
removable  appliance,  2346 


Canines  {continued) — 

major  tooth  movement  (continued) — 
distal  movement  in  lower  jaw, 
fixed     and     removable     ap- 
pliances, 193a 
retention, 

fixed  appliance,  235a 
removable  appliance,  2356 
elongation   in   both   jaws  simul- 
taneousl}-, 
fixed  appliance,  194a 
removable  appUance,  194a 
retention, 

fixed  appliance,  2366 
removable  appliance,  237a 
elongation  in  one  jaw  only, 
fixed  appliance,  1946 
removable  appliance,  195a 
retention, 

fixed  appliance,  2366 
removable  appliance,  237a 
lingual      movement,     upper     or 
lower,  both  sides, 
fixed  and   removable   appli- 
ance, 186a 
retention, 

fixed  appliance,  2315 
removable  appliance,  233a 
lingual  movement  on  one  side  only, 
fixed  and   removable   appli- 
ance, 1866 
retention, 

fixed  appliance,  2315 
removabfe  appliance,  233a 
voi»,i\on(seeminortooth'movement) 
minor  or  individual  tooth  movement, 
204 
buccal  mo\'ement,  204a 
fixed  appUance,  2106 
removable  apphance,  211a 
retention,  2046 

fixed  appliance.  230a 
removable  appliance,  231a 
depression,  213a 
retention,  213a 

fixed  appliance,  2356 
removable  appliance,  2366 
distal  movement, 

fixed  appliance,  2126 
removable  apjjhance,  213a 
retention,  2336 

fixed  appliance,  234a 
removable  appliance,  2345 
elongation,  213a 

fixed     and     removable     ap- 
pliance, 213a 
retention,  213a 

fixed  appliance.  2365 
removable  appliance,  237a 
lingual  movement,  214a 

fixed     and     removable     ap- 
pliance. 2115 
retention.  214'! 

fixed  appliance,  2316 
removable  appliance,  233a 
medial  movement,  214o 

fixed     and     removable     ap- 
pliance. 212a 
retention,  2336 

fixed  appliance,  234a 
removable  appUance,  2346 
rotation  movement,  215a 

fixed     and     removable     ap- 
pliance, 2136 
retention,  215a 

fixed  appUance,  237a 
removable  appliance,  2376 


Care    of    mouth    and    appliances    in 
treatment  of  regulation,  1605 
Caries. 

aetiology,  282a 
arrested,  3025 
bacteriology,  2995 

bacillus     mesentericus     group, 

272a 
bacillus  necrodentalis,  2706 
bacillus  proteus  group,  2726 
sarcinae,  263a 

staphylococcus  viscosus,  2626 
streptococcus  salivarius,  2656 
cementum  of,  302a 
chemical   constitution   of  teeth  in, 

2895 
chemistry  of,  282a 
civilization  factors,  287a 
deciduous  teeth  in,  allowing  move- 
ment, 136a 
diet,  influence  on,  285a 
microscopical  phenomena  in, 
dentine,  298a 
enamel,  297a 

Nasmyth's  membrane,  296a 
pathology  of,  295a 
pulp,  effects  of,  on,  311a 

exposure  of,  treatment,  452a 
inflammation    as   a   sequence, 
4365 
races  in,  288a 
relative  liabiUty  of  difierent  teeth 

to,  293a 
saUva  and  mucus,  influence  of,  291o 
susceptibility    and    immunity    to, 

2926 
unusual  situations  for,  303a 
treatment  b}', 

change  of  mouth  flora,  3345 
complications  in,  148a 
drugs,  334a 

excision  of  carious  foci,  3346 
filling,  336a 
preventive,  328a 
Carmiehael  crown,  5956 
Case's    contouring    apparatus,    157a, 

2176 
Cataphoresis,  519a 
Cavity  preparation,  general  principles, 

3445 
Cements, 

osteo-plastic,  397a 
oxy-chloride  of  zinc,  3996 
oxy-phosphate  of  copper,  400a 
oxy-phosphate  of  zinc,  397a 
oxy-sulphate  of  zinc,  3995 
silicious  cements,  400a 
Cementum, 
caries  of,  302a 
exposure  of,  439a 
hyperplasia  of,  439a,  4926 
Cervical  auricles,  96 
Chemiotaxis,  2495 
Children  and  their  teeth,  treatment, 

483a 
Chloro-pereha,   to   prepare   for   root- 
canal  treatment,  4786 
Clamps,    use   of    with   rubber   dam, 

342a 
Cleansing  the  teeth, 
artificial  means,  330o 
natural  means,  329a 
Cleft  palate,  4a 
Close  bite  and  treatment,  1145 
Coffin-spring  plate,  169a,  170a,  171a 
Colloid  degeneration  of  pulp,  3186 
Concussion  of  the  teeth,  524a 


CONSERVATIVE  OPERATIONS 


789 


ENAMEL  NODULES 


Conservative  operations  and  sterility 

of  field,  3636 
Contraction  and  expansion  of  amal- 
gams, 3876 
Copper  amalgam,  391a 
Cross  bite,  1346 

in  deciduous  dentition,  138a 
Crown-  and  bridge-work,  pulp  manage- 
ment in,  464(1 
Crowns,  537 

general  considerations,  537a 
principles  of,  5406 
all-goKl  crown,  5616 
amalgam  or  matrix  crown,  559a 
amputating  the  crown  of  a  tooth 

for,  .5496 
bracket  fixture,  595n 
broken  or  worn  crowns,  treatment, 

601a 
Biittner  crown,  5856 
Leon     WilUams's     modification, 
5866 
cap  crowns  porcelain-faced,  5716 
Carmichael  cro^\Ti,  5956 
collars  and  caps,  use  of,  in,  5426 
cutting  a  space  between  contiguous 

teeth,  oolo 
detachable-post  crowns,  580a 
dowel  hole,  preparation  of,  .549a 
enamelling  a  shell  crown,  571a 
fixing  of,  5976 

impression-taking  of  roots,  5546 
jacket  crowns,  572n 
Leon    AVilliams's    modification    of 

Biittner  crown,  5866 
Logan  crowns,  5786 
occlusion  of,  5436 
partial     cap,    pin,    and     porcelain 

crown,  5866 
partial  crowns,  596a 
pivot  crown,  587a 
porcelain  cast-gold  crown,  .589a 
porcelain,  ready-made,  5736,  5786 

to  make,  574a 
porcelain-faced  cap  crown,  5716 
porcelain-faced    cast-gold    crown, 

5896 
porcelain  facings  to  replace,  590a 
methods. 
Ash's,  5916 
Bloom's,  5906 
Bryant  s,  5926 
Leon  Williams's.  5916 
Logan's  slide,  .591a.  .5946 
long- pin  facings,  .592a 
Rose's,  591a 
Shriver's,  5936 
soldering  in  mouth,  .5936 
Steele's,  5906 
pressure-cast     gold     shell     crown, 

5706 
removing  of,  600a 
Richmond  crown,  581a 

with     readv-made     porcelain, 
5846 
roots,  preparation  of,  548« 
points  in  anatomy  of.  545a 
suitable  for  crowns.  5396 
sterilization  of  tooth  before  applica- 

tiim  of,  366a 
tube  crown,  .5836 
worn  or  broken,  treatment,  601a 
Crowning  split  teeth,  597a 
Crypt,    position    of,    and    total    dis- 
placement, 876 
treatment,  876 
Curve  of  Spec,  276 


Cysts,  116,740 
dental,  116,  749a 
dentigerous,  746a 
niultiloeular,  7426 


Dall's  inlays  and  the  fitting  of,  4086 
Dates  of  eruption, 
deciduous  teeth,  176 
permanent  teeth,  29a 
Death  of  pulp  in  moving  teeth,  153a 
Deciduous  dentition, 
abnormaUties  of,  1356 
cross-bite  and  its  treatment,  138a 
faulty  occlusion  in   incisor  region, 
1376 
in  molar  region,  136a 
fraenum  labii,  influence  on,  13.56 
malocclusion  in,  5,5a 
overbite.  136f/ 
rotation  of  incisors,  136a 
thumb-sucking,  1356 
treatment  of,  483a 
Deciduous  teeth.  156 

abnormalities  of,  436,  1536 
absence,  436,  866 
form,  45a,  856 
number,  436 
size,  436 
structure.  466 

supernumeraries  {see  S).  446 
absorption  of.  276 
calcification  of,  126,  146,  15a,  1,56, 

2.5a 
diseases   associated   with   eruption, 

19a 
treatment,  22a 
eruption  {sre  E) 
loss  of  all,  95a 
loss  of,  canines,  90a 
treatment,  906 
incisors,  896 

treatment,  906 
molars,  first,  916 
second, 92a 
treatment,  946 
loss  of  molars,  after  results,  1036 
loss,  premature,  896 
malocclusion     in     incisor     region. 
1376 
molar  region,  136a 
overbite,  136a 
retained,  84a 
rickets,  effects  of,  on,  186 
syphilis,  effects  on,  186,  466,  49a 
Deflected  septum,  77a 
Dental  cvsts,  116,  749a 
follicle",  12a 
papilla.  1 16 
Dental  .Jurisprudence    {ser    .luris])ru- 

dence),  771 
Dental  operating-room,   its  appoint- 
ments and  hygiene,  322 
Dentigerous  cyst,  116,  746a 
Dentine,  calcification  of,  126 
caries  of.  298a 
discoloration  of,  treatment  by  ionic 

medication,  .523a 
discoloured    covering    pulp,    treat- 
ment, 453a 
sensitive,  treatment  of,  341ia 
sterihzation  of.  in  treatment  of  root- 
canals,  3636 
obtunding  of,  by  ionic  medication, 
5206 
Dentition,  deciduous  (see   Deciduous) 
permanent  (see  Permanent) 


Detachable-post  crowns,  580a 
Development  of  jaw, 
after  birth,  156,  236 
before  birth,  la 

during  permanent  dentition.  296 
lower  jaw  (see  Meckel's  cart ila<»e). 
56 
teeth, 

after  birth,  1.56,  236 
before  birth,  la,  11a 
during  jjcrmanent  dentition,  296 
teeth-germs,  theories,  12a 
tongue,  7a 
visceral  arches,  la 
Developmental  flefects  of  bone  with 

abnormal  arch  (see  Arch) 
Devitalization  of  the  pulp,  4.546 
conditions  requiring  it,  461a 
Diagnosis  of  the  cause  of  pain,  43.5a 
aids  to,  in  odontalgia  ami  neurabda, 
443a 
Dilaccration,  49a 
Discoloration  of  teeth  due  to, 
devitalization,  4646 
e.Yternal  deposit,  2,54a 
Diseased  teeth  associated  with  reflex 

affections,  727 
Diseases  associated  with  eruption  of, 
deciduous  teeth.  l!)a.  22a 
permanent  teeth.  296 
oral  sepis,  702a 
of  the  mucous  membrane  of  mouth, 
736 
Dislocation  of  the  manilible,  699a 
teeth,  5246 

unerupted.  5266 
methods  of  retaining,  5256 
Displacement  of  the  teeth,  876 

treatment,  876 
Double  protrusion,  133a 
causes,  134a 
treatment,  134a 
retrusion,  1346 
Dowel  hole,  preparation  for  crowning, 

549a 
Dowels  for  crowning,  553a 
Dressings  for  teeth,  368a 
Dynamometer  for  amalgams,  3966 


Edentulous    patients,    neuralgia     in. 

4416 
Electro-therapeutics,  514a 
apparatus,  514a 
cataphoresis,  519a 
cautery,  518a 
electrodes,  5176 

electro-negative  ions,  519a,  520a 
electro-positive  ions,  520a 
ionic  medication,  5196 
treatment  by,  .5206 

of  abscess,  chronic  alveolar,  ,5216 
bleaching.  523a 
dentine,  obtunding  of,  5206 
neiH'algia,  .5236 
ppricxlontitis,  acute.  5216 
pulp,  anaesthesia  of,  5206 
pyorrhoea  alveolaris,  5216 
root -canals,  521a 
Elevation  or  elongation  of  teeth  from 

disuse,  108a 
Empyema  of  maxillary  sinus,  078 
Enamel, 

calcification  of,  126 
caries  of,  297a 
hypoplasia  of,  47a 
Enamel  nodules,  7.59a 


ENDOGNATHION 


790 


INCISORS 


Endognathion,  36 
Epileptiform  neuralgia,  4426 
Erosion,  304a 

inflammation  of  pulp  as  a  sequence, 

4366 
pathology,  304a 
Eruption  of  deciduous  teeth,  156 
causes,  156 
dates,  176 
normal,  17a 
pathological,  ISa 
theories  of,  156 
permanent  teeth,  286 
dates,  29a 
difficult,  441a 

third  mandibular  molar,  34a 
Estimation  of  arch  in  abnormalities, 

1456 
Excision  of  caries  in  teeth,  3346 
Exognathion,  36 
Exostosis,  439a,  4926 
Expansion  and  contraction  of  amal- 
gams, 3876 
Expansion  of  arch  witli  separation  of 
median     maxillary     suture, 
1536 
Exposure    of    pulp,   accidental,    and 

treatment,  4536 
Extraction  of  tectli.  42a,  640 
accidents  of,  6576 
conditions  calling  for,  6406 
difficulties  of,  6556 
general  principles,  641a 
in  abnormalities  of  position,  1476 
operation  of,  642a 
sequelae,  6586 
sterility  of   field   mth  hypodermic 

injections,  3636 
sterility  of  mouth  before  operating, 

363a 
under  general  anaesthetics,  661a 

Fan-shaped  incisors,   936,   946,   1016, 

105o 
Fatty  degeneration  of  the  pulp,  318a 
Fibroid    degeneration    of    the    J^ulp, 

317a 
Filling-materials,  3566 
amalgams  [see  A),  357a 
appropriate  fillings  at  different  ages, 

361a 
cements  (see  C),  359a 
disadvantages  of,  377a 
dressings,  368a 
gold  [see  G),  3566 
gutta-percha  [see  G),  3606.  401a 
inlays  (see  I),  360a 
gold,  422a 
porcelain,  404a 
plastics  (.see  P),  386a 
qualities  required  of,  386a,  404a 
sterihty  of  materials  used,  3666 
tin,  3576 
Filling  of  teeth,  336a 

cavity    preparation,    general    prin- 
ciples, 3446 
cavities,  treatment  of  shallow,  4526 
dentine,  sensitive,  to  treat,  346a 
examination  of  mouth  and  teeth, 

336o 
exclusion  of  saliva  by,  3376 
drugs,  3396 
napkin,  338a 
rubber-dam,  340a 
saliva  ejector,  340a 
wool  roils,  3396 


Filling  of  Teeth  (eoiiti7iiicfl) — 

objects    and    intentions    of    tooth 
restoration,  34Sa 
arrest  of  caries,  348a 
matrices,  use  of,  355a,  3786 
prevention  of  recurrence,  350a 
restoration    of    function,    353a, 
3546 
separating  teeth.  3436 
gradual,  3436 
immediate,  344a 
sterility    of    field    in    conservative 

operations,  3636 
sterility  of  instruments,  326a,  367a 
First  dentition,  156 
Fixed  appliances  for  regulation  cases, 
169a,  1726 
advantages  and  disadvantages,  1706 
bands  and  bows  (see  B) 
employment  and  principle  of,  2216 
hgatures  used,  1746,  2266 
Flora  of  mouth,  change  of,  in  treat- 
ment of  caries,  3346 
Follicle,  dental,  12a 
Foramen  caecum,  76 
Force  as  regards  movement  of  teeth, 

153a,  221a 
Fractures  of  the  jaw,  690 
of  the  mandible,  690a 
of  the  maxilla,  698a 
of  the  teeth,  5266 

pulp  involvement,  454a 
Fraenum  labii, 
abnormal,  866 

treatment,  87a 
in  deciduous  dentition,  1356 
Fungus  infection  in  the  mouth,  738a 


Galvanic  action  with  amalgams,  3896 

Gemination,  436,  456 

Gold, 

annealing  of,  3715 

as  a  filUng-material,  3566 

cavities,   special    requirements    of, 
3756 

cavities,  suitable,  374a 
unsuitable,  375a 

cohesive,  370a 

cohesiveness,    uses   of   various   de- 
grees, 3796 

combination  with  amalgam,  3766 
with  tin,  3766 

condensation  of,  372a 

foil,  filling  with,  374a 

in  incisors  and  canines,  3805 

in  pits  and  fissures,  3835 

in  labial  and  buccal  cavities,  3846 

hand-pressure  in  working,  378a 

instruments  used,  3785 

mallets,  use  of,  378a 

manipulation  of,  370a 

matrices,  use  of.  3785 

non-cohesive,  373a 

retention-  and  starting-points,  376a 

working  of,  hints  on,  380a 
Gold  crowns,  5616 

pressure-cast  shell  crown,  5706 
Gold  inlays  (see  Inlay).  422a 
Growth  of  jaws,  126,  566 

of  mandible,  246 
Gubernaculum,  115,  16a 
Gums,  blue  line  on,  738a 
Gutta-percha  compounds,  3606,  401a 

apphcation,  method  of.  4026 

as  a  filUng-material,  4016 


Haemorrhage  after  extraction,  treat- 
ment, 659a 
Hare-Up,  46 

Hawley's  arch  estimation,  1456 
Head's  areas,  4446 
Head-gear  and  traction  bar,  216a 
Highton's  device  for  expansion,  170a, 

172a 
Howard  inlay,  409a 
Howship's  lacunae,  28a,  4986 
Hutchinsonian  teeth,  466,  49a 
HyaHne  degeneration  of  pidp,  3186 
Hyperaemia  of  pulp,  3125 
Hypercementosis,  4926 
Hyperplasia     of     cementum,      439a, 

4926 
Hypodermic  injection  and  sterility  of 

field  of  operation,  3636 
Hypoplasia.  47a 

associated  with  rickets,  466,  48a 

congenital,  496 

local  origin,  486 

malnutrition,  47a 


Imbrication,  935,  946,  1016,  105a 
Immediate  regulation.  1616 
Immobility  of  the  mandible,  739a 
Impression  taking, 
bridge-work,  6065 
composition,  160a 
plaster,  1595 
roots  for  crowning,  5545 
methods, 

Lennox's,  5556 
Walker's,  5555 
\rith  core,  5565 
Incisors, 

Angle's    modified    bow    for    move- 
ment, 2386 
approximal    cavities    in,    for    gold 

filhngs,  3806 
fan-shaped  lower,   936,   946,    1015, 
105a 
treatment,  102a 
loss  of  deciduous  prematurely,  and 

after  effects,  896 
overlapping  of  lower,  101a 
postplacement  of  upper,  1006 
regulation  of, 

depression  movement, 

in  both  jaws  simultaneously, 
fixed  apphance,  199a 
removable  apphance,  201a 
in  one  jaw  only, 

fixed  appliance,  201a 
removable  apphance,  201a 
individual  tooth  movement, 
fixed  appliance,  214a 
removable  apphance,  2145 
retention, 

fixed  appliance,  2356 
removable  appliance,  2366 
distal  movement, 

fixed  appliance,  198a 
removable  appliance,  1986 
individual  tooth  movement, 
fixed  appliance,  214a 
removable  apphance,  214a 
retention,  2336 

fixed  appliance,  234a 
removable  appliance,  2345 
elongation, 

in  both  jaws  simultaneously, 
fixed  appliance,  201a 
removable  appliance,  202a 


INCISORS 


791 


MATERIALS 


Incisors  (cotitinued) — 

elongation  [continued] — 
in  one  jaw  only, 

fixed  appliance,  203a 
removable  appliance,  203a 
individual  tooth  movement, 
fixed  appliance,  2146 
removable  appliance,  215a 
retention, 

fixed  appliance,  2366 
removable  appliance,  237a 
labial  movement, 
in  upper  and  lower, 

fixed  appliance,  I95n 
removable  appliance,  1956 
individual  tooth  movement, 
fixed  and  removable  appli- 
ance, 2136 
retention, 

fixed  appliance,  230a 
removable  appliance,  231a 
lingual  movement, 

fixed  appliance,  196a 
removable  appliance,  197a 
individual  tooth  movement, 
fixed  and  removable  appli- 
ance, 214a 
by  head-gear  and  traction  bar, 
216o 
retention, 

fixed  appliance,  2316 
removable  appliance,  233a 
medial  movement, 

fixed  apphance,  198a 
removable  apphance,  1986 
individual  tooth  movement, 
fixed  and  removable  appli- 
ance, 214a 
retention,  2336 

fixed  appliance,  234a 
removable  appliance,  2346 
rotation  movement, 

fixed  appliance,  203a 
removable  apphance,  2036 
individual  tooth  movement, 
fixed  apphance,  203o,  2 lore 
removable  appliance,  2036, 
2156 
retention, 

fixed  appliance,  237a 
removable  appliance,  2376 
rotation  of,  996,  1046 
deciduous,  136a 

treatment,  2036.  215a 
root  movement  of,  21Sa 
Inferior  maxilla,  influence  of  adenoids 

on,  786 
Inferior  protrusion,  1306 
causes,  1306 
treatment,  131a 

in    combination   mth   superior   re- 
trusion,  13,3a 
Inferior  retrusion,  1216 
causes,  123a 
treatment,  125a 

in  combination  -n-ith  superior  pro- 
trusion. 130a 
Injection,  hypodermic,  and  sterihty  of 

field.  3fi36 
Inlay,  gold,  422a 

"advantages    of    east    inlay    over 

foil  fillings,  422(1 
casting  under  pressure,  methods, 

4326 
cavities,  special  requirements  in 
preparation,  4246 


Inlay,  gold  (continued) — 

cavities  suitable  for  inlays,  4246 
that  reach  the  gingival  fine, 
429a 
dimension  changes  in  gold  invest- 
ment, 4226 
in  wax,  423a 
insertion  and  cementation,  4336 
instruments,  special,  424a 
in'vestment  materials,  423a 
metals  used,  and  quality  of,  for 

casting,  4236 
Price's  method,  4316 
retention  of  filUng,  433a 
Taggart's  method,  4306 
wax  model,  to  obtain,  430a 
porcelain,  404a 

cavitj'  preparation,  405a 
combination  iilhngs,  4206 
Ball's  inlays,  4086 
fixing  of  inlay,  420o 
fused  inlay,  to  make.  414a 
Howard  inlay,  409a 
■letfcry  inlay,  409a 
making,  process  of,  408a 
methods, 

baking  in  a  mould,  410a 
effects  of  over-firing,  4136 
firing  the  porcelain,  412a 
furnaces  for  firing,  4126 
gauging  temperature.  413a 
packing  the  porcelain,  4116 
grinding  to  shape.  408a 
Peck's  met  hod  of  making  a  fused 

inlay,  4176 
retention  of  inlays,  419a 
value  as  a  filhug,  404a 
Inostosis,  494a 
Intracranial     affections     of     nerves, 

causing  neuralgia,  4426 
Ionic  medication,  5196 

Jacket  crowns,  572a 
Jaw, 

angle  of,  at  birth,  15a 
development  of,  16,  236 
after  birth,  156 
lower  jaw,  56 
fractures  of,  690 
gro«-th  of,  126,  246,  566 
medial  movement  of  lower, 
both  sides, 

fixed  appliance,  1866 
removable  apphance,  188a 
one  side  onlj-, 

fixed  appliance,  189a 
removable  apphance,  189a 
necrosis  of,  687 
ossification  of.  126 
periosteal  inflammation  of,  4396 
splints,  6926 
Jeffery  inlay,  409a 
.Jumping  the  bite,  1266 
Jurisprudence,  771 

the    dentist    and    his    fellow-prac- 
titioners, 782a 
the  lay  pubhc,  7776 
the  State,  771a 

Lateral  malocclusion,  1346 

treatment,  135a 
Leon  WiUiams's  facing  for  re-facing, 
5916 
modification  of  Buttner  crown,  5866 
Ligatures   used    in    regulation    cases, 
1746,  2186,  2266 


Lingual  inclination  of, 

canines,  lU4a 

posterior  teeth,  1056 

premolars,  1045 
Lip-sucking,  88a 

treatment,  896 
Logan  crowns,  5786 
Logan's    sUde    for   re-facing    crowns, 

591a,  5946 
Long-pin  facings  for  re-facing,  592a 
Loss  of  deciduous  molars, 

conditions  arising  after,  1036 
Lower  incisors  overlapping,  101a 
Luken's  band,  1736 

Macrostoma,  5a 

Mallets  used  for  condensing  gold,  378a 
Malocclusion  (see  also  under  Arcli  and 
AbnormaUties), 
abnormahties  of  position,  mechani- 
cal treatment,  1476 
age  for,  1496 

theoretical  considerations,  1196 
abnormal  formation  of  arch,  99a 

estimation  of,  1456 
abnormal  relationship  between  the 
arches,  1076 
antero-posterior,  116a 
lateral,  1346 

treatment,  I35o 
vertical  occlusion  variations,  1076 
close  bite,  1146 
open  bite,  89a,  108a 
protrusion, 
double,  133a 

causes  and  treatment,  134a 
inferior,  1306 
causes,  1306 
treatment,  131a 
with  superior  retrusion,  133a 
superior,  128a 
causes,  1286 
treatment,  1296 
associated  with  adenoids,  536. 

61a,  786,  109a 
with  inferior  retrusion,  130a 
retrusion, 
double,  1346 

treatment,  135a 
inferior,  1216 
causes,  123a 
treatment,  125a 
with  superior  protrusion,  130a 
superior,  132a 
causes.  1326 
treatment,  133a 
with  inferior  protrusion,  133a 
U-shaped  arch.  1056 

treatment,  106a 
V-shaped  arch,  996,  1056 
treatment,  102a 
Mandible, 

development  of,  56,  106 
dislocation  of,  699a 
growth  of,  236 
immobility  of,  739o 
medial  movement  both  sides, 
fixed  apphance,  1866 
removable  appliance,  188a 
movement  on  one  side  only, 
fixed  and  removable  apphance, 
189a 
Mandibular  third  molar, 

affections  of,  33 
Materials,  size  of,  in  orthodontics,226a 
sterilization  of,  3666 


MATRICES 


792 


MOVEMENT  OF  THE  TEETH 


Matrices,  use  of,  355a,  3786 
Matrix  crown,  559a 
Maxilla, 
development  of,  16.  106 
g^o^vth  of,  236 
Maxillary  sinus, 
at  birth,  15a 
at  teething,  246,  2fia 

between    sixth    and     thirteenth 

year,  30a 
at  twenty-fifth  year,  316 
empyema  of, 
acute,  678 
chronic,  682a 
growth  of,  and  relationship  to  erup- 
tion, 576,  586 
inflammation  of,  causing  neuralgia, 
4426 
Maxillary  suture, 

separation  of,  during  expansion  of 
arch,  1536 
Mechanical   stresses    of    mastication, 
529a 
in  normal  arches  and  conditions, 
amount  of,  529a 
direction  of,  529a 
under  abnormal  conditions,  5316 
effects  of  loss,  5326 
effects  of  malposition,  5316 
in  relation  to  bridge-work,  5346 
Meckel's  cartilage,   56,   96,    10a,    126, 

136,  15a 
Mercury,  amount  and  distribution  in 

amalgam,  388a 
Mesognathion,  36 
Metallography  of  amalgams,  3966 
Metals,    ill-efiects  of,   in  the  mouth, 

1616 
Micrometer  for  amalgams,  3956 
Micro-organisms  of  caries  (see  Caries), 

2996 
Micro-stoma,  5a 
Molars, 
deciduous,  associated  with  abnormal 

arch,  99a 
deciduous,  loss  of,  associated  with 

abnormal  arch,  1036 
eruption  and  relationsliip  to  growth 

of  maxillary  sinus,  576 
regulation  of, 

buccal  movement,  upper  or  lower, 
principle  of,  2216 

fixed  appliance,    183a 
removable  appliance,  1836 
retention, 

fixed  appliance,  230a 
removable  appliance,  231a 
movement  on  one  side  only, 
fixed  appliance,  184a 
removable  appliance,  1846 
retention, 

fixed  appliance,  230a 
removable  appliance,  231a 
depression,  194a 
retention, 

fixed  appliance,  2356 
removable  appliance,  2366 
distal  movement  on  both  sides, 
first  molar, 
fixed  appliance,  189a 
removable  appliance,  190a 
by  head-gear  and  traction 
bar,  216a 
retention,  2336 

fixed  appliance,  234a 
removable  appliance,  2346 


Molars  {continued) — 

distal  movement  on  one  side  only, 
first  molar, 

fixed  apphance,  191a 
removable  apphance,  191a 
by  head-gear  and  traction 
bar,  216a 
retention,  2336 

fixed  appliance,  234a 
removable  appliance,  2346 
movement  in  lower  jaw, 
fixed  appliance,  193a 
removable  appliance,  193a 
retention, 

fixed  appliance,  234a 
removable  appliance,  2345 
elongation, 

in  both  jaws  simultaneously, 
fixed  appliance,  194a 
removable  appliance,  194a 
retention, 

fixed  appliance,  2366 
removable  appliance,  237a 
in  one  jaw  only, 

fixed  appliance,  1946 
removable  appliance,  195a 
retention, 

fixed  appliance,  2366 
removable  appliance,  237a 
lingual  movement,  upper  or  lower, 
both  sides, 
first  molar, 

fixed  appliance,  185a 
removable  appliance,  1856 
retention, 

fixed  appliance,  2316 
removable  appliance.  233a 
movement  on  one  side  only, 
first  molar, 

fixed  appliance,  1855 
removable  appliance,  186a 
retention, 

fixed  appliance,  2316 
removable  appliance,  233a 
medial  movement, 

collective      movement      not 
needed,  182,  186 
rotation,  195a 
retention, 

fixed  appliance,  237a 
removable  appliance,  2375 
tilting  of,  207a 
Mouth-breathing,  76a 
effects  of,  775,  109a 
Mouth,  diseases  of  the  mucous  mem- 
brane, 736 
Mouth  flora,  change  of,  in  treatment 

of  caries,  3345 
Mouth-washes,  3326 
Movement    of    roots    in    regulation 

cases,  2175 
Movement  of  the  teeth, 

anchorage  (see  A),  1545,  1796 

axial  rotation,  153a 

care    of    mouth    and     appliances, 

1605 
classification,  182 
force,  application  of,  153a,  221a 
major  tooth  movement  of, 
molars  (see  also  M) 
premolars  (see  also  P) 
canines  (see  also  C) 
incisors  (see  also  I) 


Movement  of  the  teeth  (continued) — 
buccal  movement,  upper  or  lower, 
of    molar,   second  premolar, 
and  canine. 

fixed  appliance,  183a 
removable  appliance,  1835 
retention, 

fixed  appliance,  230a 
removable  appliance,  231rt 
movement  on  both  sides, 
first  premolar,  and  canine, 
fixed  appliance,  1836 
removable  appliance,  184a 
retention, 

fixed  appliance,  230n 
removable  appliance, 

231a 
movement   on    one   side   only, 
molar,  premolar,  and  canine, 
fixed  appliance,  184a 
removable  appliance, 

1846. 
retention, 

fixed  appliance,  230« 
removable  appliance,  231a 
depression,  194a 
retention, 

fixed  appliance,  2356 
removable  appliance,  2366 
distal  movement  both  sides, 
first    molar,    and    second 
premolar, 
fixed  appliance,  189a 
removable  appliance,  190a 
by  head-gear  and  traction 
bar,  21<)a 
retention,  2336 

fixed  appliance,  234a 
removable  appliance,  2345 
movement  on  one  side  only, 
first  molar   and  second  pre- 
molar, 
fixed  appliance,  191a 
removable  appliance,  191a 
by  head -gear  and  traction 
bar.  216a 
retention.  2336 

fixed  appliance,  234a 
removable  appliance,  2346 
movement  on  both  sides, 
first  premolar  and  canine, 
fixed  apphance,  192a 
removable  appliance,  193a 
by  head-gear  and  traction 
bar,  216a 
retention,  2335 

fixed  appliance,  234a 
removable  appliance,  2346 
movement  on  one  side, 
first  premolar  and  canine, 
fixed   and   removable   ap- 
pliance, 193a 
by  head-gear  and  traction 
bar,  216a 
retention,  2336 

fixed  appliance,  234a 
removable  appliance,  2345 
movement  in  lower  jaw, 
first  premolar  and  canine, 
fixed  appliance,  193a 
removable  appliance,  193a 
retention, 

fixed  appliance,  235a 
removable  appliance,  2355 


MOVEMENT  OF  THE  TEETH 


793 


MOVEMENT  OF  THE  TEETH 


Movement  of  the  teeth  {continued) — 
elongation  in  both  jaws  simultane- 
ously, 
molars,   premolars,  and   ca- 
nines, 
fixed  appliance,  1 04a 
removable  appliance,  194o 
retention, 

fixed  appliance,  236fc 
removable  appliance,  237a 
movement  in  one  jaw  only, 
fixed  appUance,  1946 
removable  apphance,  195a 
retention, 

fixed  appliance,  236b 
removable  appliance,  237a 
lingual  movement,  upper  or   lower, 
both  sides, 
first  molars  and  second  pre- 
molars, 
fixed  appUance,  185a 
removable  apphance,  1856 
retention, 

fixed  appliance,  2316 
removable  appliance,  233a 
movement  on  one  side  only, 
first  molar  and   second   pre- 
molar, 
fixed  appliance.  1856 
removable  appUance,  I860 
retention, 

fixed  appUanee,  2315 
removable  appliance,  233a 
movement  on  both  sides, 
first  premolars  and  canines, 
fixed  appUance,  186a 
removable  appliance,  186a 
retention,    fixed    appliance, 
2315 
removable  appliance,  233a 
medial  movement, 

lower  jaw  on  botli  sides, 
fixed  appliance.  1866 
removable  appUance,  188a 
retention, 

fixed  appliance,  235a 
removable  appliance,  2355 
movement  on  one  side  only, 
fixed   and   removable   ap- 
pUance,  189a 
retention, 

fixed  appliance,  235a 
removable  appliance,  2355 
rotation, 

molars,  premolars,  and  canines 
(see minor  toolh  movement) 
minor  or   individual  tooth    move- 
ment, 204a 
canines,  buccal  movement, 
fixed  apphance,  2105 
removable  appUance,  211a 
retention, 

fixed  appliance.  230a 
removable  appliance,  231a 
depression  movement,  213a 
retention, 

fixed  appliance,  2356 
removable  appliance,  2365 
distal  movement, 

fixed  appliance,  2125 
removable  appliance,  2 1 3a 
by  head-i;ear  and  traction 
bar,  2 1 60 
retcnticm,  2336 

fixed  appliance,  234a 
removable  appliance,  2346 


Movement  of  the  teeth  (continued) — 
rotation  (continued) — 

canines,  elongation  movement, 
fixed  appUance,  il'ia 
removable  appUance,  213(i 
retention, 

fi.xed  appliance,  2365 
removable  appliance,  237n 
Ungual  movement, 

fixed   and   removable   ap- 
pliance, 2115 
retention, 

fixed  appliance,  2316 
removable  appliance,  233a 
mcilial  movement, 

fixed   and   removable   ap- 
pUance, 212a 
retention,  2335 

fixed  appliance,  234a 
removable  appliance,  2346 
rotation  movement, 

fixed    and   removable   ap- 
pliance, 2135 
retention, 

fixed  appliance,  237a 
removable  appliance,  2375 
incisors, 

depression  movement, 

fixed  appliance,  214a 
removable  appliance,  2146 
retention, 

fixed  appliance,  2355 
removable  appliance,  2365 
distal  movement, 

fixed  appliance,  214a 
removable  appliance,  214a 
retention,  2336 

fixed  appliance,  234a 
removable  appliance,  2346 
elongation  movement, 
fixed  appliance,  2145 
removable  appliance,  215rt 
retention, 

fixed  appliance,  2365 
removable  appliance,  237a 
labial  movement, 

fixed  appUanee,  2135 
removable  appUanee,  2136 
retention, 

fixed  appliance,  230f( 
removable  appliance,  231a 
lingual  movement, 

fixed  appUanee,  214a 
removable  appliance,  214a 
by    head-gear    and    traction 
bar,  216a 
retention, 

fixed  appliance,  2315 
removable  appliance,  233a 
medial  movement, 

fixed  appUance.  214a 
removable  appliance,  214a 
retention,  2335 

fixed  appliance.  234a 
removable  appliance,  2345 
rotation  movement, 

fixed  appUanee,  203a,  215a 
removable  appUance,  2036, 
2155 
retention. 

fixed  appliance,  237a 
removable  appliance,  2376 
molars, 

buccal  movement, 

fixed  appliance.  204a 
removable  appliance,  2046 


206a 


237a 


Movement  of  the  teeth  (continued) — 
molars,     buccal    movement     (con- 
tinued)— 
retention, 

fixed  appliance,  230a 
removable  appliance,  231a 
depression  movement . 

fixed  appUance,  2055 
removable  appUance,  2055 
retention, 

fixed  appliance,  2355 
removable  appliance,  23(>6 
distal  movement, 

fixed     and     removable     ap- 
pliance, 2056 
by    head-gear   and    traction 
bar,  216a 
retention,  2336 

fixed  appUance,  234a 
removable  appliance,  2345 
elongation  movement, 

fixed  appUance,  2056 
removable  appliance, 
retention, 

fixed  appliance,  2366 
removable  appliance, 
lingual  movement, 

fixed  appliance,  205a 
removable  appliance,  205a 
retention, 

fixed  appliance,  2315 
removable  appliance,  233a 
medial  movement, 

fixed  appUance,  205a 
removable  appUance.  205a 
retention,  2336 

fixed  appUance,  234a 
removable  appliance,  2345 
rotation  movement, 

fixed  appUance,  206a 
retention, 

fixed  appliance.  237a 
removable  appliance,  2376 
premolars      (including      deeiducuis 
molars), 
buccal  movement, 

fixed  appliance,  2075 
removable  appliance,  208a 
retention, 

fixed  appliance.  230o 
removable  appliance,  23Ia 
depression  movement,  210a 
retention, 

fixed  appliance,  2356 
removable  appliance.  ; 
distal  movement. 

fi.xed  appliance,  210a 
retention.  2335 

fixed  appUance,  234a 
removable  appliance, 
elongation  movement. 

fixed  appliance.  210a 
removable  appliance.  210a 
retention, 

fixed  appliance.  2366 
removable  appliance,  237a 
Ungual  movement, 

fixed  appliance,  208a 
removable  appUanee,  2085 
retention, 

fixed  appliance,  2315 
removable  appliance,  233a 
medial  movement. 

fixed     and     removable     ap- 
pliance. 209a 


>366 


2345 


MOVEMENT  OF  THE  TEETH 


794 


PLUMBISM 


Movement  of  the  teeth  (continued)  — 
premolars,  medial  movement  [con- 
tinued]— 
retention,  233i 

fixed  appliance.  234a 
removable  appliance,  2345 
rotation  movement, 

fixed     and     removable     ap- 
pliance, 2106 
retention, 

fixed  appliance,  237a 
removable  appliance,  2376 
mechanics  of,  1506 
physiology  of.  1506 
pulp,  death  of,  in,  153rt 
reciprocal  action,   1506 
treatment, 

by  appUances,  167 
prehminaries  of,  159a 
surgical,  1616 
varieties  of,  181a 
Mucous  membrane  of  the  mouth, 

diseases  of,  736 
Multilocular  C3'sts,  7426 

Nasal     obstruction     and     effect     on 
grovth  of  bone,  76a 
effects  of,  776 
Nasmyth's  membrane  in  caries,  296a 
Naso-orbital  cleft,  5« 
Necrosis  of  the  jaw, 
causes,  687 
treatment,  689a 
of  the  pulp,  320a 
Nerves,    intra-cranial    affections     of, 

causing  neuralgia,  4425 
Neuralgia,  440 
arising  from, 

difficult  eruption  and  malposition 

of  teeth,  441a 
edentulous  patients,  4416 
general  systemic  conditions,  440a 
intra-cranial  affections,  4426 
maxillary  sinus,  inflammation  in, 

4426 
odontomes,  4416 
conditions  ■which  mav  give  rise  to, 

436a 
diagnosis  of,  443a 
Head's  areas  in  relation  to,  4446 
treatment  by  ionic  medication,  5236 

Occlusion,  526 
curve  of,  276 

normal  or  sub-normal.  1216 
Odontalgia,  436 
arising  from, 

alveolar  abscess,  4386 

attrition,  4366 

caries,  4366 

cementum,  exposure  of.  439rt 

hyperplasia  of.  439rt 
erosion.  4366 

periodontitis,   due   to   direct   in- 
jury, 4376 
periosteal   inflammation   of  jaw, 

4396 
pulp  exposure  due  to  fracture  of 
tooth,  4366 
septic  extension  from,  438a 
ulceration  in  the  mouth,  4395 
conditions  which  may  give  rise  to, 

436a 
diagnosis,  aids  to.  443a 
Head's  areas  in  relation  to,  4446 


Odontomes,  436.  740 
causing  neuralgia,  4416 
classification,  741a 
diagnosis  of,  762a 
varieties, 

carcinomatous.  752a 
composite.  7526 
complex.  7536 
compound.  7565 
dilated,  7596 
geminated,  7576 
gestant,  75Sa 
connective     tissue     odontomes, 
7606 
cementomes,  7615 
fibrous,  7616 
sarcomatous,  762a 
enamel  nodules.  759a 
epithelial  (see  also  Cysts),  742« 
Open  bite.  S9a.  108a 

treatment,  1126 
Oral  fluids,  action  on  amalgam,  3895 
Oral  hygiene,  328a 

cleansing  by  artificial  means,  330a 
natural  means,  329a 
Oral  sepsis,  701 

diseases  associated  with,  702a 
Orthodontics,  technique  of,  2226 
Ossification    and    gro^vth    of     jaws, 

126 
Osteo-plastic  cements,  397n 
oxy-chloride  of  zinc,  3996 
oxy-phosphate  of  copper,  400a 
oxy-phosphate  of  zinc.  397a 
oxy-sulphate  of  zinc,  3996 
siheious  cements,  400a 
Overbite  in  deciduous  dentition,  136a 
Overlapping  of  lower  incisors,  101a 


Pain, 

after  extraction,  6586 
diagnosis  of  cause  of.  435 
Head's  areas  in  relation  to.  4446 
Palladium  amalgam.  392a 
Parrot  bite.  1146 
Partial  crowns,  596a 
Peck's   method   of   making   porcelain 

inlays,  4176 
Periodontal  membrane, 
anatomy  of,  487a 
diseases  of,  4S7a 
Periodontitis, 
acute  local,  488 
aetiology.  488a 
pathology  and  morbid  anatomy, 

4886 
signs  and  symptoms,  489a 
treatment,  490a 

by  ionic  medication,  5215 
chronic  local,  491 
aetiology,  491a 
pathology,  4916 
signs  and  symptoms,  492a 
treatment,  4926 
chronic  suppurative,  502 
aetiology,  5036 
organisms  present,  512a 
patholog}',  505a 
signs  and  symptoms,  5066 
treatment,  507a 

by  ionic  medication,  5215 
prophylactic.  5066 
due  to  direct  injury,  4376 
due  to  septic  exten.si(m  from  pulp, 
438a 


Periodontitis  [continued) — 
general,  500 

aetiology,  5006 
productive,  4926 
causes,  493a 
symptoms.  495n 
treatment,  4956 
rarefying,  4976 
causes,  4976 
sj-mptoms,  499a 
Periosteal  inflammation  of  jaw,  4396 
Permanent  dentition, 
development  of,  26a 
eruption  of,  286 
dates,  29a 
Permanent  teeth, 
abnormalities  of,  38 
absence  of,  39a,  866 
cause,  396 
total  absence,  386 
absorption,  316,  36a 
calcification,  126,  25a 
development,  26a 
diseases  associated  with  eruption, 

296 
first     permanent     molars,    impor- 
tance of,  976 
form,  405,  856 

treatment,  86a 
loss  of  first  permanent  molars, 
early,  956 

treatment,  965 
late,  966 

treatment,  97o 
loss   of   one  molar  on  either  side, 
97rt 
treatment.  976 
loss  of  other  permanent  teeth,  985 
loss  premature,  896 
number.  386 

excess  in,  40a 
size,  38a 
structure,  466 
variations, 

in  mandibular  teeth.  425 
in  maxillary  teeth.  41a 
Physiology  and  mechanics  of  artificial 

tooth  movement.  1505 
Pivot  crown,  587a 
Plastic  fillings,  386a 
amalgam,  3o7a.  386a 

ageing  or  annealing  of  comminu- 
ted amalgam  alloys.  389a 
alteration  in  form  of,  3876 
copper,  391a 
mercury,  amount  and  distribution 

in,'  388a 
metallography  of,  3965 
mixing  of,  3926 
oral  fluids,  action  on,  3895 
packing,  method  of,  394« 
palladium,  392a 
physical  examination  of.  395a 
stress. 

crushing,  3886 

dynamometer    for    measuring, 
"3966 
mechanical    changes    in    form 
due  to,  3886 
silver-tin  alloy  modified,  390a 
Gutta-percha  compounds,  3606, 401a 
application,  method  of,  4026 
as  a  fiUing-material.  4016 
Osteo-plastic   cements    [see    Osteo- 
plastics), 397a 
Plumbism  and  blue  line,  738a 


PORCELAIN  BRIDGES 


795 


REFLEX  AFFECTIONS 


Porcelain  bridges,  6286 
cast-gold  crowii,  589a 
crowns  ready-made,  573!),  5786 

to  make,  57-4a 
faced  cap  crowns,  5716 
faced  cast -gold  crown,  5896 
facings  to  replace  {see  also  Crowns), 

d90a 
inlays  {see  Inlay),  404a 
Posts  for  crowning,  553a 

for  crown  and  bridge-work,  616a 
Post  placement     of     upper     incisors, 

1006 
Premolars, 

buccal  or  lingual  inclination,  1046 

treatment,  106a 
major  tooth  movement, 

buccal  movement,  upper  or  lower, 
both  sides, 
second  premolar, 

fixed  appliance.  183a 
removable  appliance,  1836 
first  premolar, 

fixed  appliance,  1836 
removable  appliance,  184a 
retention, 

fixed  appliance,  230a 
removable  appliance,  231a 
buccal  movement  one  side  only, 
fixed  appliance,  184a 
removable  appliance,  1846 
retention, 

fixed  appliance,  230a 
removable  appliance,  231a 
depression,  194a 
distal  movement  both  sides, 
first  premolars, 

fixed  appliance,  192a 
removable  appliance,  193a 
second  premolars, 
fixed  appliance,  189a 
removable  appliance,  190a 
retention,  2336 

fixed  appliance,  234o 
removable  appliance,  2346 
movement  on  one  side  only, 
first  premolar, 
fixed    and   removable  ap- 
pUance,  193a 
second  premolar, 

fixed   and    removable   ap- 
pliance, 191a 
retention,  2336 

fixed  appliance,  234a 
removable  appliance,  2346 
elongation   in    both   jaws   simul- 
taneously, 
fixed   and  removable  ap- 
pliance, 194a 
in  one  jaw  only, 

fixed  appUance,  1946 
removable  appUance,  195a 
retention, 

fixed  appliance,  2366 
removable  appliance,  237a 
lingual  movement,  upper  or  lower, 
both  sides, 
first  premolars, 

fixed   and  removable   ap- 
pliance, 186a 
second  premolars, 
fixed  appliance,  185a 
removable  appliance,  1856 
retention, 

fixed  appliance,  2316 
removable  appliance,  233a 


Premolars  {continued) — 

lingual    movement    on   one  side 
only, 
first  premolar, 
fixed  and  removable  appU- 
ance, 1866 
second  premolar, 

fixed  appUance,  1856 
removable  appUance,  186a 
retention, 

fixed  appliance,  2316 
removable  appliance,  233a 
rotation,  195a 
minor    or    individual    tooth    move- 
vient. 
buccal  movement, 

fixed  appUance,  2076 
removable  appliance,  208a 
retention, 

fixed  appliance,  230n 
removable  appliance,  231a 
depression  movement,  210a 
retention, 

fixed  appliance,  2356 
removable  appliance,  2366 
distal  movement, 

fixed  appUance,  210o 
retention,  2336 

fixed  appliance,  234a 
removable  appliance,  2346 
elongation  movement, 

fixed   and    removable  appli- 
ance, 210a 
retention, 

fixed  appliance,  2366 
removable  appliance,  237a 
lingual  movement, 

fixed  appUance,  208a 
removable  appUance,  2086 
retention, 

fixed  appliance,  2316 
removable  appliance,  233a 
medial  movement, 

fixed  appliance,  209a 
removable  appliance,  209o 
retention,  2336 

fixed  appliance.  234a 
removable  appliance,  2346 
rotation  movement, 

fixed  appliance.  2106 
removable  appliance,  2106 
retention. 

fixed  appliance,  237a 
removable  appliance,  2376 
Prescriptions  for, 

closing    large   apical    openings     in 

roots,  4816 
in     conjunction     with     regulation 

appliances,  161a 
mouth-wash,  3326 
paste  and  powders.  3316 
pulp,  inflammation  of,  368a 
pyorrhoea  alveolaris,  5106 
sensitive  dentine,  347 
Pressure  casting,  applied    to    bridge- 
work,  6256 
gold-shell  crowns.  5706 
Prices  method  for  preparing  wax  for 

gold  inlavs.  4316 
Proclination,  53a,"88a.  956 
I       secondary  to  close  bite.  1 146 
inferior  retrusi(m,  122a 
Prosopometer,  1446 
Protrusion, 
double.  133a 
!  causes  and  treatment,  134a 


Protrusion  {continued)  — 
inferior,  1306 
causes,  1306 
treatment,  131a 
inferior   in    combination    \rith    su- 
perior retrusion,  133a 
superior,  128a 

associated    with    adenoids,    536, 

61a,  786,  109a 
causes,  1286 
treatment,  1296 

superior  in  combination  with  in- 
ferior retrusion,  130a 
Pulp,  diseases  of,  306 
aetiology,  3066 
introduction,  306a 
abscess  and  ulceration,  463a 
anaesthesia  by, 

high-pressure  in  dentine,  4f)0a 
ionic  medication.  5206 
refrigeration,  4606 
atrophic  degeneration,  3176 

management  of,  4626 
calcification  of,  3186 
calcific  deposit  in.  4636 
caries  effects  on,  311a 
crown  and  bridge-work,  pulp  treat- 
ment in,  464a 
death  of,  in  mo\-ing  teeth,  153a 
devitalization,  b}' 
anaesthetics.  4596 
arsenic  {see  A),  4546 
conditions  requiring,  461a 
exposed,  management  of,  461a 
by  accident,  treatment,  4536 
by  caries,  temporary  treatment, 

452a 
when  almost  exposed,  treatment, 
4516 
fatty  degeneration,  318a 
fibroid  degeneration,  317a 
fracture   of  teeth,  involving  treat- 
ment of.  454a 
hyaUne  or  colloid  degeneration,  3186 
hyperaemia  of,  3126 
hypertrophy  of,  462a 
inflammation  of,  3136,  4366 

due  to  attrition,  erosion,  caries, 

4366 
termination  of  inflammation,  315a 
treatment.  4616 
necrosis  and  putrefaction  of,  320a 
receded  pulps,  treatment,  4626 
removal  of,  466a 
retrogressive  changes,  3166 
atrophic  degeneration,  3176 
!  calcification,  3186 

fatty  degeneration,  318a 
fibroid  degeneration,  317a 
hvaline  or  colloid  degeneration. 

3186 
necrosis  and  putrefaction.  320a 
thermal  changes,  effects  on,  312a 
vitality  of,  tests  for,  4736 
Pulp-chambers,  methods  of  opening, 

465a 
Pyorrhoea    alveolaris    {see    Periodon- 
titis), 
pulp  treatment  in.  464a 

Radiography,  712 

diagnosis  by  means  of.  7166 
film  taking  in  mouth,  713a 
stereoscopes,  7146 

Reflex    affections    due    to    diseased 
teeth,  727 


REGULATION  OF  TEETH 


796 


TEETH 


Regulation  of  teeth  (see  also  Move- 
ment of  teeth), 
anchorage  in,  1546,  1796 
arch  estimation  of.  1456 
axial  rotation  in,  153« 
care  of  mouth  and  appliances  in, 

1606 
caries,    complications    caused    by, 

148a 
force     in,     application     of,     153o, 

221a 
metals   used   and   ill-etfects   of,    in 

mouth,  1616 
movement  in, 

mechanics  and  physiology,  1506 
pulp,  death  in,  153a 
reciprocal    action     in     movement, 

1566 
retention  [see  Movement  of  teeth), 

principles  of,  150n,  227a 
root  movement  in  (see  Root), 
treatment  in, 
age  for,  1496 
by  appUances,  167 
fixed,  1726 
metal,  109a 
removable,  169a 
vulcanite,  1696 
extraction,  1476 
general  objects  of,  145a 
immediate  or  surgical,  1616 
mechanical,  1476 
particular  cases,  239a 
prehminaries  of,  159a 
Reichert's  cartilage,  66 
Retained  deciduous  teeth,  84a 

treatment,  846 
Retaining  ap|)liances.  2286 
Retention,  principles  of,  150a,  227a 
Retroclination, 
inferior,  53a,  88a 
superior,  122o 
Retrusion, 
double,  1346 

treatment,  135a 
inferior,  1216 
causes.  123a 
treatment.  125a 
\vith  superior  protrusion.  130a 
superior,  132a 
causes,  1326 
treatment,   133a 
with  inferif)r  protrusion,  133a 
Richmond  crown,  581a 

in    conjunction    with    ready-made 
porcelain,  5846 
Rickets, 

associated  with  adenf)ids,  76a 

hypoplasia,  466,  48a 
effects  on  deciduous  teeth,  186 
Roots, 

absorbed,  punctured,  fractured, 

treatment,  4815 
buried,  surface  indications,  547a 

to  expose,  552a 
movement  of,  by  ligatures,  2186 
movement  of,   in  regulating  teeth, 

2176 
perforation  of,  to  avoid,  546o 
points  in  anatomy  of,  when  crown 

ing,  545a 
preparation  of,  for  crowning,  548a 
suitable  for  crowning,  5396 
Root  -canals, 

constricted,  treatment,  4705 
experimental  filling  of.  4746 


Root-canals  (continued) — 

fiUing-materials  for  and  properties 
of,  478a 
selection  of,  and  technique,  4786 
sterilization    bv   ionic    medication, 

521a 
treatment  of, 

acute  sepsis  in,  4816 
apical  openings  in,  4816 
chronic  sepsis  in,  481o 
dead  pulp  in,  4715 
fractured  broaches  in,  482a 
Rose's  two-part  backing   for   remov- 
able facings,  591a 
Rotation  of  teeth  (see  Movement) 
Rubber-dam,  application  of,  340a 
Rushton's  measurements  for  mandi- 
bular and  profile  angles,  1176 

Saddle  bridges,  623a 
Sahva,  247a 

chemiotaxis,  2495 

constitution  in  health  and  disease, 

2485 
influence  on,  in  caries,  291a 
methods  of  excluding,  3375 
oral  fluids,  action  on  amalgams,  3896 
Sahvary  calculus  (see  Calculus), 
on  teeth,  251o 
treatment,  2526 
SchelUng's    modification   of   a   Coffin 

plate,  1696 
Sclerosis  of  pulp.  317a 
Second  dentition  (see  Permanent),  286 
Sensitive  dentine, 

prescription  for,  347a 
treatment  of,  346a 
Separating  teeth,  methods.  3435 
gradual,  3436 
immediate,  344a 
Sepsis,  oral,  701 

diseases  associated  with,  702a 
Serumal  calculus,  251a 
Shell  crown,  enamelling  of.  571a 
Shriver's   bridge-repairing    drill   anil 

pliers,  5936 
Siegfried  spring,  211a,  217a 
SiUcioiis  cements.  400o 
Silver-tin  alloy,  390a 
Size  of  materials  used  in  orthodontics. 

226a 
Soldering  in  mouth  to  repair  facings, 

5936 
Spee,  curve  of.  276 
Sphnts  for  fractures  of  the  jaw,  6926 
Stains  on  teeth,  254a 

treatment,  2545 
Steele's  facings  for  crowns,  5906 
Stomatitis, 

clironic,  general,  septic,  737a 
mercurial,  7376 
ulcerative,  7366 
Stress  on  amalgams  (see  Amalgam) 
Stresses  of  mastication,  529a 

in  normal  arches  and  conditions, 
amount  of,  529a 
direction  of,  529a 
in  relation  to  bridge-work,  5345 
under  abnormal  conditions,  5316 
effects  of  loss.  5325 
effects  of  malposition,  5316 
Structure  of  the  teeth, 
abnormalities  in.  465 
Sucking  of  toe.  thumb,  lip,  etc.,  88a, 
96a,  1085 
in  deciduous  dentition,  1356 


Superior    proclination    (see    Proclina- 
tion ) 
protrusion  (see  Protrusion) 
retrusion  (see  Retrusion) 
Supernumerary  teeth,  86a 
deciduous,  446 
origin  of,  12a 

permanent,  12a,  385,  40a,  86a 
treatment  of.  86a 
Synostosis,  4956 
Syphilis,  effects  on, 

deciduous  dentition,  186,  466,  49a 
permanent  dentition,  49a 
primarv    infection    of   the    mouth. 
738a 


Taggart's  method  for  preparing  wax 

for  gold  inlays,  4306 
Tartar,  2505 

composition,  251a 
deposit,  cause  of,  251a 
sub-gingival,  2515 
treatment,  2525 
Teeth. 

abnormalities  of  position,  52n 
introduction,  52 
aetiological  factors,  68 
classification,  82 
complications  caused  by  caries, 

148a 
crypt,  position  of,  and  total  dis- 
placement, 875 
treatment,  875 
diagnosis  of,  143 
environment,  influence  on.  75a 
fraenum  labii,  causing.  866 
heredity,  influence  of.  on.  <i85 
malocclusion  (.see  Malocclusion) 
neuralgia,  caused  by.  441a 
pathological  influence,  755 
thumb-,    toe-,    and    lip-sucking, 
causing,  88a,  96a,  1085 
treatment,  896 
treatment, 
age  for.  1496 
by  appliances  (see  Regulation). 

167 
by  extraction.  1475 
general  objects  of,  145a 
mechanical,  1476 
preliminaries  of,  159a 
surgical,  1615 
absorption  of  deciduous,  276 

permanent,  316,  3()a 
amputation  of  crowns  of,  5495 
apical    foramina,  time    of    closure, 

309a 
axial  rotation,  153a 
birth,  present  at.  185 
bleaching  by  ionic  medication.  523a 
calcification  of, 

deciduous,  126,  145,  15a5,  25a 
permanent,  25a 
caries  of.  283a 

chemical  constitution  of  teeth  in, 

2895 
defective     formation     of     teeth, 

influence  on,  303a 
relative  liability  of  different  teeth 
to.  293a 
children's,  treatment  of,  483a 
cleansing  of, 

artificial  means,  330a 
natural  means,  329a 
death  of  pulp  in,  153a 


TEETH 


797 


ZAHNLEISTE 


Teeth  (continued) — 

development  of,  1  la,  236 

after  birth,  156,  236 
deciduous  [see  Deciduous) 
dilaceration,  49a 
discoloration,  254a 

due  to  devitalization,  4046 
external  deposit,  254a 
diseased,    associated     with     reflex 

atfections,  727 
dislocation  of,  5246 
displacement  of,  876 
dressings  for,  368a 
elevation    in    socket  from    disuse, 

108o 
eruption  of  {see  E) 
extraction  of  {see  E),  42«.  640 
ClUng  of  {see  F),  336a 

sensitive  dentine,  treatment,  346a 
force  as  regards  movement  and  ap- 
plication of,  153a,  221a 
fracture  of,  5266 

pulp,  treatment  in,  454a 
germs,  development  of,  12a 
injuries  due  to  violence,  524 
concussion,  524a 
dislocation,  5246 

treatment,  5256,  5266 
movement  of  {see  M) 
necrosis  of,  4996 
neuralgia    caused    by  malposition, 

441a 
open  apex,  treatment   of  pulp  in. 
4526 


Teeth  {continued) — 
permanent  {see  P) 
powders  antl  pastes,  3316 
present  at  birth,  186 
separating  of,  methods,  3436 
spUt  teeth,  to  c^o\^^l,  597a 
stains  on,  254a 
sterilization  of  cavities  in.  366a 

of  surface  when  crowning,  366a 
stresses  subjected  to  {see  Stress) 
structural  abnormalities  in,  466 
supernumerary  {see  S) 
vitality,  tests  for,  4736 
Teething     and     diseases     associated 

with.  19a 
Thermal  changes  and  effects  on  pulp, 

312a 
Thumb-,   toe-,  and   lip-sucking,   88a, 
90a,  1086 
treatment,  896 
in  deciduous  dentition,  1356 
Third  mandibular  molar, 

absorption  of  adjacent  tooth,  36a 
affections  of,  33 
anatomical  relations,  33a 
eruption  of,  34a 

mode  and  symptoms  of  infection, 
346 
treatment,  37a 
Thrush  and  its  treatment,  738a 
Tin  for  tilUng  teeth,  3576 
Tongue, 

development  of,  7a 
sucking,  88a 


Tooth-band,  11a 

Trismus,  35a,  7296 

Tube  crown,  5836 

Tubercular  ulceration  of  the  mouth. 

7386 
Tubes, 

direction  of,  1776 

position  of,  177a 

size  of,  in  orthodontics,  226a 
Tumours  {see  Odontomes),  116 

U-shaped  arch,  1056 
Ulcer, 

septic  in  mouth,  7366 

traumatic  in  mouth,  736a 

Variations    in    form    of    permanent 

teeth,  406 
Visceral  arch,  development  of,  1.  106 
V-shaped  arch,  996,  1056 

Wisdom  teeth, 

affections  associated  mth,  33 
anatomical  relations,  33a 
eruption,  34a 

mode  and  symptoms  of  infection, 
346 
treatment,  37a 
with  absorption  of  adjacent  tooth, 
36a 

Zahnleiste,  11a 


Richard  Clay  &  Sons,  Limited, 

brunswick  street,  stamford  street,  3.k. 

and  bungay,  suffolk 


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